A broadband metamaterial absorber based on multilayer-stacked structure

Abstract

In this paper, a broadband metamaterial absorber (MA) based on multilayer structure is proposed in the terahertz region. Different from the general multilayer structure, the structure we designed superimposes with different resonators in the “horizontal direction” of the bottom metal plate. The unit of the absorber is composed of several different size metal and dielectric layers which are placed vertically on a metal plate. The numerical results show that the MA has a broadband absorption from 5 THz to 7.75 THz, with the absorption rate larger than 80%. A calculation formula is first given to calculate the absorption frequency, and we compare the simulation results with the calculation results to verify the accuracy of the formula. What is more, the physical mechanism of the perfect absorption can be studied based on the distribution of E-field in the absorber, the standing wave theory, the distribution of energy density and the equivalent impedance theory.