A tunable graphene terahertz metamaterial absorber is designed by treating a monolayer continuous dumbbell-shaped structure graphene layer, which can simultaneously realize the narrow bandwidth and dual-band absorption with transverse magnetic (TM) polarization and wide incident angle operation. Two pronounced absorption peaks are caused by the novel toroidal dipole phenomenon and magnetic plasmon polariton. By optimizing the geometry parameters, the relative narrow bandwidths of the two absorption peaks are 26.4 and 23.5 GHz at frequencies of 0.2242 THz and 0.5302 THz, respectively, with the absorption rate above 99.6%. Since the continuous dumbbell-shaped graphene structure is treated in the absorber, a more convenient way to realize the tuning ability by treating a bias voltage compared to the absorbers with discrete graphene structures. The designed device can work at a wide incident angles (up to 80°) under TM polarization with the absorption above 88% at low frequency. The simulation results are basically in good agreement with the results of the equivalent circuit model. This work offers huge potential applications in terahertz imaging, detecting and sensing, especially in the 6G communication systems.

通过处理单层连续哑铃形结构石墨烯层，设计了可调谐石墨烯太赫兹超材料吸收体，该层可同时实现窄带宽和双带吸收以及横向磁极化和宽入射角操作。新型环形偶极子现象和磁等离子体激元极化导致两个明显的吸收峰。通过优化几何参数，在0.2242 THz和0.5302 THz的频率下，两个吸收峰的相对较窄带宽分别为26.4和23.5 GHz，吸收率高于99.6％。由于在吸收体中处理了哑铃形的连续石墨烯结构，因此与具有离散石墨烯结构的吸收体相比，通过处理偏置电压更容易实现调谐能力。所设计的器件可以在TM偏振下以宽入射角（高达80°）工作，并且在低频下的吸收率超过88％。仿真结果与等效电路模型的结果基本吻合。这项工作在太赫兹成像，检测和感测中提供了巨大的潜在应用，尤其是在6G通信系统中。