Pub Date : 1999-10-17DOI: 10.1109/ULTSYM.1999.849246
K. D. Donohue, L. Huang, V. Genis, F. Forsberg
This paper presents results from ultrasonic simulation and phantom studies to demonstrate the performance of generalized spectrum techniques in detecting and estimating duct structures on the order of those in breast tissue. Results demonstrate accurate estimation (about 12% mean square error) and reliable detection (90% or greater) in the presence of diffuse scatterers and system noise.
{"title":"Duct size detection and estimation in breast tissue","authors":"K. D. Donohue, L. Huang, V. Genis, F. Forsberg","doi":"10.1109/ULTSYM.1999.849246","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849246","url":null,"abstract":"This paper presents results from ultrasonic simulation and phantom studies to demonstrate the performance of generalized spectrum techniques in detecting and estimating duct structures on the order of those in breast tissue. Results demonstrate accurate estimation (about 12% mean square error) and reliable detection (90% or greater) in the presence of diffuse scatterers and system noise.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126800517","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849465
J. Hyslop, G. Hayward
This paper describes a methodology for the prediction of Lamb wave dispersion in piezoceramic and 1-3 piezocomposite materials. The approach is applicable to both experimental measurement and theoretical modelling using a time domain finite element (FE) code, PZFlex. Initially, the dispersion characteristics of polymeric, poled and unpoled Lead Zirconate Titanate type 5H (PZT5H) piezoceramic materials are derived. The technique is then extended to dual-phase materials, whereby a series of piezoceramic pillars or planks are embedded in a polymer matrix to form a 1-3 piezocomposite material. Finally, the influence of Lamb wave propagation on transducer behaviour is studied for a single-element rectangular transducer, defined in the centre of a piezocomposite substrate. The Lamb wave modes supported in the structure are identified, and their degrading effect on element surface displacement and beamwidth noted. A second transducer array, incorporating a high-loss polymer in the passive phase of the 1-3 material is examined. The improvement in element beamwidth for this device illustrates the benefits of ensuring Lamb wave propagation in any transducer structure is kept to a minimum through judicial transducer design. Throughout this investigation, excellent agreement is achieved between the measured data gathered from devices fabricated within the Centre for Ultrasonic Engineering, and that generated from the PZFlex finite element (FE) code.
{"title":"The study of Lamb wave dispersion in piezoelectric plate transducers","authors":"J. Hyslop, G. Hayward","doi":"10.1109/ULTSYM.1999.849465","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849465","url":null,"abstract":"This paper describes a methodology for the prediction of Lamb wave dispersion in piezoceramic and 1-3 piezocomposite materials. The approach is applicable to both experimental measurement and theoretical modelling using a time domain finite element (FE) code, PZFlex. Initially, the dispersion characteristics of polymeric, poled and unpoled Lead Zirconate Titanate type 5H (PZT5H) piezoceramic materials are derived. The technique is then extended to dual-phase materials, whereby a series of piezoceramic pillars or planks are embedded in a polymer matrix to form a 1-3 piezocomposite material. Finally, the influence of Lamb wave propagation on transducer behaviour is studied for a single-element rectangular transducer, defined in the centre of a piezocomposite substrate. The Lamb wave modes supported in the structure are identified, and their degrading effect on element surface displacement and beamwidth noted. A second transducer array, incorporating a high-loss polymer in the passive phase of the 1-3 material is examined. The improvement in element beamwidth for this device illustrates the benefits of ensuring Lamb wave propagation in any transducer structure is kept to a minimum through judicial transducer design. Throughout this investigation, excellent agreement is achieved between the measured data gathered from devices fabricated within the Centre for Ultrasonic Engineering, and that generated from the PZFlex finite element (FE) code.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127010419","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849511
B. J. Dean, L. Lynnworth
The hockey stick (OKS) buffer waveguide for high-temperature clamp-on flow velocity measurements of hot water, 260°C, first reported in these Proceedings in 1996 and 1997, has evolved in response to the demands of new applications. Accuracy in some cases is needed not just at the temperature extremes but from room temperature to the extreme, requiring dynamic compensation for changes in sound propagation in the buffers. The operation of the OKS can be monitored by sensing overheating, sound speed distribution and coupling efficiency. Couplants for the -150° <;T<;360°C range must satisfy acoustic requirements and safety concerns. Metal foil couplants have been acceptable in most applications. Measurements of secondary flow have been made with clamp-on transducers, even at a location greater than 30 diameters from the nearest flow disturbance.
{"title":"Hockey stick developments extend range, improve accuracy of clamp-on flow measurements","authors":"B. J. Dean, L. Lynnworth","doi":"10.1109/ULTSYM.1999.849511","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849511","url":null,"abstract":"The hockey stick (OKS) buffer waveguide for high-temperature clamp-on flow velocity measurements of hot water, 260°C, first reported in these Proceedings in 1996 and 1997, has evolved in response to the demands of new applications. Accuracy in some cases is needed not just at the temperature extremes but from room temperature to the extreme, requiring dynamic compensation for changes in sound propagation in the buffers. The operation of the OKS can be monitored by sensing overheating, sound speed distribution and coupling efficiency. Couplants for the -150° <;T<;360°C range must satisfy acoustic requirements and safety concerns. Metal foil couplants have been acceptable in most applications. Measurements of secondary flow have been made with clamp-on transducers, even at a location greater than 30 diameters from the nearest flow disturbance.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123156655","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849412
A. Hachigo, H. Nakahata, K. Itakura, Satoshi Fujii, S. Shikata
Harmonic phenomena for the layered structures have been discussed and show several differences from those for bulk substrates. An equivalent circuit model for the harmonics including velocity dispersion has been presented and compared with experiments. SAW filters up to 10 GHz have been fabricated over one micron line width using the ZnO/diamond structure.
{"title":"10 GHz narrow band SAW filters using diamond","authors":"A. Hachigo, H. Nakahata, K. Itakura, Satoshi Fujii, S. Shikata","doi":"10.1109/ULTSYM.1999.849412","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849412","url":null,"abstract":"Harmonic phenomena for the layered structures have been discussed and show several differences from those for bulk substrates. An equivalent circuit model for the harmonics including velocity dispersion has been presented and compared with experiments. SAW filters up to 10 GHz have been fabricated over one micron line width using the ZnO/diamond structure.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"131 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121536909","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849452
J. Hoffelner, H. Landes, M. Kaltenbacher, R. Lerch
A recently developed finite element method for the numerical simulation of nonlinear sound wave propagation in thermoviscous fluids is presented. Based on the nonlinear wave equation as derived by Kuznetsov, typical effects associated with nonlinear acoustics like generation of higher harmonics and dissipation resulting from the propagation of a finite amplitude wave through a thermoviscous medium are covered. The method is verified by comparison with the well-known Fubini and Fay solutions for plane wave problems, where excellent agreement is found. As a practical application, a high intensity focused ultrasound source is considered. Measurements of the radiated pressure pulse at various distances from the source are compared with corresponding simulation results. The obtained good agreement demonstrates validity and applicability of the nonlinear finite element method.
{"title":"Numerical simulation of nonlinear wave propagation in thermoviscous fluids including dissipation","authors":"J. Hoffelner, H. Landes, M. Kaltenbacher, R. Lerch","doi":"10.1109/ULTSYM.1999.849452","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849452","url":null,"abstract":"A recently developed finite element method for the numerical simulation of nonlinear sound wave propagation in thermoviscous fluids is presented. Based on the nonlinear wave equation as derived by Kuznetsov, typical effects associated with nonlinear acoustics like generation of higher harmonics and dissipation resulting from the propagation of a finite amplitude wave through a thermoviscous medium are covered. The method is verified by comparison with the well-known Fubini and Fay solutions for plane wave problems, where excellent agreement is found. As a practical application, a high intensity focused ultrasound source is considered. Measurements of the radiated pressure pulse at various distances from the source are compared with corresponding simulation results. The obtained good agreement demonstrates validity and applicability of the nonlinear finite element method.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125997246","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849321
K. Morgan, J. Allen, J. Chomas, P. Dayton, K. Ferrara
An improved understanding of contrast agent behavior may yield more sophisticated bubble detection techniques. In this study, the optical measurements of single bubble oscillations during insonation are compared directly to theoretical predictions. These results are then used to aid in the understanding of the effects of transmission and bubble parameters on the bubble oscillations and resulting received echoes. A Rayleigh-Plesset-like bubble equation with additional shell terms is solved for the time dependent bubble radius and wall velocity, and these outputs are also used to formulate the predicted echo from a single encapsulated bubble. The experimental and theoretical radius-time curves are in good agreement; with a consistent, predictable response from the lipid-shelled agent with varying amplitude, phase and length of the transmission pulses. The radius-time curves of the albumin-shelled agent Optison/sup TM/ are less predictable due to its asymmetric oscillations. Observations of the effects of transmitted phase and the corresponding predicted echoes are consistent with previous experimental results. These results demonstrate that the transmission of two pulses with opposite phases will yield similar time domain echoes with the echo from the pulse with rarefaction first (180/spl deg/) having a mean frequency that is higher than the compression first response (0/spl deg/).
{"title":"Experimental and theoretical analysis of individual contrast agent behavior","authors":"K. Morgan, J. Allen, J. Chomas, P. Dayton, K. Ferrara","doi":"10.1109/ULTSYM.1999.849321","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849321","url":null,"abstract":"An improved understanding of contrast agent behavior may yield more sophisticated bubble detection techniques. In this study, the optical measurements of single bubble oscillations during insonation are compared directly to theoretical predictions. These results are then used to aid in the understanding of the effects of transmission and bubble parameters on the bubble oscillations and resulting received echoes. A Rayleigh-Plesset-like bubble equation with additional shell terms is solved for the time dependent bubble radius and wall velocity, and these outputs are also used to formulate the predicted echo from a single encapsulated bubble. The experimental and theoretical radius-time curves are in good agreement; with a consistent, predictable response from the lipid-shelled agent with varying amplitude, phase and length of the transmission pulses. The radius-time curves of the albumin-shelled agent Optison/sup TM/ are less predictable due to its asymmetric oscillations. Observations of the effects of transmitted phase and the corresponding predicted echoes are consistent with previous experimental results. These results demonstrate that the transmission of two pulses with opposite phases will yield similar time domain echoes with the echo from the pulse with rarefaction first (180/spl deg/) having a mean frequency that is higher than the compression first response (0/spl deg/).","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127947871","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849191
J. Cannata, Jinyan Zhao, S. Ayyappan, T. Ritter, Wo-Hsing Chen, K. Shung
The design and fabrication of high frequency single element ultrasonic transducers present a multitude of challenges for the transducer engineer, from size constraints to electrical impedance matching. This paper discusses the trade-offs involved in procedures used to fabricate lithium niobate (LiNbO/sub 3/) and lead titanate (PbTiO/sub 3/) transducers in the 25 MHz to 75 MHz range. Transducers of varying dimensions were built according to an f-number range of 2-3.5. Desired focal depths were achieved with use of either an acoustic lens or a spherically focused piezoceramic. Silver epoxy backing with an acoustic impedance of approximately 5.9 MRayls was used in all designs. All transducers were designed around a 50/spl Omega/ send and receive circuit. Electrical tuning of the transducer to the receive circuitry was achieved by using an RF transformer and/or a length of coaxial cable. All transducers were tested in a pulse-echo arrangement using a Panametrics 5900PR pulser, a Wavetek function generator and a LeCroy digital oscilloscope. The bandwidth, insertion loss, and depth of focus were measured. Numerous transducers were fabricated with -6 dB bandwidths ranging from 40% to 74%, and two-way insertion loss values ranging from -14 dB to -28 dB.
{"title":"Fabrication of high frequency (25-75 MHz) single element ultrasonic transducers","authors":"J. Cannata, Jinyan Zhao, S. Ayyappan, T. Ritter, Wo-Hsing Chen, K. Shung","doi":"10.1109/ULTSYM.1999.849191","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849191","url":null,"abstract":"The design and fabrication of high frequency single element ultrasonic transducers present a multitude of challenges for the transducer engineer, from size constraints to electrical impedance matching. This paper discusses the trade-offs involved in procedures used to fabricate lithium niobate (LiNbO/sub 3/) and lead titanate (PbTiO/sub 3/) transducers in the 25 MHz to 75 MHz range. Transducers of varying dimensions were built according to an f-number range of 2-3.5. Desired focal depths were achieved with use of either an acoustic lens or a spherically focused piezoceramic. Silver epoxy backing with an acoustic impedance of approximately 5.9 MRayls was used in all designs. All transducers were designed around a 50/spl Omega/ send and receive circuit. Electrical tuning of the transducer to the receive circuitry was achieved by using an RF transformer and/or a length of coaxial cable. All transducers were tested in a pulse-echo arrangement using a Panametrics 5900PR pulser, a Wavetek function generator and a LeCroy digital oscilloscope. The bandwidth, insertion loss, and depth of focus were measured. Numerous transducers were fabricated with -6 dB bandwidths ranging from 40% to 74%, and two-way insertion loss values ranging from -14 dB to -28 dB.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129986616","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849153
P. Verardi, F. Craciun, M. Dincscu
Local piezoelectric measurements, performed on PZT thin films and on electrostrictive PMN-PT plates, subjected to very high d.c. electric fields, are presented. The thin films were obtained by pulsed laser deposition from commercial PZT targets. The PMN-PT thin plates where obtained by sintering, via the columbite process. A special device, that allows the local measurement of the piezoelectric constant while the same area of the sample is subjected to the bias field, was constructed. An electrical circuit allows the separation of the two signals in order to have only the low intensity ac. Signal from the film detected by the instrument. The sample can be scanned over its surface and local measurements of the piezoelectric constant can be performed with a spatial resolution of about 1 mm and a sensitivity of less than one tens of pC/N. The d.c electric field can be varied between 0 and few kV/mm. Results concerning spatial variation of the piezoelectric constant of piezoelectric thin films and the induced piezoelectric constant of electrostrictive materials under high intensity bias electric fields are presented and discussed.
{"title":"Local characterization of piezoelectric and electrostrictive thin films subjected to high electric fields","authors":"P. Verardi, F. Craciun, M. Dincscu","doi":"10.1109/ULTSYM.1999.849153","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849153","url":null,"abstract":"Local piezoelectric measurements, performed on PZT thin films and on electrostrictive PMN-PT plates, subjected to very high d.c. electric fields, are presented. The thin films were obtained by pulsed laser deposition from commercial PZT targets. The PMN-PT thin plates where obtained by sintering, via the columbite process. A special device, that allows the local measurement of the piezoelectric constant while the same area of the sample is subjected to the bias field, was constructed. An electrical circuit allows the separation of the two signals in order to have only the low intensity ac. Signal from the film detected by the instrument. The sample can be scanned over its surface and local measurements of the piezoelectric constant can be performed with a spatial resolution of about 1 mm and a sensitivity of less than one tens of pC/N. The d.c electric field can be varied between 0 and few kV/mm. Results concerning spatial variation of the piezoelectric constant of piezoelectric thin films and the induced piezoelectric constant of electrostrictive materials under high intensity bias electric fields are presented and discussed.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130005360","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849129
Pcy Lee, N. Liu, A. Ballato
The three-dimensional equations of linear piezoelectricity with quasi-electrostatic approximation are extended to include losses attributed to the acoustic viscosity and electrical conductivity. These equations are used to investigate the forced thickness vibrations by the thickness excitation in an infinite piezoelectric plate with the most general symmetry. For a harmonic plane wave propagating in an arbitrary direction in an unbounded solid, the complex eigenvalue problem is solved from which the effective elastic stiffness, viscosity, and conductivity are computed from the corresponding frequency-dependent eigenvalues. For the forced thickness vibrations in an infinite plate, the input admittances are obtained and the complex coupling factors are deduced in terms of material properties. Effects of the viscosity and conductivity on the resonance frequencies, modes, attenuation coefficients, time constants and coupling factors are calculated and examined for quartz and ceramic barium titanate plates.
{"title":"Thickness vibrations of piezoelectric plates with dissipation","authors":"Pcy Lee, N. Liu, A. Ballato","doi":"10.1109/ULTSYM.1999.849129","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849129","url":null,"abstract":"The three-dimensional equations of linear piezoelectricity with quasi-electrostatic approximation are extended to include losses attributed to the acoustic viscosity and electrical conductivity. These equations are used to investigate the forced thickness vibrations by the thickness excitation in an infinite piezoelectric plate with the most general symmetry. For a harmonic plane wave propagating in an arbitrary direction in an unbounded solid, the complex eigenvalue problem is solved from which the effective elastic stiffness, viscosity, and conductivity are computed from the corresponding frequency-dependent eigenvalues. For the forced thickness vibrations in an infinite plate, the input admittances are obtained and the complex coupling factors are deduced in terms of material properties. Effects of the viscosity and conductivity on the resonance frequencies, modes, attenuation coefficients, time constants and coupling factors are calculated and examined for quartz and ceramic barium titanate plates.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130097563","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 : 1999-10-17DOI: 10.1109/ULTSYM.1999.849214
M. Lukacs, M. Sayer, G. Lockwood, S. Foster
Piezoelectric ceramics have been patterned by means of laser micromachining to create ultrasonic arrays resonating in the frequency range of 35-45 MHz. The Lumonics PM-844 excimer laser with a KrF gas mixture (248 nm) has been used to micromachine trenches with a width to depth aspect ratio of up to 1:5. By using a projection etch approach, the large aperture of the excimer laser is used to simultaneously ablate the features of a complex geometrical pattern. Pre-poled ceramic structures >20 /spl mu/m wide and >35 /spl mu/m thick have been cut and validated with SEM images. The dielectric, piezoelectric and acoustic properties have been evaluated using an impedance analyser and pulse-echo techniques.
{"title":"Laser micromachined high frequency ultrasonic arrays","authors":"M. Lukacs, M. Sayer, G. Lockwood, S. Foster","doi":"10.1109/ULTSYM.1999.849214","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849214","url":null,"abstract":"Piezoelectric ceramics have been patterned by means of laser micromachining to create ultrasonic arrays resonating in the frequency range of 35-45 MHz. The Lumonics PM-844 excimer laser with a KrF gas mixture (248 nm) has been used to micromachine trenches with a width to depth aspect ratio of up to 1:5. By using a projection etch approach, the large aperture of the excimer laser is used to simultaneously ablate the features of a complex geometrical pattern. Pre-poled ceramic structures >20 /spl mu/m wide and >35 /spl mu/m thick have been cut and validated with SEM images. The dielectric, piezoelectric and acoustic properties have been evaluated using an impedance analyser and pulse-echo techniques.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131169134","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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