3-D low-loss coplanar waveguide transmission line structures with wide range of characteristic impedance for MMICs

Newly developed transmission line structures using the great flexibility of three-dimensional multilayer technology have been designed and fabricated. In this paper we demonstrate that monolithic microwave integrated circuits (MMIC) coplanar waveguide (CPW) transmission lines with a wide range of characteristic impedance can easily be designed using the multilayer technique. Furthermore this implementation can avoid the well known current crowding effects on the conductor edges. Consequently dissipation loss can be reduced. The system of three layers of metals and two layers of sandwich polyimide as dielectrics was employed. The transmission lines have been characterised and show good performances.