Reconfigurable Intelligent Surfaces (RIS) show great potential for mitigating blind signal areas by redistributing the radio wave field. However, achieving scalability and high-power efficiency remains a challenge. Our research focuses on leveraging mature liquid crystal display (LCD) manufacturing technologies for RIS, aiming to reduce costs, lower power consumption, and enable mass production, thereby facilitating high coverage for future 6G communication systems. Our research can be divided into three main areas: liquid-crystal phase shifters, liquid-crystal reconfigurable intelligent surfaces, and transparent antennas.

Liquid-Crystal Phase Shifter

　　Our research team has developed a reflective-type 3.5GHz LC phase shifter, designed using a differential pair transmission line periodically loaded with floating electrodes, where the liquid crystals in the overlapping area function as a variable capacitor. By applying an electric field, the permittivity of the liquid crystals is adjusted, enabling precise phase modulation. The design complies with LCD manufacturing process, achieving a phase shift of 282°, with FoM of 85.7˚/dB.

arXiv:2406.15023 [physics.app-ph], https://doi.org/10.48550/arXiv.2406.15023 (Under Submission for MOTL)

Liquid-Crystal Reconfigurable Intelligent Surfaces

　　Our team has developed an innovative LC-based Reconfigurable Intelligent Surface (RIS) leveraging an LC phase shifter and dipole antennas as radiating elements. By sharing a differential signal between the transmission line and dipole antenna, our design eliminates the need for additional coupling layers or baluns, simplifying the structure. This streamlined approach aligns seamlessly with LCD manufacturing processes, making it cost-effective and scalable for practical applications..

Transparent Antenna on Glass

　　To achieve transparency in future LC RIS, we have developed transparent antennas using meshed metallic structures and established metal-related processes on glass substrates. This work explores the practical efficiency of transparent antennas and evaluates their feasibility for integration into RIS applications.