Implementing an active reconfigurable intelligent surface with a thin liquid crystal layer through 1-bit quantization

This paper proposes a proof-of-concept design for a Reconfigurable Intelligent Surface (RIS) using Liquid Crystals (LC) and Corning glass for wireless communication applications. The proposed RIS consists of specially designed copper-coated glass substrates and LC materials sandwiched between the two glass substrates. The LC layer, which is 20 μm thick, is positioned between the upper and lower Corning glass sheets. Although the 20 μm cell gap is very thin compared to the operating frequency (previous research used gaps greater than 100 μm), we achieved a phase shift of more than 180° by applying 10 V within the designed frequency band. Our proposed concept can enhance wireless communication coverage by reflecting incident electromagnetic waves in the desired direction, thereby securing a propagation path by simply changing the alignment of LC molecules under different driving voltages. Additionally, conventional LCD manufacturing technology can significantly reduce costs and support larger sizes compared to existing semiconductor-based electronics and Printed Circuit Board (PCB) processing.