Wideband RCS Reduction for Circular-Polarized Slot Array Antennas Based on Composite Metasurface

This letter proposes a new method for reducing the RCS of circularly polarized antenna, utilizing a composite metasurface (CM) composed of frequency-selective rasorber (FSR) and polarimetric rotating-reflecting surface (PRRS) to reduce both out-of-band and in-band RCS of the antenna. The FSR consists of a lower-layer frequency selective surface (FSS) and an upper-layer lossy layer. The lossy layer is designed with periodic metallic patterns and integrated resistive loading, achieving high-efficiency wave absorption out of the antenna operating band while allowing wave transmission in the antenna's operating band. The PRRS is designed to effectively reduce in-band RCS by reshaping the scattering patterns within the operational frequency. This method addresses the issue of achieving both in-band and out-of-band RCS reduction for circularly polarized antennas, while also broadening the RCS reduction bandwidth. Experimental and simulation results show that the RCS reduction bandwidth ranges from 3.2 GHz to 19.6 GHz, with a relative bandwidth of 143.9%.