Sandwich structured electrostatic/electrets parallel-plate power generator for low acceleration and low frequency vibration energy harvesting

This paper reports an improved design, fabrication method, testing and analysis of electrostatic/electrets parallel-plate power generator driven by sinusoidal vibration sources having low acceleration (<;0.05 g) and low frequency vibration (<;50Hz). An electrostatic/electrets power generator is designed with sandwich structure containing two capacitive systems. Apart from the virtue of harvesting small vibration energy source, it also generates higher power output than conventional two-layer parallel-plate structure by reducing damping effect caused by inherent electrostatic force F_e. A localized corona charging method, using charging mask, for ion implantation into electrets has significantly reduced the fast charge decaying problem in micro scale patterned electrets plates and simplified the charging procedure.