Transparent absorption-diffusion-integrated water-based all-dielectric metasurface for broadband backward scattering reduction

In this paper, we develop a transparent water-based all-dielectric metasurface (AMS) based on an absorption-diffusion-integrated design which can achieve microwave backward scattering reduction in a broad frequency band. As proof, two-type water-based resonators are introduced here arranged in a pseudorandom distribution above the indium tin oxide backplane. Owing to the frequency-dispersive permittivity, the water-based array can excite multiple electromagnetic resonances for highly effective absorption. Meanwhile, the pre-designed phase difference between two resonators also achieves diffusion-like scattering based on destructive interference, contributing further suppression of specular reflection. Calculation, simulation and experimental measurements demonstrate that our proposed absorption-diffusion-integrated water-based AMS can take advantage of electromagnetic absorption and destructive interference simultaneously for the broadband backward scattering reduction in the frequency band of 6.7-20.1 GHz. In addition, the proposed water-based AMS is also equipped with optical transparency performance, enabling a wide range of applications in the window glass of stealth armaments, electromagnetic compatibility facilities and photovoltaic solar devices.