Nano-Scaled Graphene Plasmonic-Based Vanadium Dioxide Yagi-Uda Array MIMO Antenna for Terahertz Applications

This paper presents the concept of nano-scaled graphene-based vanadium dioxide Yagi-Uda array multi–input–multi–output (MIMO) antenna for terahertz applications. The antenna design started with ground plane which is made up of PEC material. Further, substrate-1 and substrate-2 are placed above the ground plane. The nanostrip feedline is kept above the substrate-1 which is designed with the help of silver material. The feedline is sandwiched between substrate-1 and substrate-2. Additionally, vias is connected from the feedline to radiating elements. Further, the proposed antenna comprises the four sets of horizontal Yagi-Uda array radiating elements which consist of a reflector, dipole, and director. The array of elements has been made up of graphene and vanadium dioxide material. The array antenna has been excited to all four dipole elements with the help of vias. The proposed antenna generated the center frequency of 3.486 THz with the bandwidth of 22.56%. The efficiency and front-to-back ratio is calculated as 78.30% and 20.95 dB. The gain is calculated as 9.82 dB. The isolation between the ports is consistently sustained at a level exceeding − 15 dB within the operating passband. Furthermore, an analysis of the mode mechanism within the antenna is conducted, providing confirmation of the higher-order \({\varvec{T}}{{\varvec{M}}}_{22}\) $\mathit{T}{\mathit{M}}_{22}$ mode generation. Additionally, an examination of MIMO operational parameters, including mean effective gain (MEG), envelope correlation coefficient (ECC), total active reflection coefficient (TARC), and diversity gain (DG), has been analyzed, and the outcomes demonstrate a satisfactory level of concurrence. Later, the parametric analysis is carried out to assess the performance of the optimized geometry and to fine-tune the antenna’s response. The proposed MIMO structure has a potential application in THz applications.