US Patent 7722401 Differential electrical connector with skew control

An electrical interconnection system with high speed, differential electrical connectors. The connector is assembled from wafers each containing a column of conductive elements, some of which form differential pairs. A housing for the wafer is formed with regions of higher and lower dielectric constant material. The regions of lower dielectric constant material are selectively positioned adjacent longer signal conductors of the differential pairs. The material may be preferentially placed along curved segments of the differential pair to reduce crosstalk in the connector while reducing skew.