Enhance gain and bandwidth of circularly polarized microstrip patch antenna using gap-coupled method

Abstract

In this paper, one 3 × 3 and one 5 × 5 antenna arrays are studied. In each array, one probe-fed circularly polarized (CP) microstrip patch antenna is placed at the center as the driven antenna and is gapped coupled to the remaining elements. It is investigated that CP performance of the patch can be proved by properly arranging these parasitic elements. The driven patch is a perturbed square one with two diagonal corners truncated. The remaining elements are square patches slightly smaller than the driven patch. The proposed antennas have been constructed and measured. The 3 × 3 array has a measured gain of 7.7dBic with a 3dB axial ratio bandwidth of 3.3%. The 5 × 5 array has a measured gain of 9.3dBic with a 3dB axial ratio bandwidth of 8.1%.