Tunable Three-Band Vanadium Dioxide Metamaterial Absorber for Terahertz Nondestructive Testing

Terahertz metamaterial absorbers can effectively modulate terahertz waves by design due to the ability to design the shape, structure and size of metamaterial cells. Therefore, they have great potential in terahertz nondestructive testing and are widely used in insulation equipment detection, aerospace, biomedical fields. To address the current problems of single absorption band and non-tunable, a new three-band tunable metamaterial absorber/reflector is designed in this paper. The device consists of elliptical vanadium dioxide and a metal base plane separated by a silica dielectric layer. Numerical simulation results show that when VO2 is in the insulated state, it is almost in the fully reflective state. When the vanadium dioxide is in the metallic state, there are three perfect absorption peaks in the range of 2.5 to 5 THz. The equivalent impedance and surface current distribution of the absorber are further analyzed and discussed, and the mechanism of vanadium dioxide regulation of the absorption performance is elaborated. In addition, the effect of structural parameters on the absorption effect is discussed in this paper, which provides guidance for the optimization of the structure.