Ultrasound transducer models for piezoelectric polymer films

Abstract

A method is presented for determining the piezoelectric constants and the frequency-dependent dielectric properties of the polymers from a five-step algorithm based on analysis of air-loaded broadband impedance measurements. It is shown how to account for the frequency-dependent lossy properties of these films in an equivalent impedance circuit model and a modified Mason's model. Comparisons between the models and actual film transducers show excellent broadband simulation of both electrical input impedance and ultrasonic pulse-echo performance.

Impedance spectroscopic studies of cement-based piezoelectric ceramic composites

“…This form assumes that the conduction term is dominated by the migration of charge carriers. This means that one should use a frequency-dependent resistor in parallel with a capacitor to account for the losses, as was done in the work of Brown and Carlson [12] for the static branch of their model. These highlight and discussion match the situation of cement-based piezoelectric ceramic composites well as the cement paste holds a considerable energy loss.…”

“…If a piezoelectric material with significant losses, this model can not accurately represent the relationship. Other researchers [12,13] have tried to generalize the Van Dyke model by including resistive elements in parallel or in series with the other reactive parameters to solve this problem. It is one acceptable method to settle the problem with high losses by appending a resistor to static branch.…”

A KLM–circuit model of a multi-layer transducer for acoustic bladder volume measurements

“…The Simplex method was again used to minimize the LMSE between the measured and calculated time waveforms. It must be noted that the electrical and the mechanical losses of the PVDF-layer are frequency dependent [8]. As these losses were difficult to determine correctly, all PVDF parameters were assumed to be frequency independent.…”

Contribution au développement d'un capteur ultrasonique pour mesurer l'épaisseur de la glace /

“…Ce modèle, appelé modèle de Van Dyke (voir figure III-8), est généralement recommandé par la norme internationale IEEE [Brown et Carlson, 1989]. [Ohigashi, 1988] et [Yagi et Tatemoto, 1978].…”