This study presents a circuit model of graphene- and carbon nanotube (CNT)-based multilayer devices using transmission line theory (TLT). In case of graphene-based stacks, graphene sheets were modelled as parallel R-L-C circuits. In case of CNT-based stacks, CNTs were modelled as a combination of series and parallel RLC circuits. The variables investigated in this work were thickness of the dielectric layer, nature of graphene (monolayer versus bilayer versus four layers), and the number of stacks. Through the determination of input impedance of the corresponding equivalent circuits and the resulting relation between absorbance and reflection coefficient, we find that the absorption frequency of graphene-based multilayer structures ranges from 180 GHz to 1 THz. But the CNT-based multilayer stacks show absorption resonance peaks ranging from 30 to 35 THz. Furthermore, we demonstrate that the absorption peek's frequency can be tuned suitably via optimization of multilayer stack design and the dielectric thickness.
S. V. Suriya, Avinash, J., Nair, B. B., and Dr. T. Rajagopalan, “Circuit Modelling of Graphene and Carbon Nanotube-Based Multilayer Structures for High-Frequency Absorption”, Advances in Electrical and Computer Technologies, vol. 672 (Part of the Lecture Notes in Electrical Engineering (LNEE) book series. Springer Singapore, Singapore, 2020.