Demonstration of 2D Optoelectronic THz-Wave Beam Steering

Advanced two-dimensional (2D) beam steering is essential for unlocking the full potential of terahertz (THz) systems in future 6G communications and high-resolution imaging. However, achieving wide-angle, high-speed, and high-precision 2D beam control within a compact THz platform remains a significant challenge. In this work, we experimentally demonstrate an optoelectronic 2×2 THz antenna array that enables flexible 2D beam steering, beam hopping, and beam scanning around the 300 GHz band. This work employs a 2×2 microstrip patch antenna (MPA) array directly driven by InGaAs/InP UTC-PDs on a silicon carbide (SiC) substrate. The relative phases of the four radiating elements are precisely programmed using an optical phased array (OPA), which provides fully decoupled and low-latency phase control in the optical domain. Experimentally, we demonstrate 2D beam steering and 2D beam hopping among three representative directions at a polar angle of 25∘ and azimuth angles of 60∘, 180∘, and 300∘. Furthermore, continuous 2D beam scanning at a fixed polar angle of 25∘ is achieved, enabling a full 360∘ azimuth sweep within 0.43 s while maintaining high beam quality. These results confirm that the proposed UTC-PD based 2×2 MPA array provides a practical and robust approach for 2D THz beam manipulation, and offers strong potential for future 6G wireless links and THz imaging applications.