Modeling and Optimization of a PVDF Microresonator

MARTÍN A. ZALAZAR, FABIO A. GUARNIERI

2010-09-01/2011-03-01

Piezoeléctrica

Tecnol.sanit.y curativa-Otros

Purpose: Thin film bulk acoustic resonators allow a reduction in piezoelectric thickness layers, increasing its resonant frequency compared with quartz crystal microbalances. In this work, a thin film resonator macromodel was implemented and results were compared with a numerical model (FEM). Methodology: A macromodel based on the Mason model of acoustic transmission line was used. This model allows multiple piezoelectric layers (e.g. PVDF) and non piezoelectric layers (e.g. parylene). A 3D piezoelectric linear elastic solid was used for the PVDF (orthorhombic mm2) in the FEM model. A deposited polymer, parylene, was modeled as an isotropic linear elastic material. The electromechanical coupling factor was extracted from the harmonic analysis of the unloaded piezoelectric polymer. Results: The average relative deviation in the frequency shifts computed by the two models for a parylene deposition was lower than 0.28% and the resonance frequency improved from 1.10% to 0.01% using the extracted electromechanical coupling factor. Conclusions: These results motivate the application of the macromodel for modeling the parylene deposition on the PVDF resonator in the deposition range used. It was demonstrated the importance of parameters extraction from the FEM model.