At Massachusetts Institute of Technology (MIT), a team led by assistant
professor Marin Soljacic is developing a method to broadcast power to
devices to charge them, rather than depending on cords and cables.
Instead of irradiating the environment with electromagnetic waves, a
power transmitter would fill the space around it with a "non-radiative"
electromagnetic field. Only devices designed to "resonate" with the
field would pick up energy. Energy not picked up by a receiver would be
reabsorbed by the emitter.

Still in the simulation stage, these non-radiative wireless power
emitters would have limited range, and the range would be shorter for
smaller-size receivers. The team calculates that an object the size of
a laptop could be recharged within a few meters of the power source.
Placing one source in each room of a house could provide coverage
throughout. Wireless energy could find industrial applications powering
freely roaming robots within a factory pavilion or charging cell

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