Selected Asymptotic Methods with Applications to Electromagnetics and Antennas
Selected Asymptotic Methods with Applications to Electromagnetics and Antennas

Author: George Fikioris

Publisher: Springer Nature

Published: 2022-06-01

Total Pages: 187

ISBN-13: 3031017161

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This book describes and illustrates the application of several asymptotic methods that have proved useful in the authors' research in electromagnetics and antennas. We first define asymptotic approximations and expansions and explain these concepts in detail. We then develop certain prerequisites from complex analysis such as power series, multivalued functions (including the concepts of branch points and branch cuts), and the all-important gamma function. Of particular importance is the idea of analytic continuation (of functions of a single complex variable); our discussions here include some recent, direct applications to antennas and computational electromagnetics. Then, specific methods are discussed. These include integration by parts and the Riemann-Lebesgue lemma, the use of contour integration in conjunction with other methods, techniques related to Laplace's method and Watson's lemma, the asymptotic behavior of certain Fourier sine and cosine transforms, and the Poisson summation formula (including its version for finite sums). Often underutilized in the literature are asymptotic techniques based on the Mellin transform; our treatment of this subject complements the techniques presented in our recent Synthesis Lecture on the exact (not asymptotic) evaluation of integrals.

Selected Asymptotic Methods with Applications to Electromagnetics and Antennas
Selected Asymptotic Methods with Applications to Electromagnetics and Antennas

Author: George J. Fikioris

Publisher: Morgan & Claypool

Published: 2014

Total Pages: 0

ISBN-13: 9781627050395

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This book describes and illustrates the application of several asymptotic methods that have proved useful in the authors' research in electromagnetics and antennas. We first define asymptotic approximations and expansions and explain these concepts in detail. We then develop certain prerequisites from complex analysis such as power series, multivalued functions (including the concepts of branch points and branch cuts), and the all-important gamma function. Of particular importance is the idea of analytic continuation (of functions of a single complex variable); our discussions here include some recent, direct applications to antennas and computational electromagnetics. Then, specific methods are discussed. These include integration by parts and the Riemann-Lebesgue lemma, the use of contour integration in conjunction with other methods, techniques related to Laplace's method and Watson's lemma, the asymptotic behavior of certain Fourier sine and cosine transforms, and the Poisson summation formula (including its version for finite sums). Often underutilized in the literature are asymptotic techniques based on the Mellin transform; our treatment of this subject complements the techniques presented in our recent Synthesis Lecture on the exact (not asymptotic) evaluation of integrals. Throughout, we provide illustrative examples. Some of them are applications to special functions of mathematical physics. Others, taken from our published research, include the application of elementary methods to develop certain simple formulas for transmission lines, examples illustrating the difficulties in solving fundamental integral equations of antenna theory, an examination of the fundamentals of the Method of Auxiliary Sources (MAS), and a study of the near fields of certain unusual types of radiators. Table of Contents: Preface / Introduction: Simple Asymptotic Approximations / Asymptotic Approximations Defined / Concepts from Complex Variables / Laplace's Method and Watson's Lemma / Integration by Parts and Asymptotics of Some Fourier Transforms / Poisson Summation Formula and Applications / Mellin-Transform Method for Asymptotic Evaluation of Integrals / More Applications to Wire Antennas / Authors' Biographies / Index

Accurate Computation of Mathieu Functions
Accurate Computation of Mathieu Functions

Author: Andrew Peterson

Publisher: Springer Nature

Published: 2022-06-01

Total Pages: 123

ISBN-13: 303101717X

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This lecture presents a modern approach for the computation of Mathieu functions. These functions find application in boundary value analysis such as electromagnetic scattering from elliptic cylinders and flat strips, as well as the analogous acoustic and optical problems, and many other applications in science and engineering. The authors review the traditional approach used for these functions, show its limitations, and provide an alternative "tuned" approach enabling improved accuracy and convergence. The performance of this approach is investigated for a wide range of parameters and machine precision. Examples from electromagnetic scattering are provided for illustration and to show the convergence of the typical series that employ Mathieu functions for boundary value analysis.

Asymptotic Multiple Scale Method in Time Domain
Asymptotic Multiple Scale Method in Time Domain

Author: Jan Awrejcewicz

Publisher: CRC Press

Published: 2022-05-10

Total Pages: 506

ISBN-13: 1000581276

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This book offers up novel research which uses analytical approaches to explore nonlinear features exhibited by various dynamic processes. Relevant to disciplines across engineering and physics, the asymptotic method combined with the multiple scale method is shown to be an efficient and intuitive way to approach mechanics. Beginning with new material on the development of cutting-edge asymptotic methods and multiple scale methods, the book introduces this method in time domain and provides examples of vibrations of systems. Clearly written throughout, it uses innovative graphics to exemplify complex concepts such as nonlinear stationary and nonstationary processes, various resonances and jump pull-in phenomena. It also demonstrates the simplification of problems through using mathematical modelling, by employing the use of limiting phase trajectories to quantify nonlinear phenomena. Particularly relevant to structural mechanics, in rods, cables, beams, plates and shells, as well as mechanical objects commonly found in everyday devices such as mobile phones and cameras, the book shows how each system is modelled, and how it behaves under various conditions. It will be of interest to engineers and professionals in mechanical engineering and structural engineering, alongside those interested in vibrations and dynamics. It will also be useful to those studying engineering maths and physics.

Wavelet Applications in Engineering Electromagnetics
Wavelet Applications in Engineering Electromagnetics

Author: Tapan K. Sarkar

Publisher: Artech House

Published: 2002

Total Pages: 367

ISBN-13: 1580532675

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Written from an engineering perspective, this unique resource describes the practical application of wavelets to the solution of electromagnetic field problems and in signal analysis with an even-handed treatment of the pros and cons. A key feature of this book is that the wavelet concepts have been described from the filter theory point of view that is familiar to researchers with an electrical engineering background. The book shows you how to design novel algorithms that enable you to solve electrically, large electromagnetic field problems using modest computational resources. It also provides you with new ideas in the design and development of unique waveforms for reliable target identification and practical radar signal analysis. The book includes more then 500 equations, and covers a wide range of topics, from numerical methods to signal processing aspects.

Chaos Theory
Chaos Theory

Author: Mykhaylo Andriychuk

Publisher: BoD – Books on Demand

Published: 2024-05-22

Total Pages: 92

ISBN-13: 1837681228

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Chaos Theory – Recent Advances, New Perspectives and Applications provides a comprehensive overview of chaos theory. It includes five chapters that discuss the history and development of chaos theory, the effectiveness of a chaos auto-associated model based on the Chebyshev-type activation function, neurite morphology, chemical self-replication, and the use of chaotic small particles to create materials with specific refractive index and magnetic permeability.

Geometrical Theory of Diffraction for Electromagnetic Waves
Geometrical Theory of Diffraction for Electromagnetic Waves

Author: Graeme L. James

Publisher: IET

Published: 1986

Total Pages: 312

ISBN-13: 9780863410628

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The purpose of the book, apart from expounding the Geometrical Theory of Diffraction (GTD) method, is to present useful formulations that can be readily applied to solve practical engineering problems.

Modern Electromagnetic Scattering Theory with Applications
Modern Electromagnetic Scattering Theory with Applications

Author: Andrey V. Osipov

Publisher: John Wiley & Sons

Published: 2017-04-17

Total Pages: 824

ISBN-13: 0470512385

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This self-contained book gives fundamental knowledge about scattering and diffraction of electromagnetic waves and fills the gap between general electromagnetic theory courses and collections of engineering formulas. The book is a tutorial for advanced students learning the mathematics and physics of electromagnetic scattering and curious to know how engineering concepts and techniques relate to the foundations of electromagnetics

Mutual Coupling Between Antennas
Mutual Coupling Between Antennas

Author: Trevor S. Bird

Publisher: John Wiley & Sons

Published: 2021-06-28

Total Pages: 484

ISBN-13: 1119564980

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Mutual Coupling Between Antennas A guide to mutual coupling between various types of antennas in arrays such as wires, apertures and microstrip patches or antennas co-sited on platforms Mutual Coupling Between Antennas explores the theoretical underpinnings of mutual coupling, offers an up-to-date description of the physical effects of mutual coupling for a variety of antennas, and contains techniques for analysing and assessing its effects. The book puts the topic in historical context, presents an integral equation approach, includes the current techniques, measurement methods, and discusses the most recent advances in the field. With contributions from noted experts on the topic, the book reviews practical aspects of mutual coupling and examines applications that clearly demonstrate where the performance is impacted both positively and negatively. Mutual Coupling Between Antennas contains information on how mutual coupling can be analysed with a wide range of methods from direct computer software using discrete methods, to integral equations and Greens function methods as well as approximate asymptotic methods. This important text: Provides a theoretical background for understanding mutual coupling between various types of antennas Describes the interaction that occurs between antennas, both planned and unplanned Explores a key aspect of arrays in any wireless, radar or sensing system operating at radio frequencies Offers a groundbreaking book on antenna mutual coupling Written for antenna engineers, technical specialists, researchers and students, Mutual Coupling Between Antennas is the first book to examine mutual coupling between various types of antennas including wires, horns, microstrip patches, MIMO antennas, co-sited antennas and arrays in planar or conformal configurations.

Electromagnetic Scattering
Electromagnetic Scattering

Author: Piergiorgio Uslenghi

Publisher: Elsevier

Published: 2012-12-02

Total Pages: 812

ISBN-13: 0323142435

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Electromagnetic Scattering is a collection of studies that aims to discuss methods, state of the art, applications, and future research in electromagnetic scattering. The book covers topics related to the subject, which includes low-frequency electromagnetic scattering; the uniform asymptomatic theory of electromagnetic edge diffraction; analyses of problems involving high frequency diffraction and imperfect half planes; and multiple scattering of waves by periodic and random distribution. Also covered in this book are topics such as theories of scattering from wire grid and mesh structures; the electromagnetic inverse problem; computational methods for transmission of waves; and developments in the use of complex singularities in the electromagnetic theory. Engineers and physicists who are interested in the study, developments, and applications of electromagnetic scattering will find the text informative and helpful.