Composite transducer with multiple piezoelectric matching layers

Trilaminate transducers have been constructed from fired 0-3 piezoelectric materials and nonvoided thick piezoelectric polymer as two matching layers on ceramic PbTiO₃. Based on the physical properties of the constituent materials, the equivalent circuit of this composite transducer has been established. The frequency response of transmitting, receiving, and voltage transition gain (VTG) for different layers and their hybrid connection was computed and compared with the experimental results. The frequency response of the composite transducer is considerably improved by changing the connecting modes between the layers. Different layers are shown to make different contributions to the frequency dependence of the sensitivity. The transducer impedence and sensitivity response can be adjusted depending on the application