Interline coupling of ultra-high-speed pulse propagating on PCB

Interline coupling of rectangular ultra-high-speed pulses of varying pulsewidth, propagating on printed-circuit board, is investigated parametrically using a formulation based on the difference in the odd-mode and even-mode propagation speeds. Results show that the coupling effects do not decrease monotonically with increasing line spacing. In particular, there is a nonlinear relationship with respect to line spacing and linewidth such that the two-to-one ratio rule of thumb may actually result in higher coupled energy than smaller line spacing would