A tunable ultra-wideband metamaterial absorber based on graphene is presented herein. Its absorption exceeds 90% from 1.57 to 8.46 GHz when the Fermi level of the graphene is 0.7 eV, and it can be tuned by changing the bias voltage applied on the graphene. To explore the mechanism of its wideband absorption and tunability, the surface current of the metamaterial absorber at given absorption frequency is monitored for different Fermi levels. Further simulation results indicate that the absorption by the metamaterial absorber is insensitive to the polarization state of the incident wave but sensitive to its angle of incidence. The absorber offers the advantages of simplicity, ultra-wideband operation, and tunable absorption, having potential applications in the fields of electromagnetic stealth technology, detectors, and communication.

本文提出了一种基于石墨烯的可调谐超宽带超材料吸收器。当石墨烯的费米能级为0.7 eV时，其吸收率从1.57 GHz到8.46 GHz超过90％，并且可以通过改变施加在石墨烯上的偏置电压对其进行调谐。为了探索其宽带吸收和可调性的机理，在给定的吸收频率下，针对不同费米能级监测超材料吸收器的表面电流。进一步的仿真结果表明，超材料吸收器的吸收对入射波的偏振态不敏感，但对入射角敏感。该吸收器具有简单，超宽带操作和可调吸收的优点，在电磁隐身技术，探测器和通信领域具有潜在的应用。