Quad-band polarization sensitive terahertz metamaterial absorber using Gemini-shaped structure

In this article, we design a metamaterial absorber (MMA) to provide quad-band absorption characteristics in terahertz range. The proposed MMA structure comprises of a Gemini-shaped resonator, graphene, SiO2 and metallic plane demonstrating multiple peaks at 1.29, 3.32, 3.85, and 4.56 THz with absorptivities greater than 90%. The absorption mechanism can be attributed to the high-order resonances analyzed by the electric field distribution. Further, simulated results are verified using equivalent circuit model and the obtained results are in well accordance with the simulated results. The proposed absorber is further analyzed with various polarization angles suggesting that absorber is polarization sensitive due to its symmetrical shape of the resonator. The compactness and thickness of the proposed design is 0.207λ and 0.047λ, respectively, which is better than earlier reported absorbers. The Gemini shaped absorber can be utilized in various fields including sensing, detection and imaging.