Analysis of a Compact UWB Antenna with Integrated Dual-Band Notch Features for Wireless Body Area Network Applications

Abstract

This paper presents an analysis of a compact dual-band ultra-wideband (UWB) antenna designed for Wireless Body Area Network (WBAN) applications. The antenna operates between 3.2 GHz and 13.7 GHz with two notched frequencies using H and U slots on the patch and feedline, respectively, at 5.4-5.6 GHz for notching Wi-Fi/ISM and 6.5 GHz - 8.2 GHz for notching. The antenna's dimensions were optimized using a genetic algorithm embedded in the HFSS and CST software to achieve a compact size of 26 mm × 27 mm in a semi-circular shape with a radius of 12 mm. The specific absorption rate (SAR) level from the antenna was reduced by using a defected ground structure (DGS) and rectangular slots. The performance of the antenna was evaluated based on some important metric used for analyzing antenna performance. The simulation results show that the antenna achieved a return loss of -10 dB within 3.2 GHz to 13.7 GHz with a gain of 5 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. Furthermore, the antenna has good 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.