Evaluation of Piezoelectric Resonator Parameters Using an Artificial Intelligence Technique

Abstract

An estimation procedure based on genetic algorithms is described and applied to find the fundamental parameters of thickness extensional lossy piezoelectric resonators. The clamped capacitance, electromechanical coupling coefficient, nominal resonance frequency and mechanical loss tangent are obtained using this procedure from experimental electrical impedance data. The exact one-dimensional expression of the electrical impedance as a function of frequency, extended with a complex elastic constant, is taken as a reference for the computed impedance curves. The mean square error between measured and computed impedance values is the base of the cost function employed in the fitting procedure. The procedure has been applied to the evaluation of parameters in piezoelectric plates. Results for a lead metaniobate ceramic disk are presented showing a good fitting to the experimental reference curves and a good performance in the evolution of the global mean square error.

Keywords:

• Piezoelectric resonators
• parameter estimation
• genetic algorithms

Acknowledgements

Work supported by the Spanish Ministry of Science and Technology. R&D Project DPI2002-00441. A. Ruíz's doctoral stay in the CSIC is funded by an AECI grant.