A Compact AMC-Backed Meander Line Antenna With Low SAR and High Gain for Wearable ISM Band Applications

This paper introduces an innovative meander line antenna structure supported by a compact Artificial Magnetic Conductor (AMC) for wearable applications operating in the 2.4 GHz Industrial, Scientific, and Medical (ISM) band. The proposed antenna features a low profile, high directivity, low specific absorption rate (SAR), and robustness to body loading. An AMC design achieving 59 % size reduction compared to previously reported configurations is proposed. Despite the AMC's compact size of only 43×43×2.4 mm³, the antenna's performance is significantly improved. The integrated design maintains effective performance under deformation and body loading, offering a wide bandwidth that mitigates frequency detuning issues. The integrated design achieves a gain of 7.81 dBi, a bandwidth of 13.8% (2.341 GHz- 2.671GHz), an efficiency of 85.4%, and a front-to-back ratio (FBR) of 16.2 dB. The SAR analysis shows over 95% reduction as compared to the meander line alone, even at high input power levels of 1 W with direct skin contact. Furthermore, the proposed design outperforms all existing designs listed in Table 1 in terms of compactness, front to back ration and efficiency, while yielding competitive gain and bandwidth, making it as a leading solution and strong candidate for wearable ISM band applications.