Microwave Ferrites And Ferrimagnetics

Includes a full mathematical treatment of the interaction of an electromagnetic wave with a gyromagnetic ferrite material.

During the last three decades, interest in the field of interaction of microwaves with ferrimagnetics has steadily increased. Investigations in tlris field have led to the development of a number of devices used for a variety of applications. The initial emphasis of the investigators was on the microwave behavior of ferrimagnetics placed in cavities and metallic waveguides and associated devices. This work has been presented in various books, monographs, and reviews written during the sixties. In recent years, interest in microwave propagation in ferrimagnetics has shifted from loaded waveguides to relatively new areas, e. g. , magnetostatic and magnetoelastic waves in layered structures, microwave propagation in ferrimagnetic strip lines and microstrips, etc. Such investigations are important from the viewpoint of devices such as delay lines, filters, convolvers, guided wave amplifiers, striplines, and microstrip phase shif ters, circulators, edge guided mode isolators, etc. As such, we feit the need for a text (meant for graduate students starting work in these areas as weil as practicing electrical engineers and applied physicists) which presents a coherent account of the various aspects of propagation of microwaves (electromagnetic as weil as magnetoelastic) in biased ferrimagnetics and discusses the relatively recent developments in the theory and operation of the aforementioned devices, and this book is the result. A biased ferrimagnetic is, in the mathematical sense, a complicated medium, electromagnetically as weil as elastically.

Annotation This text serves as a transition between introductory courses in electromagnetism and rapid advances in microwave technology. Discussions on areas such as lossy and multiple connect are designed to arouse the interest of novice students, enhance analytical skills of practitioners, and invite advanced students to explore novel concepts developed here. Discussions on ferrite networks are presented as an integral part of the author's theoretical methodology. Includes exercises and answers. For use in an undergraduate elective course. Annotation copyrighted by Book News, Inc., Portland, OR.

The Use of Ferrites at Microwave Frequencies describes the applications of ferrites at microwave frequencies and the apparatus involved. Topics covered range from the properties of ferrites to gyromagnetic and non-reciprocal effects, ferrite isolators, circulators, and modulators. The use of ferrites in variable frequency filter cavities is also discussed. Mathematical explanations are reduced to the strict minimum and only the results of calculations are indicated. This book consists of seven chapters and opens with a review of the theory of magnetism, touching on subjects such as the BOHR magneton, diamagnetism and paramagnetism, ferromagnetism and antiferromagnetism, ferrimagnetism, and demagnetizing. The next chapter deals with the elementary theory of gyromagnetic effects and covers the kinetic moment theorem, precession of the spin moment, gyromagnetic resonance, complex permeability, and gyromagnetic effects in the atom. The reader is then introduced to ferrites and their properties; non-reciprocal effects and their applications; and ferrite isolators, circulators, and modulators. The final chapter describes the use of ferrites in the design of cavities whose resonant frequency is controlled by a magnetic field or filters with variable characteristics. This monograph is written primarily for microwave and electronics engineers.