Numerical analysis on transmission efficiency of evanescent resonant coupling wireless power transfer system

Qiaowei Yuan, Qiang Chen, Long Li, Kunio Sawaya

Research output: Contribution to journalArticlepeer-review

138 Citations (Scopus)


A practical wireless power transmission system consisting of a large rectangular wire loop and a small square wire loop with a parasitic square helical coil is proposed for use as an efficient evanescent resonant coupling wireless power transmission system in an indoor environment. In addition, a full wave-based numerical analysis on the resonant frequency of and the power transmission efficiency of wireless power transmission system are performed in this paper. The effects of the following on power transmission efficiency and the resonant frequency are numerically investigated: The load of the receiving element and the presence of non-resonant objects such as a conducting box or human body. The numerical results show that a power transmission efficiency of nearly 50% can be achieved when the proposed system is used to charge only one user with the optimized load. The results also show that power transmission efficiency is reduced significantly when a human body is in very close proximity to the receiving element. This reduction in efficiency can be alleviated significantly, however, if the relative distance between the receiving element and the human body is greater than 0.5 m or 0.03λ at a resonant frequency of 19.22 MHz.

Original languageEnglish
Article number5422616
Pages (from-to)1751-1758
Number of pages8
JournalIEEE Transactions on Antennas and Propagation
Issue number5
Publication statusPublished - 2010 May


  • Efficiency
  • Evanescent
  • Human body
  • Power transfer
  • Resonant
  • SAR
  • Wireless

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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