This article applies nonlinear regression method in characterizing a lossy piezoelectric material, i.e. PVDF (polyvinylidene fluoride), which has been widely used for ultrasonic transducer design. The characterization is based on the measurement of electrical impedance. A computer based data acquisition system is built to collect the data. The fitting process is then applied to the collected data. The best fit parameters are achieved at the selected frequency range, which is in good agreement between the modeled impedance curve and experimental data points at resonance region. The whole data collection and evaluation process can be easily and fast implemented within a few minutes. The design and simulation of piezoelectric materials based MEMS ultrasonic transducer is one of the motivations for developing this method. The evaluated piezoelectric material parameters will be imported to the later transducer modeling to improve the design accuracy of MEMS devices with a reduced design period.
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