Time and frequency domain modelling of the piezoelectric transducer
A new model for piezoelectric ultrasonic transducers is proposed. Using a systems engineering approach, the concept of feedback is used to explain secondary piezoelectric effects and to clearly describe electro-mechanical interaction. The model is derived from the fundamental piezoelectric equations and it embraces the relevant practical situations where the transducer is subject to arbitrary electrical and mechanical loading. The following main features are incorporated within the model. a - It is valid over a wide range of frequencies, b - It is applicable in both transmission and reception modes, c - It involves realisable elements which are readily simulated, and d - piezoelectric, pressure and voltage interactions are clearly related. The model has been verified extensively in computer simulations and water tank measurements of transducer profiles. Extremely close substantiation of the theoretical analyses was obtained, and the model is considered to offer significant advantages over existing transducer analogies.