Signal integrity issues at split ground and power planes

The signal integrity issues at split ground and power planes are studied by 3D, time-domain, full-wave simulations and SPICE circuit simulations. Dynamics of the mode conversion between microstrip line mode and slotline mode is presented as a series of snapshots of a computer animation. Equivalent circuits based on transmission line model and mode conversion are developed and validated by published experimental data. It is also demonstrated that under certain resonance conditions, the unwanted noise coupling between two signal lines that cross the same ground slot can reach a very high percentage. Design rules for choosing the slot width for isolated ground and power islands in mixed-signal environment are also discussed.