Omnidirectional Dual-Band Dual Circularly Polarized Microstrip Antenna with Wide Axial-Ratio Beamwidth

Abstract

A dual-band dual circularly polarized (CP) omnidirectional antenna is proposed in this paper. Antennas are based on square patches and curved branches. CP antenna is a simple single-layer structure, which generates horizontal and vertical polarization components through patch and shorted probes. Antennas produce left-hand circularly polarized (LHCP) and right-hand circularly polarized (RHCP) in low and high frequency bands, respectively. On the H-plane, the simulated gain of low frequency and high frequency is 1.63 dBi and 0.95 dBi, respectively. The antenna operates at 1.83 GHz and 3.5 GHz and exhibits the 3 dB axial ratio beamwidth of more than 120 degrees in the E-plane at both resonant bands.