Study of eigenmode propagation and simulation of multiconductor microstrip transmission line crosstalk

The time response of coupled microstrip transmission line, obtained by modal analysis in frequency domain, has been studied. The authors have examined both voltage and current waves at each frequency component of the source by writing them explicitly in terms of eigenmodes. It is seen that, in general, all eigenmodes, whose numbers are equal to the number of signal conductors, are present in both voltage and current waves. Each eigenmode in turn contains forward and backward traveling components whose amplitudes are determined by terminal conditions. It is also pointed out that eigenmodes travel at slightly different velocities from each other. However, if the line is lossless the velocities for each eigenmodes are independent of frequency