Due to the problems of low absorptivity and the narrow bandwidth of existing broadband absorbers, a perfect broadband tunable absorber with high absorptivity based on double-layer graphene is proposed in this study with 99% high absorptivity as the reference standard, and its theoretical analysis is performed. The designed absorber consists of complete graphene, upper dielectric material, patterned graphene, lower dielectric material and the gold substrate. Through numerical calculation, the designed absorbing structure can achieve high absorption rate of more than 99% in the range of 2.54–3.70 THz, and has a continuous bandwidth of 1.16 THz. In addition, the absorption range is 52%–100% by changing the Fermi level of the graphene layer. The perfect absorber is symmetrical in rotation center and insensitive to incident angle and polarization. It can be widely used in terahertz switch, modulator design, power acquisition and other related fields.

中文翻译：

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基于双层石墨烯的高吸收率宽带可调完美吸收体

针对现有宽带吸收体吸收率低、带宽窄的问题，本研究以99%的高吸收率为参考标准，提出了一种基于双层石墨烯的高吸收率完美宽带可调吸收体，其理论分析为执行。设计的吸收体由完整的石墨烯、上介电材料、图案化石墨烯、下介电材料和金基板组成。通过数值计算，设计的吸波结构在2.54~3.70 THz范围内可实现99%以上的高吸收率，并具有1.16 THz的连续带宽。此外，通过改变石墨烯层的费米能级，吸收范围为 52%–100%。理想的吸收体在旋转中心对称，对入射角和偏振不敏感。