**1. Introduction**

UWB is an emerging wireless communication technology that introduces a wide approach of wireless techniques in various disciplines, especially in medical applications. This technology works with a frequency range of 3.1–10.6 GHz and power spectrum density (PSD) of 41.3 dBm/MHz according to the American Federal Communications Commission (FCC) as depicted in **Figure 1** [1] and International Commission on Non-Ionizing Radiation Protection (ICNIRP) safety guidelines [2]. This frequency range with low-power consumption makes the technology suitable for use in medical applications. It has no biological side effects and has nonionizing radiation (only thermal effect) as well as it has a good ability to penetrate the human tissues. These features encourage the researchers to propose many studies that have invested UWB in medical applications; most of these papers would focus either on the differences in the dielectric properties of human tissue like breast cancer detection, or on the organ movement detection like heart rate and respiratory detection. The main problems that have been faced by such researches are the absorption and attenuation of the signal by the skin and the vicinity layers, while the returning signal from the deep layers is very weak, as well as the inability to distinguish between the tissues that have convergent dielectric properties. These problems will introduce new challenges to be solved by researchers.

### **1.1 UWB advantages and features in medical application**

• Good ability of penetration for human tissue.

where A is the pulse amplitude, t is time, and ԏ is a time constant as illustrated in **Figure 2** [4]. So, it has safe electromagnetic field according to FCC and the *International Commission on Non-Ionizing Radiation Protection (*ICNIRP) guidelines and it may be causing thermal effects related to the power absorption by human tissue

The dielectric properties are the fundamental parameters that affect the propagation of the electric field. It is a measure of how electric field behaves or interacts with materials, which can be used (for example) to understand how easily an electric field will polarize a given dielectric material. Dielectric constant and loss tangent are both numerical values using which permittivity of a dielectric material can be defined. And the conductivity is the extent of electric current that flow through it. Where the conductivity is used for the rate or degree that electromag-

The dielectric properties of blood have been affected by many coefficients like blood temperature [6], applied electromagnetic wave frequency, clotting rate, human gender [7], blood group type (A, B, AB, and O) [8], blood composition,

**1.4 Blood dielectric properties measurement using open-ended coaxial probe**

these differences will enable the recognizing of the tissues by recognizing its dielectric properties [10]. This experiment attempts to improve the blood dielectric properties individually for increasing the blood appearing over other substances (perfect blood image). This microwave measurement method (experiment) has been applied in 5 GHz frequency center and in a temperature of 37°C; the blood samples with different additions and concentrations have been tested and the results have been recorded. The required experiment devices are shown in **Figure 3**.

The dielectric properties will be different from one material to another where

netic wave, electricity, heat, or sound travel through a certain medium.

blood hematocrit level, and hemoglobin percentage [9].

[1, 2, 5].

**Figure 2.**

**73**

*Fifth derivative Gaussian pulse [4].*

**1.3 The dielectric properties**

*Medical Application of Ultra-Wideband Technology DOI: http://dx.doi.org/10.5772/intechopen.93577*

#### **Figure 1.**

*Indoor power spectrum mask from FCC [1].*


#### **1.2 UWB monocycle pulses**

UWB medical radar naturally deals with human body tissues, which will absorb and affect on the radiated energy of UWB pulses, so we have a challenge with increasing the radiated energy without crossing the FCC mask [1], which depends on the Gaussian pulse shape (derivative order), width, and repetition time (frequency). Here, the first derivative of Gaussian pulse equation is:

$$\mathbf{G}\mathbf{s}(\mathbf{t}) = \mathbf{A} \cdot \exp\left[-\left(\frac{\mathbf{t}}{\mathbf{v}}\right)^{2}\right] \tag{1}$$

and the fifth derivative of Gaussian pulses is as the following as in Eq. (2), and the frequency range of indoor application from 4 to 6 GHz introduces the best performance and best masking to FCC [1, 3]:

$$\mathbf{G}\mathbf{s}(\mathbf{t}) = \mathbf{A}\left(-\frac{\mathbf{t}^{\mathsf{5}}}{\sqrt{2\pi}\mathbf{v}^{11}} + \frac{10\mathbf{t}^{\mathsf{3}}}{\sqrt{2\pi}\mathbf{v}^{9}} + \frac{15\mathbf{t}}{\sqrt{2\pi}\mathbf{v}^{7}}\right)\exp\left(-\frac{\mathbf{t}^{2}}{2\mathbf{v}^{2}}\right) \tag{2}$$

*Medical Application of Ultra-Wideband Technology DOI: http://dx.doi.org/10.5772/intechopen.93577*

where A is the pulse amplitude, t is time, and ԏ is a time constant as illustrated in **Figure 2** [4]. So, it has safe electromagnetic field according to FCC and the *International Commission on Non-Ionizing Radiation Protection (*ICNIRP) guidelines and it may be causing thermal effects related to the power absorption by human tissue [1, 2, 5].

### **1.3 The dielectric properties**

The dielectric properties are the fundamental parameters that affect the propagation of the electric field. It is a measure of how electric field behaves or interacts with materials, which can be used (for example) to understand how easily an electric field will polarize a given dielectric material. Dielectric constant and loss tangent are both numerical values using which permittivity of a dielectric material can be defined. And the conductivity is the extent of electric current that flow through it. Where the conductivity is used for the rate or degree that electromagnetic wave, electricity, heat, or sound travel through a certain medium.

The dielectric properties of blood have been affected by many coefficients like blood temperature [6], applied electromagnetic wave frequency, clotting rate, human gender [7], blood group type (A, B, AB, and O) [8], blood composition, blood hematocrit level, and hemoglobin percentage [9].

#### **1.4 Blood dielectric properties measurement using open-ended coaxial probe**

The dielectric properties will be different from one material to another where these differences will enable the recognizing of the tissues by recognizing its dielectric properties [10]. This experiment attempts to improve the blood dielectric properties individually for increasing the blood appearing over other substances (perfect blood image). This microwave measurement method (experiment) has been applied in 5 GHz frequency center and in a temperature of 37°C; the blood samples with different additions and concentrations have been tested and the results have been recorded. The required experiment devices are shown in **Figure 3**.

**Figure 2.** *Fifth derivative Gaussian pulse [4].*

• Selective addressing (multiuser).

*Innovations in Ultra-WideBand Technologies*

• Low cost, low-power consumption, and low complexity.

• Low probability of interception, jamming, and resistive to a multipath problem.

• High resolution in the time domain making UWB used for location and

• Do not have any biological side effects on the human tissue (low power and

UWB medical radar naturally deals with human body tissues, which will absorb

and affect on the radiated energy of UWB pulses, so we have a challenge with increasing the radiated energy without crossing the FCC mask [1], which depends

**Gs t**ð Þ¼ **<sup>A</sup>** exp � <sup>t</sup>

and the fifth derivative of Gaussian pulses is as the following as in Eq. (2), and the frequency range of indoor application from 4 to 6 GHz introduces the best

> 10t<sup>3</sup> ffiffiffiffiffi <sup>2</sup><sup>π</sup> <sup>p</sup> <sup>ԏ</sup><sup>9</sup> <sup>þ</sup>

� �

ԏ � �<sup>2</sup> � �

> 15t ffiffiffiffiffi <sup>2</sup><sup>π</sup> <sup>p</sup> <sup>ԏ</sup><sup>7</sup>

exp � <sup>t</sup>

2 2ԏ<sup>2</sup> � � (1)

(2)

on the Gaussian pulse shape (derivative order), width, and repetition time (frequency). Here, the first derivative of Gaussian pulse equation is:

• High capacity of channel.

*Indoor power spectrum mask from FCC [1].*

• Noise-like signal.

**Figure 1.**

nonionizing).

**72**

**1.2 UWB monocycle pulses**

performance and best masking to FCC [1, 3]:

**Gs t**ð Þ¼ <sup>A</sup> � <sup>t</sup>

5 ffiffiffiffiffi <sup>2</sup><sup>π</sup> <sup>p</sup> <sup>ԏ</sup><sup>11</sup> <sup>þ</sup>

tracking applications.

The measurement system has the following components:


The permittivity equation will be as follow [11]:

$$\mathcal{E} = \frac{2\Gamma\sin\left[2s + \frac{2\pi(L\_2 - L\_1)}{\lambda}\right]}{s\left\{1 + \Gamma^2 + 2\Gamma\cos\left[2s + \frac{2\pi(L\_2 - L\_1)}{\lambda}\right]\right\}}\tag{3}$$

power absorption and related to the specific absorption rate (SAR) [12], which is measured by W/kg. The available research indicates an increase in the SAR level of whole body equals to 1 and 4 W/kg when it exposes to an electromagnetic field up to 100 kHz for about 30 min, and this increase in SAR causes an increase in the temperature of body less than 1°C [2]. Also, the animal data prove that if the SAR level is raised over than 4 W/kg, it can be out of body control and cause harmful effects of tissue heating, while epidemiological surveys are showing that no biological effects are indicated on workers or the public in the same environment [2]. The SAR level is limited by ICNIRP [2] and FCC [1]. The basic restrictions' limitation is 0.4 W/kg for the worker, 10 W/kg averaged over 10 g mass for head and spinal zones, and 0.08 W/kg for the public population. Moreover, *"*although little information is available on the relation between biological effects and peak values of pulsed fields, it is suggested that for frequencies exceeding 10 MHz, the power density as averaged over the pulse width should not exceed 1000 times the reference levels or that field strengths should not exceed 32 times the field strength

Many papers have been published by many researchers and organizations that have proposed ultra-wideband for medical applications, with different frequencies

In 2002, Staderini [14] presented biomedical applications of UWB radar as a mix of ordinary radar (ranging and detection) with spread spectrum radio which combines the two technologies. The paper talked the problem and interaction of radar wave energy with human tissues, and also the motion of internal organs of body and

reference levels*"* [13].

and hypothesis like:

**2. UWB medical application**

*Medical Application of Ultra-Wideband Technology DOI: http://dx.doi.org/10.5772/intechopen.93577*

• Breast tumor detection.

• Bone cancer detection.

• Brain hemorrhage detection.

• Noncontacting medical imaging.

• Detection of vascular pressure.

• Vital sign monitoring.

• MRI image improvement.

• Heart volume detection.

**75**

• Heartbeat and lung movement detection.

• Ultra-wideband radar for angiography.

• Blood glucose concentration level measurement.

Some of these researches are mentioned below:

• Position and localization.

where λ is the wavelength, Γ is the reflection coefficient, and s is standing wave ratio.

#### **1.5 Safety aspects for the human tissue that exposed to UWB**

The use of UWB electromagnetic wave spectrum in medical application that penetrates human body tissue makes a challenge with the patient safety (safe exposure). On the other hand, because its band is 3.1–10.6 GHz, the major effects of UWB using on the human tissue are the thermal effects. These effects are caused by

**Figure 3.** *Blood dielectric properties measurement system.*

*Medical Application of Ultra-Wideband Technology DOI: http://dx.doi.org/10.5772/intechopen.93577*

The measurement system has the following components:

• Open-ended coaxial probe (model: 85070E performance probe).

<sup>Ԑ</sup> <sup>¼</sup> **<sup>2</sup>***<sup>Γ</sup>* **sin** <sup>½</sup>**2***<sup>s</sup>* <sup>þ</sup> **<sup>2</sup>***π*ð Þ *<sup>L</sup>***2**�*L***<sup>1</sup>**

**1.5 Safety aspects for the human tissue that exposed to UWB**

*<sup>s</sup>* **<sup>1</sup>** <sup>þ</sup> *<sup>Γ</sup>***<sup>2</sup>** <sup>þ</sup> **<sup>2</sup>***<sup>Γ</sup>* **cos 2***<sup>s</sup>* <sup>þ</sup> **<sup>2</sup>***π*ð Þ *<sup>L</sup>***2**�*L***<sup>1</sup>**

where λ is the wavelength, Γ is the reflection coefficient, and s is standing wave

The use of UWB electromagnetic wave spectrum in medical application that penetrates human body tissue makes a challenge with the patient safety (safe exposure). On the other hand, because its band is 3.1–10.6 GHz, the major effects of UWB using on the human tissue are the thermal effects. These effects are caused by

*λ*

*λ* n � h i (3)

ENA series).

• Water bath and thermistor.

*Innovations in Ultra-WideBand Technologies*

• Glass sample containers and alcohol wipes.

The permittivity equation will be as follow [11]:

• Adjustable probe stand.

• PC computer (laptop).

ratio.

**Figure 3.**

**74**

*Blood dielectric properties measurement system.*

• RF vector network analyzer (compatible with the above probe model: E5063A

power absorption and related to the specific absorption rate (SAR) [12], which is measured by W/kg. The available research indicates an increase in the SAR level of whole body equals to 1 and 4 W/kg when it exposes to an electromagnetic field up to 100 kHz for about 30 min, and this increase in SAR causes an increase in the temperature of body less than 1°C [2]. Also, the animal data prove that if the SAR level is raised over than 4 W/kg, it can be out of body control and cause harmful effects of tissue heating, while epidemiological surveys are showing that no biological effects are indicated on workers or the public in the same environment [2].

The SAR level is limited by ICNIRP [2] and FCC [1]. The basic restrictions' limitation is 0.4 W/kg for the worker, 10 W/kg averaged over 10 g mass for head and spinal zones, and 0.08 W/kg for the public population. Moreover, *"*although little information is available on the relation between biological effects and peak values of pulsed fields, it is suggested that for frequencies exceeding 10 MHz, the power density as averaged over the pulse width should not exceed 1000 times the reference levels or that field strengths should not exceed 32 times the field strength reference levels*"* [13].
