Complete ultrasonic transducer characterization and its use for models and measurements

Transmitting and receiving properties of ultrasonic piezoelectric crystal transducers that directly affect the measured output voltage in an ultrasonic measurement system are described. These transducer properties are the transducer's electrical impedance and sensitivity, the transducer's radiation impedance, and the transducer's effective parameters (effective radius and focal length). It is shown that all these properties can be obtained with a series of calibration measurements, most of them purely electrical in nature. This series of measurements is described, including a newly developed method that makes the determination of the transducer sensitivity simpler than with previous methods. It is demonstrated that by combining these transducer properties with knowledge of the electrical properties of the pulser/receiver and cabling and the acoustic/elastic processes present in an ultrasonic measurement system, it is possible to accurately simulate the output voltage of the system.