Equivalent Resonant Circuit Modeling of a Graphene-Based Bowtie Antenna

Abstract

The resonance performance analysis of graphene antennas is a challenging problem for full-wave electromagnetic simulators due to the trade-off between the computer resource and the accuracy of results. In this paper, an equivalent circuit model is presented to provide a concise and fast way to analyze the graphene-based THz bowtie antenna. Based on the simulated results of the frequency responses of the antenna, a suitable equivalent circuit of Resistor-Inductor-Capacitor (RLC) series is proposed to describe the antenna. Then the RLC parameters are extracted by considering the graphene bowtie antenna as a one-port resonator. Parametric analyses, including chemical potential, arm length, relaxation time, and substrate thickness, are presented based on the proposed equivalent circuit model. Antenna input resistance R is a significant parameter in this model. Validation is performed by comparing the calculated R values with the ones from full-wave simulation. By applying different parameters to the graphene bowtie antenna, a set of R, L, and C values are obtained and analyzed comprehensively. A very good agreement is observed between the equivalent model and the numerical simulation. This work sheds light on the graphene-based bowtie antenna’s initial design and paves the way for future research and applications.

A Review on the Development of Tunable Graphene Nanoantennas for Terahertz Optoelectronic and Plasmonic Applications

“…Remember that this electrostatic method estimates the graphene sheets as an infinite ideal conductor to calculate the carrier densities. Merging Equations (14)- (16), the chemical potential of each graphene layer can be found through [78]…”

“…The equivalent circuit per unit length is introduced in [62], where the author calculated the analytical expression for the graphene conductivity and circuit lumped components and illustrated the propagation of surface waves along spatial graphene waveguides. Recently, the equivalent resonant circuit model was designed by Zhang et al for the validation of simulated results, and extracted resistive, inductive, and capacitive (RLC) parameters by considering the graphene bowtie antenna as one port resonator [78]. Additionally, the partial element equivalent circuit (PEEC) method is utilized for designing the equivalent circuit of the graphene-based terahertz antenna [99].…”

Dynamic Absorption Enhancement and Equivalent Resonant Circuit Modeling of Tunable Graphene-Metal Hybrid Antenna

“…It is important to note that this electrostatic method estimated the graphene sheets as an infinite ideal conductor to calculate the carrier densities. Merging Equations (5)-(7), the chemical potential of each graphene layer can be found through [34],…”

“…Contrarily, the carrier density is generally associated with the applied external electrostatic bias field. Consequently, the chemical potential is identified with applied biasing voltage through carrier density [34]. The gate bias is applied between the graphene stack and dielectric media to tune and actively control the conductivity [41].…”

“…The resonant circuit models need to be developed to extend the knowledge on graphene antennas and to validate the simulations results to reveal insight into the parametric functionality of graphene antenna along with the physical understanding of resonant properties. Zhang et al [34] proposed a simple RLC circuit model to explain antenna characteristics, i.e., resonance frequency and quality factor. For this purpose, they first consider the antenna input impedance with a series RLC circuit and treat the antenna as a coupled-resonator to optimize the RLC circuit values for resonance condition.…”