A circuit board design is disclosed that is useful in high-speed differential signal applications uses either a via arrangement or a circuit trace exit structure. A pair of differential signal vias in a circuit board are surrounded by an opening that is formed within a ground plane disposed on another...http://www.google.se/patents/US20050202722?utm_source=gb-gplus-sharePatent US20050202722 - Preferential via exit structures with triad configuration for printed circuit boards
