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Improved RF Power Harvesting Circuit Design (ISR IP)

ISR intellectual property available to license

Inventors: Thomas Steven Salter, Jr., George Metze, Neil Goldsman

RF Wireless electronics play a crucial role in collecting and relaying information in modern society. System designers are constantly pushing the technology by reducing the system form factor and increasing the operational lifetime on a single battery charge. One of the fundamental challenges towards decreasing size and extending lifetime is the limited capacity of miniature battery technology. To overcome this challenge, the ability to harvest energy from the environment could greatly extend the operational life of portable electronics and reduce their size.

The environment is full of radiated emissions. Significant RF power levels can be detected both domestically and internationally due to cellular and ISM band emissions. By harvesting this radiated power, battery life could be extended and form factors could be reduced. The complexity lies in the efficient conversion from AC to DC and delivering this power to our system at the correct voltage.

Researchers at the University of Maryland in association with NSA have developed a novel circuit that has an excellent RF power harvesting efficiency. The circuit has been fabricated in a commercially available 130nm CMOS process and occupies an area of 300um by 600um. The circuit generated a 1V signal across a 70 kohm load from less than 66uW of input RF power at 2.2GHz. The operational RF frequency of the circuit can be re-tuned to frequencies in the ISM and cellular bands as necessary by the application. The RF to DC conversion efficiency was measured to be 22.6%, which is much higher compared to existing RF Power Harvesting designs and makes the recharge of portable wireless electronic devices off ambient RF energy sources feasible. A system using this circuit could operate indefinitely off of the RF energy in the environment due to cellular/television networks and wireless consumer electronics.

For more information
If you would like to license this intellectual property, have questions, would like to contact the inventors, or need more information, contact ISR External Relations Director Jeff Coriale at or 301.405.6604.

Find more ISR IP
You can go to our main IP search page to search by research category or faculty name. Or view the entire list of available IP on our complete IP listing page.

ISR-IP-Goldsman ISR-IP-batteries

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June 23, 2007

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For more information, contact ISR External Relations Director
Jeff Coriale at or 301.405.6604.

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