MEASUREMENTS OF ACTIVE &PASSIVE TRANSDUCERS MATERIALS

Commercial FEA software packages, ANSYS and PZFlex, have been used frequently both in industry and in academic laboratories for transducer design and simulation of transducer performance. To result in an accurate simulation, a knowledge of the acoustic and elastic properties of the active piezoelectric materials as well as the passive materials in a transducer like backing, matching, lens, and polymer filler is necessary. Unfortunately these data are almost non-existent for frequencies higher than 10 MHz. Even at lower frequencies the information is still scanty. In this project, the acoustic and elastic properties of these materials will be measured with a method that has been used at this laboratory and at University of Vermont previously. Longitudinal and shear velocity and attenuation can be measured by rotating a specimen in the water path between two transducers. The elastic constants can then be calculated from these data. Measurements will not only be made on conventional materials but also on materials such as silicon nitride and silicon oxide which can be deposited in thin layers and may be useful as matching layers for VHF transducers[unreadable]