A new method for broadening bandwidths of circular polarized microstrip antennas by using DGS & parasitic split-ring resonators

Abstract

A new method for broadening the impedance and the axialratio (AR) bandwidths of circular polarized microstrip antennas (CPMAs) is proposed. It has improved the bandwidths of a reference antenna greatly without enlarging the antenna size or deteriorating circular polarized radiation characteristics by placing four sequentially rotated parasitic split-ring resonators (SRRs) around the patch of the reference antenna and embedding four defeated ground structure (DGS) elements on the ground plane. Improvements of 51.3% and 49.8% in the impedance and the axial-ratio bandwidths of the antenna are achieved in simulation, respectively. The simulated -10 dB impedance and 3 dB axial-ratio bandwidths of the antenna have been improved from 101.1MHz (4.12%) to 153.0MHz (6.26%) and from 25.1MHz (1.02%) to 37.6MHz (1.54%).