Dual-band terahertz MIMO antenna using DGS for UWB applications

The rapid expansion of terahertz (THz) wireless technologies demands compact, high-performance antennas capable of operating over broad frequency ranges with minimal mutual coupling. In response, this work proposes a miniaturized dual-band multiple-input multiple-output (MIMO) antenna tailored for ultra-wideband (UWB) THz applications. To enhance impedance bandwidth and radiation efficiency, the design employs a Defected Ground Structure (DGS), which introduces deliberate discontinuities in the ground plane to suppress surface wave propagation. The proposed antenna exhibits a Mutual Envelope Gain (MEG) range between 0.35 and 0.50, a Total Active Reflection Coefficient (TARC) ranging from 0.5 to 2.5, and a Diversity Gain (DG) of 10, confirming its suitability for UWB MIMO performance metrics. Operating at 0.64 THz and 0.92 THz, the antenna achieves respective bandwidths of 0.12 THz and 0.26 THz, effectively covering the 0.5–1.05 THz range. Designed on a flexible polyimide substrate with a relative permittivity of 4.3 and loss tangent of 0.04, the antenna occupies a compact footprint of 0 . 4 × 0 . 8 mm 2 . The two-port MIMO configuration exhibits strong isolation, with an envelope correlation coefficient (ECC) of 0.006, indicating excellent diversity performance. Full-wave electromagnetic simulations performed using the High Frequency Structure Simulator (HFSS) confirm high impedance matching, with return losses of –56 dB and –30 dB, voltage standing wave ratios (VSWRs) close to 1, and peak gains of 19.56 dBi and 13.86 dBi. Compared to conventional THz antennas, the proposed design demonstrates a favorable balance of miniaturization, bandwidth, and MIMO isolation. Future work includes fabrication and experimental validation to confirm the simulation-based findings.