Electromagnetic Scattering and Material Characterization

Electromagnetic Scattering and Material Characterization
Author: Abbas Omar
Publisher: Artech House
Total Pages: 314
Release: 2011
Genre: Science
ISBN: 1596932171

Download Electromagnetic Scattering and Material Characterization Book in PDF, Epub and Kindle

Based on the authorOCOs more-than 30 years of experience, this first-of-its-kind volume presents a comprehensive and systematic analysis of electromagnetic fields and their scattering by material objects. The book considers all three categories of scattering environments commonly used for material measurements OCo unbounded regions, waveguides, and cavity resonators. The book covers such essential topics as electromagnetic field propagation, radiation, and scattering, containing mathematically rigorous approaches for the computation of electromagnetic fields and the explanation of their behavior. Moreover, the book explore new measurement techniques for material characterization most of which have never been published before. This detailed reference is packed with over 400 equations.

Advanced Electromagnetic Models for Materials Characterization and Nondestructive Evaluation

Advanced Electromagnetic Models for Materials Characterization and Nondestructive Evaluation
Author: Harold A Sabbagh
Publisher: Springer Nature
Total Pages: 351
Release: 2021-04-20
Genre: Science
ISBN: 303067956X

Download Advanced Electromagnetic Models for Materials Characterization and Nondestructive Evaluation Book in PDF, Epub and Kindle

This book expands on the subject matter of ’Computational Electromagnetics and Model-Based Inversion: A Modern Paradigm for Eddy-Current Nondestructive Evaluation.’ It includes (a) voxel-based inversion methods, which are generalizations of model-based algorithms; (b) a complete electromagnetic model of advanced composites (and other novel exotic materials), stressing the highly anisotropic nature of these materials, as well as giving a number of applications to nondestructive evaluation; and (c) an up-to-date discussion of stochastic integral equations and propagation-of-uncertainty models in nondestructive evaluation. As such, the book combines research started twenty-five years ago in advanced composites and voxel-based algorithms, but published in scattered journal articles, as well as recent research in stochastic integral equations. All of these areas are of considerable interest to the aerospace, nuclear power, civil infrastructure, materials characterization and biomedical industries. The book covers the topic of computational electromagnetics in eddy-current nondestructive evaluation (NDE) by emphasizing three distinct topics: (a) fundamental mathematical principles of volume-integral equations as a subset of computational electromagnetics, (b) mathematical algorithms applied to signal-processing and inverse scattering problems, and (c) applications of these two topics to problems in which real and model data are used. It is therefore more than an academic exercise and is valuable to users of eddy-current NDE technology in industries as varied as nuclear power, aerospace, materials characterization and biomedical imaging.

Electromagnetic Scattering in Disperse Media

Electromagnetic Scattering in Disperse Media
Author: Victor A. Babenko
Publisher: Springer Science & Business Media
Total Pages: 474
Release: 2003-09-12
Genre: Nature
ISBN: 9783540436492

Download Electromagnetic Scattering in Disperse Media Book in PDF, Epub and Kindle

This is the first book devoted specifically to the problem of light scattering and absorption by inhomogeneous and anisotropic spherical particles. Unlike other books in the field, Electromagnetic Scattering in Disperse Media pays considerable attention to various aspects of light absorption inside particles, including internal field distributions, MDR resonances, and absorption in restricted regions inside particles. It contains many results (and more than 100 figures) computed for polydisperse particle systems and algorithms and provides the possibility to use them (web site). Although the main emphasis is given to optical properties of atmospheric aerosol, the book also deals with many other practical applications involving inhomogeneous and anisotropic particles

Near-field Scattering Tomography System for Object Imaging and Material Characterization

Near-field Scattering Tomography System for Object Imaging and Material Characterization
Author: Shahed Shahir
Publisher:
Total Pages: 115
Release: 2015
Genre: Diagnostic imaging
ISBN:

Download Near-field Scattering Tomography System for Object Imaging and Material Characterization Book in PDF, Epub and Kindle

Electromagnetic inverse scattering based permittivity profile estimation is one of the most promising techniques for object imaging and material characterization. Electromagnetic scattering tomography at the microwaves and THz frequency range can be used for medical imaging since all parts of the human body are naturally non-magnetic and dielectric, and millimeter and submillimeter waves can penetrate inside dielectrics. However, because electromagnetic inverse scattering problems are ill-conditioned and ill-posed, electromagnetic inverse scattering has not yet been successfully implemented in many potential application areas, particularly in clinical imaging. This dissertation presents a new formulation, a novel concept, and an effective implementation procedure to alleviate these problems and hopefully shorten the gap between the current state-of-the-art and real applications and to improve the electromagnetic inverse scattering technique in general. The major contribution of this dissertation is a new formulation of the electromagnetic inverse scattering problem based on a discrete modal analysis. To do so, the scattered electric field and the volume equivalent current source (VECS) are projected into a subspace spanned by the singular vectors obtained from the spatial Green's function of the near-field scattering tomography system representation. Differentiating between the significant singular values and the less significant one is an important step. The scattered electric field coefficients are bounded and stable, while the VECS coefficients are not stable in the new subspaces since the singular values of the Green's function modal representation start decaying very rapidly beyond a certain threshold. Minimizing the mean square error of the estimated scattered electric field or the estimated permittivity profile is used to find the threshold. The singular vectors below the threshold are considered as the radiating singular vectors, so the VECS projected into the radiating singular vectors are called the radiating VECS, and the contrast factor calculated by the radiating VECS are called the radiating contrast factor. The expected radiating contrast factor is constructed by repeating the measurements at different angles and/or frequencies. Then, the radiating permittivity profile and radiating conductivity profile of the object under-test (OUT) are obtained. In fact, the radiating permittivity profile carries important information about the OUT. The experimental results show that the OUT boundary information is embedded into the radiating permittivity profile, and the boundary of the OUT is effectively determined by using the radiating permittivity profile of region of interest. The second and foremost contribution of this dissertation is proposing a novel approach for solving the electromagnetic inverse scattering problem to make the solution unique by introducing the non-radiating contrast factor and the non-radiating objective function. Decomposing the permittivity into two complementary parts, the radiating permittivity profile and the non-radiating permittivity profile, improves the ill-posedness nature of the electromagnetic inverse scattering problem. Since the radiating permittivity profile is visible, and the non-radiating permittivity profile is invisible from the view point of the outside observer, in the first step, the boundary of the OUT is determined by using the aforementioned radiating permittivity profile obtained from the measurement outside the OUT. Then, the electromagnetic properties of the OUT are estimated - with sufficient accuracy - by minimizing the non-radiating objective function. The electromagnetic properties of the low-contrast and high-contrast OUTs are successfully estimated by the proposed approach, and the approach performance is also verified in a noisy environment through extensive simulations. The third major contribution of this dissertation is the introduction of a new planar near-field scattering tomography (PNFST) system. The PNFST system calibration and operational procedures are discussed. The proposed PNFST system is the first scattering tomography system implemented at the W-band frequency range in free space. Eliminating the multipath effects in the system enable us to make the incident field measurement process fast and quite effective since the field is measured in the absence of the scatterer only once. The PNFST system reconstructs the radiating permittivity profile of the region of interest, determines the boundary of the OUT, characterizes the material, and provides the electromagnetic properties of the low-contrast and high-contrast OUT. The experimental results validate the performance of the implemented PNFST system.

Ultrasonic and Electromagnetic NDE for Structure and Material Characterization

Ultrasonic and Electromagnetic NDE for Structure and Material Characterization
Author: Tribikram Kundu
Publisher: CRC Press
Total Pages: 890
Release: 2016-04-19
Genre: Science
ISBN: 1466570474

Download Ultrasonic and Electromagnetic NDE for Structure and Material Characterization Book in PDF, Epub and Kindle

Most books on nondestructive evaluation (NDE) focus either on the theoretical background or on advanced applications. Bridging the gap between the two, Ultrasonic and Electromagnetic NDE for Structure and Material Characterization: Engineering and Biomedical Applications brings together the principles, equations, and applications of ultrasonic and

Inverse Acoustic and Electromagnetic Scattering Theory

Inverse Acoustic and Electromagnetic Scattering Theory
Author: David Colton
Publisher: Springer Science & Business Media
Total Pages: 347
Release: 2013-03-09
Genre: Science
ISBN: 3662035375

Download Inverse Acoustic and Electromagnetic Scattering Theory Book in PDF, Epub and Kindle

This book is devoted to the mathematical and numerical analysis of the inverse scattering problem for acoustic and electromagnetic waves. The second edition includes material on Newton’s method for the inverse obstacle problem, an elegant proof of uniqueness for the inverse medium problem, a discussion of the spectral theory of the far field operator and a method for determining the support of an inhomogeneous medium from far field data.

A Numerical Analysis of Electromagnetic Scattering from Two-Dimensional Edge Terminations

A Numerical Analysis of Electromagnetic Scattering from Two-Dimensional Edge Terminations
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
Total Pages: 120
Release: 2018-07-17
Genre:
ISBN: 9781722905309

Download A Numerical Analysis of Electromagnetic Scattering from Two-Dimensional Edge Terminations Book in PDF, Epub and Kindle

Several techniques that influence the low frequency scattering from penetrable edge terminations are evaluated using a hybrid finite element and boundary element method code. The edge terminations consist of a dielectric skin forming an exterior shape with an internal conducting bulkhead. Some of the techniques considered are bulkhead shaping, internal material loading, placement of resistive cards, and the placement of lossy dielectric material rods. The intent of the various treatments is to find a combination or combinations that influence(s) the backscattered field to acceptable levels over a range of frequencies for both transverse magnetic and transverse electric polarizations. Gray, B. E. and Dominek, A. K. and Wang, N. Glenn Research Center NUMERICAL ANALYSIS; MATHEMATICAL MODELS; ELECTROMAGNETIC SCATTERING; BOUNDARY ELEMENT METHOD; FINITE ELEMENT METHOD; TWO DIMENSIONAL MODELS; EDGES; DIELECTRICS; BULKHEADS; BACKSCATTERING; POLARIZED ELECTROMAGNETIC RADIATION; GRID GENERATION (MATHEMATICS)...