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体

在本文中，我们提出了在双太赫兹频带上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。说明了所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限。使用反演算法提取等效阻抗并探索多峰吸收的物理机制。当费米能级发生变化时，通过算法探索等效阻抗，从而确定相应吸收峰的谐振频率变化。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，我们将提出的结构改编成反向设计的模式，从而实现了双频带吸收峰和可调性的相似特性。因此，我们的工作为各种可调多频带太赫兹超材料完美吸收体提供了新的见识和有用的设计指导。