Inventor Nikola Tesla imagined the technology to transmit energy through thin air almost a century ago, but experimental attempts at the feat have so far resulted in cumbersome devices that only work over very small distances. But now, Duke University researchers have demonstrated the feasibility of wireless power transfer using low-frequency magnetic fields over distances much larger than the size of the transmitter and receiver.
The advance comes from a team of researchers in Duke's Pratt School of Engineering, who used metamaterials to create a "superlens" that focuses magnetic fields. The superlens translates the magnetic field emanating from one power coil onto its twin nearly a foot away, inducing an electric current in the receiving coil.
The experiment was the first time such a scheme has successfully sent power safely and efficiently through the air with an efficiency many times greater than what could be achieved with the same setup minus the superlens.