Dispersion Characteristics of the Dominant Mode on a Completely Shielded Conductor-Backed Slotline

This paper presents an analysis of a completely shielded conductor-backed slotline using the spectral domain technique. Attention is paid to dominant and higher order modes with even symmetry of the transversal electric field component in the slot parallel to the dielectric interface. The dependence of the phase constant and the characteristic impedance of the line on cross-sectional size, permittivities and frequency are given. It has turned out that the line is suitable for circuit design when the dominant requirement is for low characteristic impedance. Numerical examples highlight particular aspects of the mode propagation over the line. The consequence of setting ε0 in the whole cross-section of the line is a waveguide containing a partition in the H plane with a longitudinal slot. An analysis of this guide by the spectral domain method is presented and typical frequency dependent phase constant and characteristic impedance patterns are shown