Ultra-Wideband Tunable Terahertz Metamaterials Absorber Based on Vanadium Dioxide

A terahertz ultra-wideband absorption tunable metamaterial was designed. The ultra-wideband absorber was designed using vanadium dioxide (VO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>), a phase change material, to dynamically adjust the absorption of the metamaterial by changing the conductivity of the VO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>. While the conductivity of VO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> increases from 200 S/m to 2×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup>S/m, the absorption rate can be adjusted between 3.1% and 100%.When the conductivity increases to 2×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup>S/m, the absorption bandwidth of the metamaterial reaches 5.12 THz, which has the effect of ultrawideband absorption, and the ultra-wideband absorption performance is significantly improved. Due to the quadruple rotational symmetry of the structural element, the absorption performance of the metamaterial is not sensitive to the polarization angle of the incident electromagnetic wave, and it has good incident angle stability.