Pub Date : 2002-10-08DOI: 10.1109/ULTSYM.2002.1193402
Chun-Yun Jian, S. Beaudin
This paper introduces a new type of SPUDT structure, which enables the design of SAW filters or delay-lines up into the 2 GHz range. The structure consists of two groups of spatially harmonic transducers e.g. Se=5 (+ + - + -) or Se=8 (+ + - + - - + -) and one group of reflectors positioned between the two groups of harmonic transducers. In the paper, the general operating principle of the new SPUDT is discussed. To confirm this new technique, a slanted type SAW filter using the new SPUDT structure with central frequency of 2.14 GHz was designed and fabricated. The directionality of this new SPUDT structure has been demonstrated by measurement.
{"title":"A new type SPUDT SAW for use in high frequency around 2 GHz","authors":"Chun-Yun Jian, S. Beaudin","doi":"10.1109/ULTSYM.2002.1193402","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1193402","url":null,"abstract":"This paper introduces a new type of SPUDT structure, which enables the design of SAW filters or delay-lines up into the 2 GHz range. The structure consists of two groups of spatially harmonic transducers e.g. Se=5 (+ + - + -) or Se=8 (+ + - + - - + -) and one group of reflectors positioned between the two groups of harmonic transducers. In the paper, the general operating principle of the new SPUDT is discussed. To confirm this new technique, a slanted type SAW filter using the new SPUDT structure with central frequency of 2.14 GHz was designed and fabricated. The directionality of this new SPUDT structure has been demonstrated by measurement.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"549 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":"127958146","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.2002.1192543
F. Jenson, F. Padilla, P. Laugier
The goal of this study is to propose a model for the ultrasonic frequency-dependent backscatter coefficient in cancellous bone. A weak scattering model is used. It allows us to address the inverse problem and to predict the mean trabecular thickness. The backscatter coefficient is expressed in terms of an autocorrelation function of the medium. Comparison is made with experimental data for 19 specimens and for frequency ranging from 0.4 to 1.2 MHz. For each specimen a non-linear regression is performed and the mean trabecular thickness is estimated. Experimental data and theoretical predictions are averaged over the 19 specimens. A good agreement between experimental data and predictions was found for both the magnitude and the frequency-dependence of the backscatter coefficient. We also found a good agreement between the experimental mean trabecular thickness (Tb.Th=130/spl plusmn/6.5 /spl mu/m) derived from the analysis of bone 3-D micro-architecture using high resolution micro-tomography and theoretical predictions (d/sub Gauss/ = 140/spl plusmn/10 /spl mu/m, d/sub exponential/=153/spl plusmn/12.5 /spl mu/m). These results open interesting prospects for the estimation of the mean trabecular thickness from in vivo measurements.
{"title":"Prediction of frequency-dependent ultrasonic backscatter in cancellous bone using statistical weak scattering model","authors":"F. Jenson, F. Padilla, P. Laugier","doi":"10.1109/ULTSYM.2002.1192543","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1192543","url":null,"abstract":"The goal of this study is to propose a model for the ultrasonic frequency-dependent backscatter coefficient in cancellous bone. A weak scattering model is used. It allows us to address the inverse problem and to predict the mean trabecular thickness. The backscatter coefficient is expressed in terms of an autocorrelation function of the medium. Comparison is made with experimental data for 19 specimens and for frequency ranging from 0.4 to 1.2 MHz. For each specimen a non-linear regression is performed and the mean trabecular thickness is estimated. Experimental data and theoretical predictions are averaged over the 19 specimens. A good agreement between experimental data and predictions was found for both the magnitude and the frequency-dependence of the backscatter coefficient. We also found a good agreement between the experimental mean trabecular thickness (Tb.Th=130/spl plusmn/6.5 /spl mu/m) derived from the analysis of bone 3-D micro-architecture using high resolution micro-tomography and theoretical predictions (d/sub Gauss/ = 140/spl plusmn/10 /spl mu/m, d/sub exponential/=153/spl plusmn/12.5 /spl mu/m). These results open interesting prospects for the estimation of the mean trabecular thickness from in vivo measurements.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"24 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":"115769286","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.2002.1192558
A. Acquafresca, E. Biagi, S. Cerbai, L. Masotti
Recent progresses in opto-acoustics let us foresee the possibility to realize a strongly miniaturized transducer, characterized by high cutoff frequency, wide bandwidth, high electromagnetic compatibility and no electrical wiring. This transducer is constituted by two optical fibers: a first fiber, with a heavily absorbing film on its extremity generates broad-band ultrasounds. Another fiber, with a Fabry-Perot cavity mounted on its tip, detects ultrasonic echoes through optic interferometry. Such a transducer may result greatly useful for diagnostic applications, allowing for higher echographic resolution and microstructural tissue characterization. In addition, the strong miniaturization would allow its insertion into human body for direct investigation of focal lesions with minimal invasivity. Thus, a path toward "virtual biopsy" may be traced.
{"title":"Towards virtual biopsy through an all fiber optic ultrasonic miniaturized transducer: a proposal","authors":"A. Acquafresca, E. Biagi, S. Cerbai, L. Masotti","doi":"10.1109/ULTSYM.2002.1192558","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1192558","url":null,"abstract":"Recent progresses in opto-acoustics let us foresee the possibility to realize a strongly miniaturized transducer, characterized by high cutoff frequency, wide bandwidth, high electromagnetic compatibility and no electrical wiring. This transducer is constituted by two optical fibers: a first fiber, with a heavily absorbing film on its extremity generates broad-band ultrasounds. Another fiber, with a Fabry-Perot cavity mounted on its tip, detects ultrasonic echoes through optic interferometry. Such a transducer may result greatly useful for diagnostic applications, allowing for higher echographic resolution and microstructural tissue characterization. In addition, the strong miniaturization would allow its insertion into human body for direct investigation of focal lesions with minimal invasivity. Thus, a path toward \"virtual biopsy\" may be traced.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"43 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":"132225200","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.2002.1192642
F. J. de Ana, M. O’Donnell
Vibration of piezoelectric elements after electrical excitation creates ringdown artifacts in ultrasound images close to the transducer surface. For intraluminal applications, high quality images are often needed at depths close to the catheter surface. Consequently, ringdown artifacts pose a serious problem for intraluminal circumferential arrays. A current method to reduce these artificial echoes subtracts a precalibrated ringdown signal from each frame in a data set. The dynamic nature of the ringdown artifact, however, reduces the effectiveness of this subtraction algorithm with time following data collection. The ringdown signal has very distinctive characteristics, especially in the near field azimuthal spectrum. An in-depth study of those characteristics presents new alternatives to minimize ringdown artifacts. Using a set of depth-dependent azimuthal filters, we present a method to significantly reduce ringdown artifacts while minimally affecting the real signal. Rubber phantoms with embedded graphite particles were imaged close to the transducer surface to study potential improvements obtained with the azimuthal filters. Results show a reduction of the ringdown signal by at least 10 dB, while increasing the dynamic range between the real signal and the ringdown from 2 dB to 15 dB. The combination of azimuthal filtering with ringdown subtraction can greatly enhance contrast at ranges close to the transducer surface.
{"title":"Ringdown reduction for an intraluminal ultrasound array using depth-dependent azimuthal filters","authors":"F. J. de Ana, M. O’Donnell","doi":"10.1109/ULTSYM.2002.1192642","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1192642","url":null,"abstract":"Vibration of piezoelectric elements after electrical excitation creates ringdown artifacts in ultrasound images close to the transducer surface. For intraluminal applications, high quality images are often needed at depths close to the catheter surface. Consequently, ringdown artifacts pose a serious problem for intraluminal circumferential arrays. A current method to reduce these artificial echoes subtracts a precalibrated ringdown signal from each frame in a data set. The dynamic nature of the ringdown artifact, however, reduces the effectiveness of this subtraction algorithm with time following data collection. The ringdown signal has very distinctive characteristics, especially in the near field azimuthal spectrum. An in-depth study of those characteristics presents new alternatives to minimize ringdown artifacts. Using a set of depth-dependent azimuthal filters, we present a method to significantly reduce ringdown artifacts while minimally affecting the real signal. Rubber phantoms with embedded graphite particles were imaged close to the transducer surface to study potential improvements obtained with the azimuthal filters. Results show a reduction of the ringdown signal by at least 10 dB, while increasing the dynamic range between the real signal and the ringdown from 2 dB to 15 dB. The combination of azimuthal filtering with ringdown subtraction can greatly enhance contrast at ranges close to the transducer surface.","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":"129981483","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.2002.1193425
M. Pereira da Cunha, D. Malocha, D. Puccio, J. Thiele, T. Pollard
This paper reports predicted and measured properties of the pure shear horizontal (SH) mode for the LGX family of crystals, which includes langasite (LGS), langanite (LGN), and langatate (LGT). Our results show high electromechanical coupling and zero temperature coefficient of delay (TCD) along LGX Euler angles (0/spl deg/, /spl theta/, 90/spl deg/), /spl theta/ between 10/spl deg/ and 25/spl deg/, with penetration depths which are comparable to SAW devices. In particular along LGT (0/spl deg/, 13.5/spl deg/, 90/spl deg/), experimental results are disclosed with resonators and delay line structures which verify the high electromechanical coupling (0.8%), about 10 times stronger than the 36/spl deg/ Y rotated quartz SH orientation, and zero TCD around 140 *C. The penetration depth of 7 wavelengths is about eight times shallower than 36/spl deg/ Y quartz. The phase velocity of 2660 m/s is within 0.2% of the calculated value, which is about 55% below the phase velocity of 36/spl deg/ Y quartz, thus leading to smaller Surface Transverse Wave (STW) devices. With such positive predicted and measured coupling and propagation characteristics, these orientations suggest the fabrication of high coupling, zero TCD, and smaller STW devices for liquid sensor, filtering, and frequency control applications.
{"title":"High coupling, zero TCD SH wave on LGX","authors":"M. Pereira da Cunha, D. Malocha, D. Puccio, J. Thiele, T. Pollard","doi":"10.1109/ULTSYM.2002.1193425","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1193425","url":null,"abstract":"This paper reports predicted and measured properties of the pure shear horizontal (SH) mode for the LGX family of crystals, which includes langasite (LGS), langanite (LGN), and langatate (LGT). Our results show high electromechanical coupling and zero temperature coefficient of delay (TCD) along LGX Euler angles (0/spl deg/, /spl theta/, 90/spl deg/), /spl theta/ between 10/spl deg/ and 25/spl deg/, with penetration depths which are comparable to SAW devices. In particular along LGT (0/spl deg/, 13.5/spl deg/, 90/spl deg/), experimental results are disclosed with resonators and delay line structures which verify the high electromechanical coupling (0.8%), about 10 times stronger than the 36/spl deg/ Y rotated quartz SH orientation, and zero TCD around 140 *C. The penetration depth of 7 wavelengths is about eight times shallower than 36/spl deg/ Y quartz. The phase velocity of 2660 m/s is within 0.2% of the calculated value, which is about 55% below the phase velocity of 36/spl deg/ Y quartz, thus leading to smaller Surface Transverse Wave (STW) devices. With such positive predicted and measured coupling and propagation characteristics, these orientations suggest the fabrication of high coupling, zero TCD, and smaller STW devices for liquid sensor, filtering, and frequency control applications.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"88 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":"134505087","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.2002.1193524
N. Nishiwaki, S. Hori, N. Otsuki, S. Zhou
In this paper, a state of vibration-welded joints of thermoplastics has been nondestructively measured using an ultrasonic technique during the vibration welding process. As the results, not only the state but also the tensile strength of the vibration-welded joints can be evaluated during the welding process.
{"title":"Measurement of behavior at welding resin parts using ultrasonic technique","authors":"N. Nishiwaki, S. Hori, N. Otsuki, S. Zhou","doi":"10.1109/ULTSYM.2002.1193524","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1193524","url":null,"abstract":"In this paper, a state of vibration-welded joints of thermoplastics has been nondestructively measured using an ultrasonic technique during the vibration welding process. As the results, not only the state but also the tensile strength of the vibration-welded joints can be evaluated during the welding process.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"20 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":"131797404","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.2002.1192593
L. Nock, S. Brunke, H. Jiang, J. J. Mai, G. Trahey, P. von Behren
Under a contract with the National Cancer Institute, we have developed an ultrasound research interface on a commercial scanner. The user can access and control a variety of scanner parameters which are not directly accessible through the clinical user interface, but which are vital to the success of potential scientific experiments. User-selectable parameters include ensemble or packet size, framerate, and receive aperture growth enable/disable. The research interface stores digitally beam formed RF (radio frequency) data in a format suitable for post processing for research. We present preliminary results demonstrating the interface's functionality and utility in several areas of research. As an example, we configured the research interface to collect raw RF data using phase inversion methods. The data was processed in two different ways, to emphasize the tissue signal using subtraction and filtering of inverted-phase signals and to emphasize the contrast agent signal using addition and filtering of inverted-phase signals.
{"title":"A new medical ultrasound research interface","authors":"L. Nock, S. Brunke, H. Jiang, J. J. Mai, G. Trahey, P. von Behren","doi":"10.1109/ULTSYM.2002.1192593","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1192593","url":null,"abstract":"Under a contract with the National Cancer Institute, we have developed an ultrasound research interface on a commercial scanner. The user can access and control a variety of scanner parameters which are not directly accessible through the clinical user interface, but which are vital to the success of potential scientific experiments. User-selectable parameters include ensemble or packet size, framerate, and receive aperture growth enable/disable. The research interface stores digitally beam formed RF (radio frequency) data in a format suitable for post processing for research. We present preliminary results demonstrating the interface's functionality and utility in several areas of research. As an example, we configured the research interface to collect raw RF data using phase inversion methods. The data was processed in two different ways, to emphasize the tissue signal using subtraction and filtering of inverted-phase signals and to emphasize the contrast agent signal using addition and filtering of inverted-phase signals.","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":"131810333","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.2002.1193459
O. Kripfgans, P. Carson, J. Fowlkes
It has been observed in the past that micrometer sized droplets can be vaporized into gas bubbles by the application of diagnostic ultrasound. This paper will discuss the possible underlying mechanism of acoustic droplet vaporization (ADV) including acoustic cavitation, acoustic heating, shape oscillations during acoustic irradiation, and hydrodynamic cavitation. Experiments were performed on droplet emulsions as well as on single droplets. The vaporization of emulsions was quantified based on gas bubbles generated in a flow tube using a 10 MHz linear imaging army. Single droplets were monitored optically under a microscope and a high speed video system. The frequency dependence of ADV as well as trials with degassed water (40% of saturation) imply that acoustic cavitation is not the mechanism for ADV. Acoustic heating was investigated by exposing the droplet emulsion to repetitive tone bursts (50 Hz to 5 kHz). No significant change in pressure threshold for ADV was observed, however the yield of gas bubbles was used to calculate the single pulse conversion efficiency of ADV to 26%. Droplet shape oscillations causing a non-uniform Laplace pressure, were found to be 15% or less of the droplet diameter. They could be observed at the beginning and at the end of the acoustic irradiation. Observed was a dipole-type motion (1.3 /spl mu/m amplitude) of irradiated droplets as well as the spot-like onset of vaporization on the axis of oscillation close to a pole of the droplet. It is concluded that because of the high Reynolds number during ADV (4-5/spl times/10/sup 5/), the mechanism of vaporization might be based on hydrodynamic effects.
{"title":"On the mechanism of acoustic droplet vaporization","authors":"O. Kripfgans, P. Carson, J. Fowlkes","doi":"10.1109/ULTSYM.2002.1193459","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1193459","url":null,"abstract":"It has been observed in the past that micrometer sized droplets can be vaporized into gas bubbles by the application of diagnostic ultrasound. This paper will discuss the possible underlying mechanism of acoustic droplet vaporization (ADV) including acoustic cavitation, acoustic heating, shape oscillations during acoustic irradiation, and hydrodynamic cavitation. Experiments were performed on droplet emulsions as well as on single droplets. The vaporization of emulsions was quantified based on gas bubbles generated in a flow tube using a 10 MHz linear imaging army. Single droplets were monitored optically under a microscope and a high speed video system. The frequency dependence of ADV as well as trials with degassed water (40% of saturation) imply that acoustic cavitation is not the mechanism for ADV. Acoustic heating was investigated by exposing the droplet emulsion to repetitive tone bursts (50 Hz to 5 kHz). No significant change in pressure threshold for ADV was observed, however the yield of gas bubbles was used to calculate the single pulse conversion efficiency of ADV to 26%. Droplet shape oscillations causing a non-uniform Laplace pressure, were found to be 15% or less of the droplet diameter. They could be observed at the beginning and at the end of the acoustic irradiation. Observed was a dipole-type motion (1.3 /spl mu/m amplitude) of irradiated droplets as well as the spot-like onset of vaporization on the axis of oscillation close to a pole of the droplet. It is concluded that because of the high Reynolds number during ADV (4-5/spl times/10/sup 5/), the mechanism of vaporization might be based on hydrodynamic effects.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"105 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":"127556797","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.2002.1192529
T. Dreyer, R.E. Riedlinger
A simulation procedure is presented to calculate the focal ultrasound pressure pulse from the driving voltage of a piezoelectric composite transducer or to calculate the required voltage from a given focal pressure pulse. The description of the transducer system including the driving circuit is done by linear systems theory. A transducer transfer function is derived by transient finite element simulations of the transducer structure. Focusing is assumed to be linear, which is valid for small amplitudes. Measurements validate the model.
{"title":"Combination of finite element simulations and linear systems theory for pulse shaping of piezoelectric transducers used in therapy","authors":"T. Dreyer, R.E. Riedlinger","doi":"10.1109/ULTSYM.2002.1192529","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1192529","url":null,"abstract":"A simulation procedure is presented to calculate the focal ultrasound pressure pulse from the driving voltage of a piezoelectric composite transducer or to calculate the required voltage from a given focal pressure pulse. The description of the transducer system including the driving circuit is done by linear systems theory. A transducer transfer function is derived by transient finite element simulations of the transducer structure. Focusing is assumed to be linear, which is valid for small amplitudes. Measurements validate the model.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"11 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":"132932166","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.2002.1193365
Susumu Yoshimoto, Yasushi Yamamoto, Y. Takahashi, Eiichi Otsuka
In recent years, multi-band RF SAW filters for mobile phone are strongly required. In this work, as the example of multi-band SAW filters, we report PDC triple-band SAW filter and EGSM /DCS dual-band balanced SAW filter using surface mount plastic package. These filters are encapsulated in plastic package and they are made by our new plastic molding technology. The plastic package has advantages of lightweight low material cost and low assembly cost. To integrate plural filters to one chip, we refined the conventional lift-off method. The method can realize easy fabrication of SAW chip for multi-band filter We utilized 36Y-X LiTaO/sub 3/ for substrates for the filter. The electrode structure of each filter is longitudinal-mode resonator filter With regards to PDC triple-band filter, we achieved typical insertion loss of 2.0 dB / 2.1 dB / 2.2 dB with bandwidth of 33 MHz / 15 MHz / 24 MHz for 800 MHz (called CD-band) / 800 MHz (called A-band) / 1.5 GHz, respectively, with excellent high rejection levels. And for another application of the plastic package, we developed EGSM/DCS Rx dual-band balanced SAW filter. We achieved insertion loss of 2.2 dB / 3.0 dB for EGSM and DCS filter, respectively, with good amplitude and phase balance. We could realize multi-band SAW filters using the plastic package and could confirm its usability for SAW devices.
{"title":"Multi-band RF SAW filter for mobile phone using surface mount plastic package","authors":"Susumu Yoshimoto, Yasushi Yamamoto, Y. Takahashi, Eiichi Otsuka","doi":"10.1109/ULTSYM.2002.1193365","DOIUrl":"https://doi.org/10.1109/ULTSYM.2002.1193365","url":null,"abstract":"In recent years, multi-band RF SAW filters for mobile phone are strongly required. In this work, as the example of multi-band SAW filters, we report PDC triple-band SAW filter and EGSM /DCS dual-band balanced SAW filter using surface mount plastic package. These filters are encapsulated in plastic package and they are made by our new plastic molding technology. The plastic package has advantages of lightweight low material cost and low assembly cost. To integrate plural filters to one chip, we refined the conventional lift-off method. The method can realize easy fabrication of SAW chip for multi-band filter We utilized 36Y-X LiTaO/sub 3/ for substrates for the filter. The electrode structure of each filter is longitudinal-mode resonator filter With regards to PDC triple-band filter, we achieved typical insertion loss of 2.0 dB / 2.1 dB / 2.2 dB with bandwidth of 33 MHz / 15 MHz / 24 MHz for 800 MHz (called CD-band) / 800 MHz (called A-band) / 1.5 GHz, respectively, with excellent high rejection levels. And for another application of the plastic package, we developed EGSM/DCS Rx dual-band balanced SAW filter. We achieved insertion loss of 2.2 dB / 3.0 dB for EGSM and DCS filter, respectively, with good amplitude and phase balance. We could realize multi-band SAW filters using the plastic package and could confirm its usability for SAW devices.","PeriodicalId":378705,"journal":{"name":"2002 IEEE Ultrasonics Symposium, 2002. Proceedings.","volume":"105 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":"133155460","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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