Characterization of piezoceramic rectangular parallelepipeds by means of atwo-dimensional model

The characterization of piezoelectric resonators is a field of intense scie ntific work; moreover, clear and accepted IEEE and TEC Standards have been published, showing the concepts and routes to perform the complete characte rization of piezoelectric resonators. All of the accepted procedures define some resonator geometries, each of them related with a set of parameters, that can be obtained following resonance measurements at the corresponding resonance frequencies. The basis of the standards is the existence, for eac h geometry, of well-defined modes that have been analytically solved. The d evelopment of multi-dimensional models of the waves' propagation in piezoce ramic materials opens the possibility of characterizing piezoelectric reson ators with geometries different from those recommended in the standards. In this paper, a two-dimensional model, which takes into account the mechanic al and dielectric losses, has been used to characterize piezoceramics with the shape of a regular parallelepiped. A set of elastic, dielectric, and pi ezoelectric parameters, which are useful for piezoelectric transducer desig n, can be obtained. For a given sample, the measured input electrical imped ance is used to obtain the parameters by means of a fitting process with th e corresponding model output. The results obtained with low and high loss m aterials show that the parameters found have Values similar to those obtain ed following the procedures and geometries recommended by the standards. Th is procedure permits the characterization of materials when the manufacturi ng procedure does not allow the fabrication of the shapes recommended by th e standards, making it a useful tool for transducer manufacturers and mater ial scientists.