| Harvesting power from the environment is an attractive alternative to battery-operated systems, particularly for long-term, low-power sensing applications such as wireless sensor networks. Vibration energy harvesting, among other methods, has been pursued to realize robust and self-sustaining systems on both macro-and micro-scales in recent years. However, conventional vibration energy harvesters are designed as linear resonators with narrow operating bandwidths, rendering them impractical in real world environment.;This thesis introduces a novel device, named Smart Sand, which solves the problem of narrow operating bandwidth in piezoelectric vibration energy harvesters. Wide bandwidth operation is a substantial advantage and is achieved by specifically designing the Smart Sand to operate in off-resonance, utilizing nonlinear stretching for energy transduction. Detailed theory, modeling and fabrication of a prototype device are investigated with special emphasis on characterization of active piezoelectric material.;While preliminary, these results pave the way towards ubiquitous and truly integrated micro-scale wireless sensor nodes. Their broadband operation could enable the use of battery-less systems in numerous applications ranging from structural health monitoring to security and personal healthcare systems. |
