Backplane footprint for high speed, high density electrical connectors

A printed circuit board comprising:

• a plurality of layers including attachment layers and routing layers;
• and
• columns of via patterns formed in the plurality of layers, wherein via patterns in adjacent columns are offset in a direction of the columns, each of the via patterns comprising:
• first and second signal vias forming a differential signal pair, the first and second signal vias extending through the attachment layers to at least one breakout layer of the routing layers;
• at least one antipad surrounding the first and second signal vias;
• and
• first and second conductive shadow vias located between the first and second signal vias of the differential pair on a first line that is perpendicular to a second line through the first and second signal vias and that is midway between the first and second signal vias.