Pub Date : 2006-10-01DOI: 10.1109/DIPED.2006.314324
L. Shoshiashvili, A. Razmadze, N. Jejelava, R. Zaridze, L.G. Bit-Babik, A. Faraone
Temperature rise evaluation in human body exposed to RF energy is becoming increasingly important topic related to the future development of the RF exposure safety standards. Therefore the validation of the existing methods like FDTD used in such complex multidisciplinary studies is very important. The accuracy of the FDTD solution of the bio-heat equation which is most often used in this type if studies have been analyzed based on the developed program package. The effect of stair case geometry representation in FDTD grid has been investigated by comparing the test case with analytical solution. In addition comparison was made with the published results. Preliminary data show that in case of constant temperature boundary conditions FDTD results slightly differ from the analytical solution during the transition state of the heat transfer process while there is a much better agreement in steady state regime. In case of convective boundary conditions the steady state temperature distribution at the convective boundary obtained by FDTD method also differ insignificantly from the FEM results reported in literature and temperature values inside the model are almost identical with that from FEM models. The results point to the conclusion that the error in FDTD simulations may be attributed to faster heat exchange which is due to the difference of surface area between the smooth and stair case boundaries of the modeled structures. These results are similar to those reported in T. Samaras et al. (2006). The impact on temperature inside the body far from the boundary is less than 1% while at the boundary is in the range of 4-7% for the models with 0.5 mm grid resolution and tissue like thermal properties
人体暴露于射频能量下的温升评价已成为关系到射频暴露安全标准未来发展的重要课题。因此，在这种复杂的多学科研究中，验证FDTD等现有方法是非常重要的。基于开发的程序包，对这类研究中最常用的生物热方程时域有限差分解的精度进行了分析。通过测试用例与解析解的比较，研究了阶梯几何表示在FDTD网格中的作用。并与已发表的研究结果进行了比较。初步数据表明，在恒温边界条件下，时域有限差分法的结果与解析解在传热过程过渡状态下略有差异，而在稳态状态下则吻合得更好。在对流边界条件下，时域有限差分法得到的对流边界稳态温度分布与文献报道的有限元结果相差不大，模型内的温量值与有限元模型的温量值基本一致。结果表明，时域有限差分模拟的误差可能是由于模拟结构的光滑边界和阶梯边界之间的表面积差异导致的更快的热交换。这些结果与T. Samaras et al.(2006)报道的结果相似。对于网格分辨率为0.5 mm的类组织热性能模型，对远离边界的体内温度的影响小于1%，而在边界处对温度的影响在4-7%之间
{"title":"Validation of Numerical Bioheat FDTD Model","authors":"L. Shoshiashvili, A. Razmadze, N. Jejelava, R. Zaridze, L.G. Bit-Babik, A. Faraone","doi":"10.1109/DIPED.2006.314324","DOIUrl":"https://doi.org/10.1109/DIPED.2006.314324","url":null,"abstract":"Temperature rise evaluation in human body exposed to RF energy is becoming increasingly important topic related to the future development of the RF exposure safety standards. Therefore the validation of the existing methods like FDTD used in such complex multidisciplinary studies is very important. The accuracy of the FDTD solution of the bio-heat equation which is most often used in this type if studies have been analyzed based on the developed program package. The effect of stair case geometry representation in FDTD grid has been investigated by comparing the test case with analytical solution. In addition comparison was made with the published results. Preliminary data show that in case of constant temperature boundary conditions FDTD results slightly differ from the analytical solution during the transition state of the heat transfer process while there is a much better agreement in steady state regime. In case of convective boundary conditions the steady state temperature distribution at the convective boundary obtained by FDTD method also differ insignificantly from the FEM results reported in literature and temperature values inside the model are almost identical with that from FEM models. The results point to the conclusion that the error in FDTD simulations may be attributed to faster heat exchange which is due to the difference of surface area between the smooth and stair case boundaries of the modeled structures. These results are similar to those reported in T. Samaras et al. (2006). The impact on temperature inside the body far from the boundary is less than 1% while at the boundary is in the range of 4-7% for the models with 0.5 mm grid resolution and tissue like thermal properties","PeriodicalId":183082,"journal":{"name":"Proceedings of XIth International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic Acoustic Wave Theory","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132051655","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 : 2006-10-01DOI: 10.1109/DIPED.2006.314308
N. Tsitsas, C. Athanasiadis
A spherical acoustic wave is scattered by a three layered sphere with a soft core. Exact expressions of the fields in every layer and the exterior of the scatterer are established. Low frequency results are then obtained by approximating the exact expression of the scattering cross section. The inverse problem of determining the sphere's center and the layers radii is treated from the knowledge of the scattering cross section's low frequency expansion
{"title":"Direct and Inverse Acoustic Spherical Wave Scattering by a Small Layered Sphere with Soft Core","authors":"N. Tsitsas, C. Athanasiadis","doi":"10.1109/DIPED.2006.314308","DOIUrl":"https://doi.org/10.1109/DIPED.2006.314308","url":null,"abstract":"A spherical acoustic wave is scattered by a three layered sphere with a soft core. Exact expressions of the fields in every layer and the exterior of the scatterer are established. Low frequency results are then obtained by approximating the exact expression of the scattering cross section. The inverse problem of determining the sphere's center and the layers radii is treated from the knowledge of the scattering cross section's low frequency expansion","PeriodicalId":183082,"journal":{"name":"Proceedings of XIth International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic Acoustic Wave Theory","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134561891","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 : 2006-10-01DOI: 10.1109/DIPED.2006.314280
Zhou Yide, Wu Jianbo, Yang Ruiliang, Fan Xiaowei
A new formulation based on a prolate spheroidal coordinate was proposed to describe acoustic pressure in the acoustic field. The radiated acoustic pressures are obtained by means of an expansion of independent functions based on the prolate spheroidal coordinate system. Then the acoustic pressure in the field can be reconstructed by using some measured acoustic pressure signals in the field. The independent function of the traditional HELS is spherical function, which is most suitable for reconstructing pressures radiated a spherical source or sources with a characteristic aspect ratio x:y:z close 1:1:1. While the new method proposed in this paper is suitable for the acoustic sources with a characteristic aspect ratio y:z close 1:1 and x at random, which extends the appropriate application domain of traditional HELS largely. It uses a finite cylinder as an example in this paper, which shows that the new method is feasible and efficiently
{"title":"Reconstructing the Acoustic Pressure Field Using Spheroidal Wave Functions","authors":"Zhou Yide, Wu Jianbo, Yang Ruiliang, Fan Xiaowei","doi":"10.1109/DIPED.2006.314280","DOIUrl":"https://doi.org/10.1109/DIPED.2006.314280","url":null,"abstract":"A new formulation based on a prolate spheroidal coordinate was proposed to describe acoustic pressure in the acoustic field. The radiated acoustic pressures are obtained by means of an expansion of independent functions based on the prolate spheroidal coordinate system. Then the acoustic pressure in the field can be reconstructed by using some measured acoustic pressure signals in the field. The independent function of the traditional HELS is spherical function, which is most suitable for reconstructing pressures radiated a spherical source or sources with a characteristic aspect ratio x:y:z close 1:1:1. While the new method proposed in this paper is suitable for the acoustic sources with a characteristic aspect ratio y:z close 1:1 and x at random, which extends the appropriate application domain of traditional HELS largely. It uses a finite cylinder as an example in this paper, which shows that the new method is feasible and efficiently","PeriodicalId":183082,"journal":{"name":"Proceedings of XIth International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic Acoustic Wave Theory","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122218592","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 : 2006-10-01DOI: 10.1109/DIPED.2006.314300
B. Levin
The flat reflectarray consisting of a feed and an array of secondary microstrip radiators is considered. The method of a turn of a reflective array pattern maximum in the given direction by a change of reflective array elements condensers capacities in response to an electrical signal is offered
{"title":"Reflectarray with any Given Radiation Direction","authors":"B. Levin","doi":"10.1109/DIPED.2006.314300","DOIUrl":"https://doi.org/10.1109/DIPED.2006.314300","url":null,"abstract":"The flat reflectarray consisting of a feed and an array of secondary microstrip radiators is considered. The method of a turn of a reflective array pattern maximum in the given direction by a change of reflective array elements condensers capacities in response to an electrical signal is offered","PeriodicalId":183082,"journal":{"name":"Proceedings of XIth International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic Acoustic Wave Theory","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126038518","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 : 2006-10-01DOI: 10.1109/DIPED.2006.314316
I. V. Tupychak, N. N. Voitovich
A nonlinear integral equation arising in the so-called modified phase problem is considered when the given function is modulus of a vanishing function. The real vanishing solutions to this equation are investigated. Solutions having one and two vanishing points are found numerically and the results are analyzed for two concrete examples
{"title":"Real Vanishing Solutions to Nonlinear Equation Related to Modified Phase Problem","authors":"I. V. Tupychak, N. N. Voitovich","doi":"10.1109/DIPED.2006.314316","DOIUrl":"https://doi.org/10.1109/DIPED.2006.314316","url":null,"abstract":"A nonlinear integral equation arising in the so-called modified phase problem is considered when the given function is modulus of a vanishing function. The real vanishing solutions to this equation are investigated. Solutions having one and two vanishing points are found numerically and the results are analyzed for two concrete examples","PeriodicalId":183082,"journal":{"name":"Proceedings of XIth International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic Acoustic Wave Theory","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125031363","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 : 2006-10-01DOI: 10.1109/DIPED.2006.314288
F. Akleman, A. Yapar
In this study, a longitudinally inhomogeneous dielectric material is loaded in a rectangular cross section waveguide and its permittivity variation is reconstructed using integral equation technique. The analysis of propagation through dielectric loaded waveguide is realized via mode matching technique and the obtained scattering parameters are employed as the measurement data, which is required for the solution of inverse problem by Newton iteration. The validity and reliability of the proposed method has been shown together with numerical applications
{"title":"Reconstruction of Longitudinally Inhomogeneous Dielectric in Waveguides via Integral Equation Technique","authors":"F. Akleman, A. Yapar","doi":"10.1109/DIPED.2006.314288","DOIUrl":"https://doi.org/10.1109/DIPED.2006.314288","url":null,"abstract":"In this study, a longitudinally inhomogeneous dielectric material is loaded in a rectangular cross section waveguide and its permittivity variation is reconstructed using integral equation technique. The analysis of propagation through dielectric loaded waveguide is realized via mode matching technique and the obtained scattering parameters are employed as the measurement data, which is required for the solution of inverse problem by Newton iteration. The validity and reliability of the proposed method has been shown together with numerical applications","PeriodicalId":183082,"journal":{"name":"Proceedings of XIth International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic Acoustic Wave Theory","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126441486","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 : 2006-10-01DOI: 10.1109/DIPED.2006.314278
O. Kusyi, N. N. Voitovich, O. Zamorska
An inverse problem of irregular waveguide shape recognizing with usage of the moving point source inside it, is considered. A combined algorithm is proposed for solving the appropriate direct problem, based on the known cross-section method with applying the opposite directions technique. In combination with the local variations method, this technique most fully uses the information about fixed parts of the recognized waveguide. This approach allows us to minimize the computation costs in each step of the iteration procedure
{"title":"Recognition of Irregular Waveguide Geometry Using Opposite Directions Technique","authors":"O. Kusyi, N. N. Voitovich, O. Zamorska","doi":"10.1109/DIPED.2006.314278","DOIUrl":"https://doi.org/10.1109/DIPED.2006.314278","url":null,"abstract":"An inverse problem of irregular waveguide shape recognizing with usage of the moving point source inside it, is considered. A combined algorithm is proposed for solving the appropriate direct problem, based on the known cross-section method with applying the opposite directions technique. In combination with the local variations method, this technique most fully uses the information about fixed parts of the recognized waveguide. This approach allows us to minimize the computation costs in each step of the iteration procedure","PeriodicalId":183082,"journal":{"name":"Proceedings of XIth International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic Acoustic Wave Theory","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115843691","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 : 2006-10-01DOI: 10.1109/DIPED.2006.314282
B. Katsenelenbaum
A plane wave falls onto the body with an impedance boundary. Magnitude of the back-scattered spherical wave is compared with that of the wave scattered from the body of the same shape, having zero impedance. The impedance (in general, variable over the boundary) can be created such that the back scattering will be noticeably smaller than that from the smooth metallic body. This can be made, e. g., by cutting a set of channels on the boundary, i.e., by crimping. Such a way of the radar protection can be applied also near the edges and vertices where usage of the absorbing coating is not effective enough
{"title":"Inverse Scattering from Bodies with Impedance Boundary","authors":"B. Katsenelenbaum","doi":"10.1109/DIPED.2006.314282","DOIUrl":"https://doi.org/10.1109/DIPED.2006.314282","url":null,"abstract":"A plane wave falls onto the body with an impedance boundary. Magnitude of the back-scattered spherical wave is compared with that of the wave scattered from the body of the same shape, having zero impedance. The impedance (in general, variable over the boundary) can be created such that the back scattering will be noticeably smaller than that from the smooth metallic body. This can be made, e. g., by cutting a set of channels on the boundary, i.e., by crimping. Such a way of the radar protection can be applied also near the edges and vertices where usage of the absorbing coating is not effective enough","PeriodicalId":183082,"journal":{"name":"Proceedings of XIth International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic Acoustic Wave Theory","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115734184","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 : 2006-10-01DOI: 10.1109/DIPED.2006.314302
M. Protsenko, S. Nesteruk
An implementation of combined helical antenna with controlled radiation polarization on the basis of two windings coming from the opposite direction for a frequency range is proposed. The possibility of linear polarization and the plane of polarization control are achieved by usage of reactance. The calculation and analysis of directional pattern and polarization pattern were carried out. The model of antenna was experimentally tested as well
{"title":"Research of Antenna with Controlled Radiation Polarization","authors":"M. Protsenko, S. Nesteruk","doi":"10.1109/DIPED.2006.314302","DOIUrl":"https://doi.org/10.1109/DIPED.2006.314302","url":null,"abstract":"An implementation of combined helical antenna with controlled radiation polarization on the basis of two windings coming from the opposite direction for a frequency range is proposed. The possibility of linear polarization and the plane of polarization control are achieved by usage of reactance. The calculation and analysis of directional pattern and polarization pattern were carried out. The model of antenna was experimentally tested as well","PeriodicalId":183082,"journal":{"name":"Proceedings of XIth International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic Acoustic Wave Theory","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128855121","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 : 2006-10-01DOI: 10.1109/DIPED.2006.314298
M. Andreev, S. G. Aleksin, O. Drobakhin, V. G. Korotkaya
The some results of numerical simulation for the Gel'fand-Levitan method of reconstruction of discrete profile of permittivity are presented. Some examples of noise influence and threshold application are considered. The method is based on spectral analysis of frequency data with generalized pencil-of-function method
{"title":"1-D Inverse Problem Solution for Dielectric Structure with Discrete Profile of Permittivity: Gel'fand-Levitan Method","authors":"M. Andreev, S. G. Aleksin, O. Drobakhin, V. G. Korotkaya","doi":"10.1109/DIPED.2006.314298","DOIUrl":"https://doi.org/10.1109/DIPED.2006.314298","url":null,"abstract":"The some results of numerical simulation for the Gel'fand-Levitan method of reconstruction of discrete profile of permittivity are presented. Some examples of noise influence and threshold application are considered. The method is based on spectral analysis of frequency data with generalized pencil-of-function method","PeriodicalId":183082,"journal":{"name":"Proceedings of XIth International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic Acoustic Wave Theory","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129198373","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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