Ambient-energy-driven space-time-coding metasurface for space-frequency-division multiplexing wireless communications
Programmable metasurfaces have demonstrated potential for dynamic electromagnetic wave manipulation, yet their large-scale deployment is constrained by high communication capacity demands and stringent energy requirements. This work presents an ambient-energy-driven space-time-coding metasurface that achieves space-frequency-division multiplexing while operating self-sufficiently via integrated solar energy harvesting. The metasurface dynamically controls multiple frequencies and spatial propagation directions of reflected waves, enabling four independent communication channels. A four-channel wireless communication prototype transmitted four distinct images to separate user terminals simultaneously and in real time, with energy consumption per bit markedly lower than conventional programmable metasurfaces. The shared-aperture design integrates ambient solar harvesting and low-power programmable elements, eliminating external power supplies. Experimental validation confirms independent multichannel operation with low inter-channel interference. This platform merges ambient energy harvesting, multidimensional microwave manipulation, and direct information modulation on a single physical layer, offering a cost-effective, energy-efficient, and environmentally friendly pathway for high-capacity wireless communications. The results establish a foundational architecture for self-powered reconfigurable intelligent surfaces in next-generation networks.