Improving the characteristics of a transducer using multiple piezoelectric layers.

A type of transducer composed of several active piezoelectric layers is described. These layers are independently stimulated electrically to achieve performance, in terms of sensitivity and bandwidth, not available in conventional, single active layer designs. A straightforward modeling technique is employed for predicting the performance of these transducers and for determining the optimal excitation characteristics. The technique is initially developed for transmission, but its extension to reception and pulse-echo conditions is discussed. A selection of experimental results demonstrates the feasibility of the technique.