二维超声阵列换能器声场的两种时域仿真模型比较

Comparison of two field simulation models of two-dimensional ultrasound transducer arrays in time domain

针对二维超声阵列换能器的声场仿真,以xMATRIX超声换能器结构为原型,设计仿真实验对分割阵元空间脉冲响应模型和离散点阵代表模型的计算精度、计算效率、影响参数和适用场合进行了分析比较。结果表明,分割阵元空间脉冲响应模型计算速度快,精度高,对阵元尺寸、阵元间距、聚焦深度及阵元高宽比例敏感,广泛应用于均匀介质中的声场仿真。离散点阵代表模型计算成本高,对阵元数目和阵元代表点数敏感,便于进行非均匀介质中任意形状换能器阵列的声场仿真。在相同阵列孔径和激励脉冲下,分割阵元空间脉冲响应模型的计算精度比离散点阵代表模型高6%左右,二维声压曲线和三维声场的计算速度分别比离散点阵代表模型快20倍和1000倍。

Simulation experiments were designed to compare the segmented-element spatial impulse response model and the discrete point-matrix model for acoustic field calculation of two-dimensional transducer array e.g. xMATRIX transducer. Computation ac- curacy, efficiency, influential parameters and suitable application of the two models were analyzed and compared. The experimental results demonstrated that the segmented-element spatial impulse response model is fast and accurate, and it is sensitive to element size, pitch, focus depth and the ratio between height and width of elements. The segmented-element spatial impulse response model is a popular tool to simulate ultrasonic filed in homogeneous medium. The discrete point-matrix model is computed costly when applying to two-dimensional transducer array. Its accuracy is inferior to the segmented-element spatial impulse response model. The discrete point-matrix model depends heavily on the number of elements and their represented points. However, it is convenient to simulate the filed of arbitrarily shaped ultrasound transducer array in inhomogeneous medium. With the same array aperture and excited impulse, accuracy of the segmented-element spatial impulse response model is 6% higher than that of the discrete point-matrix model. Never- theless, its computation cost of two-dimensional and three-dimensional beam distribution is 20 and 1000 times lower than that of the discrete point-matrix model respectively.