Experimental Demonstration of Nonlinear Metasurfaces for High-Performance Low-Cost Near-Field Base Station

2D metamaterials (MTMs) or metasurfaces based on periodic arrays of high-Q coils have been long used as artificial magnetic lenses to boost the power transfer efficiency of inductive power transmission systems. In conventional linear topologies, this focalization effect is physically limited to extremely narrow bands due to the high Q of the unit cells. This paper, for the first time, experimentally demonstrates that nonlinear MTM lenses can produce a stable gain over a much wider bandwidth than any linear MTM lens. Such observation is validated with both continuous-wave and modulated excitations. Furthermore, the measurements also show that the group delay inside the gain region is almost linear, indicating that the proposed MTM lens presents very low in-band phase distortion. Such nonlinear MTM lenses are believed to find great potential in developing high- performance low-cost base station for near-field simultaneous wireless information and power transmission for many low-to- medium power applications.