The concept of a wideband and polarization-insensitive absorber based on graphene for terahertz (THz) applications is presented in this paper. To broaden the absorption bandwidth, we have combined two concentric rectangular rings with cross-shaped strips. These are located on a silicon substrate. The analysis of the proposed absorber is based on the impedance matching theory and finite difference time domain (FDTD) methods. The simulated results show that the proposed absorber has a wideband absorption. The obtained bandwidth for absorption coefficients of 0.9 and 0.7 are 16% and 20.3%, respectively over the range of 2.47–2.9 THz and 2.39–2.93 THz. The bandwidth and absorption performance of the absorber can be adjusted by the control of the conductivity of graphene by applying an external DC-bias voltage. Due to the symmetrical design of the structure, the presented absorber is polarization insensitive. Furthermore, due to having a cross-strip structure, the performance of the proposed absorber is insensitive to the angle of the radiant wave. Thus, the proposed absorber can be considered a suitable candidate for various THz applications.

本文提出了一种基于石墨烯的宽带不极化吸收体的概念，用于太赫兹（THz）应用。为了扩大吸收带宽，我们将两个同心的矩形环与十字形条结合在一起。这些位于硅衬底上。所提出的吸收器的分析基于阻抗匹配理论和时域有限差分（FDTD）方法。仿真结果表明，所提出的吸收器具有宽带吸收性能。在2.47–2.9 THz和2.39–2.93 THz的范围内，所获得的0.9和0.7的吸收系数带宽分别为16％和20.3％。吸收剂的带宽和吸收性能可以通过施加外部直流偏置电压来控制石墨烯的电导率来进行调节。由于结构的对称设计，因此提出的吸收器对偏振不敏感。此外，由于具有交叉带结构，因此提出的吸收器的性能对辐射波的角度不敏感。因此，提出的吸收器可以被认为是各种THz应用的合适候选者。