Finite element modeling of the pulse-echo behavior of ultrasound transducers

A new method for the numerical computation of the pulse-echo behavior of ultrasound transducers is presented. In this numerical scheme, the given physical problem is split into two finite element models for which three subsequential computer runs are performed. In a first finite element model, the transducer with its fluid environment is set up and, in a second finite element mesh an obstacle reflecting the outgoing ultrasound wave is modelled. The wave propagation in the fluid area between the first and the second mesh is computed via Helmholtz integral. The reported numerical scheme is applicable to any type of piezoelectric transducer. In this paper, the pulse-echo voltages due to reflecting elastic obstacles with different geometries are presented for ultrasound antennas which are of practical interest in respect to medical imaging. The obtained simulation results are in good agreement with experimental data. The new method allows the precise computer simulation of complex piezoelectric transducers on a highend PC