SBIR-STTR Award

This SBIR program will address the modelling, fabrication, and testing of single crystal composite transducers. Comprised of single crystal relaxor-PT piezoelectrics, both single element and array configurations will be investigated for high performance medical ultrasonic imaging transducers. In collaboration with TRS Ceramics, Inc., single crystal relaxor PT piezoelectrics will be integrated into the transducer, providing ultra high electromechanical coupling (up to 92%), broad bandwidth, high sensitivity, and decreased impulse response for improved axial resolution. Using a one dimensional model, bandwidths of up to 130% have been realized. A direct comparison between an optimally designed single crystal relaxor PT composite transducer and an optimally designed PZT composite transducer will be made to demonstrate this performance enhancement. This Phase I research will provide a basis for further transducer optimization and cost effective manufacturing of an optimally matched broadband array in Phase II. A Phase I option for modelling, construction, and testing of an array element will enhance the development of the Phase II proposal.

Single crystal relaxor-PT piezoelectric materials exhibit ultrahigh longitudinal electromechanical coupling coefficient and variable dielectric constant. However, their relative lower thickness mode electromechanical coupling coefficients (compare with 1-3 piezoceramic / polymer composite) limit their applications in medical imaging . In order to overcome the limitation of the single crystal material, we propose incorporating the single crystal materials into a 1-3 composite structure. In this project, a new method to characterize the electromechanical properties of relaxor-PT single crystal materials is proposed. After measuring the complete electromechanical constants, the effective medium theory and dynamic model will be used to optimize the performance of 1-3 single crystal composites. One dimensional equivalent circuit model will be used to model the performance of 1-3 composite ultrasonic transducer. Various novel high sensitivity short pulse length ultrasonic transducer and transducer array will be developed for medical imaging applications. In addition to the scientific issues related 1-3 single crystal composite, the techniques for developing large size single crystal materials and for the fabrication of 1-3 single crystal composite and composite ultrasonic transducer will be developed to commercialize the 1-3 single crystal composites and composite transducers.