Printed circuit board for RF connector mounting
An RF connector module and associated printed circuit board providing high isolation and controlled impedance at RF frequencies. The connector module may be manufactured using conventional manufacturing techniques, such as stamping, insert molding, multi-shot molding and interference fit between components, to provide low cost. A connector module constructed with these techniques may implement a co-planar waveguide structure, with conductive shields for isolation and lossy material to enforce co-planar propagation modes. The printed circuit board may similarly be manufactured using conventional manufacturing techniques, including drilling to form vias. As a result, an interconnection system may be manufactured with low cost. These techniques may be applied to provide performance, including in the form of isolation between RF signals, comparable to that provided by more expensive components.
1. A printed circuit board comprising a footprint for an RF connector module, the printed circuit board comprising:
a matrix comprising material of a first dielectric constant;
a signal trace supported by the matrix;
a conductive structure, parallel to and isolated from the signal trace by the matrix;
a first via connected to the signal trace within the printed circuit board;
a plurality of second vias electrically coupled through the conductive structure, the plurality of second vias being disposed around the first via;
a plurality of third vias, the third vias being disposed in a region of the printed circuit board between the first via and the plurality of second vias, the third vias have a second dielectric constant different than the first dielectric constant.
2. The printed circuit board of claim 1 , wherein the plurality of second vias are spaced the same distance from the first via.
3. The printed circuit board of claim 2 , further comprising a plurality of micro vias disposed in first column and a second column, parallel to the first column, the first column and the second column being on opposing sides of the first via.
4. The printed circuit board of claim 3 , wherein:
the printed circuit board comprises a first signal launch region comprised of:
the signal trace;
the first via;
the plurality of second vias; and
the plurality of third vias; and
the printed circuit board further comprises a second, like signal launch region, wherein the first via of the second signal launch region is disposed between the first column and the second column.
5. The printed circuit board of claim 4 , wherein the first via, the second vias and the third vias are sized and positioned to provide an impedance in the first signal launch region and the second signal launch region of between 40Ω and 80Ω.
6. The printed circuit board of claim 3 , in combination with an RF connector module, wherein:
the RF connector module comprises:
a lead frame providing a coplanar waveguide structure, the lead frame comprising:
a signal conductor, the signal conductor comprising a contact tail; and
a plurality of ground conductors disposed adjacent the signal conductor, the plurality of ground conductors comprising a plurality of contact tails; and
at least one shield member parallel to the lead frame;
the contact tail of the signal conductor is connected to the first via; and
each of the plurality of contact tails of the plurality of ground conductors is connected to a second via.