Bi-functional metasurface controlling electromagnetic wave scattering of differently polarized wave

We proposed an anisotropic metasurface performing different scattering properties depending on the polarization of the incident electromagnetic wave. The proposed metasurface is composed of orthogonally I-shaped structures with a thickness of only 0.067 working wavelength, and the reflection phase for certain linearly polarized incidence can be independently controlled by tuning the corresponding geometric parameters. Based on this principle we designed a bi-functional metasurface for differently polarized wave. It can behave as a phase-compensation planar reflector to transform the primary out-phase radiation from an x-polarized feeding antenna into a secondary planar wavefront with high directivity reaching 22 dBi. On the other hand, it behaves as a diffuse reflector composed of randomly distributed reflection phases to suppress the backward radar cross section in a broad band (8.2 GHz-12.5 GHz) under the illumination of y-polarized incident wave.

I. Introduction

Metasurfaces composed of subwavelength structures as the artificial inclusions have attracted much attention due to their great power to generate arbitrary wavefront by imparting the spatially varying phase discontinuities onto the incident electromagnetic (EM) wave [1]. Numerous interesting applications have been implemented based on this principle, such as propagating wave to surface wave conversion [2], photonic spin Hall effect [3], and ultrathin flat lenses [4]–[5], to name only a few.