A 7.1-8.4 GHz Slant Dual-Polarized High-Aperture-Efficiency Reconfigurable Intelligent Surface for 6G FR3 Systems

This paper presents a 256-element 7.1-8.4 GHz high-aperture-efficiency slant dual-polarized reconfigurable intelligent surface (RIS) for 6G FR3 systems. Each RIS unit employs a 2-bit reflect phase shifter for each polarization using low-loss commercial SP4T switches. A dual-polarized triple-stacked patch antenna is implemented to meet wide FR3 operational bandwidth. The array follows an N×N scalable architecture and can be extended to 1024-element using a 2×2 tiling approach. The RIS supports 10 µs fast beam switching to satisfy real-time communication requirements. Measurement results demonstrate far-field reflective beam steering capabilities with an EVM < 2% and an aperture efficiency of 42% at 8 GHz. The work demonstrates the lowest loss RIS to-date and with a very wide scan angle.