Near-Field Focused Metasurface with Dual-Polarization and Multi-Focus Characteristics

This paper presents a new design of dual polarization near-field focused metasurface for high-efficiency wireless power transfer with multi-focus characteristics. The metasurface element consists of Jerusalem structure and four accompanying resonators surrounding them, and the linearity of the phase curve is improved by adjusting the ratio of the center resonator of the metasurface element to the accompanying resonator length, avoiding the impact of reducing the physical manufacturing accuracy on the focusing effect. In terms of focus phase synthesis of reflective metasurface, the metasurface with independent regulation of dual polarization is introduced to realize multi-focus and high-efficiency wireless power transfer. The dual polarization single-feed two-focus metasurface working at 11 GHz and 14 GHz with 15×15 elements are designed, fabricated and measured by planar near-field scanning experiments. Through full-wave simulation of two cases, operating at 11 GHz and 14 GHz, dual polarization single-feed two-focus can realize the maximum focusing efficiency of 69.8% and 70.8%, respectively. The relative bandwidth with 50% power focusing efficiency of these two cases are all over 18%. The measured results are in good agreement with the theoretical designs and simulated results, which verify the feasibility and correctness of the proposed approach in this paper.