Characterization of corrugated waveguides by modal analysis

A general formulation for the characterization of corrugated waveguides is presented. The formulation is based on modal expansion in the different smooth-walled waveguides which constitute the corrugated structure and on the use of mode matching at discontinuities. The use of an admittance matrix formulation and a suitable root-finding algorithm leads to a rigorous and efficient technique. Dispersion curves are presented for corrugated waveguides of circular and rectangular cross-sections. Complex modes are obtained for deep corrugations. The effect of the finite thickness and width of teeth and slots on the dispersion behavior is shown