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Room-scale magnetoquasistatic wireless power transfer using a cavity-based multimode resonator

Nature Electronics volume 4, pages 689–697 (2021)Cite this article

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Abstract

Magnetoquasistatic wireless power transfer can be used to charge and power electronic devices such as smartphones and small home appliances. However, existing coil-based transmitters, which are composed of wire conductors, have a limited range. Here we show that multimode quasistatic cavity resonance can provide room-scale wireless power transfer. The approach uses multidirectional, widely distributed currents on conductive surfaces that are placed around the target volume. It generates multiple, mutually unique, three-dimensional magnetic field patterns, where each pattern is attributed to different eigenmodes of a single room-scale resonator. Using these modes together, a power delivery efficiency exceeding 37.1% can be achieved throughout a 3 m × 3 m × 2 m test room. With this approach, power exceeding 50 W could potentially be delivered to mobile receivers in accordance with safety guidelines.

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Fig. 1: Overview of M-QSCR.
Fig. 2: Constructed room-scale resonator.
Fig. 3: Evaluation of power transfer efficiency.
Fig. 4: Evaluation of safety based on SAR.
Fig. 5: Demonstration of room-scale wireless power transfer in a living environment.

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Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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Acknowledgements

This work was supported by a Grant-in-Aid for JSPS Fellows JP18J22537, JST ERATO grant number JPMJER1501 and JST ACT-X grant number JPMJAX190F. We thank M. J. Chabalko for discussions. We also thank K. Narumi, H. Ogata and T. Ikeuchi for help in the video production.

Author information

Authors and Affiliations

  1. Department of Electrical Engineering and Information Systems, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan

    Takuya Sasatani & Yoshihiro Kawahara

  2. Electrical Engineering and Computer Science Department, University of Michigan, Ann Arbor, MI, USA

    Alanson P. Sample

Authors
  1. Takuya Sasatani
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  2. Alanson P. Sample
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  3. Yoshihiro Kawahara
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Contributions

T.S., Y.K. and A.P.S. designed the research. T.S. proposed the initial concept, conceived the theory, implemented the system, performed the experiments/analysis and wrote the manuscript. All the authors reviewed and commented on the manuscript. Y.K. and A.P.S. provided the resources. Y.K. supervised the project.

Corresponding author

Correspondence to Takuya Sasatani.

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The authors declare no competing interests.

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Peer review information Nature Electronics thanks Jenshan Lin and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–11, Table 1 and Notes 1 and 2.

Supplementary Video 1

Overview of the room-scale resonator, including the resonator structure, mounted lumped capacitors, covered range and an animation of the oscillating current/magnetic field.

Supplementary Video 2

Demonstration of room-scale wireless power transfer in a living environment.

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Sasatani, T., Sample, A.P. & Kawahara, Y. Room-scale magnetoquasistatic wireless power transfer using a cavity-based multimode resonator. Nat Electron 4, 689–697 (2021). https://doi.org/10.1038/s41928-021-00636-3

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