Electric vehicles may one day be able to recharge while driving down the highway, drawing wireless power directly from plates installed in the road that would make it possible to drive hundreds—if not thousands—of miles without having to plug in.

Image Credit: CU Boulder

The innovation is to use electric rather than magnetic fields. Although the capacitance between two plates separated by the air gap between a vehicle and the roadway is very small, real power can be transferred if the frequency is high enough. At megahertz-scale frequencies, the researchers were able to transfer more than a kilowatt.