Analysis of Two-Layer Metasuface using Generalized Sheet Transition Conditions and Babinet’s Principle

A method to analyze the surface admittance of two-layer metasurface is presented. The two-layer metasurface is modeled by the surface admittance of each layer and transmission line of an air-gap. Generalized sheet transition conditions (GSTCs) and Babinet’s principle are used to calculate the surface admittance. The reflection coefficients of the two-layer metasurface were calculated at normal and oblique incidence. The results show that our method well agrees with full-wave simulation, indicating its validity. This method includes angle dependency of the metasurface due to the surface susceptibilities of the normal component.