Low-scattering metasurface array antenna based on characteristic mode theory

A rapid design method for a metasurface array antenna with a low radar cross section (RCS) based on characteristic mode theory is proposed. An anisotropic metasurface element providing a reflection phase difference of 180° ± 37° under x- and y-polarized normal incidence was first designed. The element and its 90°-rotated counterpart were then arranged in a checkerboard configuration to form a low-RCS metasurface. Characteristic mode analysis was performed to select the desired operating modes and determine the feeding structure and feeding position, yielding two antenna elements with similar operating bands. Finally, the metasurface was converted into a low-RCS array antenna. Simulated and measured results demonstrated good radiation performance and dual-polarized in-band and out-of-band RCS reduction.