Single-layer single-feed bidirectional radiated circularly polarized ‘G’-shaped microstrip-line antenna

A single-layer single-feed bidirectional radiated circularly polarized `G'-shaped microstrip-line antenna is proposed. The `G'-shaped microstrip-line is composed of multi segments for good matching and pure circular polarization. Moreover, a semi circle arc shaped ground is used to obtain no tilted radiation pattern. Simulations show that the antenna has 10-dB return loss bandwidth of 9%, 3-dB axial-ratio bandwidth of 11% and beamwidth of 60
^o
, and the gain is larger than 3.6 dBic over the band from 4.4 GHz to 5 GHz.