An Ultralow SAR SIW Cavity-Backed Textile Antenna and Its SAR Measurements for On- and Off-Body Applications

This study introduces a cavity-backed textile antenna based on a substrate integrated waveguide (SIW) featuring an ultra-low specific absorption rate (SAR) for both on-body and off-body applications within the 2.45 GHz ISM band. The Giuseppe Peano fractal slot is used in SIW cavity-backed configuration to provide good isolation between the body and the antenna. The measured results depicted strong consistency with the numerical simulation. The measured gains in the on-body and the free-space are 3.6 dBi and 3.9 dBi, respectively. The free space measurement confirms a high radiation efficiency in the case of textile antenna and front-to-back ratio (FTBR) of 69% and 20.6 dB, respectively. Comparison between simulated and measured SAR distribution confirms that for an input power of 500 mW, the average maximum absorption rate in the human body was 0.0347 W/kg over 1 g of tissue and 0.0177 W/kg over 10 g of tissue. The maximum SAR results reported here are significantly lower than the previous SIW textile antennas and confirm the excellent performance of the on and off-body applications.