Technique can 'harvest' energy in the air

ATLANTA, July 7 (UPI) -- U.S. researchers say energy transmitted by radio and television transmitters, cellphone networks and satellite systems can be captured and harnessed.

Scientists at the Georgia Institute of Technology say scavenging the ambient energy all around us could provide a new way to power networks of wireless sensors, microprocessors and communications chips.

"There is a large amount of electromagnetic energy all around us, but nobody has been able to tap into it," said Manos Tentzeris, a professor in the School of Electrical and Computer Engineering. "We are using an ultra-wideband antenna that lets us exploit a variety of signals in different frequency ranges, giving us greatly increased power-gathering capability."

Communications devices transmit energy in many different frequency ranges, or bands, that the researchers' scavenging devices can capture and convert from AC to DC and then store in capacitors and batteries, a Georgia Tech release said Thursday.

Experiments utilizing TV bands have already yielded power amounting to hundreds of microwatts, and multiband systems are expected to generate one milliwatt (one-thousandth of a watt) or more -- an amount of sufficient to operate many small electronic devices, including a variety of sensors and microprocessors, the researchers said.

The scientists say they have already successfully operated a temperature sensor using electromagnetic energy captured from a television station a third of a mile away.