Theoretical analysis of a resistance adjusting type piezoelectric cylindrical transducer

A resistance adjusting type piezoelectric cylindrical transducer is studied in this work. The transducer's functional components are two radially polarized piezoelectric short tubes. One of them is utilized to actuate the transducer, while the other is used to adjust its electromechanical characteristics, such as resonance and anti-resonance frequencies as well as the corresponding electromechanical coupling factor, through changing a connecting resistance. Based on the plane stress assumption, the electromechanical characteristics of this transducer in radial vibration are studied, and the expressions of input electric impedance are derived analytically. The theoretical solution is validated by comparing the results with a special case in a previous work. Furthermore, numerical analysis is conducted to study the effects of resistance and electrode on the transducer's electromechanical characteristics. The results indicate that adjusting the resistance enables the transducer's multi-frequency characteristics, and furthermore, there exists a special matching resistance that results in the transducer's optimal electromechanical coupling factor. This study provides a theoretical guide for designing and optimizing the resistance adjusting type piezoelectric cylindrical transducer, which has a potential application in the underwater sound and ultrasonic fields, among others.