Feasibility and potential application of power scavenging from environmental RF signals

In this paper, we presented measurement results of electrical field intensity from broadcasting and mobile communication systems in order to show the feasibility of energy harvesting from RF signals. Experimental results show that RF signal from mobile phone systems are observed at various locations but the strength varies frequently depending on the mobile phone traffic. Radiowave from broadcasting tower, on the other hand, was very stable temporally but the strength depends on the distance from the broadcasting tower. From the measurement results, we believe it is possible to scavenge electric energy from RF signals using a carefully tuned rectifier with high gain directional antenna. However, it is also necessary to compensate instability of energy supply by tricks in the upper layers such as network protocols and application software.