Inst. of Acoust., Nanjing Univ., Nanjing 210008, People's Republic of China
Analogic Corp., Peabody, MA 01960
Piezoelectric composite materials are increasingly used in medical and other ultrasonic transducers. In order to design composite transducers with desirable performance, especially in high-frequency range where polymer and ceramic structures are not much smaller than wavelength, a good understanding of dynamic behavior of the material is necessary. This work developed a dynamic model to investigate wave propagation along thickness direction and resonant behavior of the transducer. Relationships of thickness resonant frequencies as well as lateral periodic resonant frequencies with composite configuration and material (polymer and ceramic) properties were emphasized. Discussions on coupling coefficient k[sub t] of transducers as a function of volume fraction and aspect ratio of composite are presented. A series of composite transducers with varied parameters were fabricated and measured. Experimental results of k[sub t] and resonant frequencies are compared with the theory.