Ambient energy harvesting from 2-way talk-radio signals for “smart” meter and display applications

A ambient wireless energy harvesting prototype made of a compact antenna and an optimized RF-DC converter circuit is designed to convert the wireless signal emitted by a 2-way radio into usable DC power at which many low power electronics and displays used in sensors and smart meters could operate. The output DC power of -4.75dBm is achieved with 1 M-ohm load resistance at 13 cm away from the 2-way radio whose transmitting power is 2W. Measurements show electronics with operating voltage of 18 V as well as capacitive LCD display can be powered on using ambient RF signals eliminating the need for batteries.