Effects of the Source’s Shape on Nonlinear Ultrasound Beams
phenomena are the source of many artefacts that deteriorate the ultrasonic imaging quality. One of the issues to improve the beam’s pattern deals with using a suitable source shape. In this paper we develop a numerical code to simulate the ultrasonic propagation into liquid media. The code is based on the spectral method and solves the parabolic wave equation. We studied Bessel, exponential and cosine sources. We showed that sidelobes and nearfield oscillations are related to the speed of the variation of the first derivative of the on source excitation around the midpoint of the circular source and to the continuity at the border point. So we can choose the source’s shape to reduce sidelobes and nearfield oscillations with a limited diffraction beam.
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