Circularly Polarized Antenna with Ultrawideband RCS Reduction Based on Polarization Conversion Metasurface

In this paper, a circularly polarized antenna with ultrawideband out-of-band radar cross section (RCS) reduction based on polarization conversion metasurface (PCM) is created. A polarization conversion unit consists of 3 pairs of symmetrical L-shaped strips. The substrate and air gap are designed to expand the working band of the PCM to achieve ultrawideband RCS reduction. Polarization conversion bandwidth of the designed PCM unit is 6.9-25.2 GHz (114%) with a polarization conversion ratio exceeding 90%. The circularly polarized antenna loaded with PCMs has a radiated operating frequency of 6 GHz and an ultrawideband RCS reduction from 8.8 to 27 GHz (101.7%).