Design of a novel PZT-ceramic-based piezocomposite for broadband array ultrasonic transducer with enhanced electromechanical coupling.

Enhancing the electromechanical properties of piezocomposite materials is crucial for the advancement of ultrasound transducers and medical imaging technology. To address the limited electromechanical coupling coefficient of traditional 2-2 piezocomposites utilized in phased array ultrasonic transducers, this work proposes a new 2-3 piezocomposite structure based on Pb(Zr1-xTix)O3 (PZT) ceramics. Both simulated and experimental results indicate that the designed 2-3 piezocomposite exhibits superior electromechanical coupling coefficient, with an electromechanical coupling coefficient (keff) of 0.643, exceeding the 2-2 piezocomposite (0.597) and matching the performance of 1-3 piezocomposites. This enhancement is attributed to the introduction of the longitudinal k33 vibration modes. Furthermore, a 3 MHz array transducer fabricated with the 2-3 piezocomposite achieves a -6 dB bandwidth of 105.4 % and an insertion loss of -21.57 dB. Those results not only outperform PZT-ceramic-based 2-2 array transducers but are also comparable to those of a single-crystal-based 2-2 counterpart. Additionally, this structure shows potential for extension to other piezoelectric ceramic and single-crystal systems. This design strategy offers a promising avenue for developing high-performance piezocomposites and high-resolution ultrasound transducers.