Crosstalk optimization of 5 MHz linear array transducer based on PZT/epoxy piezoelectric composite

Abstract

Array ultrasonic transducers using electronic scanning method can obtain high frame rate and high-accuracy images compared with single-element transducers. However, for array transducers, crosstalk is a common problem and has bad influence on imaging quality. In this work, a 5 MHz linear array transducer with low crosstalk level is developed using PZT/epoxy piezoelectric composite. This PZT/epoxy composite has higher thickness electromechanical coupling coefficient (65.1%) and lower acoustic impedance (19.4 MRayls) compared with PZT ceramics. The influence of the width and depth of kerf on crosstalk is simulated by PZFlex software and the optimized kerf sizes are width 0.3 mm and depth 0.1 mm. The linear array transducer is fabricated according to the simulation results and the crosstalk level is measured. The experimental results are consistent with simulation and the transducer with this optimized kerf size has smaller crosstalk level (−24.1 dB). The central frequency and − 6 dB bandwidth of fabricated linear array transducer measured by impulse-echo response method are 4.82 MHz and 60.2% respectively. Compared with transducers made of PZT ceramic, this linear array transducer made of PZT/epoxy composite has wider bandwidth. The 5 MHz linear array transducer fabricated in this work has good acoustic performance and low crosstalk level and it is expected to obtain high-quality images in medical ultrasound imaging.