脉冲持续时间对凹球面聚焦超声换能器焦点大小的影响
Effect of pulse duration on the focal spot size of concave spherical surface focused ultrasound transducers
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摘要: 为实现更好的超声治疗效果和对目标区域的精准定位, 研究了换能器的聚焦声场分布特性。通过对凹球面超声换能器聚焦声场的理论计算、仿真和实验验证, 分析了不同脉冲持续时间的脉冲信号和连续正弦波信号作为激励信号对换能器横向声场和纵向声场特性的影响。结果表明, 脉冲持续时间对于换能器横向声场的焦点尺寸基本没有影响, 但对其纵向声场的焦点尺寸影响显著, 随着脉冲持续时间的增加换能器纵向声场的焦点尺寸增加, 且逐渐与连续正弦波下的换能器焦点尺寸接近。Abstract: 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.