Pub Date : 2011-10-17DOI: 10.1109/CEM.2011.6047348
M. Moghaddam, X. Duan, Y. Goykhman, Alireza Tabatabaeenejad
Several layered rough surface and random media scattering models recently developed are discussed, including analytical methods based on small perturbation method and the stabilized extended boundary condition method. It is also shown how some of these models are being used to retrieve subsurface properties from synthetic and experimental data. This is an overview paper on the above topics, with many of them described in more detail in other papers whose citations are provided here.
{"title":"Electromagnetic scattering models of layered random rough surfaces and their role in addressing some of the grand challenges of climate research","authors":"M. Moghaddam, X. Duan, Y. Goykhman, Alireza Tabatabaeenejad","doi":"10.1109/CEM.2011.6047348","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047348","url":null,"abstract":"Several layered rough surface and random media scattering models recently developed are discussed, including analytical methods based on small perturbation method and the stabilized extended boundary condition method. It is also shown how some of these models are being used to retrieve subsurface properties from synthetic and experimental data. This is an overview paper on the above topics, with many of them described in more detail in other papers whose citations are provided here.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"39 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":"121811259","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.2011.6047355
R. Graglia
New families of hierarchical curl and divergence-conforming vector bases for the most commonly used two — and three-dimensional cells are directly constructed from orthogonal scalar polynomials to enhance their linear independence, which is a simpler process than an orthogonalization applied to the final vector functions. These functions span the mixed-order (or reduced) spaces of Nédélec and can be used to deal with structures meshed by a mixture of cells of different geometry.
{"title":"High-order vector bases for computational electromagnetics","authors":"R. Graglia","doi":"10.1109/CEM.2011.6047355","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047355","url":null,"abstract":"New families of hierarchical curl and divergence-conforming vector bases for the most commonly used two — and three-dimensional cells are directly constructed from orthogonal scalar polynomials to enhance their linear independence, which is a simpler process than an orthogonalization applied to the final vector functions. These functions span the mixed-order (or reduced) spaces of Nédélec and can be used to deal with structures meshed by a mixture of cells of different geometry.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"212 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":"116429200","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.2011.6047344
B. Kolundžija, M. Tasic, D. Olćan, D. Zoric, S. Stevanetic
Method of moments applied to surface integral equations combined with higher-order basis functions enables full-wave analysis in frequency domain of complex and relatively large structures. The electrical size of solvable problems can be further extended using different techniques: symmetry of the problem, "smart reduction" of expansion orders, physical optics driven method of moments, iterative methods, multilevel fast multipole algorithm, out-of-core solver, and parallelization at CPU/GPU. Results are presented for: (1) monostatic RCS of cube of side 50λ (100λ), (2) beam steering of array of 40 by 40 microstrip patch antennas at 9.2 GHz, and (3) beam steering of 4 by 4 patch antennas at 2 GHz (5 GHz), placed on a 19-m long helicopter.
{"title":"Full-wave analysis of electrically large structures on desktop PCs","authors":"B. Kolundžija, M. Tasic, D. Olćan, D. Zoric, S. Stevanetic","doi":"10.1109/CEM.2011.6047344","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047344","url":null,"abstract":"Method of moments applied to surface integral equations combined with higher-order basis functions enables full-wave analysis in frequency domain of complex and relatively large structures. The electrical size of solvable problems can be further extended using different techniques: symmetry of the problem, \"smart reduction\" of expansion orders, physical optics driven method of moments, iterative methods, multilevel fast multipole algorithm, out-of-core solver, and parallelization at CPU/GPU. Results are presented for: (1) monostatic RCS of cube of side 50λ (100λ), (2) beam steering of array of 40 by 40 microstrip patch antennas at 9.2 GHz, and (3) beam steering of 4 by 4 patch antennas at 2 GHz (5 GHz), placed on a 19-m long helicopter.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"22 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":"122447186","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.2011.6047331
F. Obelleiro, J. M. Taboada, M. Araújo, L. Landesa
We present some integral-equation approaches for the accurate solution of different problems in computational electromagnetics. First, an efficient MPI/OpenMP parallel implementation of MLFMA-FFT algorithm is presented for the solution of large-scale metallic conducting bodies. By combining the high scalability of FMM-FFT with the high efficiency of the MLFMA, a challenging problem with more than one billion unknowns was solved using a parallel supercomputer. Second, looking for the extension of these rigorous approaches to the new problems devised with the advent of nanoscience and nanotechnology, the integral-equation method was successfully applied to the solution of left-handed metamaterials and plasmonic nanostructures. Numerical examples are presented that confirm the validity and versatility of this approach for the accurate resolution of problems in the context of leading-edge nanoscience and nanotechnology applications.
{"title":"Computational electromagnetic solutions for large-scale conductors, left-handed metamaterials and plasmonic nanostructures","authors":"F. Obelleiro, J. M. Taboada, M. Araújo, L. Landesa","doi":"10.1109/CEM.2011.6047331","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047331","url":null,"abstract":"We present some integral-equation approaches for the accurate solution of different problems in computational electromagnetics. First, an efficient MPI/OpenMP parallel implementation of MLFMA-FFT algorithm is presented for the solution of large-scale metallic conducting bodies. By combining the high scalability of FMM-FFT with the high efficiency of the MLFMA, a challenging problem with more than one billion unknowns was solved using a parallel supercomputer. Second, looking for the extension of these rigorous approaches to the new problems devised with the advent of nanoscience and nanotechnology, the integral-equation method was successfully applied to the solution of left-handed metamaterials and plasmonic nanostructures. Numerical examples are presented that confirm the validity and versatility of this approach for the accurate resolution of problems in the context of leading-edge nanoscience and nanotechnology applications.","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":"127853451","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.2011.6047318
E. Ubeda, J. Tamayo, J. Rius
Vie present new implementations in the method of moments of two types of second-kind integral equations: (i) the recently proposed electric-magnetic field integral equation (EMFIE) for perfectly conducting objects, and (ii) the Müller formulation for homogeneous or piecewise homogeneous dielectric objects. We adopt the Taylor-orthogonal basis functions, a recently presented set of facet-oriented basis functions, which arise from the Taylor's expansion of the current at the centroids of the discretization triangles.
{"title":"Divergence-Taylor-orthogonal basis functions for the discretization of second-kind surface integral equations in the method of moments","authors":"E. Ubeda, J. Tamayo, J. Rius","doi":"10.1109/CEM.2011.6047318","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047318","url":null,"abstract":"Vie present new implementations in the method of moments of two types of second-kind integral equations: (i) the recently proposed electric-magnetic field integral equation (EMFIE) for perfectly conducting objects, and (ii) the Müller formulation for homogeneous or piecewise homogeneous dielectric objects. We adopt the Taylor-orthogonal basis functions, a recently presented set of facet-oriented basis functions, which arise from the Taylor's expansion of the current at the centroids of the discretization triangles.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"47 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":"115109085","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.2011.6047325
T. Eibert, H. Buddendick
Image formation by inverse synthetic aperture radar (ISAR) methods is one of the most advanced approaches to explore the scattering or radiation properties of a finite sized object. ISAR imaging is based on the coherent processing of radar signals, which are collected for a range of observation angles and for a certain range of frequencies. In a radar experiment, it is mandatory that ISAR works with the waves scattered from the observed object. In contrast, in simulation based considerations there is no need to compute the scattered waves explicitly. It is rather recommended to directly generate the ISAR image with the induced currents on the targets, which are usually available in an electromagnetic simulation, e.g., by the shooting and bouncing rays (SBR) techniques utilizing physical optics (PO). Instead of computing the scattered or radiated fields from the real or equivalent currents the radiation integral is directly inserted into the imaging integral and by interchanging the integration orders, the imaging point spread function can be generated. Consequently, the image formation is reduced to a convolution of the found point spread function with the current distribution. A concise vectorial formulation of this well-known methodology is presented together with a discussion of important properties. The general case of 3-D ISAR imaging is considered, which is also specialized to the 2-D situation. The point spread functions are analytically derived for narrow angle and narrow bandwidth imaging, where a bistatic observation range symmetrically arranged around one incident direction is considered. The resulting images can thus be assumed as a good approximation of monostatic images, which are often desired. Various examples of 2-D and 3-D images for complex metallic objects such as automobiles are shown, which have been obtained from the surface currents of an SBR field solver. Implementation issues related to the required interpolations as well as the efficient realization of the SBR simulations are discussed.
{"title":"Direct image formation with current distributions generated by shooting and bouncing rays","authors":"T. Eibert, H. Buddendick","doi":"10.1109/CEM.2011.6047325","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047325","url":null,"abstract":"Image formation by inverse synthetic aperture radar (ISAR) methods is one of the most advanced approaches to explore the scattering or radiation properties of a finite sized object. ISAR imaging is based on the coherent processing of radar signals, which are collected for a range of observation angles and for a certain range of frequencies. In a radar experiment, it is mandatory that ISAR works with the waves scattered from the observed object. In contrast, in simulation based considerations there is no need to compute the scattered waves explicitly. It is rather recommended to directly generate the ISAR image with the induced currents on the targets, which are usually available in an electromagnetic simulation, e.g., by the shooting and bouncing rays (SBR) techniques utilizing physical optics (PO). Instead of computing the scattered or radiated fields from the real or equivalent currents the radiation integral is directly inserted into the imaging integral and by interchanging the integration orders, the imaging point spread function can be generated. Consequently, the image formation is reduced to a convolution of the found point spread function with the current distribution. A concise vectorial formulation of this well-known methodology is presented together with a discussion of important properties. The general case of 3-D ISAR imaging is considered, which is also specialized to the 2-D situation. The point spread functions are analytically derived for narrow angle and narrow bandwidth imaging, where a bistatic observation range symmetrically arranged around one incident direction is considered. The resulting images can thus be assumed as a good approximation of monostatic images, which are often desired. Various examples of 2-D and 3-D images for complex metallic objects such as automobiles are shown, which have been obtained from the surface currents of an SBR field solver. Implementation issues related to the required interpolations as well as the efficient realization of the SBR simulations are discussed.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"119 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":"133487304","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.2011.6047329
M. Zoppi, C. Dedeban, C. Pichot, S. Selleri, G. Pelosi
This paper describes the development of an antenna synthesis procedure for 2-D array configurations using an inverse scattering algorithm based on a conjugate gradient method.
本文描述了一种基于共轭梯度法的逆散射算法的二维阵列天线合成程序的发展。
{"title":"Optimal location of multi-antenna systems using a conjugate gradient method","authors":"M. Zoppi, C. Dedeban, C. Pichot, S. Selleri, G. Pelosi","doi":"10.1109/CEM.2011.6047329","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047329","url":null,"abstract":"This paper describes the development of an antenna synthesis procedure for 2-D array configurations using an inverse scattering algorithm based on a conjugate gradient method.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"23 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":"121387389","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.2011.6047350
R. Kastner
In many applications, it may be advisable to "tear apart" the computational domain into several sub-domains separated by "seams," each one treated separately. The sub-domains are then sewn back together at appropriate stages of the computation. We present three main diakoptic strategies, as described below.
{"title":"Finite-difference time-domain diakoptic strategies","authors":"R. Kastner","doi":"10.1109/CEM.2011.6047350","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047350","url":null,"abstract":"In many applications, it may be advisable to \"tear apart\" the computational domain into several sub-domains separated by \"seams,\" each one treated separately. The sub-domains are then sewn back together at appropriate stages of the computation. We present three main diakoptic strategies, as described below.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"29 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":"127199241","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.2011.6047351
Kai Yang, F. Wei, A. Yılmaz
The effectiveness of multigrid and fast Fourier transform (FFT) based methods are investigated for accelerating the solution of volume integral equations encountered in bioelectromagnetics (BIOEM) analysis. The typical BIOEM simulation is in the mixed-frequency regime of analysis because the field variations in the simulation domain are dictated by a combination of the free space wavelength, geometrical features, and the wavelengths/skin depths in tissues. In this case, multigrid-based methods (when appropriately truncated at high-frequency levels) can achieve O(N) complexity that is asymptotically superior to the O(NlogN) complexity of FFT-based ones. Nevertheless, the constant in front of their asymptotic complexity estimate is larger and their accuracy-efficiency tradeoffs are different. Numerical experiments are performed to compare these methods and the results show that multigrid-based methods begin to outperform FFT-based ones for N∼103.
{"title":"Truncated multigrid versus pre-corrected FFT/AIM for bioelectromagnetics: When is O(N) better than O(NlogN)?","authors":"Kai Yang, F. Wei, A. Yılmaz","doi":"10.1109/CEM.2011.6047351","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047351","url":null,"abstract":"The effectiveness of multigrid and fast Fourier transform (FFT) based methods are investigated for accelerating the solution of volume integral equations encountered in bioelectromagnetics (BIOEM) analysis. The typical BIOEM simulation is in the mixed-frequency regime of analysis because the field variations in the simulation domain are dictated by a combination of the free space wavelength, geometrical features, and the wavelengths/skin depths in tissues. In this case, multigrid-based methods (when appropriately truncated at high-frequency levels) can achieve O(N) complexity that is asymptotically superior to the O(NlogN) complexity of FFT-based ones. Nevertheless, the constant in front of their asymptotic complexity estimate is larger and their accuracy-efficiency tradeoffs are different. Numerical experiments are performed to compare these methods and the results show that multigrid-based methods begin to outperform FFT-based ones for N∼103.","PeriodicalId":169588,"journal":{"name":"CEM'11 Computational Electromagnetics International Workshop","volume":"29 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120941423","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.2011.6047324
A. Zamanifekri, A. B. Smolders
In this study, a method for amplitude and phase constrained focal plane array pattern synthesis based on the intersection approach and Gram-Schmidt orthogonalization is presented. A new formulation for alternation projection, which leads to a efficient and simple algorithm, is given. The basic idea of the method is to utilize Gram-Schmidt orthogonalization as the projection operator in the iteration step of the alternating projection method. A number of examples are presented to highlight various aspects of the proposed method.
{"title":"Fast pattern synthesis for focal plane arrays using an iterative Gram-Schmidt orthogonalization","authors":"A. Zamanifekri, A. B. Smolders","doi":"10.1109/CEM.2011.6047324","DOIUrl":"https://doi.org/10.1109/CEM.2011.6047324","url":null,"abstract":"In this study, a method for amplitude and phase constrained focal plane array pattern synthesis based on the intersection approach and Gram-Schmidt orthogonalization is presented. A new formulation for alternation projection, which leads to a efficient and simple algorithm, is given. The basic idea of the method is to utilize Gram-Schmidt orthogonalization as the projection operator in the iteration step of the alternating projection method. A number of examples are presented to highlight various aspects of the proposed method.","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":"129261114","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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