Phase Transition Material Based Wideband, Tunable, and Fabrication Friendly Metamaterial Absorber

This work studies three simpler models of meta-material absorber (MA) and proposes an optimum structure for achieving broad bandwidth and high tuneability within the terahertz frequency range, utilizing vanadium dioxide (V O
2
) as the phase transition material. The optimization, simulation, and analysis of the best among the three models were performed using CST Studio Suite with the Finite Integration Technique. Subsequently, the main absorption spectrum was verified using the finite element method-based COMSOL Multiphysics software. The simulation result demonstrates that the MA achieves absorption above 90% within the range of frequencies from 2.94 THz to 6.12 THz, providing an operating bandwidth of 3.18 THz. Importantly, the absorptivity of this suggested structure may be continuously tuned from 2.3% to 100% by adjusting the conductance of V O
2
, enabling the transition of V O
2
from an insulating stage to a metallic stage. Additionally, the best model exhibits insensitivity to polarization and has significant absorption for incident angles up to 60°. The recommended structure is validated using the impedance matching theorem and interference cancellation condition. The physical mechanics of the MA is elaborated by analyzing the electromagnetic field distribution around the resonance frequency. Potential applications of this absorber include sensors, modulation, imaging, terahertz filters, optical switching, and more.