Experimental Results on Energy Harvesting by Using AM Radio Broadcasting

Energy harvesting is the process of collecting small amounts of energies and converts them into electric power. Since power consumption of digital device has decreased, the energy harvesting is a good approach. The Fukuoka Institute of Technology is located near two AM radio broadcasting stations. Thus, a considerable electric power can be obtained by the electromagnetic waves radiated from these two stations. In this paper, we implement a rectifying antenna (rectenna) that coverts the electromagnetic waves into DC electric power. This rectenna is located at the place approximately 50 meters away from one of the AM radio broadcasting stations and provides a maximum power of 2.39 [mW]. Regarding this rectenna as a DC voltage source, the internal resistance and the electromotive force are 510 [kΩ] and 71.4 [V], respectively.