A Nonlinear Pulse Shaping Method Using Resonant Piezoelectric MEMS Devices.

In this article, a methodology for increasing the displacement of the membrane in nonlinear transducers is presented. This methodology that relies on pulse shaping is based on the frequency modulation of the excitation signal which in turn results in an amplitude modulation of the displacement of the resonator. The benefits of pulse shaping include the increase of the displacement of the membrane of the resonator, the ability to leverage two mechanisms to dynamically tune the resonant frequency of the device and a relative control of the decay time of the resonator. These properties have been verified using simulations and experimental results. The experimental results are performed using two nonlinear resonators with a frequency of 3.9 and 7.9 kHz. With a constant amplitude of the excitation voltage, experimental results show that the use of pulse shaping allows a velocity increase of the membrane of a piezoelectric microelectromechanical systems (MEMS) resonator of up to 191% for a softening type resonator (STR), and 348% for a hardening type resonator (HTR). The frequency tuning mechanism allowed the operation of the STR and of the HTR over a bandwidth of 280 and 115 Hz, respectively, while providing higher velocity than with the non-optimized excitation signal. The resulting pulse shaping methodology can be applied to other nonlinear resonators as shown using simulation and experimental results. Therefore, this work should lead to an increase of the use of nonlinear resonators for various applications.