Full-wave analysis of conductor losses on MMIC transmission lines

A mode-matching analysis of lossy planar transmission lines is presented. The metallic layers are treated in the same way as the remaining waveguide subregions, with each of them characterized by its complex dielectric constant. This leads to a fully self-consistent description of the conductor losses that offers two principal advantages compared to the usual perturbation methods: the approach remains valid for metallization dimensions on the order of or even smaller than the skin depth, and non-TEM (transverse electromagnetic) waveguide modes can be analyzed. The validity and usefulness of the extended mode-matching method are demonstrated through a comparison with previous theoretical and experimental work on GaAs MMIC (monolithic microwave integrated circuit) transmission lines. First results on microstrip and slot lines are given.<>