Design and Implementation of a Compact Wideband Wearable Antenna for ISM/WiMAX/WiFi/5G Band Body-Centric Wireless Applications

In this work, we propose a compact, wideband, and wearable microstrip patch antenna with a defected ground structure (DGS) for body-centric wireless applications. The proposed antenna, consists of an isosceles triangle with four parallel rectangular shaped flat bars, is designed and optimized in CST studio suite using low-cost FR-4 as the substrate with a height of 1.6 mm, relative permittivity of 4.3 and loss tangent of 0.025, followed by prototyping. The net geometry of the antenna is 35  25  1.6 mm3. A microstrip feed line is used to excite the antenna while rectangular slots on the antenna and partial grounding planes are used for improving the bandwidth. The designed antenna operates over a wide frequency range of 2.6 to 6.8 GHz which satisfy for the popular lower 5G, WiMAX, WiFi, and ISM band applications. The antenna resonates at of 3.5 GHz and 5.95 GHz, and maintains improved reflection coefficient, wide bandwidth, positive gain and efficiency over the operating frequency range. The on-body analysis of the simulation results available in CST has also been performed which shows reasonable results. The specific absorption rate (SAR) analysis is accomplished separately at each resonant peak frequency over a human body phantom model and the maximum SAR values obtained are 0.4137 W/kg at 3.5 GHz and 0.4062 W/kg 5.95 GHz for 1 gm of biological tissue which satisfy the IEEE recommended safety limit of 1.6 W/kg. A prototype of the proposed antenna is fabricated and the measured results of return loss shows good agreement with the simulated one. The combined features of new design, compact size, wideband performance, multiband support, improved reflection coefficient, positive gain and efficiency, and low SAR value contribute to the antenna's novelty, making the antenna a significant advancement in the field of wireless communication and biomedical applications.