LAUSR

Self-powered wireless sensor networks based on autonomous wireless sensor nodes have been increasingly attractive due to the outstanding merits of maintenance-free and self-sustainability. In spite of the explosive growth of the wireless sensor network techniques, the corresponding power supply methods with miniaturized, low-cost, flexible, reliable, and efficient designs are still limited. In this paper, a novel magnetic energy harvester based on nonlinear resonance is presented, which has been verified to be capable of scavenging energy from the power-frequency (50 or 60 Hz) magnetic field distributed around the transmission line. We have theoretically and experimentally demonstrated the greatly enhanced harvesting properties in both power density and enlarged bandwidth, which provides great robustness to frequency fluctuations of magnetic field. A prototype of this brand new design is fabricated and tested. Experimental results show that the prototype is capable of harvesting a power as high as 13.5 mW at merely 2.4 Oe (RMS) power-frequency AC magnetic field. The high power density (0.5625 mW/cm3 at 2.4 Oe) and the wide working bandwidth (2.6 Hz) promise its application prospects as a sufficient and reliable power supply for sensors in the smart grid.