An integrated 2-bit metasurface array antenna with broadband low radar cross-section covering large incident angle space

Based on an integrated design of metasurface units and antenna elements, a 2-bit metasurface array antenna with broadband low radar cross-section (RCS) covering large incident angle space is proposed in this study. The slot width's influences on the reflective phase and element radiation performance are analysed. Furthermore, a genetic algorithm is utilised to obtain the coding pattern of the array antenna with diffuse scattering characteristics. A wideband RCS reduction is achieved from 4.2 to 9.0 GHz under x-polarised incidence, and it has oblique incident angle stability ranging from 0 degrees to 60 degrees due to non-uniform element arrangement. The current cancelation phenomenon is found to reveal the RCS reduction mechanism. Besides, the proposed antenna gain is 15.9 dBi with a peak aperture efficiency of up to 90.8%. Experimental results have a close coincidence with the simulations, which verifies the capability of the proposed design.