Thin Hybrid Metamaterial Slab with Negative and Zero Permeability for High Efficiency and Low Electromagnetic Field in Wireless Power Transfer Systems


Current wireless power transfer (WPT) systems have limited charging distance and high induced electromagnetic field (EMF) leakage. Thus, we first proposed a thin printed circuit board (PCB) type hybrid metamaterial slab (HMS) combining two kinds of metamaterial cell structures. The metamaterial cells in the center area of the HMS have zero relative permeability and straighten the magnetic field direction. The metamaterial cells located at the edges of the HMS have negative relative permeability and change the outgoing magnetic fields to opposite direction by magnetic boundary condition. Therefore, the magnetic field can be more confined between transmitter and receiver coils, enhancing the power transfer efficiency, while decreasing the EMF leakage in a WPT system. In this paper, we demonstrated that increased power transfer efficiency from 34.5% to 41.7% and reduced EMF leakage from -19.21 to -26.03 dBm in 6.78-MHz WPT system. Furthermore, we proposed new analysis method for relative permeability measurement of the metamaterial using a novel cubic structure with perfect electrical conductor and perfect magnetic conductor boundary.


Electrical and Computer Engineering

Research Center/Lab(s)

Electromagnetic Compatibility (EMC) Laboratory

Keywords and Phrases

Efficiency; electromagnetic field (EMF); hybrid; magnetic field forming; magnetic field scanner; metamaterials; negative permeability; wireless power transfer (WPT); zero permeability

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version


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© 2018 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Aug 2018