Bifunctional Metasurface for Linear Polarization Conversion and Absorption using Vanadium Dioxide

Vanadium dioxide $\left(\mathbf{V O}_{2}\right)$ is a phase change material that exhibits reversible insulator-to-metal transition close to 68 °C. During the phase transition, VO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> shows more than three orders of resistance switching, changing its behavior to metallic at high temperature, which makes it suitable for RF switching and tunable microwave devices. Traditional metasurfaces are typically designed for a single application with fixed frequency response. This simulation work reports a VO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> based switchable bifunctional metasurface which can achieve polarization conversion and electromagnetic absorption through phase transition of VO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>. In the insulating state of VO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>, the proposed metasurface acts as a linear polarization converter from 17.9 GHz to 22.9 GHz with more than 90% polarization conversion ratio. Whereas, in the metallic state of VO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>, the designed metasurface acts as an absorber from 15.86 GHz and 23.02 GHz with less than -10 dB reflection. The presented approach to obtain dual functionality may stimulate new ideas to design multifunctional microwave devices.