Graphene–Polyimide Flexible Electronic Platform Enabling Ultra‐Broadband High‐Gain THz MIMO Systems

The integration of two‐dimensional (2D) materials with flexible substrates is pivotal for advancing next‐generation terahertz (THz) and sixth‐generation (6G) wearable electronics. However, a significant challenge remains in preserving the exceptional electronic properties of 2D materials such as graphene on low‐loss, mechanically robust dielectrics at high frequencies. This work introduces a graphene–polyimide hybrid platform that synergizes the tunable plasmonic conductivity of monolayer graphene with the outstanding flexibility and low dielectric loss of polyimide. Comprehensive material characterization, including Raman spectroscopy, SEM, AFM, and bending tests, confirms high‐quality, uniform graphene integration with excellent electrical and mechanical stability (sheet resistance variation < 1.2% after 1000 bending cycles). To demonstrate the platform’s potential, we designed and simulated a compact dual‐band THz MIMO antenna. The antenna operates across 2.96–3.95 THz and 4.6–10 THz, achieving a peak gain of 14.3 dB, radiation efficiency exceeding 97%, and interelement isolation greater than 31 dB, with an envelope correlation coefficient (ECC) below 0.0002. Unlike prior 6G antennas that rely on rigid substrates or limited GHz prototypes, this work demonstrates the first graphene–polyimide MIMO platform achieving verified ultra‐broadband operation from 2.96 to 10 THz with high efficiency (> 97%) and strong isolation (> 31 dB). These results, validated through full‐wave electromagnetic and circuit‐level simulations, confirm that the graphene–polyimide platform effectively minimizes ohmic and dielectric losses while ensuring high performance and flexibility. This work establishes a scalable pathway for developing next‐generation THz components, such as antennas, sensors, and tunable plasmonic devices, highlighting the critical role of 2D material integration in future flexible electronic systems. The demonstrated performance validates a scalable path toward flexible, high‐gain, and low‐loss THz systems for 6G front‐end and IoT applications.