An optically transparent unequal proportional coding metasurface with absorption and diffusion integrated mechanism for ultra-broadband RCS reduction

In this paper, a novel uneven layered transparent absorption-diffusion integrated coding metamaterials is proposed to suppress the ultra-broadband backward scattering within a wide angular domain. The metasurface achieves RCS reduction through the combined action of scattering and absorption mechanisms. The two different units of this metasurface exhibit a reflection phase difference of 180 ± 37° covering from 3.1 to 17.1 GHz with various amplitudes for both the morphology of the units and the location on the different planes. Additionally, an unequal proportional design of the coding metasurface is applied to further enhance the diffusion of the backward scattering wave at a specific frequency. Then, the arbitrary coding sequence of the units is optimized using the particle swarm optimization (PSO) algorithm to obtain the optimal arrangement of the units. This novel coding metasurface can achieve a wide-angle low-scattering characteristic from 0° to 50° for transverse electric (TE) and transverse magnetic (TM) polarizations, demonstrating a considerable potential for future microwave absorbing and shielding glasses applications.