Propagation along unbounded and bounded dielectric rods. Part 2: Propagation along a dielectric rod contained in a circular waveguide

The paper describes both approximate and exact methods for evaluating the phase-change coefficients of a circular waveguide containing an axial dielectric rod. Close correlation is found between the phase-change coefficients of this waveguide structure and those of an unbounded rod over a wide range of rod radii. The correlation enables an unambiguous classification of the modes of an unbounded rod to be made. Exact and perturbation expressions are derived for total transmitted power, power distribution and attenuation in the dielectric-rod-waveguide structure. Correlation with the attenuation coefficients of an unbounded rod is again predicted. The application of the results of the paper to ferrite devices is briefly mentioned.