Ultrawide-angle generalized Brewster metasurface

Abstract

A generalized Brewster impedance matching theory is proposed in this paper to overcome the performance degradation of conventional metasurfaces at large incidence angles and achieve ultrawide angular stability. To begin, in the case of transmission, the characteristic impedance of anisotropy metasurface, denoted by incidence angle and constitutive parameter tensor, is obtained by extending the constitutive parameter from the isotropy scalar to the anisotropy tensor. The theoretical formulas used to derive the generalized Brewster impedance matching condition extend the classical Brewster phenomenon to the entire angular domain. The constitutive parameters of the anisotropy metasurface are then extended to the complex domain for the case of absorption, and the complex reflection coefficient of the absorptive metasurface is established in the angular domain. To realize ultrawide-angle absorption, the generalized Brewster complex-impedance matching condition is derived, allowing the extension of ultrawide-angle transmission to absorption. Finally, ultrawide-angle transmissive and absorptive metasurfaces are designed, and their transmission of 0${~}^{\circ}$–80${~}^{\circ}$ and absorption performance of 0${~}^{\circ}$–75${~}^{\circ}$ are demonstrated using simulations and measurements.