Dual‐Layer Polarization Conversion Metasurface Wideband Low‐RCS Circularly Polarized Antenna

ABSTRACT A double‐layer polarization conversion metasurface arranged in a chessboard configuration is proposed to realize a low‐observable circularly polarized (CP) antenna with significant radar cross section (RCS) reduction. The double‐layer metasurface (MS) unit is jointly composed of a polarization‐rotating surface (PRS) and a phase control surface (PCS). The upper PCS modulates co‐ and cross‐polarized reflected wave phases to broaden the lower‐layer PCR bandwidth, it provides electromagnetic isolation and enhances the radiation performance of the antenna. Furthermore, by designing slots of different shapes on the ground plane, the axial ratio bandwidth and RCS reduction bandwidth are further increased. Simulation results show that the antenna achieves an RCS reduction bandwidth exceeding 5 dB across the 6.5–19.6 GHz range (101%), and an RCS reduction bandwidth of more than 9 dB reaching 95.7% (6.8–19.3 GHz), covering both X and Ku radar frequency bands. In addition, the antenna has an impedance bandwidth of 9.4–12.1 GHz (25.1%), a 3 dB axial ratio (AR) bandwidth of 10.3–12.1 GHz (16.1%), and a peak gain of 8.9 dBic. The measured results are basically consistent with the simulated results, further verifying the antenna design.