Plasmonic-surface antenna systems are described in which resonators, or cells, are closely arranged but do not touch. At least a portion of a radiating surface includes a plurality of cells (operative as resonators) placed very close together to one so that a surface (plasmonic) wave causes near replication of the current of one cell in an adjacent cell. Cells with one or more fractal shapes may be used as a fractal plasmonic surface (FPS). Systems and/or methods are described of using plasmonic surfaces or fractal plasmonic surfaces for radiofrequency identification (RFID). A PS or FPS may act as an intermediary array of antennas, which can serve to connect an RFID reader with one or more RFID tags. Structures including cages are described that can include one or more surfaces that are each an FPS. Methods of power transfer are described.