Phase Random Metasurface With Diffuse Scattering Based on Subwavelength Unit's Design of Shunt Resonance Circuit

It is known that metasurface composed of randomly distributed subwavelength unit cells with different reflection phases features some specific electromagnetic behaviors, of which diffuse scattering property can be applied to reduce Radar Cross Section (RCS). In this paper, a subwavelength unit cell based on shunt resonance is designed. Since shunt resonance can provide stable phase distribution within the range between its double resonant frequency points, reflection phase variation of the subwavelength unit cell can be slight. Equivalent transmission line model presented proves effective on extracting reflection phase of a sub-wavelength unit cell. Referring to variation of its normalized reactance versus frequency, we adjusted microstructure layout of the sub-wavelength unit cell until its reflection phase variation become gentle over X and Ku band. Six different scaling unit cells are chosen to form diffuse scattering metasurface. Simulation and experimental results exhibit that monostatic RCS reduction more than 10 dB can be realized over X and Ku band.