High density electrical connector with improved grounding bus

An electrical connector comprising:

• a dielectric frame defining a receiving cavity;
• and
• a spacer received in the receiving cavity, the spacer including a plurality of wafers defining a plurality of tunnels between every two adjacent wafers for accommodating printed circuit substrates therein, each wafer having a dielectric body, a plurality of signal terminals retained in the dielectric body, each signal terminal forming a contact point for conductively contacting a signal trace formed on a corresponding printed circuit substrate, and a grounding bus covering the dielectric body and having at least one resilient arm having an arc free end for conductively contacting with a grounding trace formed on the corresponding printed circuit substrate;
• wherein the arc free end of the at least one resilient arm is located higher than the contact point of each signal terminal so that the at least resilient arm conductively contact with the grounding trace before the signal terminals conductively contact with the signal traces of the corresponding printed circuit substrate;
• wherein the grounding bus has a body plate covering a side surface of the dielectric body of each wafer;
• wherein the grounding bus has a pair of resilient arms extending upwardly and convergently from opposite sides of the body plate of the grounding bus;
• wherein each resilient arm forms an arc free end extending out of another side surface opposite to the side surface of the dielectric body for conductively contacting the grounding trace of the corresponding printed circuit substrate;
• wherein the arc free ends of the resilient arms are located higher than the contact points of the signal terminals and thus adapted to firstly conductively contact the grounding trace of the corresponding printed circuit substrate before the contact points of the signal terminals are adapted to conductively contact the signal trace of the corresponding printed circuit substrate;
• wherein the body plate of the grounding bus further forms a plurality of resilient ribs for electrically connecting with the corresponding printed circuit substrate and a plurality of grounding tails for insertion into a circuit board.