Wideband MEMS electrostatic energy harvester with dual resonant structure

In this paper, we propose the design and test of a wideband MEMS electrostatic energy harvester with a dual resonant structure based on the out-of-the-plane gap closing scheme. It is fabricated using advanced MEMS technology, and the overall size is about 13 × 18 mm
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, and comparing to traditional devices with single resonant frequency, the proposed device with dual resonant structure can resonate at two frequencies, which could provide strong mechanical coupling between the two subsystems at low vibration amplitude. Therefore, this device can harvest a decent power output from vibration sources at a broad frequency range near its two resonant frequencies. During the test, continuous power output up to 1.06-3.24 pW can be achieved under external vibration amplitude of 9.8 m/s
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(~1g) at a frequency range from 141.6 Hz to 191.1 Hz, which means the bandwidth of the device is about 30% of the central frequency. In random vibration test, the device also shows a good performance, and provides a promising application for energy harvesting from the scenarios with random vibration sources.