A multi-piezoelectric structure: the stacked transducer

A new piezoelectric structure made of several ceramic plates stacked together is proposed. With such an arrangement a gain in sensitivity can be obtained via constructive addition of the different ceramic signals appropriately delayed. Conversely, a reduction of the pulse duration can be achieved with destructive interference. A general unidimensional model of a bi-stacked transducer based on the Mason model which takes into account multiple adaptive layers, losses, and the electrical network is derived. Experimental results obtained with a PZT/PVDF structure show very good agreement with this model. Another application is presented with a double-damped structure made of two piezo-composite ceramics. These new structures lead to a very-wide-band transducer suitable to medical imaging and NDT