Pub Date : 2002-10-08DOI: 10.1109/ULTSYM.2002.1192683
W. Shi, L. Hoff, F. Forsberg
The diagnostic capabilities of ultrasound imaging can be improved with contrast-specific nonlinear imaging modalities such as harmonic and subharmonic imaging. The subharmonic performance of the ultrasound contrast agent Sonazoid/sup /spl reg// (Amersham Health, Oslo, Norway) has been investigated experimentally and numerically for the implementation of subharmonic imaging. Strong subharmonic responses were observed from Sonazoid microbubbles in vitro, in vivo and numerically. In conclusion, the scattered subharmonic signal amplitude increases with the total energy within each insonation pulse and depends strongly on the polarity of short insonation pulses.
{"title":"Subharmonic performance of contrast microbubbles: an experimental and numerical investigation","authors":"W. Shi, L. Hoff, F. Forsberg","doi":"10.1109/ULTSYM.2002.1192683","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1192683","url":null,"abstract":"The diagnostic capabilities of ultrasound imaging can be improved with contrast-specific nonlinear imaging modalities such as harmonic and subharmonic imaging. The subharmonic performance of the ultrasound contrast agent Sonazoid/sup /spl reg// (Amersham Health, Oslo, Norway) has been investigated experimentally and numerically for the implementation of subharmonic imaging. Strong subharmonic responses were observed from Sonazoid microbubbles in vitro, in vivo and numerically. In conclusion, the scattered subharmonic signal amplitude increases with the total energy within each insonation pulse and depends strongly on the polarity of short insonation pulses.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133326535","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 : 2002-10-08DOI: 10.1109/ULTSYM.2002.1193520
Y. Ono, J. Moisan, C. Jen, D. R. França
The development of ultrasonic techniques for imaging and measurements in molten aluminum (Al) using clad buffer rods operated at 10 MHz is presented. The ultrasonic image of a character "N", engraved on a stainless steel plate immersed in molten Al, has been observed at 780/spl deg/C using the focused probe. Inclusion detection experiments have been conducted in reflection configurations involving pitch-catch and pulse-echo modes. The backscattered ultrasonic signals from the silicon carbide particles with an averaged diameter of 50 /spl mu/m suspended in molten Al are successfully detected due to the high signal-to-noise ratio of the clad buffer rods.
{"title":"Development of ultrasonic techniques with buffer rod in molten aluminum","authors":"Y. Ono, J. Moisan, C. Jen, D. R. França","doi":"10.1109/ULTSYM.2002.1193520","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1193520","url":null,"abstract":"The development of ultrasonic techniques for imaging and measurements in molten aluminum (Al) using clad buffer rods operated at 10 MHz is presented. The ultrasonic image of a character \"N\", engraved on a stainless steel plate immersed in molten Al, has been observed at 780/spl deg/C using the focused probe. Inclusion detection experiments have been conducted in reflection configurations involving pitch-catch and pulse-echo modes. The backscattered ultrasonic signals from the silicon carbide particles with an averaged diameter of 50 /spl mu/m suspended in molten Al are successfully detected due to the high signal-to-noise ratio of the clad buffer rods.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"125 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133649764","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 : 2002-10-08DOI: 10.1109/ULTSYM.2002.1192691
R. Karshafian, P. Burns, X. Qi, Mingyu Zhang
A new and promising strategy in cancer therapy targets the proliferating endothelium of a tumour's blood vessels rather than the cells of the cancer itself. Among other advantages, such therapies may evade the drug resistance that many tumours acquire during treatment, rendering the drugs appropriate for long term use. However, because the tumour vasculature lies below the threshold of detection for conventional radiological techniques, new methods are required to determine the effect of such therapy on the tumour microvasculature. The combination of microbubble contrast and nonlinear imaging methods such as pulse inversion Doppler have been shown capable of detecting (but not resolving) flow at the capillary level. In this study, we use a combination of microbubble destruction-reperfusion flow measurement and real time contrast Imaging to assess the effects of an anti-vascular agent ZD6126 (AstraZeneca Inc, NJ) on experimental VX-2 tumours in the rabbit. The active component of this drug, N-acetyl colchinol, causes tubulin depolymerisation, thereby inducing neovascular endothelial cell rounding and subsequent vascular collapse. The effect is selective to tumour blood vessels (whose endothelial cells rely on tubulin for their structure) and is thought to be an acute one, occurring within hours of administration of the drug. Our objectives in this study were to make haemodynamic measurements of tumour blood flow rate and vascular volume, then to use these to determine dose response to the anti-vascular drug and to demonstrate the evolution of this effect with time following drug administration. We intended that the method used should employ a commercially available scanner and be suitable for translation to clinical contrast imaging of breast cancers.
{"title":"Microbubble destruction-reperfusion in the non-invasive measurement of the vascular targeting effects of the anti-cancer drug ZD6126","authors":"R. Karshafian, P. Burns, X. Qi, Mingyu Zhang","doi":"10.1109/ULTSYM.2002.1192691","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1192691","url":null,"abstract":"A new and promising strategy in cancer therapy targets the proliferating endothelium of a tumour's blood vessels rather than the cells of the cancer itself. Among other advantages, such therapies may evade the drug resistance that many tumours acquire during treatment, rendering the drugs appropriate for long term use. However, because the tumour vasculature lies below the threshold of detection for conventional radiological techniques, new methods are required to determine the effect of such therapy on the tumour microvasculature. The combination of microbubble contrast and nonlinear imaging methods such as pulse inversion Doppler have been shown capable of detecting (but not resolving) flow at the capillary level. In this study, we use a combination of microbubble destruction-reperfusion flow measurement and real time contrast Imaging to assess the effects of an anti-vascular agent ZD6126 (AstraZeneca Inc, NJ) on experimental VX-2 tumours in the rabbit. The active component of this drug, N-acetyl colchinol, causes tubulin depolymerisation, thereby inducing neovascular endothelial cell rounding and subsequent vascular collapse. The effect is selective to tumour blood vessels (whose endothelial cells rely on tubulin for their structure) and is thought to be an acute one, occurring within hours of administration of the drug. Our objectives in this study were to make haemodynamic measurements of tumour blood flow rate and vascular volume, then to use these to determine dose response to the anti-vascular drug and to demonstrate the evolution of this effect with time following drug administration. We intended that the method used should employ a commercially available scanner and be suitable for translation to clinical contrast imaging of breast cancers.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133722068","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 : 2002-10-08DOI: 10.1109/ULTSYM.2002.1193499
Q. Xue, A. Abbate, G. Elfbaum, Y. Shui, Haodong Wu
Fabrication of piezo-composite transducers over 20 MHz by the dice-and-fill method is a challenge to the industry. This paper reports a newly developed 20 MHz single element composite transducer using the dice-and-fill method. The transducer exhibited significant improvement in sensitivity of more than 10 dB in measurement of plastics as compared to standard piezo-ceramic transducers having similar size and electrical impedance. The high efficiency of the composite transducer was achieved by optimizing composite design to a configuration with maximum thickness coupling coefficient of the material. Meanwhile, the polymer and ceramic phases of the composite efficiently oscillate in phase. This design also allows the piezo-composite to be fabricated for frequencies higher than 20 MHz with a low aspect ratio where lateral modes usually dominate. However, with the optimized design, lateral modes are suppressed and almost invisible within usable bandwidths up to 40 MHz. Measurement of thin barrier layer samples using the 20MHz composite transducer demonstrated consistent results for a thickness of 0.084 mm, while the standard 20 MHz transducers are only able to resolve thickness above 0.100 mm.
{"title":"A highly efficient 20 MHz piezo-composite transducer for nondestructive characterization of multilayer plastics","authors":"Q. Xue, A. Abbate, G. Elfbaum, Y. Shui, Haodong Wu","doi":"10.1109/ULTSYM.2002.1193499","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1193499","url":null,"abstract":"Fabrication of piezo-composite transducers over 20 MHz by the dice-and-fill method is a challenge to the industry. This paper reports a newly developed 20 MHz single element composite transducer using the dice-and-fill method. The transducer exhibited significant improvement in sensitivity of more than 10 dB in measurement of plastics as compared to standard piezo-ceramic transducers having similar size and electrical impedance. The high efficiency of the composite transducer was achieved by optimizing composite design to a configuration with maximum thickness coupling coefficient of the material. Meanwhile, the polymer and ceramic phases of the composite efficiently oscillate in phase. This design also allows the piezo-composite to be fabricated for frequencies higher than 20 MHz with a low aspect ratio where lateral modes usually dominate. However, with the optimized design, lateral modes are suppressed and almost invisible within usable bandwidths up to 40 MHz. Measurement of thin barrier layer samples using the 20MHz composite transducer demonstrated consistent results for a thickness of 0.084 mm, while the standard 20 MHz transducers are only able to resolve thickness above 0.100 mm.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133739328","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 : 2002-10-08DOI: 10.1109/ULTSYM.2002.1192575
O. Al-Bataineh, R. Meyer, R.E. Newnharn, N. Smith
Miniature, high-frequency piezoelectric ceramic hollow spheres were evaluated for potential use as hydrophones for exposimetry of high intensity ultrasound fields and as minimally invasive ablation devices. As a hydrophone, the hollow sphere has unique characteristics regarding its geometry, dimensions and sensitivity, which make it ideal for use in exposimetry of high pressure fields. Spheres with diameters ranging from 0.7 to 1.0 mm and with resonance frequencies from 1.8 to 2.7 MHz were used as hydrophones. A relative (reciprocal) calibration method was performed to determine the end-of-cable sensitivity as well as the directivity of the hollow sphere hydrophones. An almost constant sensitivity was reported for the spherical hydrophones and an omni-directional receive pattern was also demonstrated. The hollow sphere hydrophone was shown to have twice the sensitivity of a needle type hydrophone but with no pre-amplification stages and could withstand four times the pressure. As a minimally invasive interstitial ablation device, several in vitro experiments were conducted using two different size spheres. The results demonstrated an increased necrosed tissue volume for increasing exposure time. With a 1.0 mm diameter sphere (f = 1.87 MHz), the necrosed tissue diameter as a function of exposure times was 2.35 /spl plusmn/ 0.34, 3.00 /spl plusmn/ 0.37 and 4.61 /spl plusmn/ 1.13 mm for 5, 10 and 15 second sonications, respectively. Using a 0.7 mm diameter sphere (f = 2.70 MHz), the size of the ablated tissue was 1.50 /spl plusmn/ 0.01 and 1.63 /spl plusmn/ 0.31 mm for 5 and 10 seconds sonications, respectively. As a tissue ablation device, the hollow sphere was able to produce controllable lesion diameters with sharp boundaries between the normal and necrosed tissue.
{"title":"Utilization of the high-frequency piezoelectric ceramic hollow spheres for exposimetry and tissue ablation","authors":"O. Al-Bataineh, R. Meyer, R.E. Newnharn, N. Smith","doi":"10.1109/ULTSYM.2002.1192575","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1192575","url":null,"abstract":"Miniature, high-frequency piezoelectric ceramic hollow spheres were evaluated for potential use as hydrophones for exposimetry of high intensity ultrasound fields and as minimally invasive ablation devices. As a hydrophone, the hollow sphere has unique characteristics regarding its geometry, dimensions and sensitivity, which make it ideal for use in exposimetry of high pressure fields. Spheres with diameters ranging from 0.7 to 1.0 mm and with resonance frequencies from 1.8 to 2.7 MHz were used as hydrophones. A relative (reciprocal) calibration method was performed to determine the end-of-cable sensitivity as well as the directivity of the hollow sphere hydrophones. An almost constant sensitivity was reported for the spherical hydrophones and an omni-directional receive pattern was also demonstrated. The hollow sphere hydrophone was shown to have twice the sensitivity of a needle type hydrophone but with no pre-amplification stages and could withstand four times the pressure. As a minimally invasive interstitial ablation device, several in vitro experiments were conducted using two different size spheres. The results demonstrated an increased necrosed tissue volume for increasing exposure time. With a 1.0 mm diameter sphere (f = 1.87 MHz), the necrosed tissue diameter as a function of exposure times was 2.35 /spl plusmn/ 0.34, 3.00 /spl plusmn/ 0.37 and 4.61 /spl plusmn/ 1.13 mm for 5, 10 and 15 second sonications, respectively. Using a 0.7 mm diameter sphere (f = 2.70 MHz), the size of the ablated tissue was 1.50 /spl plusmn/ 0.01 and 1.63 /spl plusmn/ 0.31 mm for 5 and 10 seconds sonications, respectively. As a tissue ablation device, the hollow sphere was able to produce controllable lesion diameters with sharp boundaries between the normal and necrosed tissue.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131778523","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 : 2002-10-08DOI: 10.1109/ULTSYM.2002.1193359
A. Miyamoto, S. Wakana, A. Ito
We developed a new optical technique for observing the shear horizontal component of surface acoustic waves. The technique detects the change in polarization of the probe light caused by the photoelastic effect. We measured the distribution in and around a resonator on rotated Y-cut LiTaO/sub 3/, and occurrence and propagation of leakage was observed.
{"title":"Novel optical observation technique for shear horizontal wave in SAW resonators on 42/spl deg/YX-cut lithium tantalate","authors":"A. Miyamoto, S. Wakana, A. Ito","doi":"10.1109/ULTSYM.2002.1193359","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1193359","url":null,"abstract":"We developed a new optical technique for observing the shear horizontal component of surface acoustic waves. The technique detects the change in polarization of the probe light caused by the photoelastic effect. We measured the distribution in and around a resonator on rotated Y-cut LiTaO/sub 3/, and occurrence and propagation of leakage was observed.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132187346","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 : 2002-10-08DOI: 10.1109/ULTSYM.2002.1193362
S. Kanna, K. Iizawa, T. Yamazaki, M. Takagi
We present surface acoustic wave resonators on the in-plane rotated 33/spl deg/Y-cut quartz with improved temperature stability. We calculate the frequency temperature characteristics of Rayleigh waves using finite element method under the condition of Euler angle (0, 123, 39-44). We confirmed the accuracy of calculated temperature coefficients by experiments. We also measured the resonance characteristics of prototype SAW resonators.
{"title":"Temperature stability of surface acoustic wave resonators on the in-plane rotated 33/spl deg/Y-cut quartz","authors":"S. Kanna, K. Iizawa, T. Yamazaki, M. Takagi","doi":"10.1109/ULTSYM.2002.1193362","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1193362","url":null,"abstract":"We present surface acoustic wave resonators on the in-plane rotated 33/spl deg/Y-cut quartz with improved temperature stability. We calculate the frequency temperature characteristics of Rayleigh waves using finite element method under the condition of Euler angle (0, 123, 39-44). We confirmed the accuracy of calculated temperature coefficients by experiments. We also measured the resonance characteristics of prototype SAW resonators.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132295403","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 : 2002-10-08DOI: 10.1109/ULTSYM.2002.1193399
S. Malocha, B. Abbott
In this paper a fast and accurate method to calculate COM parameters (transduction and reflectivity) of a transducer cell with any arbitrary geometry and polarity sequence is presented. This method was applied to optimization of SPUDT cells on different materials. SPUDT structures with three and four electrodes per wavelength have been optimized for several different substrates. Very good agreement between predicted and experimental results is shown for SPUDT transducers on quartz, langasite and lithium tantalate.
{"title":"Calculation of COM parameters for an arbitrary IDT cell","authors":"S. Malocha, B. Abbott","doi":"10.1109/ULTSYM.2002.1193399","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1193399","url":null,"abstract":"In this paper a fast and accurate method to calculate COM parameters (transduction and reflectivity) of a transducer cell with any arbitrary geometry and polarity sequence is presented. This method was applied to optimization of SPUDT cells on different materials. SPUDT structures with three and four electrodes per wavelength have been optimized for several different substrates. Very good agreement between predicted and experimental results is shown for SPUDT transducers on quartz, langasite and lithium tantalate.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134181029","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 : 2002-10-08DOI: 10.1109/ULTSYM.2002.1192486
S. Takeuchi, M.R.A. Al Zaabi, T. Sato, N. Kawashima
In this study, an ultrasound transducer with double peak type frequency characteristics having a peak on the high frequency side for illuminating ultrasound to tissues or microbubbles in the human body and a peak on the low frequency side for detecting sub-harmonic component from microbubbles was designed with numerical calculations and fabricated as the one for sub-harmonic imaging. The trial ultrasound transducer was confirmed to have the double peak type frequency characteristics of transmitting and receiving sensitivity adapted to sub-harmonic imaging.
{"title":"Study on ultrasound transducer with double peak type frequency characteristics for sub-harmonic imaging","authors":"S. Takeuchi, M.R.A. Al Zaabi, T. Sato, N. Kawashima","doi":"10.1109/ULTSYM.2002.1192486","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1192486","url":null,"abstract":"In this study, an ultrasound transducer with double peak type frequency characteristics having a peak on the high frequency side for illuminating ultrasound to tissues or microbubbles in the human body and a peak on the low frequency side for detecting sub-harmonic component from microbubbles was designed with numerical calculations and fabricated as the one for sub-harmonic imaging. The trial ultrasound transducer was confirmed to have the double peak type frequency characteristics of transmitting and receiving sensitivity adapted to sub-harmonic imaging.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125699525","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 : 2002-10-08DOI: 10.1109/ULTSYM.2002.1193415
V.I. Grigorievski
It is shown that effective permittivity function in the complex plane of slowness for 36-42 degrees rotated lithium tantalate substrates apart from the well-known LSAW exhibits an additional singular point. The pole is located between "fast shear" and "longitudinal" branch points and can be numerically found out when appropriate branch line is drawn from the "fast shear" branch point. The effective propagation velocity of this leaky mode on 36 degrees rotated lithium tantalate equals 4723 m/s that is 1.1 times larger than the velocity of fast shear SSBW propagating in the same direction. The intrinsic attenuation of this mode is extremely high and equal to 6.93 dB/wavelength. The previously reported PSAW-like mode in periodic system of metal electrodes is associated with this new mode.
{"title":"Interaction between leaky surface acoustic waves in periodic gratings of thick metal electrodes","authors":"V.I. Grigorievski","doi":"10.1109/ULTSYM.2002.1193415","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1193415","url":null,"abstract":"It is shown that effective permittivity function in the complex plane of slowness for 36-42 degrees rotated lithium tantalate substrates apart from the well-known LSAW exhibits an additional singular point. The pole is located between \"fast shear\" and \"longitudinal\" branch points and can be numerically found out when appropriate branch line is drawn from the \"fast shear\" branch point. The effective propagation velocity of this leaky mode on 36 degrees rotated lithium tantalate equals 4723 m/s that is 1.1 times larger than the velocity of fast shear SSBW propagating in the same direction. The intrinsic attenuation of this mode is extremely high and equal to 6.93 dB/wavelength. The previously reported PSAW-like mode in periodic system of metal electrodes is associated with this new mode.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134621141","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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