NOVEL HIGH-GAIN COUPLED MICROSTRIP LINE-FED CIRCULARLY POLARIZED MICROSTRIP ANTENNA WITH LOW PROFILE

摘要

A novel high-gain circularly polarized microstrip antenna fed by a coupled microstrip line (CMS) is presented. The circularly polarized radiation is excited by a pair of side-concave patches. Two identical patches are combined and fed by CMS. The simulated maximum gain is 9.5 dB and minimum axial ratio (AR) is 0.3 dB both at the center frequency of 5.8 GHz. A 180° phase shifter balun is designed to measure the antenna. Simulation and experiment results have good agreement. The measured bandwidth of return loss below -10 dB is 160 MHz. The maximum gain and minimum AR is 9.7 and 1.0 dB, respectively. The bandwidth of AR less than 3 dB is about 80 MHz. This antenna is characterized by low profile and high gain. It can be used as the receiving antenna in microwave power transmission and other communication systems.