Engineers develop printable antenna and power source

A new antenna that can be printed on paper or plastic may soon become a low-cost source of power for various devices with applications from aviation to medicine, merely by tapping electromagnetic energy from the surrounding air. Researchers at the Georgia Tech School of Electrical and Computer Engineering said the device can capture and harness energy from radio and television transmitters, cell phone networks and satellite communications systems. "By scavenging this ambient energy from the air around us, the technique could provide a new way to power networks of wireless sensors, microprocessors and communications chips," Georgia Tech said. The team’s scavenging devices can capture this energy, convert it from AC to DC, and then store it in capacitors and batteries. It said that the self-powered wireless sensors could be used for chemical, biological, heat and stress sensing for defense and industry; radio-frequency identification (RFID) tagging for manufacturing and shipping, and monitoring tasks in many fields including communications and power usage. Professor Manos Tentzeris and his team are using inkjet printers to combine sensors, antennas and energy-scavenging capabilities on paper or flexible polymers. Tentzeris, a faculty researcher in the Georgia Electronic Design Center at Georgia Tech, said there is a large amount of electromagnetic energy all around, but so far "nobody has been able to tap into it." He said they 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." Presently, the scavenging technology can take advantage presently of frequencies from FM radio to radar, a range spanning 100 megahertz (MHz) to 15 gigahertz (GHz) or higher. A energy-scavenging device could be used by itself or in tandem with other generating technologies. "For example, scavenged energy could assist a solar element to charge a battery during the day. At night, when solar cells don’t provide power, scavenged energy would continue to increase the battery charge or would prevent discharging," Georgia Tech said. Potentials By combining energy-scavenging technology with super-capacitors and cycled operation, the Georgia Tech team expects to power devices requiring above 50 milliwatts. "In this approach, energy builds up in a battery-like supercapacitor and is utilized when the required power level is reached," Georgia Tech said. For now, the researchers have 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 where a microprocessor-based microcontroller would be activated simply by holding it in the air. Future possible applications may include: • Airport security, tapping available ambient energy from radar and communications sources. • Energy savings: Self-powered wireless sensing devices placed throughout a home could provide continuous monitoring of temperature and humidity conditions, leading to highly significant savings on heating and air conditioning costs. • Structural integrity: Paper or polymer based sensors could be placed throughout various types of structures to monitor stress. • Food and perishable material storage and quality monitoring. • Wearable bio-monitoring devices: This emerging wireless technology could become widely used for autonomous observation of patient medical issues. — TJD, GMA News