The terahertz (THz) gap lying between the microwave and optical parts of the electromagnetic spectrum has attracted immense attention due to its applications between radiofrequency (RF)/microwave and photonic systems. A structure consisting of a graphene sheet sandwiched between two graphene disks is introduced herein to control the reflection, absorption, and transmission of THz waves. The proposed metamaterial structures are designed analytically using transmission line theory. Also, the dimensions of the structure and the electrical gating of the graphene are optimized utilizing a genetic algorithm. The structure is simulated using two different methods: (1) a circuit model based on transmission line theory and (2) commercial full-wave software based on the finite element method, which are verified by the agreement between their results. Finally, the proposed method is used to design a THz filter and THz wave absorber, which are in great demand for application in modulators, sensors, detectors, and imaging systems.

中文翻译：

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用于宽带应用中太赫兹波频率控制的石墨烯盘

由于其在射频（RF）/微波和光子系统之间的应用，位于微波和电磁频谱的光学部分之间的太赫兹（THz）间隙引起了极大的关注。本文介绍一种由夹在两个石墨烯盘之间的石墨烯片组成的结构，以控制太赫兹波的反射，吸收和透射。拟议的超材料结构是使用传输线理论进行分析设计的。同样，利用遗传算法优化了石墨烯的结构尺寸和电门控。使用两种不同的方法对结构进行仿真：（1）基于传输线理论的电路模型和（2）基于有限元方法的商用全波软件，这两种方法之间的一致性得到了验证。