Modes in a Rectangular Wave-Guide Filled with an Anisotropic Dielectric

摘要

The normal modes in a rectangular wave-guide filled with an anisotropic dielectric are examined. It is known that the general wave equation in rectangular coordinates is a quartic equation in k, the propagation constant. When the guide axis coincides with the principal axis of the dielectric, the wave equation becomes quadratic in k to the second power. This makes possible the existence of cutoff modes of a more complicated type involving a complex k sub z instead of the usual type where k sub z is real. These modes have unusual orthogonality properties. The existence of these modes leads to the investigation of propagating modes with asymmetric transverse distribution or with a phase-front not normal to the guide axis. (Author)