Pub Date : 1995-11-07DOI: 10.1109/ULTSYM.1995.495833
I. Hein
Current commercial ultrasound blood flow measurement systems only measure the axial component of the true blood flow velocity vector. In order to overcome this limitation, a technique which tracks blood cell scatterers as as they move between three ultrasound beams has been developed. With this technique, the entire three-dimensional blood flow velocity vector can be estimated. Previous work has presented the theory behind the technique as well as results of computer simulations. This work presents the first experimental results obtained with a prototype system for continuous, fully developed flow in a flow phantom under a wide range of flow rates and flow directions. The results indicate that the accurate measurement of the 3-D flow velocity vector using this technique is possible.
{"title":"3-D blood flow velocity estimation with a triple-beam lens-experimental results","authors":"I. Hein","doi":"10.1109/ULTSYM.1995.495833","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495833","url":null,"abstract":"Current commercial ultrasound blood flow measurement systems only measure the axial component of the true blood flow velocity vector. In order to overcome this limitation, a technique which tracks blood cell scatterers as as they move between three ultrasound beams has been developed. With this technique, the entire three-dimensional blood flow velocity vector can be estimated. Previous work has presented the theory behind the technique as well as results of computer simulations. This work presents the first experimental results obtained with a prototype system for continuous, fully developed flow in a flow phantom under a wide range of flow rates and flow directions. The results indicate that the accurate measurement of the 3-D flow velocity vector using this technique is possible.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121803482","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 : 1995-11-07DOI: 10.1109/ULTSYM.1995.495712
C. Seabury, J. Cheung, P. Kobrin, R. Addison, D. P. Havens
We have used pulsed laser deposition and a dry release process to produce freestanding zinc oxide films for bulk mode microwave acoustic resonators. Laser assisted deposition is used to produce ZnO films with very low (slightly tensile) stress at temperatures below 200/spl deg/C. They have a high degree of orientation, C axis X-ray 1/2 width /spl sim/0.24/spl deg/, resistivity greater than 10/sup 10/ ohm cm and loss tangent below 0.01 at 10 MHz. Resonators with Qs of over 350 with K/sub em/ of 0.22 at 1.5 GHz have been produced. An air-bridge process has been used to produce undistorted freestanding membranes up to 400 /spl mu/m sq., with single mode resonance characteristics. The use of an inorganic sacrificial layer and a dry release etch avoids the problem of surface tension that occurs in wet chemical etching, resulting in high yield. The process also allows for on-wafer frequency trimming. Multipole band pass filters have been designed based on the discrete resonator results, and have been fabricated using this process. A rejection of 28 dB and an insertion loss of -7 dB have been achieved. The high yield and good uniformity make this a practical, low-cost process for producing complex multipole filter structures suitable for 1-3 GHz mobile communications.
{"title":"High performance microwave air-bridge resonators","authors":"C. Seabury, J. Cheung, P. Kobrin, R. Addison, D. P. Havens","doi":"10.1109/ULTSYM.1995.495712","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495712","url":null,"abstract":"We have used pulsed laser deposition and a dry release process to produce freestanding zinc oxide films for bulk mode microwave acoustic resonators. Laser assisted deposition is used to produce ZnO films with very low (slightly tensile) stress at temperatures below 200/spl deg/C. They have a high degree of orientation, C axis X-ray 1/2 width /spl sim/0.24/spl deg/, resistivity greater than 10/sup 10/ ohm cm and loss tangent below 0.01 at 10 MHz. Resonators with Qs of over 350 with K/sub em/ of 0.22 at 1.5 GHz have been produced. An air-bridge process has been used to produce undistorted freestanding membranes up to 400 /spl mu/m sq., with single mode resonance characteristics. The use of an inorganic sacrificial layer and a dry release etch avoids the problem of surface tension that occurs in wet chemical etching, resulting in high yield. The process also allows for on-wafer frequency trimming. Multipole band pass filters have been designed based on the discrete resonator results, and have been fabricated using this process. A rejection of 28 dB and an insertion loss of -7 dB have been achieved. The high yield and good uniformity make this a practical, low-cost process for producing complex multipole filter structures suitable for 1-3 GHz mobile communications.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127434632","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 : 1995-11-07DOI: 10.1109/ULTSYM.1995.495746
J. Hawkes, M. S. Limaye, W. Coakley
Continuous flow filtration of cell suspensions has recently become possible using ultrasound standing wave enhanced sedimentation. A filter which can be operated at either 1 or 3 MHz is described. At both 1 MHz and 3 MHz yeast cells (4.6 /spl mu/m diameter) can be filtered at greater than 99% efficiency at a flow rate of 5 ml min/sup -1/. Smaller cells such as E. coli (1.3 /spl mu/m diameter) were efficiently filtered at 3 MHz. This frequency dependent filtration suggests two modes of operations as (1) a filter to remove cells from suspension, or (2) a separator to separate a mixture of large (yeast) and small (E. coli) cells.
{"title":"An ultrasonic method for filtering and separating cell suspensions","authors":"J. Hawkes, M. S. Limaye, W. Coakley","doi":"10.1109/ULTSYM.1995.495746","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495746","url":null,"abstract":"Continuous flow filtration of cell suspensions has recently become possible using ultrasound standing wave enhanced sedimentation. A filter which can be operated at either 1 or 3 MHz is described. At both 1 MHz and 3 MHz yeast cells (4.6 /spl mu/m diameter) can be filtered at greater than 99% efficiency at a flow rate of 5 ml min/sup -1/. Smaller cells such as E. coli (1.3 /spl mu/m diameter) were efficiently filtered at 3 MHz. This frequency dependent filtration suggests two modes of operations as (1) a filter to remove cells from suspension, or (2) a separator to separate a mixture of large (yeast) and small (E. coli) cells.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124830299","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 : 1995-11-07DOI: 10.1109/ULTSYM.1995.495844
P. Tortoli, F. Guidi
A novel ultrasound multigate system, capable of computing in real-time the FFT of Doppler signals from 64 range cells, is proven suitable for detection of low blood velocities. By imposing appropriate weighting windows to the signals that are to be Fourier transformed, possible clutter components are restricted within a few frequency bins. Filtering, where really necessary, is limited to a first-order IIR HPF. Hence, most of the information related to useful Doppler frequencies are maintained. In particular, the maximum frequency of each spectrum, which is known to be related to the maximum velocity within the corresponding sample volume, turns out to be, to a large extent, unaffected by clutter. Detection of maximum frequencies from the various sample volumes is thus proposed as a reliable means to reconstruct the true profile down to velocities proximal to zero.
{"title":"Detection of low velocities by a novel ultrasound multigate system","authors":"P. Tortoli, F. Guidi","doi":"10.1109/ULTSYM.1995.495844","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495844","url":null,"abstract":"A novel ultrasound multigate system, capable of computing in real-time the FFT of Doppler signals from 64 range cells, is proven suitable for detection of low blood velocities. By imposing appropriate weighting windows to the signals that are to be Fourier transformed, possible clutter components are restricted within a few frequency bins. Filtering, where really necessary, is limited to a first-order IIR HPF. Hence, most of the information related to useful Doppler frequencies are maintained. In particular, the maximum frequency of each spectrum, which is known to be related to the maximum velocity within the corresponding sample volume, turns out to be, to a large extent, unaffected by clutter. Detection of maximum frequencies from the various sample volumes is thus proposed as a reliable means to reconstruct the true profile down to velocities proximal to zero.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124893204","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 : 1995-11-07DOI: 10.1109/ULTSYM.1995.495535
P. Wright, D. F. Thompson, R. Chang
A new family of Dithered Single-Phase Unidirectional Transducer (DSPUDT) configurations is described. These structures are comprised of uniform width single-level electrodes on a non-uniform grid. They are an extension of the uniformly-sampled 3/spl lambda//8 and 5/spl lambda//8 double-level SPUDT configurations introduced in 1992. Instead of employing a double-level metalization, unidirectionality is achieved in these new structures by dithering the position of the electrodes. This technique is very powerful as it allows the reflectivity function in the transducer to be implemented in a near analogue fashion, rather than a discrete approximation. In addition to mean sampling rates of 3/spl lambda//8 and 5/spl lambda//8, other sampling rates are considered of the general form m/spl lambda//n and (1-m/n)/spl lambda/, where m and n are integers and m/spl les/n/2. These additional sampling rates provide additional flexibility for making design tradeoffs in the minimum critical geometry, implemented coupling and reflection coefficients, and undesired out-of-band responses in the transducer. Using combinations of these sampling rates, filters with excellent rejection characteristics can be constructed. The large critical geometry's possible with these new transducers permits low-loss filters to be easily fabricated at frequencies in excess of 1 GHz with very linear group-delay and high out-of-band rejection.
{"title":"Single-phase unidirectional transducers employing uniform-width dithered electrodes","authors":"P. Wright, D. F. Thompson, R. Chang","doi":"10.1109/ULTSYM.1995.495535","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495535","url":null,"abstract":"A new family of Dithered Single-Phase Unidirectional Transducer (DSPUDT) configurations is described. These structures are comprised of uniform width single-level electrodes on a non-uniform grid. They are an extension of the uniformly-sampled 3/spl lambda//8 and 5/spl lambda//8 double-level SPUDT configurations introduced in 1992. Instead of employing a double-level metalization, unidirectionality is achieved in these new structures by dithering the position of the electrodes. This technique is very powerful as it allows the reflectivity function in the transducer to be implemented in a near analogue fashion, rather than a discrete approximation. In addition to mean sampling rates of 3/spl lambda//8 and 5/spl lambda//8, other sampling rates are considered of the general form m/spl lambda//n and (1-m/n)/spl lambda/, where m and n are integers and m/spl les/n/2. These additional sampling rates provide additional flexibility for making design tradeoffs in the minimum critical geometry, implemented coupling and reflection coefficients, and undesired out-of-band responses in the transducer. Using combinations of these sampling rates, filters with excellent rejection characteristics can be constructed. The large critical geometry's possible with these new transducers permits low-loss filters to be easily fabricated at frequencies in excess of 1 GHz with very linear group-delay and high out-of-band rejection.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123274491","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 : 1995-11-07DOI: 10.1109/ULTSYM.1995.495647
V. Khokhlova, O. Rudenko
Theoretical approach for the description of nonlinear acoustic waves transmitted through randomly inhomogeneous thin layer (phase screen) is presented. An exact analytical solutions of governing equations are obtained both for the spatial structure of the field behind the screen and for the temporal waveform. Using this model statistical characteristic of a single N-pulse having passed through the screen is studied. The influence of the random focusing and defocusing effect on the statistical properties of N-wave behind the screen is analyzed. Distribution functions for the shock amplitude, overpressure probability density, and ray convergency are presented. It is shown that the spatial modulation of the phase front affects the average characteristics of the field and causes the strong variations of the wave field parameters.
{"title":"Model of the phase screen for nonlinear acoustic waves [atmosphere]","authors":"V. Khokhlova, O. Rudenko","doi":"10.1109/ULTSYM.1995.495647","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495647","url":null,"abstract":"Theoretical approach for the description of nonlinear acoustic waves transmitted through randomly inhomogeneous thin layer (phase screen) is presented. An exact analytical solutions of governing equations are obtained both for the spatial structure of the field behind the screen and for the temporal waveform. Using this model statistical characteristic of a single N-pulse having passed through the screen is studied. The influence of the random focusing and defocusing effect on the statistical properties of N-wave behind the screen is analyzed. Distribution functions for the shock amplitude, overpressure probability density, and ray convergency are presented. It is shown that the spatial modulation of the phase front affects the average characteristics of the field and causes the strong variations of the wave field parameters.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126603011","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 : 1995-11-07DOI: 10.1109/ULTSYM.1995.495547
E. Danicki
New SAW components are proposed and analyzed with help of the spectral theory. They are: closed and opened Modal Reflecting Structures (MRS), Magic Multistrip Mirror (MMM), and Reversing Transducer System (RTS), all of which can be applied to 2-channel SAW resonator filters, substituting Reversing MultiStrip Couplers (RMSC) there. The principle of operation of MRSs are similar to that of RMSCs, however, different connections between their electrodes results in only one mode of a pair of two that can propagate in the structure in a given direction being reflected in a stopband; the other mode is a propagating one for which the structure of MRS is transparent. Results of simple experiments verify the concepts of MRSs which, like RMSCs, have 3 strips per wavelength and similar stopband width, 2/3/spl Delta/v/v, relatively. In the RTS, appropriately connected IDTs are applied instead of strips in the RMSC (an analogue to IIDT). In the Magic Multistrip Mirror, which is also a double channel device, the track-changing phenomenon results from different phases (by 180/spl deg/) of Bragg reflected SAWs from short-circuited and opened metal strip gratings which, in the MMM, are accompanied by a shallow groove grating with the same period. Its relative working bandwidth is /spl sim/ 1/4 /spl Delta/v/v. Particular attention is paid to the admittances of one port double channel SAW resonators comprising the above reflecting structures which can be exploited in ladder filters utilizing SAW admittance elements.
{"title":"Novel SAW components for low-loss filters","authors":"E. Danicki","doi":"10.1109/ULTSYM.1995.495547","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495547","url":null,"abstract":"New SAW components are proposed and analyzed with help of the spectral theory. They are: closed and opened Modal Reflecting Structures (MRS), Magic Multistrip Mirror (MMM), and Reversing Transducer System (RTS), all of which can be applied to 2-channel SAW resonator filters, substituting Reversing MultiStrip Couplers (RMSC) there. The principle of operation of MRSs are similar to that of RMSCs, however, different connections between their electrodes results in only one mode of a pair of two that can propagate in the structure in a given direction being reflected in a stopband; the other mode is a propagating one for which the structure of MRS is transparent. Results of simple experiments verify the concepts of MRSs which, like RMSCs, have 3 strips per wavelength and similar stopband width, 2/3/spl Delta/v/v, relatively. In the RTS, appropriately connected IDTs are applied instead of strips in the RMSC (an analogue to IIDT). In the Magic Multistrip Mirror, which is also a double channel device, the track-changing phenomenon results from different phases (by 180/spl deg/) of Bragg reflected SAWs from short-circuited and opened metal strip gratings which, in the MMM, are accompanied by a shallow groove grating with the same period. Its relative working bandwidth is /spl sim/ 1/4 /spl Delta/v/v. Particular attention is paid to the admittances of one port double channel SAW resonators comprising the above reflecting structures which can be exploited in ladder filters utilizing SAW admittance elements.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126868309","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 : 1995-11-07DOI: 10.1109/ULTSYM.1995.495821
J. R. Jackson, P. Benkeser, F. Nichols
The long-term goal of this work is to develop an ultrasound technique that produces a 3-D image of the structure and elasticity of the cervical common carotid artery and its bifurcation, allowing the quantitative measurement of the volume, structure and composition of atherosclerotic plaque at or near the bifurcation. An Acuson 128 imaging system was used to obtain time-gated B-mode images of the carotid in vivo. The motion of the vessel wall due to the changing blood pressure during a cardiac cycle was quantified and used to compute an estimate of the tissue elasticity distribution over each 2-D image plane. The tissue motion direction and amplitude was determined by a 2-D interframe block matching technique performed on a sequence of frames acquired at 18 frames per second. The transducer was moved linearly along the axis of the common carotid in 2 mm increments to collect the set of slices used to form the 3-D image. Volumetric images of the phantom have been made. Elasticity measurements indicate that the tissue motion appears to be an adequate measure for the determination of relative elasticity distributions.
{"title":"3-D ultrasonic imaging of the structure and elasticity of the carotid bifurcation","authors":"J. R. Jackson, P. Benkeser, F. Nichols","doi":"10.1109/ULTSYM.1995.495821","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495821","url":null,"abstract":"The long-term goal of this work is to develop an ultrasound technique that produces a 3-D image of the structure and elasticity of the cervical common carotid artery and its bifurcation, allowing the quantitative measurement of the volume, structure and composition of atherosclerotic plaque at or near the bifurcation. An Acuson 128 imaging system was used to obtain time-gated B-mode images of the carotid in vivo. The motion of the vessel wall due to the changing blood pressure during a cardiac cycle was quantified and used to compute an estimate of the tissue elasticity distribution over each 2-D image plane. The tissue motion direction and amplitude was determined by a 2-D interframe block matching technique performed on a sequence of frames acquired at 18 frames per second. The transducer was moved linearly along the axis of the common carotid in 2 mm increments to collect the set of slices used to form the 3-D image. Volumetric images of the phantom have been made. Elasticity measurements indicate that the tissue motion appears to be an adequate measure for the determination of relative elasticity distributions.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114920592","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 : 1995-11-07DOI: 10.1109/ULTSYM.1995.495587
X. Yin, D. Zhang, P. Wu, J. Yu
This paper presents a quasi-harmonic interdigital transducer (QHIDT) utilized for SAW filters. The QHIDT consists of several single electrode transducers which serve as elemental transducers. The width and position of the electrodes in the elemental transducer was considered to eliminate the inter multi-reflection between the electrodes. Therefore, the center frequency of each element is not exactly the same as the operating frequency of the QHIDT. QHIDT is suitable for high frequency SAW filters because frequencies can be generated at the 2nd, 3rd and 4th harmonic etc. The fundamental frequency signals could be suppressed by using input and output QHIDTs with different order harmonic generation. An experimental prototype device, in which two transducers with different periods were applied, was fabricated on ST cut quartz substrate. The frequency response, at 242.94 MHz operating frequency, is shown. The insertion loss without tuner in a 50 /spl Omega/ system is about 13.8 dB. The theoretical frequency response is also presented.
{"title":"Quasi-harmonic interdigital transducers","authors":"X. Yin, D. Zhang, P. Wu, J. Yu","doi":"10.1109/ULTSYM.1995.495587","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495587","url":null,"abstract":"This paper presents a quasi-harmonic interdigital transducer (QHIDT) utilized for SAW filters. The QHIDT consists of several single electrode transducers which serve as elemental transducers. The width and position of the electrodes in the elemental transducer was considered to eliminate the inter multi-reflection between the electrodes. Therefore, the center frequency of each element is not exactly the same as the operating frequency of the QHIDT. QHIDT is suitable for high frequency SAW filters because frequencies can be generated at the 2nd, 3rd and 4th harmonic etc. The fundamental frequency signals could be suppressed by using input and output QHIDTs with different order harmonic generation. An experimental prototype device, in which two transducers with different periods were applied, was fabricated on ST cut quartz substrate. The frequency response, at 242.94 MHz operating frequency, is shown. The insertion loss without tuner in a 50 /spl Omega/ system is about 13.8 dB. The theoretical frequency response is also presented.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115354793","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 : 1995-11-07DOI: 10.1109/ULTSYM.1995.495722
K. Yamada, B. Khuri-Yakub
Time-of-flight measurements with point-like contact transducers have successfully been applied for the detection of anisotropy, and for in situ measurements of film thickness and temperature. This paper presents a new type of Hertzian-contact transducer of waveguiding structure operating in the MHz range. The transducer is composed of a fused quartz tube and a radially-polarized annular piezoelectric element bonded to one of its ends. The edge-bonded shear-wave transducer effectively excites a surface wave on the interior surface of the tube. A small bullet pin made of quartz is inserted and fixed on the other end of the tube to make a point contact and transmit the wave energy to a specimen to be inspected. Using a pair of these transducers, we have succeeded in the excitation and detection of surface acoustic waves as well as Lamb waves in the 3 MHz frequency range.
{"title":"Point contact transducer of waveguiding structure for high-frequency operation","authors":"K. Yamada, B. Khuri-Yakub","doi":"10.1109/ULTSYM.1995.495722","DOIUrl":"https://doi.org/10.1109/ULTSYM.1995.495722","url":null,"abstract":"Time-of-flight measurements with point-like contact transducers have successfully been applied for the detection of anisotropy, and for in situ measurements of film thickness and temperature. This paper presents a new type of Hertzian-contact transducer of waveguiding structure operating in the MHz range. The transducer is composed of a fused quartz tube and a radially-polarized annular piezoelectric element bonded to one of its ends. The edge-bonded shear-wave transducer effectively excites a surface wave on the interior surface of the tube. A small bullet pin made of quartz is inserted and fixed on the other end of the tube to make a point contact and transmit the wave energy to a specimen to be inspected. Using a pair of these transducers, we have succeeded in the excitation and detection of surface acoustic waves as well as Lamb waves in the 3 MHz frequency range.","PeriodicalId":268177,"journal":{"name":"1995 IEEE Ultrasonics Symposium. Proceedings. An International Symposium","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116101962","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：