Compact Circularly Polarized Crossed Dipole Antenna with Wide Bandwidth and Wide Axial Ratio

Abstract

A compact circularly polarized (CP) crossed dipole antenna with wide bandwidth and wide axial ratio (AR) is proposed. The proposed antenna consists of a pair of crossed dipoles, a double three-quarter rings with a 90° phase shift, four split rings resonator and four parasitic patches. The combination of the crossed dipole with a three-quarter ring can produce an AR point. It is found that the introduction of four split rings resonator on both surfaces of the substrate can increase the bandwidth, make the structure compact, and can produce an AR point at high frequency. The parasitic patch around the split ring resonant produces perturbation that combines the two AR points and introduces a new AR point. The ultimate simulation results show that the proposed antenna has a 10 dB impedance bandwidth of 69.6° (1.35-2.79 GHz) and a 3 dB AR bandwidth of 58.5% (1.4-2.56 GHz). In addition, it has a stable gain in the whole CP frequency region.