Duke University has just demonstrated the use of low-frequency magnetic fields to conduct wireless power transfer, over distance.
Pratt School of Engineering researchers are using metamaterials to create what they are calling a superlens, that translates a magnetic field from a power coil onto an exact twin, located nearby. This creates an electric current in the receiving coil. The result is the ability to send power through the air at greater distances than the size of a receiver and transmitter, and with great efficiency.
The university has teamed up on the project with Toyota Research Institute N.A. The superlens walls of the design are etched with spiraling copper wire. The repetitive coils and the design for a metamaterial use magnetic fields so that the fields are transmitted and kept in a narrow cone — resulting in high power intensity.
Eventually, the technology will be used to charge mobile devices as they are transported, and the power cone will become more focused by integrating a tuning capability.
You can find more information on how the technology works and the demonstration in the Nature Scientific Report.