Practical Method for Evaluating the Element Sensitivity Variation of an Ultrasonic Annular Phased Array Transducer.

Area of Science:

• Ultrasound transducer technology
• Acoustic engineering
• Medical imaging physics

Background:

• Annular phased array transducers have unique geometric features (ring-shaped elements, concentric configuration) causing distinct behavior from linear arrays.
• Standard sensitivity assessment techniques for linear arrays yield significant errors when applied to annular arrays, particularly regarding element-to-element variance.
• Accurate element sensitivity evaluation is crucial for reliable performance of annular phased array transducers.

Purpose of the Study:

• To investigate and accurately evaluate the element-to-element sensitivity consistency in annular phased array transducers.
• To develop and validate a modified algorithm for sensitivity assessment that accounts for the unique geometry of annular array elements.
• To improve the reliability of measurements for annular phased array transducers in practical applications.

Main Methods:

• Developed a Long-Belt source assumption model using the Rayleigh integral to analytically characterize ring-shaped element responses.
• Validated the theoretical model through numerical simulations, confirming a linear correlation between response amplitude and element radial width.
• Proposed and applied a modified sensitivity evaluation algorithm using response voltage per unit width to normalize for geometric variations.

Main Results:

• The modified algorithm significantly reduced the maximum measured sensitivity variation from 25 dB to 6 dB for a 32-element annular array transducer.
• The results demonstrate the intrinsic sensitivity consistency of the transducer elements, overcoming geometric differences.
• The central element's unique geometry prevents its evaluation with the current method, requiring separate consideration.

Conclusions:

• The proposed algorithm provides a more accurate evaluation of sensitivity consistency for annular phased array transducers.
• Correcting for geometric variations is essential for reliable sensitivity assessment in these unique transducer types.
• This method enhances measurement reliability, contributing to improved performance and application of annular phased array transducers.