Coding diffusion metasurface for ultra-wideband RCS reduction

A coding diffusion metasurface is designed and fabricated for ultra-wideband radar cross-section (RCS) reduction. Two kinds of unit cells based on square ring patch are employed to generate the ‘0’ and ‘1’ elements of the coding metasurface. By precise design of the unit cells, a 180° ± 37° reflection phase difference between these cells is achieved over 8.01–22.76 GHz, leading to dramatically reduce the scattering field level by more than 10 dB. To obtain the diffusion far-field pattern of the metasurface, the optimisation algorithm is utilised to calculate the optimal layout of the digital elements. Both full-wave simulation and measurement results verify the capability of the proposed metasurface.