Pub Date : 1997-10-05DOI: 10.1109/ULTSYM.1997.663295
S. Krishnan, J. D. Hamilton, Matthew O'Donnell
Harmonic imaging can improve contrast between contrast agents and tissue when imaging microvasculature. However, the factor limiting contrast enhancement is harmonic signals generated by the medium as the ultrasound signal propagates through it. Here, the authors have developed a method known as the Harmonic Cancellation System (HCS) to suppress this propagating second harmonic and improve contrast between contrast agents and the surrounding tissue for harmonic imaging. Simulations and experiments have shown that the level of second harmonic signals can be reduced by about 30 dB using HCS.
{"title":"Suppression of propagating second harmonic in non-linear imaging","authors":"S. Krishnan, J. D. Hamilton, Matthew O'Donnell","doi":"10.1109/ULTSYM.1997.663295","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663295","url":null,"abstract":"Harmonic imaging can improve contrast between contrast agents and tissue when imaging microvasculature. However, the factor limiting contrast enhancement is harmonic signals generated by the medium as the ultrasound signal propagates through it. Here, the authors have developed a method known as the Harmonic Cancellation System (HCS) to suppress this propagating second harmonic and improve contrast between contrast agents and the surrounding tissue for harmonic imaging. Simulations and experiments have shown that the level of second harmonic signals can be reduced by about 30 dB using HCS.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83659112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-05DOI: 10.1109/ULTSYM.1997.661852
J. Gorce, D. Friboulet, J. D’hooge, B. Bijnens, I. Magnin
The local spectral estimation from radio-frequency (RF) signals in medical echographic ultrasound images is not a trivial task due to the noisy nature of the data resulting from a stochastic and nonstationary process, Significant improvements may be obtained by proposing a spatial regularization scheme, smoothing the local spectral estimates while preserving the discontinuities. Based on AR models, the authors propose a 2D regularization scheme in a Bayesian framework. The a-priori knowledge is expressed by means of Markovian Random Fields (MRF) defined on the reflection coefficients. The use of nonquadratic functions allows to preserve discontinuities. First the authors applied their method on simulated data containing spatial discontinuities of spectral characteristics, which showed the efficiency of the regularization technique. Then the technique was used on cardiac RF data. This shows the improvements as well for Integrated Backscatter (IBS) images as for Mean Central Frequency (MCF) Images or whole spectral estimation.
{"title":"Regularized autoregressive models for a spectral estimation scheme dedicated to medical ultrasonic radio-frequency images","authors":"J. Gorce, D. Friboulet, J. D’hooge, B. Bijnens, I. Magnin","doi":"10.1109/ULTSYM.1997.661852","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661852","url":null,"abstract":"The local spectral estimation from radio-frequency (RF) signals in medical echographic ultrasound images is not a trivial task due to the noisy nature of the data resulting from a stochastic and nonstationary process, Significant improvements may be obtained by proposing a spatial regularization scheme, smoothing the local spectral estimates while preserving the discontinuities. Based on AR models, the authors propose a 2D regularization scheme in a Bayesian framework. The a-priori knowledge is expressed by means of Markovian Random Fields (MRF) defined on the reflection coefficients. The use of nonquadratic functions allows to preserve discontinuities. First the authors applied their method on simulated data containing spatial discontinuities of spectral characteristics, which showed the efficiency of the regularization technique. Then the technique was used on cardiac RF data. This shows the improvements as well for Integrated Backscatter (IBS) images as for Mean Central Frequency (MCF) Images or whole spectral estimation.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89950670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-05DOI: 10.1109/ULTSYM.1997.663033
S.E. Carter, D. Malocha
This paper introduces a new weighted stepped chirp code signal for direct sequence spread spectrum (DS/SS) communications systems. This code signal uses the truncated cosine series functions as the chip functions. This code signal is the result of discretizing a continuous wave (CW) chirp which results in enhanced performance versus a pseudo noise (PN) code and equivalent performance and easier implementation than a CW chirp. This code signal will be shown to have improved compression ratio (CR) and peak sidelobe level (PSL) versus a PN code with identical code length and chip length. It also will be shown to have a similar CR and PSL compared to a CW chirp with identical pulse length and frequency deviation. The code signal is implemented on surface acoustic wave (SAW) devices which will be used as the code generator at the transmitter and the correlator at the receiver. Experimental data is presented and compared to the predicted results.
{"title":"SAW device implementation of a new weighted stepped chirp code signal for direct sequence spread spectrum communications systems","authors":"S.E. Carter, D. Malocha","doi":"10.1109/ULTSYM.1997.663033","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663033","url":null,"abstract":"This paper introduces a new weighted stepped chirp code signal for direct sequence spread spectrum (DS/SS) communications systems. This code signal uses the truncated cosine series functions as the chip functions. This code signal is the result of discretizing a continuous wave (CW) chirp which results in enhanced performance versus a pseudo noise (PN) code and equivalent performance and easier implementation than a CW chirp. This code signal will be shown to have improved compression ratio (CR) and peak sidelobe level (PSL) versus a PN code with identical code length and chip length. It also will be shown to have a similar CR and PSL compared to a CW chirp with identical pulse length and frequency deviation. The code signal is implemented on surface acoustic wave (SAW) devices which will be used as the code generator at the transmitter and the correlator at the receiver. Experimental data is presented and compared to the predicted results.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90226311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-05DOI: 10.1109/ULTSYM.1997.662986
Yuxing Zhang, J. Gong, Xianwen Zhou, Yulan Wei, J. Cheeke
In this paper, two high-resolution spectrometer systems based on SAW Chirp-Z-Transform are reported. To achieve high frequency resolutions of 15 kHz (for unweighted compressor) and 20 kHz (for weighted compressor), two SAW RAC, with 68 /spl mu/s dispersion duration each, are cascaded as an expander to offer a long-duration chirp signal and another RAC also with 68 /spl mu/s dispersion is used as the compressor. Both systems are developed in the form of independent modules, and can be used as general-purpose spectrometer subsystems.
{"title":"High-resolution spectrometer systems based on SAW chirp filters","authors":"Yuxing Zhang, J. Gong, Xianwen Zhou, Yulan Wei, J. Cheeke","doi":"10.1109/ULTSYM.1997.662986","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.662986","url":null,"abstract":"In this paper, two high-resolution spectrometer systems based on SAW Chirp-Z-Transform are reported. To achieve high frequency resolutions of 15 kHz (for unweighted compressor) and 20 kHz (for weighted compressor), two SAW RAC, with 68 /spl mu/s dispersion duration each, are cascaded as an expander to offer a long-duration chirp signal and another RAC also with 68 /spl mu/s dispersion is used as the compressor. Both systems are developed in the form of independent modules, and can be used as general-purpose spectrometer subsystems.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90354282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-05DOI: 10.1109/ULTSYM.1997.661753
K. Imano, H. Inoue
The cycloid function voltage having no resonant component is applied to the piezo-ceramic planar and concave circular transducers to generate the monopole ultrasonic pulse. On-axis pressure characteristics of two kinds of transducer are observed using monopole ultrasonic pulse. As the experimental results, 1) the sound field of monopole ultrasonic pulse is consisted of direct wave and edge wave, and these are separated in time near the transducer, 2) the monopole ultrasonic pulse from a planar transducer becomes bipolar pulse in the large distance from the transducer and 3) in case of the concave transducer, the monopole ultrasonic pulse is gradually changed to the bipolar pulse around the focus, are clearly observed. These experimental results can be explained by the interference between direct wave and edge wave using monopole ultrasonic pulse. A possibilities of the diffraction effect which dominated at the focus of concave transducer is also suggested.
{"title":"A simple method for generating the monopole ultrasonic pulse and its sound field","authors":"K. Imano, H. Inoue","doi":"10.1109/ULTSYM.1997.661753","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661753","url":null,"abstract":"The cycloid function voltage having no resonant component is applied to the piezo-ceramic planar and concave circular transducers to generate the monopole ultrasonic pulse. On-axis pressure characteristics of two kinds of transducer are observed using monopole ultrasonic pulse. As the experimental results, 1) the sound field of monopole ultrasonic pulse is consisted of direct wave and edge wave, and these are separated in time near the transducer, 2) the monopole ultrasonic pulse from a planar transducer becomes bipolar pulse in the large distance from the transducer and 3) in case of the concave transducer, the monopole ultrasonic pulse is gradually changed to the bipolar pulse around the focus, are clearly observed. These experimental results can be explained by the interference between direct wave and edge wave using monopole ultrasonic pulse. A possibilities of the diffraction effect which dominated at the focus of concave transducer is also suggested.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84632698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-05DOI: 10.1109/ULTSYM.1997.663044
B. Zaitsev, V. Kunetsova, S. Joshi
This paper is concerned with the influence of a viscous liquid on the propagation of acoustic waves in thin plates of lithium niobate. The characteristics of the three lowest order wave modes that such a plate can support (zeroth order antisymmetric Lamb wave A/sub 0/, symmetric Lamb wave S/sub 6/, and quasi-shear-horizontal wave QSH/sub 6/) are investigated. It is assumed that the liquid is isotropic such that its viscous properties are described by two independent components of viscosity tensor /spl eta//sub 11/ and /spl eta//sub 44/. It is found that the attenuation of the waves depends primarily on the shear component of viscosity /spl eta//sub 44/. The influence of expansion component /spl eta//sub 11/ is negligible. The attenuation per unit length is proportional to (/spl eta//sub 44/)/sup 1/2 / and f/sup 1,3/, where f is the frequency of the wave. Under identical conditions, the lowest value of attenuation is for the S/sub 0/ mode, while the highest is for the A/sub 0/ mode. For example, for h//spl lambda/=0.025 (h=plate thickness, /spl lambda/=acoustic wavelength) and /spl eta//sub 44/=0.003 Ns/m/sup 2/, the attenuation in dB/cm at a frequency of 1 MHz for A/sub 0/, S/sub 0/ and QSH/sub 0/ modes is 13.5, 0.024, and 0.073, respectively. The above results indicate that the S/sub 0/ wave is most suitable for use in devices operating in contact with a viscous liquid. The results also show that by using the three different wave modes, one can develop a viscosity meter with a very wide measurable range of viscosity.
{"title":"Propagation of acoustic waves in plates bordered with viscous liquid","authors":"B. Zaitsev, V. Kunetsova, S. Joshi","doi":"10.1109/ULTSYM.1997.663044","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663044","url":null,"abstract":"This paper is concerned with the influence of a viscous liquid on the propagation of acoustic waves in thin plates of lithium niobate. The characteristics of the three lowest order wave modes that such a plate can support (zeroth order antisymmetric Lamb wave A/sub 0/, symmetric Lamb wave S/sub 6/, and quasi-shear-horizontal wave QSH/sub 6/) are investigated. It is assumed that the liquid is isotropic such that its viscous properties are described by two independent components of viscosity tensor /spl eta//sub 11/ and /spl eta//sub 44/. It is found that the attenuation of the waves depends primarily on the shear component of viscosity /spl eta//sub 44/. The influence of expansion component /spl eta//sub 11/ is negligible. The attenuation per unit length is proportional to (/spl eta//sub 44/)/sup 1/2 / and f/sup 1,3/, where f is the frequency of the wave. Under identical conditions, the lowest value of attenuation is for the S/sub 0/ mode, while the highest is for the A/sub 0/ mode. For example, for h//spl lambda/=0.025 (h=plate thickness, /spl lambda/=acoustic wavelength) and /spl eta//sub 44/=0.003 Ns/m/sup 2/, the attenuation in dB/cm at a frequency of 1 MHz for A/sub 0/, S/sub 0/ and QSH/sub 0/ modes is 13.5, 0.024, and 0.073, respectively. The above results indicate that the S/sub 0/ wave is most suitable for use in devices operating in contact with a viscous liquid. The results also show that by using the three different wave modes, one can develop a viscosity meter with a very wide measurable range of viscosity.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82138540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-05DOI: 10.1109/ULTSYM.1997.661783
E. Konofagou, S. Alam, J. Ophir, T. Krouskop
Two methods are discussed to increase the dynamic range and enhance the signal-to-noise ratio in elastography (SNR/sub e/). One method uses variable applied strains to expand the elastographic dynamic range by selecting the strain estimates with the highest SNR/sub e/ out of a multitude of strain estimates. The second one is a completely new estimator that estimates the strain by an iterative temporal stretching algorithm of the windowed postcompression RF echo signal. The authors examine these methods using 2D finite element simulations and resulting experimental strain filters. Finally, the combination of these two methods is shown to produce an elastogram with higher dynamic range as well as SNR/sub e/.
{"title":"Methods for dynamic range expansion and enhancement of the signal-to-noise ratio in elastography","authors":"E. Konofagou, S. Alam, J. Ophir, T. Krouskop","doi":"10.1109/ULTSYM.1997.661783","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661783","url":null,"abstract":"Two methods are discussed to increase the dynamic range and enhance the signal-to-noise ratio in elastography (SNR/sub e/). One method uses variable applied strains to expand the elastographic dynamic range by selecting the strain estimates with the highest SNR/sub e/ out of a multitude of strain estimates. The second one is a completely new estimator that estimates the strain by an iterative temporal stretching algorithm of the windowed postcompression RF echo signal. The authors examine these methods using 2D finite element simulations and resulting experimental strain filters. Finally, the combination of these two methods is shown to produce an elastogram with higher dynamic range as well as SNR/sub e/.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82545031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-05DOI: 10.1109/ULTSYM.1997.661789
N. Kudo, T. Kamataki, K. Yamamoto, H. Onozuka, T. Mikami, A. Kitabatake, Y. Ito, H. Kanda
The authors developed a measurement system of ultrasound attenuation in the frequency range of 2.5 to 40 MHz and measured the ultrasound attenuation coefficients of normal, infarcted, and dilated cardiomyopathy samples of a human formalized myocardium. Results of attenuation measurements showed that the attenuation coefficients increased proportionally to the n-th power of frequency in the measured frequency range. Attenuation coefficients in the myocardium specimens increased proportionally to the 1.3 power for the infarction and 1.2 power for the dilated cardiomyopathy of frequency, respectively, while the attenuation coefficient increased proportionally to the 1.6 power for the normal myocardium. These results suggest that an exponent of frequency-dependent attenuation could be used as an index of tissue characterization.
{"title":"Ultrasound attenuation measurement of tissue in frequency range 2.5-40 MHz using a multi-resonance transducer","authors":"N. Kudo, T. Kamataki, K. Yamamoto, H. Onozuka, T. Mikami, A. Kitabatake, Y. Ito, H. Kanda","doi":"10.1109/ULTSYM.1997.661789","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661789","url":null,"abstract":"The authors developed a measurement system of ultrasound attenuation in the frequency range of 2.5 to 40 MHz and measured the ultrasound attenuation coefficients of normal, infarcted, and dilated cardiomyopathy samples of a human formalized myocardium. Results of attenuation measurements showed that the attenuation coefficients increased proportionally to the n-th power of frequency in the measured frequency range. Attenuation coefficients in the myocardium specimens increased proportionally to the 1.3 power for the infarction and 1.2 power for the dilated cardiomyopathy of frequency, respectively, while the attenuation coefficient increased proportionally to the 1.6 power for the normal myocardium. These results suggest that an exponent of frequency-dependent attenuation could be used as an index of tissue characterization.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80932460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-05DOI: 10.1109/ULTSYM.1997.661765
S. Bridal, J. Toussaint, J. Raynaud, P. Fornés, A. Leroy-Willig, G. Berger
This study compares quantitative characterization of plaque by high resolution estimates of ultrasonic attenuation, ultrasonic backscatter and magnetic resonance transverse relaxation time. A total of 54 regions of in vitro human arteries were studied. Backscattered radio frequency signals were acquired with a 50 MHz backscatter acoustic microscope. Ultrasonic parametric images were constructed from the integrated (30 to 50 MHz) backscatter and attenuation obtained using FFT methods with diffraction correction and a multinarrow-band attenuation algorithm. Magnetic resonance images were constructed from estimates of the transverse relaxation time determined by an 8 echo-monoslice sequence at 3 Tesla. Histological segments obtained at each measurement site were used to identify tissue composition. Results suggest that combined ultrasound and magnetic resonance techniques may offer complementary information for plaque characterization.
{"title":"Multi-parametric imaging of atherosclerotic plaque by 50 MHz ultrasound and 3 Tesla magnetic resonance","authors":"S. Bridal, J. Toussaint, J. Raynaud, P. Fornés, A. Leroy-Willig, G. Berger","doi":"10.1109/ULTSYM.1997.661765","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.661765","url":null,"abstract":"This study compares quantitative characterization of plaque by high resolution estimates of ultrasonic attenuation, ultrasonic backscatter and magnetic resonance transverse relaxation time. A total of 54 regions of in vitro human arteries were studied. Backscattered radio frequency signals were acquired with a 50 MHz backscatter acoustic microscope. Ultrasonic parametric images were constructed from the integrated (30 to 50 MHz) backscatter and attenuation obtained using FFT methods with diffraction correction and a multinarrow-band attenuation algorithm. Magnetic resonance images were constructed from estimates of the transverse relaxation time determined by an 8 echo-monoslice sequence at 3 Tesla. Histological segments obtained at each measurement site were used to identify tissue composition. Results suggest that combined ultrasound and magnetic resonance techniques may offer complementary information for plaque characterization.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80359167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-10-05DOI: 10.1109/ULTSYM.1997.663314
T. R. Gururaja, A. Shurland, J. Chen
We present a novel type of ultrasonic imaging transducer in which the operating frequency can be switched between two distinct bands centered about f/sub 0/ and 2f/sub 0/. In effect, we can achieve greater than 100% transducer bandwidth at the -6 dB level. The transducer is based on using DC bias induced piezoelectricity in electrostrictive materials such as lead magnesium niobate-lead titanate (PMN-PT) relaxor ferroelectric materials.
{"title":"Medical ultrasonic transducers with switchable frequency bands centered about f/sub 0/ and 2f/sub 0/","authors":"T. R. Gururaja, A. Shurland, J. Chen","doi":"10.1109/ULTSYM.1997.663314","DOIUrl":"https://doi.org/10.1109/ULTSYM.1997.663314","url":null,"abstract":"We present a novel type of ultrasonic imaging transducer in which the operating frequency can be switched between two distinct bands centered about f/sub 0/ and 2f/sub 0/. In effect, we can achieve greater than 100% transducer bandwidth at the -6 dB level. The transducer is based on using DC bias induced piezoelectricity in electrostrictive materials such as lead magnesium niobate-lead titanate (PMN-PT) relaxor ferroelectric materials.","PeriodicalId":6369,"journal":{"name":"1997 IEEE Ultrasonics Symposium Proceedings. An International Symposium (Cat. No.97CH36118)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1997-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78844571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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