Multi-band terahertz anisotropic metamaterial absorber composed of graphene-based split square ring resonator array featuring two gaps and a connecting bar
Somayyeh Asgari, Tapio Fabritius
Abstract
A multi-band anisotropic metamaterial absorber operating in the terahertz (THz) range is constructed using a graphene-based split square ring resonator array featuring two gaps and a connecting bar. The design is meticulously simulated through the finite element method (FEM) using CST Software. Subsequently, an equivalent circuit model (ECM) is introduced, leveraging impedance and transmission lines, and implemented with a rapid MATLAB code to evaluate the absorber's behavior in the THz spectrum. The proposed absorber, dynamically adjustable through a one-layered resonator array, exhibits a strong linear dichroism response of 99% within a frequency range of 0.3-4 THz. The metamaterial has an absorption rate of 81% for one absorption band in transverse magnetic mode and its three absorption bands in transverse electric mode have an average of 99.3% in each absorption band with absorption over 99%. This absorber holds potential applications in polarization-sensitive devices and THz systems. The ECM model was established to provide an efficient analytical tool for assessing the absorber's performance, and the FEM simulation results align well with those derived from the ECM.