Method of Moments for 2D Scattering Problems

Author: Christophe Bourlier
Publisher: John Wiley & Sons
ISBN: 1118648684
Format: PDF, Mobi
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Electromagnetic wave scattering from randomly rough surfaces inthe presence of scatterers is an active, interdisciplinary area ofresearch with myriad practical applications in fields such asoptics, acoustics, geoscience and remote sensing. In this book, the Method of Moments (MoM) is applied to compute thefield scattered by scatterers such as canonical objects (cylinderor plate) or a randomly rough surface, and also by an object aboveor below a random rough surface. Since the problem is considered tobe 2D, the integral equations (IEs) are scalar and only the TE(transverse electric) and TM (transverse magnetic) polarizationsare addressed (no cross-polarizations occur). In Chapter 1, the MoMis applied to convert the IEs into a linear system, while Chapter 2compares the MoM with the exact solution of the field scattered bya cylinder in free space, and with the Physical Optics (PO)approximation for the scattering from a plate in free space.Chapter 3 presents numerical results, obtained from the MoM, of thecoherent and incoherent intensities scattered by a random roughsurface and an object below a random rough surface. The finalchapter presents the same results as in Chapter 3, but for anobject above a random rough surface. In these last two chapters,the coupling between the two scatterers is also studied in detailby inverting the impedance matrix by blocks. Contents 1. Integral Equations for a Single Scatterer: Method of Momentsand Rough Surfaces. 2. Validation of the Method of Moments for a SingleScatterer. 3. Scattering from Two Illuminated Scatterers. 4. Scattering from Two Scatterers Where Only One isIlluminated. Appendix. Matlab Codes. About the Authors Christophe Bourlier works at the IETR (Institutd’Electronique et de Télécommunications de Rennes)laboratory at Polytech Nantes (University of Nantes, France) aswell as being a Researcher at the French National Center forScientific Research (CNRS) on electromagnetic wave scattering fromrough surfaces and objects for remote sensing applications andradar signatures. He is the author of more than 160 journalarticles and conference papers. Nicolas Pinel is currently working as a Research Engineer at theIETR laboratory at Polytech Nantes and is about to join AlyotechTechnologies in Rennes, France. His research interests are in theareas of radar and optical remote sensing, scattering andpropagation. In particular, he works on asymptotic methods ofelectromagnetic wave scattering from random rough surfaces andlayers. Gildas Kubické is in charge of the “Expertise inelectroMagnetism and Computation” (EMC) laboratory at the DGA(Direction Générale de l’Armement), French Ministryof Defense, where he works in the field of radar signatures andelectromagnetic stealth. His research interests includeelectromagnetic scattering and radar cross-section modeling.

Numerical Analysis for Electromagnetic Integral Equations

Author: Karl F. Warnick
Publisher: Artech House
ISBN: 1596933348
Format: PDF, ePub, Docs
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This unique volume is the first book on integral equation-based methods that combines quantitative formulas for predicting numerical simulation accuracy together with rigorous error estimates and results for dozens of actual electromagnetics and wave propagation problems. You get the latest insights on accuracy-improving methods like regularization and error-increasing effects such as edge singularities and resonance, along with full details on how to determine mesh density, choice of basis functions, and other parameters needed to optimize any numerical simulation.

Electromagnetic Scattering Using the Iterative Multiregion Technique

Author: Mohamed Hassan Al Sharkawy
Publisher: Morgan & Claypool Publishers
ISBN: 1598295357
Format: PDF, Docs
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In this work, an iterative approach using the finite difference frequency domain method is presented to solve the problem of scattering from large-scale electromagnetic structures. The idea of the proposed iterative approach is to divide one computational domain into smaller subregions and solve each subregion separately. Then the subregion solutions are combined iteratively to obtain a solution for the complete domain. As a result, a considerable reduction in the computation time and memory is achieved. This procedure is referred to as the iterative multiregion (IMR) technique.Different enhancement procedures are investigated and introduced toward the construction of this technique. These procedures are the following: 1) a hybrid technique combining the IMR technique and a method of moment technique is found to be efficient in producing accurate results with a remarkable computer memory saving; 2) the IMR technique is implemented on a parallel platform that led to a tremendous computational time saving; 3) together, the multigrid technique and the incomplete lower and upper preconditioner are used with the IMR technique to speed up the convergence rate of the final solution, which reduces the total computational time. Thus, the proposed iterative technique, in conjunction with the enhancement procedures, introduces a novel approach to solving large open-boundary electromagnetic problems including unconnected objects in an efficient and robust way.Contents: Basics of the FDFD Method / IMR Technique for Large-Scale Electromagnetic Scattering Problems: 3D Case / IMR Technique for Large-Scale Electromagnetic Scattering Problems: 2D Case / The IMR Algorithm Using a Hybrid FDFD and Method of Moments Technique / Parallelization of the Iterative Multiregion Technique / Combined Multigrid Technique and IMR Algorithm / Concluding Remarks / Appendices

MMSE Based Algorithm for Joint Signal Detection Channel and Noise Variance Estimation for OFDM Systems

Author: Vincent Savaux
Publisher: John Wiley & Sons
ISBN: 1119007909
Format: PDF, Docs
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This book presents an algorithm for the detection of an orthogonal frequency division multiplexing (OFDM) signal in a cognitive radio context by means of a joint and iterative channel and noise estimation technique. Based on the minimum mean square criterion, it performs an accurate detection of a user in a frequency band, by achieving a quasi-optimal channel and noise variance estimation if the signal is present, and by estimating the noise level in the band if the signal is absent. Organized into three chapters, the first chapter provides the background against which the system model is presented, as well as some basics concerning the channel statistics and the transmission of an OFDM signal over a multipath channel. In Chapter 2, the proposed iterative algorithm for the noise variance and the channel estimation is detailed, and in Chapter 3, an application of the algorithm for the free-band detection is proposed. In both Chapters 2 and 3, the principle of the algorithm is presented in a simple way, and more elaborate developments are also provided. The different assumptions and assertions in the developments and the performance of the proposed method are validated through simulations, and compared to methods of the scientific literature

Essentials of Computational Electromagnetics

Author: Xin-Qing Sheng
Publisher: John Wiley & Sons
ISBN: 0470829656
Format: PDF, ePub, Mobi
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Essentials of Computational Electromagnetics provides an in-depth introduction of the three main full-wave numerical methods in computational electromagnetics (CEM); namely, the method of moment (MoM), the finite element method (FEM), and the finite-difference time-domain (FDTD) method. Numerous monographs can be found addressing one of the above three methods. However, few give a broad general overview of essentials embodied in these methods, or were published too early to include recent advances. Furthermore, many existing monographs only present the final numerical results without specifying practical issues, such as how to convert discretized formulations into computer programs, and the numerical characteristics of the computer programs. In this book, the authors elaborate the above three methods in CEM using practical case studies, explaining their own research experiences along with a review of current literature. A full analysis is provided for typical cases, including characteristics of numerical methods, helping beginners to develop a quick and deep understanding of the essentials of CEM. Outlines practical issues, such as how to convert discretized formulations into computer programs Gives typical computer programs and their numerical characteristics along with line by line explanations of programs Uses practical examples from the authors' own work as well as in the current literature Includes exercise problems to give readers a better understanding of the material Introduces the available commercial software and their limitations This book is intended for graduate-level students in antennas and propagation, microwaves, microelectronics, and electromagnetics. This text can also be used by researchers in electrical and electronic engineering, and software developers interested in writing their own code or understanding the detailed workings of code. Companion website for the book: www.wiley.com/go/sheng/cem

Knowledge Discovery and Data Mining

Author: Honghua Tan
Publisher: Springer Science & Business Media
ISBN: 364227708X
Format: PDF, ePub
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The volume includes a set of selected papers extended and revised from the 4th International conference on Knowledge Discovery and Data Mining, March 1-2, 2011, Macau, Chin. This Volume is to provide a forum for researchers, educators, engineers, and government officials involved in the general areas of knowledge discovery and data mining and learning to disseminate their latest research results and exchange views on the future research directions of these fields. 108 high-quality papers are included in the volume.

Electromagnetic Fields in Mechatronics Electrical and Electronic Engineering

Author: A. Krawczyk
Publisher: IOS Press
ISBN: 1607501821
Format: PDF, ePub, Docs
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More and more researchers engage into investigation of electromagnetic applications, especially these connected with mechatronics, information technologies, medicine, biology and material sciences. It is readily seen when looking at the content of the book that computational techniques, which were under development during the last three decades and are still being developed, serve as good tools for discovering new electromagnetic phenomena. It means that the field of computational electromagnetics belongs to an application area rather than to a research area. This publication aims at joining theory and practice, thus the majority of papers are deeply rooted in engineering problems, being simultaneously of high theoretical level. The editors hope to touch the heart of the matter in electromagnetism. The book focuses on the following issues: Computational Electromagnetics; Electromagnetic Engineering; Coupled Field and Special Applications; Micro- and Special Devices; Bioelectromagnetics and Electromagnetic Hazard; and Magnetic Material Modeling.

Parallel Solution of Integral Equation Based EM Problems in the Frequency Domain

Author: Y. Zhang
Publisher: John Wiley & Sons
ISBN: 9780470495087
Format: PDF, Kindle
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A step-by-step guide to parallelizing cem codes The future of computational electromagnetics is changing drastically as the new generation of computer chips evolves from single-core to multi-core. The burden now falls on software programmers to revamp existing codes and add new functionality to enable computational codes to run efficiently on this new generation of multi-core CPUs. In this book, you'll learn everything you need to know to deal with multi-core advances in chip design by employing highly efficient parallel electromagnetic code. Focusing only on the Method of Moments (MoM), the book covers: In-Core and Out-of-Core LU Factorization for Solving a Matrix Equation A Parallel MoM Code Using RWG Basis Functions and ScaLAPACK-Based In-Core and Out-of-Core Solvers A Parallel MoM Code Using Higher-Order Basis Functions and ScaLAPACK-Based In-Core and Out-of-Core Solvers Turning the Performance of a Parallel Integral Equation Solver Refinement of the Solution Using the Conjugate Gradient Method A Parallel MoM Code Using Higher-Order Basis Functions and Plapack-Based In-Core and Out-of-Core Solvers Applications of the Parallel Frequency Domain Integral Equation Solver Appendices are provided with detailed information on the various computer platforms used for computation; a demo shows you how to compile ScaLAPACK and PLAPACK on the Windows® operating system; and a demo parallel source code is available to solve the 2D electromagnetic scattering problems. Parallel Solution of Integral Equation-Based EM Problems in the Frequency Domain is indispensable reading for computational code designers, computational electromagnetics researchers, graduate students, and anyone working with CEM software.