Signal propagation and radiation of single and differential microstrip traces over split image planes

This paper deals with the effect of split power or ground planes on single and differential signals propagating on microstrip structures using the FDTD method. The effect of the split in the image plane on the propagated signals as well as on the radiated fields is examined for different trace separations. The improvement of signal quality and the reduction of the unwanted radiation obtained by running tightly coupled differential traces over the split is examined. The excitation of slot line modes in the split is shown.