A device that recovers energy by converting microwave signals into electricity
Tuesday November 12, 2013, by Bernard Neumeister
Joining the ranks of devices designed to recover energy from ambient electromagnetic radiation is transformed into an electrical circuit by researchers at Duke University, a circuit that can be adapted to capture microwave energy from various sources, including including Wi-Fi, satellite or sound signals. Researchers say the device converts energy that would otherwise be lost to direct current with an efficiency similar to that of today's solar cells.
Duke University students Allen Hawkes and Alexander Katko, in collaboration with Duke's principal investigator and professor of electrical and computer engineering, Steven Cummer, constructed the device using five fiberglass and conductors of copper energy wired to a printed circuit board to form a five-cell metamaterial network. The team explains that the resulting electrical circuit is able to recover the microwaves and converts them into 7,3V electrical energy. They compare this to USB chargers for mobile devices that provide about 5 V of power.
“We were aiming for the highest energy efficiency we could achieve,” says Allen Hawkes. "We got around 6-10% energy efficiency, but with this design we were able to significantly improve the energy conversion to 37%, which is comparable to what is achieved with solar cells."
In addition to microwaves, the researchers say that the network of metamaterials could be adapted to recover power from a range of frequencies, as well as those of vibrations and sound waves.
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