Solution of Fin-Line Discontinuities through the Identification of its First Four Higher Order Modes

The dominant and the first four higher order modes in a unilateral fin-line are accurately described from a thorough Spectral Domain Approach. Then, coupling coefficients between eigenmodes at a discontinuity that have to be introduced into the scattering matrix formulation, are directly computed in the Spectral Domain. Finally, fin-line discontinuities often used for impedance transformation are investigated and comparison with measurements in K/sub a/ band are given .