Design and Analysis of Dual-band Hexagon-shaped Polarization-insensitive Metamaterial Absorber using Vanadium dioxide (VO2) for Terahertz Applications

This research aims to present a comprehensive design and analysis of THz metamaterial absorbers based on vanadium dioxide (VO2). This article covers all aspects of design verification, including mathematical analysis, parametric studies, materials investigations, and modeling using an equivalent circuit approach. The proposed metamaterial absorber (MMA) designs comprise three layers: vanadium dioxide (VO2) as a radiating element, silicon dioxide (SiO2) as a dielectric substrate, and gold (Au) as a ground conducting layer with an electrical conductivity of 4.56e + 07 S/m. Additionally, we examine the impacts of various conductive materials, including aluminum, gold, copper, and iron, on the absorption response of the suggested MMA, in addition to the VO2. Furthermore, the influence of additional dielectric materials (lossy silicon and Al2O3) on the absorption response of the developed MMA is also examined alongside SiO2 The unit cell MMA functions at two absorption peak frequencies, 3.9 THz and 5.65 THz. The working frequency bands range from 3.09 THz to 4.61 THz and from 5.36 THz to 5.79 THz, achieving maximum absorption percentages of 98.2% and 98.7% in respective functional bands. The influence of incidence and polarization angles on absorbance is also demonstrated for TE and TM modes. A constant absorption bandwidth is achieved up to 70 degrees and 75 degrees of incident angles in TE and TM modes respectively. Similarly, a constant absorption bandwidth is achieved up to 80 degrees of polarization angles in both TE and TM modes. The recommended VO2-SiO2-Au-based MMA has potential for multiple terahertz applications including, biological sensing, imaging, cloaking, electromagnetic shielding, and detection.