Broadband Reduction of Monostatic and Bistatic RCS Using Blocks of 2-bit Anisotropic Meta-Coatings

The nonabsorbing encoded checkerboard-like meta-coatings (MCs) for RCS reduction are proposed to be used in the form of sets of several flat blocks with the same final dimensions. The reduction of monostatic and bistatic RCS for co- and cross-polarizations for two developed flat blocks of digital anisotropic MC is investigated. The cells of the metasurface contain two coupled elliptical ring resonators and are distinguished by 2-bit coding of the tilt angle of the anisotropy axis. The RCS reduction of two blocks under normal irradiation is approximately the same and not less than 12 dB in the band 9.8 to 21 GHz. A good matching between the simulation and measurement results of the backward scattering patterns (BSP) of blocks in the region of the central lobes for various planes and polarizations of the irradiation is obtained. In the principal planes, the blocks cancel the central lobes of the BSP by 10-25 dB; in the sector of angles of around ±40°, the backward RCS of the blocks is lower than that of the reference. In the diagonal planes, there is a cancellation by 13-15 dB and an expansion of the central lobe of the BSP for co-polarizations, as well as a bifurcation of this lobe for cross-polarizations in the sector of angles ±9°; outside of this sector the RCSs of the blocks are commensurate with the RCS of the reference.