Wideband RCS Reduction of Dual-Band Fabry-Perot Cavity Antenna Using Pancharatnam-Berry Phase Coding Metasurface and AMC Surface

In this communication, we propose a dual-band Fabry-Perot (F-P) cavity antenna with a wideband low radar cross section (RCS) by integrating a Pancharatnam-Berry phase coding metasurface (PBPCM) and artificial magnetic conductor (AMC) surfaces. This antenna comprises two partially reflective surfaces (PRSs) that form two nested F-P cavities for signals in two bands. To reduce the monostatic RCS at high frequencies, a PBPCM is placed on the top side of the upper PRS, leveraging its ability to redirect reflected waves into different directions by encoding the phase on the metasurface. Additionally, two AMC surfaces etched on the top side of both the lower PRS and the ground plane further reduce the low-frequency RCS through phase cancellation. The overall antenna profile is also minimized, owing to the AMC’s flexible phase adjustment. The simulated and measured results verify the feasibility of the proposed method. The prototyped F-P cavity antenna exhibits a measured -10 dB impedance bandwidth of 4.15–4.8 and 7.8–8.4 GHz, with peak gains of 10 dBi at 4.45 GHz and 15.9 dBi at 8.3 GHz, respectively. Moreover, a wideband RCS-reduction bandwidth from 3 to 16 GHz is achieved under both x- and y-polarizations.