Modeling and Analysis of Transient Processes in Open Resonant Structures: New Methods and Techniques

ISBN-13: 9780387308784 / Angielski / Twarda / 2006 / 353 str.

Yuriy K. Sirenko; Nataliya P. Yashina; Staffan Strom

Opis

The focus of electromagnetic theory is initial boundary value and boundary value problems for the Maxwell equations. Those are the initial models, from which, by applying mathematical methods, we should extract physical results. The modern computer-aided research process can be divided into several stages: qualitative mathematical analysis of the initial problem, the development of algorithms and implementation of the problem in software, problem-oriented computational - periments, and physical interpretation of the results. The success of the study depends in many aspects on whether suf?ciently high standards of investigation can be maintained at all these stages and whether there is an intellectual core in these investigations that enables us to gain new scienti?c knowledge 1]. As an exampleofasuccessfulimplementationofsuchanapproachthathassettledalo- standing con?ict between theory and experiment, we can cite the development of thetheoryofresonantwavescatteringinthefrequencydomain. Theseresultshave been reported (see 2 16] and the bibliographies contained in those references), andtheyhaveservedasabasisforthedevelopmentofanumberofessentiallynew functional units and devices in millimeter and submillimeter radio engineering, vacuum electronics, and solid-state electronics, optics, and spectroscopy. The modern theory of transient electromagnetic ?elds is still lacking achie- ments that may be compared with those existing in the frequency domain, neither by the profoundness of the study, nor by the intensity of the study of electrom- netic phenomena and, as a result, by their applications. However, the process of accumulation of potentialities for a breakthrough is a process still going on."

Spis treści

Preface.- Numerical analysis of transient processes: fundamental results of the theory, methods and problems. Introduction. Main equations and fundamental results of the theory. Methods of solving initial boundary problems on the basis of space-time representations. Time domain methods.- Waveguides and periodic structures: exact ‘absorbing’ conditions on virtual boundaries in cross section of a regular wave guiding structures. Introduction. Compact waveguide units. 2-D scalar problems in cylindrical coordinates. Vector problems of the theory of open waveguide resonators. Problems of the electromagnetic theory of gratings.- Compact inhomogeneities in free space: virtual coordinate boundaries in scalar and vector problems of wave scattering theory. Introduction. Exact conditions for artificial boundaries in cylindrical (polar) coordinates. Exact conditions for artificial boundaries in Cartesian coordinates. Vector problems: spherical coordinates. Axially symmetric problems: spherical and cylindrical coordinates.- The simplest modifications of the ‘Exact ABCs’ approach and the associated numerical tests. Introduction. Radiators with infinite flanges. Wave radiation from a plane-parallel waveguide of arbitrary aperture. The problems of strong and remote field sources. Evolutionary basis of outgoing waves in the domains LQ with homogeneous and inhomogeneous filling. Numerical tests of the new exact conditions.- Transform operators in space of signal’s evolutionary basis: a time domain analogue of generalized scattering-matrix method. Introduction. Evolutionary signal basis and transform operators. Canonical problems of time domain. Algorithms for calculating transient characteristics of resonant inhomogeneities. Signals in the floquet channel: the transform operators and some canonical initial boundary-value problems.- Open periodic resonators and waveguides: novel results in electromagnetic theory of gratings. Introduction. Essential qualitative results inthe spectral theory of gratings. Dynamic patterns of spectral points in the frequency domain. Gratings in transient wave fields. Establishing of regularities. Pulse deformations by free propagation in regular section of the floquet channels.- Model synthesis of resonance quasi-optical devices: dispersive open resonators, absorbing coatings, pattern-forming structures. Introduction. Model synthesis of structures including grating dispersive elements (Frequency Domain). Inverse problems in electromagnetic theory of gratings (Frequency domain). Open dispersive resonators. Transient processes in the near zone of pulsed waves radiators.- References.- Appendix A.

Blurb

The principal goal of the book is to describe new accurate and robust algorithms for open resonant structures with substantially increased efficiency. These algorithms allow the extraction of complete information with estimated accuracy concerning the scattering of transient electromagnetic waves by complex objects. The determination and visualization of the electromagnetic fields, developed for realistic models, simplify and significantly speed up the solution to a wide class of fundamental and applied problems of electromagnetic field theory.

The book presents a systematic approach to the study of electromagnetic waves scattering which can be introduced in undergraduate/postgraduate education in theoretical and applied radiophysics and different advanced engineering courses on antenna and wave-guide technology. On a broader level, the book should be of interest to scientists in optics, computational physics and applied mathematics.