**6. Wearable metamaterial antennas for communication, healthcare, and IoT systems**

The antenna's electrical parameters performance near the human body were computed by employing the antenna and human body model presented in **Figure 16a**. The dielectric constant and conductivity of human body tissues are given in **Table 7** [21, 22]. The effect of the antenna location on the human body is simulated by evaluating the antenna's electrical parameters on human body. The variation of the

*Green Wearable Sensors for Medical, Energy Harvesting, Communication, and IoT Systems DOI: http://dx.doi.org/10.5772/intechopen.112352*

**Figure 16.**

*(a) Model of wearable antenna environment; (b) wearable medical system on human body.*

dielectric constant of the body tissues affects the electrical performance of the antenna. The antenna resonant frequency may be shifted up to 10% at different locations of the antenna on the patient's body. As shown in **Table 7**, the dielectric constant of fat tissues is 4.7, 41 in the skin tissues, 43 in the stomach area, and up to 128.1 in the small intestine tissues. The antennas may be placed inside a belt, as shown in **Figure 16b**. The antenna's electrical characteristics were computed and measured for air spacing between the sensors and human body up to 25 mm at different locations on the human body. Measurements of wearable sensors and antennas are done by using a phantom with sugar, salt, and water that represent the dielectric constant and conductivity of human body tissues [2–5, 19]. The antenna's electrical and mechanical characteristics were optimized to achieve the best antenna electrical and mechanical performance. Wearable antennas and sensors measurements and setup are discussed in [2–5, 19].


#### **Table 7.**

*Electrical parameters of human body tissues [16, 17].*


**Table 8.**

*Measured harvester efficiency as function of input collected power.*

**Table 2** presents a comparison between computed and measured results of sensors without and with CSRR. **Table 8** presents a comparison of computed and measured results of compact wearable antennas.

**Tables 2** and **8** verify that there is a good match between computed and measured results. Electrical performance of several passive and active antennas (such as dipoles, loop, slot and other antennas) is discussed in [2–6]. Medical, wearable wireless BAN, IoT, and monitoring systems with wearable BAN systems are shown in **Figure 17**. Hospitals, Health care centers and medical staff can be contacted from everywhere at any given time.

*Green Wearable Sensors for Medical, Energy Harvesting, Communication, and IoT Systems DOI: http://dx.doi.org/10.5772/intechopen.112352*

**Figure 17.**

*Green medical, WWBAN, and IoT monitoring system with WBAN networks with energy harvesting units.*
