Generalized equivalent circuit model for analysis of graphene/metal-based plasmonic metasurfaces using Floquet expansion

Abstract

Due to the wide range of applications of metal/graphene-based plasmonic metasurfaces (sensors, absorbers, polarizers), it has become essential to provide an analytical method for modeling these structures. An analytical solution simplified into a circuit model, in addition to greatly reducing the simulation time, can become an essential tool for designing and predicting the behaviors of these structures. This paper presents a high-precision equivalent circuit model to study these structures in one-dimensional and two-dimensional periodic arrays. In the developed model, metallic patches similar to graphene patches are modeled as surface conductivity and with the help of current modes induced on them, the equivalent impedance related to the array is calculated. However, the proposed method has less complexity than the previous methods, is more accurate and more flexible against geometry changes and can be applied to an array of patches embedded in a layered medium with minor changes and modifications. A Metal-Insulator-Metal metasurface, as well as an array of graphene ribbons placed on two dielectric layers, are investigated as two types of widely used metasurfaces in this paper and it is shown that the proposed circuit model is a fast and efficient method to predict the behaviors of these metasurfaces.