High-gain wideband circularly polarized stacked microstrip antennas with single microstrip feeds and short horns

A single feed system is developed to improve the axial ratio bandwidth of circularly polarized rectangular stacked microstrip antennas (CPSMAs) to about 18% by optimizing the feed location and a few other parameters. A main radiator and a parasitic patch of identical size are considered and the separation between them and location of the feed has been optimized to achieve a good AR bandwidth and minimum AR value. For improving the gain of antenna, surface mounted short horn (SMSH) has been used on the CPSMA. The structure has the directive gain of more than the 10dBic over the impedance bandwidth and a 3dB AR bandwidth of 18.8%. The 10dB return-loss bandwidth is 29.6%. The proposed feed system is very useful for rapid design of circularly polarized stacked microstrip antennas with high gain and large AR bandwidth and also very useful to design high gain and wide band microstrip antennas.