Design and Simulation of Dual-Band Four-Port Graphene MIMO Antenna Array for Wireless Communication at 2.88/4.36 THz

In this manuscript, a graphene-based four-port linear MIMO antenna is proposed for terahertz (THz) applications. The antenna is designed on a polyimide substrate with a compact footprint of 60 µm × 240 µm × 4 µm. A modified triangular patch with a tip-fed configuration is employed to enhance asymmetric current distribution, enabling dual-band operation at 2.88 THz and 4.36 THz. A parametric analysis is carried out by varying the chemical potential and relaxation time of graphene to optimize the antenna performance in terms of S-parameters. The proposed design achieves an inter-element isolation > 20 dB, with a realized gain exceeding 3.28 dBi and radiation efficiency above 65% across both operating bands. Furthermore, key MIMO diversity parameters are evaluated, demonstrating an envelope correlation coefficient (ECC) ≤ 0.008 and channel capacity loss (CCL) ≤ 0.27 bits/s/Hz over the entire operating range. The total active reflection coefficient (TARC) remains stable under varying excitation phase conditions, indicating minimal mutual coupling between adjacent ports. An equivalent circuit model is also developed to validate the simulated results. The antenna is analyzed using CST Microwave Studio, and the obtained results confirm its suitability for emerging THz near-field applications.