| Popis: |
In this study, the characteristics of an ultrasonic beam radiated by a variable-line-focus-beam transducer were numerically calculated by finite-difference time domain (FDTD) method and liquid-elastic wave reflection theory. The interference ripple caused by a leaky surface acoustic wave (SAW) was observed in the lens width vs received intensity curve. Reasonable results, the true-circle-arc-lens in the literature, were obtained. As in the conventional V(z) curve, the ripple changed according to the attenuation parameter α and the leaky SAW velocity. Unlike for the conventional true-circle-arc-lens, the ripples caused by the leaky SAWs are observed at both sides of the focal point. |
