Low-profile and wide-angle of a low RCS antenna based on a broadband polarization conversion metasurface

A broadband and high-efficiency polarization conversion metasurface (PCM) is used to reduce the radar cross section (RCS) and improve the radiation property of a patch antenna. The PCM is arranged in a checkerboard configuration comprised of square split-ring unit cells. The polarization conversion ratio (PCR) of the PCM unit is greater than 90% over a frequency range of 8.9 GHz to 21.8 GHz. The proposed patch antenna (PPA) has a low profile of 0.06 λL and is designed with the PCM loading on the surface of a patch antenna. The -10 dB RCS reduction bandwidth of the PPA is from 8.5 GHz to 22.0 GHz under normal incidence, and the low RCS property can be maintained as the oblique angles up to 60° for x- and y-polarized waves. Additionally, the PPA has a 10 dB return-loss bandwidth of 11.5-12.6 GHz and a peak gain of 8.02 dBi. The measured and numerical results confirm that the PPA exhibits wide-angle and broadband RCS reduction properties, while also improving the radiation properties at a low profile.