Zx. Shen et Rh. Macphie, AN IMPROVED MODAL EXPANSION METHOD FOR 2 CASCADED JUNCTIONS AND ITS APPLICATION TO WAVE-GUIDE FILTERS, IEEE transactions on microwave theory and techniques, 43(12), 1995, pp. 2719-2722
An improved modal expansion method is described for the scattering mat
rix of a cascaded network which consists of an enlargement junction co
mbined with a reduction junction. The new method can significantly red
uce computation time and requirement of computer memory. Application t
o iris coupled waveguide cavity filters is demonstrated. Numerical res
ults for a rectangular waveguide cavity filter are given.