Gain enhancement of a compact thin flexible reflector-based asymmetric meander line antenna with low SAR

Abstract

A compact, flexible, coplanar waveguide-fed, U-shaped reflector surrounded asymmetric meander line antenna operating at 2.4.GHz is presented for wrist wearable applications. The antenna is printed on flexible Rogers Ultralam 3850 substrate. Size reduction of 67.7% was attained by employing the meandering methodology, in comparison with the printed straight monopole. The design displays a gain of around 3.dB by incorporating a U-shaped reflector, on the same level as the radiator, which is considered as the main contribution of the proposed design. Bending scenarios were studied proving the antenna robustness against bending. The proposed antenna was bent over a human body model with optimum separation distance, where enhancement of the specific absorption rate (SAR) level has been achieved, compared to the symmetric meander line antenna. The antenna was fabricated and measured where a high agreement was met in terms of simulated and measured return loss and radiation pattern polar plots, as well as, simulated and measured gain.