Low RCS and high‐gain CP microstrip antenna using SA‐MS

A shared aperture metasurface (SA‐MS) is proposed to achieve the wideband radar cross‐section (RCS) reduction and gain enhancement of a circularly polarised (CP) microstrip antenna simultaneously. The SA‐MS is composed of a wideband polarisation conversion surface and a partially reflecting surface (PRS). A 180° phase difference can be obtained by the polarisation conversion surface, which results in a wideband RCS reduction in normal incident direction. The Fabry–Perot resonator cavity is constructed by the PRS and the metallic ground of the CP microstrip antenna to enhance the gain. Experimental results show that the gain enhancement reaches 1.15 dB around the operating band and a wideband RCS reduction is obtained in the frequency range of 9–17 GHz, in which the average RCS reduction is 10.9 and 10.68 dB for dual polarisation in the normal incident direction.