Optimization of silicon longitudinal mode ultrasonic actuators, with application to surgery

An analytical electromechanical model of a silicon/PZT laminate longitudinal mode resonant transducer is presented. The excellent agreement between the measured and calculated impedances based on the analytical model proves the validity of the model. For a typical device used for ultrasonic surgery, the experimental data shows a maximum value of 34 for the product of the quality factor and the effective electromechanical coupling. This figure of merit product, an indication of the power output capacity of a transducer, is two to three times higher than that of the currently used metal-based transducers. Force required to ultrasonically cut tissue with the optimized transducer is presented.