Gain enhancement and broadband RCS reduction of a circularly polarized aperture-coupled annular-slot antenna using metasurface

摘要

A circularly polarized microstrip slot antenna with low radar cross-section (RCS) and high gain was designed using a metasurface composed of a array of corner-truncated square patches placed on top of the upper substrate. By optimizing the geometry of the metasurface patches and L-shaped feed of the proposed antenna, broadband RCS reduction and improved overall antenna performance were achieved. A prototype antenna was fabricated, and the results showed that the proposed antenna exhibited an impedance bandwidth of 29.08 % in the frequency band of 4.29-5.75 GHz. The designed antenna achieved good 3-dB axial ratio (AR) bandwidth of about 30.18 % with center frequency of 5.3 GHz, and gain in the broadside direction of 9.9 dBi. Using the designed metasurface, remarkable monostatic RCS reduction was obtained in the frequency range from 4 to 13 GHz.