An electrical connector including a lead frame assembly of a first
dielectric material that includes a pocket filled with a second
dielectric material. A first ground reference, which may be either a
ground contact or conductor or a virtual ground defined between signal
contacts of a differential signal pair, extends in the first dielectric
material and has a first physical length. A second ground reference
having a different physical length than the first length extends in the
first dielectric material and also through the pocket. The combination of
the length of the second ground reference through the pocket along with
the difference in the dielectric constants associated with the first and
second dielectric materials, provides for equalizing or matching the
electrical lengths of these two references having different physical
lengths. This may aid in reducing slot-line mode of a co-planar
waveguide. The cross-sectional size of the second reference within the
pocket may be altered to provide uniform impedance along the length of
the second reference as well as an impedance matched to the first
conductor.