Methods to reduce radiation from split ground planes in RF and mixed signal packaging structures

Split ground planes are sometimes used in RF and mixed signal packages in order to isolate the RF and analog circuits from the digital circuits. Undesired radiation in a packaging environment may occur when a signal trace is routed over a slot in the ground plane. This paper examines and investigates ways to eliminate signal coupling into split ground plane structures and assesses the impact of this reduced coupling on signal integrity in a packaging environment. Suggested methods to reduce coupling of energy into the slot are to alter the shape of the slot with RF chokes or corrugations.