Abstract-Cascaded Graphene Frequency Selective Surface Integrated Tunable Broadband Terahertz Metamaterial Absorber

Rishi Mishra, Madhya Pradesh,  Arpit Sahu,  Ravi Panwar

https://ieeexplore.ieee.org/document/8660511

The quest of novel materials and structures to design an efficient absorber for realizing wave trapping and absorption at terahertz (THz) frequencies is an open topic. But the design of a thin, wideband and tunable THz absorber is still an arduous job. Hence, in this work, a hybrid THz metamaterial absorber (THz-MMA) integrated with a cascaded graphene frequency selective surface (FSS), with ultra-high absorbance over a wide frequency range is designed using an analytical equivalent circuit model (ECM). A systematic study and critical analysis over a wide range of device parameters including graphene chemical potential and FSS design variables is demonstrated. A peak dip in reflection coefficient (RC) of -30.27 dB is observed at 2.94 THz for an optimal device with a chemical potential (μc) of 0.38 eV (μc1) , and 0.25 eV (μc2) . The cascaded FSS configuration results in unique anti-reflection based absorption phenomena, which is responsible for the achievement of -10 dB absorption bandwidth of 2.34 THz (0.85-3.19 THz). In addition, the frequency dependent effective permittivity, permeability and impedance is extracted using reflection data, in order to understand the device physics. Such ultra-thin and broadband absorbing device architecture may confer potential application perspectives in THz sensing, imaging and detection