Wireless Body Area Network (WBAN) technology is gaining popularity in personal communication due to the expanding improvement in wireless technology. Wearable antennas are utilized in various WBAN applications including personal healthcare, entertainment, military, and many more due to their attractive characteristics and the potential for integrating lightweight, compact, low-cost, and adaptable wireless communications. A wearable reconfigurable antenna will allow a single antenna to operate at multiple resonant frequencies, radiation, polarization or hybrid between them, by using single or multiple active switching devices for signal transmission and reception in different parts of human body, rather than using multiple antennas. Over the years, several review papers were reported on wearable antennas which discussed the requirements and issues of wearable antennas in terms of their design, fabrication, and measurement. Nowadays, WBAN technology employs a single wearable reconfigurable antenna to perform multiple functions in different parts of human body. Recently, a significant amount of work has been carried out in the area of wearable reconfigurable antennas for WBAN applications. This paper presents a comprehensive review of the requirements and analysis needed for wearable reconfigurable antennas such as Specific Absorption Rate (SAR) for on-body analysis, investigation of the antennas in bending conditions, reconfigurable techniques and reconfigurable performance metrics.

No abstract

The design and analysis of a compact dual-band wearable antenna for WBAN applications is presented. The antenna was prototyped on a semi-flexible Rogers Duroid RO3003™ with compact dimensions of 41 × 44 mm 2 which corresponds to 0.33 λ0 × 0.35 λ0, where λ0 is the free space wavelength at 2.4 GHz. The antenna is designed in the preliminary stage to resonate at 5.8 GHz. An inverted U-shaped slot is added to the patch to create one more resonant frequency at 2.4 GHz. In order to enhance the antenna's bandwidth and gain, two slots at the patch's bottom edge and a partial ground are added. The measured percentage of impedance bandwidth at 2.4 GHz and 5.8 GHz are 3.75% and 5.17%, respectively. The gain is measured to be 3.74 dBi and 5.13 dBi and the efficiency is 91.4% and 92.3%, respectively at the operating bands. The measured radiation patterns exhibit a bidirectional and directional radiation pattern in the E-plane at 2.4 GHz and 5.8 GHz bands, while omnidirectional radiation patterns are observed in the H-plane. At 2.4 GHz, the SAR limits are simulated to be 0.955 W/kg and 0.571 W/kg for 1 g and 10 g of human tissue, while at 5.8 GHz, the SAR limits are 0.478 W/kg and 0.127 W/kg, respectively. Therefore, the proposed antenna has met the FCC and ICNIRP standards. Bending conditions and on-body measurements of the proposed antenna indicate that the antenna's performance is unaffected. As a result, it is shown that the antenna possessed the ability to be utilized in WBAN applications.INDEX TERMS Dual-band, patch antenna, WBAN applications, SAR, bending condition.