Application of the finite element method to modelling transducer bars

Lithium niobate (LiNbO₃) bars are widely used in high frequency applications like ultrasonic imaging and non-destructive testing. However due to a strong material anisotropy, the modeling of such bar transducers, for the sake of optimisation, is quite difficult. This paper is focused on the two-dimensional modeling of LiNbO₃ bars using the finite element method with the help of the ATILA code. Mode dispersion curves are displayed for the (YZw)36° cut. For this cut bar the in-water far-field directivity patterns are shown for several frequencies with width to thickness ratio (W/T) equal to 3.59