Design and analysis of graphene-based THz absorber using multi-layer structure based on increasing profile for conductivity of the graphene layers

In this work, the equivalent circuit model is used to explain the design process of a graphene absorber, which aims to achieve high absorption through the impedance matching of the structure with free space impedance. In the proposed structure, the dielectric layers and periodic graphene ribbons are used that are placed on a good conducive surface. The proposed model has a multi-layered structure and the graphene conductivity rises from bottom to top. In this work, the equivalent circuit model is presented and the design process is described, then several structures with different layers (at different frequencies) are studied, designed and simulated. Based on the proposed structure, can be achieved to a high 90% absorption at the central frequency.