{"title":"Electromagnetic surface wave diffraction by the joint of perfectly conducting and dielectric slabs","authors":"E. Vasil'ev, V. Okhmatovsky","doi":"10.1109/AEM.1996.873041","DOIUrl":"https://doi.org/10.1109/AEM.1996.873041","url":null,"abstract":"","PeriodicalId":445510,"journal":{"name":"Trans Black Sea Region Symposium on Applied Electromagnetism","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121330560","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}
In this paper, the lossy transmission line is represented as a two port network which consists of characteristic impedances or admittances and waveform generators. Equivalent circuits are synthesized for characteristic impedances and the exponential propagation function by making use of the Pade approximations; on using a network of lumped elements and ideal transmission line to approximate the time response of each lossy transmission line, or each lossy multiconductor lines. The approximated circuit models are suitable for existing general purpose circuit simulators as SPICE or PSPICE.
{"title":"Electromagnetic transient analysis of uniform lossy transmission lines based on the pade approximations of line's characteristics","authors":"P. Cipo, V. Zenjo","doi":"10.1109/AEM.1996.873079","DOIUrl":"https://doi.org/10.1109/AEM.1996.873079","url":null,"abstract":"In this paper, the lossy transmission line is represented as a two port network which consists of characteristic impedances or admittances and waveform generators. Equivalent circuits are synthesized for characteristic impedances and the exponential propagation function by making use of the Pade approximations; on using a network of lumped elements and ideal transmission line to approximate the time response of each lossy transmission line, or each lossy multiconductor lines. The approximated circuit models are suitable for existing general purpose circuit simulators as SPICE or PSPICE.","PeriodicalId":445510,"journal":{"name":"Trans Black Sea Region Symposium on Applied Electromagnetism","volume":"13 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114129270","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}
Consideration of the effect of active medium properties on natural oscillations, specifically on mode and spatial structures of laser radiation, is a crucial problem of the laser theory. In the case of steady state generation, the problem reduces to solving the steady state wave equation for the field inducing polarization of the medium and satisfying some boundary condition at optical companents of the laser resonator. The macroscopic polarization of the Doppler ensemble is related to the exciting field by a spatially nonlocal dependences. A third order perturbation calculation of polarization bazed on the solving density-matrix equations for the two-level system is presented. The novel feature of this theory is the consideration of the Gaussian spatial structure of the laser beam. I
{"title":"Calculation of natural oscillations of a resonator with a nonlinear active medium","authors":"T.V. Radina","doi":"10.1109/AEM.1996.873149","DOIUrl":"https://doi.org/10.1109/AEM.1996.873149","url":null,"abstract":"Consideration of the effect of active medium properties on natural oscillations, specifically on mode and spatial structures of laser radiation, is a crucial problem of the laser theory. In the case of steady state generation, the problem reduces to solving the steady state wave equation for the field inducing polarization of the medium and satisfying some boundary condition at optical companents of the laser resonator. The macroscopic polarization of the Doppler ensemble is related to the exciting field by a spatially nonlocal dependences. A third order perturbation calculation of polarization bazed on the solving density-matrix equations for the two-level system is presented. The novel feature of this theory is the consideration of the Gaussian spatial structure of the laser beam. I","PeriodicalId":445510,"journal":{"name":"Trans Black Sea Region Symposium on Applied Electromagnetism","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115809257","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}
Since the exact evaluation of the scattered by a random rough d a c e electromagnetic field is impossible, one has to fall back on some approximate methods. The recently suggested such approximations are result of the efforts to deal with the scattering process from natural (earth or sea) or man-made surfaces whose characteristic roughness dimension is of order of the wavelength of the sounding field. Such a necessity comes fiom the limited range of validity of the classical approximate methods the Kirchhoff approximation (KA) and the perturbation theory (PT) which are accurate in two limiting cases only: when the incident field wavelength X is much smaller than the lateral correlation length or much greater than the nns surface height, respectively. Often, however, the roughness spectrum of the aurfaces of interest i s very wide in which case neither KA nor PT done applies. In this report we review four of the mod promising approaches to the problem of interest, namely, the phase perturbation theory (PPT) [1,2] the Lynch variational method (LVM) 131, the local parabolic approximation (LPA) [4], and the small slope approximation ( S A ) 151 and compare their respective ranges of validity. The approximations are examined in the case of one-dimensional normally distributed random rough surfaces on which either Mchle t (PPT and LVM) or Neumann (SSA) or both Dirichlet and Neumaan (LPA) boundary conditions hold. Some of the most important findings and results (based on our own studies) whicb will be discussed, include: 1) The PPT is not limited to cmes of either mall roughness or gentle undulations and smoothly interpolates between the two classical approximations 16-81. 2) The asymptotic expansions of the phase perturbation scattering CTOSS section using the ratio of the rms height and slope as large parameter facilitate the practical application of the method
由于对随机粗糙电磁场散射的精确估计是不可能的，人们不得不求助于一些近似的方法。最近提出的这种近似是努力处理来自自然(陆地或海洋)或人造表面的散射过程的结果，这些表面的特征粗糙度尺寸是探测场波长的数量级。这种必要性来自经典近似方法Kirchhoff近似(KA)和微扰理论(PT)的有效性范围有限，它们仅在两种极限情况下是准确的:入射场波长X分别远小于横向相关长度或远大于nns表面高度。然而，通常，感兴趣的表面的粗糙度谱非常宽，在这种情况下，KA和PT都不适用。在本报告中，我们回顾了四种最有前途的方法，即相摄动理论(PPT)[1,2]、Lynch变分方法(LVM) 131、局部抛物近似(LPA)[4]和小斜率近似(sa) 151，并比较了它们各自的有效性范围。在一维正态分布随机粗糙表面的近似情况下进行了检验，其中mcchle t (PPT和LVM)或Neumann (SSA)或Dirichlet和neuaan (LPA)边界条件都成立。将讨论的一些最重要的发现和结果(基于我们自己的研究)包括:1)PPT不限于小粗糙度或温和波动的到来，并且在两个经典近似之间平滑地插入16-81。2)以均方根高度与斜率之比为大参数的相摄动散射ctos截面渐近展开便于该方法的实际应用
{"title":"New approximations in the theory of rough surface scattering","authors":"K. Ivanova, O. Yordanov, M. A. Michalev","doi":"10.1109/AEM.1996.873040","DOIUrl":"https://doi.org/10.1109/AEM.1996.873040","url":null,"abstract":"Since the exact evaluation of the scattered by a random rough d a c e electromagnetic field is impossible, one has to fall back on some approximate methods. The recently suggested such approximations are result of the efforts to deal with the scattering process from natural (earth or sea) or man-made surfaces whose characteristic roughness dimension is of order of the wavelength of the sounding field. Such a necessity comes fiom the limited range of validity of the classical approximate methods the Kirchhoff approximation (KA) and the perturbation theory (PT) which are accurate in two limiting cases only: when the incident field wavelength X is much smaller than the lateral correlation length or much greater than the nns surface height, respectively. Often, however, the roughness spectrum of the aurfaces of interest i s very wide in which case neither KA nor PT done applies. In this report we review four of the mod promising approaches to the problem of interest, namely, the phase perturbation theory (PPT) [1,2] the Lynch variational method (LVM) 131, the local parabolic approximation (LPA) [4], and the small slope approximation ( S A ) 151 and compare their respective ranges of validity. The approximations are examined in the case of one-dimensional normally distributed random rough surfaces on which either Mchle t (PPT and LVM) or Neumann (SSA) or both Dirichlet and Neumaan (LPA) boundary conditions hold. Some of the most important findings and results (based on our own studies) whicb will be discussed, include: 1) The PPT is not limited to cmes of either mall roughness or gentle undulations and smoothly interpolates between the two classical approximations 16-81. 2) The asymptotic expansions of the phase perturbation scattering CTOSS section using the ratio of the rms height and slope as large parameter facilitate the practical application of the method","PeriodicalId":445510,"journal":{"name":"Trans Black Sea Region Symposium on Applied Electromagnetism","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121695859","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}
It is well known, that absorption does not only attenuate EM waves in random media, but changes their statistical characteristics essentially [1,2]. Especially grate effects can be observed in the case of anisotropic absorption of scattered waves.
{"title":"Some effects caused by anisotropic absorption of EM waves in random media","authors":"A. Aistov, V. Gavrilenko","doi":"10.1109/AEM.1996.872839","DOIUrl":"https://doi.org/10.1109/AEM.1996.872839","url":null,"abstract":"It is well known, that absorption does not only attenuate EM waves in random media, but changes their statistical characteristics essentially [1,2]. Especially grate effects can be observed in the case of anisotropic absorption of scattered waves.","PeriodicalId":445510,"journal":{"name":"Trans Black Sea Region Symposium on Applied Electromagnetism","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123742146","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}
The reconstruction of the refractive index of a dielectric body from scattered field data is known as the inverse scattering problem. In the present work this problem is addressed within the Heitler equation method. This equation was originally used by Heitler in his treatment of radiation damping and relates the on shell components of the T matrix directly to the scattering potential. The motivation for using, this equation to inverse scattering problems stems from the1act that the data collected in a scattering experiment contain only the components that lie on the energy shell. We shall limit our attention only to the cases where the wave propagation is governed by the scalar Helmholtz equation. The theoretical formulation developed applies to the general two dimensional problem. Furthermore, an iterative reconstruction algorithm that recovers the unknown index of refraction is introduced. The proposed method is tested with simulated scattered field data. The scattering objects used are, assumed to be two dimensional and purely dielectric. In addition, for simplification purposes, they possess cylindrical symmetry. The results indicate that this method can improve Upon the Born approximation. Specifically it is shown that the method converges to a solution after a few a iterations with a great improvement on a Mean Square Error criterion compared to the Born method. The method works equally well for lossy and non-lossy objects and the greatest improvement is observed. for the imaginary part of the- refractive index.
{"title":"Inverse scattering using the heiyler equation","authors":"K. T. Ladas, T. A. Maniatis, N. Uzunoglu","doi":"10.1109/AEM.1996.873048","DOIUrl":"https://doi.org/10.1109/AEM.1996.873048","url":null,"abstract":"The reconstruction of the refractive index of a dielectric body from scattered field data is known as the inverse scattering problem. In the present work this problem is addressed within the Heitler equation method. This equation was originally used by Heitler in his treatment of radiation damping and relates the on shell components of the T matrix directly to the scattering potential. The motivation for using, this equation to inverse scattering problems stems from the1act that the data collected in a scattering experiment contain only the components that lie on the energy shell. We shall limit our attention only to the cases where the wave propagation is governed by the scalar Helmholtz equation. The theoretical formulation developed applies to the general two dimensional problem. Furthermore, an iterative reconstruction algorithm that recovers the unknown index of refraction is introduced. The proposed method is tested with simulated scattered field data. The scattering objects used are, assumed to be two dimensional and purely dielectric. In addition, for simplification purposes, they possess cylindrical symmetry. The results indicate that this method can improve Upon the Born approximation. Specifically it is shown that the method converges to a solution after a few a iterations with a great improvement on a Mean Square Error criterion compared to the Born method. The method works equally well for lossy and non-lossy objects and the greatest improvement is observed. for the imaginary part of the- refractive index.","PeriodicalId":445510,"journal":{"name":"Trans Black Sea Region Symposium on Applied Electromagnetism","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131454614","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}
This work presents a consistent, full-dynamic, non-linear mathematical approach to the formulation of deformable dielectrics subjected to electromagnetic interactions. The theory includes effects as electric quadrupole moments and polarisation inertia which are useful for the mathematical description of acoustical and optical activity. The model, from which the description is obtained, consists of an electronic charge continuum coupled to a lattice continuum (Tiersten's model). The notion of the internal coordinates i s inserted in order to the effects of electric and magnetic moments be described. The thermomechanical balance laws of continuum mechanics (conservation of Mass, balance of Momentum, balance of Moment of Momentum, conservation of Energy and Entropy Inequality) and the balance laws of non-relativistic Electrodynamics of moving media (Faraday's, Ambere's and Gauss' laws) are postulated in integral form, from which the field equations, the "intramolecular force balance law" and constitutive relations are obtained systematically.
{"title":"A dynamic theory of elastic dielectrics with electric quadrupole polarisation and polarisation inertia","authors":"E. Hadjigeorgiou, V. K. Kalpakidis, V.C. Massalas","doi":"10.1109/AEM.1996.873104","DOIUrl":"https://doi.org/10.1109/AEM.1996.873104","url":null,"abstract":"This work presents a consistent, full-dynamic, non-linear mathematical approach to the formulation of deformable dielectrics subjected to electromagnetic interactions. The theory includes effects as electric quadrupole moments and polarisation inertia which are useful for the mathematical description of acoustical and optical activity. The model, from which the description is obtained, consists of an electronic charge continuum coupled to a lattice continuum (Tiersten's model). The notion of the internal coordinates i s inserted in order to the effects of electric and magnetic moments be described. The thermomechanical balance laws of continuum mechanics (conservation of Mass, balance of Momentum, balance of Moment of Momentum, conservation of Energy and Entropy Inequality) and the balance laws of non-relativistic Electrodynamics of moving media (Faraday's, Ambere's and Gauss' laws) are postulated in integral form, from which the field equations, the \"intramolecular force balance law\" and constitutive relations are obtained systematically.","PeriodicalId":445510,"journal":{"name":"Trans Black Sea Region Symposium on Applied Electromagnetism","volume":"295 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115133650","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}
{"title":"New method for obtaining ultrashort electromagnetic pulses","authors":"A. Melikian, S. Sahakian","doi":"10.1109/AEM.1996.873158","DOIUrl":"https://doi.org/10.1109/AEM.1996.873158","url":null,"abstract":"","PeriodicalId":445510,"journal":{"name":"Trans Black Sea Region Symposium on Applied Electromagnetism","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121240725","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}
In order to solve the so called inverse problem in electrocardiography (IECG) in this study we try to analyse, like a first step, the variation of the bean potential (charges) with conductivity in each of the considering model tissues. In other words, we want to determine the cardiac potential distribution in 39 sagital sections of the human body. In this way knowing the conductivities of each human tissue: bone, muscle, heart muscle, lung, fat, blood, and also the cardiac charge distribution (like current density) for each sagital section. The unique source of current in the considered human body zone is the heart.
{"title":"A quantitative 2-D analysis of the heart electrical activity dependence with tissue conductivity using the MagNet software program","authors":"C. Michael, N. Uzunoglu","doi":"10.1109/AEM.1996.872889","DOIUrl":"https://doi.org/10.1109/AEM.1996.872889","url":null,"abstract":"In order to solve the so called inverse problem in electrocardiography (IECG) in this study we try to analyse, like a first step, the variation of the bean potential (charges) with conductivity in each of the considering model tissues. In other words, we want to determine the cardiac potential distribution in 39 sagital sections of the human body. In this way knowing the conductivities of each human tissue: bone, muscle, heart muscle, lung, fat, blood, and also the cardiac charge distribution (like current density) for each sagital section. The unique source of current in the considered human body zone is the heart.","PeriodicalId":445510,"journal":{"name":"Trans Black Sea Region Symposium on Applied Electromagnetism","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132533036","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}
G. Kyriacou, C. Koukourlis, P. Bonovas, J. Sahalos
{"title":"A reconstruction algorithm for three dimensional electrical impedance tomography","authors":"G. Kyriacou, C. Koukourlis, P. Bonovas, J. Sahalos","doi":"10.1109/AEM.1996.872887","DOIUrl":"https://doi.org/10.1109/AEM.1996.872887","url":null,"abstract":"","PeriodicalId":445510,"journal":{"name":"Trans Black Sea Region Symposium on Applied Electromagnetism","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132904621","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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