Pub Date : 2011-10-17DOI: 10.1109/CEM.2011.6047333
H. Wallén, J. Kataja
Ideally sharp edges can be computationally somewhat difficult, but the model is theoretically reasonable except for certain ranges of negative material parameters. In the quasistatic limit, negative permittivity wedges appear to support unphysical edge modes with infinite energy, and this theoretical anomaly show up as nonsensical numerical results in both static and dynamic simulations.
{"title":"Some computational aspects of too sharp edges","authors":"H. Wallén, J. Kataja","doi":"10.1109/CEM.2011.6047333","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047333","url":null,"abstract":"Ideally sharp edges can be computationally somewhat difficult, but the model is theoretically reasonable except for certain ranges of negative material parameters. In the quasistatic limit, negative permittivity wedges appear to support unphysical edge modes with infinite energy, and this theoretical anomaly show up as nonsensical numerical results in both static and dynamic simulations.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130426987","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 : 2011-10-17DOI: 10.1109/CEM.2011.6047320
A. Polimeridis, J. Mosig
Surface integral equation (SIE) formulations have reached a workhorse status in computational electromagnetics over the last decades. The numerical solution of Fredholm first and second kind SIEs is typically carried out by means of Galerkin (or Petrov-Galerkin) method of moments discretization schemes. The accuracy and stability of those schemes are strongly dependent on the accurate and efficient computation of the associated impedance matrix elements. In the case of disjoint supports of basis and testing functions, the arising multidimensional integrals are regular, allowing a straightforward numerical integration. Hence, special emphasis is naturally laid upon the most challenging cases that appear when those supports are overlapping or share some common points, thus, giving rise to singular integrals. More specifically, the singular integrals that stem from MoM SIE formulations can be categorized into weakly singular (improper Riemann integrable or 1/R) and strongly singular (Cauchy or 1/R2), provided certain restrictions to both basis and testing functions. We will present our latest advances on the fast and accurate integration of the above mentioned 4-D singular integrals for both div-conforming and curl-conforming testing functions over triangular tessellations. The numerical experiments have been undertaken on Matlab and C++ platforms with double precision arithmetic, while the reference values obtained with high precision arithmetic exhibit smooth convergence beyond 16 significant digits. As it will be clearly demonstrated by the results, the proposed method leads to exponential convergence both for 1/R and 1/R2 singularities with the accuracy being limited only by the incidental presence of error propagation effects in the numerical integration of sufficiently smooth functions. In any case, the results converge to a minimum of 13 significant digits (for most of the cases close to machine precision) with unmatched efficiency, thus allowing a safe shift of future research studies on other aspects of surface integral equation formulations.
{"title":"On the numerically exact integration of singular Galerkin impedance matrix elements in computational electromagnetics","authors":"A. Polimeridis, J. Mosig","doi":"10.1109/CEM.2011.6047320","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047320","url":null,"abstract":"Surface integral equation (SIE) formulations have reached a workhorse status in computational electromagnetics over the last decades. The numerical solution of Fredholm first and second kind SIEs is typically carried out by means of Galerkin (or Petrov-Galerkin) method of moments discretization schemes. The accuracy and stability of those schemes are strongly dependent on the accurate and efficient computation of the associated impedance matrix elements. In the case of disjoint supports of basis and testing functions, the arising multidimensional integrals are regular, allowing a straightforward numerical integration. Hence, special emphasis is naturally laid upon the most challenging cases that appear when those supports are overlapping or share some common points, thus, giving rise to singular integrals. More specifically, the singular integrals that stem from MoM SIE formulations can be categorized into weakly singular (improper Riemann integrable or 1/R) and strongly singular (Cauchy or 1/R2), provided certain restrictions to both basis and testing functions. We will present our latest advances on the fast and accurate integration of the above mentioned 4-D singular integrals for both div-conforming and curl-conforming testing functions over triangular tessellations. The numerical experiments have been undertaken on Matlab and C++ platforms with double precision arithmetic, while the reference values obtained with high precision arithmetic exhibit smooth convergence beyond 16 significant digits. As it will be clearly demonstrated by the results, the proposed method leads to exponential convergence both for 1/R and 1/R2 singularities with the accuracy being limited only by the incidental presence of error propagation effects in the numerical integration of sufficiently smooth functions. In any case, the results converge to a minimum of 13 significant digits (for most of the cases close to machine precision) with unmatched efficiency, thus allowing a safe shift of future research studies on other aspects of surface integral equation formulations.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129900854","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 : 2011-10-17DOI: 10.1109/CEM.2011.6047334
N. Tsitsas, D. Frantzeskakis
Wave propagation in nonlinear negative index metamaterials is investigated by directly implementing the reductive perturbation method to Faraday's and Ampére's laws. In this way, we derive a second-order and a third-order nonlinear Schrödinger equation, describing solitons of moderate and ultra-short pulse widths, respectively. We find necessary conditions and derive exact bright and dark soliton solutions of these equations for the electric and magnetic field envelopes. Directions of future work towards the modelling of wave propagation in more complicated types of nonlinear negative index metamaterials (e.g., chiral metamaterials) are pointed out.
{"title":"Nonlinear wave propagation in negative index metamaterials","authors":"N. Tsitsas, D. Frantzeskakis","doi":"10.1109/CEM.2011.6047334","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047334","url":null,"abstract":"Wave propagation in nonlinear negative index metamaterials is investigated by directly implementing the reductive perturbation method to Faraday's and Ampére's laws. In this way, we derive a second-order and a third-order nonlinear Schrödinger equation, describing solitons of moderate and ultra-short pulse widths, respectively. We find necessary conditions and derive exact bright and dark soliton solutions of these equations for the electric and magnetic field envelopes. Directions of future work towards the modelling of wave propagation in more complicated types of nonlinear negative index metamaterials (e.g., chiral metamaterials) are pointed out.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123318343","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 : 2011-10-17DOI: 10.1109/CEM.2011.6047326
S. Hegler, R. Hahnel, D. Plettemeier
A radar backscattering simulator based on the method of physical optics is presented in this paper. In contrast to other tools, the creation of the simulation geometry is closely intertwined with the simulator core. Algorithms as well as the parallelization scheme will be explained. Performance will be compared, both with regard to accuracy of the results and computation time.
{"title":"A high performance physical-optics clutter simulator with on-the-fly mesh generation","authors":"S. Hegler, R. Hahnel, D. Plettemeier","doi":"10.1109/CEM.2011.6047326","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047326","url":null,"abstract":"A radar backscattering simulator based on the method of physical optics is presented in this paper. In contrast to other tools, the creation of the simulation geometry is closely intertwined with the simulator core. Algorithms as well as the parallelization scheme will be explained. Performance will be compared, both with regard to accuracy of the results and computation time.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131082604","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 : 2011-10-17DOI: 10.1109/CEM.2011.6047339
O. Kilic, E. El-Araby, V. Dang
The current antenna technology is driven by both military and commercial applications to achieve multi-functionality with persistent connectivity in an integrated platform. The packaging and performance of the antenna in this integrated platform are thus critical factors to consider as an antenna designer. The need for reliable and efficient numerical techniques has been growing as the designs get more complex and a good prediction of system performance becomes essential for cost reduction. There are numerous ways of addressing this issue, such as developing hybrid methods that can avoid the numerical inefficiency of full wave methods while comparable accuracy can be achieved as effectively by asymptotic techniques. Another approach is to implement fast computational methods that utilize parallel computing platforms. It is the latter that is the focus of this paper with a particular focus on the use of general purpose graphics processing units (GPGPU) and field programmable gate arrays (FPGA). This paper will investigate both of these platforms in their applications to numerically intensive electromagnetic simulations. Weaknesses and strengths of both platforms will be investigated in the context of ease of use, efficiency, and potential for accelerated computations.
{"title":"Hardware accelerated computing for electromagnetics applications","authors":"O. Kilic, E. El-Araby, V. Dang","doi":"10.1109/CEM.2011.6047339","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047339","url":null,"abstract":"The current antenna technology is driven by both military and commercial applications to achieve multi-functionality with persistent connectivity in an integrated platform. The packaging and performance of the antenna in this integrated platform are thus critical factors to consider as an antenna designer. The need for reliable and efficient numerical techniques has been growing as the designs get more complex and a good prediction of system performance becomes essential for cost reduction. There are numerous ways of addressing this issue, such as developing hybrid methods that can avoid the numerical inefficiency of full wave methods while comparable accuracy can be achieved as effectively by asymptotic techniques. Another approach is to implement fast computational methods that utilize parallel computing platforms. It is the latter that is the focus of this paper with a particular focus on the use of general purpose graphics processing units (GPGPU) and field programmable gate arrays (FPGA). This paper will investigate both of these platforms in their applications to numerically intensive electromagnetic simulations. Weaknesses and strengths of both platforms will be investigated in the context of ease of use, efficiency, and potential for accelerated computations.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"4 1-2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114097426","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 : 2011-10-17DOI: 10.1109/CEM.2011.6047336
B. Carpentieri, Y. Jing, Tingzhu Huang, W. Pi, X. Sheng
Boundary element discretizations of surface and hybrid surface/volume formulations of electromagnetic scattering problems generate large and dense systems of linear equations that are tough to solve by iterative techniques. The restarted generalized minimal residual (GMRES) method is virtually always used when the systems are non-Hermitian and indefinite. However, it may be prohibitively expensive especially for large scale out-of-core integral codes. We present experiments with a novel class of iterative methods that have constant, low memory and algorithmic cost per iteration. The results on some selected matrix problems arising from realistic radar-cross-section calculation indicate that the new family of algorithms is amazingly competitive with the most popular iterative techniques in use today for solving linear systems.
{"title":"A novel family of iterative solvers for method of moments discretizations of maxwell's equations","authors":"B. Carpentieri, Y. Jing, Tingzhu Huang, W. Pi, X. Sheng","doi":"10.1109/CEM.2011.6047336","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047336","url":null,"abstract":"Boundary element discretizations of surface and hybrid surface/volume formulations of electromagnetic scattering problems generate large and dense systems of linear equations that are tough to solve by iterative techniques. The restarted generalized minimal residual (GMRES) method is virtually always used when the systems are non-Hermitian and indefinite. However, it may be prohibitively expensive especially for large scale out-of-core integral codes. We present experiments with a novel class of iterative methods that have constant, low memory and algorithmic cost per iteration. The results on some selected matrix problems arising from realistic radar-cross-section calculation indicate that the new family of algorithms is amazingly competitive with the most popular iterative techniques in use today for solving linear systems.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122444873","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 : 2011-10-17DOI: 10.1109/CEM.2011.6047319
M. Taskinen
Singular double integrals of the Green's function and its gradients are calculated fully analytically without numerical integrations from the series expansion of the Green's function. The expansion term integrals are calculated for general 3-D simplexes recursively by lowering the order of the expansion term or the dimension of the integration. The accuracy is verified with some numerical experiments of electromagnetic surface integral equation.
{"title":"On the fully analytical integration of singular double integrals arising from the integral equation methods","authors":"M. Taskinen","doi":"10.1109/CEM.2011.6047319","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047319","url":null,"abstract":"Singular double integrals of the Green's function and its gradients are calculated fully analytically without numerical integrations from the series expansion of the Green's function. The expansion term integrals are calculated for general 3-D simplexes recursively by lowering the order of the expansion term or the dimension of the integration. The accuracy is verified with some numerical experiments of electromagnetic surface integral equation.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129870092","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 : 2011-10-17DOI: 10.1109/CEM.2011.6047323
G. Verissimo, J. Dubard, M. Ney, C. Pichot
A new 3-D transmission line matrix-twin wire (TLM-TW) numerical scheme is proposed for modeling thin wires buried in a general inhomogeneous, dispersive, conductive medium. To solve the time convolution product introduced by the dispersive medium, a recursive algorithm obtained by bilinear Z-transform approach is used. This technique is developed for electrically dispersive media (i.e., magnetically non-dispersive) and its generality allows the use of any kind of Debye and Lorentz models or media represented by a ratio of polynomials with full power of (j ω). The TLM-TW numerical scheme is first validated through the simulation of a canonical thin lead cable surrounded by a homogeneous Lorentz dispersive medium. Then, the numerical study of an umbrella antenna, radiating structure typically used in VLF transmissions, is investigated.
{"title":"TLM modeling of thin wires in dispersive media","authors":"G. Verissimo, J. Dubard, M. Ney, C. Pichot","doi":"10.1109/CEM.2011.6047323","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047323","url":null,"abstract":"A new 3-D transmission line matrix-twin wire (TLM-TW) numerical scheme is proposed for modeling thin wires buried in a general inhomogeneous, dispersive, conductive medium. To solve the time convolution product introduced by the dispersive medium, a recursive algorithm obtained by bilinear Z-transform approach is used. This technique is developed for electrically dispersive media (i.e., magnetically non-dispersive) and its generality allows the use of any kind of Debye and Lorentz models or media represented by a ratio of polynomials with full power of (j ω). The TLM-TW numerical scheme is first validated through the simulation of a canonical thin lead cable surrounded by a homogeneous Lorentz dispersive medium. Then, the numerical study of an umbrella antenna, radiating structure typically used in VLF transmissions, is investigated.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126751722","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 : 2011-10-17DOI: 10.1109/CEM.2011.6047340
A. Barka, F. Roux
This paper presents the implementation of finite element tearing and interconnecting (FETI) methods on parallel MPI machines for solving electromagnetic frequency domain problems encountered in the design of electromagnetic band gap (EBG) materials and antenna arrays.
{"title":"High performance finite elements for the electromagnetic characterization of metamaterials and antenna arrays","authors":"A. Barka, F. Roux","doi":"10.1109/CEM.2011.6047340","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047340","url":null,"abstract":"This paper presents the implementation of finite element tearing and interconnecting (FETI) methods on parallel MPI machines for solving electromagnetic frequency domain problems encountered in the design of electromagnetic band gap (EBG) materials and antenna arrays.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129541868","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 : 2011-10-17DOI: 10.1109/CEM.2011.6047342
N. Ozdemir, C. Simovski, D. Morits, C. Craeye
Multiple-scattering-based macro basis function approach complemented with the incomplete QR algorithm provides an efficient method of moments solution for the analysis of infinite and finite arrays of magnetic and magneto-electric nanoclusters. The efficiency and the accuracy of the combined approach have been validated with respect to the brute-force implementation of the method of moments and the finite element method-based commercial simulator Ansoft HFSS, respectively, for an infinite doubly periodic array of magnetic nanaoclusters in the optical frequency range.
{"title":"Efficient method of moments analysis of infinite and finite arrays of magnetic nanoclusters in the optical frequency range","authors":"N. Ozdemir, C. Simovski, D. Morits, C. Craeye","doi":"10.1109/CEM.2011.6047342","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047342","url":null,"abstract":"Multiple-scattering-based macro basis function approach complemented with the incomplete QR algorithm provides an efficient method of moments solution for the analysis of infinite and finite arrays of magnetic and magneto-electric nanoclusters. The efficiency and the accuracy of the combined approach have been validated with respect to the brute-force implementation of the method of moments and the finite element method-based commercial simulator Ansoft HFSS, respectively, for an infinite doubly periodic array of magnetic nanaoclusters in the optical frequency range.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125858679","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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