Improved beamforming using curved sparse 2D arrays in ultrasound

Area of Science:

• Ultrasound transducer array design
• Acoustic imaging systems
• Array signal processing

Background:

• Periodic sparse two-dimensional arrays are used in ultrasonic imaging.
• Grating lobes can degrade image quality in phased array systems.
• Curving array geometry is explored as a method to mitigate grating lobes.

Purpose of the Study:

• Investigate the effect of curving phase-steered sparse periodic 2D arrays.
• Relate array curvature to geometric properties and performance.
• Evaluate the impact of curvature on grating lobe suppression and image quality.

Main Methods:

• Simulated point spread functions for various curved array layouts.
• Analyzed array performance with different element counts and focal points.
• Used parameters typical for volumetric cardiac imaging (3 MHz, 48x48 grid).

Main Results:

• Curving arrays suppresses grating lobes along the curvature direction more than flat arrays.
• Reductions in peak sidelobe level up to 12dB were observed for critical steering directions.
• Beamwidth and integrated sidelobe ratio showed comparable performance to flat arrays.

Conclusions:

• Curving a sparse periodic array in one direction effectively suppresses grating lobes.
• This geometric modification enhances image quality in volumetric imaging systems.
• Array curvature offers a simple yet significant improvement without added system complexity.