SAR Improvement through AMC Adapted Duplex-band Duplex-polarized Body-worn Textile Antenna

This paper proposes an optimized design for an artificial magnetic conductor (AMC) plane assimilated body-worn textile antenna that significantly improves the duplex-band resonant frequency behavior and reduces backward radiation i.e. specific absorption rate (SAR). Duplex polarization behavior with an optimal dual frequency in terms of 1.47 GHz for Global Positioning System (GPS) and 2.15 GHz for Wireless Body Area Network (WBAN)/ Wireless Local Area Network (WLAN) system is achieved which is a significant improvement over the existing dual-band dual-sense textile antennas that use 1.575 GHz and 2.45 GHz frequency, respectively. Here, a 3×3 layout with a square patch unit cell is considered to design the AMC plane that contains four square slits and a square ring in each square patch unit cell. A substrate exists between the AMC plane and the square-shaped radiator on the peak of the proposed antenna. Two opposite corners of the radiator patch are curtailed to achieve duplex band and duplex polarization (linear and circular) characteristics, which are performed by adding asymmetrical rectangular slits on each corner of the square patch radiator. The proposed body-worn textile antenna was tested using a human voxel model CST Microwave Studio simulation environment. The simulation results exhibit significant improvement in SAR values with approximately 4⁓8% decrement for lower frequency values and 6⁓15% decrement for upper-frequency values in comparison with the existing methods considering 1 gm and 10 gm tissue of the human body model. This study could open up new design strategies for minimizing the SAR values for conventional body-worn antennas that are much lower than the internationally recognized regulatory level of SAR 1.6 W/Kg & 4 W/Kg for 1 gm and 10 gm human body tissues respectively.