Kerf filling material: Suppressing crosstalk and enhancing imaging quality in ultrasonic arrays

Crosstalk, a detrimental phenomenon in ultrasonic arrays, compromises resolution, penetration depth, and diagnostic reliability. This study examines the impact of kerf filling materials on crosstalk suppression and imaging performance via integrated numerical simulations and experimental validation. Two fillers with contrasting acoustic properties were evaluated: rigid epoxy resin (Epo-Tek 301) and soft silicone rubber (RTV-664). RTV-664, exhibiting lower acoustic impedance and higher attenuation, demonstrated reduced mechanical coupling between adjacent elements. To validate this, a 128-element linear array was designed and fabricated, with its electrical, transceiver, and crosstalk characteristics systematically assessed through finite element simulations, phantom experiments, and "in vivo" imaging. Results indicate that RTV-664 reduced crosstalk in first- to third-order adjacent elements by an average of 33.4% across the 4-8 MHz bandwidth, aligning with simulated predictions. Imaging tests further confirmed that RTV-664-based arrays achieved broader bandwidth, enhanced field uniformity, and superior image quality, including improved resolution, penetration depth, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). These findings underscore the critical role of kerf filling materials selection in crosstalk mitigation, offering theoretical insights and experimental evidence for optimizing ultrasonic array design toward high-performance medical imaging.