Modeling of some coplanar waveguide discontinuities

Abstract

Lumped equivalent circuit models for several coplanar waveguide (CPW) discontinuities such as an open circuit, a series gap in the center conductor, and a symmetric step in the center conductor are presented, and their element value are given as a function of the physical dimensions of the discontinuity. The model element values are de-embedded from measured S-parameters, and the effects of the center conductor width and the substrate thickness on the equivalent circuit element values are obtained. The characteristics of a CPW right-angle bend using a compensation technique are presented. The frequency dependence of the effective dielectric constant is measured and compared to computed values.