微纳相控线阵超声换能器参数的理论分析*

微纳相控线阵超声换能器参数(阵元数目、阵元宽度及阵元间距)直接影响其横向声场分布,而其横向声场分布是能否实现高成像分辨率、大探测深度的决定性因素,也是制备换能器的主要依据。该文利用数值模拟研究微纳相控线阵超声换能器阵元参数对其横向声场中主瓣强度、-3 dB主瓣宽度、第一级旁瓣及栅瓣的影响。结果表明,主瓣强度随着阵元数目增加而增大,随阵元间距减小而增大,随着阵元宽度的增大呈现先增大后减小的趋势;-3 dB主瓣宽度随着阵元数目和阵元间距的增大而减小,随着阵元宽度的减小而减小;此外,减小阵元数目、减小阵元间距或增大阵元宽度均可以抑制旁瓣;栅瓣在阵元间距满足一定条件时可以完全消除。通过这些研究为微纳相控线阵超声换能器的优化设计与制备提供理论参考。

Theoretical analysis of parameters for micro-nano linear phased arrays ultrasonic transducer

The design parameters of micro-nano linear phased arrays ultrasonic transducer, i.e., the number, width and pitch of array elements, have a directly impact on the lateral sound field distribution. The lateral sound field distribution of the micro-nano transducer is the decisive factor for high resolution and great detection depth, and is also the main basis of the design of micro-nano transducer. The influences of the parameters of array elements on the -3 dB bandwidth and strength of the main lobe, the primary side lobe and grating lobe of lateral sound field distribution are studied by numerical simulation. The results show that the strength of the main lobe increases with the increase of the number of the array elements, increases with the decrease of the pitch, and as the width of the array elements increases, the trend increases first and then decreases. The -3 dB bandwidth of the main lobe decreases with the increase of the number and pitch of the array elements, and decreases with the decrease of the array element width. Then, decreasing the pitch and number of array elements or increasing the array element width can suppress the primary side lobe. Besides, the grating lobe can be completely eliminated when the pitch of array elements meets a certain condition. The study provides a reference for the design and preparation of micro-nano linear phased array ultrasonic transducer.