Numerical Study and Simulation of the Crosstalk Effects on the Electroacoustic Performance of Ultrasonic Transducer Arrays Utilized in Medical Imaging Applications

Ultrasonic probes utilized in medical imaging applications, such as mobile echography, typically consist of a number of ultrasonic transducers placed in a matrix (3D image) or as linear arrays (2D image). High-resolution medical images are required for more accurate and secure diagnosis. For this purpose, research works in this domain are mainly focusing on the optimization of the electroacoustic capabilities of the ultrasonic transducers arrays. One of the primary elements known to affect how well transducer arrays perform is the crosstalk phenomenon. In fact, it affects the ultrasonic arrays’ directivity and lowers the quality of the captured images. This study examines quantitatively how the backing absorber, filling material, and matching layers that make up the transducer arrays affect the crosstalk phenomenon. In this research work, a transducer array with 17 piezoelectric components composed of PZ27 is modeled utilizing 2D-Finite Element Method (FEM). Firstly, several filling materials with different loss factors are considered to demonstrate their impacts on the electroacoustic behavior of the studied arrays. Then, to a solution the impedance mismatch issue between the piezoelectric components and the propagation medium (human body/water), double matching layers SU8-Epoxy are proposed as a solution. Furthermore, different backing absorbers are proposed to reduce the crosstalk phenomenon. It is found that, a lossy filling material, characterized by a large loss factor (tan δ), reduces the parasitic modes between the array’s elements but it decreases its sensitivity. Consequently, a compromise must be done to get a suitable array sensibility and acceptable crosstalk reduction. The simulations also showed that the main cause of the crosstalk phenomenon is the front matching layers.