Design and Analysis of Compact Diversity Antenna for Wearable Applications

Abstract

Abstract A new compact Ultra-Wideband (UWB) antenna is designed for wearable applications using jeans fabric as the substrate. The proposed antenna has an impedance bandwidth from 3.1 to 11.1 GHz. The antenna footprint is of size 18mm x 26 mm, and the thickness of the substrate is 0.8mm. It is based on a simple patch antenna configuration where the radiator consists of a simple rectangular structure and an ellipse added on top. Circular and elliptical notches are removed from the radiator, and rectangular notches are removed from the feed line for bandwidth enhancement. A partial ground plane of size 18mm x 9mm with a square notch is present on the other side of the antenna. Two such antennas are placed side by side as unit cells, one horizontal and the other vertical, to obtain a 2-port diversity set. The unit cells are placed at a distance such that minimal mutual coupling is present between the cells, and the size is also not compromised. The final diversity set so obtained is of size 44mm x 26 mm. The simulation results for reflection coefficients, SAR, and radiation pattern for both unit cell and diversity port are presented. Diversity parameters like ECC and diversity gain are also simulated for diversity antenna. The results obtained by testing the fabricated prototype are found to be matching reasonably with the simulated results. The antenna is also subjected to bending analysis.