Imagine recharging your cell phone without plugging it in. Or powering your iPod while you walk around the house with it. Researchers at the Massachusetts Institute of Technology (MIT) have taken the first steps towards such wireless energy transfer by conceptualizing a way to transmit electricity over room-size distances. One day, they say, the technology could power whole households or even motor vehicles wirelessly.
The MIT team calls the concept a nonradiative electromagnetic field. It involves two simple ring-shaped devices made of copper. One, connected to a conventional power source, would generate magnetic fields similar to those that power electric motors. These fields would stretch outward a few meters and would only affect the receiving–or companion device–which would be outfitted with a second copper ring tuned to a specific frequency. Team leader Marin Soljačić says he began working on the concept because he wanted to find a better alternative to having to recharge his laptop computer and cell phone so frequently. He presented the team’s findings today at an American Institute of Physics forum in San Francisco, California.