In-Band RCS Reduction of Waveguide Slot Array Using Metasurface Bars

A novel approach aimed at reducing the in-band radar cross section (RCS) of a waveguide slot array while maintaining its radiation performance is presented. Anisotropic metasurface is developed and applied to cover half of the antenna structure. The RCS reduction is based on the energy cancelation from the metasurface and the metal ground. Both simulated and measured results show that after loading the metasurface, the in-band RCS is sufficiently reduced for both copolarized and cross-polarized incident waves while the radiation performance is well retained. The proposed method is simple, low-cost, and easily fabricated, providing a new way for in-band RCS reduction of antenna array.