Degree Type

Dissertation

Date of Award

1988

Degree Name

Doctor of Philosophy

Department

Electrical and Computer Engineering

First Advisor

David L. Carlson

Abstract

The frequency-dependent lossy properties of piezoelectric polymer films prohibit the direct application of classical electromechanical circuit models. As a result, techniques have been unavailable for accurate simulation of piezo film ultrasound transducer performance;The first part of this work describes a method for determining the piezoelectric constants and the frequency-dependent dielectric properties for the polymers, from analysis of air-loaded broadband impedance measurements. It is then shown how to account for the frequency-dependent lossy properties of these films in a simple impedance circuit model and a modified Mason's model. Comparisons between the models and actual film transducers show excellent broadband simulation of both electrical input impedance and ultrasonic pulse-echo performance;In the second part of this work, the modified Mason's models were incorporated into an interactive design/simulation computer program. The simulation program provides an investigator with the means for performing 180 different quantitative tests of a prototype design, using any tuning or matching scheme;In the third part of this work, submersible P(VF[subscript]2-VF[subscript]3) ultrasound transducer probes were constructed and tests revealed excellent broadband ultrasonic performance. Comparisons between actual and predicted pulse-echo ultrasonic waveforms confirmed the accuracy and reliability of the derived modified Mason's models and simulation techniques.

DOI

https://doi.org/10.31274/rtd-180813-11149

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Lewis Frederick Brown

Language

en

Proquest ID

AAI8825903

File Format

application/pdf

File Size

382 pages

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