Topics in Guided- Wave Pro2:>agation 

 Through Gyromaguetic Media 



Part I — The Completely Filled Cylindrical Guide 



By H. SUHL and L. R. WALKER 



(IManuscrijit received January 26, 1954) 



The characteristic equation for the propagation constants of waves in a 

 filled circular guide of arbitrary radius is written in terms of magnetizing 

 fi£ld and a carrier density, which are shown essentially to determine the 

 dielectric and permeability tensors for a gas discharge plasma and for a 

 ferrite. The complex structure of the spectrum of propagation constants and 

 its dependence upon radius and the two parameters are analyzed by a semi- 

 graphical method, supplemented by exact for midae in special regions. Thus 

 the course of individual modes may be charted with fair accuracy. 



1. INTRODUCTION 



Any material medium which propagates electromagnetic disturbances 

 possesses a local electric or magnetic structure and it is just the motion of 

 the electric or magnetic carriers under the fields of the disturbance that 

 determines how the propagation takes place. If a dc magnetic field be 

 applied to the medium one may expect the local response to be altered 

 and, consequently, to find changes in the character of the propagation. 

 Gyromagnetic media are those for which such changes are sufficiently 

 large to be experimentally significant. For plane waves and for optical 

 frequencies the experimental effects and their explanation have been 

 familiar for a great many years. The non-reciprocal rotation of the plane 

 of polarization of light travelling parallel or antiparallel to an applied dc 

 magnetic field, Avhich is known as the Faraday effect, is such a phenom- 

 enon. So also is the fact that the medium becomes doubly refracting for 

 arbitrary directions of propagation. 



Interest in gyromagnetic media at longer wavelengths first arose in 

 connection with radio propagation in the ionosphere. The ionosphere is 

 essentially an ionic cloud and the earth supplies a magnetic field, which, 

 for the charge densities involved, is sufficient to produce a large effect 



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