Getting a charge out of wireless energy

16 years ago   •   1 min read

By Marcia Kadanoff

Now wouldn’t that be cool!

Of course, in an industry that is still struggling to get mobile content right after some 7 years or so, it’s unlikely we’ll be able to commercialize wireless energy anytime in the immediate future. Still it’s fun to think about what wireless energy sources would mean in terms of how we would use our various devices.

Researchers at MIT are developing technology that would enable users to charge up their cell phones and laptops without ever plugging into the wall. “We are very good at transmitting information wirelessly,” says MIT physics professor Marin Soljai but historically, it’s been much more difficult to transmit energy to power devices in the same way. Soljai and his colleagues have come up with a theoretical scheme that uses a small power “base station” plugged into an outlet to charge nearby devices. Wireless energy transfer is already in use in some types of RFID tags, but because of its limited range, this technique is not suited to powering up a roomful of gadgets. To achieve a mid-range wireless-energy, the plugged-in base station emits low-frequency electromagnetic radiation in the range of 4 to 10 megahertz. Electronic devices can be designed to resonate at the same frequency emitted by the power station, enabling them to absorb the energy when they come within a couple of meters of the station.

Soljai envisions placing power hubs on the ceiling of each room in the house so that a phone or laptop can be constantly charging from any location in a home.

Technology Review 15 Nov 2006

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