Analysis of TM and TE Modes in Eccentric Coaxial Lines Based on Bipolar Coordinate System

The cutoff wavenumbers, cutoff frequencies, field distributions and dispersive characteristics of TM and TE modes (higher order modes) in eccentric coaxial lines are carefully calculated by a new method directly based on the finite difference method (FDM) in bipolar coordinate system (BCS). Detailed comparisons with the previous results in the literature demonstrate the accuracy of the proposed method. Several characteristic features of the field distributions and the dispersion relations are also indicated. This method and its variations are very suitable and efficient for the computation of electromagnetic field problems in transmission lines with eccentric parallel cylinders.