An Optimized Feed Hexagonal Antenna with Defective Ground Plane for UWB Body Area Network Application

Abstract

Body area network has facilitated monitoring, authentication and security through sensors or microstrip antenna with specified frequency. The purpose of this research work is to propose a simplified way to search for an optimal length of the inset for edge feeding using the Evolutionary Algorithm search by minimizing the reflection coefficient using ANSYS HFSS. The optimal inset length resulted in an antenna with better radiation efficiency and wider bandwidth. The antenna structure is 70x70x1.6 mm3, with a modified ground. The purpose of this antenna is communication in Ultra-wideband and works in 5.4, 8.1, and 9.8 GHz bands respectively. The resonant bandwidth measured are 1.02, 0.28, 0.12 GHz, respectively. Simultaneously the achievable gains are 3.18, 7.81, and 19.95 dB, respectively in free space. As the antenna is of wearable type, the front-to-back ratio evaluated for each band is 2.31, 7.01, and 13.91 respectively. The results of the fabricated antenna agree with the simulated results. The specific absorption rates at resonant frequencies were observed to be 0.3, 0.56 and 0.24 W/kg respectively when antenna is placed on a human tissue model. The antenna is useful for on-body communication at ISM band, and high data rate off-body communication in body area networks.