Reconfigurable Intelligent Surface Using Liquid-Crystals for Precise and Wide-Angle Terahertz Beam Steering

This work presents a pixelated liquid-crystal-driven terahertz (THz) reconfigurable intelligent surface (RIS) with a vertical cross structure. The RIS array is composed of two metal metasurfaces with a liquid crystal (LC) embedded in between, having a 2-bit phase resolution. Each pixel subarray is independently controlled with a low voltage of 3.5V, using film-on-glass (FOG) technology integrated into quartz. The dynamic beam scanning in the two-dimensional plane can be realized by real-time encoding of subarrays under the control of a 2-bit digital coding sequence. A RIS prototype composed of 32 ×32 elements was manufactured and measured. The experimental results show that the device achieves 100° beam scanning with 1° of angular precision at 345 GHz. This device is expected to be useful in various applications, such as high-precision imaging, next-generation wireless communication, and other information systems.