Design of graphene-based broadband metamaterial absorber with circuit analysis approach for Terahertz Region applications

In this article, a compact metamaterial absorber exhibiting more than 80% absorption over a broad operating band ranging from 5.63 to 5.88 THz (250 GHz) is proposed for terahertz applications using circuit analysis approach. The novelty lies in designing a broadband absorber which features tunability while maintaining low profile dimensions (10 µm \(\times \) 10 µm). Concentric square ring-based graphene patches have been leveraged for providing metal-free absorption mechanism. The chemical potential of graphene has been varied from 0.4 to 1.0 eV to facilitate tunability in absorption. The proposed absorber has been rigorously analyzed with an Equivalent Circuit Model (ECM). The results obtained through full wave simulation and ECM approach are in good agreement and confirms the operation of the absorber at 5.75 THz. The peak absorption value of 99.96% is obtained at 5.75 THz. The proposed broadband terahertz absorber is suitable for sensing, imaging, biotechnology, polarization conversion, high-speed THz communications and food processing applications.