Electromagnetic Waves – serie

Written by two leading experts in the field, this exceptional book introduces the reader to the principles, theory and applications of physical layer wireless/mobile communications. In the area of wireless, the antennas, propagation and the radio channel used are inter-related; this book offers an explanation of that relationship, which is fundamental to the development of systems with high spectral efficiency.Channels, Propagation and Antennas for Mobile Communications emphasises the basic principles needed to establish an understanding of this technology. However, the tools required - such as the mathematics and statistics - are treated in the manner of a practical handbook, avoiding detailed derivations. The reader will develop a clear insight into the physics and effects of multipath and the use of multipath channels for communications. Propagation modelling, simulation and measurement, scattering, antenna principles, array antennas, adaptive antennas and smart antennas are also covered.This book will be a valuable reference for senior undergraduates and postgraduates in electrical engineering and communications. Practising design engineers, systems designers and engineering managers will also gain a sound understanding of the field.

The field of radio communications continues to change rapidly, and the second edition of this outstanding book, based on a popular IEE Vacation School, has been fully updated to reflect the latest developments. The introduction of new services and the proliferation of mobile communications have produced a growing need for wider bandwidths and the consequent need for frequency reuse. This book introduces the basic concepts and mechanisms of radiowave propogation engineering in both the troposphere and ionosphere, and includes greater emphasis on the needs of digital technologies and new kinds of radio systems. The content reflects the wide experience of an exceptional group of authors and the emphasis throughout is on modelling and prediction methods and the relevant ITU Radiocommunication Sector recommendations. Propagation of Radiowaves, 2nd Edition is essential reading for professionals involved in planning, designing and operating radio systems, as well as postgraduate students in the field.

Historically, electromagnetics and complex circuit modelling existed as separate disciplines, each with their own tools, models and even languages. More recently, however, the emergence of very high-speed digital circuits and pressure on the telecommunications market to move towards microwave and millimetre wave bands are increasing the need to find ways to combine the two fields.The consumer market demands low cost mass production devices operating at higher frequencies where the finite dimensions of the circuits with respect to wavelength can no longer be ignored. Similarly, integrated planar microwave circuits pose new modelling challenges, as neither conductors nor dielectrics can be considered as ideal at these frequencies and, consequently, most techniques and formulas developed over the past twenty years for dealing with ideal thin conductors no longer model the physical reality.These challenges are the main subject of this book which investigates analytical techniques encompassing the linear modelling of passive and active - in particular FET - structures. This timely book was primarily conceived as a bridge between the mathematical abilities of the pure EM theorist and those of the FET circuit modeller. However the resulting text will be of equal benefit to researchers in microwave and millimetric components and as a textbook for specialised courses.

This book is the first to present the application of parabolic equation methods in electromagnetic wave propagation. These powerful numerical techniques have become the dominant tool for assessing clear-air and terrain effects on radiowave propagation and are growing increasingly popular for solving scattering problems.The book gives the mathematical background to parabolic equation modelling and describes simple parabolic equation algorithms before progressing to more advanced topics such as domain truncation, the treatment of impedance boundaries and the implementation of very fast hybrid methods combining ray-tracing and parabolic equation techniques. The last three chapters are devoted to scattering problems, with application to propagation in urban environments and to radar cross section computation.This book will prove useful to scientists and engineers who require accurate assessment of diffraction and ducting on radio and radar systems. Its self-contained approach should also make it particularly suitable for graduate students and other researchers interested in radiowave propagation scattering.

The book discusses homogenisation principles and mixing rules for the determination of the macroscopic dielectric and magnetic properties of different types of media. The effects of structure and anisotropy are discussed in detail, as well as mixtures involving chiral and nonlinear materials. High frequency scattering phenomena and dispersive properties are also discussed.The book includes analysis of special phenomena that the mixing process can cause, such as the difference in character between a mixture and its constituent parts. Mixing results are applied to different materials in geophysics and biology. Reference is also made to the historical perspectives of dielectric modelling. Examples are included throughout the text.Aimed at students with research interests in electromagnetics or materials science, the book is also useful as a textbook in universities, as a handbook of mixing principles, and as a sourcebook for composite material design.

Microwave filters are vital components in a huge variety of electronic systems, including the rapidly growing communications industry behind mobile radio and satellite communications, as well as radar and other microwave technologies. Ian Hunter provides a graduate-level text that has the aim of enabling the engineer to understand the theory and design of microwave filters.This book is extremely thorough and covers fundamental circuit theory and electromagnetics, network synthesis, applications and the design of a variety of real microwave structures, all in a single source. The philosophy is to present design theories followed by specific examples with numerical simulations of the designs, accompanied by pictures of real devices wherever possible.The intended primary readership is professional engineers in the communications and microwave industries, where the book will be suitable for recent graduates working with and designing filters for the first time, through to engineering managers responsible for RF system design. MSc students in microwave and RF engineering will find the book highly relevant, as the author has developed much of the material from his graduate-level courses for university and industry. Theory and Design of Microwave Filters will also be a valuable reference work in the research community.

The ridge waveguide, which is a rectangular waveguide with one or more metal inserts (ridges), is an important transmission line in microwave engineering, through which many passive components can be achieved. As such it is a well-established and widely used element in commercial electronics and communications devices. This book collects together much of the work of Professor Helszajn, an international authoriy in the field, and will enable the reader to have direct access to this material without need for exhaustive search of research papers. Generously illustrated, it is likely to become the definitive reference source on this topic. The book includes closed-form and finite element calculations of the propagation constant, attenuation and mode spectrum for the ridge waveguide, as well as power-current and power-voltage definitions of impedance. Circular polarisation is also treated. Propagation properties where the waveguide has a dielectric filler are calculated. The treatment is then extended to more complex designs, including quadruple ridge waveguides with and without a gyromagnetic filler. The text includes descriptions of many of the passive devices which can be realised using these waveguides, including isolators, phase shifters and circulators. A treatment of the finline waveguide is included as its geometry is closely related to that of the ridge waveguide, leading to components such as the 3-port finline calculator.

Most antennas are assembled from conducting surfaces and wires. The usual approach to numerical analysis of such structures is to approximate them by small surface or wire elements, with simple current approximation over the elements (the so-called subdomain approach), which requires a large amount of computer storage. This book describes a novel general entire-domain method for the analysis of metallic antennas and scatterers which enables the solution of a very wide class of problems to be obtained using computers of relatively modest capability.Antenna-design engineers, scientists and graduate students interested in the analysis and design of electrically small and medium-sized metallic antennas and scatterers will find in this book a self-contained and extremely powerful tool that circumvents most difficulties encountered in other available methods.

This book is the first comprehensive treatment of microwave horns and feeds for reflector antennas for use in satellite and terrestrial communications, radar and radio astronomy. The feed for a reflector antenna is a crucial component because the performance of the reflector depends on a good feed to collect or radiate signals.The book presents the principles and applications of reflector and horn antennas with emphasis on the developments of the last decade. The background theory is included and the analytical techniques are explained. Extensive design data and numerous examples of practical horn and feed antennas are given.The book is a collaboration between four authors, bringing together an unrivalled knowledge of analytical techniques and experience in designing horns, feeds and reflector antennas. The book should be of value to both the research worker and the designer of practical feeds for reflector antennas.

Non-metallic materials and composites are now commonplace in modern vehicle construction, and the need to compute scattering and other electromagnetic phenomena in the presence of material structures has led to the development of new simulation techniques.This book describes a variety of methods for the approximate simulation of material surfaces, and provides the first comprehensive treatment of boundary conditions in electromagnetics. The genesis and properties of impedance, resistive sheet, conductive sheet, generalised (or higher order) and absorbing (or non-reflecting) boundary conditions are discussed. Applications to diffraction by numerous canonical geometries and impedance (coated) structures are presented, and accuracy and uniqueness issues are also addressed, high frequency techniques such as the physical and geometrical theories of diffraction are introduced, and more than i 30 figures illustrate the results, many of which have not appeared previously in the literature.Written by two of the authorities m the field, this graduate-level text should be of interest to all scientists and engineers concerned with the analytical and numerical solution of electromagnetic problems.

Open resonators, open waveguides and open diffraction gratings are used extensively in modern millimetre and submillimetre technology, spectroscopy and radio engineering. The physical principles of open electrodynamic structures are different from those of closed ones because of radiation loss, edges, multiconnected cross-sections and the need to take into account the behaviour of electromagnetic fields at infinity. The eigenoscillation and eigenwave spectra become complex, there are additional demands on the energy relations and the statements of spectral problems change.In this book the physical processes in open electrodynamic structures are analysed using a specially constructed spectral theory. The basic concept is that physical processes are observed at real frequencies, and continuation to the complex domain is considered as a mathematical method. The data obtained at complex frequencies give essential information about 'real' solutions at real frequencies. The approach developed allows not only the egular but a variety of anomalous dispersion laws and effects to be investigated.Written by two authorities in the field of mathematical modelling, the book should be of interest to all scientists and engineers concerned with modern methods of analytical solution of electromagnetic problems in open domains, as well as those studying theoretical electromagnetics.

Electromagnetic waves are guided by open structures in a variety of applications at radio, microwave, millimetric and optical frequencies. Examples range from the propogation of radiowaves down the shaft of an oil rig to that of light through an optical fibre. As the guide is open, radiation may also be present, for example from a microstrip-fed patch or a slot antenna. These twin aspects of waveguiding and radiation are in fact closely interwoven and this book is the first to deal with the two by means of a single mathematical formalism.The treatment develops from intermediate level guided wave electromagnetism through to frontier concepts and theoretical methods for discontinuities in open, hybrid mode 3D structures by way of real detailed problems taken from the fields of microwaves, millimetric waves and integrated optics. Examples include slotted waveguides, step discontinuities in slab waveguides, coupled and truncated ribguides, via holes in open microstrip, and air bridges in open coplanar waveguides. The unifying concept is the fundamental modal approach for both guiding and radiation, developed by the authors during the course of many years of research.The book is suitable for engineers and scientists dealing with the simulation of integrated planar antennas, millimetric circuits, integrated optics and other general open cylinder structures.

The cross-section method is an analytical tool used in the design of components required for low-loss, highly efficient transmission of electromagnetic waves in nonuniform waveguides. When the waveguide dimensions are large compared with the wavelength, a fully three-dimensional analysis employing modern numerical methods based on finite element, finite difference, finite integration or transmission line matrix formalisms is practically impossible and the cross-section method is the only feasible analysis technique.The method is not limited to oversized tubular metallic waveguides, but is employed intensively in areas such as fibre optic communications, antenna synthesis, natural waveguides (submarine, tropospheric and seismic), microwave radio links (Earth or space) and the design of absorbing surfaces and it may also be applied to many acoustic problems. The application of the method in special cases such as cut-off and resonant frequencies is covered, as well as the design of oversized waveguide components such as tapers, bends, polarisers and mode converters. Many useful formulas are given for the practical layout of such transmission line components. The use of computers in the application of the method and problems related to numerical analysis are also covered.

Over the last twenty years Corrugated horns have become widely used as feeds for microwave reflector antennas because of their high efficiency, good pattern symmetry and low cross-polarisation. They are increasingly used in antennas for satellite communications, radar, microwave point to point communications and radio astronomy.The authors draw on more than fifteen years experience to write the first book to appear devoted to the theory and design of corrugated horns and scalar feeds.The book explains why hybrid mode feeds are ideal feeds for reflectors. The propagation and radiation behaviour of cylindrical corrugated waveguides, narrow flare angle conical corrugated horns and wide flare angle corrugated horns are described. Factors relevant to the practical design of corrugated horns are discussed. Other topics treated include the measurement of corrugated horns.

Microwave Antenna Theory and Design is an unabridged reprint of the book published by McGraw Hill, as Volume 12 of the MIT Radiation Laboratory Series in 1949. The Editor of the Volume, the late Professor Samuel Silver, contributed extensively to the text and subsequently became one of the best known people in the world of radio science.Although published in 1949, Microwave Antenna Theory and Design, or 'Silver' as it is commonly known, still remains today essential reading for all those engaged in the microwave antenna field and many subsequent texts have assumed the readers' familiarity with the material in Silver. Access to it has become increasingly difficult with the passage of time and so it is hoped that this reprint will find a ready market among engineers.

The Waveguide Handbook is an unabridged reprint of the book first published in 1951 by McGraw Hill as Volume 10 of the MIT Radiation Laboratory Series.Although the primary aim of the book is to present the equivalent-circuit parameters for a large number of microwave structures, a brief but coherent account of the fundamental concepts necessary for their proper utilisation is included. The first three chapters summarise both the field and network theoretic considerations necessary for the derivation and utilisation of the basic transmission line-equivalent-circuit formalism. The mode concept and transmission-line formulation of the field equations are introduced in Chapter 1. This chapter contains an engineering treatment of the transmission-line theory necessary for the description of propagating and nonpropagating modes in the more important types of uniform and nonuniform waveguides. The field-structure, propagation, attenuation, etc., characteristics of the transmission-line modes so described are compiled in Chapter 2, with both quantitive and pictorial detail. The elements of microwave-network theory required for the analysis, representation, and measurement of the equivalent circuits for N-terminal microwave structures are outlined in Chapter 3; also contained in this chapter is a sketch of some of the field theoretic methods employed in the derivation of the equivalent-circuit parameters reported in Chapters 4 to 8. Although most of the above material is written for the impedance-minded microwave engineer, some of the sections should be of interest to the applied mathematician. The remaining chapters contain a compilation of the equivalent-circuit parameters for a variety of nondissipative N-terminal microwave structures. In Chapter 4 a number of two-terminal structures, such as beyondcutoff and radiative waveguide terminations, are treated. Obstacle and aperture discontinuities in waveguides, gratings in free space, etc., are among the four-terminal structures described in Chapter 5. Chapter 6 deals with six-terminal microwave structures and contains the equivalent-circuit parameters for a number of E-and H -plane T- and Y-junctions, bifurcations, etc. Several eight-terminal structures are treated in Chapter 7. Chapter 8 contains the circuit description of a number of typical composite microwave structures; dielectric-filled guides, thick apertures, etc.This edition also contains a new preface by the editor and several pages of errata which he has collected over the past thirty-five years.

The continuous development of the Geometrical Theory of Diffraction (GTD), from its conception in the 1950s, has now established it as a leading analytical technique in the prediction of high-frequency electromagnetic radiation and scattering phenomena. Consequently, there is an increasing demand for research workers and students in electromagnetic waves to be familiar with this technique. In this book they will find a thorough and clear exposition of the GTD formulation for vector fields. It begins by describing the foundations of the theory in canonical problems and then proceeds to develop the method to treat a variety of circumstances. Where applicable, the relationship between GTD and other high-frequency methods, such as aperture field and the physical optics approximation, is stressed throughout the text. The purpose of the book, apart from expounding the GTD method, is to present useful formulations that can be readily applied to solve practical engineering problems. To this end, the final chapter supplies some fully worked examples to demonstrate the practical application of the GTD techniques developed in the earlier chapters.

Between 1950 and 1965, there was a spate of intense activity to investigate the theory and application of ferrite materials at microwave frequencies, and in the early 1960s a number of textbooks on the microwave applications of ferrites were published, but nothing comprehensive since. Now this book has been written to consolidate all the investigations of ferrites for microwave applications, to look back at earlier publications from the viewpoint of a mature technology, and to bring the story up to date. This book attempts to give all the structures and applications using ferrites at microwave frequencies that havebeen investigated or contemplated, using the engineer's rather than the physicist's approach. It starts with a full mathematical treatment of the interaction of an electromagnetic wave with a gyromagnetic ferrite material for simple boundary conditions. These results are then extended to give a field descriptive approach to describe the mode of operation of all the different microwave devices.

In the past few years, the concept of creating microwave antennas using microstrip has attracted increasing attention and viable practical designs are now emerging. The purpose of this monograph is to present the reader with an appreciation of the underlying physical action, up-to-date theoretical treatments, useful antenna design approaches and the overall state-of-the-art situation. The emphasis is on antenna engineering design, but to achieve this goal it has been necessary to delve into the behaviour of microstrip in a much wider sense and also include aspects of electromagnetic analysis. As a consequence, the monograph will also be of interest to microstrip circuit designers and to some extent those seeking electromagnetic problems of a challenging nature.The astronomical progress in miniaturising and integrating electronic circuits in the past decade has recently crerated a positive demand for a new generation of antenna systems. In principle, microstrip antennas are thin planar configurations that are leightweight, low cost, easy to manufacture and can be made conformal with the surfaces of vehicles, missiles etc. The compatibility of microstrip antennas with integrated electronics is another great advantage. However, the microstrip wavetrapping effects inhibit the radiation mechanism and must be taken into account in antenna design. Wave-trapping effects in substrates involve the study of surface waves and discontinuities in open waveguide structures. The microstrip antenna designer must therefore encompass many more effects than previously considered by microstrip circuit designers. It is for these reasons that the scope of this monograph is necessarily somewhat wider than the title may suggest.The ten chapters are a blend of introductory, practical and theoretical treatments and likely future developments are also highlighted. A good selection of past and current references are given and each chapter concludes with a helpful summary comment.

This book treats the phenomena associated with the propagation of short radio waves between terminal points, whether they be the radar antenna serving a dual purpose or the antennas of a communications system. The intention is to present a summary of the state of knowledge in the microwave propagation field at the close of the war. There has been no attempt to produce either a handbook or textbook, but only an interim report on a rapidly changing subject. An attempt has been made to survey all relevant information that was available, from whatever source, and to summarise as much of it as was feasible.

Principles of Microwave Circuits is an unabridged reprint of the book first published in 1948 by McGraw Hill as Volume 8 of the MIT Radiation Laboratory Series. Since the original publication of this book, a number of errors have been brought to our attention. Corrections of these errors are incorporated in this edition.In the engineering application of low-frequency currents, an important step forward was the development of the impedance concept and its utilization through the theory of linear networks. It was almost inevitable that this concept would be generalized and become useful in the application of microwaves. This volume is devoted to an exposition of the impedance concept and to the equivalent circuits of microwave devices. It is the intention to emphasise the underlying principles of these equivalent circuits and the results that may be obtained by their use. Specific devices are not discussed except as illustrations of the general methods under consideration. The results of such calculations that had been performed up to that time are compiled in Vol. 21 of the Electromagnetic Waves Series, the Waveguide Handbook edited by N. Marcuvitz, and these results are used freely. Although the work of the Radiation Laboratory at MIT was the development of military radar equipment, the principles discussed in this volume can be applied to microwave equipment of all kinds.

The subject of antenna measurements is one which has undergone revolutionary changes in recent years, in particular within space applications, where high demands are placed upon antenna design and construction.This book represents the specific measurement technique known as the spherical near-field method. The theoretical treatment of the method is detailed but of sufficient generality to make the book useful as a basis for further research on near-field measurements and antenna coupling problems. Practical aspects of antenna test ranges, data processing schemes and measurement procedures are described. Other topics covered are measurement error analysis and generation of plane wave fields.The authors draw on the experience from the development, sponsored by the European Space Agency, of one of the first spherical near-field test ranges. They have contributed to the establishment of spherical near-field testing as a highly accurate and versatile method, currently under implementation at test ranges worldwide.

Ionospheric Radio replaces an earlier publication Ionospheric Propogation and is aimed at professional scientists, engineers, and students who need an intermediate-level reference and/or text. Students of aeronomy and radio wave propogation are introduced to basic wave theory in absorbing, anisotropic and dispersive media, and to the physics of production, loss and movement of plasma in the ionosphere in the presence of the geomagnetic field. Various radio techniques are described, and applications to the interpretation of ionospheric structures and dynamics are presented. The application of ionospheric data to radio communications problems includes the use of numerical and physical models and prediction techniques, and methods for calculating signal strengths are presented. Topics include Earth-space propagation, ionospheric modification, ionospheric disturbances, propagation by scattering from plasma irregularities, topside sounding, and propagation on frequencies from the extremely low to the super high. Reference lists are extensive and a section of questions tests the reader's understanding of the material.

There are several ways to classify electromagnetic waveguides. Depending on their boundaries, they can be classified into waveguides with perfectly reflecting walls or finite impedance walls, as well as open waveguides. In terms of their applications, there are the low attenuation and low delay distortion waveguides for telecommunication, the low crosspolar field waveguides used as feeds for reflector antennas in frequency reuse schemes, as well as the leaky feeders in continuous access communication systems. There are also the natural waveguides such as tunnels and the earth-ionosphere waveguide.This text is an attempt to give a unified, analytical treatment to most of these diverse types of waveguides. Emphasis is given to modal characteristics, modal excitation and mode scattering at longitudinal discontinuities. The book will serve not only as a text for undergraduate courses, but also as a reference book for those involved in research work on electromagnetic waveguides.

This is an enlarged and revised second edition of a book first published in 1978 and reprinted twice since then. The new edition includes updates to all the original chapters, plus two new chapters on developments in superresolution techniques and their application to direction-finding arrays.Modern direction finders, capable of measuring elevation angles as well as azimuth angles on the components of multi-ray wavefields, have become powerful tools for research in ionospheric physics and HF radio propagation. The complexity of the problem of resolving closely-spaced rays requires the combined use of wide aperture antenna arrays, multichannel receiving systems and sophisticated digital processing techniques.Published research papers over the last 12 years provide a rich source of information on the development of superresolution algorithms for use in radar, sonar, geophysics and spectral analysis, as well as radio direction finding. Dr Gething reviews the important methods and results, showing how some of the new techniques are related to the wavefront analysis methods described in the first edition. The text is illustrated with computer plots of model wavefields and contain important results on the loci of constant phase and amplitude, and on the statistical properties of bearing-error distributions for specified models. The collection and interpretation of ionospheric data for the purpose of mode identification, and the statistical theory of DF plotting algorithms, are also discussed.Wavefront analysis and superresolution may be regarded as extensions to classical array theory. The basic principles are widely applicable and should therefore be of interest to research workers in radar, sonar, radioastronomy and adaptive array theory, as well as HF radio direction finding.

Electrodynamic Theory of Superconductors is the first book of its kind. It gives a unified and comprehensive theoretical treatment of electromagnetic, thermal and mechanical phenomena in superconductors. Basic concepts and principles in continuum electrodynamics are introduced, with particular emphasis on methodology. Electrodynamic models are developed to study magnetoelastic and thermoelastic superconductors. The author also introduces phenomenological London theory, Cinzburg-Landau theory, electrodynamic models for superconducting thin films, AC losses and Josephson junctions, and BCS microscopic theory of superconductivity. This book can be used as a post graduate level text and as a reference book for researchers and engineers working in the field of applied superconductivity and related areas.

This book describes VHF and UHF antennas for the range 30-3000 MHz developed over the last 50 years. Many designs that have not previously been described in detail are covered. The author's long, practical experience is shown in numerous examples of new uses for old designs.Particular attention is paid to the effects on the antennas of the local environment and the structures on which they are mounted, both fixed and mobile, including man. Methods of predicting and measuring the performance of antennas are described at length. The effect of adverse environments on antennas are discussed, and suggestions are given for measruing electrical performance under these conditions.The book is primarily aimed at practising antenna engineers - the theory of basic antennas is kept to a minimum but given where appropriate for the less well-known types.

This book describes new, highly effective, rigorous analysis methods for electromagnetic wave problems. Examples of their application to the mathematical modelling of micros trip lines, corrugated flexible waveguides, horn antennas, complex-shaped cavity resonators and periodic structures are considered.Special attention is paid to energy dissipation effects. Various physical models and methods of analysis of dissipation are described and approximate formulas and computer-based calculation results for dissipation characteristics are given and compared with experimental data. Ways of decreasing dissipation in waveguides and resonators are discussed.The book will be of interest to physicists and engineers working on the theory and design of microwave and millimetre-wave components and devices. Designers in microwave engineering will find here all the information they need for choosing the correct waveguide (resonator) for a stipulated dissipation characteristic. The numerical algorithms and formulas can be directly applied to CAD systems. The book is also relevant for students of electromagnetism and microwave circuits.

There have been significant developments in the field of numerical methods for diffraction problems in recent years, and as a result, it is now possible to perform computations with more than ten million unknowns. However, the importance of asymptotic methods should not be overlooked. Not only do they provide considerable physical insight into diffraction mechanisms, and can therefore aid the design of electromagnetic devices such as radar targets and antennas, some objects are still too large in terms of wavelengths to fall in the realm of numerical methods. Furthermore, very low Radar Cross Section objects are often difficult to compute using multiple methods. Finally, objects that are very large in terms of wavelength, but with complicated details, are still a challenge both for asymptotic and numerical methods. The best, but now widely explored, solution for these problems is to combine various methods in so called hybrid methods.Asymptotic and Hybrid Methods in Electromagnetics is based on a short course, and presents recent developments in the field.