Hybrid Perturbation Technique Applied to Stacked Patches for Circular Polarization

In this paper, a wideband circularly polarized (CP) stacked microstrip antenna is presented. CP is achieved by using hybrid perturbation technique, where positive perturbations are applied to the driven patch and negative perturbations to the parasitic patch. The axial ratio bandwidth achieved is wider than that from typical CP patch antennas. The antenna is excited by a probe-feed without requiring any complex dual feed network to generate two equal and orthogonal modes necessary for the CP generation. This reduces the system complexity and saves space in the antenna in comparison to those with dual feeds. The antenna exhibits a simulated impedance bandwidth of (for S11=-10 dB) 10.4%, and axial ratio (AR ~ 3 dB) bandwidth of 2.8%. The antenna demonstrates broad axial ratio beamwidth in both planes which is useful for wide angular coverage.