Realization of multifunctional transformation based on the vanadium dioxide-assisted metamaterial structure

In this paper, a multifunctional device and a design method are proposed based on the vanadium dioxide (VO₂)-assisted metamaterial structure. The structure comprises several layers arranged from top to bottom, including a VO₂ patch layer, a polyimide (PI) dielectric layer, an elliptical metal layer, a VO₂ thin film layer, another PI dielectric layer, and a bottom metal layer. The research results show that the metamaterial structure enables linear-to-linear (LTL) polarization conversion and linear-to-circular (LTC) polarization conversion across multiple frequency bands when the VO₂ is in the insulating state. Moreover, as the VO₂ material undergoes a transition from the insulating state to the metallic state, the multifunctional structure can function as a broadband absorber, exhibiting an absorption rate of over 90% within the frequency range of 1.751-3.853 THz, with a relative bandwidth of 75%. This versatile conversion device holds great potential for applications in terahertz system and smart system fields.