Non-resonant, broad-band vibration-energy harvester based on self-assembled liquid bearing

This paper reports a non-resonant, broad-band electromagnetic vibration-energy harvester based on self-assembled liquid bearing made of ferrofluid. The liquid bearing suspends magnet array over a microfabricated multi-layer coil plate such that the energy harvester does not rely on any mechanical resonance, and can harvest vibration energy over a broad frequency range. The non-resonant energy harvester (20.7 × 12 × 4.5 mm3) produces μW level of power from 1 g acceleration even at 2 - 4 Hz, a frequency range that would be too low for a resonant energy harvester.