Dual‐Band Low‐RCS Linear Polarized Array Based on II‐Shaped Polarization Conversion Metasurface

ABSTRACT This paper presents an II‐shaped polarization conversion metasurface (PCM) for radome applications, aiming to reduce the backward radar cross‐section (RCS) of antennas while enhancing their radiation performance. The proposed II‐shaped unit structure achieves a polarization conversion ratio (PCR) exceeding 90% across two independent frequency bands (5.4–7.92 GHz and 11.43–17.55 GHz), enabling effective manipulation of the polarization state of incident electromagnetic waves. The core innovation of the proposed design lies in its single‐layer structure enabling dual‐band polarization conversion, where the lower frequency band is primarily generated by the outer rectangular metal patch, while the higher frequency band is produced by the central I‐shaped metal strip, with independent tunability for each operating band. Furthermore, by arranging the PCM units in a checkerboard configuration, a 180° reflection phase difference between adjacent units is introduced, leading to significant suppression of co‐polarized backward scattering. Simulation results demonstrate considerable reduction in the monostatic RCS within the target frequency bands. This work provides a practical solution for the design of radomes that combine low observability with improved antenna performance.