An accurate equivalent circuit for the unloaded piezoelectric vibrator in the thickness mode

Abstract

An equivalent circuit model for the unloaded piezoelectric vibrator in the thickness mode is presented. The model contains two branches, the motional branch and the static branch, like the lossless resonator model, but the circuit elements are generalized by making each a complex constant. The mechanical, dielectric and piezoelectric losses associated with the vibrator are accounted for by the imaginary components of the circuit elements. The model produced impedance curves that closely matched the impedance calculated by using equations derived from vibration theory and the data measured for lead zirconate titanate and PVDF - TRFE co-polymer samples. The calculation of the circuit parameters from the complex elastic, dielectric and piezoelectric material constants is straightforward and the model accurately fits both the baseline dielectric behaviour and the piezoelectric resonance around and below the fundamental resonance. Conversely, when the complex circuit parameters are known, the complex material constants can be derived by straightforward calculations without any loss of information.

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Research Papers. An Approach to Design Broadband Air Backed Piezoelectric Sensor

“…There is a fundamental relationship between the properties of the transducer and the quality of the resulting image; a several techniques have been developed for modelling transducer behaviour and hence predicting the required system response. Many computer models that describe the behaviour of ultrasonic piezoelectric transducer are currently available (Yaacob et al, 2011;Sherrity et al, 1997;Toda et al, 2012). In this paper a simulation is applied using the developed computer model (Ali, 1999) to evaluate the discrete time response.…”

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