Low RCS Broadband High-gain Microstrip Antenna Based on a Double Arrow-type Polarization Conversion Metasurface

A polarization conversion metasurface (PCM) and a high-gain microstrip patch antenna for the Ka-band have been designed, with PCM units built into the antenna design in a checkerboard array pattern, lowering the antenna's radar cross section (RCS). The top-level design of the PCM unit features a truncated double-arrow pattern, with the outer arrow consisting of arc-shaped microstrip lines and the inner arrow consisting of right-angle microstrip lines. The antenna structure is relatively simple, comprising four radiating patches with gaps and a feed network composed of three U-shaped microstrip lines. Simulation results show that the polarization conversion ratio (PCR) of the PCM unit exceeds 80%, with a corresponding bandwidth of 19.65%(31.2GHz-38GHz), demonstrating excellent conversion performance. The overall dimensions of the antenna are 37 25 0.508 mm3, with an impedance bandwidth of 12.75% (32.15 GHz-36.53 GHz) for a reflection coefficient of less than −10 dB, and a maximum radiation gain is up to 13.4 dBi at 36 GHz. By combining the PCM with the antenna, RCS reduction has been successfully achieved.