Design Method for Pixel Reconfigurable Intelligent Surfaces Using Internal Multi-Port Theory

Reconfigurable intelligent surfaces (RISs) are set to transform 6th generation (6G) communication networks by dynamically managing electromagnetic propagation. Traditional RIS designs typically utilize either metasurface technology, which is efficient but complex, or antennas with reconfigurable loads, which simplify control but capture only a limited range of electromagnetic waves. This paper introduces an alternative design approach based on internal multi-port theory for pixelated structures, offering a comprehensive methodology for designing RIS across various frequency bands and types. By incorporating RF switches in the optimization process and analytically calculating the scattered field, the proposed RIS elements achieve reduced complexity, optimized RF switch usage, and enhanced power utilization. This versatile method is applicable to various RIS types and holds significant potential for advancing future RIS designs.