In the realm of communication and measurement using terahertz waves, two-dimensional beam scanning in the air is essential. However, the implementation remains challenging in the terahertz frequency band, where no low-loss, broadband phase shifters are available. In this study, we have proposed and demonstrated a new technique for realizing two-dimensional beam scanning with terahertz waves. Specifically, we utilized two degrees of freedom (2-DOF) in terahertz beam steering by radiating a formed terahertz wavefront into external space as a leaky-wave beam. We achieved this by controlling both the frequency sweep and the gradient of the conductor plate. Initially, we substituted the upper flat plate with a mesh layer to allow for wave leakage. We then demonstrated that the beam could be scanned vertically by sweeping the frequency and horizontally by adjusting the relative inclination between the plates, exploiting the spatial gradient of the effective refractive index. By integrating these two methods, we have proven that the beam can be scanned with two degrees of freedom.
- Kazuto Sato and Yasuaki Monnai. “Two-Dimensional Terahertz Beam Steering Based on Trajectory Deflection of Leaky-Mode,” IEEE Transactions on Terahertz Science and Technology, vol. 11, no. 6, pp.676-683, 2021.
- Kazuto Sato and Yasuaki Monnai, “Terahertz Beam Steering Based on Trajectory Deflection in Dielectric-free Luneburg Lens,” IEEE Transactions on Terahertz Science and Technology, vol. 10, no. 3, pp. 229-236, 2020.