Effective material parameter retrieval for thin sheets: theory and application to graphene, thin silver films, and single-layer metamaterials

摘要

An important tool in the field of metamaterials is the extraction ofeffective material parameters from simulated or measured scattering parametersof a sample. Here we discuss a retrieval method for thin-film structures thatcan be approximated by a two-dimensional scattering sheet. We determine theeffective sheet conductivity from the scattering parameters and we point outthe importance of the magnetic sheet current to avoid an overdeterminedinversion problem. Subsequently, we present two applications of the sheetretrieval method. First, we determine the effective sheet conductivity of thinsilver films and we compare the resulting conductivities with the sheetconductivity of graphene. Second, we apply the method to a cut-wiremetamaterial with an electric dipole resonance. The method is valid forthin-film structures such as two-dimensional metamaterials andfrequency-selective surfaces and can be easily generalized for anisotropic orchiral media.