Broadband Polarization Conversion Metasurface for Antenna RCS Reduction

A broadband polarization conversion metasurface (PCM) is proposed for reducing radar cross section (RCS) of antenna. The unit cell of the PCM consists of two pairs of tapered L-shaped strips, a layer of air, and a ground plane. The PCM unit achieves polarization rotation (PR) bandwidth of 117.2% with the polarization conversion ratio (PCR) of 90%. The broadband characteristics of the PCM are studied by an equivalent circuit. The chessboard PCM reduces RCS under a linear polarized (LP) incident wave. The PCM is integrated into a dual-polarized 2 $\times $ 2 H-shaped slot array antenna for RCS reduction. The measured results show that the monostatic RCS of the antenna is reduced by about 10 dB in the frequency range of 9.6-33.1 GHz and 9.8-33.2 GHz for $x$ - and $y$ -polarization under normal incidence, respectively, while the radiation performance of the antenna remains unchanged.