Revisiting multi-node wireless magnetic resonant coupling charging in sensor networks

Wireless sensor networks have been widely studied and find applications in military as well as civil contexts. Due to limited lifetime of sensor batteries, varied approaches to extend the lifetime are intensively investigated. Recently, wireless energy charging technologies, especially the magnetic resonant coupling, have been resorted to offer sufficient energy supply for individual sensors. Seeking even higher efficiency of these wireless charging is desirable. This paper revisits the multi-node charging of the magnetic resonant coupling technology, which has higher charging efficiency and also longer charging distance when compared to other two wireless charging technologies. Our main contribution lies that we find that multi-node charging is not always beneficial and we also present an algorithm for calibrating positions of the mobile wireless charger under multi-sensor charging mode without a priori charging efficiency statistics.