Fine texture Lambertian electromagnetic metasurface generates background blending stealth effect in radar vision

The emergence of diffuse scattering metasurfaces offers the electromagnetic scattering stealth mechanism. However, the background blending stealth effect in radar vision induced by diffuse scattering metasurface has not been specially investigated. Here, a background blending Lambertian diffusive reflective metasurface for imaging radar stealth is designed by electromagnetic dispersion engineering. Compared to a conventional metasurface, the Lambertian metasurface achieves more uniform beam dispersion over a broad frequency range without significant main lobe formation at any frequency point, which provides ways for background fusion stealth. For conceptual validation, a metallic flat plate, coded metasurface, and Lambertian metasurface are fabricated and their radar images are obtained by two-dimensional imaging scanning measurement. As anticipated, the Lambertian metasurface notably alters the imaging edge characteristics in the radar images, effectively concealing the contours of the covered area. This work provides a wideband design method of the coded metasurface, which provides a new idea for designing stealth material and structures from the perspective of radar imaging and is immensely helpful for practical application in jamming recognition stealth of coding metasurfaces.