A tunable broadband metamaterial absorber is proposed based on the vanadium dioxide and Fabry-Perot cavity in the terahertz region. To broaden the absorption bandwidth, the dielectric coating is employed on the top of vanadium dioxide squares to form the Fabry-Perot cavity for improving the impedance matching and further triggering an additional resonance frequency. The simulation results indicate that the bandwidth of absorption over 90% reaches 3.43 THz with a central frequency of 2.645 THz and the corresponding relative bandwidth is 129.7% under normal incidence. The absorption peak can be approximately tuned from 8% to 100% by changing the conductivity of vanadium dioxide. Moreover, it is polarization-insensitive, and exhibits absorption performance of working at wide-angle incidence. This design method can serve as a reference to research tunable and broadband terahertz devices.

提出了一种基于太赫兹地区二氧化钒和法布里-珀罗腔的可调谐宽带超材料吸收器。为了加宽吸收带宽，在二氧化钒方片的顶部采用介电涂层以形成Fabry-Perot腔，以改善阻抗匹配并进一步触发附加的谐振频率。仿真结果表明，法线入射时，90％以上的吸收带宽达到3.43 THz，中心频率为2.645 THz，相应的相对带宽为129.7％。通过改变二氧化钒的电导率，吸收峰可以从8％大约调整到100％。此外，它对偏振不敏感，并且表现出在广角入射下工作的吸收性能。