Analysis of a Compact UWB Antenna with Integrated Band-Notched Feature for Wireless Body Area Network Applications

Abstract

This paper presents an analysis of a compact band-notched ultra-wideband antenna intended for Wireless Body Area Network applications. The antenna operates between 3.4 GHz and 12.9 GHz with notched frequency using H and U slots on the patch and feedline for notching 6.5 GHz – 7.9 GHz band. By employing a genetic algorithm, the antenna dimensions were refined to obtain a compact semi-circular configuration with overall dimensions of 26 mm × 27 mm and a 12 mm radius. A reduction in the specific absorption rate was achieved by integrating a defected ground structure along with rectangular slots into the antenna design. The antenna performance was assessed using several key antenna parameters. According to the simulation outcomes, the antenna achieves a return loss below −10 dB from 3.4 GHz to 12.9 GHz and provides an average gain of 6.4 dBi. Also, the developed antenna showed a significant improvement in SAR reduction to a level of 0.8 W/kg averaged over one gram of tissue, which is within the safe limits of the Federal Communications Commission (FCC) for low-power devices and therefore suitable for WBAN applications. In addition, the antenna demonstrates effective impedance matching. The average Poynting value of 4.09 W/m2, which is evenly distributed over the patch and the feedline of the antenna, revealed a uniform radiated power density of the antenna. This value is 29.5% less than the safe limit announced by the FCC.