A substrate comprising: a body defining: a leading end and a trailing end opposite the leading end along a longitudinal direction, the leading end configured to be inserted into a receptacle of a complementary electrical connector in a mating direction that is oriented along the longitudinal direction, first and second sides spaced from each other along a lateral direction that is substantially perpendicular to the longitudinal direction, and first and second outer surfaces that are spaced from each other along a transverse direction that is substantially perpendicular to each of the longitudinal direction and the lateral direction; a plurality of electrical signal traces at the first surface and defining a mating end, the electrical signal traces arranged in pairs of immediately adjacent signal traces along the lateral direction a plurality of electrical ground traces at the first surface and defining mating ends and termination ends opposite the mating ends along the longitudinal direction, the electrical ground traces defining pairs of immediately adjacent ground traces along the lateral direction, wherein respective pairs of ground traces are disposed between pairs of immediately adjacent signal traces; a plurality of electrically conductive bridges that are electrically and mechanically connected to first and second ground traces of respective pairs of immediately adjacent ground traces that are disposed between immediately adjacent pairs of signal traces, thereby commoning the first and second ground traces of each of the respective pairs of immediately adjacent ground traces in a plane that is defined by the longitudinal direction and the lateral direction, wherein the electrically conductive bridges are disposed at the first outer surface, the electrically conductive bridges are isolated from all signal traces, and the electrically conductive bridges do not contact each other; an electrically conductive ground plate disposed between the first surface and the second surface, wherein the electrically conductive ground plate is aligned with the mating ends of the ground traces along the transverse direction; and electrically conductive vias that extend from respective ones of the bridges to the electrically conductive ground plate. a body defining: a leading end and a trailing end opposite the leading end along a longitudinal direction, the leading end configured to be inserted into a receptacle of a complementary electrical connector in a mating direction that is oriented along the longitudinal direction, first and second sides spaced from each other along a lateral direction that is substantially perpendicular to the longitudinal direction, and first and second outer surfaces that are spaced from each other along a transverse direction that is substantially perpendicular to each of the longitudinal direction and the lateral direction; a leading end and a trailing end opposite the leading end along a longitudinal direction, the leading end configured to be inserted into a receptacle of a complementary electrical connector in a mating direction that is oriented along the longitudinal direction, first and second sides spaced from each other along a lateral direction that is substantially perpendicular to the longitudinal direction, and first and second outer surfaces that are spaced from each other along a transverse direction that is substantially perpendicular to each of the longitudinal direction and the lateral direction; a plurality of electrical signal traces at the first surface and defining a mating end, the electrical signal traces arranged in pairs of immediately adjacent signal traces along the lateral direction a plurality of electrical ground traces at the first surface and defining mating ends and termination ends opposite the mating ends along the longitudinal direction, the electrical ground traces defining pairs of immediately adjacent ground traces along the lateral direction, wherein respective pairs of ground traces are disposed between pairs of immediately adjacent signal traces; a plurality of electrically conductive bridges that are electrically and mechanically connected to first and second ground traces of respective pairs of immediately adjacent ground traces that are disposed between immediately adjacent pairs of signal traces, thereby commoning the first and second ground traces of each of the respective pairs of immediately adjacent ground traces in a plane that is defined by the longitudinal direction and the lateral direction, wherein the electrically conductive bridges are disposed at the first outer surface, the electrically conductive bridges are isolated from all signal traces, and the electrically conductive bridges do not contact each other; an electrically conductive ground plate disposed between the first surface and the second surface, wherein the electrically conductive ground plate is aligned with the mating ends of the ground traces along the transverse direction; and electrically conductive vias that extend from respective ones of the bridges to the electrically conductive ground plate.