Theory of Coaxial Wave Guides with Dielectric and Magnetic Discontinuities

Abstract

Analytical solutions are derived for the electromagnetic E, Hand T waves in coaxial wave guides of inner radius a and outer radius b and of infinite length, which are filled in the direction of propagation z with media of different electric permittivity 8 and magnetic permeabilityjz such that: 8 = 8b Il = III for - CIJ ~ Z < - d; 8 = 82, Il = 112 for - d < z < +d; 8 = 83, Il = 113 for +d < z ~ + CIJ. The power reflection and transmission coefficients of the E, Hand T waves are given as a function of frequency Q) and the guide parameters 81, Ill, a, band d. It is shown that the reflection and transmission coefficients exhibit a periodic fine structure in the frequency space above the 'cutoff frequency as a result of the spatial eigenvalue nature of the field solutions. The theory presented provides analytical foundations for the measurement of the frequency-dependent electric permittivity and magnetic permeability of samples in coaxial wave guides.