Frequency Band Broadening of Piezoelectric Ultrasonic Transducer Using Multifrequency Impedance Network Coupling Method

This paper addresses the bandwidth problem of ultrasonic transducers, and a frequency band broadening technique based on multi-frequency impedance network coupling is proposed. Based on the extended BVD circuit model, three coupled circuits including one first-order and two second-order are designed. The inductor-capacitor value and series-parallel connection method are reasonably chosen for tuning to achieve multi-peak resonance to improve the operating bandwidth of the transducer. The results show that for each order increase of the LC circuit, the resonance peak will increase by one, and the bandwidth will be broadened accordingly. Finally, the bandwidth of the first-order coupling circuit is increased by 50.45% and the bandwidth of the second-order coupling circuit is increased by 88.29%.