Pub Date : 1999-10-17DOI: 10.1109/ULTSYM.1999.849347
G. Martin
Transversely Coupled Resonator Filters (TCRFs) have become an important type of low-loss filters with narrow bandwidth. Their basic layout consists of two one-port resonators arranged acoustically in parallel. Therefore a mechanism that couples both original resonators with each other is necessary. In today's TCRFs, this coupling is implemented by the waveguide effect. A brief description of the historical background is given. The most important steps were MSC, IDT and U-path coupled resonator filters, strip, slot wave-guides and grating waveguides. In the nineties, modeling goes different ways. On the one hand, plane-wave parameters are used for calculating the properties of waveguide modes. To do this, the stack-matrix approach or a conventional eigenmode analysis is applied. On the other hand, the COM theory plays an important role. For this, the COM parameters for the two fundamental waveguide modes are determined experimentally and put into the TCRF analysis. In recent years, new design features were suggested for widening the bandwidth of TCRFs without changing the waveguide parameters. In this connection, the utilization of higher modes, the principle of combining waveguide and cavity modes and the waveguide coupling of resonators with different properties are considered in more detail. Modeling as well as experimental results are presented. Finally, the advantages and disadvantages of TCRFs are discussed.
{"title":"Transversely coupled resonator filters","authors":"G. Martin","doi":"10.1109/ULTSYM.1999.849347","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849347","url":null,"abstract":"Transversely Coupled Resonator Filters (TCRFs) have become an important type of low-loss filters with narrow bandwidth. Their basic layout consists of two one-port resonators arranged acoustically in parallel. Therefore a mechanism that couples both original resonators with each other is necessary. In today's TCRFs, this coupling is implemented by the waveguide effect. A brief description of the historical background is given. The most important steps were MSC, IDT and U-path coupled resonator filters, strip, slot wave-guides and grating waveguides. In the nineties, modeling goes different ways. On the one hand, plane-wave parameters are used for calculating the properties of waveguide modes. To do this, the stack-matrix approach or a conventional eigenmode analysis is applied. On the other hand, the COM theory plays an important role. For this, the COM parameters for the two fundamental waveguide modes are determined experimentally and put into the TCRF analysis. In recent years, new design features were suggested for widening the bandwidth of TCRFs without changing the waveguide parameters. In this connection, the utilization of higher modes, the principle of combining waveguide and cavity modes and the waveguide coupling of resonators with different properties are considered in more detail. Modeling as well as experimental results are presented. Finally, the advantages and disadvantages of TCRFs are discussed.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"7 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":"116530795","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.1999.849200
O. Oralkn, X. Jin, F. Degertekin, B. Khuri-Yakub
In this paper, a 400-/spl mu/m/spl times/400-/spl mu/m, 2-D capacitive micromachined ultrasonic transducer array element is experimentally characterized, and the results are found to be in agreement with theoretical predictions. As a receiver the transducer has a 1.8/spl times/10/sup -7/ nm//spl radic/Hz displacement sensitivity, and, as a transmitter, it produces 16.4 kPa/V of output pressure at the transducer surface at 3 MHz. The transducer also has more than 100% fractional bandwidth around 3 MHz, which makes it suitable for ultrasound imaging. The radiation pattern measurements indicate a 3-dB acceptance angle of /spl plusmn/35 degrees in agreement with the theoretical predictions.
{"title":"Simulation and experimental characterization of a 2-D, 3-MHz capacitive micromachined ultrasonic transducer (CMUT) array element","authors":"O. Oralkn, X. Jin, F. Degertekin, B. Khuri-Yakub","doi":"10.1109/ULTSYM.1999.849200","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849200","url":null,"abstract":"In this paper, a 400-/spl mu/m/spl times/400-/spl mu/m, 2-D capacitive micromachined ultrasonic transducer array element is experimentally characterized, and the results are found to be in agreement with theoretical predictions. As a receiver the transducer has a 1.8/spl times/10/sup -7/ nm//spl radic/Hz displacement sensitivity, and, as a transmitter, it produces 16.4 kPa/V of output pressure at the transducer surface at 3 MHz. The transducer also has more than 100% fractional bandwidth around 3 MHz, which makes it suitable for ultrasound imaging. The radiation pattern measurements indicate a 3-dB acceptance angle of /spl plusmn/35 degrees in agreement with the theoretical predictions.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"48 15 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":"122411388","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.1999.849516
D. Serge, R. Pascal, I. Jean-Louis
The characteristics of the acoustic resonances of an elastic shell are obtained via the Fourier transform of the whole scattered signal and the inverse Fourier transform of a narrow frequency band in the vicinity of a resonance frequency.
{"title":"Measurement of acoustic resonance width via the inverse Fourier transform of the Breit-Wigner form","authors":"D. Serge, R. Pascal, I. Jean-Louis","doi":"10.1109/ULTSYM.1999.849516","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849516","url":null,"abstract":"The characteristics of the acoustic resonances of an elastic shell are obtained via the Fourier transform of the whole scattered signal and the inverse Fourier transform of a narrow frequency band in the vicinity of a resonance frequency.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"1 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":"122549838","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.1999.849388
A. Ronnekleiv
A full wave PSAW waveguide theory is used to calculate PSAW waveguide propagation properties on orientations of quartz, lithium tantalate, and lithium niobate. Only structures where the wave velocities nominally inhibit sideways radiation from the guide, proper waveguides, are investigated. Curves showing losses versus waveguide width are given for several surface conditions outside the waveguide. Even for proper waveguides the losses due to bulk wave excitation at the edges of the guides may be substantial, depending on the mechanical and electrical loading of the two adjoining surfaces. Especially in quartz this effect is pronounced, and total loss differences of up to a factor of ten are found for waveguides only differing in the mechanical loading outside the guide. The losses are in general found to be too high for use of PSAW in waveguide coupled filters. For STW on quartz it is however not far from being possible. Losses due to coupling to PSAW or the Rayleigh wave propagating at a large angle to the guide, are not found to be a problem.
{"title":"Numerical investigation of PSAW propagation in waveguides","authors":"A. Ronnekleiv","doi":"10.1109/ULTSYM.1999.849388","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849388","url":null,"abstract":"A full wave PSAW waveguide theory is used to calculate PSAW waveguide propagation properties on orientations of quartz, lithium tantalate, and lithium niobate. Only structures where the wave velocities nominally inhibit sideways radiation from the guide, proper waveguides, are investigated. Curves showing losses versus waveguide width are given for several surface conditions outside the waveguide. Even for proper waveguides the losses due to bulk wave excitation at the edges of the guides may be substantial, depending on the mechanical and electrical loading of the two adjoining surfaces. Especially in quartz this effect is pronounced, and total loss differences of up to a factor of ten are found for waveguides only differing in the mechanical loading outside the guide. The losses are in general found to be too high for use of PSAW in waveguide coupled filters. For STW on quartz it is however not far from being possible. Losses due to coupling to PSAW or the Rayleigh wave propagating at a large angle to the guide, are not found to be a problem.","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":"122966342","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.1999.849216
E. Light, J. Fiering, P. Hultman, W. Lee, S.W. Smith
The authors have previously described 2-D array transducers with up to several thousand elements operating at frequencies between 2.5 and 5.0 MHz for real time volumetric imaging. Lately, there has been interest in developing catheter based intracardiac imaging systems to aid in the precise tracking of anatomical features and intracardiac devices for improved diagnoses and therapies. The authors constructed several arrays for real time intracardiac volumetric imaging based upon 2 different designs; a 13/spl times/11=143 element 5.0 MHz 2-D array for side scanning applications, and a 10/spl times/10=100 element 7.0 MHz 2-D array for side scanning applications. The 5.0 MHz array fits into a 12 French (3.8 mm OD) catheter and the 7.0 MHz transducer is designed to fit into a 9 French (2.9 mm OD) catheter. The authors also constructed 2 transducers for transthoracic imaging; a 40/spl times/40 5.0 MHz 2-D array, and a 40/spl times/40 7.0 MHz 2-D array. The -6 dB fractional bandwidths for the transducers varied from 27% to 67%. All the transducers were constructed on a 6 layer polyimide interconnect. Both transthoracic and intracardiac volumetric images of ultrasound phantoms and animal models have been obtained using the Duke University real time volumetric imaging system which is capable of generating multiple planes at any desired angle and depth within a pyramidal volume.
作者之前描述了多达数千个元件的二维阵列换能器，工作频率在2.5到5.0 MHz之间，用于实时体积成像。最近，人们对开发基于导管的心内成像系统感兴趣，以帮助精确跟踪解剖特征和心内装置，以改进诊断和治疗。作者基于两种不同的设计构建了几种实时心内容积成像阵列;一个13/spl次/11=143单元5.0 MHz二维阵列用于侧面扫描应用，一个10/spl次/10=100单元7.0 MHz二维阵列用于侧面扫描应用。5.0 MHz阵列适合12 French (3.8 mm OD)导管，7.0 MHz换能器设计适合9 French (2.9 mm OD)导管。作者还构建了2个经胸成像传感器;一个40/spl倍/40 5.0 MHz二维阵列和一个40/spl倍/40 7.0 MHz二维阵列。换能器的- 6db分数带宽从27%到67%不等。所有的换能器都构建在6层聚酰亚胺互连上。使用杜克大学实时体积成像系统，可以在锥体体积内产生任意角度和深度的多个平面，从而获得超声模型和动物模型的经胸和心内体积图像。
{"title":"Update of two dimensional arrays for real time volumetric and real time intracardiac imaging","authors":"E. Light, J. Fiering, P. Hultman, W. Lee, S.W. Smith","doi":"10.1109/ULTSYM.1999.849216","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849216","url":null,"abstract":"The authors have previously described 2-D array transducers with up to several thousand elements operating at frequencies between 2.5 and 5.0 MHz for real time volumetric imaging. Lately, there has been interest in developing catheter based intracardiac imaging systems to aid in the precise tracking of anatomical features and intracardiac devices for improved diagnoses and therapies. The authors constructed several arrays for real time intracardiac volumetric imaging based upon 2 different designs; a 13/spl times/11=143 element 5.0 MHz 2-D array for side scanning applications, and a 10/spl times/10=100 element 7.0 MHz 2-D array for side scanning applications. The 5.0 MHz array fits into a 12 French (3.8 mm OD) catheter and the 7.0 MHz transducer is designed to fit into a 9 French (2.9 mm OD) catheter. The authors also constructed 2 transducers for transthoracic imaging; a 40/spl times/40 5.0 MHz 2-D array, and a 40/spl times/40 7.0 MHz 2-D array. The -6 dB fractional bandwidths for the transducers varied from 27% to 67%. All the transducers were constructed on a 6 layer polyimide interconnect. Both transthoracic and intracardiac volumetric images of ultrasound phantoms and animal models have been obtained using the Duke University real time volumetric imaging system which is capable of generating multiple planes at any desired angle and depth within a pyramidal volume.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"20 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":"122993907","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.1999.849336
S. Podell, Brent Golec, Rolf Lohnnann
In vitro acoustic studies generally assume that known and reproducible quantities of contrast media are being evaluated, without need for agent retesting after dilution and handling. This assumption is incorrect, because duration of ultrasound contrast is substantially reduced by dilution of encapsulated, gas-filled agents into gas-poor solutions. Contrast agent persistence is enhanced and diffusive gas loss is slowed, but not eliminated, by filling microspheres with core gases having lower aqueous solubility. Since diffusive gas loss promotes safe elimination of gas bubbles in vivo, it is a desirable property that may prove unavoidable for commercial contrast agents. For non-encapsulated contrast agents containing emulsified perfluorocarbon liquids, exposure to threshold levels of ultrasound energy increased the dose of available contrast, by causing superheated liquid droplets to boil and form new microbubbles. This sudden activation threshold was not observed in encapsulated microsphere formulations, where the same perfluorocarbon was converted to vapor phase prior to insonation. These findings show that effective contrast agent doses can rapidly increase or decrease under conditions commonly used for in vitro acoustic testing. To avoid potential misinterpretation of experimental results, the effects of ultrasound independent factors on contrast agent stability need to be carefully considered.
{"title":"Measuring the effects of ultrasound on contrast agents","authors":"S. Podell, Brent Golec, Rolf Lohnnann","doi":"10.1109/ULTSYM.1999.849336","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849336","url":null,"abstract":"In vitro acoustic studies generally assume that known and reproducible quantities of contrast media are being evaluated, without need for agent retesting after dilution and handling. This assumption is incorrect, because duration of ultrasound contrast is substantially reduced by dilution of encapsulated, gas-filled agents into gas-poor solutions. Contrast agent persistence is enhanced and diffusive gas loss is slowed, but not eliminated, by filling microspheres with core gases having lower aqueous solubility. Since diffusive gas loss promotes safe elimination of gas bubbles in vivo, it is a desirable property that may prove unavoidable for commercial contrast agents. For non-encapsulated contrast agents containing emulsified perfluorocarbon liquids, exposure to threshold levels of ultrasound energy increased the dose of available contrast, by causing superheated liquid droplets to boil and form new microbubbles. This sudden activation threshold was not observed in encapsulated microsphere formulations, where the same perfluorocarbon was converted to vapor phase prior to insonation. These findings show that effective contrast agent doses can rapidly increase or decrease under conditions commonly used for in vitro acoustic testing. To avoid potential misinterpretation of experimental results, the effects of ultrasound independent factors on contrast agent stability need to be carefully considered.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"20 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":"117033957","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.1999.849414
Y. Yamamoto, H. Kawahara, N. Sakairi, Y. Takahashi, R. Kajihara, T. Tsuda, S. Yoshimoto
Mobile market in Japan is rapidly growing as well as Europe, North America and other countries. The major mobile phone system in Japan are PDC (Personal Digital Cellular) and PHS (Personal Handy Phone System), and the new service called cdmaOneTM has just started since last year. And W-CDMA system is expected to start on 2001 as new generation of mobile phone system in Japan. Since these system utilize different communication method, the specifications of the intermediate frequency (IF) filters for the systems are totally different from each other and from that of European GSM and north American AMPS. In addition, tiny and light mobile phone products are preferable in Japanese market, the size of these IF SAW filters are shrinking year by year. In this paper the technical outlines of IF SAW filter for mobile phones in Japanese market and their recent trends will be described, and also their future trend will be discussed.
日本、欧洲、北美和其他国家的手机市场发展迅速。日本的主要移动电话系统是PDC (Personal Digital Cellular)和PHS (Personal Handy phone system)，而新服务cdmaOneTM从去年开始才开始运营。而W-CDMA系统将作为日本的新一代移动电话系统，从2001年开始投入使用。由于这些系统采用不同的通信方式，系统的中频滤波器的规格与欧洲GSM和北美AMPS完全不同。此外，在日本市场上，小而轻的手机产品更受欢迎，这些中频SAW滤波器的尺寸正在逐年缩小。本文介绍了日本市场上手机用中频SAW滤波器的技术概况和最新发展趋势，并对其未来发展趋势进行了讨论。
{"title":"Intermediate frequency SAW filters for mobile phone application in Japanese markets","authors":"Y. Yamamoto, H. Kawahara, N. Sakairi, Y. Takahashi, R. Kajihara, T. Tsuda, S. Yoshimoto","doi":"10.1109/ULTSYM.1999.849414","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849414","url":null,"abstract":"Mobile market in Japan is rapidly growing as well as Europe, North America and other countries. The major mobile phone system in Japan are PDC (Personal Digital Cellular) and PHS (Personal Handy Phone System), and the new service called cdmaOneTM has just started since last year. And W-CDMA system is expected to start on 2001 as new generation of mobile phone system in Japan. Since these system utilize different communication method, the specifications of the intermediate frequency (IF) filters for the systems are totally different from each other and from that of European GSM and north American AMPS. In addition, tiny and light mobile phone products are preferable in Japanese market, the size of these IF SAW filters are shrinking year by year. In this paper the technical outlines of IF SAW filter for mobile phones in Japanese market and their recent trends will be described, and also their future trend will be discussed.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"27 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":"129520331","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.1999.849478
A. Fukuyama, M. Iwamoto, Y. Akashi, T. Ikari, M. Suemitsu
The temperature variation of the piezoelectric photoacoustic (PPA) signal intensity of semi-insulating (SI) GaAs from 20 to 150 K was measured. Four distinctive peaks at 50, 70, 110 and 125 K were observed. From the theoretical analysis based on the rate equations of electrons in the conduction band and several deep levels, we concluded that two distinctive peaks at 70 and 125 K were due to the nonradiative recombination of photoexcited electrons from EL2 to EL6+ and EL10+/EL11+ deep levels, respectively. Deep levels with extremely low concentration (1012-1015 cm-3) were clearly detected in SI-GaAs by using PPA method for the first time.
{"title":"New aspects for investigation of carrier transition through deep levels in GaAs by a piezoelectric photoacoustic technique","authors":"A. Fukuyama, M. Iwamoto, Y. Akashi, T. Ikari, M. Suemitsu","doi":"10.1109/ULTSYM.1999.849478","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849478","url":null,"abstract":"The temperature variation of the piezoelectric photoacoustic (PPA) signal intensity of semi-insulating (SI) GaAs from 20 to 150 K was measured. Four distinctive peaks at 50, 70, 110 and 125 K were observed. From the theoretical analysis based on the rate equations of electrons in the conduction band and several deep levels, we concluded that two distinctive peaks at 70 and 125 K were due to the nonradiative recombination of photoexcited electrons from EL2 to EL6+ and EL10+/EL11+ deep levels, respectively. Deep levels with extremely low concentration (1012-1015 cm-3) were clearly detected in SI-GaAs by using PPA method for the first time.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"101 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":"128776679","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.1999.849320
L. Hoff, T. Johansen
Presents a nonlinear model for the response of shell-encapsulated gas bubbles to an ultrasound pulse. Values for the viscoelastic properties of the shell were estimated from ultrasound measurements at low amplitude. Results from simulations were compared with experiments. Ultrasound pulses were transmitted with a 1 MHz transducer into samples of Sonazoid. Pressure amplitudes were varied between 20 and 500 kPa. In the received echoes, frequency components up to the 9th harmonic of the transmit frequency were detected. Good agreement was found between the experimental results and predictions from the theory. Theories based on gas-bubbles without shell give poor agreement between theoretical and experimental results.
{"title":"Nonlinear scatter from Sonazoid","authors":"L. Hoff, T. Johansen","doi":"10.1109/ULTSYM.1999.849320","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849320","url":null,"abstract":"Presents a nonlinear model for the response of shell-encapsulated gas bubbles to an ultrasound pulse. Values for the viscoelastic properties of the shell were estimated from ultrasound measurements at low amplitude. Results from simulations were compared with experiments. Ultrasound pulses were transmitted with a 1 MHz transducer into samples of Sonazoid. Pressure amplitudes were varied between 20 and 500 kPa. In the received echoes, frequency components up to the 9th harmonic of the transmit frequency were detected. Good agreement was found between the experimental results and predictions from the theory. Theories based on gas-bubbles without shell give poor agreement between theoretical and experimental results.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"11 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":"129262945","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.1999.849383
A. Baghai-Wadji
Scattering of transverse-electric or magnetic plane waves on infinitely long and ideally conductive strips and bends has been treated thoroughly quite long ago. Also, scattering of electromagnetic waves on rectangular bent plates has been the subject of research. Furthermore, wires in the vicinity of plates or bends, and wires attached to these structures have been investigated. The analyses have been performed by applying Harrington's method of moments (MoM). However, the design of even “canonical structures” can become quite challenging both in terms of computational resources and the accuracy: The calculations have to be repeated when any of problems' parameters e.g. frequency, bent angle, dimensions of the strips or plates or wires changes. In this paper we reconsider these problems for two reasons. First, they well may serve as models for 2D and 3D cross-talk modeling in acoustic devices, and there have great practical significance. Second, we treat these problems to point out the shortcomings of the conventional MoM, and to sketch how the newly proposed Fast-MoM technique eliminates them. In previous works we had applied the Fast-MoM to vector fields in flat surface problems, and to scalar fields in geometries with perpendicular boundaries. The present discussion shows how these geometric restrictions can be removed by introducing a local coordinate system.
{"title":"2D and 3D models for the cross-talk modeling in acoustic devices: a fast-MoM approach","authors":"A. Baghai-Wadji","doi":"10.1109/ULTSYM.1999.849383","DOIUrl":"https://doi.org/10.1109/ULTSYM.1999.849383","url":null,"abstract":"Scattering of transverse-electric or magnetic plane waves on infinitely long and ideally conductive strips and bends has been treated thoroughly quite long ago. Also, scattering of electromagnetic waves on rectangular bent plates has been the subject of research. Furthermore, wires in the vicinity of plates or bends, and wires attached to these structures have been investigated. The analyses have been performed by applying Harrington's method of moments (MoM). However, the design of even “canonical structures” can become quite challenging both in terms of computational resources and the accuracy: The calculations have to be repeated when any of problems' parameters e.g. frequency, bent angle, dimensions of the strips or plates or wires changes. In this paper we reconsider these problems for two reasons. First, they well may serve as models for 2D and 3D cross-talk modeling in acoustic devices, and there have great practical significance. Second, we treat these problems to point out the shortcomings of the conventional MoM, and to sketch how the newly proposed Fast-MoM technique eliminates them. In previous works we had applied the Fast-MoM to vector fields in flat surface problems, and to scalar fields in geometries with perpendicular boundaries. The present discussion shows how these geometric restrictions can be removed by introducing a local coordinate system.","PeriodicalId":339424,"journal":{"name":"1999 IEEE Ultrasonics Symposium. Proceedings. International Symposium (Cat. No.99CH37027)","volume":"25 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":"129543146","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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