In this paper, we proposed a tunable graphene-based metamaterial absorber (MA) at dual terahertz band to achieve perfect absorption. The electric field intensity distributions of demonstrated structure is illustrated to explain the origin of two absorption peaks. Simulation result shows the proposed MA owning polarization-insensitive property and wide incident angle tolerance. An inversion algorithm is used to extract the equivalent impedance and explore the physical mechanism of multiple-peak absorption. The equivalent impedance is explored through algorithm when the Fermi energy level alters, consequently the variation of resonant frequency of corresponding absorption peak is determined. Simultaneously, the resonant frequencies of absorption peaks can be adjusted by changing the geometric parameters of the graphene. Furthermore, we adapt the proposed structure into reversely designed pattern, achieving similar characteristic of dual-band absorption peaks and tunability. Thus, our work provides new insight and useful design guidance to various tunable multiple band terahertz metamaterial perfect-absorbers.

中文翻译：

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基于反向石墨烯贴片超材料的双峰可调太赫兹完美吸收器


在本文中，我们提出了一种在双太赫兹波段可调谐的基于石墨烯的超材料吸收器（MA），以实现完美的吸收。图示了所展示结构的电场强度分布，以解释两个吸收峰的起源。仿真结果表明，所提出的MA具有偏振不敏感特性和宽入射角容差。采用反演算法提取等效阻抗并探索多峰吸收的物理机制。通过算法探索费米能级变化时的等效阻抗，从而确定相应吸收峰谐振频率的变化。同时，可以通过改变石墨烯的几何参数来调节吸收峰的共振频率。此外，我们将所提出的结构采用逆向设计模式，实现了相似的双带吸收峰特性和可调谐性。因此，我们的工作为各种可调谐多频段太赫兹超材料完美吸收器提供了新的见解和有用的设计指导。