G. F. Zargano, V. V. Zemlyakov, A. V. Hohlachev

Transverse junctions are widely used in waveguide technologies for selective devices design. The selective devices design based on waveguides of complex cross-section, especially in multimode operation, is of great practical interest and could be a perspective investigation because such waveguides, for example ridge-, double ridge-, cross-guides, offers much advantages, specifically better range and mass performances, low losses in comparison with traditional waveguides (circular and rectangular). In this paper the calculation and analysis of parameters of single and combined transverse junctions in H-waveguide in multimode case is described. Electromagnetic fields and cutoff wave numbers of propagating and non propagating TE and TM waves are calculated by method of partial regions including field singularities at the edge. The dependences of real and imagine parts of admittance of single transverse junctions for dominant and higher modes are presented. The calculation results of S-parameters of thick diaphragm in double ridge waveguide (two transverse junction concatenation) are shown. In calculation of multimode scattering matrix the interaction of irregularities by higher order non propagating modes is included. The comparison of calculation results with the results of computer simulation by numerical techniques confirms the efficiency of developed algorithms.