Design, Measurement and Analysis of Near-Field Focusing Reflective Metasurface for Dual-Polarization and Multi-Focus Wireless Power Transfer

Pei Zhang,Long Li,Yan Shi,Xuanming Zhang,Haixia Liu

doi:10.1109/access.2019.2934135

Pei Zhang, Long Li + Show 3 more

Open Access

https://doi.org/10.1109/access.2019.2934135

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Abstract

A new design of dual-polarization and multi-focus near-field focusing (NFF) reflective metasurface for wireless power transfer (WPT) system is proposed in this paper. In terms of multi-beam phase synthesis of reflective metasurface, the dual-polarization metasurface with independent regulation characteristics is introduced to realize multi-focus and high-efficiency WPT. The single-feed single-focus and the single-feed dual-focus metasurface working at X-band (10 GHz) with $26\times 26$ elements in two polarizations are designed, fabricated and measured by planar near-field scanning experiments. Furthermore, a compact antenna is designed and fabricated as the receiver to form a practical WPT system. The measurement results show that a NFF transfer system is 15 dB higher than a non-NFF transfer system. Through full-wave simulation and experiments of three cases, single focus, dual-focus, and single focus with dual-polarization can respectively realize the maximum focusing efficiency of 71.6%, 68.3% and 65.9%. The relative bandwidth with 50% power focusing efficiency of these three cases are all about 12%, which demonstrates the stability and feasibility of the NFF reflective metasurface for practical WPT applications.

Highlights

Since electric energy has become the main energy source in human society, it has always been a dream to realize wireless power transfer (WPT)
MULTI-BEAM PHASE SYNTHESIS THEORY The model schematic diagram of the near-field focusing (NFF) reflective metasurface shown in Fig. 3 is with the function of multi-feed power synthesis and multi-focus power distribution, which can realize the spatial diversity of wireless power
This paper presents a new design of NFF reflective metasurface which can realize multi-focus and high-efficiency power transfer

Summary

INTRODUCTION

Since electric energy has become the main energy source in human society, it has always been a dream to realize wireless power transfer (WPT). Each element of the metasurface is phase-compensated according to its optical path difference compared with an in-phase point in space, that beam direction can be controlled, which makes the power focused in an aperture within the near-field region. The above is a good verification of the dual-polarization independent regulation characteristics of the cross-dipole element, so that different focus positions and focusing functions can be set according to the change of polarization of the incident waves, which further broadens the applications of the reflective metasurface. MULTI-BEAM PHASE SYNTHESIS THEORY The model schematic diagram of the NFF reflective metasurface shown in Fig. 3 is with the function of multi-feed power synthesis and multi-focus power distribution, which can realize the spatial diversity of wireless power.

CASE1: SINGLE-FEED AND SINGLE-FOCUS WITH DUAL-POLARIZATION

CONCLUSION