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Cut the cord: MIT demonstrates wireless power transfer

By Layer 8 on Thu, 06/07/07 - 5:01pm.

Power wires are dead, long live power cords. A team from the Massachusetts Institute of Technology has experimentally shown how everything from iPods to laptops could be wirelessly recharged by using a carefully designed magnetic field to deliver power to such devices from a range of 10 to 15 feet.

Details about WiTricity, or wireless electricity, are reported today in Science Express. Various methods of transmitting power wirelessly have been known for centuries. Perhaps the best known example is electromagnetic radiation, such as radio waves.

While such radiation is excellent for wireless transmission of information, it is not feasible to use it for power transmission. Since radiation spreads in all directions, a vast majority of power would end up being wasted into free space. One can envision using directed electromagnetic radiation, such as lasers, but this is not very practical and can even be dangerous. It requires an uninterrupted line of sight between the source and the device, as well as a sophisticated tracking mechanism when the device is mobile,MIT said in a statement.

WiTricity is rooted in such well-known laws of physics that it makes one wonder why no one thought of it before. "In the past, there was no great demand for such a system, so people did not have a strong motivation to look into it," points out MIT professor John Joannopoulos. "Over the past several years, portable electronic devices, such as laptops, cell phones, iPods and even household robots have become widespread, all of which require batteries that need to be recharged often, "he said.

The researcher said MIT would handle licensing of the technology should it be used in a consumer service or product in the future.