Wideband low-RCS Fabry-Perot antenna with a low-profile enabled by an absorptive partially reflective surface

Partially reflective surface is essential especially in the Fabry-Perot (F-P) antenna to achieve high gain radiation property. However, it remains challenging to realize both high gain and wideband low-RCS at the same time. Here we propose a high-gain F-P antenna with a wideband radar cross section (RCS) reduction and a low-profile configuration based on a strategic absorptive partially reflective surface (APRS). Compared with the conventional meatasurface integrated in F-P antennas, the conflict between gain and RCS reduction is effectively resolved by the APRS with unidirectional absorption of the external waves instead of the radiated wave. Full-wave numerical simulations show that APRS achieves >0 dB monostatic RCS reduction within 6 ∼ 30 GHz and >10 dB monostatic RCS reduction in 10.5 ∼ 15.2 GHz, 22.5 ∼ 28 GHz, along with more than 10 dB bistatic RCS reduction within 6 ∼ 30 GHz even at incidence angles up to 45°. Meanwhile, the peak realized gain of 13.8 dBi is maintained due to the minimal absorption (approximately 3.7%) of the radiated wave from feed antenna. By properly tailoring the resonance conditions of the cavity, the total profile is minimized to 0.34 λc (λc is the free space wavelength at the center frequency). Finally, a prototype antenna is fabricated and the measured results validate that the proposed APRS broadens the application of multifunctional integrated stealth metasurfaces.