Electronic Control of Directional Properties of Reconfigurable Plasmonic Graphene-Based Antenna Arrays with Frequency Scanning in the Mid-IR Range

Abstract

Mid-IR antennas can play a critical role in advancing discoveries and innovations for applications such as IR wireless communications, imaging and visualization, remote sensing including environmental and biological, remote detection, security scanning, biomedical applications and astronomy, the Internet of Things, and sensors. The aim of the work is to study using the CST MWS 2023 software package the electronic control of the directional properties of reconfigurable plasmonic graphene antenna arrays, i.e., the main beam of the radiation pattern (RP), by using electrical frequency tunability by changing the chemical potential of graphene (by applying an external electric field), scanning the RP and changing the shape and parameters of the RP in the mid-IR range. In the mid-IR range, graphene exhibits plasmonic-like complex surface conductivity with low losses, which provides great potential for the development of tunable antenna arrays in this range. Research on the application of surface plasmon polaritons (SPPs) in graphene is focused on the ranges from terahertz to mid-IR, since current technologies allow reducing the width of graphene nanoribbons only to such an extent that they can excite plasmonic oscillations in the mid-IR range. To solve the electrodynamic problem using the CST MWS 2023 program, designed for numerical modeling of high-frequency antennas and devices, the Perfect Boundary Approximation (PBA) method is used, complementing the Finite Integration Technique (FIT) method, which works in the time domain. The results of electrodynamic modeling of the controllability of the RPs of plasmonic graphene antenna arrays with different numbers of emitters and electronic frequency scanning at the resonant frequencies of the fundamental SPP mode in the mid-IR range were obtained with a change in the value of chemical potential μ_c (0.3–1 eV) and their dependence on the geometric dimensions of the graphene elements and the antenna array periods. As a result of electrodynamic modeling, the possibility of effective electronic control of RPs of the plasmonic graphene antenna arrays in the scanning regime in the mid-IR range with a change in the chemical potential of graphene (μ_с = 0.3–1 eV) is shown: a change in the direction of the main lobe of the RPs, while the achievable sector of the scanning angles confirms the efficiency of beam control; a decrease in the width of the RPs at the half-power level and the level of side lobes; an increase in the radiation efficiency and, as a consequence, an increase in the gain.