Classification of metallic waveguides with complex cross-sections

A new classification scheme of waveguides with complex cross-sections is described. Only hollow metallic structures with a single contour are considered. Two new geometrical parameters, the number of ridges and the number of degrees of freedom, are proposed for evaluation of some of these waveguides. Transmission line characterisation criteria such as the type of propagating mode, and geometrical peculiarities and calculation methods are analysed.