From the preface: Textbooks and monographs on microwave theory contain very little material on methods of calculating microwave absorption. However, problems do exist in this field; this is confirmed by the vast amount of journal publications on the issue, especially during the last decade. There are some mutually contradictory views concerning a number of aspects, and arguments about resolved questions regularly arise. This is largely due to the absence of a monograph dealing with the problems of electromagnetic wave absorption in waveguides, resonators and periodic structures. This book attempts to fill the gap.
The introduction reviews possible ways of reducing losses in waveguides and resonators, it formulates boundary-value problems of electromagnetics for cases when losses are considered, and gives analytical and numerical methods of analysis. Chapter 2 deals with the formulation of impedance boundary conditions for a high skin effect in various conducting media.
Chapter 3 presents the theory of regular waveguides with finitely conducting walls, and Chapter 4 the theory of cavities when the surfaces and the medium inside are absorbing. These chapters present the derivation of general formulae for the attenuation coefficient and \(Q\)-factor and consider concrete practical applications. The principal errors associated with the solution of these problems are also discussed.
Chapters 5 and 6 deal with wave diffraction by imperfectly conducting gratings in both free space and inhomogeneous anisotropic media. The main emphasis is on the description of dissipative resonance effects, in particular the effect of the abnormally low dissipation.
Chapter 7 considers the attenuation of eigenmodes in periodic waveguides. It presents results obtained for low-loss flexible corrugated waveguides and high-quality corrugated resonators of the millimetre waveband etc. A number of theoretical results confirmed by experiment are included.
The book is intended for physicists and engineers performing theoretical research and designing microwave and millimetre-wave devices, and for students and postgraduates involved in these issues. It can be used by a design engineer to select a suitable type of waveguide (resonator) and methods of computing its parameters.