The Design and Fabrication of Ultrasonic Transducers and Transducer Arrays.
Abstract
The rapidly growing field of ultrasound is placing great demands on the performance of ultrasonic transducers. Techniques have been developed and used to improve the design of both bulk wave transducers as well as narrow element transducer arrays for use in electronically scanned and focused acoustic imaging systems. Fundamental experiments have been carried out to verify the theories used to design arrays. In particular, piezoelectric strip resonators with rectangular cross section have been made and measured both in air, and when loaded by liquids and solids. The measurements are compared to theoretical results with good agreement. The performance of resonators with matching layers to the load are also examined. Iterative computer programs to optimize the parameters for the acoustic matching layer(s) and the electrical matching network of both bulk wave and array transducers have been developed and are described. By including the interactions between electrical and acoustic matching in our models, we have been able to significantly improve both the theoretical and measured performance of our transducers, compared to the previous state of the art. A 3.65 MHz center frequency bulk wave transducer, was constructed to verify the computer results. The impulse response was approximately 2 1/2 cycles long with a round trip insertion loss of 10.9 dB at the center frequency, and the 40 dB ringdown time was 1.5 (mu)sec when working into a water load. A 3.8 MHz center frequency array has also been made. In this case, the impulse response was even shorter (about 2 cycles) with an insertion loss of 9.5 dB, and a 40 dB ringdown time of about 1.5 (mu)sec.
- Publication:
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Ph.D. Thesis
- Pub Date:
- 1983
- Bibcode:
- 1983PhDT........92S
- Keywords:
-
- Physics: Acoustics