The speaker presents a method for powering electronic devices from ambient radiofrequency (RF) signals. The proposed design of an RF energy harvester is made from a compact ferrite rod antenna together with the electronics necessary for converting the received signal into a form that can directly replace batteries. We show that our device can, in principal, power a wireless sensor node from ambient medium wave transmissions so long as the node is within 120 km of a 150-kW transmitter.
