Wireless power transfer system adaptive to change in coil separation

Juseop Lee, Yong Seok Lim, Woo Jin Yang, Seung Ok Lim

Research output: Contribution to journalArticlepeer-review

59 Citations (Scopus)


In this paper, we present a wireless power transfer (WPT) that is adaptive to change in coil separation. For analytic design of the WPT system, a new design method which does not require calculating the voltages and currents in the system is presented. The proposed design method allows us to have perfect impedance matching theoretically for the WPT system using capacitor circuits connected to the sending and receiving coils. Closed-form design equations are provided for straight-forward application of the new design method. In order to compensate the variation of the mutual coupling between the two coils due to the change in separation, we propose a new switchable capacitor array circuit. For verification of the new design method and the new switchable capacitor array circuit, we have fabricated and measured a WPT system operating at 370 kHz. Measured results have shown a good agreement with theoretical responses, and the reflected power ratio smaller than 3% has been achieved by using the proposed switchable capacitor array circuit over the 5:1 change of coil separation.

Original languageEnglish
Article number6663679
Pages (from-to)889-897
Number of pages9
JournalIEEE Transactions on Antennas and Propagation
Issue number2
Publication statusPublished - 2014 Feb


  • Admittance inverter
  • impedance matching
  • resonant coils
  • wireless power transfer

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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