为了在THz波段获得TE波下的可调谐吸收频谱, 采用全波仿真的方法, 设计了一款基于二氧化钒材料的可调谐THz吸波器, 对该吸波器的吸收频谱、电场图、表面电流图以及能量损耗图进行分析, 并讨论了结构参量h4,k以及入射角度θ对吸收频域和吸收带宽的影响。结果表明, 通过外部温控的方式改变二氧化钒谐振单元的物理特性可以获得可调谐的吸收频谱并改善吸波器的吸收性能, 该吸波器在温度T≥68℃时, 可以实现在2.70THz~3.36THz频段的宽带吸收(吸收率在90%以上), 相对带宽达到21.8%;在T＜68℃时, 可以实现多个单频点的吸收;改变结构参量h4,k可以改变吸收频点的位置以及吸收带宽, 改变入射角度θ可以影响吸波器的吸收效果。该研究对可调谐太赫兹器件的进一步探究是有帮助的。

In order to obtain the tunable absorption spectrum of TE wave in THz band, a tunable THz absorber based on vanadium dioxide was designed by full-wave simulation. Absorption spectrum, electric field, surface current and energy loss of the absorber were analyzed. The effects of structural parameters h4, k and incident angle θ on absorption frequency domain and absorption bandwidth were discussed. The simulation results show that, tunable absorption spectrum can be obtained and absorption performance of the microwave absorber can be improved by changing the physical characteristics of vanadium dioxide resonator unit through external temperature control. When T≥68℃, broadband absorption of microwave absorber can be achieved in 2.70THz~3.36THz band. Absorption rate is above 90% and relative bandwidth can reach 21.8%. When T＜68℃, multiple single frequency points can be absorbed. The position of absorption frequency point and absorption bandwidth can be changed by changing the structural parameters h4 and k. The absorption effect can be affected by changing incident angle θ. This study is helpful for further research of tunable terahertz devices.