May 21, 2009: Engineeers from Powercast Corp. and CAP-XX Ltd., which which develops nanostructured supercapacitors have introduced a wireless energy-harvester reference design that creates a battery-free power source for wireless sensors commonly used in security, environmental and condition-monitoring systems.

In operation, the design creates a perpetual power supply for fixed or mobile wireless sensor nodes deployed throughout a building or local area, eliminating the need for batteries or wired power.

The module integrates a power receiving antenna, a Powercast Powerharvester to convert radio waves into low DC power, and a CAP-XX supercapacitor. The supercapacitor stores the harvested energy and provides the peak transmission power a wireless sensor needs to transmit data over wireless networks.

The Powercast RF Energy Harvesting Module, front and back closup of components. (Photos courtesy of CAP-XX)

This reference design uses the 915 MHz band, but can be adapted for other frequencies, or set to harvest environmental radio waves from TV, radio or mobile phone networks.

The companies presented a collaborative paper, “Harvesting RF Energy and Powering a Wireless Sensor Node Using a Supercapacitor,” on May 18 at the Darnell nanoPower Forum in San Jose, Calif.

The complete module, cncluding power receiving antenna. (Photos courtesy of CAP-XX)