Efficient numerical simulation of transducer outputs for acoustic microscopes

A semi-numerical simulation approach, the so-called SIRFEM is presented. This approach can be applied to efficiently predict transient output signals of ultrasonic imaging systems operating in pulse-echo mode. In particular, we concentrate on acoustic microscopes, which exploit ultrasound waves with center frequencies >10 MHz to visualize inner structures of solid specimens. While the ultrasound pulses between ultrasonic transducer and specimen surface are analytically modeled (spatial impulse response), we perform finite element simulations to describe wave propagation in the specimen. As the computed B-mode images for a plastic sample containing various inclusions (e.g., air) demonstrate, SIRFEM provides reliable transducer outputs. This implies that both, reflections at inner structures and multiple reflections between specimen surface and those structures are considered.