Effect of saw-cut depth on characteristics of array transducer

The authors suggest that saw-cut depth affects the electroacoustic conversion characteristics of an array transducer. To investigate this, they made several samples and measured the impedance of the sawed part of the backing. The results indicate that this impedance is less than that of the solid backing because the acoustic velocity of the sawed part is decreased. Assuming that the sawed part acts as a pseudolayer between the PZT (lead zinc titanate) elements and backing, the authors calculated transducer conversion characteristics by computer simulation. On the basis of the simulation, they built transducers and measured their characteristics. Excellent agreement between the simulation and experiment supports the pseudolayer theory. It is concluded that by making good use of the saw-cut-depth effect, high-efficiency broad-bandwidth transducers can be made