AN ANALYTICAL METHOD FOR DIRECT CALCULATION OF E AND H-FIELD PATTERNSOF CONDUCTOR-BACKED COPLANAR WAVE-GUIDES

A new direct method of computing the electromagnetic field patterns su rrounding the conductor-backed coplanar waveguide (CPW) structure is p roposed. Analytical closed-form expressions describing the quasi-TEM f ield pattern in both the air and the dielectric substrate for conducto r-backed CPW's are presented. This approach is based on a new techniqu e which employs a series of inverse conformal mappings to transform a known field pattern from a rectangular structure back into the CPW str ucture in Order to obtain its unknown field pattern directly. A comput er program based on this method has demonstrated the speed at which th e fields can be plotted compared to existing methods which require rep etitive application. Graphical results of these field patterns are pre sented as a function of the CPW's geometry and dielectric substrate th ickness. These field maps which have been directly drawn with true cur vilinear squares enable the determination of power flow density, since the same power Bows through each square. This direct method of charac terizing the power Bow density throughout the CPW structure could beco me an important design tool for the modeling of coplanar monolithic mi crowave integrated circuits (CMMIC's).