Modeling the Controllability of Performances of Plasmon Graphene Nanoantenna Arrays in the Mid-IR Range

Abstract

The implementation of nanoantennas for optical wireless communications in the infrared (IR) and visible ranges ensures higher data transfer rates, reducing simultaneously the antenna size. The possibility to tune the performances of graphene by chemical doping or bias voltage is relevant in the development of reconfigurable nanoantennas. The goal of this research is the study of the performances (S‑parameters and radiation patterns (RPs)) of plasmonic graphene nanoantenna (PGNA) arrays, their controllability, and the possibility of frequency scanning by changing the chemical potential of graphene (by applying an external electric field) in the mid-IR range. The use of graphene, which has a controlled high electrical conductivity, and plasmonic properties in the terahertz (THz), far-IR and mid-IR ranges is one of the most promising alternatives to noble metals (Au and Ag) as plasmonic materials at optical frequencies only. Modeling the performances of PGNA arrays was carried out using the electrodynamic modeling program CST Microwave Studio 2023, which makes it possible to solve scientific problems associated with the design of graphene antennas in the IR wavelength range. The results of modeling the controllability of the characteristics (S‑parameters, RPs) of a single element of the antenna array (PGNA of rectangular geometry) and PGNA arrays at the resonant frequencies of the fundamental mode of surface plasmon polaritons (SPPs) are obtained, and the possibility of scanning in frequency upon a change in the chemical potential of graphene (by applying an external electric fields) in the mid-IR range is demonstrated. The results of modeling the performances of PGNA arrays show that with an increase in the chemical potential of graphene (in the interval of values of 0.3–1 eV), the operating frequencies are adjusted (frequency scanning) in the mid-IR range, the gain of the PGNA array increases, the RP main lobe narrows, and the RP side lobe level decreases with an increase in the number of single elements (N = 256); and better controllability of the RP main lobe is observed.