FEM-based parameter extraction of a PVDF resonator

M. ZALAZAR; F A GUARNIERI

2012-10-10/2013-05-16

Nano/Microtecnología

Tecnologia sanitaria y curativa-Varios

Purpose: Piezoelectric polymers are a good option to develop piezoelectric-based acoustic wave devices. The polyvinylidene fluoride (PVDF) and its copolymers are the polymers with the highest piezoelectric effect. In this work, the parameters of a PVDF disk resonator are obtained from experimental and 3D FEM model. Methodology: A 3D piezoelectric linear elastic solid was used for the PVDF (orthorhombic mm2) and a 3D elastic linear isotropic solid was used for the electrodes in the FEM model. The complex elastic, dielectric and piezoelectric properties obtained from literature experimental data were used to fulfill the FEM model. The values were adjusted to fit the simulated frequency response with the experimental one. The obtained values thus were used to characterize the PVDF disk. Results: The values corresponding to maximum absolute admittance and impedance were fm=8.25 MHz and fn=7.8 MHz respectively. The electromechanical coupling factor of the resonator was kt33=10.8% while the quality factor was Q=10.15. The figure of merit of the resonator was M=0.096. The experimental frequency response of the PVDF resonator with Cu electrodes was obtained. In this case fm=10.13 MHz and fn =9.69 MHz. Conclusions: A set of useful constants were obtained. The agreement of the extracted values with the datasheet of the material reveals a good accuracy for the developed procedure. It motivates the application of the FEM model for modeling the performance of the PVDF polymer as a thickness mode resonator.