Quasi-static model for circular transmission lines

Models have been developed for circular transitions of commonly used transmission lines, such as the stripline and the microstrip line, and have been included in commercial microwave CAD packages. Yet no general theory has been made for modeling the bends of other transmission lines, such as the coplanar waveguide. A model was derived for general circular transmission lines, based on a quasi-static approximation. This model was applied to a circular coplanar waveguide. Measurement of the latter showed good agreement with the model.