Properties of cylindrical waveguides containing isotropic and anisotropic media

The cut-off conditions in circular waveguide containing an axial circular rod are considered when the rod is perfectly conducting and is surrounded by dielectric material, also when the rod and the surround are comprised of dielectric material, ferrimagnetic material or plasma. The characteristic equations involve certain cylindrical functions which depend on two variables. Contours of these functions are presented for cases corresponding to modes with zero and unit azimuthal dependence. Comparison is made between the cut-off conditions for the above media, and certain relationships between these conditions and the behaviour under propagating conditions are discussed. For modes possessing zero azimuth dependence, the characteristic equation can be solved under propagating conditions using the contour graphs. As an illustration of the method, results are presented for a cylindrical waveguide containing an unmagnetised plasma rod.