Investigation of graphene functionalized multi-band MIMO antenna with enhanced isolation with high gain for THz applications

This paper presents the development and analysis of a high-performance, optimized multiband, two-port Multiple-Input-Multiple-Output (MIMO) antenna with a dimension of 2.0517λ × 1.1737λ × 0.0132λ μm3, which is further extended up to a four-port antenna. The antenna design incorporates graphene, with a thickness of 0.34 nm in the patch and ground plane. It utilizes polyimide (ϵr = 3.5) as a substrate with a unique slot-loaded patch while also providing a thorough examination of their performance over five different substrate materials (Polyimide, Quartz, SiO2, Epoxy Regin, and Rogers RT6006). Initially, a basic patch antenna was built, then by incorporating various slots in the patch element the overall performance of the antenna was optimized. After that, an inverted L-shaped stub was integrated into the partial ground, and it was transformed into a 2-port parallel MIMO antenna. To enhance the performance further the antenna elements were positioned in an orthogonal arrangement. Furthermore, with the addition of metamaterial-inspired (MTM-inspired) shapes in between the antenna elements increase the level of isolation of about −90 dB. Finally, a corresponding four-port antenna was built and its performance characteristics were studied and compared with the two-port counterpart. The proposed two-port MIMO antenna demonstrates an exceptional reflection coefficient of −59 dB, accompanied by remarkable isolation of −90 dB, along with a gain of around 12.48 dBi. Moreover, crucial MIMO antenna performance metrices including Diversity Gain, Mean Effective Gain, Envelope Correlation Coefficient, Total Active Reflection Coefficient, and Channel Capacity Loss were also investigated to substantiate the proposed design. A thorough investigation of the proposed work in compared to the existing literature has been carried out, explicitly demonstrating the superiority of the proposed design. Overall simulation has been carried out using the CST Microwave Studio Suite.