Wideband Low RCS Antenna Based on Hybrid Absorptive-Diffusive Frequency Selective Reflector

A method for designing a wideband low radar cross section (RCS) antenna is proposed based on hybrid absorptive and diffusive frequency selective reflector (AD-FSR) in this paper. The low RCS antenna exhibits manifold frequency responses in three artificial bands, which are created by its different components. A simple U-slot patch antenna is borrowed, which is integrated with the diffusion metasurface, and placed under the absorptive sheet with about quarter wavelength. Then, the out-of-band incident wave is captured by the absorber in the lower frequency band, and diffused by the metasurface in the upper frequency band achieving the RCS reduction. The design strategies are explained and verified with the aid of the corresponding equivalent circuit model and current distributions. To illustrate the efficacy of the proposed approach, the low RCS antenna using the proposed hybrid AD-FSR structure is fabricated and tested, and the results demonstrate that the proposed structure is an attractive candidate for designing wideband low RCS antennas.