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Published on: May 25, 2016
Element shape design of 2-D CMUT arrays for reducing grating lobes
Vito Bavaro1, Giosuè Caliano, Massimo Pappalardo
1Dipartimento di Ingegneria Elettronica, Università degli Studi Roma Tre, 00146 Roma, Italy. bavaro@uniroma3.it
Summary
Capacitive micromachined ultrasonic transducer (CMUT) arrays with novel element shapes reduce grating lobes and element count for high-quality 2-D volumetric ultrasonic imaging. This innovation enables smaller, more efficient transducer designs.
Area of Science:
- Biomedical Engineering
- Materials Science
- Acoustics
Background:
- High-quality ultrasonic volumetric imaging requires fully populated 2-D arrays, posing challenges due to element count and spacing requirements to avoid grating lobes (GLs).
- Capacitive micromachined ultrasonic transducer (CMUT) technology offers flexibility in element design, enabling exploration of novel array configurations.
Purpose of the Study:
- To propose and analyze a new CMUT element shape for designing fully populated 2-D arrays with a reduced element count for volumetric imaging.
- To demonstrate the effectiveness of the proposed element shape in minimizing grating lobes and improving beam characteristics.
Main Methods:
- Simulations were used to evaluate the performance of 2-D CMUT arrays with a novel, spatially interpenetrating element shape.
- Arrays were designed with element pitches larger than lambda (up to 3lambda) for rectilinear scanning and compared to standard squared element designs.
- Performance was assessed based on grating lobe levels, element count reduction, and signal-to-noise ratio (SNR) improvements.
Main Results:
- The proposed element geometry significantly reduces grating lobes in arrays with pitches larger than lambda (up to 3lambda) for rectilinear scanning compared to standard designs.
- This novel design reduces the number of elements by up to a factor of 9 and increases element size, enhancing SNR.
- For beam steering up to +/-15 degrees, element count can be reduced by a factor of 4 with a pitch equal to lambda.
Conclusions:
- The proposed spatially interpenetrating CMUT element shape is effective in designing high-performance, fully populated 2-D arrays for volumetric ultrasonic imaging.
- This approach overcomes limitations of traditional designs, enabling reduced element counts, larger element sizes, and improved SNR.
- The technology facilitates the development of more compact and efficient ultrasonic transducer systems for real-time applications.
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