Wideband Circularly Polarized Fabry-Perot Antenna [Antenna Applications Corner]

A broadband and high-gain, circularly polarized Fabry-Perot (CPFP) antenna is presented in this article. This antenna employs a two-layer partially reflective surface (PRS) with positive reflective phase gradient, which can improve the 3-dB gain bandwidth of Fabry-Perot (FP) antennas effectively. To generate a circularly polarized (CP) wave, a wideband CP microstrip patch is designed to serve as the feeding source. To validate this concept, an antenna prototype at X band is fabricated. The measurement results show that this antenna achieves a 3-dB gain bandwidth of 28.3% from 8.8 to 11.7 GHz with the peak gain of 14.7 dBi. Within this frequency range, the axial ratio (AR) is below 3 dB and the reflection coefficient is lower than -10 dB.