Study on focusing characteristics of curved phased array probe

Abstract

The focusing principle of curved phased array probe was investigated through experiment and acoustic simulation. Two sets of delay time, i.e. the linear and curved array mode, were applied to the curved phased array probe respectively, and the corresponding characteristics of ultrasound field were analyzed. Numerical results show that under the condition of linear array mode, the ultrasound of side elements could not effectively focus to the axial ultrasound beam due to the phase mismatching between elements. These energy dissipations could be weakened with the decrease of aperture size or the increase of nominal focal depth. Besides, the actual focal position disagreed with the nominal focal depth, but kept approaching to the curvature center of probe due to the superposition of electronic focusing in linear array mode and the natural focusing induced by the circular-arrayed elements. Correspondingly, the evolution of ultrasound pressure on the radii surface with the nominal focal depth was also influenced which resembled those for experimental results. These would provide referential significance for the practical engineering applications of curved phased array probe.