A novel air-coupled piezoelectric micromachined ultrasonic transducers based on parametric excitation method

This paper presents a novel PMUTs excitation method based on parametric excitation. An extra AC perturbation voltage at twice the frequency of the main excitation frequency was superimposed on the conventional sinusoidal excitation voltage. Finite element analysis and numerical simulation was conducted for an air-coupled bimorph PMUTs. The level of amplification was related to the phase difference between the perturbation & driving voltage and the quality factor of the structure. Compared with the conventional bimorph PMUTs, the transmission sensitivity of the PMUTs excited by parametric excitation method, can be improved by more than 200% around 1 MHz working frequency. In the end a verification experiment was conducted to verify the amplification ability of the parametric excitation method.