MIT Researchers Work Toward Wireless Power

Researchers with the Massachusetts Institute of Technology (MIT) have come up with an idea that may enable devices like cell phones and MP3 players to be wirelessly charged, according to an article on the MIT Technology Review website.

Marin Soljacic, an MIT professor of physics, said that although it’s common to transfer information wirelessly, the concept of sending electricity through the air from an outlet to a device is less refined, according to the Technology Review. Though the idea is not new—it has been around for hundreds of years—success in wirelessly beaming power through the air has been less frequent.

Soljacic and MIT colleagues Aristeidis Karalis and John Joannopoulos have come up with a method that in principle should allow devices to be wirelessly charged from a few meters away from a power “base station” plugged into an outlet, the Technology Review reports. The three presented the idea this week at the American Institute of Physics’ Industrial Physics Forum in San Francisco, Calif., according to the Technology Review.

Some radio frequency identification (RFID) tags used today are wirelessly powered to some degree via “inductive coupling,” the Technology Review reports. This concept occurs when electric current travels through wires, producing a magnetic field, which in turn draws another current from wires that are close to it. This method, however, works only when the wires are very close to each other, the Technology Review reports.

To boost the range under which electricity can be transferred from an outlet to a device, the MIT researchers propose a setup in which a power base station would be inserted into an outlet and send out low-frequency electromagnetic radiation with a range between 4MHz and 10MHz, Soljacic said, according to the Technology Review. A specially designed receiver built into a device could then resonate at an identical frequency to the power base station, taking in the energy as a charge when within a few meters of each other, the Technology Review reports.

Freeman Dyson, an Institute for Advanced Study professor of physics, told the Technology Review, “It’s a nice idea, and I have no reason to believe that it won’t work.”

Soljacic said charging a device wirelessly under the new idea would likely take about double the time it would using an electrical outlet, as it would be roughly 50 percent as efficient as conventional charging via cords, according to the Technology Review. The professor envisions an environment in which power hubs could be installed on the ceilings of rooms so that devices within range could be constantly charging, the Technology Review reports.

Soljacic also said that based on his own person calculations, as well as the proven effects of low-frequency radio waves, he thought that regardless of the fact that electricity would be radiating through the air, the proposed system would be safe for people to be around, according to the Technology Review.

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