Electronic Green Technologies

**Chapter 2**

Applications

*Albert Sabban*

200 MHz to 3 GHz.

**1. Introduction**

**15**

medical applications, sensor chargers

**Abstract**

Wideband Passive and Active

Wearable Energy Harvesting

Systems for Medical and IOT

Demand for green energy is in continuous growth in the last years. Compact efficient antennas are crucial for energy harvesting portable systems. Small antennas have low efficiency. The efficiency of communication and energy harvesting systems may be improved by using efficient passive and active antennas. The system dynamic range may be improved by connecting amplifiers to the small antenna feed line. Novel passive and active portable harvesting systems are presented in this chapter. Printed patch, notch and Slot antennas are compact and have low volume. The active antennas may be employed in energy harvesting wearable systems. The antennas and the harvesting system components may be assembled on the same printed board. The printed notch and slot antennas bandwidth are from 40 to 100% for VSWR better than 3:1. The slot antenna gain is around 3 dBi with efficiency higher than 85%. The antennas' electrical parameters were computed in free space and near the human body. The active notch antenna gain is around 23 3dB for frequencies ranging from 200 to 900 MHz. The active notch antenna gain is 13 3 dB for frequencies ranging from 1 to 3 GHz. The active notch and slot antenna noise figure is 0.5 0.3dB for frequencies ranging from

**Keywords:** energy harvesting systems, wearable sensors, active systems,

these different types of energy sources have been developed [1–3]. Energy harvesting systems may eliminate the need to replace batteries everyday and the usage of power cords. In order to use as much free space energy as possible, it is important to collect the electromagnetic power from several wireless communication systems. In these cases, we should use wideband or multiband antennas. The energy harvesting antenna must satisfy several specific requirements related to the system application. Due to considerably low-power densities, highly efficient

In the last decade, the idea of employing free space energy in the forms of heat, light, vibration, electromagnetic waves, muscle motion, and other types of energy has become useful and attractive. A number of methods to produce electricity from

#### **Chapter 2**

## Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT Applications

*Albert Sabban*

### **Abstract**

Demand for green energy is in continuous growth in the last years. Compact efficient antennas are crucial for energy harvesting portable systems. Small antennas have low efficiency. The efficiency of communication and energy harvesting systems may be improved by using efficient passive and active antennas. The system dynamic range may be improved by connecting amplifiers to the small antenna feed line. Novel passive and active portable harvesting systems are presented in this chapter. Printed patch, notch and Slot antennas are compact and have low volume. The active antennas may be employed in energy harvesting wearable systems. The antennas and the harvesting system components may be assembled on the same printed board. The printed notch and slot antennas bandwidth are from 40 to 100% for VSWR better than 3:1. The slot antenna gain is around 3 dBi with efficiency higher than 85%. The antennas' electrical parameters were computed in free space and near the human body. The active notch antenna gain is around 23 3dB for frequencies ranging from 200 to 900 MHz. The active notch antenna gain is 13 3 dB for frequencies ranging from 1 to 3 GHz. The active notch and slot antenna noise figure is 0.5 0.3dB for frequencies ranging from 200 MHz to 3 GHz.

**Keywords:** energy harvesting systems, wearable sensors, active systems, medical applications, sensor chargers

#### **1. Introduction**

In the last decade, the idea of employing free space energy in the forms of heat, light, vibration, electromagnetic waves, muscle motion, and other types of energy has become useful and attractive. A number of methods to produce electricity from these different types of energy sources have been developed [1–3]. Energy harvesting systems may eliminate the need to replace batteries everyday and the usage of power cords. In order to use as much free space energy as possible, it is important to collect the electromagnetic power from several wireless communication systems. In these cases, we should use wideband or multiband antennas. The energy harvesting antenna must satisfy several specific requirements related to the system application. Due to considerably low-power densities, highly efficient

radiators are crucial. The antennas should operate at a specific frequency range and polarization. The antenna radiation pattern should have a wide beam width or omnidirectional radiation pattern. Several printed antennas were employed for harvesting energy applications [4–6]. Patch and slot antennas are widely used in communication and medical system [7–24]. Wideband compact slot and notch antennas are good choice to function in wearable harvesting energy systems. Slot and notch antennas are compact and flexible and have low production cost. Moreover, a compact low-cost feed network may be achieved by integrating the amplifiers with the antennas on the same substrate. Printed wearable antennas are widely presented in the literature in the last decade as referred in [7–26]. The human body effect on the electrical performance of wearable antennas at microwave frequencies is not always presented in the literature. Electrical properties of human tissues have been investigated in several papers such as [27, 28]. Several wearable antennas have been presented in papers in the last decade as referred in [22, 28–36]. Wearable printed notch and slot antennas for harvesting energy applications are rarely presented in the literature. A new class of wideband passive and active wearable antennas for harvesting energy applications is presented in this chapter. The system efficiency and dynamic range may be improved by connecting amplifiers to the antenna feed line. The active antenna gain is around 23 dB, and the active antenna noise figure is 0.3 dB for frequencies from 200 to 600 MHz.

#### **2. Energy harvesting systems**

In RF energy harvesting systems, electromagnetic waves propagating in free space are captured, stored, and used to charge batteries and for other applications. There is a significant increase in the amount of electromagnetic energy in the air. The expected amount of radio wave in the air in 2013 was 1.5 exabytes per month. However, the expected amount of radio wave in the air in 2017 was 11 exabytes per month (see **Table 1**). Today we can do more computations per kWh as listed in **Table 2**. Energy sources used in harvesting systems are listed in **Table 3**. Wireless communication systems operate in the frequencies from 700 to 2700 MHz. Medical systems operate in the frequencies from 200 to 1200 MHz. WLAN systems operate in the frequencies from 5400 to 5900 MHz.

RF energy is inversely proportional to distance and therefore drops as the distance from a source is increased. Harvested power from RF energy sources is around 0.1 μW/cm2 . Harvested power from RF energy sources in malls and stadiums may increase to around 1 mW/cm2 . RF energy harvesting concept is shown in **Figure 1**.

The RF energy harvesting system consists of an antenna, a rectifying circuit, and a rechargeable battery. The harvesting energy system operates as a dual mode energy harvesting system. The low-noise amplifier is part of the receiving system. The LNA DC bias voltages are supplied by the receiving system. We can calculate the energy harvesting link budget by using Eqs. (1–4):


*Pr* ¼ *PtGtGr*

equation, where, *Lp* <sup>¼</sup> <sup>4</sup>*π<sup>R</sup>*

*Dual mode energy harvesting concept.*

**Table 2.**

**Table 3.**

**Figure 1.**

**17**

*Computations per kWh.*

Thermal Human

Vibration �Hz—human

*DOI: http://dx.doi.org/10.5772/intechopen.89699*

Electromagnetic 900–2700 MHz

*Energy sources used in harvesting systems.*

Industrial

�kHz—machines

Wi-Fi, WLAN

*λ* <sup>2</sup> .

Free-space loss (Lp) represents propagation loss in free space. Losses due to attenuation in atmosphere, La, should also be accounted for in the transmission

**Year Computations per kWh (1E+09)**

*Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT…*

**Energy source Type Efficiency Estimated Harvested Power** Light Outdoor/indoor 10–25% 100 mW/cm<sup>2</sup>

> �0.1% �3%

60 μW/cm<sup>2</sup> �1–10 mW/cm2

�<sup>800</sup> <sup>μ</sup>W/cm3

0.001 μW/cm2

<sup>20</sup>–50% �<sup>4</sup> <sup>μ</sup>W/cm<sup>3</sup>

�50% 0.1 <sup>μ</sup>W/cm<sup>2</sup>

1983 10 1985 50 1987 100 1992 1000 1997 10,000 2003 100,000 2008 1,000,000 2010 15,000,000

Losses due to polarization mismatch, *Lpol*, should also be accounted. Losses associate with receiving antenna, *Lra*, and with the receiver, *Lr*, cannot be neglected in

*λ* 4*πR* <sup>2</sup>

The received power may be given as *Pr* <sup>¼</sup> *PtGtGr*

(1)

*Lp* .

**Table 1.** *Amount of radio wave in free space.* *Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT… DOI: http://dx.doi.org/10.5772/intechopen.89699*


#### **Table 2.**

radiators are crucial. The antennas should operate at a specific frequency range and polarization. The antenna radiation pattern should have a wide beam width or omnidirectional radiation pattern. Several printed antennas were employed for harvesting energy applications [4–6]. Patch and slot antennas are widely used in communication and medical system [7–24]. Wideband compact slot and notch antennas are good choice to function in wearable harvesting energy systems. Slot and notch antennas are compact and flexible and have low production cost. Moreover, a compact low-cost feed network may be achieved by integrating the amplifiers with the antennas on the same substrate. Printed wearable antennas are widely presented in the literature in the last decade as referred in [7–26]. The human body effect on the electrical performance of wearable antennas at microwave frequencies is not always presented in the literature. Electrical properties of human tissues have been investigated in several papers such as [27, 28]. Several wearable antennas have been presented in papers in the last decade as referred in [22, 28–36]. Wearable printed notch and slot antennas for harvesting energy applications are rarely presented in the literature. A new class of wideband passive and active wearable antennas for harvesting energy applications is presented in this chapter. The system efficiency and dynamic range may be improved by connecting amplifiers to the antenna feed line. The active antenna gain is around 23 dB, and the active antenna

In RF energy harvesting systems, electromagnetic waves propagating in free space are captured, stored, and used to charge batteries and for other applications. There is a significant increase in the amount of electromagnetic energy in the air. The expected amount of radio wave in the air in 2013 was 1.5 exabytes per month. However, the expected amount of radio wave in the air in 2017 was 11 exabytes per month (see **Table 1**). Today we can do more computations per kWh as listed in **Table 2**. Energy sources used in harvesting systems are listed in **Table 3**. Wireless communication systems operate in the frequencies from 700 to 2700 MHz. Medical systems operate in the frequencies from 200 to 1200 MHz. WLAN systems operate

RF energy is inversely proportional to distance and therefore drops as the distance

The RF energy harvesting system consists of an antenna, a rectifying circuit, and

**Year Amount of radio wave in free space exabytes per month**

. Harvested power from RF energy sources in malls and stadiums may

. RF energy harvesting concept is shown in **Figure 1**.

from a source is increased. Harvested power from RF energy sources is around

a rechargeable battery. The harvesting energy system operates as a dual mode energy harvesting system. The low-noise amplifier is part of the receiving system. The LNA DC bias voltages are supplied by the receiving system. We can calculate

noise figure is 0.3 dB for frequencies from 200 to 600 MHz.

**2. Energy harvesting systems**

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in the frequencies from 5400 to 5900 MHz.

the energy harvesting link budget by using Eqs. (1–4):

2014 2.6 2015 4.4 2016 7 2017 11

increase to around 1 mW/cm2

*Amount of radio wave in free space.*

0.1 μW/cm2

**Table 1.**

**16**

*Computations per kWh.*


#### **Table 3.**

*Energy sources used in harvesting systems.*

**Figure 1.** *Dual mode energy harvesting concept.*

$$P\_r = P\_t G\_t G\_r \left(\frac{\lambda}{4\pi R}\right)^2\tag{1}$$

Free-space loss (Lp) represents propagation loss in free space. Losses due to attenuation in atmosphere, La, should also be accounted for in the transmission equation, where, *Lp* <sup>¼</sup> <sup>4</sup>*π<sup>R</sup> λ* <sup>2</sup> . The received power may be given as *Pr* <sup>¼</sup> *PtGtGr Lp* .

Losses due to polarization mismatch, *Lpol*, should also be accounted. Losses associate with receiving antenna, *Lra*, and with the receiver, *Lr*, cannot be neglected in

computation of transmission budget. Losses associate with the transmitting antenna as written as *Lta*.

$$P\_r = \frac{P\_t G\_t G\_r}{L\_p L\_a L\_{ta} L\_{ra} L\_{pol} L\_o L\_r} \tag{2}$$

*Pt* = *Pout*/*Lt*, EIRP = *PtGt*.

where *Pt* = transmitting antenna power; *Lt* = loss between the power source and antenna; EIRP = effective isotropic radiated power.

$$P\_r = \frac{P\_t G\_t G\_r}{L\_p L\_d L\_{td} L\_{rd} L\_{pol} L\_{other} L\_r}$$

$$= \frac{EIRP \times G\_r}{L\_p L\_d L\_{td} L\_{rd} L\_{pol} L\_{other} L\_r} \tag{3}$$

$$= \frac{P\_{out} G\_t G\_r}{L\_t L\_p L\_d L\_{td} L\_{rat} L\_{pol} L\_{other} L\_r}$$

where *<sup>G</sup>* <sup>¼</sup> <sup>10</sup> � log *Pout Pin* dB gain in dB; *<sup>L</sup>* <sup>¼</sup> <sup>10</sup> � log *Pin Pout* dB loss in dB. The received power *Pr* in dBm is given in Eq. (4). The received power *Pr* is

commonly referred to as "Carrier Power."

$$P\_r = EIRP - L\_{ta} - L\_p - L\_a - L\_{pol} - L\_{ra} - L\_{other} + G\_r - L\_r \tag{4}$$

Wireless smart phone using standard 802.11 can transmit up to 1 W. PCMCIA cards using standard 802.11 can transmit around 10 mW up to 100 mW.

#### **3. Wideband notch antenna, 2–7.8 GHz, for energy harvesting applications**

A compact notch antenna was printed on a dielectric substrate with dielectric constant of 2.2. The antenna dimensions are 116.4 � 71.4 � 1.2 mm, as presented in **Figure 2**. The antenna bandwidth for VSWR better than 2.5:1 is around 90–100% (see **Figure 3**). The notch antenna has VSWR better than 3:1 at frequencies from 2.1

to 7.8 GHz. The antenna beam width is around 80° at 5 GHz. The antenna gain is around 2.5 dBi at 3 GHz. The notch antenna radiation pattern at 3.5 GHz is

*Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT…*

presented in **Figure 4**. The electromagnetic energy is converted to DC energy by a

**4. New wideband active 0.5–3 GHz energy harvesting notch antenna**

Harvested power from RF transmitting links is usually lower than 0.1 μW/cm<sup>2</sup>

.

rectifying circuit connected to the antenna input. A rechargeable battery is

connected to the output of the rectifying circuit.

Active antennas may improve the energy.

*Radiation pattern of the notch antenna at 3.5 GHz.*

**Figure 3.**

**Figure 4.**

**19**

*A wideband 2–7.8 GHz notch, computed S11.*

*DOI: http://dx.doi.org/10.5772/intechopen.89699*

**Figure 2.** *A wideband 2–7.8 GHz energy harvesting notch.*

*Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT… DOI: http://dx.doi.org/10.5772/intechopen.89699*

**Figure 3.** *A wideband 2–7.8 GHz notch, computed S11.*

computation of transmission budget. Losses associate with the transmitting antenna

*LpLaLtaLraLpolLoLr*

where *Pt* = transmitting antenna power; *Lt* = loss between the power source and

*LpLaLtaLraLpolLotherLr*

*LtLpLaLtaLraLpolLotherLr*

dB gain in dB; *<sup>L</sup>* <sup>¼</sup> <sup>10</sup> � log *Pin*

PCMCIA cards using standard 802.11 can transmit around 10 mW up to 100 mW.

A compact notch antenna was printed on a dielectric substrate with dielectric constant of 2.2. The antenna dimensions are 116.4 � 71.4 � 1.2 mm, as presented in **Figure 2**. The antenna bandwidth for VSWR better than 2.5:1 is around 90–100% (see **Figure 3**). The notch antenna has VSWR better than 3:1 at frequencies from 2.1

*Pr* ¼ *EIRP* � *Lta* � *Lp* � *La* � *Lpol* � *Lra* � *Lother* þ *Gr* � *Lr* (4)

*Pout* 

dB loss in dB.

(2)

(3)

*Pr* <sup>¼</sup> *PtGtGr*

*Pr* <sup>¼</sup> *PtGtGr*

<sup>¼</sup> *EIRP* � *Gr LpLaLtaLraLpolLotherLr*

<sup>¼</sup> *PoutGtGr*

The received power *Pr* in dBm is given in Eq. (4). The received power *Pr* is

Wireless smart phone using standard 802.11 can transmit up to 1 W.

**3. Wideband notch antenna, 2–7.8 GHz, for energy harvesting**

as written as *Lta*.

*Pt* = *Pout*/*Lt*, EIRP = *PtGt*.

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where *<sup>G</sup>* <sup>¼</sup> <sup>10</sup> � log *Pout*

**applications**

**Figure 2.**

**18**

*A wideband 2–7.8 GHz energy harvesting notch.*

antenna; EIRP = effective isotropic radiated power.

*Pin* 

commonly referred to as "Carrier Power."

**Figure 4.** *Radiation pattern of the notch antenna at 3.5 GHz.*

to 7.8 GHz. The antenna beam width is around 80° at 5 GHz. The antenna gain is around 2.5 dBi at 3 GHz. The notch antenna radiation pattern at 3.5 GHz is presented in **Figure 4**. The electromagnetic energy is converted to DC energy by a rectifying circuit connected to the antenna input. A rechargeable battery is connected to the output of the rectifying circuit.

#### **4. New wideband active 0.5–3 GHz energy harvesting notch antenna**

Harvested power from RF transmitting links is usually lower than 0.1 μW/cm<sup>2</sup> . Active antennas may improve the energy.

Improve harvesting system efficiency. A wideband active notch antenna with fractal structure was printed on a 1.2 mm thick with dielectric constant of 2.2. The compact active notch antenna is shown in **Figure 5**. The notch antenna dimensions are 74.5 57.1 mm. The antenna center frequency is 1.75 GHz. The active antenna bandwidth is around 150–200% for VSWR better than 3:1. The notch antenna gain, S21 parameter, is presented in **Figure 6**. The active antenna gain is 23 3 dB for frequencies from 200 to 900 MHz.

The active notch antenna VSWR is better than 3:1 for frequencies from 0.5 to 3 GHz. The antenna beam width is around 84° at 1 GHz. A compact E-PHEMT LNA, low-noise amplifier, is connected to the notch antenna via an input matching network. An output matching network connects the amplifier port to the rectifying circuit. A printed compact DC voltage bias network supplies the bias voltages to the harvesting system. The amplifier specification is listed in **Table 4**. The amplifier

complex S parameters are listed in **Tables 5** and **6**. The amplifier noise parameters

**F-GHz S11 S11° S21 S21°** 0.19 31.76 0.964 24.13 158.9 0.279 0.93 45.77 22.97 149.5 0.323 0.92 53.39 22.45 145.3 0.413 0.89 65.72 20.98 137.27 0.50 0.87 77.1 19.54 130.3 0.59 0.83 87.12 18.08 124.14 0.726 0.8 100.8 16.22 115.7 0.816 0.77 108.8 15.07 110.75 1.04 0.74 126.2 12.74 100.13 1.21 0.71 137.6 11.25 92.91 1.53 0.687 154.2 9.29 82.06 1.75 0.67 164.1 8.24 75.31 2.02 0.67 174.6 7.27 67.82

notch antenna noise figure is 0.5 0.3 dB for frequencies ranging from 300 to 3.0 GHz as presented in **Figure 7**. The active notch antenna output VSWR is better than 3:1 for frequencies from 0.5 to 3 GHz. All antennas presented in this paper can

**Parameter Specification Remarks**

*Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT…*

18 dB at 2 GHz

0.5 dB at 2 GHz

19.1 dBm at 2 GHz

33.6 dBm at 2 GHz

Vgs 0.48 V Vds = 3 V; Ids = 60 mA

Vds = 3 V; Ids = 60 mA

Vds = 3 V; Ids = 60 mA

Vds = 3 V; Ids = 60 mA

Vds = 3 V; Ids = 60 mA

Frequency range 0.4–3 GHz Gain 26 dB at 0.4 GHz

*DOI: http://dx.doi.org/10.5772/intechopen.89699*

Noise figure 0.4 dB at 0.4 GHz

P1dB 18.9 dBm at 0.4 GHz

OIP3 32.1 dBm at 0.4 GHz

Max. input power 17 dBm

Vds 3 V Ids 60 mA Supply voltage 5 V Operating temp. 40–80°C

The active antenna gain is 12 3 dB for frequencies from 1 to 3 GHz. The active

are listed in **Table 7**.

*LNA amplifier specification.*

**Table 4.**

**Table 5.**

**21**

*LNA amplifier S parameters.*

operate as passive and active antennas.

**Figure 5.** *A wideband fractal active notch antenna.*

**Figure 6.** *Active notch antenna S21 parameter.*

**Parameter Specification Remarks** Frequency range 0.4–3 GHz Gain 26 dB at 0.4 GHz 18 dB at 2 GHz Vds = 3 V; Ids = 60 mA Noise figure 0.4 dB at 0.4 GHz 0.5 dB at 2 GHz Vds = 3 V; Ids = 60 mA P1dB 18.9 dBm at 0.4 GHz 19.1 dBm at 2 GHz Vds = 3 V; Ids = 60 mA OIP3 32.1 dBm at 0.4 GHz 33.6 dBm at 2 GHz Vds = 3 V; Ids = 60 mA Max. input power 17 dBm Vgs 0.48 V Vds = 3 V; Ids = 60 mA Vds 3 V Ids 60 mA Supply voltage 5 V Operating temp. 40–80°C

*Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT… DOI: http://dx.doi.org/10.5772/intechopen.89699*

#### **Table 4.**

Improve harvesting system efficiency. A wideband active notch antenna with fractal structure was printed on a 1.2 mm thick with dielectric constant of 2.2. The compact active notch antenna is shown in **Figure 5**. The notch antenna dimensions are 74.5 57.1 mm. The antenna center frequency is 1.75 GHz. The active antenna bandwidth is around 150–200% for VSWR better than 3:1. The notch antenna gain, S21 parameter, is presented in **Figure 6**. The active antenna gain is 23 3 dB for

The active notch antenna VSWR is better than 3:1 for frequencies from 0.5 to 3 GHz. The antenna beam width is around 84° at 1 GHz. A compact E-PHEMT LNA, low-noise amplifier, is connected to the notch antenna via an input matching network. An output matching network connects the amplifier port to the rectifying circuit. A printed compact DC voltage bias network supplies the bias voltages to the harvesting system. The amplifier specification is listed in **Table 4**. The amplifier

frequencies from 200 to 900 MHz.

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**Figure 5.**

**Figure 6.**

**20**

*Active notch antenna S21 parameter.*

*A wideband fractal active notch antenna.*

*LNA amplifier specification.*

complex S parameters are listed in **Tables 5** and **6**. The amplifier noise parameters are listed in **Table 7**.

The active antenna gain is 12 3 dB for frequencies from 1 to 3 GHz. The active notch antenna noise figure is 0.5 0.3 dB for frequencies ranging from 300 to 3.0 GHz as presented in **Figure 7**. The active notch antenna output VSWR is better than 3:1 for frequencies from 0.5 to 3 GHz. All antennas presented in this paper can operate as passive and active antennas.


**Table 5.** *LNA amplifier S parameters.*

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**Figure 7.**

**Figure 8.**

**Figure 9.**

**23**

*A fractal active notch antenna S21 parameter.*

*A wideband fractal active notch antenna with fractal structure.*

*Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT…*

*Active notch antenna noise figure.*

*DOI: http://dx.doi.org/10.5772/intechopen.89699*

#### **Table 6.**

*LNA amplifier S parameters.*


**Table 7.** *LNA noise parameters.*

#### **5. New fractal active 0.4–3 GHz energy harvesting antenna**

A compact notch antenna with fractal structure is shown in **Figure 8**. The antenna is printed on a 5580 Duroid substrate, 1.2 mm thick, with dielectric constant of 2.2. The notch antenna dimensions are 52.2 36.8 1.2 mm. The antenna center frequency is 1.7 GHz. The antenna bandwidth is around 100% for VSWR better than 3:1. The active notch antenna VSWR is better than 3:1 for frequencies from 0.4 to 3 GHz. The antenna beam width is around 82° at 1 GHz. An LNA is connected to the antenna feed line. The antenna is connected to the LNA via an input matching network. An output matching network connects the amplifier output port to a rectifying circuit. A compact DC network supplies the required voltages to the active antenna. The amplifier specification, S parameters, and the

*Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT… DOI: http://dx.doi.org/10.5772/intechopen.89699*

**Figure 7.** *Active notch antenna noise figure.*

**Figure 8.** *A wideband fractal active notch antenna with fractal structure.*

**Figure 9.** *A fractal active notch antenna S21 parameter.*

**5. New fractal active 0.4–3 GHz energy harvesting antenna**

**Table 6.**

**Table 7.**

**22**

*LNA noise parameters.*

*LNA amplifier S parameters.*

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A compact notch antenna with fractal structure is shown in **Figure 8**. The antenna is printed on a 5580 Duroid substrate, 1.2 mm thick, with dielectric constant of 2.2. The notch antenna dimensions are 52.2 36.8 1.2 mm. The antenna center frequency is 1.7 GHz. The antenna bandwidth is around 100% for VSWR better than 3:1. The active notch antenna VSWR is better than 3:1 for frequencies from 0.4 to 3 GHz. The antenna beam width is around 82° at 1 GHz. An LNA is connected to the antenna feed line. The antenna is connected to the LNA via an input matching network. An output matching network connects the amplifier output port to a rectifying circuit. A compact DC network supplies the required voltages to the active antenna. The amplifier specification, S parameters, and the

**F-GHz S12 S12° S22 S22°** 0.19 0.016 74.88 0.54 22.98 0.279 0.021 65.77 0.51 33.65 0.323 0.026 62.38 0.49 39.2 0.413 0.03 57.9 0.46 49.3 0.50 0.034 53.03 0.43 57.5 0.59 0.038 48.18 0.40 64.12 0.726 0.042 42.06 0.36 74.86 0.816 0.044 39.53 0.34 80.87 1.04 0.049 33.69 0.29 94.96 1.21 0.051 30.05 0.26 104 1.53 0.055 26.08 0.22 119 1.75 0.058 23.14 0.20 128.4 2.02 0.06 20.88 0.18 138.8

**F-GHz NFMIN N11X N11Y Rn** 0.4 0.070 0.3276 20.05 0.062 0.5 0.079 0.3284 24.56 0.056 0.7 0.112 0.334 36.08 0.050 0.9 0.144 0.3396 47.4 0.045 1 0.16 0.3424 52.98 0.042 1.9 0.306 0.3682 100.93 0.029 2 0.322 0.3711 106.01 0.029 2.4 0.387 0.3829 125.79 0.029 3 0.484 0.401 153.93 0.036 3.9 0.629 0.429 167.3 0.059 5 0.808 0.4645 125.53 0.11

**Figure 10.** *Active fractal notch antenna noise figure.*

amplifier noise parameters are listed in **Tables 4**–**7**. The active antenna gain is 21 3 dB for frequencies from 400 MHz to 1.3 GHz, as presented in **Figure 9**. The active antenna gain is 12 3 dB for frequencies from 1.3 to 3 GHz. The active notch antenna noise figure is 0.5 0.3 dB for frequencies from 300 MHz to 3.0 GHz, as presented in **Figure 10**. The notch antenna output VSWR is better than 3:1 for frequencies from 0.5 to 3 GHz.

are presented in **Figure 12**. The antenna bandwidth is around 100% for VSWR better than 3:1. The antenna beamwidth is around 138° at 1 GHz as shown in **Figure 13**. The antenna gain is around 2.5 dBi. The antenna was designed also as an active antenna as shown in **Figure 14**. The slot antenna is connected to the LNA via an input matching network. The output matching network connects the amplifier output port to a rectifying circuit. For example, a MMIC LNA with 16 dB gain and 1 dB noise figure has DC power consumption of less than 18 mW in the frequency range from 70 MHz to 1 GHz. The system DC bias network supply the required voltages to the energy harvesting system. The amplifier specification is listed in **Table 5**. The amplifier complex S parameters are listed in **Tables 5** and **6**. The active slot antenna gain, S21 parameter, is presented in **Figure 15**. The active antenna gain is 23 3 dB for frequencies from 200 to 900 MHz. The active antenna gain is 13 3 dB for frequencies from 1 to 3 GHz. The active slot antenna noise

*Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT…*

**Figure 12.**

**Figure 13.**

**25**

*Radiation pattern of the energy harvesting slot antenna.*

*Computed S11 of a wideband, 0.8–5.4 GHz, slot.*

*DOI: http://dx.doi.org/10.5772/intechopen.89699*

#### **6. New wideband active 0.8–5.4 GHz energy harvesting slot antenna**

A wideband T shape wearable slot antenna for energy harvesting applications is shown in **Figure 11**. The antenna electrical parameters were computed by using momentum software [38]. The volume of the T-shape slot antenna is 7 7 0.12 cm. The slot antenna center frequency is around 3 GHz. The computed S11 parameters

**Figure 11.** *A wideband energy harvesting slot antenna.*

*Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT… DOI: http://dx.doi.org/10.5772/intechopen.89699*

**Figure 12.** *Computed S11 of a wideband, 0.8–5.4 GHz, slot.*

amplifier noise parameters are listed in **Tables 4**–**7**. The active antenna gain is 21 3 dB for frequencies from 400 MHz to 1.3 GHz, as presented in **Figure 9**. The active antenna gain is 12 3 dB for frequencies from 1.3 to 3 GHz. The active notch antenna noise figure is 0.5 0.3 dB for frequencies from 300 MHz to 3.0 GHz, as presented in **Figure 10**. The notch antenna output VSWR is better than 3:1 for

**6. New wideband active 0.8–5.4 GHz energy harvesting slot antenna**

A wideband T shape wearable slot antenna for energy harvesting applications is shown in **Figure 11**. The antenna electrical parameters were computed by using momentum software [38]. The volume of the T-shape slot antenna is 7 7 0.12 cm. The slot antenna center frequency is around 3 GHz. The computed S11 parameters

frequencies from 0.5 to 3 GHz.

*Active fractal notch antenna noise figure.*

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**Figure 10.**

**Figure 11.**

**24**

*A wideband energy harvesting slot antenna.*

are presented in **Figure 12**. The antenna bandwidth is around 100% for VSWR better than 3:1. The antenna beamwidth is around 138° at 1 GHz as shown in **Figure 13**. The antenna gain is around 2.5 dBi. The antenna was designed also as an active antenna as shown in **Figure 14**. The slot antenna is connected to the LNA via an input matching network. The output matching network connects the amplifier output port to a rectifying circuit. For example, a MMIC LNA with 16 dB gain and 1 dB noise figure has DC power consumption of less than 18 mW in the frequency range from 70 MHz to 1 GHz. The system DC bias network supply the required voltages to the energy harvesting system. The amplifier specification is listed in **Table 5**. The amplifier complex S parameters are listed in **Tables 5** and **6**. The active slot antenna gain, S21 parameter, is presented in **Figure 15**. The active antenna gain is 23 3 dB for frequencies from 200 to 900 MHz. The active antenna gain is 13 3 dB for frequencies from 1 to 3 GHz. The active slot antenna noise

**Figure 13.** *Radiation pattern of the energy harvesting slot antenna.*

figure is 0.5 0.3 dB for frequencies from 200 MHz to 3.0 GHz. The computed S11 parameters of the T-shape slot on human body are presented in **Figure 16**. The dielectric constant of human body tissue was taken as 45. The antenna was attached to a shirt with dielectric constant of 2.21 mm thick.

**7. Energy harvesting systems for medical and IOT applications**

*Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT…*

*Computed S11 of a wideband, 0.8–5.4 GHz, slot. Antenna on the human body.*

commercial body area networks (BANs).

*DOI: http://dx.doi.org/10.5772/intechopen.89699*

**Figure 16.**

**Figure 17.**

**27**

*Analyzed structure for wearable slot antennas.*

The notch and slot antennas' electrical performance near the human body was investigated by using the model shown in **Figure 17**. Properties of human body tissues are listed in **Table 8** [27, 28]. These properties were employed in the antenna design. Up to four energy harvesting antennas may be assembled in a belt and attached to the patient body as presented in **Figure 18**. The bias voltage to the active elements is supplied by a compact recorder battery. The DC cables from each harvesting antenna are connected to a rechargeable battery. The electromagnetic energy is converted to DC energy that may be employed to charge medical or

**Figure 14.** *A wideband active energy harvesting slot antenna.*

**Figure 15.** *Active energy harvesting slot antenna S21.*

*Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT… DOI: http://dx.doi.org/10.5772/intechopen.89699*

**Figure 16.** *Computed S11 of a wideband, 0.8–5.4 GHz, slot. Antenna on the human body.*

#### **7. Energy harvesting systems for medical and IOT applications**

The notch and slot antennas' electrical performance near the human body was investigated by using the model shown in **Figure 17**. Properties of human body tissues are listed in **Table 8** [27, 28]. These properties were employed in the antenna design. Up to four energy harvesting antennas may be assembled in a belt and attached to the patient body as presented in **Figure 18**. The bias voltage to the active elements is supplied by a compact recorder battery. The DC cables from each harvesting antenna are connected to a rechargeable battery. The electromagnetic energy is converted to DC energy that may be employed to charge medical or commercial body area networks (BANs).

**Figure 17.** *Analyzed structure for wearable slot antennas.*

figure is 0.5 0.3 dB for frequencies from 200 MHz to 3.0 GHz. The computed S11 parameters of the T-shape slot on human body are presented in **Figure 16**. The dielectric constant of human body tissue was taken as 45. The antenna was attached

to a shirt with dielectric constant of 2.21 mm thick.

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**Figure 14.**

**Figure 15.**

**26**

*Active energy harvesting slot antenna S21.*

*A wideband active energy harvesting slot antenna.*

#### *Innovation in Global Green Technologies 2020*


#### **Table 8**

*Electrical properties of human body tissues.*

given in Eq. 5. The rectifier output voltage may be improved by connecting a

*Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT…*

*DOI: http://dx.doi.org/10.5772/intechopen.89699*

*VMAX*

*Vripple* ¼ *Vr* ¼ *Vmax* � *Vmin* ¼ *VDC*

The time constant *τ* should be lower than T, where, *τ* ¼ *RC* ≪ *T*. The half-wave rectifier efficiency is 40.6% as given in Eq. 7. Only 40.6% of the input AC power is converted into DC power. Where rf the diode resistance is negligible as compared to R.

> *Im π* � �<sup>2</sup> *R*

*Im* 2 � �<sup>2</sup>

*<sup>O</sup>* sin ð Þ *ωt d*ð Þ *ωt* ; *ω* ¼ 2*πf*

*<sup>O</sup>* ¼ *Vm*

*=*

ð Þ *<sup>R</sup>* <sup>þ</sup> *rf* � <sup>0</sup>*:*<sup>406</sup> (7)

*fCR* (6)

(5)

capacitor in shunt to the resistor as presented in **Figure 20**.

2*π*

The improved half wave rectifier is shown in **Figure 20**.

*<sup>η</sup>* <sup>¼</sup> DC output power AC input power ¼

2 ð*π*

0

*VO* <sup>¼</sup> *VS* � *VDON* <sup>≈</sup>*VS*; *<sup>V</sup>MAX*

*VO*,*DC* <sup>¼</sup> <sup>1</sup>

**Figure 19.** *Half-wave rectifier.*

**Figure 20.**

**Figure 21.** *Full-wave rectifier.*

**29**

*Improved half-wave rectifier.*

*VODC* ¼ *Vm=π*

**Figure 18.** *Active wearable energy harvesting antennas.*

#### **8. Energy harvesting system**

As presented in **Figure 1**, the energy harvesting system consists of an antenna, a rectifying circuit, and a rechargeable battery. A rectifier is a circuit that converts electromagnetic energy, alternating current AC, to direct current (DC). Half-wave rectifier or full wave rectifier may be used to convert electromagnetic AC energy to DC electrical energy. A half-wave rectifier is presented in **Figure 19**. A half-wave rectifier conducts only during the positive half cycle. It allows only one half of an AC waveform to pass through the load. The rectifier output DC voltage, *VODC*, is

*Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT… DOI: http://dx.doi.org/10.5772/intechopen.89699*

**Figure 20.** *Improved half-wave rectifier.*

given in Eq. 5. The rectifier output voltage may be improved by connecting a capacitor in shunt to the resistor as presented in **Figure 20**.

$$\begin{aligned} V\_{O,DC} &= \frac{1}{2\pi} \int\_0^{2\pi} V\_O^{MAX} \sin\left(\alpha t\right) d(\alpha t); \ \alpha = 2\pi \text{f} \\ V\_O &= V\_S - V\_{DON} \approx V\_S; \ V\_O^{MAX} = V\_m \\ V\_{ODC} &= V\_m/\pi \end{aligned} \tag{5}$$

The improved half wave rectifier is shown in **Figure 20**.

$$Vripple = Vr = Vmax - Vmin = {}^{VDC} \% \text{CR} \tag{6}$$

The time constant *τ* should be lower than T, where, *τ* ¼ *RC* ≪ *T*. The half-wave rectifier efficiency is 40.6% as given in Eq. 7. Only 40.6% of the input AC power is converted into DC power. Where rf the diode resistance is negligible as compared to R.

$$\eta = \frac{\text{DC output power}}{\text{AC input power}} = \frac{\left(\frac{l\_m}{\pi}\right)^2 R}{\left(\frac{l\_m}{2}\right)^2 (R + \eta f)} \sim 0.406\tag{7}$$

**Figure 21.** *Full-wave rectifier.*

**8. Energy harvesting system**

*Active wearable energy harvesting antennas.*

**Figure 18.**

**28**

Fat σ

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Stomach σ

Colon σ

Lung σ

Prostate σ

Kidney σ

*Electrical properties of human body tissues.*

**Table 8**

ε

ε

ε

ε

ε

ε

As presented in **Figure 1**, the energy harvesting system consists of an antenna, a rectifying circuit, and a rechargeable battery. A rectifier is a circuit that converts electromagnetic energy, alternating current AC, to direct current (DC). Half-wave rectifier or full wave rectifier may be used to convert electromagnetic AC energy to DC electrical energy. A half-wave rectifier is presented in **Figure 19**. A half-wave rectifier conducts only during the positive half cycle. It allows only one half of an AC waveform to pass through the load. The rectifier output DC voltage, *VODC*, is

**Tissue Property 600 MHz 1000 MHz**

0.05 5

0.73 41.41

1.06 61.9

0.27 38.4

0. 75 50.53

0.88 117.43 0.06 4.52

0.97 39.06

1.28 59.96

0.27 38.4

0.90 47.4

0.88 117.43

**Figure 22.** *Improved full-wave rectifier.*

The bridge full-wave rectifier circuit is used usually for DC power supplies. It consists of four diodes, D1–D4, as shown in in **Figure 21**, connected to form a bridge. During the positive input half cycle, terminal A will be positive and terminal B will be negative. Diodes D1 and D2 will become forward biased and D3 and D4 will be reversed biased. The rectifier output DC voltage, *VODC* ¼ 2*Vm=π*, may be improved by connecting a capacitor in the shunt to the resistor. The improved halfwave rectifier is presented in **Figure 22**.

The half-wave rectifier efficiency is 81.2% as presented in Eq. 8. This means that only 81.2% of the input AC power is converted into DC power.

$$\eta = \frac{\text{DC output power}}{\text{AC input power}} = \frac{\left(\frac{2l\_m}{\pi}\right)^2 R}{\left(\frac{l\_m}{2}\right)^2 (R + \eta f)} \sim 0.812\tag{8}$$

**Figure 24** presents a wearable harvesting system and a wearable battery charger

*Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT…*

This paper presents new ultra-wideband wearable passive and active energy harvesting systems and antennas in frequencies ranging from 0.4 to 8 GHz. The antennas are inserted in a belt and attached to the body. The antennas are compact and can be attached to the body. The antennas allow the patients' easy movement

The electromagnetic energy is converted to DC energy that may be employed to charge batteries, wearable medical devices, and commercial body area networks. The passive and active notch and slot antennas were analyzed by using 3D full-wave software. Harvested power from RF transmitting links is usually lower than 0.1 μW/

. Active antennas may improve the energy harvesting system efficiency. All antennas presented in this paper can operate also as passive antennas. The active notch and slot antenna bandwidth are from 50 to 100% with VSWR better than 3:1. The slot antenna gain is around 3 dBi with efficiency higher than 90%. The antenna electrical parameters were computed near the human body. The active slot antenna gain is 24 2.5 dB for frequencies ranging from 200 to 900 MHz. The active slot antenna gain is 13 3dB for frequencies from 1 to 3.3 GHz. The active wearable antennas may be used in energy harvesting systems for wireless communication and medical applications. The RF energy harvesting system consists of an antenna, a

attached to the patient shirt.

*Medical wearable harvesting system.*

*Typical I–V curves of Schottky diodes.*

*DOI: http://dx.doi.org/10.5772/intechopen.89699*

(running, jumping, and working).

**9. Conclusion**

**Figure 24.**

**Figure 23.**

cm2

**31**

A capacitor is used in the improved rectifier to get flat output voltage variation as function of time. The capacitor may be a voltage-controlled varactor diode. Varactors are voltage variable capacitors designed to provide electronic tuning of electrical devices. The output voltage ripple (see Eq. 6) of the improved rectifier may be tuned as function of the frequency of the received signal or of the load resistance R.

A Schottky diode may be used in the rectifier circuit. Schottky diodes are semiconductor diodes which has a low forward voltage drop and a very fast switching action. There is a small voltage drop across the diode terminals when current flows through the diode. The voltage drop of a Schottky diode is usually between 0.15 and 0.4 V. This lower voltage drop provides better system efficiency and higher switching speed. A normal diode has a voltage drop between 0.6 and 1.7 V. Electrical characteristics of Schottky diode and standard PN diodes are listed in **Table 9**. Typical I–V curves of commercial Schottky diodes are shown in **Figure 23**.


**Table 9.** *Electrical characteristics of Schottky diode and PN diodes.* *Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT… DOI: http://dx.doi.org/10.5772/intechopen.89699*

**Figure 23.** *Typical I–V curves of Schottky diodes.*

The bridge full-wave rectifier circuit is used usually for DC power supplies. It consists of four diodes, D1–D4, as shown in in **Figure 21**, connected to form a bridge. During the positive input half cycle, terminal A will be positive and terminal B will be negative. Diodes D1 and D2 will become forward biased and D3 and D4 will be reversed biased. The rectifier output DC voltage, *VODC* ¼ 2*Vm=π*, may be improved by connecting a capacitor in the shunt to the resistor. The improved half-

The half-wave rectifier efficiency is 81.2% as presented in Eq. 8. This means that

2*Im π* � �<sup>2</sup> *R*

ð Þ *<sup>R</sup>* <sup>þ</sup> *rf* � <sup>0</sup>*:*<sup>812</sup> (8)

*Im* 2 � �<sup>2</sup>

A capacitor is used in the improved rectifier to get flat output voltage variation

A Schottky diode may be used in the rectifier circuit. Schottky diodes are semiconductor diodes which has a low forward voltage drop and a very fast switching action. There is a small voltage drop across the diode terminals when current flows through the diode. The voltage drop of a Schottky diode is usually between 0.15 and

as function of time. The capacitor may be a voltage-controlled varactor diode. Varactors are voltage variable capacitors designed to provide electronic tuning of electrical devices. The output voltage ripple (see Eq. 6) of the improved rectifier may be tuned as function of the frequency of the received signal or of the load

0.4 V. This lower voltage drop provides better system efficiency and higher switching speed. A normal diode has a voltage drop between 0.6 and 1.7 V. Electrical characteristics of Schottky diode and standard PN diodes are listed in **Table 9**. Typical I–V curves of commercial Schottky diodes are shown in **Figure 23**.

**Parameter Schottky diode PN diode**

Switching speed Fast Limited

*Electrical characteristics of Schottky diode and PN diodes.*

Forward current mechanism Majority carrier transport Minority carrier transport Reverse current Less temperature dependence Strong temperature dependence Turn on voltage Small—around 0.2 V Comparatively large around 0.7 V

only 81.2% of the input AC power is converted into DC power.

*<sup>η</sup>* <sup>¼</sup> DC output power AC input power ¼

wave rectifier is presented in **Figure 22**.

*Innovation in Global Green Technologies 2020*

resistance R.

**Table 9.**

**30**

**Figure 22.**

*Improved full-wave rectifier.*

**Figure 24.** *Medical wearable harvesting system.*

**Figure 24** presents a wearable harvesting system and a wearable battery charger attached to the patient shirt.

#### **9. Conclusion**

This paper presents new ultra-wideband wearable passive and active energy harvesting systems and antennas in frequencies ranging from 0.4 to 8 GHz. The antennas are inserted in a belt and attached to the body. The antennas are compact and can be attached to the body. The antennas allow the patients' easy movement (running, jumping, and working).

The electromagnetic energy is converted to DC energy that may be employed to charge batteries, wearable medical devices, and commercial body area networks. The passive and active notch and slot antennas were analyzed by using 3D full-wave software. Harvested power from RF transmitting links is usually lower than 0.1 μW/ cm2 . Active antennas may improve the energy harvesting system efficiency. All antennas presented in this paper can operate also as passive antennas. The active notch and slot antenna bandwidth are from 50 to 100% with VSWR better than 3:1. The slot antenna gain is around 3 dBi with efficiency higher than 90%. The antenna electrical parameters were computed near the human body. The active slot antenna gain is 24 2.5 dB for frequencies ranging from 200 to 900 MHz. The active slot antenna gain is 13 3dB for frequencies from 1 to 3.3 GHz. The active wearable antennas may be used in energy harvesting systems for wireless communication and medical applications. The RF energy harvesting system consists of an antenna, a rectifying circuit, and a rechargeable battery. The harvesting energy system operates as a dual mode energy harvesting system. The low-noise amplifier is part of the receiving system. The LNA DC bias voltages are supplied by the receiving system.

**References**

2005;**4**(1):18-27

108-120

**2**(1):24-33

[1] Paradiso JA, Starner T. Energy scavenging for mobile and wireless electronics. IEEE Pervasive Computing.

*DOI: http://dx.doi.org/10.5772/intechopen.89699*

[8] Sabban A. Wideband RF Technologies and Antenna in Microwave Frequencies. USA: Wiley

[9] James JR, Hall PS, Wood C.

[10] Sabban A, Gupta KC.

Microstrip Antenna Theory and Design.

Characterization of radiation loss from microstrip discontinuities using a multiport network modeling approach. IEEE Transactions on Microwave Theory and Techniques. April 1991;

[11] Sabban A. A new wideband stacked microstrip antenna. In: IEEE Antenna and Propagation Symp., Houston,

[12] Sabban A, Navon E. A MM-waves microstrip antenna array. In: I.E.E.E Symposium, Tel-Aviv. March 1983

Analysis and Design. 2nd ed. Wiley; 1996

[14] Sabban A. Multiport network model

[15] Sabban A. Microstrip antenna arrays. U.S. Patent US 1986/4,623,893; 1986

[16] Sabban A. Wideband microstrip antenna arrays. I.E.E.E Antenna and Propagation Symposium MELCOM,

[17] Fujimoto K, James JR, editors. Mobile Antenna Systems Handbook. Boston, USA: Artech House; 1994

[18] Sabban A. New wideband notch antennas for communication systems.

[13] Balanis CA. Antenna Theory:

for evaluating radiation loss and coupling among discontinuities in microstrip circuits [PhD thesis]. University of Colorado at Boulder;

Sons; July 2016

*Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT…*

London; 1981

**39**(4):705-712

January 1991

Tel-Aviv; June 1981

Texas, USA. June 1983

[2] Valenta CR, Durgin GD. Harvesting wireless power: Survey of energyharvester conversion efficiency in farfield, wireless power transfer systems. IEEE Microwave Magazine. 2014;**15**(4):

[3] Nintanavongsa P, Muncuk U, Lewis DR, Chowdhury KR. Design optimization and implementation for RF energy harvesting circuits. IEEE Journal on Emerging and Selected Topics in Circuits and Systems. 2012;

[4] Devi KKA, Sadasivam S, Din NM, Chakrabarthy CK. Design of a 377 Ω patch antenna for ambient RF energy harvesting at downlink frequency of GSM 900. In: Proceedings of the 17th

Communications (APCC '11). Malaysia: Sabah; October 2011. pp. 492-495

[5] Rahim RA, Malek F, Anwar SFW, Hassan SLS, Junita MN, Hassan HF. A harmonic suppression circularly polarized patch antenna for an RF ambient energy harvesting system. In: Proceedings of the IEEE Conference on Clean Energy and Technology (CEAT '13). Malaysia: IEEE, Lankgkawi; November 2013. pp. 33-37

[6] Krakauskas M, Sabaawi AMA, Tsimenidis CC. Suspended patch microstrip antenna with cut rectangular slots for RF energy harvesting. In: Proceedings of the 10th Loughborough Antennas and Propagation Conference (LAPC '14). UK: Loughborough; November 2014. pp. 304-307

[7] Sabban A. Low Visibility Antennas for Communication Systems. USA: Taylor & Francis group; 2015

**33**

Asia Pacific Conference on

#### **Author details**

Albert Sabban1,2

1 Kinneret Academic College, Israel

2 Ort Braude College, Karmiel, Israel

\*Address all correspondence to: sabban@mx.kinneret.ac.il

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Wideband Passive and Active Wearable Energy Harvesting Systems for Medical and IOT… DOI: http://dx.doi.org/10.5772/intechopen.89699*

#### **References**

rectifying circuit, and a rechargeable battery. The harvesting energy system

system.

*Innovation in Global Green Technologies 2020*

**Author details**

Albert Sabban1,2

**32**

1 Kinneret Academic College, Israel

2 Ort Braude College, Karmiel, Israel

provided the original work is properly cited.

\*Address all correspondence to: sabban@mx.kinneret.ac.il

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

operates as a dual mode energy harvesting system. The low-noise amplifier is part of the receiving system. The LNA DC bias voltages are supplied by the receiving

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[2] Valenta CR, Durgin GD. Harvesting wireless power: Survey of energyharvester conversion efficiency in farfield, wireless power transfer systems. IEEE Microwave Magazine. 2014;**15**(4): 108-120

[3] Nintanavongsa P, Muncuk U, Lewis DR, Chowdhury KR. Design optimization and implementation for RF energy harvesting circuits. IEEE Journal on Emerging and Selected Topics in Circuits and Systems. 2012; **2**(1):24-33

[4] Devi KKA, Sadasivam S, Din NM, Chakrabarthy CK. Design of a 377 Ω patch antenna for ambient RF energy harvesting at downlink frequency of GSM 900. In: Proceedings of the 17th Asia Pacific Conference on Communications (APCC '11). Malaysia: Sabah; October 2011. pp. 492-495

[5] Rahim RA, Malek F, Anwar SFW, Hassan SLS, Junita MN, Hassan HF. A harmonic suppression circularly polarized patch antenna for an RF ambient energy harvesting system. In: Proceedings of the IEEE Conference on Clean Energy and Technology (CEAT '13). Malaysia: IEEE, Lankgkawi; November 2013. pp. 33-37

[6] Krakauskas M, Sabaawi AMA, Tsimenidis CC. Suspended patch microstrip antenna with cut rectangular slots for RF energy harvesting. In: Proceedings of the 10th Loughborough Antennas and Propagation Conference (LAPC '14). UK: Loughborough; November 2014. pp. 304-307

[7] Sabban A. Low Visibility Antennas for Communication Systems. USA: Taylor & Francis group; 2015

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[9] James JR, Hall PS, Wood C. Microstrip Antenna Theory and Design. London; 1981

[10] Sabban A, Gupta KC. Characterization of radiation loss from microstrip discontinuities using a multiport network modeling approach. IEEE Transactions on Microwave Theory and Techniques. April 1991; **39**(4):705-712

[11] Sabban A. A new wideband stacked microstrip antenna. In: IEEE Antenna and Propagation Symp., Houston, Texas, USA. June 1983

[12] Sabban A, Navon E. A MM-waves microstrip antenna array. In: I.E.E.E Symposium, Tel-Aviv. March 1983

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[16] Sabban A. Wideband microstrip antenna arrays. I.E.E.E Antenna and Propagation Symposium MELCOM, Tel-Aviv; June 1981

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Wireless Engineering and Technology

*Innovation in Global Green Technologies 2020*

Biomedical Engineering. April 2003;

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[28] Gupta B, Sankaralingam S, Dhar S.

implantable antennas in the last decade. In: Microwave Symposium (MMS), 2010 Mediterranean. 2010. pp. 251-267

Notaros BM, Mosig JR. Investigation and design of a multi-band wearable antenna. In: 3rd European Conference on Antennas and Propagation, EuCAP.

[30] Salonen P, Rahmat-Samii Y, Kivikoski M. Wearable antennas in the vicinity of human body. In: IEEE Antennas and Propagation Society International Symposium. Vol. 1. 2004.

[31] Kellomaki T, Heikkinen J,

reception. In: First European Conference on Antennas and Propagation, EuCAP. 2006. pp. 1-6

[32] Sabban A. Wideband printed antennas for medical applications. In: APMC 2009 Conference, Singapore.

radio propagation channels for ultrawideband body-centric wireless communication. IEEE Transactions on Antennas and Propagation. April 2009;

antenna for wireless body area networks. I.E.E.E. Transactions on Antennas and Propagation. Nov. 2006;

Kivikoski M. Wearable antennas for FM

[33] Alomainy A, Sani A, et al. Transient characteristics of wearable antennas and

[34] Klemm M, Troester G. Textile UWB

**50**(4):484-492

[19] Sabban A. Dual polarized dipole wearable antenna. U.S Patent number:

Journal. April 2016:75-82

8203497. USA, June 19, 2012

2012, July 2012

[20] Sabban A. Wideband tunable printed antennas for medical applications. In: IEEE Antenna and Propagation Symp., Chicago, IL, USA.

[21] Sabban A. New wideband printed antennas for medical applications. I.E.E.

[22] Sabban A. Comprehensive study of printed antennas on human body for medical applications. International Journal of Advance in Medical Science

[23] Kastner R, Heyman E, Sabban A. Spectral domain iterative analysis of single and double-layered microstrip antennas using the conjugate gradient algorithm. I.E.E.E Transactions on Antennas and Propagation. Sept. 1988;

[24] Sabban A. Microstrip antenna arrays. In: Nasimuddin N, editor. Microstrip Antennas. InTech; 2011. pp. 361-384. Available at: http://www. intechopen.com/articles/show/title/ microstrip-antenna-arrays. ISBN: 978-

[25] Sabban A. New wideband wearable notch antenna for energy harvesting applications. In: 12th European Conference on Antennas and Propagation EuCAP 2018, United

[26] Chirwa LC, Hammond PA, Roy S, Cumming DRS. Electromagnetic radiation from ingested sources in the human intestine between 150 MHz and

1.2 GHz. IEEE Transaction on

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(AMS). February 2013;**1**:1-10

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[36] ADS software. Agilent. Available at: http://www.home.agilent.com/agilent/ product.jspx?cc=IL&lc=eng&ckey= 1297113&nid=34346.0.00&id=1297113

**37**

**Chapter 3**

**Abstract**

automotive applications.

**1. Introduction**

of coupler's efficiency.

**Keywords:** PMMA, optical fiber, POF, WDM, network

The research in this chapter was carried out to optimize the efficiency of components and the entire system of Wavelength Division Multiplexing, WDM networking system based on Polymer Optical Fiber (POF). To achieve this purpose, a deeper analysis was performed on 1 × 3 POF coupler using fusion techniques in order to obtain and observe a number of parameters which directly affect the value

POF has many advantages compared to silica fiber and copper wires for short-

distance applications, such as low cost, easy installation and connection, the integration of low cost LED and so on. These advantages lead to a high demand on data transmission in various applications, especially regarding home-networking

and In-Vehicle Infotainment, or IVI's system on automotive field.

Coupler

Optimum Efficiency Analysis of

Ecofriendly WDM-POF Optical

*Hadi Guna, Mohammad Syuhaimi Ab-Rahman,* 

*Norhana Arsad, Roslan Shukor and Sahbudin Shaari*

This chapter was presented to promote the development of Wavelength Division Multiplexing, WDM networking system based on Polymer Optical Fiber (POF). 1 × 3 POF coupler has been fully utilized to couple the WDM optical signals*.* An optimum efficiency analysis and mathematical modeling has been conducted to produce an effective device to be integrated into WDM-POF system. But despite its high speed data transmission feature, optical fiber technology remains an expensive option in optical network, although the installation costs associated with fiber through the transmission network can be minimized through the fabrication of 1 × 3 POF coupler. The objective of this chapter is identifying the differences in factors affecting the output power of the POF 1 × 3 coupling. It is then able to develop an efficient WDM-POF network system with high output power at a minimal cost. Several measurements using a power meter record performance and analysis device losses and power outputs. The demultiplexer efficiency is approximately 70%. Demultiplexer fabrication is easy with color and epoxy filters, although for some parts it requires careful attention. The output shows that Ecofriendly WDM-POF Optical Coupler can be used as one of the low-cost media for home networking and

#### **Chapter 3**

## Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler

*Hadi Guna, Mohammad Syuhaimi Ab-Rahman, Norhana Arsad, Roslan Shukor and Sahbudin Shaari*

#### **Abstract**

This chapter was presented to promote the development of Wavelength Division Multiplexing, WDM networking system based on Polymer Optical Fiber (POF). 1 × 3 POF coupler has been fully utilized to couple the WDM optical signals*.* An optimum efficiency analysis and mathematical modeling has been conducted to produce an effective device to be integrated into WDM-POF system. But despite its high speed data transmission feature, optical fiber technology remains an expensive option in optical network, although the installation costs associated with fiber through the transmission network can be minimized through the fabrication of 1 × 3 POF coupler. The objective of this chapter is identifying the differences in factors affecting the output power of the POF 1 × 3 coupling. It is then able to develop an efficient WDM-POF network system with high output power at a minimal cost. Several measurements using a power meter record performance and analysis device losses and power outputs. The demultiplexer efficiency is approximately 70%. Demultiplexer fabrication is easy with color and epoxy filters, although for some parts it requires careful attention. The output shows that Ecofriendly WDM-POF Optical Coupler can be used as one of the low-cost media for home networking and automotive applications.

**Keywords:** PMMA, optical fiber, POF, WDM, network

#### **1. Introduction**

The research in this chapter was carried out to optimize the efficiency of components and the entire system of Wavelength Division Multiplexing, WDM networking system based on Polymer Optical Fiber (POF). To achieve this purpose, a deeper analysis was performed on 1 × 3 POF coupler using fusion techniques in order to obtain and observe a number of parameters which directly affect the value of coupler's efficiency.

POF has many advantages compared to silica fiber and copper wires for shortdistance applications, such as low cost, easy installation and connection, the integration of low cost LED and so on. These advantages lead to a high demand on data transmission in various applications, especially regarding home-networking and In-Vehicle Infotainment, or IVI's system on automotive field.

POF was initially used in automotive application for the first time in 1998 by Daimler-Chrysler. The development of optical data path is known as Domestic Digital Bus (D2B). Sensing is just one application area in automotive where photonics is used [1]. Typically, transport data path protocol so-called Media Oriented System Transport (MOST) with a speed of 24.8 Mbit/sec is used in many cars. However, this transmission data with Time Division Multiplexing (TDM)'s based network (as shown in **Figure 1**) has its own disadvantages where in the event of one or more malfunction lines (in the ring topology) will affect other line or more in MOST system.

In this analysis we aim to provide a better solution to a problem in the topology of ring bandwidth that many foreign carmakers use for the infotainment system of their network.

Laser can be very hazardous as best transmitting medium that can be used alongside GOF until the leakage taken place from the GOF body structure. A fiberreleased extremely high intensity light ray can potentially burn a human retinas and lead to a permanent blind. It was hard to imagine if this silica-based technology was put in place inside the vehicle where consumers used this data transmission services directly.

In the meantime, the combination of POF, which is very suitable for a lightemitting diode (LED) system, can be seen as the best solution to offer a more secure data communication network, not to mention the lowest cost we can get for initial and production costs. For applications such as machine or peripheral connections, control and monitoring, board interconnections and even domestic hi-fi systems, POF links are becoming increasingly popular. Unlike GOF, POF remains versatile with a large core diameter and low numerical aperture, resulting in a high capacity that they can bring along the fiber.

The '*ecofriendly*' area involves a rapidly changing group of methods and materials, ranging from energy generation techniques to non-toxic cleaning products. The general perception is that in recent decades the IT-revolution is bringing innovation and improvements to daily life of a similar scale. In these early stages, it is difficult to predict what may potentially constitute '*ecofriendly*' [2].

In the current world, IT-societies face an increasingly serious challenge: on the one hand, the multimedia-rich data transmitted travels at amazing speed, and on the other the total energy consumption of communication and networking devices and the resulting global CO2 emission are rising at an enormous rate. It is reported that currently, 3% of the world's energy is used by ICT, a system that generates roughly 2% of the world's CO2 emissions, equal to worldwide CO2 emissions by aircraft or a fifth of the world's CO2 emissions by vehicle [3].

**39**

*Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler*

According to Ericsson Media Relations' recent research survey, cost of energy account for roughly half the operating costs of a mobile operator.

Telecommunications technologies may therefore have a clear, tangible impact on reducing greenhouse gas emissions, power consumption, and effectively recycling

Therefore, finding solutions for optical communication's system that can greatly improve energy and resource efficiency not only helps the global environment, but also makes economic sense for telecom operators promoting viable and profitable business. Within the context for '*ecofriendly*' a range of paradigm shifting technical solutions can be anticipated, including but not limited to energyefficient network architecture & protocols, energy-efficient wireless transmission technologies (*e.g.* reduced transmission capacity & radiation), cross-layer synchronization strategies, and opportunistic spectrum exchange without creating

The Ecofriendly WDM-POF is provided on the basis of a network system consisting from POF. Ecofriendly WDM-POF is developed using a method that is environmentally friendly to divide and recombine a range of wavelengths. The Ethernet connection, DVD player and CCTV system was extensively used in three different wavelengths from ecologically friendly LED transmission systems. Red LED that is able to download and upload information over a 650 nm wavelength via Ethernet cable and green LED sends a video signal at a wavelength of 520 nm for DVD player while 470 nm LED will distribute the captured video using CCTV system. The Ecofriendly WDM-POF system will select a specific signal and produce it, if required. Special filter has been placed between the coupler and the receiving point. System and network performance are observed. In this chapter the product, production process, device and implementation strategy is focused on an environmentally sustainable solution for reducing energy usage and waste without impacting overall performance. The first documented approach in this paper is our

Taking care of the environment is a duty that everyone should feel responsible for. Most of us already know of environmentally friendly practices such as recycling to minimize pollution and reduce our carbon footprint. Most citizens, though, do not learn of new and upcoming technology that we can use to help reduce carbon emissions. Light-emitting diode (LED) lighting is a good example of this, which brings some environmental benefits. LED is a light source with a semiconductor that emits light when the current passes through it. Electrons, recombine with electron holes in the semiconductor, releasing energy in photon form. The color of the light (corresponding to the photons' energy) is determined by the energy that electrons need to reach the semiconductor's band gap. White light is generated on the semiconductor

device using several semiconductors or a film of light-emitting phosphorus.

LED lighting is up to 80% more effective than conventional lighting including fluorescent or incandescent lamps. 95% of energy is turned to light in LEDs and only 5% is lost as heat. This is contrasted to fluorescent lights that turn 95% of energy to heat and only 5% to light LED lights can have much less power than conventional lighting; a traditional 84 watt fluorescent can be replaced with a 36 watt LED that offers the same amount of illumination. Lower energy consumption reduces demand from power plants and lowers emissions of greenhouse gases. LED lights do not contain toxic materials. Many workplaces still use fluorescent strip lamps containing harmful chemicals like mercury. It contaminates the

*DOI: http://dx.doi.org/10.5772/intechopen.90510*

infrastructure waste [4].

dangerous inter-radiation [4].

Ecofriendly WDM-POF network implementation.

**2. The advantages of LED lights for the environment**

*Innovation in Global Green Technologies 2020*

that they can bring along the fiber.

to predict what may potentially constitute '*ecofriendly*' [2].

aircraft or a fifth of the world's CO2 emissions by vehicle [3].

*Sensor application using photonics in automotive area (source: hamamatsu.com).*

MOST system.

their network.

directly.

POF was initially used in automotive application for the first time in 1998 by Daimler-Chrysler. The development of optical data path is known as Domestic Digital Bus (D2B). Sensing is just one application area in automotive where photonics is used [1]. Typically, transport data path protocol so-called Media Oriented System Transport (MOST) with a speed of 24.8 Mbit/sec is used in many cars. However, this transmission data with Time Division Multiplexing (TDM)'s based network (as shown in **Figure 1**) has its own disadvantages where in the event of one or more malfunction lines (in the ring topology) will affect other line or more in

In this analysis we aim to provide a better solution to a problem in the topology of ring bandwidth that many foreign carmakers use for the infotainment system of

Laser can be very hazardous as best transmitting medium that can be used alongside GOF until the leakage taken place from the GOF body structure. A fiberreleased extremely high intensity light ray can potentially burn a human retinas and lead to a permanent blind. It was hard to imagine if this silica-based technology was put in place inside the vehicle where consumers used this data transmission services

In the meantime, the combination of POF, which is very suitable for a lightemitting diode (LED) system, can be seen as the best solution to offer a more secure data communication network, not to mention the lowest cost we can get for initial and production costs. For applications such as machine or peripheral connections, control and monitoring, board interconnections and even domestic hi-fi systems, POF links are becoming increasingly popular. Unlike GOF, POF remains versatile with a large core diameter and low numerical aperture, resulting in a high capacity

The '*ecofriendly*' area involves a rapidly changing group of methods and materials, ranging from energy generation techniques to non-toxic cleaning products. The general perception is that in recent decades the IT-revolution is bringing innovation and improvements to daily life of a similar scale. In these early stages, it is difficult

In the current world, IT-societies face an increasingly serious challenge: on the one hand, the multimedia-rich data transmitted travels at amazing speed, and on the other the total energy consumption of communication and networking devices and the resulting global CO2 emission are rising at an enormous rate. It is reported that currently, 3% of the world's energy is used by ICT, a system that generates roughly 2% of the world's CO2 emissions, equal to worldwide CO2 emissions by

**38**

**Figure 1.**

According to Ericsson Media Relations' recent research survey, cost of energy account for roughly half the operating costs of a mobile operator. Telecommunications technologies may therefore have a clear, tangible impact on reducing greenhouse gas emissions, power consumption, and effectively recycling infrastructure waste [4].

Therefore, finding solutions for optical communication's system that can greatly improve energy and resource efficiency not only helps the global environment, but also makes economic sense for telecom operators promoting viable and profitable business. Within the context for '*ecofriendly*' a range of paradigm shifting technical solutions can be anticipated, including but not limited to energyefficient network architecture & protocols, energy-efficient wireless transmission technologies (*e.g.* reduced transmission capacity & radiation), cross-layer synchronization strategies, and opportunistic spectrum exchange without creating dangerous inter-radiation [4].

The Ecofriendly WDM-POF is provided on the basis of a network system consisting from POF. Ecofriendly WDM-POF is developed using a method that is environmentally friendly to divide and recombine a range of wavelengths. The Ethernet connection, DVD player and CCTV system was extensively used in three different wavelengths from ecologically friendly LED transmission systems. Red LED that is able to download and upload information over a 650 nm wavelength via Ethernet cable and green LED sends a video signal at a wavelength of 520 nm for DVD player while 470 nm LED will distribute the captured video using CCTV system. The Ecofriendly WDM-POF system will select a specific signal and produce it, if required. Special filter has been placed between the coupler and the receiving point. System and network performance are observed. In this chapter the product, production process, device and implementation strategy is focused on an environmentally sustainable solution for reducing energy usage and waste without impacting overall performance. The first documented approach in this paper is our Ecofriendly WDM-POF network implementation.

#### **2. The advantages of LED lights for the environment**

Taking care of the environment is a duty that everyone should feel responsible for. Most of us already know of environmentally friendly practices such as recycling to minimize pollution and reduce our carbon footprint. Most citizens, though, do not learn of new and upcoming technology that we can use to help reduce carbon emissions. Light-emitting diode (LED) lighting is a good example of this, which brings some environmental benefits. LED is a light source with a semiconductor that emits light when the current passes through it. Electrons, recombine with electron holes in the semiconductor, releasing energy in photon form. The color of the light (corresponding to the photons' energy) is determined by the energy that electrons need to reach the semiconductor's band gap. White light is generated on the semiconductor device using several semiconductors or a film of light-emitting phosphorus.

LED lighting is up to 80% more effective than conventional lighting including fluorescent or incandescent lamps. 95% of energy is turned to light in LEDs and only 5% is lost as heat. This is contrasted to fluorescent lights that turn 95% of energy to heat and only 5% to light LED lights can have much less power than conventional lighting; a traditional 84 watt fluorescent can be replaced with a 36 watt LED that offers the same amount of illumination. Lower energy consumption reduces demand from power plants and lowers emissions of greenhouse gases.

LED lights do not contain toxic materials. Many workplaces still use fluorescent strip lamps containing harmful chemicals like mercury. It contaminates the atmosphere when disposed of in waste pits. Disposal needs to be managed via a certified waste carrier so that switching to LED reduces costs and time to enforcement–which helps protect the environment against further toxic waste.

LEDs have a better light transmission efficiency and focus light in one direction, compared to other types of light that waste energy in all directions, often illuminate areas where no light is needed (*e.g.* the ceiling). It needs fewer LED lights to achieve the same level of luminosity as fluorescent and incandescent lamps. Less lighting can reduce energy usage and thus benefit the environment.

A longer life span means lower production of carbon LED lights last up to six times longer than other lamp types, eliminating the regular maintenance demand. This leads to the use of fewer lamps and therefore fewer resources for production, processing and transport processes [5].

#### **3. A novel fused coupler**

A novel fused coupler and the special filter –an advanced design of WDM-POF network implementation, are two key elements of the WDM-POF system in this chapter. We suggest an innovative fusion technology that is simple and inexpensive to use with Bunsen burner and metal tube to produce indirect heating processes with low structural defects, low excess losses and a good splitting ratio in the production of POF-based coupler.

The term '*fusion*' typically describes the operation or method of liquefying and melting by applying heat. The fabrication approach varies notably from traditional biconical technique. Seeing that the fabrication of polymer fiber is not subject to very high temperatures, POF's are liquefied with yellow flame Bunsen burners (1000°C) indirect heat treatment rather than with an oxyhydrogen burner (heating temperatures T = 2660°C) applied conventionally to the production of GOF-based couplers [6, 7].

Metal tube is used to protect the POF structure from direct heater during the fiber fusion process of indirect heating. POFs which are vulnerable to severe damage in their core cause heating a bundle of POFs directly to the burner flame.

In the new method of fusion, as shown in **Figure 2**, fusion length *Lf*, twist *T* number, fusion time *tf*, pulling length *Lp* and other parameters are controllable parameters. The multimode step indexed POF with a core diameter of 1 mm of *Polymethylmethacrylate* (PMMA) was used as material for second-generation couplers. PMMA is one of the optical components most frequently used. The inherent absorption loss is mainly due to the stretching vibration of carbon hydrogen in PMMA core [7]. *Polyvinylchloride* (PVC) is another component used to cover the POF ports as a jacket.

The high cost of industrial coupler was posed as a crucial obstacle for the creation of wavelength division multiplexing (WDM), according to Kagami's 2006 Toyota R&D analysis report [8]. The fabrication process of expensive BFT device is considered a high production cost factor. The diameter of the fused taper area is extremely small by traditional BFT fabrication process, in which strain is accumulated and result in poor structural survivability.

Following the adaptation of the fused tapering technique for traditional multimode fiber, we successfully established the fabrication process for fused taper couplers with 1 × N POF. The handmade 1 × N coupler is an optical device that ends with *N* number of POF output terminals, while the other ends with one POF port. Like other traditional couplers, bidirectional operation is also possible, working from the *N* ports to 1 port (for coupling signal purposes) or vice versa (for splitting signals purposes). For instance, the optical 1 × 4 coupler formed by combining four *Polymethylmethacrylate* (PMMA) POF [9]. The output

**41**

**Figure 2.**

*Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler*

POF is designed and fabricated to fuse the tapered shape in some detail. **Figure 2**

*Fabrication process of* fused tapered *coupler: (a) configuration, (b) twisting and (c) fusion and (d) prototype* 

Standard multimode SI-POF is used with its core diameter of 980 μm, cladding thickness of 10 μm and the refractive index is 1.49. To obtain the results, demultiplexer is realized using handmade color films attached using epoxy resin to the edge of the connectors. The components are chosen because they are low cost and are

For applications like home networking, car industry, board interconnection, also residential hi-fi networks POF connectivity is increasingly prevalent. POF is versatile,

shows the process 1 × 4 POF coupler.

*of the 1 × 4 handmade coupler fabricated by fused tapering technique.*

easily found in the market [10].

**4. Ecofriendly WDM-POF**

*DOI: http://dx.doi.org/10.5772/intechopen.90510*

*Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler DOI: http://dx.doi.org/10.5772/intechopen.90510*

#### **Figure 2.**

*Innovation in Global Green Technologies 2020*

processing and transport processes [5].

**3. A novel fused coupler**

production of POF-based coupler.

POF ports as a jacket.

lated and result in poor structural survivability.

atmosphere when disposed of in waste pits. Disposal needs to be managed via a certified waste carrier so that switching to LED reduces costs and time to enforce-

LEDs have a better light transmission efficiency and focus light in one direction, compared to other types of light that waste energy in all directions, often illuminate areas where no light is needed (*e.g.* the ceiling). It needs fewer LED lights to achieve the same level of luminosity as fluorescent and incandescent lamps. Less lighting

A longer life span means lower production of carbon LED lights last up to six times longer than other lamp types, eliminating the regular maintenance demand. This leads to the use of fewer lamps and therefore fewer resources for production,

A novel fused coupler and the special filter –an advanced design of WDM-POF network implementation, are two key elements of the WDM-POF system in this chapter. We suggest an innovative fusion technology that is simple and inexpensive to use with Bunsen burner and metal tube to produce indirect heating processes with low structural defects, low excess losses and a good splitting ratio in the

The term '*fusion*' typically describes the operation or method of liquefying and melting by applying heat. The fabrication approach varies notably from traditional biconical technique. Seeing that the fabrication of polymer fiber is not subject to very high temperatures, POF's are liquefied with yellow flame Bunsen burners (1000°C) indirect heat treatment rather than with an oxyhydrogen burner (heating temperatures T = 2660°C) applied conventionally to the production of GOF-based couplers [6, 7]. Metal tube is used to protect the POF structure from direct heater during the fiber fusion process of indirect heating. POFs which are vulnerable to severe damage in their core cause heating a bundle of POFs directly to the burner flame. In the new method of fusion, as shown in **Figure 2**, fusion length *Lf*, twist *T* number, fusion time *tf*, pulling length *Lp* and other parameters are controllable parameters. The multimode step indexed POF with a core diameter of 1 mm of *Polymethylmethacrylate* (PMMA) was used as material for second-generation couplers. PMMA is one of the optical components most frequently used. The inherent absorption loss is mainly due to the stretching vibration of carbon hydrogen in PMMA core [7]. *Polyvinylchloride* (PVC) is another component used to cover the

The high cost of industrial coupler was posed as a crucial obstacle for the creation of wavelength division multiplexing (WDM), according to Kagami's 2006 Toyota R&D analysis report [8]. The fabrication process of expensive BFT device is considered a high production cost factor. The diameter of the fused taper area is extremely small by traditional BFT fabrication process, in which strain is accumu-

Following the adaptation of the fused tapering technique for traditional multimode fiber, we successfully established the fabrication process for fused taper couplers with 1 × N POF. The handmade 1 × N coupler is an optical device that ends with *N* number of POF output terminals, while the other ends with one POF port. Like other traditional couplers, bidirectional operation is also possible, working from the *N* ports to 1 port (for coupling signal purposes) or vice versa (for splitting signals purposes). For instance, the optical 1 × 4 coupler formed by combining four *Polymethylmethacrylate* (PMMA) POF [9]. The output

ment–which helps protect the environment against further toxic waste.

can reduce energy usage and thus benefit the environment.

**40**

*Fabrication process of* fused tapered *coupler: (a) configuration, (b) twisting and (c) fusion and (d) prototype of the 1 × 4 handmade coupler fabricated by fused tapering technique.*

POF is designed and fabricated to fuse the tapered shape in some detail. **Figure 2** shows the process 1 × 4 POF coupler.

Standard multimode SI-POF is used with its core diameter of 980 μm, cladding thickness of 10 μm and the refractive index is 1.49. To obtain the results, demultiplexer is realized using handmade color films attached using epoxy resin to the edge of the connectors. The components are chosen because they are low cost and are easily found in the market [10].

#### **4. Ecofriendly WDM-POF**

For applications like home networking, car industry, board interconnection, also residential hi-fi networks POF connectivity is increasingly prevalent. POF is versatile, as compared to GOF, with a wide core and a lower numerical aperture [1] and it can carry a high fiber capacity The optical coupler plays an important role among passive components for POF technologies, which is enabled by the versatility of a full product range. A POF coupler has been developed with various techniques. Thermal deformation, refining and merging, hand polished, scraping, etching, molding, reflecting body and biconic body are all common techniques have been applied in recent years [11].

In order to increase bandwidth to wavelength division multiplexing (WDM) in beginning topology, our current POF communication system enables data to be conveyed over more than one single wavelength. WDM is a system in which several signals are transmitted together in a multiplexed signal as separate wavelengths of light. As the **Figure 3** shows, WDM Multiplexer is the first active WDM-POF network designed to merge optical signals onto a single fiber from multiple singlewave end devices. If one of the signals (audio, video, Ethernet, *etc.*) breaks down, the network will not impact others if the primary transmission line is ineffective.

In WDM-POF system, many transmitters with different lights color to carry single information. For example, red light with 665 nm wavelength modulated with Ethernet signal while blue (λ1), green (λ2) and yellow (λ3) lights carry image information, RF and TV signal, respectively [7]. The Multiplexer (MUX) must couple the light and separate it by demultiplexer (DEMUX).

Due to its simple device approach for extending, WDM has extended over the past 20 years, the average bit rate of transmission into GOF-long-range systems: introducing another source of specific transmission wavelengths in combination with the MUX/DEMUX component directly increases the utilizable speed. The wavelengths for the WDM from 400 to 700 nm, as shown in **Figure 4**, are used because of the attenuation in POF.

By practice, the same device can also conduct the reverse of the same WDM methods, in which several wavelength information streams are split up into multiple single wavelength data flows. The reverse is termed de-multiplexing. Conceptually, as a single coupled signal, POF coupler has the same purpose, functions to couple or combine multiple optical data signals. Hence the design of POF couple-based WDM is feasible. A low-cost solution will be presented for POF-WDM system implementation.

Multiplexing the wavelength division has several advantages over the other approaches proposed to enhance a link's capacity:


#### **Figure 3.**

*Proposed design for WDM-POF network in star topology able to transmit three different signals: Ethernet (λ1), audio system (λ1) and CCTV (λ1) at the same time through one fiber.*

**43**

**Figure 4.**

*Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler*

3.*Is transparent*: does not rely on the protocol to be transmitted [2, 12]

4.If consumers need it, it is simple for network providers to add additional capacity in a few days. It offers WDM businesses an economic benefit. Part of a fiber can be leased to a consumer who gets quick access to networks without link to others. On the other side, the telecom company still has a separate part

5.*Is scalable*: a new channel can easily be added to existing channels instead of moving to a new technology. Companies only have to pay for the bandwidth

In the form of an effective transmission medium, a novel fused POF coupler is fabricated to split and recombine a range of wavelengths that represent different signals. Three separate wavelengths are used for the propagation of three specific networks sources: network link, infotainment network and video transmission system. With a 665 nm wavelength red LED capable of downloading and uploading information via Ethernet cable, while a 520 nm green LED could transmit a video image created from DVD player, and a 470 nm blue LED is an video transmission

The coupler and the receiver ends will be filtered with special interference so that the whole WDM system can select a single signal as needed. These solutions for interference filters are known for the visible spectrum and can be used not only in

To removed unnecessary signals and select the wavelength of the system as desired for the filter design. Other parameters will be observed, e.g., the effect of the filter position and the efficiency of the WDM-POF system, including optical

The color filters are made up of two types of plastic, almost the same as POF material About 65% of the line is made of polycarbonate plastic co-extruded. The remainder of the line is deep dyed polyester [15, 16]. By subtracting those color wavelengths, filters generate light. A red filter, therefore, absorbs blue and green so that only the red wavelengths can pass. The method is non-additive subtractive, so a full spectrum must be emitted by the light source. The swatch book provides detailed information about each filter's spectral energy curve. The curve defines the color wavelengths that each filter transmits. Supergel 342, for instance, transmits

output power, power loss, optical noise ratio and sensor crosstalk.

*Attenuation behavior of a POF in the area of the visible spectrum. (source: Gupta [2]).*

*DOI: http://dx.doi.org/10.5772/intechopen.90510*

of the network for other clients [12, 13]

network for CCTV system within the building.

the infrared.

they actually need [12, 14].

*Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler DOI: http://dx.doi.org/10.5772/intechopen.90510*

*Innovation in Global Green Technologies 2020*

as compared to GOF, with a wide core and a lower numerical aperture [1] and it can carry a high fiber capacity The optical coupler plays an important role among passive components for POF technologies, which is enabled by the versatility of a full product range. A POF coupler has been developed with various techniques. Thermal deformation, refining and merging, hand polished, scraping, etching, molding, reflecting body and biconic body are all common techniques have been applied in recent years [11]. In order to increase bandwidth to wavelength division multiplexing (WDM) in beginning topology, our current POF communication system enables data to be conveyed over more than one single wavelength. WDM is a system in which several signals are transmitted together in a multiplexed signal as separate wavelengths of light. As the **Figure 3** shows, WDM Multiplexer is the first active WDM-POF network designed to merge optical signals onto a single fiber from multiple singlewave end devices. If one of the signals (audio, video, Ethernet, *etc.*) breaks down, the network will not impact others if the primary transmission line is ineffective. In WDM-POF system, many transmitters with different lights color to carry single information. For example, red light with 665 nm wavelength modulated with Ethernet signal while blue (λ1), green (λ2) and yellow (λ3) lights carry image information, RF and TV signal, respectively [7]. The Multiplexer (MUX) must

Due to its simple device approach for extending, WDM has extended over the past 20 years, the average bit rate of transmission into GOF-long-range systems: introducing another source of specific transmission wavelengths in combination with the MUX/DEMUX component directly increases the utilizable speed. The wavelengths for the WDM from 400 to 700 nm, as shown in **Figure 4**, are used

By practice, the same device can also conduct the reverse of the same WDM methods, in which several wavelength information streams are split up into multiple single wavelength data flows. The reverse is termed de-multiplexing. Conceptually, as a single coupled signal, POF coupler has the same purpose, functions to couple or combine multiple optical data signals. Hence the design of POF couple-based WDM is feasible. A low-cost solution will be presented for POF-WDM system implementation. Multiplexing the wavelength division has several advantages over the other

*Proposed design for WDM-POF network in star topology able to transmit three different signals: Ethernet (λ1),* 

couple the light and separate it by demultiplexer (DEMUX).

because of the attenuation in POF.

approaches proposed to enhance a link's capacity:

1.Deals with appliances of low speed [12]

2.Works for existing single mode cable [12]

*audio system (λ1) and CCTV (λ1) at the same time through one fiber.*

**42**

**Figure 3.**

#### 3.*Is transparent*: does not rely on the protocol to be transmitted [2, 12]


In the form of an effective transmission medium, a novel fused POF coupler is fabricated to split and recombine a range of wavelengths that represent different signals. Three separate wavelengths are used for the propagation of three specific networks sources: network link, infotainment network and video transmission system. With a 665 nm wavelength red LED capable of downloading and uploading information via Ethernet cable, while a 520 nm green LED could transmit a video image created from DVD player, and a 470 nm blue LED is an video transmission network for CCTV system within the building.

The coupler and the receiver ends will be filtered with special interference so that the whole WDM system can select a single signal as needed. These solutions for interference filters are known for the visible spectrum and can be used not only in the infrared.

To removed unnecessary signals and select the wavelength of the system as desired for the filter design. Other parameters will be observed, e.g., the effect of the filter position and the efficiency of the WDM-POF system, including optical output power, power loss, optical noise ratio and sensor crosstalk.

The color filters are made up of two types of plastic, almost the same as POF material About 65% of the line is made of polycarbonate plastic co-extruded. The remainder of the line is deep dyed polyester [15, 16]. By subtracting those color wavelengths, filters generate light. A red filter, therefore, absorbs blue and green so that only the red wavelengths can pass. The method is non-additive subtractive, so a full spectrum must be emitted by the light source. The swatch book provides detailed information about each filter's spectral energy curve. The curve defines the color wavelengths that each filter transmits. Supergel 342, for instance, transmits

**Figure 4.** *Attenuation behavior of a POF in the area of the visible spectrum. (source: Gupta [2]).* about 40% of the blue and violet energy in the spectrum and 70% of the orange and red energy. In the yellow and green range, it absorbs all energy [15, 16].

In this analysis, several colors of red, blue and green filters are evaluated and selected for optimum experiment performance. By reading the curves of the spectral energy distribution (SED), the way the filter colors are selected. In the infrared range above 700 nm, filters that transmit high levels at 700 nm can also transmit high levels. The visible red light, for example, has a wavelength of around 665 nm. Red's filter color is chosen by which film offers the highest percentage of transmission and minimal loss. The same goes with choosing green and blue color filters. Eleven different colors were chosen for each red, green and blue filter in this experiment The goal is to observe which one of the options is better, showing maximum transmission and minimal losses.

The demultiplexer is produced by attaching the multimode POF at one end of the fiber with a connector. A small piece of color films are cut out and prepared for installation on the socket The glue used in this fabrication is epoxy resin, which consists of resin and hardener as mentioned before. When both the resin and the hardener are mixed a strong adhesive is produced that holds the components to be rigidly attached together. Using resin, the small piece of color film is then applied to the edge of the socket after polishing the end of the fiber connected to the socket. Instead, after applying the film on the resin to be applied to the socket, the part is then held tightly together for about 2 minutes to ensure that there is no gap between them and that a strong bond produced. This part has to be done carefully since it is important to avoid the epoxy resin coating the surface of the fiber as much as possible so that any power losses can be avoided when measuring. Nevertheless, since the socket edge is quite thin and sharp, it is not possible to avoid the spread of the epoxy resin to the fiber surface 100%.

After the adhesive is sealed, the POF is placed in a secure location so that the adhesive is not contaminated and is left to dry up. It usually takes nearly a day to completely set the resin. Upon curing of the epoxy, the film that attached to the end of the connector is cut in circle according to the shape of the socket's end. After the production process is carried out, the injection loss and energy consumption for each POF is measured and recorded. The power meter is the device used for reading. Most samples were produced in this test to get the best results and see which of the color filters showing the most transmission and providing the least losses. The POF's length is set at 3 meters long.

As shown in **Figure 5**, The test bed has been set up for 1 × 3 WDM-POF networks to calculate the performance of the handmade coupler-filter combination for the entire system. Red, green and blue LED transmitters inject each of the red filters and readings are taken accordingly. The same is done for the filters blue and red. It is found that measurements should be visible on the meter when calculation is performed with the power meter, otherwise the samples cannot be used to evaluate the characterization. Next, the POF with film must be attached to another short fiber using connector to calculate and obtain the readings. Then the other end of the short fiber to the power meter socket will be connected. The power meter comparison for red LED is set to-10.7 dBm, as is the case for blue and green LED. The other end of the POF (that without film) is attached to the transmitter before the readings can be taken. The LED is then inserted by the fiber and the injection loss rate and energy consumption is measured for each sample accordingly.

The transmitters carry a certain amount of information or data when each transmitter carries signals of different wavelengths defined by the LED. When filtering any other wavelength, the specially tailored color films are used. This requires only a photon to travel through the image and so transmits the data sent to the receiver. In **Figure 6** it is simple to understand filtering and signal coupling operation and **Figure 7** for the experiment of 1 × 2 POF-WDM system through a

**45**

**Figure 7.**

**Figure 5.**

**Figure 6.**

*signals.*

*Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler*

*Test bed for 3-channels WDM-POF system to transmit three different (ethernet, CCTV and DVD player)* 

*1 × 2 demultiplexer is used to split the signal to different frequency (color). The multiplexed signal is separated* 

*WDM-POF system design using 1 × 2 handmade coupler and filters.*

*according to the application (*e.g. *data & video signal) respectively.*

*DOI: http://dx.doi.org/10.5772/intechopen.90510*

*Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler DOI: http://dx.doi.org/10.5772/intechopen.90510*

#### **Figure 5.**

*Innovation in Global Green Technologies 2020*

maximum transmission and minimal losses.

POF's length is set at 3 meters long.

about 40% of the blue and violet energy in the spectrum and 70% of the orange and

In this analysis, several colors of red, blue and green filters are evaluated and selected for optimum experiment performance. By reading the curves of the spectral energy distribution (SED), the way the filter colors are selected. In the infrared range above 700 nm, filters that transmit high levels at 700 nm can also transmit high levels. The visible red light, for example, has a wavelength of around 665 nm. Red's filter color is chosen by which film offers the highest percentage of transmission and minimal loss. The same goes with choosing green and blue color filters. Eleven different colors were chosen for each red, green and blue filter in this experiment The goal is to observe which one of the options is better, showing

The demultiplexer is produced by attaching the multimode POF at one end of the fiber with a connector. A small piece of color films are cut out and prepared for installation on the socket The glue used in this fabrication is epoxy resin, which consists of resin and hardener as mentioned before. When both the resin and the hardener are mixed a strong adhesive is produced that holds the components to be rigidly attached together. Using resin, the small piece of color film is then applied to the edge of the socket after polishing the end of the fiber connected to the socket. Instead, after applying the film on the resin to be applied to the socket, the part is then held tightly together for about 2 minutes to ensure that there is no gap between them and that a strong bond produced. This part has to be done carefully since it is important to avoid the epoxy resin coating the surface of the fiber as much as possible so that any power losses can be avoided when measuring. Nevertheless, since the socket edge is quite thin and sharp, it

is not possible to avoid the spread of the epoxy resin to the fiber surface 100%.

After the adhesive is sealed, the POF is placed in a secure location so that the adhesive is not contaminated and is left to dry up. It usually takes nearly a day to completely set the resin. Upon curing of the epoxy, the film that attached to the end of the connector is cut in circle according to the shape of the socket's end. After the production process is carried out, the injection loss and energy consumption for each POF is measured and recorded. The power meter is the device used for reading. Most samples were produced in this test to get the best results and see which of the color filters showing the most transmission and providing the least losses. The

As shown in **Figure 5**, The test bed has been set up for 1 × 3 WDM-POF networks to calculate the performance of the handmade coupler-filter combination for the entire system. Red, green and blue LED transmitters inject each of the red filters and readings are taken accordingly. The same is done for the filters blue and red. It is found that measurements should be visible on the meter when calculation is performed with the power meter, otherwise the samples cannot be used to evaluate the characterization. Next, the POF with film must be attached to another short fiber using connector to calculate and obtain the readings. Then the other end of the short fiber to the power meter socket will be connected. The power meter comparison for red LED is set to-10.7 dBm, as is the case for blue and green LED. The other end of the POF (that without film) is attached to the transmitter before the readings can be taken. The LED is then inserted by the fiber and the injection loss rate and

The transmitters carry a certain amount of information or data when each transmitter carries signals of different wavelengths defined by the LED. When filtering any other wavelength, the specially tailored color films are used. This requires only a photon to travel through the image and so transmits the data sent to the receiver. In **Figure 6** it is simple to understand filtering and signal coupling operation and **Figure 7** for the experiment of 1 × 2 POF-WDM system through a

energy consumption is measured for each sample accordingly.

red energy. In the yellow and green range, it absorbs all energy [15, 16].

**44**

*Test bed for 3-channels WDM-POF system to transmit three different (ethernet, CCTV and DVD player) signals.*

#### **Figure 6.**

*WDM-POF system design using 1 × 2 handmade coupler and filters.*

#### **Figure 7.**

*1 × 2 demultiplexer is used to split the signal to different frequency (color). The multiplexed signal is separated according to the application (*e.g. *data & video signal) respectively.*

combination of red and green filter. **Figure 7** explained the activity when one of the source deactivated, the crosstalk between both fibers occurred affect the efficiency both transmission, red and green LED.

#### **5. Results**

The 1 × 3 coupler design plays an important role in combining three optical signals by the fused taper twisted component (see **Figure 2**) in which all three POFs fused and combined as so-called single POF. The fused tapered POFs should be manufactured and all bundled fibers fully fused. Otherwise, it would likely not be possible to pass on the signal led to a failure when combining the single signal numbers. [10, 17, 18].

Either during manufacturing processes or during characterization test stages the error may occur. Controlled heat anomalies during the fusion process become one of the major problems because it makes the core structure of POF more responsive to the heating process. When impaired, it becomes impossible or even difficult to let a light pass through the core To avoid micro-scaled cracks on core it's important to stop twisting and tightening POF. For that cause, if indirect heating is done through fiber, we use the metal tube to reduce the damage to the system.

The excessive deformation in the fused fiber bundle was reduced by indirect heating. It makes the fabrication of the fused-tapered fiber simpler and more effective. In particular, the constant processing capability ensures that fabrication time and productivity is minimized. This approach would significantly reduce the cost of making the coupler [6].

Bidirectional optical loss calculation was performed to investigate exactly the value of the energy intensity for each fused bundle POF output, whereby the red LED was inserted on both sides of the Fused Bundle independently through each POF input.

For both directions (left and right), the average optical loss for the fused POF bundle was measured and analytically compared. The analysis can be seen as shown in the **Figure 8**.

**Figure 8.** *Efficiency for fused bundle fibers from best to worst sample in both directions and the linear function of the 1 × N.*

**47**

**Figure 9.**

*Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler*

The finding above indicates that the optical loss in different directions for the fused bundle was not comparable. The fused POF bundle has an evaluation in the right direction of reduced optical loss. Therefore, it has been chosen as a POF coupler from the right side of the POF bundle because it can integrate multiple optical signals and produce an optical signal with decreased attenuation and greater efficiency than the other. Nevertheless, optical losses for the fused bundle are caused primarily by physical modification of the POF, especially of the Fused Taper. The improvement in the initial POF diameter resulted in a significant change in optical properties with the numerical aperture and maximum acceptance angle. All these improvements are based on the principle of spoil light propagation; there are more refracted beams of light and they are scattered out beyond the atmosphere [19]. In terms of market value, correlation of handmade and commercial couplers was

observed. The total cost of a 1 × 4 handmade POF coupler is less than 3 USD but not less than 250 USD for a commercial coupler available on the market. Currently, many devices are in use to couple a signal, such as a low-cost plastic optical fiber coupler from 1 × 2 acrylic-based [11]. Nevertheless, since the manufacturing processes were very difficult and costly, the handmade POF coupler can be considered

This research categorizes the optical loss as extrinsic loss because of the physical change of POF, LED projection to POF and the core-to-core connection end [3, 16]. The physical change in POFs caused by the fabrication process is observed to decrease by POFs in diameter to 1 mm and POFs have eventually fused into tapered form. Optical degradation may be caused by the direct LED projection to the POF surface when analysis takes place. In addition, the connection between the fused

The other factor which is critical in transmitting two separate wavelength signals on transmitters is the filter between the coupler and the receiver point. Two separate LEDs were used in this research, related to video signals (CCTV and DVD player); blue LEDs (470 nm) transmit DVD player images through fiber and green LEDs (570 nm) for CCTV, so that the high-quality video signals can be viewed on a

The filter itself has also been tested for its effectiveness. The correlation comes from both green and red LED output during the propagation of a different signal to be divided by a POF connector and the optical energy meter was placed directly

*(a) Power loss comparison between blue and green LED and (b) in linear function, green LED represent the* 

*video quality of the CCTV while blue LED represent the DVD player image quality.*

before the port of transmission of the transmitter, as shown in **Figure 9**.

tapered POF and the POF cable can cause optical loss [20].

*DOI: http://dx.doi.org/10.5772/intechopen.90510*

a potential solution to this issue.

monitor screen.

#### *Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler DOI: http://dx.doi.org/10.5772/intechopen.90510*

*Innovation in Global Green Technologies 2020*

both transmission, red and green LED.

**5. Results**

numbers. [10, 17, 18].

making the coupler [6].

POF input.

in the **Figure 8**.

combination of red and green filter. **Figure 7** explained the activity when one of the source deactivated, the crosstalk between both fibers occurred affect the efficiency

The 1 × 3 coupler design plays an important role in combining three optical signals by the fused taper twisted component (see **Figure 2**) in which all three POFs fused and combined as so-called single POF. The fused tapered POFs should be manufactured and all bundled fibers fully fused. Otherwise, it would likely not be possible to pass on the signal led to a failure when combining the single signal

Either during manufacturing processes or during characterization test stages the error may occur. Controlled heat anomalies during the fusion process become one of the major problems because it makes the core structure of POF more responsive to the heating process. When impaired, it becomes impossible or even difficult to let a light pass through the core To avoid micro-scaled cracks on core it's important to stop twisting and tightening POF. For that cause, if indirect heating is done through

The excessive deformation in the fused fiber bundle was reduced by indirect heating. It makes the fabrication of the fused-tapered fiber simpler and more effective. In particular, the constant processing capability ensures that fabrication time and productivity is minimized. This approach would significantly reduce the cost of

Bidirectional optical loss calculation was performed to investigate exactly the value of the energy intensity for each fused bundle POF output, whereby the red LED was inserted on both sides of the Fused Bundle independently through each

For both directions (left and right), the average optical loss for the fused POF bundle was measured and analytically compared. The analysis can be seen as shown

*Efficiency for fused bundle fibers from best to worst sample in both directions and the linear function* 

fiber, we use the metal tube to reduce the damage to the system.

**46**

**Figure 8.**

*of the 1 × N.*

The finding above indicates that the optical loss in different directions for the fused bundle was not comparable. The fused POF bundle has an evaluation in the right direction of reduced optical loss. Therefore, it has been chosen as a POF coupler from the right side of the POF bundle because it can integrate multiple optical signals and produce an optical signal with decreased attenuation and greater efficiency than the other. Nevertheless, optical losses for the fused bundle are caused primarily by physical modification of the POF, especially of the Fused Taper.

The improvement in the initial POF diameter resulted in a significant change in optical properties with the numerical aperture and maximum acceptance angle. All these improvements are based on the principle of spoil light propagation; there are more refracted beams of light and they are scattered out beyond the atmosphere [19].

In terms of market value, correlation of handmade and commercial couplers was observed. The total cost of a 1 × 4 handmade POF coupler is less than 3 USD but not less than 250 USD for a commercial coupler available on the market. Currently, many devices are in use to couple a signal, such as a low-cost plastic optical fiber coupler from 1 × 2 acrylic-based [11]. Nevertheless, since the manufacturing processes were very difficult and costly, the handmade POF coupler can be considered a potential solution to this issue.

This research categorizes the optical loss as extrinsic loss because of the physical change of POF, LED projection to POF and the core-to-core connection end [3, 16]. The physical change in POFs caused by the fabrication process is observed to decrease by POFs in diameter to 1 mm and POFs have eventually fused into tapered form. Optical degradation may be caused by the direct LED projection to the POF surface when analysis takes place. In addition, the connection between the fused tapered POF and the POF cable can cause optical loss [20].

The other factor which is critical in transmitting two separate wavelength signals on transmitters is the filter between the coupler and the receiver point. Two separate LEDs were used in this research, related to video signals (CCTV and DVD player); blue LEDs (470 nm) transmit DVD player images through fiber and green LEDs (570 nm) for CCTV, so that the high-quality video signals can be viewed on a monitor screen.

The filter itself has also been tested for its effectiveness. The correlation comes from both green and red LED output during the propagation of a different signal to be divided by a POF connector and the optical energy meter was placed directly before the port of transmission of the transmitter, as shown in **Figure 9**.

#### **Figure 9.**

*(a) Power loss comparison between blue and green LED and (b) in linear function, green LED represent the video quality of the CCTV while blue LED represent the DVD player image quality.*

The blue LED shows a higher loss as compared to the red LED in **Figure 9**. DVD images are highly sensitive to varying distances, the greater the distortion, the more the distortion resulted in the screen, the less performance of fiber data transfer.

The variations between the two signal rates were 3 dB and the performance of the video transmission system on the low-cost WDM-POF platform was increased. **Figure 10** demonstrates the video quality using the WDM-POF process.

Comparison for the optical line either using the filter or not, has been analyzed. The insertion loss of the cable with or without red filter is visualized in **Figure 11**, also with it logarithm and linear function of the data.

From the result, the insertion loss measured by the power meter is showing small loss rates when a film is attached to its socket when all the components are configured and red LED is injected. This also applies when injecting blue and green LEDs. We are taking red film A (filer labeled #4690) as the main filter for characterizing the same film using different sources and inject it with all three LEDs, red, green and blue. The results show a small increase in losses, compared to initial losses before the film is attached to the fiber, in the red-injected filter with a Redoutlet-transmitter. When the film is attached to the fiber it is the same for the power output. As **Figure 12** shows, an injection loss of 1 dB was reported right after the resin was inserted into the connector.

An increase of 5.3 μw of power output is observed. This is expected since the used of epoxy resin and the transmission limitation of the film gives the obtained data. However, different results are observed when blue and green LEDs are injected to the red filter. Small decrease of losses is observed when the fiber is attached with the film compared to before the fiber is attached with the film. The utilization of epoxy resin is ruled over by the higher transmission of green and blue transmitter through the particular red film. Above case happens when

**49**

**Figure 12.**

*with 665 nm wavelength.*

**Figure 11.**

*before and after connector glued by epoxy.*

*Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler*

the transmission percentage of the particular red film also shade or covers some

For characterization of same source injected through different filters, red LED is taken as the primary source. From the result, it is observed that sample 7 shows least losses and decrease of efficiency, while sample 3 shows the opposite. Since sample 3 being the one among the darkest film color meaning that only small or narrow transmission percentage of red LED or transmitter is allowed

*Effect on resin for demultiplexer filters approximately 1 dB insertion loss occurred on the measurement between* 

*Comparison between result from experimental and theory measured from red filter signal injected by red LED* 

*DOI: http://dx.doi.org/10.5772/intechopen.90510*

percentages of green and blue wavelength region.

#### **Figure 10.**

*Video quality of WDM-POF system of (a) 50 m, (b) 30 m, (c) 20 m and (d) 10 m of optical transmission line.*

#### *Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler DOI: http://dx.doi.org/10.5772/intechopen.90510*

the transmission percentage of the particular red film also shade or covers some percentages of green and blue wavelength region.

For characterization of same source injected through different filters, red LED is taken as the primary source. From the result, it is observed that sample 7 shows least losses and decrease of efficiency, while sample 3 shows the opposite. Since sample 3 being the one among the darkest film color meaning that only small or narrow transmission percentage of red LED or transmitter is allowed

#### **Figure 11.**

*Innovation in Global Green Technologies 2020*

resin was inserted into the connector.

transfer.

The blue LED shows a higher loss as compared to the red LED in **Figure 9**. DVD images are highly sensitive to varying distances, the greater the distortion, the more the distortion resulted in the screen, the less performance of fiber data

The variations between the two signal rates were 3 dB and the performance of the video transmission system on the low-cost WDM-POF platform was increased.

Comparison for the optical line either using the filter or not, has been analyzed. The insertion loss of the cable with or without red filter is visualized in **Figure 11**,

From the result, the insertion loss measured by the power meter is showing small loss rates when a film is attached to its socket when all the components are configured and red LED is injected. This also applies when injecting blue and green LEDs. We are taking red film A (filer labeled #4690) as the main filter for characterizing the same film using different sources and inject it with all three LEDs, red, green and blue. The results show a small increase in losses, compared to initial losses before the film is attached to the fiber, in the red-injected filter with a Redoutlet-transmitter. When the film is attached to the fiber it is the same for the power output. As **Figure 12** shows, an injection loss of 1 dB was reported right after the

An increase of 5.3 μw of power output is observed. This is expected since the used of epoxy resin and the transmission limitation of the film gives the obtained data. However, different results are observed when blue and green LEDs are injected to the red filter. Small decrease of losses is observed when the fiber is attached with the film compared to before the fiber is attached with the film. The utilization of epoxy resin is ruled over by the higher transmission of green and blue transmitter through the particular red film. Above case happens when

*Video quality of WDM-POF system of (a) 50 m, (b) 30 m, (c) 20 m and (d) 10 m of optical transmission line.*

**Figure 10** demonstrates the video quality using the WDM-POF process.

also with it logarithm and linear function of the data.

**48**

**Figure 10.**

*Effect on resin for demultiplexer filters approximately 1 dB insertion loss occurred on the measurement between before and after connector glued by epoxy.*

#### **Figure 12.**

*Comparison between result from experimental and theory measured from red filter signal injected by red LED with 665 nm wavelength.*

#### **Figure 13.**

*Comparison between result from experimental and theory measured from (a) green and (b) blue filter signal injected by red LED with 665 nm wavelength.*

**51**

*Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler*

lightweight color film permits the transmitting of red LED.

principle is the main idea for the demultiplexer model.

loss has been plotted in **Figure 14** below.

age deviation was the less fluctuating effect.

multiplexer and separated by demultiplexer.

**6. Conclusions**

polymer fiber.

to get through. The utilization of epoxy resin may also contributes to the deficiency of power output (efficiency) since the losses increase a lot for sample 3 apart from the reason it being a dark film with small percentage of transmission. On the other hand, the effect of efficiency of sample 7 is small because the larger percentage of transmission for red LED. According to the ROSCO SED Swatch Report. The predicted outcome can now be correlated with the expected signal from the color filter hypothesis, from the sample setup and the actual signal. The figure shows that on average less than 1 dB is the difference between experiments

The green and blue films technically are filtered out or block red LEDs due to a different wavelength spectrum of red transmitters that are released by various color films of different wavelengths, such as green and blue films. The red LED data analysis shown through green filters reveals that sample 1 blocks most transmission in areas with approximately 35 dB lower efficiency and the lowest loss among all samples (see **Figure 13a**). The same applies to blue filters, which mostly block the red LED transmission (see **Figure 13b**). The lighter color films (green and blue) the smaller the output, in this case red LED, with various wavelength sources. The

Contrast the red filters with green filters and the blue ones, block some red LEDs as it is clear that the film can only be crossed by red wavelengths (т = 665 nm). The film blocks any other propagation not within the spectrum of the wavelength. This

Furthermore, combination of working function between LED sources and color filter plays an important role in WDM-POF system. Some samples each attached with three different color filter (blue, green and red filter) has been injected with three different sources (blue, green and red LED) and the graph of each insertion

See **Figure 14** above, all data have more variations directly after light hit the filter via fiber as blue filter was inserted by all three optical sources blue green and red color. Likewise, all light sources will fluctuate the data transmission capacity except the blue LED. This fluctuation was caused by the SED percentage of each filter and by the intensity of each light source. The greater light source strength was transmitted by the more fluctuating graph and the less significant of SED percent-

To summarize, the idea of a single channel or wavelength for POF is extended before the WDM definition is introduced, which results in a restriction of bandwidth. By increasing the bandwidth of the Ecofriendly WDM-POF solves this problem. The theory of WDM indicates efficiency, which in short-distance communication has become the alternative. An optical division was made using multimode SI-POF type with 1 mm core size based on POF technology. The coupler was developed through fabrication and characterization stages. A technology was also employed to develop a short-haul communication demultiplexer based on optical

This experiment shows multiple signals received via a single fiber of different wavelengths. This model was based on the principle of multiplexer and demultiplexer. The system uses just three wavelengths: blue (λ1 = 430 nm), green (λ2 = 570 nm), and red (λ3 = 665 nm) to transmit the transmission components as well as demultiplexer filters. The red, green and blue light source are mixed by

*DOI: http://dx.doi.org/10.5772/intechopen.90510*

and theory.

#### **Figure 14.**

*Effect on combination of working function between optical sources and filters, whereas all three filters (red, green and blue) were injected by light source (a) λ1 = 470 nm, (b) λ2 = 520 nm and (c) λ3 = 665 nm.*

#### *Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler DOI: http://dx.doi.org/10.5772/intechopen.90510*

to get through. The utilization of epoxy resin may also contributes to the deficiency of power output (efficiency) since the losses increase a lot for sample 3 apart from the reason it being a dark film with small percentage of transmission. On the other hand, the effect of efficiency of sample 7 is small because the larger percentage of transmission for red LED. According to the ROSCO SED Swatch Report. The predicted outcome can now be correlated with the expected signal from the color filter hypothesis, from the sample setup and the actual signal. The figure shows that on average less than 1 dB is the difference between experiments and theory.

The green and blue films technically are filtered out or block red LEDs due to a different wavelength spectrum of red transmitters that are released by various color films of different wavelengths, such as green and blue films. The red LED data analysis shown through green filters reveals that sample 1 blocks most transmission in areas with approximately 35 dB lower efficiency and the lowest loss among all samples (see **Figure 13a**). The same applies to blue filters, which mostly block the red LED transmission (see **Figure 13b**). The lighter color films (green and blue) the smaller the output, in this case red LED, with various wavelength sources. The lightweight color film permits the transmitting of red LED.

Contrast the red filters with green filters and the blue ones, block some red LEDs as it is clear that the film can only be crossed by red wavelengths (т = 665 nm). The film blocks any other propagation not within the spectrum of the wavelength. This principle is the main idea for the demultiplexer model.

Furthermore, combination of working function between LED sources and color filter plays an important role in WDM-POF system. Some samples each attached with three different color filter (blue, green and red filter) has been injected with three different sources (blue, green and red LED) and the graph of each insertion loss has been plotted in **Figure 14** below.

See **Figure 14** above, all data have more variations directly after light hit the filter via fiber as blue filter was inserted by all three optical sources blue green and red color. Likewise, all light sources will fluctuate the data transmission capacity except the blue LED. This fluctuation was caused by the SED percentage of each filter and by the intensity of each light source. The greater light source strength was transmitted by the more fluctuating graph and the less significant of SED percentage deviation was the less fluctuating effect.

#### **6. Conclusions**

*Innovation in Global Green Technologies 2020*

*injected by red LED with 665 nm wavelength.*

**50**

**Figure 14.**

**Figure 13.**

*Effect on combination of working function between optical sources and filters, whereas all three filters (red, green and blue) were injected by light source (a) λ1 = 470 nm, (b) λ2 = 520 nm and (c) λ3 = 665 nm.*

*Comparison between result from experimental and theory measured from (a) green and (b) blue filter signal* 

To summarize, the idea of a single channel or wavelength for POF is extended before the WDM definition is introduced, which results in a restriction of bandwidth. By increasing the bandwidth of the Ecofriendly WDM-POF solves this problem. The theory of WDM indicates efficiency, which in short-distance communication has become the alternative. An optical division was made using multimode SI-POF type with 1 mm core size based on POF technology. The coupler was developed through fabrication and characterization stages. A technology was also employed to develop a short-haul communication demultiplexer based on optical polymer fiber.

This experiment shows multiple signals received via a single fiber of different wavelengths. This model was based on the principle of multiplexer and demultiplexer. The system uses just three wavelengths: blue (λ1 = 430 nm), green (λ2 = 570 nm), and red (λ3 = 665 nm) to transmit the transmission components as well as demultiplexer filters. The red, green and blue light source are mixed by multiplexer and separated by demultiplexer.

Filters play a key role in giving Ecofriendly WDM-POF device a greater insertion loss, but because of the filter's color band gap, the internet speed is always constant and the video image resolution is quite good, the performance of a range of output ports has not been badly damaged. Several parameters have been noted, such as optical output power and energy losses on the devices and not to mention the impact of filter placement and efficacy of the handmade 1 × N Ecofriendly WDM-POF coupler.

For characterizing analysis the power level of the demultiplexer has been studied in red LEDs with a 665 nm wavelength inserted into various color filters. Analysis shows that filters of the same wavelength as the transmitter retain performance when other wavelength ranges are either filtered out or blocked This main concept is fully utilized for the designing of demultiplexer for short-haul applications. Final analysis indicates that filter efficiency can exceed 70%. Performance enhancement can be accomplished through practical means. Although the integration device exhibits very high transmitting attenuation, it has been tested for the sending of audio, DVD player and CCTV images data, using this method of handmade Ecofriendly WDM-POF coupler.

The results show that Ecofriendly WDM-POF coupler can be used as a costeffective wavelength multiplexer, as it can combine different wavelengths with main advantages that are low optical loss and inexpensive. An extensive experiment to enhance the homogeneity of this model was proposed. Nevertheless, fusion methodology with certain drawbacks has no uniformity in fabricating Ecofriendly WDM-POF coupler, as POF coupler with good performance could hardly be manufactured reliably. With experience and practice, this Ecofriendly WDM-POF system can be enhanced. The Ecofriendly WDM-POF system is very preferred because it is not as pricey as other consumer POF coupler. In addition, the production and deployment process is simple, quick and suitable for implementation for short distance communication.

#### **Acknowledgements**

This research has been conducted in Computer& Network Security Laboratory, Universiti Kebangsaan Malaysia (UKM). This project is supported by Ministry of Science, technology and Environment, Government of Malaysia, 01-01-02-SF0493 and Linear Dms Solutions Sdn Bhd, DIP-2018-017. All of the handmade fabrication method of POF coupler, 1 × N handmade™-POF coupler and also the low cost WDM-POF network solution were protected by patent numbered PI2010700001.

**53**

**Author details**

and Sahbudin Shaari

Hadi Guna\*, Mohammad Syuhaimi Ab-Rahman, Norhana Arsad, Roslan Shukor

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Universiti Kebangsaan Malaysia, Selangor Darul Ehsan, Malaysia

\*Address all correspondence to: hadi\_guna87@yahoo.com

provided the original work is properly cited.

*Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler*

*DOI: http://dx.doi.org/10.5772/intechopen.90510*

*Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler DOI: http://dx.doi.org/10.5772/intechopen.90510*

*Innovation in Global Green Technologies 2020*

Ecofriendly WDM-POF coupler.

distance communication.

**Acknowledgements**

numbered PI2010700001.

POF coupler.

Filters play a key role in giving Ecofriendly WDM-POF device a greater insertion loss, but because of the filter's color band gap, the internet speed is always constant and the video image resolution is quite good, the performance of a range of output ports has not been badly damaged. Several parameters have been noted, such as optical output power and energy losses on the devices and not to mention the impact of filter placement and efficacy of the handmade 1 × N Ecofriendly WDM-

For characterizing analysis the power level of the demultiplexer has been studied in red LEDs with a 665 nm wavelength inserted into various color filters. Analysis shows that filters of the same wavelength as the transmitter retain performance when other wavelength ranges are either filtered out or blocked This main concept is fully utilized for the designing of demultiplexer for short-haul applications. Final analysis indicates that filter efficiency can exceed 70%. Performance enhancement can be accomplished through practical means. Although the integration device exhibits very high transmitting attenuation, it has been tested for the sending of audio, DVD player and CCTV images data, using this method of handmade

The results show that Ecofriendly WDM-POF coupler can be used as a costeffective wavelength multiplexer, as it can combine different wavelengths with main advantages that are low optical loss and inexpensive. An extensive experiment to enhance the homogeneity of this model was proposed. Nevertheless, fusion methodology with certain drawbacks has no uniformity in fabricating Ecofriendly WDM-POF coupler, as POF coupler with good performance could hardly be manufactured reliably. With experience and practice, this Ecofriendly WDM-POF system can be enhanced. The Ecofriendly WDM-POF system is very preferred because it is not as pricey as other consumer POF coupler. In addition, the production and deployment process is simple, quick and suitable for implementation for short

This research has been conducted in Computer& Network Security Laboratory, Universiti Kebangsaan Malaysia (UKM). This project is supported by Ministry of Science, technology and Environment, Government of Malaysia, 01-01-02-SF0493 and Linear Dms Solutions Sdn Bhd, DIP-2018-017. All of the handmade fabrication method of POF coupler, 1 × N handmade™-POF coupler and also the low cost WDM-POF network solution were protected by patent

**52**

#### **Author details**

Hadi Guna\*, Mohammad Syuhaimi Ab-Rahman, Norhana Arsad, Roslan Shukor and Sahbudin Shaari Universiti Kebangsaan Malaysia, Selangor Darul Ehsan, Malaysia

\*Address all correspondence to: hadi\_guna87@yahoo.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

### **References**

[1] KK, HP, Photodetectors for LiDAR. Hamamatsu Corporation; 2019. p. 20

[2] Gupta SC. Textbook on Optical Fiber Communication and Its Applications. 3rd ed. New Delhi: PHI Learning Pvt. Ltd; 2018

[3] Janota A, Hrbček J. Slovak ETC system implemented–what next? In: Mikulski J, editor. Transport Systems Telematics. Berlin Heidelberg: Springer; 2011. pp. 30-37

[4] Ericsson Green Power to Bring Mobile Telephony to Billions of People. 2008

[5] Schubert EF et al. Solid-State Lighting- : A Benevolent Technology. Vol. 69. Bristol: ROYAUME-UNI: Institute of Physics; 2006. p. 31

[6] Jeong Y, Bae S, Oh K. All fiber N × N fused tapered plastic optical fiber (POF) power splitters for photodynamic therapy applications. Current Applied Physics. 2009;**9**(4, Supplement 1): e273-e275

[7] Imoto K et al. New biconically tapered fiber star coupler fabricated by indirect heating method. Journal of Lightwave Technology. 1987;**5**(5):694-699

[8] Kagami, M., Visible Optical Fiber Communication, in Special Issue: Visible Optical Fiber Communication. Japan: R&D Review of Toyota CRDL; 2005;**40**(2):1-6

[9] Ab-Rahman MS, Guna H, Harun MH. 1xN self-made polymer optical fiber based splitter for POF-650nm-LED based application. In: 2009 International Conference on Electrical Engineering and Informatics. Selangor, Malaysia; 2009

[10] Ab-Rahman MS et al. Fabrikasi dan Pencirian Pencerai Optik 1×12

Buatan Tangan Berasaskan Gentian Optik Polimer Diperbuat daripada Polimetil Metakrilat. Sains Malaysiana. 2010;**39**(3):459-466

[11] Ehsan AA, Shaari S, Ab-Rahman MS. Low cost 1x2 acrylicbased plastic optical fiber coupler with hollow taper waveguide. In: 25TH of Progress in Electromagnetics Research Symposium. Beijing, China: Progress in Electromagnetics Research Symposium, PIERS; 2009

[12] Gumaste A, Antony T. DWDM Network Designs and Engineering Solutions. USA: Cisco Press; 2003

[13] Bischoff D. Wavelength Multiplexing: WDM and DWDM Systems. Essay. 2009. pp. 1-27

[14] Gupta P, Khurana H. Public entrepreneurship: A dynamic strength for budding green technology. In: Proceedings of the 4th National Conference; INDIACom-2010. New Delhi; 2010

[15] Rosco, Roscolux, Harbor View Avenue. Stamford: Rosco Laboratories; 2003

[16] Rosco. In: Rosco, editor. ROSCOLUX Color Filter. Stamford: Rosco: Harbor View Avenue; 2003. pp. 1-2

[17] Ab-Rahman MS et al. In: Yasin M, Harun SW, Arof H, editors. Integration of Eco-Friendly POF Based Splitter and Optical Filter for Low-Cost WDM Network Solutions. Optical Fiber Communications and Devices. London: InTech; February 2012. p. 380

[18] Ab-Rahman MS et al. A novel star topology POF-WDM system. In: Business, Engineering and Industrial Applications (ISBEIA), 2011 IEEE Symposium on 2011; 2011

**55**

*Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler*

*DOI: http://dx.doi.org/10.5772/intechopen.90510*

[19] Held G. Fiber-Optic and Satellite Communications in Understanding Data Communications. USA: New Riders

[20] Appajaiah A, Kretzschmar HJ, Daum W. Aging behavior of

polymer optical fibers: Degradation characterization by FTIR. Journal of Applied Polymer Science.

Publishing; 2010

2007;**103**(2):860-870

*Optimum Efficiency Analysis of Ecofriendly WDM-POF Optical Coupler DOI: http://dx.doi.org/10.5772/intechopen.90510*

[19] Held G. Fiber-Optic and Satellite Communications in Understanding Data Communications. USA: New Riders Publishing; 2010

[20] Appajaiah A, Kretzschmar HJ, Daum W. Aging behavior of polymer optical fibers: Degradation characterization by FTIR. Journal of Applied Polymer Science. 2007;**103**(2):860-870

**54**

*Innovation in Global Green Technologies 2020*

[1] KK, HP, Photodetectors for LiDAR. Hamamatsu Corporation; 2019. p. 20

Buatan Tangan Berasaskan Gentian Optik Polimer Diperbuat daripada Polimetil Metakrilat. Sains Malaysiana.

[12] Gumaste A, Antony T. DWDM Network Designs and Engineering Solutions. USA: Cisco Press; 2003

[13] Bischoff D. Wavelength Multiplexing: WDM and DWDM Systems. Essay. 2009. pp. 1-27

[14] Gupta P, Khurana H. Public entrepreneurship: A dynamic strength for budding green technology. In: Proceedings of the 4th National Conference; INDIACom-2010. New

[15] Rosco, Roscolux, Harbor View Avenue. Stamford: Rosco Laboratories;

View Avenue; 2003. pp. 1-2

InTech; February 2012. p. 380

Symposium on 2011; 2011

[18] Ab-Rahman MS et al. A novel star topology POF-WDM system. In: Business, Engineering and Industrial Applications (ISBEIA), 2011 IEEE

[16] Rosco. In: Rosco, editor. ROSCOLUX Color Filter. Stamford: Rosco: Harbor

[17] Ab-Rahman MS et al. In: Yasin M, Harun SW, Arof H, editors. Integration of Eco-Friendly POF Based Splitter and Optical Filter for Low-Cost WDM Network Solutions. Optical Fiber Communications and Devices. London:

2010;**39**(3):459-466

PIERS; 2009

Delhi; 2010

2003

[11] Ehsan AA, Shaari S, Ab-Rahman MS. Low cost 1x2 acrylicbased plastic optical fiber coupler with hollow taper waveguide. In: 25TH of Progress in Electromagnetics Research Symposium. Beijing, China: Progress in Electromagnetics Research Symposium,

[2] Gupta SC. Textbook on Optical Fiber Communication and Its Applications. 3rd ed. New Delhi: PHI Learning Pvt.

[3] Janota A, Hrbček J. Slovak ETC system implemented–what next? In: Mikulski J, editor. Transport Systems Telematics. Berlin Heidelberg: Springer;

[4] Ericsson Green Power to Bring Mobile Telephony to Billions of People.

[5] Schubert EF et al. Solid-State Lighting- : A Benevolent Technology. Vol. 69. Bristol: ROYAUME-UNI: Institute of Physics; 2006. p. 31

[6] Jeong Y, Bae S, Oh K. All fiber N × N fused tapered plastic optical fiber (POF) power splitters for photodynamic therapy applications. Current Applied Physics. 2009;**9**(4, Supplement 1):

[7] Imoto K et al. New biconically tapered fiber star coupler fabricated by indirect heating method. Journal of Lightwave Technology. 1987;**5**(5):694-699

[8] Kagami, M., Visible Optical Fiber Communication, in Special Issue: Visible Optical Fiber Communication. Japan: R&D Review of Toyota CRDL;

[9] Ab-Rahman MS, Guna H, Harun MH. 1xN self-made polymer optical fiber based splitter for POF-650nm-LED based application. In: 2009 International Conference on Electrical Engineering and Informatics. Selangor,

[10] Ab-Rahman MS et al. Fabrikasi dan Pencirian Pencerai Optik 1×12

Ltd; 2018

**References**

2011. pp. 30-37

2008

e273-e275

2005;**40**(2):1-6

Malaysia; 2009

**Chapter 4**

**Abstract**

drying time

**57**

**1. Introduction**

Study on Designing and

Generator Used in Drying

Pump Dryer in Drying of

*Nguyen Hay, Le Anh Duc and Pham Van Kien*

*Ganoderma lucidum*

Technology and Efficiency of

Manufacturing a Radio-Frequency

a Radio Frequency-Assisted Heat

A radio-frequency (RF) generator applied in drying technology was designed and manufactured for drying *Ganoderma lucidum*. The drying experiments were conducted by drying method of RF-assisted heat pump in order to inspect the operating parameters of the RF generator and investigate the effects of the input

**Keywords:** *Ganoderma lucidum*, heat pump, radio frequency, drying temperature,

Drying is a common and effective preservation technique that reduces moisture content of material to lower levels required. Therefore, drying can minimize the spoilage of various microbes in material and the physical, chemical, and biochemical changes within the drying products thereby increasing overall shelf life by considerable periods of time. However, the drying process will affect the quality of

drying parameters on drying rate in the RF-assisted heat pump drying of *Ganoderma lucidum*. The results have shown that the RF generator achieved the required operating parameters as design such as RF power of 3 kW and operating frequency of 27 MHz. In RF-assisted heat pump drying, increase in RF power and drying air temperature increases the drying rate. Meanwhile, drying air velocity does not significantly affect the drying rate. At RF power of 1.95 kW, the drying time reduces by 9, 17, and 33% in comparison with RF power of 1.3, 0.65, and 0 kW (heat pump drying). At drying air temperature of 50°C, the drying time reduces by 10% and 21% in comparison with drying air temperature of 40 and 45°C. Besides, increasing RF power retains the higher content of polysaccharide in *Ganoderma lucidum*, and the *Ganoderma lucidum* samples retain the color better after drying.

#### **Chapter 4**

Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying Technology and Efficiency of a Radio Frequency-Assisted Heat Pump Dryer in Drying of *Ganoderma lucidum*

*Nguyen Hay, Le Anh Duc and Pham Van Kien*

#### **Abstract**

A radio-frequency (RF) generator applied in drying technology was designed and manufactured for drying *Ganoderma lucidum*. The drying experiments were conducted by drying method of RF-assisted heat pump in order to inspect the operating parameters of the RF generator and investigate the effects of the input drying parameters on drying rate in the RF-assisted heat pump drying of *Ganoderma lucidum*. The results have shown that the RF generator achieved the required operating parameters as design such as RF power of 3 kW and operating frequency of 27 MHz. In RF-assisted heat pump drying, increase in RF power and drying air temperature increases the drying rate. Meanwhile, drying air velocity does not significantly affect the drying rate. At RF power of 1.95 kW, the drying time reduces by 9, 17, and 33% in comparison with RF power of 1.3, 0.65, and 0 kW (heat pump drying). At drying air temperature of 50°C, the drying time reduces by 10% and 21% in comparison with drying air temperature of 40 and 45°C. Besides, increasing RF power retains the higher content of polysaccharide in *Ganoderma lucidum*, and the *Ganoderma lucidum* samples retain the color better after drying.

**Keywords:** *Ganoderma lucidum*, heat pump, radio frequency, drying temperature, drying time

#### **1. Introduction**

Drying is a common and effective preservation technique that reduces moisture content of material to lower levels required. Therefore, drying can minimize the spoilage of various microbes in material and the physical, chemical, and biochemical changes within the drying products thereby increasing overall shelf life by considerable periods of time. However, the drying process will affect the quality of the product such as nutritional standards, sensory standards, and physical and chemical standards. Therefore, the drying method and drying parameters should be considered to find a suitable drying method with optimum drying condition to retain a high quality of drying products, especially in food technology, agricultural products, and medicinal products.

and manufacture a RF generator applied in drying technology for drying

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying…*

*Ganoderma lucidum* in RF-assisted heat pump drying process.

**2. Researching object and method**

*DOI: http://dx.doi.org/10.5772/intechopen.88825*

**2.1 Researching object**

(see **Table 1**).

**2.2 Researching methods**

*2.2.1 Designing and calculating method*

and oscillator circuit of RF generator.

*2.2.2 Manufacture of RF generator method*

and purchased in the market.

*Physical thermal index of the drying material.*

**Table 1.**

**59**

*Ganoderma lucidum*, in which RF-assisted heat pump drying method is applied, and (2) to investigate the effects of the input drying parameters as drying air temperature, drying air velocity and RF power on the drying rate, and the quality of

A RF generator applied in drying technology is designed and manufactured in order to achieve a required maximum RF power of 3 kW and frequency of 27 MHz. *Ganoderma lucidum* used for the experiments is red *Ganoderma lucidum* (*Ganoderma boninense*). After being harvested, *Ganoderma lucidum* has a moisture content of 3 (d.b) (i.e., 75% (w.b)), diameter of 12 cm, thickness of 1.5 cm, and glossy red brown color. *Ganoderma lucidum* samples are cleaned with dry tissues. The initial moisture content of the material is determined by a moisture analyzer

• The required RF power is calculated based on physical and thermal properties of *Ganoderma lucidum* and theory of designing and calculating drying system.

The components of RF generator are manufactured in a single unit as designed and installed to complete a RF operator. Some standard components are selected

**No Symbol Value** 1 Gb 20 kg/batch 2 *mLC* 20 kg 3 ω<sup>i</sup> 75% (w.b) 4 ω<sup>f</sup> 13% (w.b) 5 Cp 3.613 kJ/(kg °C) 6 r 3150 kJ/kg 7 ti 30°C 8 tf 45°C

• The circuit diagram and the components of the RF generator are designed and manufactured based on theory of RF heating mechanism, heat exchanger,

*Ganoderma lucidum* is a medicinal product that contains various bioactive ingredients. Polysaccharide is a main bioactive ingredient in *Ganoderma lucidum* which has been found to be medically active in several therapeutic effects such as antitumor, anti-inflammatory, antiviral, anticancer, and anti-HIV [1]. However, polysaccharide and other bioactive ingredients in *Ganoderma lucidum* are heat sensitive and the high drying temperature tends to cause higher loss of active ingredients in dehydrated *Ganoderma lucidum*. Therefore, in drying *Ganoderma lucidum*, drying method as well as drying parameters should be considered carefully.

RF technology has shown some unique advantages in drying technology. RF heating is a volumetric heating method, which provides fast and deeper heat generation within material that increases heating rate and shortens drying time significantly. RF heating mechanism is described in **Figure 1**. In which, the RF generator creates an alternating electric field between two electrodes. The material is placed between the electrodes. The wet molecules within material continuously reorient themselves to face opposite poles of the alternating electric field. The friction resulting from the rotational movement of the molecules and the space-charge displacement causes the material to rapidly heat throughout its mass.

There were numerous studies of RF drying technology in which RF is combined with other drying methods as convection drying using hot air and freeze-drying for drying food and agricultural products [2–9]. The results show that heat generation within the whole volume of drying material that supports the heat transfer and moisture diffusion process to take place faster shortens the drying time and the temperature, and moisture distribution within material becomes more uniform. The drying products still retain their characteristic color and taste.

In heat pump drying with circulating drying air, drying air after being blown through the heat pump has the specific temperature, velocity, and humidity. Drying air will be blown into the drying chamber, and the drying process is performed here. In heat pump drying, the drying air temperature is at low level. So, the drying products can retain a high content of bioactive ingredients and their characteristic color and taste.

The drying technology using RF and heat pump drying has been found to be suitable for drying medicinal products. The objectives of this study are (1) to design

**Figure 1.** *RF heating mechanism.*

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying… DOI: http://dx.doi.org/10.5772/intechopen.88825*

and manufacture a RF generator applied in drying technology for drying *Ganoderma lucidum*, in which RF-assisted heat pump drying method is applied, and (2) to investigate the effects of the input drying parameters as drying air temperature, drying air velocity and RF power on the drying rate, and the quality of *Ganoderma lucidum* in RF-assisted heat pump drying process.

#### **2. Researching object and method**

#### **2.1 Researching object**

the product such as nutritional standards, sensory standards, and physical and chemical standards. Therefore, the drying method and drying parameters should be considered to find a suitable drying method with optimum drying condition to retain a high quality of drying products, especially in food technology, agricultural

displacement causes the material to rapidly heat throughout its mass.

The drying products still retain their characteristic color and taste.

There were numerous studies of RF drying technology in which RF is combined with other drying methods as convection drying using hot air and freeze-drying for drying food and agricultural products [2–9]. The results show that heat generation within the whole volume of drying material that supports the heat transfer and moisture diffusion process to take place faster shortens the drying time and the temperature, and moisture distribution within material becomes more uniform.

In heat pump drying with circulating drying air, drying air after being blown through the heat pump has the specific temperature, velocity, and humidity. Drying air will be blown into the drying chamber, and the drying process is performed here. In heat pump drying, the drying air temperature is at low level. So, the drying products can retain a high content of bioactive ingredients and their characteristic

The drying technology using RF and heat pump drying has been found to be suitable for drying medicinal products. The objectives of this study are (1) to design

*Ganoderma lucidum* is a medicinal product that contains various bioactive ingredients. Polysaccharide is a main bioactive ingredient in *Ganoderma lucidum* which has been found to be medically active in several therapeutic effects such as antitumor, anti-inflammatory, antiviral, anticancer, and anti-HIV [1]. However, polysaccharide and other bioactive ingredients in *Ganoderma lucidum* are heat sensitive and the high drying temperature tends to cause higher loss of active ingredients in dehydrated *Ganoderma lucidum*. Therefore, in drying *Ganoderma lucidum*, drying method as well as drying parameters should be considered carefully. RF technology has shown some unique advantages in drying technology. RF heating is a volumetric heating method, which provides fast and deeper heat generation within material that increases heating rate and shortens drying time significantly. RF heating mechanism is described in **Figure 1**. In which, the RF generator creates an alternating electric field between two electrodes. The material is placed between the electrodes. The wet molecules within material continuously reorient themselves to face opposite poles of the alternating electric field. The friction resulting from the rotational movement of the molecules and the space-charge

products, and medicinal products.

*Innovation in Global Green Technologies 2020*

color and taste.

**Figure 1.**

**58**

*RF heating mechanism.*

A RF generator applied in drying technology is designed and manufactured in order to achieve a required maximum RF power of 3 kW and frequency of 27 MHz.

*Ganoderma lucidum* used for the experiments is red *Ganoderma lucidum* (*Ganoderma boninense*). After being harvested, *Ganoderma lucidum* has a moisture content of 3 (d.b) (i.e., 75% (w.b)), diameter of 12 cm, thickness of 1.5 cm, and glossy red brown color. *Ganoderma lucidum* samples are cleaned with dry tissues. The initial moisture content of the material is determined by a moisture analyzer (see **Table 1**).

#### **2.2 Researching methods**

#### *2.2.1 Designing and calculating method*


#### *2.2.2 Manufacture of RF generator method*

The components of RF generator are manufactured in a single unit as designed and installed to complete a RF operator. Some standard components are selected and purchased in the market.


**Table 1.** *Physical thermal index of the drying material.*

#### *2.2.3 Measurement method*

The parameters can be measured by specialized measuring instruments directly such as temperature, velocity of drying air, voltage, and electric current. The other parameters are determined by the exchange formulas.

*q*<sup>1</sup> ¼ *mLC:Cp: t <sup>f</sup>* � *ti*

*DOI: http://dx.doi.org/10.5772/intechopen.88825*

ture of 45°C is 35 minutes. The heat required is calculated as

*<sup>Q</sup>*<sup>1</sup> <sup>¼</sup> *<sup>q</sup>*<sup>1</sup> *τ*1

vaporized water in the material and latent heat of drying material.

*3.1.2 The heat required for vaporizing water in the material*

The mass of vaporized water in the material (kg) is

1 � *ω <sup>f</sup>*

*<sup>Q</sup>*<sup>2</sup> <sup>¼</sup> *<sup>q</sup>*<sup>2</sup> *τ*2

**No Name Description**

1 Colorimeter Type: Minolta CR-200

2 Frequency measurement instrument Type: Acoustimeter CAT #A139

3 High-voltage voltmeter Type: Voltmeter-MDP-50 K

4 Amperemeter Type: Amperemeter-C.A401

6 Moisture analyzer Type: DBS 60–3 model

7 Electronic scale digital balance Type: DS-2002-N

5 Thermal sensor Type: AYN-MF59-104F-3950FB-1000

*GW* <sup>¼</sup> *mLC: <sup>ω</sup><sup>i</sup>* � *<sup>ω</sup> <sup>f</sup>*

7 hours. The heat required is calculated as

So,

**Table 2.**

**61**

*Parameter index of the measurements.*

<sup>¼</sup> <sup>20</sup> � <sup>3</sup>*:*<sup>613</sup> � ð Þ¼ <sup>45</sup> � <sup>30</sup> <sup>1084</sup> *kJ* (2)

<sup>35</sup> � <sup>60</sup> <sup>¼</sup> <sup>0</sup>*:*516*kW* (3)

<sup>1</sup> � <sup>0</sup>*:*<sup>13</sup> <sup>¼</sup> <sup>14</sup>*:*<sup>25</sup> *kg* (4)

<sup>7</sup> � <sup>3600</sup> <sup>¼</sup> <sup>1</sup>*:*<sup>782</sup> *kW* (6)

Max frequency: 70 � 0.01 MHz

Voltage range resolution: 0.5–10 kVAC �5%

Ampere range resolution: 0.1–10 A � 1%

Measurement ranges: �60–300°C � 0.05°C

Repeatability (sd) with 2 g sample: 0.15% Moisture value predicted: 0–100%

Max weighing capacity of 2000 � 0.001 grams

Maximum capacity: 60 g � 0.01% Temperature range: 50–200°C Temperature increments: 1°C

The predictive time period required for *Ganoderma lucidum* to get the tempera-

In the drying process, an amount of heat must be supplied to vaporize the water within drying material at specific drying temperature in order that the material achieves the required final moisture. The heat required depends on the mass of

<sup>¼</sup> <sup>20</sup>*:*ð Þ <sup>0</sup>*:*<sup>75</sup> � <sup>0</sup>*:*<sup>13</sup>

The initial moisture content of *Ganoderma lucidum* is 75%. The predictive time period required for *Ganoderma lucidum* to get the final moisture content of 13% is

<sup>¼</sup> <sup>44896</sup>

*q*<sup>2</sup> ¼ *GW:r* ¼ 14*:*25 � 3150 ¼ 44896 *kJ* (5)

<sup>¼</sup> <sup>1084</sup>

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying…*

#### *2.2.4 Method of experiment*

Experiments for investigation of the effects of the input drying parameters on drying rate in the RF-assisted heat pump drying of *Ganoderma lucidum* are conducted at the drying air temperature of 40, 45, and 50°C; drying air velocity of 1.2, 1.6, and 2.0 m/s; and RF power of 0.65, 1.3, and 1.95 kW.

#### *2.2.5 Method of determining moisture content*

The *Ganoderma lucidum* weight measurements are taken regularly after intervals of 20 minutes by an electronic scale digital balance (see **Table 1**). Each experiment is conducted until the drying material achieves the moisture content of 0.15 (d.b) (i.e., 13% (w.b)) and completed in triplicates.

The color of the drying products is measured by a colorimeter (see **Table 1**). The colorimeter displays three reflected light intensities corresponding to the lab color values. The total change in color of the drying *Ganoderma lucidum* sample with reference to the original sample is calculated as

$$
\Delta E^\* = \sqrt{\left(L\_0 - L^\*\right)^2 + \left(a\_0 - a^\*\right)^2 + \left(b\_0 - b^\*\right)^2} \tag{1}
$$

The parameters in Eq. (1) are described in detail in part of 3.4.2 c. (3.4.2 c. Color of drying material).

Polysaccharide content of *Ganoderma lucidum* is determined by highperformance liquid chromatography (HPLC) method.

Statistical parameters such as mean and standard deviation are used to solve the experiment data. Examining the differences of the statistical data is conducted by means of least significant difference (LSD).

#### **3. Results and discussions**

#### **3.1 The RF power of RF generator**

The heat required for drying process was calculated based on the theory of calculating and designing drying system [10].

Physical and thermal property index of the drying material (*Ganoderma lucidum*) is given in **Table 2**.

#### *3.1.1 The heat required for heating the material*

The heat required for heating the material in drying process is the heat of heating the drying material until the material achieves the required temperature. The required temperature of 45°C is chosen for calculation:

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying… DOI: http://dx.doi.org/10.5772/intechopen.88825*

$$q\_1 = m\_{LC}C\_p.(t\_f - t\_i) = 20 \times 3.613 \times (45 - 30) = 1084 \text{ kJ} \tag{2}$$

The predictive time period required for *Ganoderma lucidum* to get the temperature of 45°C is 35 minutes. The heat required is calculated as

$$Q\_1 = \frac{q\_1}{\tau\_1} = \frac{1084}{35 \times 60} = 0.516 \, kW \tag{3}$$

#### *3.1.2 The heat required for vaporizing water in the material*

In the drying process, an amount of heat must be supplied to vaporize the water within drying material at specific drying temperature in order that the material achieves the required final moisture. The heat required depends on the mass of vaporized water in the material and latent heat of drying material.

The mass of vaporized water in the material (kg) is

$$\text{G}\_W = \frac{\mathfrak{m}\_{LC} \cdot \left(\alpha\_i - \alpha\_f\right)}{\mathbf{1} - \alpha\_f} = \frac{20.(0.75 - 0.13)}{\mathbf{1} - 0.13} = \mathbf{14.25 kg} \tag{4}$$

So,

*2.2.3 Measurement method*

*Innovation in Global Green Technologies 2020*

*2.2.4 Method of experiment*

parameters are determined by the exchange formulas.

The parameters can be measured by specialized measuring instruments directly such as temperature, velocity of drying air, voltage, and electric current. The other

Experiments for investigation of the effects of the input drying parameters on

conducted at the drying air temperature of 40, 45, and 50°C; drying air velocity of

The *Ganoderma lucidum* weight measurements are taken regularly after intervals of 20 minutes by an electronic scale digital balance (see **Table 1**). Each experiment is conducted until the drying material achieves the moisture content of 0.15 (d.b)

The color of the drying products is measured by a colorimeter (see **Table 1**). The colorimeter displays three reflected light intensities corresponding to the lab color values. The total change in color of the drying *Ganoderma lucidum* sample with

The parameters in Eq. (1) are described in detail in part of 3.4.2 c. (3.4.2 c. Color

Statistical parameters such as mean and standard deviation are used to solve the experiment data. Examining the differences of the statistical data is conducted by

The heat required for drying process was calculated based on the theory of

Physical and thermal property index of the drying material (*Ganoderma*

The heat required for heating the material in drying process is the heat of heating the drying material until the material achieves the required temperature.

Polysaccharide content of *Ganoderma lucidum* is determined by high-

ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi *<sup>L</sup>*<sup>0</sup> � *<sup>L</sup>*<sup>∗</sup> ð Þ<sup>2</sup> <sup>þ</sup> *<sup>a</sup>*<sup>0</sup> � *<sup>a</sup>*<sup>∗</sup> ð Þ<sup>2</sup> <sup>þ</sup> *<sup>b</sup>*<sup>0</sup> � *<sup>b</sup>*<sup>∗</sup> ð Þ<sup>2</sup>

(1)

drying rate in the RF-assisted heat pump drying of *Ganoderma lucidum* are

1.2, 1.6, and 2.0 m/s; and RF power of 0.65, 1.3, and 1.95 kW.

*2.2.5 Method of determining moisture content*

(i.e., 13% (w.b)) and completed in triplicates.

reference to the original sample is calculated as

q

performance liquid chromatography (HPLC) method.

*<sup>Δ</sup>E*<sup>∗</sup> <sup>¼</sup>

means of least significant difference (LSD).

calculating and designing drying system [10].

*3.1.1 The heat required for heating the material*

The required temperature of 45°C is chosen for calculation:

**3. Results and discussions**

*lucidum*) is given in **Table 2**.

**60**

**3.1 The RF power of RF generator**

of drying material).

$$q\_2 = G\_W.r = 14.25 \times 3150 = 44896 \text{ kJ} \tag{5}$$

The initial moisture content of *Ganoderma lucidum* is 75%. The predictive time period required for *Ganoderma lucidum* to get the final moisture content of 13% is 7 hours. The heat required is calculated as


$$Q\_2 = \frac{q\_2}{\tau\_2} = \frac{44896}{7 \times 3600} = 1.782 \text{ kW} \tag{6}$$

**Table 2.** *Parameter index of the measurements.*

#### *3.1.3 The heat loss for heating the drying tray*

In the drying process, the drying material is placed on a drying tray which is normally a plastic mesh grid. So, there must be an amount of heat loss for heating the drying tray until the drying tray gets the drying air temperature:

$$q\_3 = m\_{\text{tray}}.C\_{\text{PVC}}.\left(t\_f - t\_i\right) = \text{25.05 kJ} \tag{7}$$

in which mch (30 kg), *t*

*DOI: http://dx.doi.org/10.5772/intechopen.88825*

*ch*

software, the surrounding area of a top is*Ft* <sup>¼</sup> <sup>1</sup>*:*<sup>62</sup> *<sup>m</sup>*2.

*<sup>Q</sup>*<sup>6</sup> <sup>¼</sup> *<sup>q</sup>*5*:<sup>F</sup>* <sup>¼</sup> *k tch*

So, the area of the drying chamber is

The radiation heat loss is calculated as

*<sup>Q</sup>*<sup>7</sup> <sup>¼</sup> *<sup>ε</sup>:F:Co: <sup>T</sup> <sup>f</sup>*

radiation ratio of absolute black object, *<sup>C</sup>*<sup>0</sup> <sup>¼</sup> <sup>5</sup>*:*67*W<sup>=</sup> <sup>m</sup>*<sup>2</sup>*:K*<sup>4</sup> � �. Thus, the total heat required for drying process is

Therefore, the RF power of RF generator is chosen P = 3 kW.

The heat loss is calculated as

*3.1.7 Radiation heat loss*

required for RF generator is.

**63**

*3.1.6 The heat loss through the drying chamber wall*

chamber wall (Fw) and two tops (Ft). The area of the drying chamber wall is

specific heat of galvanized steel, Cp\_steel = 0.49 kJ/(kg °C).

<sup>1</sup> (30°C), and *t*

*ch*

The inside wall of drying chamber is in contact with drying air, and the outside wall is in contact with the environment. This causes the heat loss through the drying chamber wall in the drying process, and it depends on the material and area of the drying chamber. The area of the drying chamber (F) includes the area of the drying

*Fw* <sup>¼</sup> <sup>2</sup>*: <sup>l</sup>*<sup>ð</sup> *ch:hch* <sup>þ</sup> *wch:hch*Þ ¼ <sup>2</sup> � <sup>ð</sup>1*:*<sup>25</sup> � <sup>0</sup>*:*<sup>75</sup> <sup>þ</sup> <sup>1</sup>*:*<sup>15</sup> � <sup>0</sup>*:*75Þ ¼ <sup>3</sup>*:*<sup>6</sup> *<sup>m</sup>*<sup>2</sup> (13)

*<sup>F</sup>* <sup>¼</sup> *Fw* <sup>þ</sup> <sup>2</sup>*:Ft* <sup>¼</sup> 6, 847 *<sup>m</sup>*<sup>2</sup> (14)

*outside* � �*:<sup>F</sup>* <sup>¼</sup> <sup>0</sup>*:*<sup>212</sup> *kW* (15)

<sup>100</sup> � �<sup>4</sup> " # <sup>¼</sup> <sup>0</sup>*:*<sup>593</sup> *kW* (16)

QRF ¼ Q1 þ Q2 þ Q3 ¼ 2*:*307 kW (18)

C).

After expanding the top of the drying chamber on computer by AutoCAD

*inside* � *t ch*

in which k is thermal conductivity of galvanized steel and k is 2.06 W/(m.<sup>o</sup>

lch, wch, and hch are the length, the width, and the height of the drying chamber.

� *Ti*

Qtotal ¼ Q1 þ Q2 þ Q3 þ Q4 þ Q5 þ Q6 þ Q7 ¼ 3*:*632 kW (17)

In current study, the RF operator will be designed, manufactured, and applied in RF-assisted heat pump drying. So, in the drying process, RF heating has the main function of heating the material, vaporizing water within the material, and heating the drying tray. The other heat losses are supplied by heat pump. Thus, the heat

<sup>100</sup> � �<sup>4</sup>

in which ε is the radiation ratio of galvanized steel, ε = 0.85, and C0 is the

initial temperature, and final temperature of the drying chamber and Cp\_steel is

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying…*

<sup>2</sup> (45°C) are mass of drying chamber,

in which mtray is the mass of the tray, mtray = 1 kg, and CP\_plastic is the specific heat capacity of plastic, CP\_plastic = 1.67 kJ/(kg °C).

The predictive time period required for the drying tray to get the temperature of 45°C is 45 minutes. The heat loss is calculated as

$$Q\_3 = \frac{q\_3}{\tau\_3} = \frac{25.05}{45 \times 60} = 0.009 \text{ kW} \tag{8}$$

#### *3.1.4 Heat loss through pipes*

In the drying process, the drying air flows inside a pipe system, and the outside wall of the pipe is in contact with environment. So, the heat loss through pipes should be considered, and it depends on the pipe material, size, length of the pipe, and drying temperature. The pipe is normally made of PVC plastic.

The length of pipe from the pump to the drying chamber is 1.5 m, so the surface area of the pipe is

$$S\_0 = \pi .d\_2 l = \mathbf{3.14} \times \mathbf{0.2} \times \mathbf{1.5} = \mathbf{0.942} \, m^2 \tag{9}$$

So, the heat loss through pipes is calculated as

$$Q\_4 = \mathcal{S}\_o \cdot q\_4 = \mathcal{S}\_o \cdot \lambda\_{PVC} \cdot \left(t\_f^v - t\_i^v\right) \cdot \frac{2.\pi}{\ln\frac{4}{d\_1}} = 0.374 \, kW \tag{10}$$

in which *t v <sup>i</sup>* (30°C), *t v <sup>f</sup>* (45°C), d1 (0.193 m), d2 (0.2 m), and *λPVC*(*λPVC* = 0.15 W/ (m °C)) are temperature of the outside wall and inside wall, internal diameter, external diameter of the pipe, and thermal conductivity of PVC plastic.

#### *3.1.5 Heat loss for heating the drying chamber*

The drying process is performed in a drying chamber that is also heated up to the drying temperature. So, the heat loss for heating the drying chamber should be considered, and it depends on the material and mass of the chamber and drying temperature. In drying process of food and agricultural products, the drying chamber is normally made of a galvanized steel for food hygiene:

$$q\_{\xi} = m\_{ch} \mathcal{C}\_{\text{steel}} \left( t\_f^{ch} - t\_i^{ch} \right) = \mathbf{30} \times \mathbf{0}.49 \times (45 - 30) = 220.5 \,\text{kJ} \tag{11}$$

The predictive time period required for the drying chamber to get the temperature of 45°C is 25 minutes. The heat loss is calculated as

$$Q\_{\\$} = \frac{q\_{\\$}}{\tau\_{\\$}} = \frac{220.5}{25 \times 60} = 0.147 \, kW \tag{12}$$

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying… DOI: http://dx.doi.org/10.5772/intechopen.88825*

in which mch (30 kg), *t ch* <sup>1</sup> (30°C), and *t ch* <sup>2</sup> (45°C) are mass of drying chamber, initial temperature, and final temperature of the drying chamber and Cp\_steel is specific heat of galvanized steel, Cp\_steel = 0.49 kJ/(kg °C).

#### *3.1.6 The heat loss through the drying chamber wall*

*3.1.3 The heat loss for heating the drying tray*

*Innovation in Global Green Technologies 2020*

heat capacity of plastic, CP\_plastic = 1.67 kJ/(kg °C).

45°C is 45 minutes. The heat loss is calculated as

*3.1.4 Heat loss through pipes*

area of the pipe is

in which *t*

**62**

*v*

*<sup>i</sup>* (30°C), *t*

*q*<sup>5</sup> ¼ *mch:Csteel: t*

*<sup>Q</sup>*<sup>3</sup> <sup>¼</sup> *<sup>q</sup>*<sup>3</sup> *τ*3

and drying temperature. The pipe is normally made of PVC plastic.

So, the heat loss through pipes is calculated as

*v*

*3.1.5 Heat loss for heating the drying chamber*

*Q*<sup>4</sup> ¼ *So:q*<sup>4</sup> ¼ *So:λPVC: t*

ber is normally made of a galvanized steel for food hygiene:

*ch <sup>f</sup>* � *t ch i* 

ture of 45°C is 25 minutes. The heat loss is calculated as

*<sup>Q</sup>*<sup>5</sup> <sup>¼</sup> *<sup>q</sup>*<sup>5</sup> *τ*5

In the drying process, the drying material is placed on a drying tray which is normally a plastic mesh grid. So, there must be an amount of heat loss for heating

in which mtray is the mass of the tray, mtray = 1 kg, and CP\_plastic is the specific

<sup>¼</sup> <sup>25</sup>*:*<sup>05</sup>

The predictive time period required for the drying tray to get the temperature of

In the drying process, the drying air flows inside a pipe system, and the outside wall of the pipe is in contact with environment. So, the heat loss through pipes should be considered, and it depends on the pipe material, size, length of the pipe,

The length of pipe from the pump to the drying chamber is 1.5 m, so the surface

*v <sup>f</sup>* � *t v i* 

(m °C)) are temperature of the outside wall and inside wall, internal diameter,

drying temperature. So, the heat loss for heating the drying chamber should be considered, and it depends on the material and mass of the chamber and drying temperature. In drying process of food and agricultural products, the drying cham-

The drying process is performed in a drying chamber that is also heated up to the

The predictive time period required for the drying chamber to get the tempera-

<sup>¼</sup> <sup>220</sup>*:*<sup>5</sup>

external diameter of the pipe, and thermal conductivity of PVC plastic.

*<sup>S</sup>*<sup>0</sup> <sup>¼</sup> *<sup>π</sup>:d*2*:<sup>l</sup>* <sup>¼</sup> <sup>3</sup>*:*<sup>14</sup> � <sup>0</sup>*:*<sup>2</sup> � <sup>1</sup>*:*<sup>5</sup> <sup>¼</sup> <sup>0</sup>*:*<sup>942</sup> *<sup>m</sup>*<sup>2</sup> (9)

*<sup>f</sup>* (45°C), d1 (0.193 m), d2 (0.2 m), and *λPVC*(*λPVC* = 0.15 W/

¼ 30 � 0*:*49 � ð Þ¼ 45 � 30 220*:*5 *kJ* (11)

<sup>25</sup> � <sup>60</sup> <sup>¼</sup> <sup>0</sup>*:*<sup>147</sup> *kW* (12)

*:* 2*:π* ln *<sup>d</sup> d*1

<sup>¼</sup> <sup>25</sup>*:*<sup>05</sup> *kJ* (7)

<sup>45</sup> � <sup>60</sup> <sup>¼</sup> <sup>0</sup>*:*<sup>009</sup> *kW* (8)

¼ 0*:*374 *kW* (10)

the drying tray until the drying tray gets the drying air temperature:

*q*<sup>3</sup> ¼ *mtray:CPVC: t <sup>f</sup>* � *ti*

The inside wall of drying chamber is in contact with drying air, and the outside wall is in contact with the environment. This causes the heat loss through the drying chamber wall in the drying process, and it depends on the material and area of the drying chamber. The area of the drying chamber (F) includes the area of the drying chamber wall (Fw) and two tops (Ft).

The area of the drying chamber wall is

$$F\_w = \mathcal{Z} \left( l\_{ch} h\_{ch} + w\_{ch} h\_{ch} \right) = \mathcal{Z} \times \left( \mathbf{1.25} \times \mathbf{0.75} + \mathbf{1.15} \times \mathbf{0.75} \right) = \mathbf{3.6} \, m^2 \tag{13}$$

After expanding the top of the drying chamber on computer by AutoCAD software, the surrounding area of a top is*Ft* <sup>¼</sup> <sup>1</sup>*:*<sup>62</sup> *<sup>m</sup>*2.

So, the area of the drying chamber is

$$F = F\_w + 2.F\_t = 6,847 \, m^2 \tag{14}$$

The heat loss is calculated as

$$Q\_6 = q\_\xi F = k \left( t\_{inside}^{ch} - t\_{outside}^{ch} \right) F = 0.212 \text{ kW} \tag{15}$$

in which k is thermal conductivity of galvanized steel and k is 2.06 W/(m.<sup>o</sup> C). lch, wch, and hch are the length, the width, and the height of the drying chamber.

#### *3.1.7 Radiation heat loss*

The radiation heat loss is calculated as

$$Q\_{\mathcal{T}} = \varepsilon.F.C\_{\bullet}.\left[\left(\frac{T\_f}{100}\right)^4 - \left(\frac{T\_i}{100}\right)^4\right] = 0.593\,kW\tag{16}$$

in which ε is the radiation ratio of galvanized steel, ε = 0.85, and C0 is the radiation ratio of absolute black object, *<sup>C</sup>*<sup>0</sup> <sup>¼</sup> <sup>5</sup>*:*67*W<sup>=</sup> <sup>m</sup>*<sup>2</sup>*:K*<sup>4</sup> � �.

Thus, the total heat required for drying process is

$$\mathbf{Q\_{total}} = \mathbf{Q\_1} + \mathbf{Q\_2} + \mathbf{Q\_3} + \mathbf{Q\_4} + \mathbf{Q\_5} + \mathbf{Q\_6} + \mathbf{Q\_7} = \mathbf{3.632 kW} \tag{17}$$

In current study, the RF operator will be designed, manufactured, and applied in RF-assisted heat pump drying. So, in the drying process, RF heating has the main function of heating the material, vaporizing water within the material, and heating the drying tray. The other heat losses are supplied by heat pump. Thus, the heat required for RF generator is.

$$\mathbf{Q\_{RF}} = \mathbf{Q\_1} + \mathbf{Q\_2} + \mathbf{Q\_3} = 2.307 \text{ kW} \tag{18}$$

Therefore, the RF power of RF generator is chosen P = 3 kW.

#### **3.2 Circuit diagram of RF generator**

The circuit diagram of RF generator was designed based on the theory of RF heating mechanism, heat exchanger, and oscillator circuit of RF generator [11]. The circuit diagram of RF generator is described in **Figure 2**.

through the RF emitting circuit, and it is supplied to the electrode plates of the

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying…*

The drying applicator is composed of two parallel electrode plates which

The high-frequency triode tube is selected in the market according to the

The output power of 5 kW will be converted to RF electrode plates in drying

The transformers and the rectifier were manufactured at the workshop with the

engineering specifications required. The transformer and rectifier are shown in

electrodes during drying process. The material is heated based on dielectric

are called RF electrodes. The drying material is placed between the

required RF power, and it has the specific specifications as follows:

**3.3 Fabricating the components of the RF generator**

drying applicator.

heating principle.

*3.3.1 High-frequency triode tube*

• Type: Toshiba 7T69RB.

• Frequency: 27 MHz.

*3.3.2 Power supply unit*

**Figures 4** and **5**.

**Figure 3.**

**65**

*High-frequency triode tube.*

• Voltage applied to filament: 12.6 VAC.

• Voltage applied to anode: 6.5 kVDC.

• Output power (maximum): 5 kW.

applicator at 60% efficiency (**Figure 3**).

*3.2.4 Drying applicator*

*DOI: http://dx.doi.org/10.5772/intechopen.88825*

#### *3.2.1 Power supply unit*

The power supply unit consists of a transformer, a wire supply voltage transformer, and a rectifier.

The transformer has the function of changing three-phase voltage 380 VAC into 6.5 kVAC. This high voltage is converted into DC voltage of 6.5 kVDC by the rectifier and supplied to the oscillation circuit. Besides, the wire supply voltage transformer will change the voltage from 380 VAC to 12.6 VAC to supply the triode tube filament.

#### *3.2.2 Oscillation circuit*

The oscillation circuit consists of a high-frequency triode tube and LC oscillation circuits. A high voltage of 6.5 kVDC is applied to the anode of the triode tube after passing through an induction circuit including L1, L2, and C1 that acts as a filter circuit to remove the alternating current components of the supply power.

A high voltage of 12.6 VAC is applied to the filament and grid pin of the triode tube. A 12.6 VAC power is applied to the grid pin of the triode tube through an induction circuit that consists of L5, L6, and C4. The induction circuit controls the voltage of the grid pin to generate the output frequency at 27 MHz.

#### *3.2.3 RF emitting circuit*

The RF emitting circuit is a circuit consisting of L3 and C3 in parallel. The RF high-frequency energy at the output of the high-frequency triode tube passes

**Figure 2.** *The circuit diagram of RF generator.*

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying… DOI: http://dx.doi.org/10.5772/intechopen.88825*

through the RF emitting circuit, and it is supplied to the electrode plates of the drying applicator.

#### *3.2.4 Drying applicator*

**3.2 Circuit diagram of RF generator**

*Innovation in Global Green Technologies 2020*

*3.2.1 Power supply unit*

former, and a rectifier.

*3.2.2 Oscillation circuit*

*3.2.3 RF emitting circuit*

**Figure 2.**

**64**

*The circuit diagram of RF generator.*

tube filament.

circuit diagram of RF generator is described in **Figure 2**.

The circuit diagram of RF generator was designed based on the theory of RF heating mechanism, heat exchanger, and oscillator circuit of RF generator [11]. The

The power supply unit consists of a transformer, a wire supply voltage trans-

6.5 kVAC. This high voltage is converted into DC voltage of 6.5 kVDC by the rectifier and supplied to the oscillation circuit. Besides, the wire supply voltage transformer will change the voltage from 380 VAC to 12.6 VAC to supply the triode

The transformer has the function of changing three-phase voltage 380 VAC into

The oscillation circuit consists of a high-frequency triode tube and LC oscillation circuits. A high voltage of 6.5 kVDC is applied to the anode of the triode tube after passing through an induction circuit including L1, L2, and C1 that acts as a filter circuit to remove the alternating current components of the supply power.

A high voltage of 12.6 VAC is applied to the filament and grid pin of the triode tube. A 12.6 VAC power is applied to the grid pin of the triode tube through an induction circuit that consists of L5, L6, and C4. The induction circuit controls the

The RF emitting circuit is a circuit consisting of L3 and C3 in parallel. The RF high-frequency energy at the output of the high-frequency triode tube passes

voltage of the grid pin to generate the output frequency at 27 MHz.

The drying applicator is composed of two parallel electrode plates which are called RF electrodes. The drying material is placed between the electrodes during drying process. The material is heated based on dielectric heating principle.

#### **3.3 Fabricating the components of the RF generator**

#### *3.3.1 High-frequency triode tube*

The high-frequency triode tube is selected in the market according to the required RF power, and it has the specific specifications as follows:


The output power of 5 kW will be converted to RF electrode plates in drying applicator at 60% efficiency (**Figure 3**).

#### *3.3.2 Power supply unit*

The transformers and the rectifier were manufactured at the workshop with the engineering specifications required. The transformer and rectifier are shown in **Figures 4** and **5**.

**Figure 3.** *High-frequency triode tube.*

**Figure 4.** *Transformer.*

*3.3.4 RF emitting circuit*

*Inductor coil and capacitor.*

**Figure 6.**

specifications below.

(*<sup>k</sup>* <sup>¼</sup> <sup>9</sup> � <sup>10</sup><sup>9</sup>*N:m*<sup>2</sup>*=C*<sup>2</sup>

f = 27 MHz as follows:

follows:

**67**

and distance between them.

distance of two electrode plates is *dC*<sup>3</sup> ¼ 0*:*1 *m*.

• Inductance value: *<sup>L</sup>*<sup>3</sup> <sup>¼</sup> <sup>1</sup>*:*9*x*10�<sup>6</sup> *<sup>H</sup>*.

• Material: a copper wire.

The capacitance value of capacitor C3 is calculated as

*<sup>C</sup>*<sup>3</sup> <sup>¼</sup> *<sup>ε</sup>*0*:AC*<sup>3</sup> 4*π:k:dC*<sup>3</sup>

) is electrostatic constant.

*<sup>L</sup>*<sup>3</sup> <sup>¼</sup> <sup>1</sup> ð Þ <sup>2</sup>*π: <sup>f</sup>* <sup>2</sup>

of 27 MHz. So, the inductance value of L3 is calculated with the parameter

The structure of RF emitting circuit is composed of L3 and C3 in parallel that forms an induction circuit. The RF emitting circuit has the function of generating operating frequency of 27 MHz that is the technical requirements. L3 and C3 are manufactured in the workshop according to the technical requirements with the

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying…*

*DOI: http://dx.doi.org/10.5772/intechopen.88825*

The structure of the capacitor C3 consists of two parallel electrode plates. The capacitance value of capacitor C3 depends on the area of the parallel electrode plates

The electrode plates have an area of *AC*<sup>3</sup> <sup>¼</sup> <sup>0</sup>*:*<sup>45</sup> � <sup>0</sup>*:*<sup>45</sup> <sup>¼</sup> <sup>0</sup>*:*<sup>203</sup> *<sup>m</sup>*2, and the

in which *ε*0(*ε*<sup>0</sup> ≈ 1) is dielectric constant of air between two plates and k

*:C*<sup>3</sup>

The inductor L3 is manufactured in workshop with its specific specification as

The function of the L3 and C3 induction circuit is generating operating frequency

<sup>¼</sup> <sup>1</sup>*:*<sup>8</sup> � <sup>10</sup>�<sup>11</sup> *<sup>F</sup>* (19)

<sup>¼</sup> <sup>1</sup>*:*9*x*10�<sup>6</sup> *<sup>H</sup>* (20)

**Figure 5.** *Rectifier.*

#### *3.3.3 Oscillation circuit*

The oscillation circuit consists of numbers of capacitors and the inductor coils. The function of the oscillation circuit is amplifying the power and required generating frequency. The capacitors and the inductor coils are the industrial components that can work at the high voltage and high frequency (**Figure 6**).

The oscillation circuit consists of two induction circuits:


These capacitors and the inductor coils are selected and manufactured according to the standard in Strayfield's handbook for manufacturing RF generator [11], in which the capacitors C1 and C4 are selected in the market, while the inductors L1, L2, L4, and L5 are manufactured at the workshop. Their values are as follows:

$$C\_1 = C\_2 = 1500 \text{ pF}; C\_4 = C\_5 = C\_6 = 500 \text{ pF}; L\_1 = L\_2 = L\_4 = L\_5 = 1.5 \times 10^{-6} H.$$

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying… DOI: http://dx.doi.org/10.5772/intechopen.88825*

**Figure 6.** *Inductor coil and capacitor.*

#### *3.3.4 RF emitting circuit*

The structure of RF emitting circuit is composed of L3 and C3 in parallel that forms an induction circuit. The RF emitting circuit has the function of generating operating frequency of 27 MHz that is the technical requirements. L3 and C3 are manufactured in the workshop according to the technical requirements with the specifications below.

The structure of the capacitor C3 consists of two parallel electrode plates. The capacitance value of capacitor C3 depends on the area of the parallel electrode plates and distance between them.

The electrode plates have an area of *AC*<sup>3</sup> <sup>¼</sup> <sup>0</sup>*:*<sup>45</sup> � <sup>0</sup>*:*<sup>45</sup> <sup>¼</sup> <sup>0</sup>*:*<sup>203</sup> *<sup>m</sup>*2, and the distance of two electrode plates is *dC*<sup>3</sup> ¼ 0*:*1 *m*.

The capacitance value of capacitor C3 is calculated as

$$C\_3 = \frac{\varepsilon\_0 A\_{C3}}{4\pi \, k \, d\_{C3}} = 1.8 \times 10^{-11} \, F \tag{19}$$

in which *ε*0(*ε*<sup>0</sup> ≈ 1) is dielectric constant of air between two plates and k (*<sup>k</sup>* <sup>¼</sup> <sup>9</sup> � <sup>10</sup><sup>9</sup>*N:m*<sup>2</sup>*=C*<sup>2</sup> ) is electrostatic constant.

The function of the L3 and C3 induction circuit is generating operating frequency of 27 MHz. So, the inductance value of L3 is calculated with the parameter f = 27 MHz as follows:

$$L\_3 = \frac{1}{\left(2\pi f\right)^2 \cdot C\_3} = 1.9 \text{x} 10^{-6} \text{ } H\tag{20}$$

The inductor L3 is manufactured in workshop with its specific specification as follows:


*3.3.3 Oscillation circuit*

**Figure 5.** *Rectifier.*

**66**

**Figure 4.** *Transformer.*

*Innovation in Global Green Technologies 2020*

The oscillation circuit consists of numbers of capacitors and the inductor coils. The function of the oscillation circuit is amplifying the power and required generating frequency. The capacitors and the inductor coils are the industrial components

1.The L1, L2, and C1 induction circuit works as a filter circuit to remove the

2.The L4, L5, and C4 induction circuit regulates the voltage at the grid pin of the

These capacitors and the inductor coils are selected and manufactured according to the standard in Strayfield's handbook for manufacturing RF generator [11], in which the capacitors C1 and C4 are selected in the market, while the inductors L1, L2, L4, and L5 are manufactured at the workshop. Their values are as follows:

*<sup>C</sup>*<sup>1</sup> <sup>¼</sup> *<sup>C</sup>*<sup>2</sup> <sup>¼</sup> <sup>1500</sup> pF; *<sup>C</sup>*<sup>4</sup> <sup>¼</sup> *<sup>C</sup>*<sup>5</sup> <sup>¼</sup> *<sup>C</sup>*<sup>6</sup> <sup>¼</sup> <sup>500</sup> pF; *<sup>L</sup>*<sup>1</sup> <sup>¼</sup> *<sup>L</sup>*<sup>2</sup> <sup>¼</sup> *<sup>L</sup>*<sup>4</sup> <sup>¼</sup> *<sup>L</sup>*<sup>5</sup> <sup>¼</sup> <sup>1</sup>*:*<sup>5</sup> � <sup>10</sup>�<sup>6</sup>*H:*

that can work at the high voltage and high frequency (**Figure 6**). The oscillation circuit consists of two induction circuits:

high-frequency triode tube to generate the output RF.

alternating current components.


#### *3.3.5 Drying applicator*

The drying applicator consists of two electrode plates which are called RF electrodes. The RF electrodes are fabricated at the workshop. The material used for fabrication of RF electrodes must be a good electric conductive material, and aluminum is chosen. The electrodes have a rectangular surface and dimension of 1200 mm 1100 mm. They are fixed in drying chamber and connect to the RF emitting circuit through thin copper connectors. The distance between two electrodes is fixed by Teflon plastic bars. The RF electrodes are shown in **Figure 7**.

#### **3.4 Drying experiment results**

The RF-assisted heat pump dryer used in drying experiment is shown in **Figures 8** and **9**. In the drying process, the drying air is circulated over the evaporator of heat pump. The evaporator cools the drying air further down below the condensation temperature. Below this temperature, the drying air will be dehumidified. Then, the drying air is heated to the desired temperature inside the condenser and blown inside the drying chamber for drying process. In the drying chamber, the drying air will combine with the RF generated by the RF generator to conduct drying process of *Ganoderma lucidum*.

In drying experiment, the mass of *Ganoderma lucidum* selected is 4 kg. Thus, the RF power is adjusted to achieve the value of 0.65, 1.3, and 1.95 kW.

#### *3.4.1 Result of operating parameters of RF generator*

The RF generator is operated with the maximum RF power of 3 kW to inspect the operating parameters. The operating frequency of RF generator (f) is measured by a frequency measurement instrument, the operating voltage (U) is measured by a high-voltage voltmeter, and the operating current (I) is measured by an amperemeter. The temperature of the material in drying process is measured by a thermal sensor that is connected to a computer through an integrated circuit. The temperature is recorded each 2 minutes.

The measurement of the operating parameters of RF operator has got the results

• f = 27 MHz, U = 6.5 kV, I = 0.46 A. So, the power P = U.I = 2.99 kW.

*RF-assisted heat pump dryer model. (1) compressor, (2) sub-condenser, (3) valve, (4) condenser, (5) evaporator, (6) heat pump controller, (7) air fan, (8) drying tray, (9) drying chamber, (10) RF electrodes, (11) RF operating controller, (12) operating current intensity controller, (13) unit of supplying the*

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying…*

*DOI: http://dx.doi.org/10.5772/intechopen.88825*

• The material is heated and achieves the required temperature of 45°C in

as follows:

**69**

**Figure 9.**

**Figure 8.**

*operating voltage.*

28 minutes.

*RF-assisted heat pump dryer.*

**Figure 7.** *Electrode plates.*

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying… DOI: http://dx.doi.org/10.5772/intechopen.88825*

#### **Figure 8.**

• Diameter of wire: 2.5 mm.

**3.4 Drying experiment results**

conduct drying process of *Ganoderma lucidum*.

*3.4.1 Result of operating parameters of RF generator*

temperature is recorded each 2 minutes.

**Figure 7.** *Electrode plates.*

**68**

*3.3.5 Drying applicator*

• Diameter of wire coil: 40 mm.

*Innovation in Global Green Technologies 2020*

The drying applicator consists of two electrode plates which are called RF electrodes. The RF electrodes are fabricated at the workshop. The material used for fabrication of RF electrodes must be a good electric conductive material, and aluminum is chosen. The electrodes have a rectangular surface and dimension of 1200 mm 1100 mm. They are fixed in drying chamber and connect to the RF emitting circuit through thin copper connectors. The distance between two electrodes is fixed by Teflon plastic bars. The RF electrodes are shown in **Figure 7**.

The RF-assisted heat pump dryer used in drying experiment is shown in **Figures 8** and **9**. In the drying process, the drying air is circulated over the evaporator of heat pump. The evaporator cools the drying air further down below the condensation temperature. Below this temperature, the drying air will be

dehumidified. Then, the drying air is heated to the desired temperature inside the condenser and blown inside the drying chamber for drying process. In the drying chamber, the drying air will combine with the RF generated by the RF generator to

RF power is adjusted to achieve the value of 0.65, 1.3, and 1.95 kW.

a high-voltage voltmeter, and the operating current (I) is measured by an

In drying experiment, the mass of *Ganoderma lucidum* selected is 4 kg. Thus, the

The RF generator is operated with the maximum RF power of 3 kW to inspect the operating parameters. The operating frequency of RF generator (f) is measured by a frequency measurement instrument, the operating voltage (U) is measured by

amperemeter. The temperature of the material in drying process is measured by a thermal sensor that is connected to a computer through an integrated circuit. The

*RF-assisted heat pump dryer model. (1) compressor, (2) sub-condenser, (3) valve, (4) condenser, (5) evaporator, (6) heat pump controller, (7) air fan, (8) drying tray, (9) drying chamber, (10) RF electrodes, (11) RF operating controller, (12) operating current intensity controller, (13) unit of supplying the operating voltage.*

**Figure 9.** *RF-assisted heat pump dryer.*

The measurement of the operating parameters of RF operator has got the results as follows:


The results show that the operation parameters achieve the designing requirement.

The engineering parameters of measurement instruments are described in the **Table 1**.

fluctuate faster. Thus, heat generation within *Ganoderma lucidum* becomes faster, and the moisture diffusion within *Ganoderma lucidum* occurs faster [12, 13].

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying…*

The polysaccharide content of *Ganoderma lucidum* after drying is given in **Table 3**. The data in **Table 3** shows that RF power has a significant effect on polysaccharide content of *Ganoderma lucidum* after drying. The polysaccharide content of *Ganoderma lucidum* after RF-assisted heat pump drying is considerably higher than heat pump drying. Increase in RF power retains the higher content of polysaccharide in *Ganoderma lucidum*. Generally, the reason for the degradation of polysaccharide content during drying of *Ganoderma lucidum* is due to hydrolysis, in which the polysaccharide is hydrolyzed as water is bound to the molecule [14]. RF-assisted heat pump drying process with RF heating mechanism shortens the heat treatment time, and an increase in RF power makes the linkage between water dipole molecules to be broken more easily. That can reduce the hydrolysis degree of polysac-

Evaluation of the color change of *Ganoderma lucidum* before and after drying is

conducted with X-Rite colorimeter following CIELAB scale. Fresh *Ganoderma lucidum* has the CIELAB original color value as L0, a0, and b0. *Ganoderma lucidum* after drying has the CIELAB color value as L\*, a\*, and b\*. The color change index of *Ganoderma lucidum* corresponding to input drying parameters is shown in **Table 4**, in which the International Commission on Illumination (CIE) parameters as L, a, and b are measured with a colorimeter (see **Table 1**). The corresponding L value is lightness of color from 0 (black) to 100 (white); a value is degree of redness (0 to 60) or greenness (0 to �60); and b value is yellowness (0 to

60) or blueness (0 to �60). The total change in color (*ΔE*<sup>∗</sup> <sup>Þ</sup> of the drying *Ganoderma lucidum* sample with reference to the original sample is calculated as

Fresh samples 47.12 4.11 18.85

The data in **Table 4** shows that the color change index as ΔL, Δa, and Δb corresponding to RF-assisted heat pump drying is considerably smaller than

**Color index Type of sample CIELAB color value Color change index**

**L0 a0 b0**

Heat pump drying (PRF = 0 kW) 36.5<sup>a</sup> 6.94<sup>a</sup> 12.52<sup>a</sup> 10.62 2.83 6.33 12.68<sup>a</sup>

*Mean values in the same column with different letter symbols. Significant difference at significance level of 0.05.*

L\* a\* b\* ΔL Δa Δb ΔE\*

38.71b 5.75b 13.76<sup>b</sup> 8.41 1.64 5.09 9.97<sup>b</sup>

39.02<sup>c</sup> 5.42<sup>c</sup> 14.1c 8.1 1.31 4.75 9.48<sup>c</sup>

39.35d 5.12d 14.46<sup>d</sup> 7.77 1.01 4.39 8.98<sup>d</sup>

*3.4.2.2 Polysaccharide content*

*DOI: http://dx.doi.org/10.5772/intechopen.88825*

*3.4.2.3 Color of drying material*

RF-assisted heat pump drying

RF-assisted heat pump drying

RF-assisted heat pump drying

*The CIELAB color values of* Ganoderma lucidum*.*

(PRF = 0.65 kW)

(PRF = 1.3 kW)

(PRF = 1.95 kW)

**Table 4.**

**71**

charides.

Eq. (1).

#### *3.4.2 Evaluation of the effect of RF power*

#### *3.4.2.1 Drying time*

The drying curves of RF-assisted heat pump drying process at the drying air temperature of 45°C, drying air velocity of 1.2 m/s, and RF power of 0.65, 1.3, and 1.95 kW is presented graphically in **Figure 10**.

As shown in **Figure 10**, increasing RF power has a significant effect on moisture ratio; the moisture ratio is higher at higher RF power. At RF power of 1.95 kW, the drying time reduces by 9, 17, and 33% in comparison with RF power of 1.3, 0.65, and 0 kW (heat pump drying). It can be explained by RF heating mechanism, in which, increasing the RF power will increase energy absorption inside *Ganoderma lucidum*, which makes water dipole molecules and free ions in *Ganoderma lucidum*

**Figure 10.** *Drying curves of RF-assisted heat pump drying process at different RF powers.*


**Table 3.**

*Polysaccharide content of* Ganoderma lucidum *after drying.*

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying… DOI: http://dx.doi.org/10.5772/intechopen.88825*

fluctuate faster. Thus, heat generation within *Ganoderma lucidum* becomes faster, and the moisture diffusion within *Ganoderma lucidum* occurs faster [12, 13].

#### *3.4.2.2 Polysaccharide content*

The results show that the operation parameters achieve the designing

The engineering parameters of measurement instruments are described in the

The drying curves of RF-assisted heat pump drying process at the drying air temperature of 45°C, drying air velocity of 1.2 m/s, and RF power of 0.65, 1.3, and

As shown in **Figure 10**, increasing RF power has a significant effect on moisture ratio; the moisture ratio is higher at higher RF power. At RF power of 1.95 kW, the drying time reduces by 9, 17, and 33% in comparison with RF power of 1.3, 0.65, and 0 kW (heat pump drying). It can be explained by RF heating mechanism, in which, increasing the RF power will increase energy absorption inside *Ganoderma lucidum*, which makes water dipole molecules and free ions in *Ganoderma lucidum*

requirement.

*3.4.2.1 Drying time*

*3.4.2 Evaluation of the effect of RF power*

*Innovation in Global Green Technologies 2020*

1.95 kW is presented graphically in **Figure 10**.

*Drying curves of RF-assisted heat pump drying process at different RF powers.*

**ta (°C) va (m/s) PRF (kW)**

*Polysaccharide content of* Ganoderma lucidum *after drying.*

 45 1.2 0 7.82 45 1.2 0.65 9.18 45 1.2 1.3 9.31 45 1.2 1.95 9.47

**No Input drying parameter Polysaccharide content (mg/g)**

**Table 1**.

**Figure 10.**

**Table 3.**

**70**

The polysaccharide content of *Ganoderma lucidum* after drying is given in **Table 3**. The data in **Table 3** shows that RF power has a significant effect on polysaccharide content of *Ganoderma lucidum* after drying. The polysaccharide content of *Ganoderma lucidum* after RF-assisted heat pump drying is considerably higher than heat pump drying. Increase in RF power retains the higher content of polysaccharide in *Ganoderma lucidum*. Generally, the reason for the degradation of polysaccharide content during drying of *Ganoderma lucidum* is due to hydrolysis, in which the polysaccharide is hydrolyzed as water is bound to the molecule [14]. RF-assisted heat pump drying process with RF heating mechanism shortens the heat treatment time, and an increase in RF power makes the linkage between water dipole molecules to be broken more easily. That can reduce the hydrolysis degree of polysaccharides.

#### *3.4.2.3 Color of drying material*

Evaluation of the color change of *Ganoderma lucidum* before and after drying is conducted with X-Rite colorimeter following CIELAB scale. Fresh *Ganoderma lucidum* has the CIELAB original color value as L0, a0, and b0. *Ganoderma lucidum* after drying has the CIELAB color value as L\*, a\*, and b\*. The color change index of *Ganoderma lucidum* corresponding to input drying parameters is shown in **Table 4**, in which the International Commission on Illumination (CIE) parameters as L, a, and b are measured with a colorimeter (see **Table 1**). The corresponding L value is lightness of color from 0 (black) to 100 (white); a value is degree of redness (0 to 60) or greenness (0 to �60); and b value is yellowness (0 to 60) or blueness (0 to �60). The total change in color (*ΔE*<sup>∗</sup> <sup>Þ</sup> of the drying *Ganoderma lucidum* sample with reference to the original sample is calculated as Eq. (1).


The data in **Table 4** shows that the color change index as ΔL, Δa, and Δb corresponding to RF-assisted heat pump drying is considerably smaller than

#### **Table 4.**

*The CIELAB color values of* Ganoderma lucidum*.*

heat pump drying and increase in RF power decreases the color change index values. Thus, the *Ganoderma lucidum* samples have retained the color better at higher RF power and at RF power of 1.95 kW, and the color of *Ganoderma lucidum* samples is nearly similar to the original brown red of fresh material samples.

#### *3.4.3 Evaluation of the effect of drying air temperature*

The drying curves of RF-assisted heat pump drying process at the drying air temperature of 40, 45, and 50°C, drying air velocity of 1.2 m/s, and RF power of 1.3 kW is presented graphically in **Figure 11**.

As shown in **Figure 11**, increasing drying air temperature has a significant effect on moisture ratio; the moisture ratio is higher at higher drying air temperature. At drying air temperature of 50°C, the drying time reduces by 10% and 21% in comparison with drying air temperature of 40 and 45°C. It can be explained by the fact that the increase in drying air temperature will increase the amount of heat absorbed by material. Thus, the heating rate increases, and the moisture diffusion within *Ganoderma lucidum* occurs faster.

> temperature of drying material is maintained at a higher level than drying air temperature during drying process by RF heating mechanism. So, when drying air comes into contact with drying material surfaces, the temperature of material surfaces will decrease that causes the average temperature of material to decrease and drying time to become longer. However, drying air velocity does not significantly affect the drying rate. The drying time corresponding to three drying air velocity values differs only about 10–15 minutes, and the drying curves shown in **Figure 12** are almost identical. The experimental results are in agreement with the

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying…*

*DOI: http://dx.doi.org/10.5772/intechopen.88825*

*Drying curves of RF-assisted heat pump drying process at different drying air velocities.*

Based on the calculation and design results, the RF generator has been successfully manufactured and applied in drying technology. The RF generator worked efficiently and achieved the required RF power of 3 kW and frequency of 27 MHz as designed. The drying experiment results showed that in RF-assisted heat pump drying, increase in RF power and drying air temperature increases the drying rate considerably. Meanwhile, drying air velocity does not significantly affect the drying rate. Besides, when RF power increases, the *Ganoderma lucidum* samples retain the

higher content of polysaccharide and the original color better after drying.

Cp specific heat of drying material, J/(kg °C)

d.b dry basic (kg H2O/kg dry solid)

Gb drying capacity, kg/batch

previous studies of agricultural product drying [15–18].

**4. Conclusions**

**Figure 12.**

**Nomenclature**

**73**

AC alternating current

C capacitor

DC direct current f frequency, MHz

h the height, m

#### *3.4.4 Evaluation of the effect of drying air velocity*

The drying curves of RF-assisted heat pump drying process at the drying air temperature of 45°C; drying air velocity of 1.2, 1.6, and 2 m/s; and RF power of 1.3 kW is presented graphically in **Figure 12**.

As shown in **Figure 12**, increasing drying air velocity makes drying time become longer. This is explained by the fact that the increase in drying air velocity will increase the drying airflow in contact with the drying material surfaces. The

**Figure 11.** *Drying curves of RF-assisted heat pump drying process at different drying air temperatures.*

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying… DOI: http://dx.doi.org/10.5772/intechopen.88825*

#### **Figure 12.**

heat pump drying and increase in RF power decreases the color change index values. Thus, the *Ganoderma lucidum* samples have retained the color better at higher RF power and at RF power of 1.95 kW, and the color of *Ganoderma lucidum* samples is nearly similar to the original brown red of fresh material

The drying curves of RF-assisted heat pump drying process at the drying air temperature of 40, 45, and 50°C, drying air velocity of 1.2 m/s, and RF power of

that the increase in drying air temperature will increase the amount of heat absorbed by material. Thus, the heating rate increases, and the moisture diffusion

The drying curves of RF-assisted heat pump drying process at the drying air temperature of 45°C; drying air velocity of 1.2, 1.6, and 2 m/s; and RF power of

longer. This is explained by the fact that the increase in drying air velocity will increase the drying airflow in contact with the drying material surfaces. The

*Drying curves of RF-assisted heat pump drying process at different drying air temperatures.*

As shown in **Figure 12**, increasing drying air velocity makes drying time become

As shown in **Figure 11**, increasing drying air temperature has a significant effect on moisture ratio; the moisture ratio is higher at higher drying air temperature. At drying air temperature of 50°C, the drying time reduces by 10% and 21% in comparison with drying air temperature of 40 and 45°C. It can be explained by the fact

*3.4.3 Evaluation of the effect of drying air temperature*

1.3 kW is presented graphically in **Figure 11**.

*Innovation in Global Green Technologies 2020*

within *Ganoderma lucidum* occurs faster.

*3.4.4 Evaluation of the effect of drying air velocity*

1.3 kW is presented graphically in **Figure 12**.

samples.

**Figure 11.**

**72**

*Drying curves of RF-assisted heat pump drying process at different drying air velocities.*

temperature of drying material is maintained at a higher level than drying air temperature during drying process by RF heating mechanism. So, when drying air comes into contact with drying material surfaces, the temperature of material surfaces will decrease that causes the average temperature of material to decrease and drying time to become longer. However, drying air velocity does not significantly affect the drying rate. The drying time corresponding to three drying air velocity values differs only about 10–15 minutes, and the drying curves shown in **Figure 12** are almost identical. The experimental results are in agreement with the previous studies of agricultural product drying [15–18].

#### **4. Conclusions**

Based on the calculation and design results, the RF generator has been successfully manufactured and applied in drying technology. The RF generator worked efficiently and achieved the required RF power of 3 kW and frequency of 27 MHz as designed. The drying experiment results showed that in RF-assisted heat pump drying, increase in RF power and drying air temperature increases the drying rate considerably. Meanwhile, drying air velocity does not significantly affect the drying rate. Besides, when RF power increases, the *Ganoderma lucidum* samples retain the higher content of polysaccharide and the original color better after drying.

#### **Nomenclature**



**References**

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[10] Van Phu T. Calculating and Designing Drying System. Ha Noi, Vietnam: Education Publisher; 2002.

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**75**

### **Greek symbols**


#### **Subscripts**


## **Author details**

Nguyen Hay<sup>1</sup> \*, Le Anh Duc<sup>1</sup> \* and Pham Van Kien<sup>2</sup>

1 Nong Lam University, Ho Chi Minh City, Vietnam

2 LILAMA2 International Technology College, Dong Nai, Vietnam

\*Address all correspondence to: ng.hay@hcmuaf.edu.vn and leanhduc@hcmuaf.edu.vn

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Study on Designing and Manufacturing a Radio-Frequency Generator Used in Drying… DOI: http://dx.doi.org/10.5772/intechopen.88825*

#### **References**

HP heat pump

*Innovation in Global Green Technologies 2020*

I ampere, A l the length, m L inductor coil

PRF RF power, kW Q the heat, kW

RF radio frequency

U voltage, kV w the width, m

*τ* the time, s

i initial f final W water ch chamber

**Greek symbols**

**Subscripts**

**Author details**

\*, Le Anh Duc<sup>1</sup>

provided the original work is properly cited.

\*Address all correspondence to:

1 Nong Lam University, Ho Chi Minh City, Vietnam

ng.hay@hcmuaf.edu.vn and leanhduc@hcmuaf.edu.vn

2 LILAMA2 International Technology College, Dong Nai, Vietnam

Nguyen Hay<sup>1</sup>

**74**

LSD least significant difference mLC mass of *Ganoderma lucidum*, kg M moisture of drying material, d.b

t temperature of drying material, °C

w.b wet basic (kg H2O/kg wet solid)

λ thermal conductivity, W/m °C ω moisture of drying material, w.b ε radiation ratio of galvanized steel

T absolute temperature of drying material, °K

HPLC high-performance liquid chromatography

r latent heat of vaporization of moisture in material, J/kg

\* and Pham Van Kien<sup>2</sup>

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

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Section 3

Recycling and Waste

Management

Section 3
