Accurate modelling of unilateral finline-coplanar waveguide transition

Using the spectral domain technique in conjunction with finite element slot field expansions, the scattering characteristics of the unilateral finline-coplanar waveguide transition are analysed. Flexible rooftop functions varying in both the transverse and longitudinal directions are used instead of a uniform rooftop function as expansion functions to handle arbitrary slot width structures. A typical example is computed. The numerical results for the special case agree well with those available in the literature.