Mutual Coupling Reduction between FSS Decoupling Structure and Nanoantenna Array-Elements in THz Multi-Band Plasmonic UM-MIMO

This study introduces a novel methodology for mitigating mutual coupling in Terahertz (THz) multi-band Ultra-Massive Multiple-Input Multiple-Output (UM-MIMO) systems, specifically focusing on plasmonic nanoantenna arrays. The primary objective is to reduce the interference between Frequency Selective Surface (FSS) decoupling structures and adjacent nanoantenna array elements, which is critical for optimizing THz communication system performance. The research involves the design and characterization of new FSS structures and nanoantenna array geometries, employing advanced materials to enhance mutual coupling reduction. By precisely tuning the array geometry and refining the FSS decoupling structure, the study achieves a significant reduction in mutual coupling, with a frequency offset improvement of 4.7% relative to baseline frequencies. Furthermore, the integration of the optimized nanoantenna array with the FSS structure yields substantial reductions in return loss, with S11 and S22 values reaching approximately -7 dB and -8 dB, respectively. The proposed design also demonstrates a compact and stable configuration, achieving a uniform mutual coupling reduction of approximately -22 dB and FSS decoupling structure. This work provides a robust and efficient solution for enhancing the performance and reliability of multi-band THz UM-MIMO systems.