Demonstration of Optoelectronic THz Beam Tracking Using Real-Time Phase Optimization

Addressing the critical beam alignment challenge in Terahertz (THz) communications for 6G, this letter details the implementation of 300 GHz beam tracking using an arrayed antenna. Despite the efficiency of beamforming, narrow THz beamwidth demands precise alignment. Our system uniquely combines an optical phased array with a real-time algorithm that optimizes the beam direction based on received power feedback. We experimentally validated the system's effectiveness. First, successful static beam optimization was demonstrated, achieving a synthesis gain of 11.5 dB, which approaches the theoretical limit. Furthermore, beam tracking was achieved for a receiver moving within an angular range of ±40° at angular velocities up to 3.58 deg/s. Throughout the tracking process, the arrayed antenna demonstrated a stable mean synthesis gain of 9.11 dB. This successful demonstration provides a viable pathway to enhance the robustness and efficiency required for future THz mobile communication networks.