Wideband Design of A Circularly Polarized Fabry-Perot Cavity Antenna

A novel design of Fabry-Perot cavity antenna (FPCA) is proposed to achieve circularly polarized (CP) radiation over a wide axial ratio (AR) bandwidth. Degenerate orthogonal modes of a square-shaped slotted patch are excited by using the dual-offset feeding technique and the patch has been used as a primary radiator of the proposed CP-FPCA. An approximate gain improvement of 7–11 dB is achieved just by using a specially engineered superstrate which consists of strategic square patches. The boresight gain of the antenna varies between 11.5-16.2 dBi over its 25% matching as well as AR-bandwidth. The AR value remains below 1 dB over the operating bandwidth and has a 25° AR-beamwidth. Estimated values of boresight cross-pol and sidelobe levels are below −27dB and −8dB, respectively.