Towards durable and efficient antenna with SAR reduction analysis for on-body applications

Abstract

Abstract This paper is focused on providing a viable solution to wearable antenna performance disconcertment caused by the underlying human body. Direct placement of the antenna on the body yields undesired results owing to the frequency detuning effect. The simplest possible way out is to make use of a metallic reflector. Hence, a reflector backed antenna is presented for 5.8 GHz ISM band with total lateral dimensions of 28 × 28 × 13.58 mm3. The reflector makes use of a conformal high dielectric laminate coated with a thin copper layer owing to which the assembled design achieves low SAR (Specific Absorption Rate). The prototype provides excellent results at the cost of some extra volume occupation in an off-body direction. Another AMC (Artificial Magnetic Conductor) backed technique is followed and implemented separately to have the structural compactness lacking in the former case. The antenna at hand is backed by a 2 × 2 array of AMC unit cells. The overall design dimensions are reduced. The reflector backed design achieves 8.2 dB gain, above 90% efficiency, and 99% bandwidth overlap with the primary antenna. The AMC backed design provides good spectrum coverage from 5.73 to 5.94 GHz with high gain. Free space response, on-body performance, and investigation of SAR analysis of the proposed designs substantiate effective wireless data transfer in body-centric communication.