Effect of pulse duration on the focal spot size of concave spherical surface focused ultrasound transducers

To enhance the efficacy of ultrasound treatment and ensure precise positioning of the target area, the focused sound field distribution characteristics of the transducer is studied. The acoustic field of a concave spherical focused transducer is theoretically analyzed and calculated. Simulations and experiments are conducted to verify the theoretical results. The study analyzes the different effects of pulse signals with different pulse durations and continuous sinusoidal signals as excitation signals on the transverse and longitudinal acoustic field characteristics of the transducer. The results show that the pulse duration has no obvious effect on the focal spot size of the transverse acoustic field of the transducer, but has a significant effect on its longitudinal acoustic field. As the pulse duration increases, the focus spot size of the longitudinal acoustic field of the transducer increases and gradually approaches that of the transducer with continuous sinusoidal excitation.