Design and equivalent circuit analysis of textile antenna for WLAN and WBAN application

In this paper a textile antenna with circular polarization for WBAN in ISM band applications is designed and its corresponding equivalent circuit analysis is done at 2.45 GHz. The circular polarization provides better power reception in whatever the direction body worn antenna turns. For achieving the circular polarization, a rectangular slot of 45° at the center of the circular patch is used. In the ground plane a rectangular cross slot is introduced for improving the bandwidth. The simulation result shows that the antenna has an impedance bandwidth of 110 MHz and the gain of the antenna is 3.6 dB. The designed antenna is fabricated on the textile substrate where copper tape is used as the conductive material for the patch and the ground plane. The measured operating frequency range of antenna spans from 2.40 GHz to 2.51 GHz having a gain of 3.6 dB at 2.45 GHz. Simplified lumped element circuit model of the textile antenna has been derived and simulation is done using CST software. The antenna is tested by bending it above a foam sheet and the performance of the antenna is studied with respect to return loss, axial ratio, radiation pattern and gain in order to account for its usefulness in the WBAN applications. Many previous researches regarding textile antenna using different substrates including jeans substrate have been done, this paper mainly contributes to the practical and mathematical analysis of previous works and comparing the results.