Reconfigurable Coil Array for Near-Field Beamforming to Compensate for Misalignment in WPT Systems

Taejun Lim, Yongshik Lee

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


This work develops a reconfigurable coil array that compensates for the misalignment between coils in magnetic resonance coupled wireless power transfer (WPT) systems. By tuning the magnitude of the currents induced in the coil array with the variable capacitors that load them, the effect of reconfiguring the size and/or shape of the coil can be achieved. Therefore, the near field can be steered in a certain direction to overcome the notorious misalignment problem in WPT systems. For experimental demonstration, a 2× 1 array is designed and fabricated for a 60× 60 mm2 coil. For a vertical distance between Tx and Rx coils of 10 mm, which is 16.7% of the largest coil dimension, the transfer efficiency maintains more than 40% and up to 141.6% misalignment. This is more than an 81% increase over the conventional coil. For a vertical distance of 30 mm or 50%, the minimum transfer efficiency is 37.1% up to 100% misalignment, which is almost 5.5 times that of the conventional counterpart. The results suggest that the demonstrated technology successfully overcomes the notorious misalignment problem in both short-range and midrange WPT systems and even in asymmetric systems where the reconfigurable coil array technique is applied only on the Rx.

Original languageEnglish
Pages (from-to)4711-4719
Number of pages9
JournalIEEE Transactions on Microwave Theory and Techniques
Issue number11
Publication statusPublished - 2021 Nov 1

Bibliographical note

Funding Information:
This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 020R1A2C1010251).

Publisher Copyright:
© 1963-2012 IEEE.

All Science Journal Classification (ASJC) codes

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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