Full wave analysis of microstrip discontinuities

In this paper, we present a full-wave analysis of microstrip discontinuities, including open-end, gap and dummy line. First, the Green´s function for dielectric slab is derived in a tensor form and the Sommerfeld integrals are carefully treated by pole extraction technique and folding approach. Then the integral equation formulated is solved by method of moments to obtain the current distribution along and transmission line and the S-parameters. With the scattering matrix given, the equivalent circuit parameters are also extracted. The phenomenon of resonance induced by dummy line is studied in the paper as well.