An Electrically Tunable Low Frequency Electromagnetic Energy Harvester

Abstract This paper reports the design, fabrication and experimental results of a low frequency electromagnetic energy harvester on FR4. The resonant frequency of the device is tuned electrically by using a generalized load (a capacitance in parallel with a resistance) instead of conventional resistive load. The device produces a maximum load power of 57 μW across 3310 Ω resistive load at 37.5 Hz of untuned resonant frequency under 0.1 g input acceleration. Later, the resonant frequency of the device is experimentally tuned up to 37 Hz successfully by changing the load capacitance from 0 to 10 μF. Though, this tuning comes with reduction in output power. It is observed that only 8.5% of the untuned maximum load power is obtained at the limit of the tuned range.