A GaN Schottky Barrier Diode‐Based Terahertz Metasurface for High‐Precision Phase Control and High‐Speed Beam Scanning

Abstract

Abstract Effective wavefront control in the terahertz (THz) regime is essential for achieving high‐directionality beamforming, spatial multiplexing, and real‐time wireless communication. However, low‐loss, precise, and rapid THz phase modulation remains fundamentally constrained by material limitations and inherent device‐level trade‐offs. A programmable THz metasurface (GaNMS) is presented, employing a gallium nitride Schottky barrier diode with a high‐mobility 2D electron gas, specifically designed to overcome these limitations by leveraging its low insertion loss, fast response, and continuously tunable junction capacitance. A 32 × 25‐element array is designed and fabricated. Each unit cell functions as a direct THz phase shifter, dynamically tuning the junction capacitance to enable continuous phase modulation from 0° to 210° at 0.32 THz, with a 1.8° average phase error, modulation speed exceeding 200 MHz, and ≈5 dB average insertion loss. To mitigate array‐level nonuniformities, a differential evolution‐based optimization algorithm is introduced, enabling robust ±45° beam scanning in both analog and digital modes, with main lobe gains of 18.5 and 16 dBi, respectively. An integrated GaNMS‐based sensing and communication system is also demonstrated, validating its potential in next‐generation THz applications. The proposed GaNMS bridges device‐level phase tunability and system‐level functionality, enabling practical THz technologies.