Anisotropic 3-bit Metasurfaces with Combined Modules with Rotation Symmetry for Wideband RCS Reduction

摘要

Coded metasurfaces (MSs) with diffuse scattering are investigated. To this end, two rotationally symmetric MS modules are proposed. The anisotropy axes of metaparticles (in the dumbbell-shape) are rotated in polar coordinate systems specified at the centers of the modules. On the basis of various combinations of whole modules and their fragments (of the “kaleidoscope” type), four combined MSs with reduced RCS in a wide frequency range are offered. The simulation showed the RCS reduction of the MSs for linear-polarized normal incidence waves for co-polarizations of at least 8-9 dB in the band 8.4 to 19 GHz. In the case of circular polarizations of irradiation, the scattered field represents diffractive vortex beams with zero intensity in the opposite direction (for co-polarizations) and orbital angular momentum of the first order. The diffractive lobes are deviated 15° to 45° from the backward direction at different frequencies. The backscattered field of circular cross-polarizations is canceled by at least 9 dB in the band from 8.3 to 19 GHz (relative to the cross-polarized field of reference).