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DEVELOPMENT OF NOVEL 1-3 PIEZOCOMPOSITES FOR LOW-CROSSTALK HIGH FREQUENCY ULTRASOUND ARRAY TRANSDUCERS
by
Hao-Chung Yang
A Dissertation Presented to the
FACULTY OF THE USC GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(MATERIALS SCIENCE)
August 2012
Copyright 2012 Hao-Chung Yang
Object Description
| Title | Development of novel 1-3 piezocomposites for low-crosstalk high frequency ultrasound array transducers |
| Author | Yang, Hao-Chung |
| Author email | yangh@usc.edu;Yanghaochung@gmail.com |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Materials Science |
| School | Viterbi School of Engineering |
| Date defended/completed | 2012-05-24 |
| Date submitted | 2012-07-30 |
| Date approved | 2012-07-30 |
| Restricted until | 2012-07-30 |
| Date published | 2012-07-30 |
| Advisor (committee member) |
Nutt, Steve Goo, Edward Shung, K. Kirk Yen, Jesse |
| Abstract | The goal of this research was to develop a novel diced 1-3 piezocomposite geometry to reduce pulse-echo ring down and acoustic cross-talk between high-frequency ultrasonic array elements. PZT-5H based 1-3 composites (10 and 15 MHz) of different pillar geometries (square (SQ), 45° triangle (TR), and pseudo-random (PR)) were fabricated and then made into single element ultrasound transducers. The measured pulse-echo waveforms and their envelopes indicate that the PR composites had the shortest -20 dB pulse length and highest sensitivity among the composites evaluated. Using these composites, 15 MHz array sub-apertures (0.95 λ pitch) were fabricated to assess the acoustic cross-talk between array elements. The combined electrical and acoustical cross-talk between the nearest array elements of the PR array sub-apertures (-31.8 dB @ 15 MHz) was 6.5 dB and 2.2 dB lower than that of the SQ and the TR array sub-apertures, respectively. To further reduce inter-element cross-talk of kerfless annular array transducers, utilizing the piezocomposites with the PR pillar geometry, we fabricated high-frequency annular arrays. Each annular array was designed to have six equal-area elements and a center frequency of 40 MHz. The average center frequency estimated from the measured pulse-echo responses of array elements was 38.7 MHz and the −6 dB bandwidth was 51%. The average insertion loss recorded was 23.1 dB, and the maximum combined crosstalk between the adjacent elements was less than −31 dB. These results demonstrate that the 1-3 piezocomposite with the pseudo-random pillars may be a better choice for fabricating enhanced high frequency linear array ultrasound transducers; especially when mechanical dicing is used. |
| Keyword | piezocomposites; ultrasound; transducers; pseudo-random; crosstalk |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m |
| Rights | Yang, Hao-Chung |
| Access conditions | The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the author, as the original true and official version of the work, but does not grant the reader permission to use the work if the desired use is covered by copyright. It is the author, as rights holder, who must provide use permission if such use is covered by copyright. The original signature page accompanying the original submission of the work to the USC Libraries is retained by the USC Libraries and a copy of it may be obtained by authorized requesters contacting the repository e-mail address given. |
| Repository name | University of Southern California Digital Library |
| Repository address | USC Digital Library, University of Southern California, University Park Campus MC 7002, 106 University Village, Los Angeles, California 90089-7002, USA |
| Repository email | cisadmin@usc.edu |
| Archival file | uscthesesreloadpub_Volume4/etd-YangHaoChu-1066.pdf |
Description
| Title | Page 1 |
| Full text | DEVELOPMENT OF NOVEL 1-3 PIEZOCOMPOSITES FOR LOW-CROSSTALK HIGH FREQUENCY ULTRASOUND ARRAY TRANSDUCERS by Hao-Chung Yang A Dissertation Presented to the FACULTY OF THE USC GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (MATERIALS SCIENCE) August 2012 Copyright 2012 Hao-Chung Yang |
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