Resonant cavity mode enabled wireless power transfer

This letter proposes using the electromagnetic resonant modes of a hollow metallic structure to provide wireless power to small receivers contained anywhere inside. The coupling between a large chamber (used as a cavity resonator) and a small wire loop (used as a receiver) is studied. An analytic expression for the coupling coefficient between the fields in the cavity and a loop receiver is derived. This model is validated against simulation and experimental results. Finally, wireless power transfer is demonstrated at an efficiency of over 60% for large volumes in the structure, even though the receiver is a small 7.6 cm square shaped loop and the distance to the source probe is greater than 1 m. This technique for wireless power transfer has thus far been unexplored, and the results here serve as a starting point for resonant cavity mode wireless power systems with many receivers having arbitrary locations and orientations. VC 2014 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4904344]