Input impedance angle-stability modulation design of dielectric-enhanced high-density stacking RFSS absorbers for monostatic RCS reduction

Dual-polarization, wide-band, and wide-angle monostatic radar cross section (RCS) reduction of a metal plate is reported. Through analysis of specular and non-specular scattering mechanisms based on surface impedance boundary condition, revealing that the absorber’s input impedance requires angular-stability but need not match the free-space wave impedance at oblique incidence. Dielectric-enhanced high-density stacking resistive frequency selective surface (RFSS) absorber with both specular and non-specular scattering suppression is constructed. Simulation results show that the proposed absorber has better than 10 dB absorption in the 1.5–18 GHz range at normal incidence. As for oblique incidence, approximate 10 dB RCS reduction is realized within 0-90° at 2 GHz and 8 GHz under TE polarization, while for TM polarization, RCS reduction is significant within 0-85° at 2 GHz, especially in the angular range where the surface wave is excited, more than 20 dB RCS reduction is achieved. Samples have been fabricated and measured in the anechoic chamber. Measurement results show good consistency with simulation results, validating the effectiveness of analytic methods and design principles.