Scavenging ambient electromagnetic energy to power small electronic devices

Scavenging ambient electromagnetic energy to power small electronic devices: "As you sit there reading this story you're surrounded by electromagnetic energy transmitted from sources such as radio and television transmitters, mobile phone networks and satellite communications systems. Researchers from the Georgia Institute of Technology have created a device that is able to scavenge this ambient energy so it can be used to power small electronic devices such as networks of wireless sensors, microprocessors and communications chips."