Abstract: A circularly polarized antenna with large axial ratio bandwidth has been proposed in this work. The antenna is designed by a 45o slot cut and a circular opening in the center of the square patch anda square metallic ring around it. It can achieve a 3-dB axial ratio Bandwidth of 110 MHz with impedance B.W of 56 MHz as compared to the antenna without a metal square ring is 35MHz.This antenna can be successfully applied for wireless application.

Keywords: Microstrip Antenna, Axial ratio bandwidth, return loss, circular polarization.