High Q and low resonant frequency micro electret energy harvester for harvesting low amplitude harmonic of vibration

In this paper, we present the design, fabrication and testing of a micro electret power generator harvesting low frequency and low amplitude vibration sources by the aid of its high quality factor of the device. Conventional polymer, LDPE, is used as electret material in the power generator. Silicon inward S-springs with high spring constant ratios are proposed and incorporated into the device design. Resonant frequency of 97 Hz is achieved in the device testing with small volume of 0.26 cm
³
. High quality factor of 88.2 of the resonant system enables the power generator to output appreciable current when it harvests the low amplitude harmonic of vibration.