Dual Resonant Wearable Metamaterial for Medical Applications

Abstract

A dual band textile wearable metamaterial is designed and fabricated as a ground plane for dual resonant wearable antennas at the Industrial-Scientific-Medical (ISM) frequency band for the applications of RadioFrequency-Identification (RFID) and Wireless-Local-Area-Network (WLAN). The proposed Metamaterial has zero-degree reflection coefficient phases at 0.9 and 2.4 GHz to reflect the backward radiations of the antenna incident waves upward, thus maximizing the gain out of the body and minimizing the risk of exposure into it. The radiation patterns, front-to-back ratio of the antenna with and without metamaterial and the reflection coefficient S11 of the dual resonant structure on different body loadings are investigated. The effect of bending on the performance of the proposed integrated structure has been measured. The limitation of the interacted electromagnetic waves with a heterogeneous voxel model has been analyzed using the specific energy absorption rate (SAR). The measured S11 values of the proposed structure on the human hand have showed an excellent agreement with the simulation over inhomogeneous phantom. The proposed structure has exhibited insignificant shift in resonant frequencies and return loss values at different bending angles. The proposed dual band metamaterial-backed antenna revealed a gain of 6.5 dBi, a front-to-back ratio of 12.5 dB and 10g-based SAR results less by 94% than the metallic reflector-backed antenna when both are placed over the same hand voxel model.