提高阿基米德螺旋相控阵换能器焦点声压的仿真研究

针对阿基米德螺旋相控阵换能器焦点声压不足的问题,通过有限元仿真,分别讨论了换能器阵元形状和频率改变与声场的变化关系,从焦点声压、偏转范围、栅瓣水平、焦域大小等方面进行了研究。结果表明,相同频率下,扇形阵元阿基米德螺旋相控阵换能器的焦点声压比圆形阵元时的焦点声压提高了32.28%,偏转范围为20 mm×20 mm×40 mm;在扇形阵元形状的情况下,频率选择0.9~1.0 MHz,不仅能获得较高的焦点声压,同时还能保证改善聚焦性能。文章的仿真结果为阿基米德螺旋相控阵换能器提高焦点声压,满足深部组织消融治疗需要的高功率要求提供了有用的设计参考。

Simulation research on increasing the focus sound pressure of Archimedean spiral phased array transducer

Aiming at the problem of insufficient sound power at the focal point of the Archimedean spiral phased array transducer, the relationships of the array element shape and frequency with the change of the acoustic field are discussed by finite element simulation separately from the aspects of focal sound pressure, deflection range, grating lobe level, and focal region size. The results show that at the same frequency, the focal point pressure of the Archimedean spiral phased array transducer composed of sector-shaped array element increases by 32.28% compared with the circular array element, and the deflection range is 20 mm×20 mm×40 mm; moreover, at the selected frequency of 0.9- 1.0 MHz, the former phased array transducer can not only get a larger focal point pressure but also can guarantee the focusing quality. This article provides a useful design reference for increasing the focal point pressure of the Archimedean spiral phased array transducer and achieving its higher output power required in the deep tissue ablation.