Analysis of coplanar waveguide with conductor covered trapezoidal electrodes on a multilayered dielectric substrate

In this paper, we present an analysis of coplanar waveguide with conductor covered trapezoidal electrodes on a multilayered dielectric substrate. The method employed in our analysis uses a combination of the conformal mapping technique and the variational principle. With this method, a region including the trapezoidal electrodes and the grounded conductor cover is mapped into a welled structure through two times SC-transformation, and the energy in the multilayered dielectric region is expressed in an analytical form. Two separated regions are related by the boundary condition on the interface of two regions. Variational principle is applied to minimize the whole energy in the system and then find the discrete boundary nodal potential values. Numerical results for a CPW on a three-layered substrate used in a traveling-wave optical modulator are presented