Commercial RFIDs as Reconfigurable Intelligent Surfaces

Reconfigurable Intelligent Surfaces (RISs) are emerging as cost-effective solutions for enhancing signal transmission in wireless networks. Traditional RIS designs, however, face challenges such as bulkiness, high production costs, limited scalability, and intricate installation due to their reliance on wired connections. In this work, we innovate by repurposing 920MHz RFID tags into battery-free unit cells, creating an affordable, scalable, and flexible one-bit phase-modulated RIS. This novel system, referred to as MetaMosaic, is engineered for compatibility with 2.4GHz Wi-Fi communications while being controlled at a 920MHz frequency. Our approach is distinguished by two primary innovations: the conversion of RFID tags into functional unit cells, and the development of a bespoke neural radiance field to identify the most effective reconfiguration strategy. We constructed six MetaMosaic surfaces, each comprising 403 cells, using a total of 2,418 repurposed RFID tags at a cost of 50 cents per tag. Our extensive testing in ten varied environments demonstrates that MetaMosaic substantially boosts signal strength, achieving a mean of 19dB gain (i.e., 80 ×) over non-RIS setups. This outperforms current leading RIS systems by a 3-fold improvement. In the context of XR application, the field study showcases a more than doubling of throughput and a halving of latency.