Omnidirectional Absorber for Dual Polarizations Based on Generalized Brewster Effect in Highly Dissipative Metasurface

Brewster effect originally refers to the reflectionless transmission of a TM-polarized wave impinging on a lossless dielectric surface at a particular angle. It is generally thought that either the introduction of loss or the change of polarization will break the reflectionless phenomenon. Here, we derive an analytical solution for achieving the generalized Brewster effect in highly dissipative anisotropic media for both TE- and TM-polarized waves. Based on the composite electric and magnetic resonator, we designed a 3-D metasurface with controllable Brewster angles to absorb dual-polarized incident waves without reflection. By stacking massive different metasurface units, each with a deliberately designed Brewster angle, it is possible to achieve omnidirectionally matched absorption for dual-polarized incident waves from a given source. As a proof of concept, we implemented an inhomogeneous planar metasurface. Each unit of this metasurface has a Brewster angle precisely adjusted according to a given line source, which is used to absorb the corresponding impinging wave without reflection. Both full-wave simulations and experimental measurements confirm the nearly omnidirectionally matched absorption. Our work offers a promising approach for applications of metasurfaces in electromagnetic shielding, compatibility, and microwave measurements.