Design of a bulk-lead zirconate titanate ultrasonic transducer array addressing specific excitation modes

Abstract

Conventional ultrasonic transducer arrays generally use simultaneous or delayed excitation methods to generate various types of wave fronts in ultrasonic testing. Such array excitation modes are relatively simple and unable to maximize the functions of the array elements or element apertures. Accordingly, this study developed a novel excitation ultrasonic transducer array with flexible excitation aperture. A minimum row-column-addressing planar array structure for ultrasonic transducers based on bulk lead zirconate titanate (PZT) was designed for industrial ultrasonic testing. In addition, a transducer structure design scheme and truth table for array addressing with excitation logic were provided. By performing an acoustic field simulation, this study analyzed the relationship between the longitudinal amplitude and resonant frequency of the array elements and the impedance distribution. The transducer was fabricated and packaged using a circuit board and bulk PZT array elements. Testing revealed that the resonant frequency of the array was 1.07 MHz, the effective electromechanical coupling coefficient was 0.40, and the fractional bandwidth of the pulse echo response and spectrum was 38.46%. Using an aluminum block, performance in single-element, row-, column-, and full-array excitation was tested, and echo curves were obtained for multiple apertures. Using a single-circuit module, the transducer realized flexible gating and excitation of the array elements. The research provided a new method for industrial ultrasonic transducer array design.