Wideband low-RCS metasurface antenna based on reflection cancellation and characteristic mode analysis

Abstract A metasurface (MTS) antenna with wideband radiation and low radar cross section (RCS) performance is proposed. The design is based on a two-step RCS reduction (RCSR) strategy applied to a reference antenna – a conventional 4 × 4 square patch array MTS antenna that exhibits stable broadside radiation within 5–6.5 GHz. In the first step, the patch array of the reference antenna is reconfigured into a quasi-chessboard MTS using the principle of reflection cancellation, enabling wideband RCSR under both x - and y -polarized incidences. In the second step, guided by the antenna scattering theory based on characteristic modes, six slots are etched on the ground plane to further enhance RCSR under x -polarized incidence. Characteristic mode analysis is employed throughout the design process to simultaneously analyze radiation and scattering behaviors. Compared with the reference antenna, the proposed MTS antenna maintains similar radiation performance while achieving monostatic RCSR bandwidths of 3.7–11.3 and 4.7–11.3 GHz for x - and y -polarized incident waves, respectively. It also demonstrates significantly broader RCSR bandwidths compared to a metallic plate of the same size.