Simulation Guidelines for Wideband Ground Backed Coplanar Waveguide Transmission Lines

Abstract

This paper presents a series of guidelines to transition ground backed coplanar waveguide (GBCPWG) from the design phase to finite-element-method (FEM) electromagnetic simulations. A two step process is discussed including a design to circuit simulation and circuit to electromagnetic simulation. The majority of the paper focuses on the differences between circuit simulations and FEM simulations including port definition, side ground placement, and excitation of higher order modes. Careful consideration of these topics are crucial to achieve ideal performance over wide bandwidths, but also develop accurate simulation models. A DC-20 GHz CPWG transmission line is used as a design example throughout this paper.