A Triple-Band Uni-Cavity Fabry–Perot Cavity Antenna With Hybrid Excitation Modes

Abstract

A novel methodology realizing multiband Fabry-Perot-Cavity Antenna (FPCA) is proposed. Different from single transmission-mode (T-mode) or reflection-mode (R-mode) FPCA, the R+T-mode FPCA employs hybrid excitation modes to the same FPC, reducing the requirement for multiband high-quality feed antennas. To verify this methodology, a triple-band FPCA integrated by two R-mode ones, operating at the middle and the high bands, and a T-mode one working at the low band is designed. A triband partially-reflective-surface (PRS) offering bidirectional asymmetric transmission for middle and high bands, and partial reflection for the low band, is proposed. Meanwhile, a triband artificial magnetic conductor is designed to fulfill the in-phase bouncing condition in a low-profile uni-cavity for all bands. One inter-cavity feed and two external ones are utilized to complete the hybrid excitation of the FP cavity. Finally, a proof-of-concept prototype is fabricated showing -3 dB gain bandwidths of 7.0% (3.02-3.24 GHz), 16.9% (5.38-6.37 GHz), and 10.0% (10.31-11.40 GHz). Beam-scanning ranges of ±35° and ±30° are also obtained for the middle and the high bands. The proposed methodology may readily realize an FPCA of even more frequency bands with limited aperture size and a low-profile resonant cavity.