A High-Gain Circularly Polarized Fabry–Perot Antenna With Wideband Low-RCS Property

In this letter, a low radar cross section (RCS) and the high-gain circularly polarized (CP) antenna using a novel linear-to-circular polarization converter is presented. A simple linearly polarized patch antenna rotated 45° relative to x-axis is used as the primary source. The polarization converter is an asymmetrical metastructure composed of different metal patterns printed on the two sides of a dielectric substrate, which can transmit a CP wave. The top-side metallic pattern is an absorbing surface to realize the RCS reduction, while the bottom-side one is a partially reflective surface (PRS). A CP Fabry-Perot resonance cavity is constituted by the PRS and the anisotropic high-impedance surface (HIS) plane to obtain the gain enhancement. The simulation and measured results demonstrate that the proposed antenna exhibits good circular polarization performance in the operating frequency. In addition, the gain of the proposed antenna can be improved by about 3.2 dB at 10.7 GHz, and the RCS can be reduced significantly over a wideband ranging from 4 to 13 GHz for both polarizations, compared with the conventional patch antenna.