Portland, Ore. -- A technology shown at the Consumer Electronics Show that uses wireless energy transfer to power small devices or recharge batteries could be headed to market this year.
At Philips Electronics N.V.'s CES booth, Powercast LLC (Ligonier, Pa.) showed its Powercaster energy beacon and several Powerharvester modules powering sensors directly and recharging the batteries in remote controls, iPods and cell phones. Philips plans to announce its first consumer device using paired Powercasters and Powerharvester modules in 2007. Medical implants will also begin using wireless energy transfers in 2007, Powercast said.
"We have a technology that's here today, with FCC approval, that sends RF signals through the air to power very low- power devices directly or to recharge battery-powered devices," said Powercast vice president Keith Kressin. "Our wireless systems can recharge batteries in any consumer device smaller than a cell phone, from up to a meter away."
The Powercaster transmits RF energy to companion Powerharvester receiver modules that measure about half the size of a AAA battery. In beta tests of a wireless sensor network at the Pittsburgh Zoo, a Powerharvester module was retrofitted to the battery compartment of a wireless sensor made by Intellisensor (Pittsburgh), extending the sensor's battery life from five days to 320 and counting, according to Kressin.
Powercast's technology uses the 900-MHz industrial, scientific and medical band. It can scale to 1.8, 2.4 or 5.8 GHz, but energy transfer is said to be typically more efficient at lower frequencies.
"At CES, we demonstrated an omnidirectional energy beacon using a dipole antenna emanating from a lamp," said Kressin. "We supplied milliwatts of power to any number of devices within about a 1-meter radius around the lamp. You can also use a directional antenna to send a more concentrated beam, but you have to be wary of health issues."
In the upcoming Philips implementation, an omnidirectional power beacon will recharge devices within about a 1-meter range. The zoo beta test, by contrast, used a directional antenna so that the power beacon could be located 30 feet away from the sensor it was powering.
The narrow-beam transmitting antenna for the zoo retrofit was a patch antenna--a narrowband antenna fabricated by etching the element pattern in metal traces on a pc board.
Protected by a portfolio of 100 patents, Powercast hopes to license its wireless energy methodology to companies that sell battery-powered devices.
"We are an ingredient supplier," said Kressin. "Our model is to put Powercasters in lamps, on the underside of your cabinets, in drawers or even inside your safe. Then you put your devices anywhere nearby, and they stay charged.
"You can forget their orientation, forget the use of coils; just watch the LED get brighter the closer you place your device to the Powercaster."
Powercast's technology for wireless energy transfer is unrelated to the Massachusetts Institute of Technology's recent development of wireless power beacons. Instead of standard, 900-MHz transmitters and receivers, the MIT energy transfer technology uses a proprietary beacon and resonant-antenna setup.