In an experiment that electrical engineering researchers at Georgia Tech carried out, it was demonstrated that enough “ambient” electromagnetic energy from a television station that was half a kilometer away could be captured to power a temperature sensor.  The group uses ink-jet printers to make antennas on paper that can pick up frequencies between 15 and 60 GHz, and they imagine this technology being used in wearable bio-monitoring devices, RFID, food quality sensing, and self-powered wireless devices for smart homes.   MORE