Resonant frequency characterization of MEMS based energy harvesters by harmonic sampling analysis method

• A new and accurate experimental method for determining resonant frequencies of MEMS.
• The method is based on harmonic distortion analysis of MEMS electrical voltage output.
• Development of electrostatic energy harvesters as test samples.
• Comparison with measurements carried out by DLTS system are presented.
• An uncertainty as low as one part in 103 is achievable with this technique.

This paper presents a new and accurate experimental method based on harmonic distortion analysis to determine the resonant frequency of MEMS devices to be used as energy scavengers or more generally in widespread MEMS-based applications. This technique uses the mechanical–electrical analogy of MEMS variable capacitor acting as a low-pass filter to give access to both resonant frequency and damping factor of the mechanical system through the determination of the filter parameters as the cut-off frequency. Resonant frequencies ranging from 0.8 kHz to 5 kHz of electrostatic actuated MEMS-based harvesters have been measured by this technique with an uncertainty as low as a few parts in 103 in a good agreement with measurements carried out by using Deep Level Transient Spectroscopy system.