E-WEHP: A Batteryless Embedded Sensor-Platform Wirelessly Powered From Ambient Digital-TV Signals

The use of digital television broadcasting standards has resulted in transmission of perpetually on wireless digital-TV signals over the air at wider bandwidths in ultrahigh-frequency bands for high-definition video and audio broadcasts to TV and smart phones. This paper presents a unique embedded wireless energy-harvesting prototype (E-WEHP) that exploits the unique makeup of ambient digital-TV signals, and scavenges wireless power from them at distance of over 6.3 km from the TV broadcast source. The harvested wireless power is successfully used to power and sustain a 16-bit embedded microcontroller for sensing and machine-to-machine applications without the use of batteries. The E-WEHP uses a miniaturized planar log-periodic antenna and RF-dc charge-pump circuit with maximum sensitivities of -14.6 and -18.86 dBm and an embedded firmware-based power management scheme to power microcontroller peripherals from different types of ambient digital-TV signals.