Scattering parameters of a step discontinuity in a suspended microstrip line

The dominant and first nine higher-order modes in a suspended micro-strip lines are accurately described from a thorough spectral-domain approach. Then coupling coefficients between eigenmodes at a step width discontinuity to be used in the generalized scattering matrix formulation are directly computed in the spectral domain. Scattering parameters of the dominant mode in the Ka band are presented.