*1.1.3 Conductive materials*

Conductive materials may be pure metallic materials or electro-textile materials. The pure metallic material is pasted on the dielectric substrate which is made out of different materials such as: copper, gold and etc. The electro-textile materials are conductive fabrics [9].

## **1.2 Antenna design**

In general, to design any rectangular wearable microstrip patch antenna should be considered the following parameters such as dielectric constant (*εr*), resonant frequency (*fo*), and height of the substrate (*h*) for calculating the length and the width of the patch [10].

## **1.3 Antenna simulation**

There are several technologies and simulators for analysis and simulation the wearable antennas. CST MICROWAVE STUDIO is a computer system technology and is a numerical simulator which uses the finite integration technique (FIT) [11].

## **1.4 Performance near human**

Generally, wearable antenna or body-worn antenna radiates the electromagnetic waves (EMWs) which are absorbed by tissues of the human body. The

**53**

**Figure 2.**

*Fractal Antennas for Wearable Applications DOI: http://dx.doi.org/10.5772/intechopen.81503*

used and etc. in [15, 16].

shown in **Figure 2** [21]:

1.Emergency workers outfits.

2.Medical applications.

4.Military applications.

5.Sports outfits and so forth.

*The various applications of the wearable antenna [21].*

3.Space applications.

*1.4.1 The SAR safety limitation*

replaced by antenna with a lower back radiation [18].

**1.5 Applications of wearable microstrip antenna**

absorption of these waves will cause damage and burn human tissues [12]. So that it is necessary to decrease the electromagnetic energy interaction towards the human body tissue from the wearable antennas when in use [13]. The absorption of the electromagnetic waves (EMWs) from the human tissue is measured by the specific absorption rate (SAR) [14]. Therefore, the SAR value plays a vital role in any design of wearable antenna. There are some parameters which will effect on the SAR value such as: size, shape, location, radiated power and type of antenna

The SAR safety limit is based on the standardization committee and is various in different regions in over the world. In the US is regulated by the Federal Communications Commission (FCC) where the acceptable maximum SAR value 1.6 W/kg, averaged over 1 gram of tissue [17]. But in Europe, the acceptable maximum SAR value is 2.0 W/kg averaged over 10 grams of tissue which is regulated by the International Commission on Non–Ionizing Radiation Protection (ICNIPR) [17]. If the SAR value exceeds the safety limit, the antenna must be changed and

The development of antenna technology for human and machine interface has made qualitative leaps in the use of textiles as antenna substrates [19]. In future, this will permit freedom to design antenna systems worn by the body and integrated into it so; these are called "smart clothes" [20]. They will emerge in various as

### *Fractal Antennas for Wearable Applications DOI: http://dx.doi.org/10.5772/intechopen.81503*

*Fractal Analysis*

**1.1 Wearable antennas design steps**

*The different geometries of fractals in natural [6].*

The fabrication process of flexible and wearable antennas depends mainly on the materials involved in the designed structure. Properties of conductive and dielectric materials used in flexible and wearable antennas, are surveyed in this section [7].

Dielectric materials that are used as substrates for antennas, these materials may be inflexible such as conventional soft PCB or flexible such as textile material in clothing. The textile materials must be it is flexible, easy to design, water resistant

Conductive materials may be pure metallic materials or electro-textile materials. The pure metallic material is pasted on the dielectric substrate which is made out of different materials such as: copper, gold and etc. The electro-textile materials are

In general, to design any rectangular wearable microstrip patch antenna should be considered the following parameters such as dielectric constant (*εr*), resonant frequency (*fo*), and height of the substrate (*h*) for calculating the length and the

There are several technologies and simulators for analysis and simulation the wearable antennas. CST MICROWAVE STUDIO is a computer system technology and is a numerical simulator which uses the finite integration technique (FIT) [11].

Generally, wearable antenna or body-worn antenna radiates the electromagnetic waves (EMWs) which are absorbed by tissues of the human body. The

and light in weight to make the wearable antenna more suitable [8].

*1.1.1 Material selection*

**Figure 1.**

*1.1.2 Dielectric materials*

*1.1.3 Conductive materials*

conductive fabrics [9].

width of the patch [10].

**1.3 Antenna simulation**

**1.4 Performance near human**

**1.2 Antenna design**

**52**

absorption of these waves will cause damage and burn human tissues [12]. So that it is necessary to decrease the electromagnetic energy interaction towards the human body tissue from the wearable antennas when in use [13]. The absorption of the electromagnetic waves (EMWs) from the human tissue is measured by the specific absorption rate (SAR) [14]. Therefore, the SAR value plays a vital role in any design of wearable antenna. There are some parameters which will effect on the SAR value such as: size, shape, location, radiated power and type of antenna used and etc. in [15, 16].
