Study on the dual-excited full-wavelength piezoelectric ultrasonic transducer

A cascade structure of half-wavelength transducer is proposed for improving power capacity of the transducer, and a dual-excited full-wavelength piezoelectric ultrasonic transducer consisting of two half-wavelength transducers is especially studied. Based on one-dimensional theory, the resonance and the anti-resonance frequency equations of the transducer are derived. The validity of the theoretical analysis is verified by using FEM software. The effect of the locations and volumes of the two piezoelectric ceramic stacks on effective electromechanical coupling factor k_eff of the transducer is also discussed. The results show that k_eff drops with both ceramic stacks moved away from the displacement nodes of their respective half-wavelength transducers, and first increases and then decreases with the increase of the volumes of the ceramic stacks. This study is useful for designing and optimizing the dual-excited full-wavelength transducer.