A NEW ALGORITHM TO CALCULATE THE TRANSIENT NEAR-FIELD OF ULTRASONIC PHASED-ARRAYS

A new algorithm valid for an accurate calculation of the near-field in the scanning plane of ultrasonic phased arrays is presented. Using the classical time domain impulse response approach, a simple analytical expression for the impulse response at points lying in the central plane of a narrow rectangular aperture is deduced. An expression for the array impulse response h(A) (xBAR, t) is then obtained by superposition. The proposed solution is useful for an efficient computation of transient and continuous wave (CW) pressure fields without requiring any far-field or paraxial approximations. Moreover, the convolution-impulse response approach applied to phased arrays in this work constitutes an important tool for the analysis of array fields. In this sense, some numerical examples are presented, in which the advantages of using the array impulse response in the field analysis are evidenced. Several aspects of array fields not currently described in literature are included in the examples.