Spatial transfer functions of resonant piezoelectric plates

The transfer and line spread functions of piezoelectric transducer plates used typically in acoustic imaging systems are studied. In normal usage the transducer plate is regarded as a spatial linear system, and is bounded by air on one side and water on the other. In the transmitter case, a partially electroded transducer plate converts its electrode pattern into an acoustic output pattern. In the receiver case the transducer plate converts acoustic energy, incident from the water, into a voltage. In either case, the transfer function inherently determines the resolving ability when employed for imaging. Previous analysis and discussion has been addressed to the problem of the transfer function of a transmitter plate. One of our purposes is to derive the transfer function in the receiver case and compare it with results of the transmitter analysis. Our approach to the problem is to use the wave potential method along with the systematic matrix technique applicable to multilayer conditions. The transfer functions are derived and discussed for both resonant and nonresonant performance. The spatial impulse responses are then calculated and presented graphically.