Electromagnetic Performance and Application of Microwave Ferromagnetic Devices

This paper is dedicated to the consideration of modern designs and fields of application of nonreciprocal isolators and circulators based on ferromagnetic materials. We provide basic electromagnetic insight into working mechanisms of ferrite-based microwave passive devices. Structural peculiarities of the isolators applying the ferromagnetic resonance effect were revealed. Locations of dielectric and ferromagnetic plates were obtained from the analysis of theoretical fields distributions of the fundamental TE$_{\mathbf{10}}$ mode of the rectangular waveguide. The dependences of magnetic field polarization on the transversal coordinated of the waveguide are illustrated in the paper. Secondly, we have presented the structure of a ferromagnetic isolator based on the field displacement effect. Features of its structure and operation principle are considered. The circuit for possible application of the isolators in perfect excitation sources is presented. In addition, a typical designs of Y-shaped circulators based on ferromagnetic loading are considered and analyzed in the paper. Fields of application of Y- and X-shaped circulators in modern radio engineering systems are presented. Possible circuits for simultaneous multichannel transmission and isolation based on circulators are developed.