Modal analysis of microstrip lines using singular value decomposition analysis of FDTD simulations

A comprehensive modal analysis of microstrip circuits using the singular value decomposition analysis of finite-difference time-domain simulation results has been performed. The detailed information have revealed new physical features, which are, to our best knowledge, seen for the first time. This realistic approach includes the 3-D configuration of structures and the full-wave electromagnetic properties. Increasing the aspect ratio of a continuous microstrip line strengthens the fundamental transverse electromagnetic mode and weakens the higher order transverse magnetic modes. However, the introduction of gap discontinuity in the line enhances the mode strength in the vicinity of the gap. The physical interpretations of these results have been discussed in the paper. Moreover, the effects of line topology on the evolution of modes are illustrated. This investigation has physical significance in the practical design of high-speed interconnects and system-onchip.