Esaote S.p.A., Italy Lorenzo Spicci and Marco Cati Multiphysics Simulation Story: Optimizing Ultrasound Piezo-disk Transducers Esaote S.p.A., Italy Lorenzo Spicci and Marco Cati

The Challenge Medical ultrasound imaging is vital for many diagnoses, providing doctors with detailed information A smaller, more cost-effective machine could make this technology more accessible for facilities Performance depends heavily on probes Probes, the units placed on the body, are designed for maximum bandwidth Bandwidth provides greater image quality and a higher bandwidth could mean less probes are necessary

The Solution Transducer design made up of piezo- composite material, hard rubber backing, four acoustic matching layers and a silicon rubber lens Studied beam focusing and steering to specify properties of silicon rubber lens Using COMSOL with KLM (Krimholtz, Leedom, Matthaei) method: Possible to determine values of acoustic impedance that give desired probe performance Able to calculate optimal thickness for four matching layers Model used to simulate the final far field pressure as well as the transducer’s directivity performance.

The Simulation First model material and its properties to determine effect on transducer performance Then study piezoelectric material and stimulate the electric impedance and far field pressure level to compare modeling to experimentation Finally test beam focusing and steering to specify properties of lens Top, COMSOL model showing how the silicon lens allows the ultrasound beam to be steered or directed. Bottom, experimental and model results are in good agreement confirming modeling technique.