A Soft Surface Based Low Profile Wearable Antenna for Biomedical Telemetry

Abstract

A soft surface based low profile wearable antenna operating on 5.8 GHz Industrial, Scientific and Medical (ISM) band (5.725-5.875 GHz) is presented for high speed biomedical telemetry. The flexible substrate of Ethylene-Vinyl Acetate (EVA) foam makes the structure water proof, ultra-violet resistant and mechanically stable. First, the basic antenna structure (reference) with inset feeding is designed. Initially, the forward to back power ratio obtained is 14.1 for basic design. The back radiation is further reduced by introducing soft surface around the patch. Use of two different materials as soft surface has been studied and analyzed. The maximum gain of 5.2 dBi and Front to Back Ratio (FTBR) of 25.63 is achieved for the chosen resonant frequency. The absorption of electromagnetic field by the body is reduced by 9.35 % and gain is improved by 23.68/24.40 % with reference to our basic design of antenna without soft surface. The value of Specific Absorption Rate (SAR) is 1.26 W/kg for 10 gm of human body tissue which is within the specified limits. The software simulated and experimented results are presented.