Researchers harvest ambient electromagnetic energy to power small electronic devices
1 min read
Researchers at the Georgia Institute of Technology in the US have discovered a way to capture and harness energy transmitted by sources such as radio and television transmitters, mobile phone networks and satellite communications systems.
According to lead researcher Manos Tentzeris, a professor in the Georgia Tech School of Electrical and Computer Engineering, the device created is able to scavenge this ambient energy so that it can be used to power small electronic devices such as networks of wireless sensors, microprocessors and communications chips.
Tentzeris and his collaborators used inkjet printing technology to combine sensors, antennas and energy scavenging capabilities on paper or flexible polymers. The team's scavenging technology is able to take advantage of frequencies from FM radio to radar, in a range spanning 100Mhz to 15GHz or higher. The devices capture this energy, convert it from ac to dc, and then store it in capacitors and batteries.
"There is a large amount of electromagnetic energy all around us, but nobody has been able to tap into it," explained Tentzeris "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."
The researchers say they have already been able to generate hundreds of milliwatts by harnessing the energy from tv bands. They believe multi band systems could generate one milliwatt or more, which is enough to operate many small electronic devices. By combining energy scavenging technology with super capacitors and cycled operation, the Georgia Tech team expects to power devices requiring more than 50milliwatts.
The researchers have already successfully operated a temperature sensor using electromagnetic energy captured from a television station that was half a kilometer away. They are now preparing another demonstration in which a microprocessor based microcontroller would be activated simply by holding it in the air.
The researchers believe self powered, wireless paper based sensors will soon be widely available and at a low cost. They say the resulting proliferation of autonomous, inexpensive sensors could be used for applications that include self powered wireless sensing devices for the home, airport security, food quality monitoring and wearable bio monitoring devices.
