Download or read book Electromagnetic Scattering and Material Characterization written by Abbas Omar and published by Artech House. This book was released on 2011 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Near field Scattering Tomography System for Object Imaging and Material Characterization written by Shahed Shahir and published by . This book was released on 2015 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Advanced Electromagnetic Models for Materials Characterization and Nondestructive Evaluation written by Harold A Sabbagh and published by Springer Nature. This book was released on 2021-04-20 with total page 351 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Transient Electromagnetic Scattering Analysis of Homogeneous Material Bodies written by Ramin Aghajafari and published by . This book was released on 2006 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Analysis of Electromagnetic Scattering by Structures Composed of Conducting and Dielectric Material written by Adriaan Jacobus Booysen and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Concepts in Electromagnetic Scattering for Particulate systems Characterization written by and published by . This book was released on 2013 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ultrasonic and Electromagnetic NDE for Structure and Material Characterization written by Tribikram Kundu and published by CRC Press. This book was released on 2016-04-19 with total page 890 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book Electromagnetic Scattering Analysis of a Three Dimensional Inhomogeneous Material Body Using the Finite Element Method written by Robert Gilman Andre and published by . This book was released on 1993 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analysis of the Three dimensional Electromagnetic Scattering from a Finite Material Strip Joined with a Perfectly Conducting Half plane written by Joyce A. Fichtner and published by . This book was released on 1991 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Acoustic and Electromagnetic Scattering Analysis Using Discrete Sources written by Adrian Doicu and published by Academic Press. This book was released on 2000-07-06 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: The discrete sources method is an efficient and powerful tool for solving a large class of boundary-value problems in scattering theory. A variety of numerical methods for discrete sources now exist. In this book, the authors unify these formulations in the context of the so-called discrete sources method. Comprehensive presentation of the discrete sources method Original theory - an extension of the conventional null-field method using discrete sources Practical examples that demonstrate the efficiency and flexibility of elaborated methods (scattering by particles with high aspect ratio, rough particles, nonaxisymmetric particles, multiple scattering) List of discrete sources programmes available via the Internet

Download or read book Electromagnetic Scattering Analysis of Arbitrarily Shaped Material Cylinder by FEM BEM Method written by M. D. Deshpande and published by . This book was released on 1996 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: A hybrid method that combines the finite element method (FEM) and the boundary element method (BEM) is developed to analyze electromagnetic scattering from arbitrarily shaped material cylinders. By this method, the material cylinder is first enclosed by a fictitious boundary. Maxwell's equations are then solved by FEM inside and by BEM outside the boundary. Electromagnetic scattering from several arbitrarily shaped material cylinders is computed and compared with results obtained by other numerical techniques.

Download or read book Electromagnetic Material Characterization Using a Partially Filled Rectangular Waveguide written by Andrew Eric Bogle and published by . This book was released on 2004 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Magnetic Measurement Techniques for Materials Characterization written by Victorino Franco and published by Springer Nature. This book was released on 2021-09-28 with total page 814 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses the most commonly used techniques for characterizing magnetic material properties and their applications. It provides a comprehensive and easily digestible collection and review of magnetic measurement techniques. It also examines the underlying operating principles and techniques of magnetic measurements, and presents current examples where such measurements and properties are relevant. Given the pervasive nature of magnetic materials in everyday life, this book is a vital resource for both professionals and students wishing to deepen their understanding of the subject.

Download or read book A Numerical Analysis of Electromagnetic Scattering from Two Dimensional Edge Terminations written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-17 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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)...

Download or read book Multiple Electromagnetic Scattering Within and Electrical Characterization of 3D Printed Dielectrics written by Hanxiong Hu and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Additive manufacturing (AM) is an increasingly popular method for manufacturing antennas and other microwave components to achieve rapid prototyping and design flexibility at a low cost. Embedding AM antenna elements or radio-frequency (RF) and microwave components within structures will further reduce weight and improve system integration, e.g., embedding a tracking antenna within the wing of an unmanned aerial vehicle. For the technology to be universally adopted for direct product manufacturing with AM technologies, a better understanding of the AM material properties is required. An analytical model was developed to simulated the propagation of electromagnetic wave in a dielectric substrate with an air--dielectric interface and a cylindrical air-filled cavity. The scattering interactions were described using expansion of cylindrical wave functions, and solved using the tangential electromagnetic field components of the boundary conditions. Multiple scattering between the air--dielectric interface and the cylindrical air-filled cavity were then simplified by mirroring the cylindrical air-filled cavity, and then transformed with the use of Hankel functions, summing the multiple scattering contributions, and recalculating the scattering. The surface electromagnetic fields were acquired and compared with results from FEKO to demonstrate the relevance of the scattering method. The two-microstrip-line method and the two-port transmission line method with waveguides were used to measure the permittivity of AM and synthetic materials for fabrication RF components. The results of the two methods showed they are qualitatively accurate when compared with reference values of bulk commercial substrates, and can be used to acquire permittivity of AM-built and synthetic materials for AM microwave components. By taking advantages of AM dielectric substrates, how infill density and infill pattern impact the permittivity of AM dielectric substrates were investigated. A linear relationship between infill density of the rectangular pattern and the substrate permittivity was found. The permittivity data were applied to the design of a rectangular patch antenna for use in 2.5-GHz WiMAX band. The fabricated antenna with AM showed good agreement with simulation results, which was characterized using a vector network analyzer. In addition, power dividers and filters were designed and fabricated by printing silver nanoparticle ink on a polyimide substrate, an AM thermoplastic polyurethane (TPU), and a synthetic material substrate. The theory and method developed for characterizing AM dielectric substrates can be flexibly applied to the design and fabrication of AM microwave components. The goal of the research was to characterize AM material and utilize the measured permittivity in the design of AM microwave components.

Download or read book Electromagnetic Scattering Analysis of Arbitrarily Shaped Material Cylinder by Fem Bem Method written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-02 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: A hybrid method that combines the finite element method (FEM) and the boundary element method (BEM) is developed to analyze electromagnetic scattering from arbitrarily shaped material cylinders. By this method, the material cylinder is first enclosed by a fictitious boundary. Maxwell's equations are then solved by FEM inside and by BEM outside the boundary. Electromagnetic scattering from several arbitrarily shaped material cylinders is computed and compared with results obtained by other numerical techniques. Deshpande, M. D. and Cockrell, C. R. and Reddy, C. J. Langley Research Center RTOP 505-64-52-04...

Download or read book Radiation and Scattering of Electromagnetic Waves at the Surfaces of Composite Materials written by Chaoli Gu and published by . This book was released on 1993 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: