Ultrasonic transducers are widely used in medical diagnosis and non-destructive testing applications based on ultrasound systems. As the needs for application areas increase, including clinical diagnosis that requires ultrasound imaging with higher definition and a larger imaging range, ultrasound transducers with higher spatial resolution and sensitivity are called for.
In recent decades, many researches have focused on piezoelectric components of ultrasonic transducers, aiming at improving the performance of the devices. One of the attempts is to develop novel piezoelectric composite materials with excellent performance. Piezoelectric composites combine the advantages of piezoelectric and polymer materials. Many scholars and our previous work have verified that traditional piezoelectric composites, such as 1-3, 2-2 and 1-3-2 composites, have advantages of low impedance and high electromechanical coupling factor, which are suitable for underwater ultrasonic applications. Recently, we have further improved the performance of piezoelectric composites by optimizing their microstructure and geometry. In the whole study on the optimization of piezoelectric composite materials, theoretical calculation, finite element simulation and experimental preparation were employed as the research methods, combined with artificial intelligence algorithm to optimize the structure and material parameters. We put forward a variety of functionally piezoelectric composite transducer design methods, which improved the bandwidth and sensitivity of piezoelectric ultrasonic transducers. It is verified that the proposed optimization method and the prepared transducer have great potential in ultrasonic imaging of biological tissues, nondestructive testing and application of acoustic tweezers.