Quartz Substrate-Based Super Absorber Using Graphene Material with 18 Absorption Bands for Terahertz Applications

Over the last decade, researchers from all over the world have become very much interested in the terahertz gap, which has a frequency range of 0.1 to 10 THz. The terahertz band can be regarded as the next frontier for wireless communications. This work is related to the design of an octagonal-shaped metasurface-based multiband super absorber for various applications in the terahertz regime. The proposed metasurface unit cell has been configured with a simple design that contains only three different layers and achieves 18 absorption peaks with more than 90% absorption levels. The desired geometry has been structured by using an octagon-shaped graphene-based radiating patch, a quartz substrate material as a dielectric space layer, and, finally, a golden patch at the bottom layer to prevent electromagnetic wave transmission. The thickness of the golden layer is taken as 0.2 µm, the thickness of the quartz substrate material is selected as 55 µm, and the thickness of graphene is considered as 1 nm. The overall size of the proposed unit cell becomes 70 × 70 × 55.201 µm³. The better performance of the proposed metasurface absorber can be obtained by fixing the chemical potential of graphene material at 0.3 eV. The proposed absorber also exhibits a polarization-insensitive nature. Additionally, the structure is also validated through an equivalent circuit approach with the support of the ADS tool and both E- and H-field distributions are explained at each absorption peak frequency. The proposed structure’s metamaterial properties demonstrate the absorber’s metamaterial nature. Based on the findings, the proposed metamaterial perfect absorber could be a suitable choice for terahertz sensing, imaging, and high-speed communication applications.