Tunable Graphene-Based Wave Absorber: Combined Electrical and Mechanical Tuning

Abstract

Here in this work, a graphene-based absorber in THz waves is introduced. The structure exploits the mechanical adjusting setup using a Micro-Electro-Mechanical Systems comb driver. In addition, the periodic graphene rings and disks are used on top of the TOPAS (cyclic olefin copolymer) spacer. The middle layer spacer is considered as an air gap that can be filled by any target samples. The mechanical tuning besides the influence of the chemical potential makes the proposed structure most tunable with more than five absorption peaks in the THz gap. Two parallel simulation paths are followed in this work. First, an equivalent circuit model representation is developed, and the absorption response is obtained by leveraging the impedance matching theorem. Then the full-wave numerical modeling via the finite element method is performed to investigate the first approach’s validity and accuracy. It is shown that combining electrical and mechanical stimulations can change the number of absorption peaks and also their frequencies. According to the simulation results, the proposed absorber is highly reliable and robust against probable geometrical mismatches, while almost all of the THz spectrum is covered by the proposed structure.

Keywords

graphene / graphene-based terahertz / absorber / circuit model / sensor

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