Analysis on the Resonance Frequency of a Radial Composite Piezoelectric Ceramic Ultrasonic Transducer with Step Metal Ring

A step-type radial composite piezoelectric ceramic ultrasonic transducer is presented and its radial vibration is analyzed. The transducer consists of a piezoelectric ceramic thin disk polarized in the thickness direction and a step-type metal thin circular ring, which are connected together in the radial direction. The radial vibration of a piezoelectric ceramic thin disk and a step-type metal thin circular ring is analyzed, and their radial electro-mechanical equivalent circuits are obtained, respectively. Based on the electro-mechanical equivalent circuits and using the continuous conditions of radial force and velocity at the interface, the electro-mechanical equivalent circuit of the radial composite transducer is given and its radial frequency equation is obtained. The relationship between the resonance frequency and the position of the step in the transducer is analyzed. Based on the frequency equations, some radial composite piezoelectric transducers are designed and made, and their resonance frequency and anti-resonance frequencies are measured. It is shown that the measured resonance and anti-resonance frequencies are in a good agreement with the theoretical results from the frequency equations. It is expected that this kind of radial composite piezoelectric transducer can be used in ultrasonic motors, piezoelectric actuators and underwater sound moonie and cymbal transducers.