Printed circuit boards for communications connectors having openings that improve return loss and/or insertion loss performance and related connectors and methods
Printed circuit boards for communications connectors are provided that include a dielectric substrate formed of a first insulative material having a first dielectric constant. First and second pairs of input terminals and first and second pairs of output terminals are provided on the dielectric substrate. A first differential transmission line electrically connect the first pair of input terminals to the first pair of output terminals, and a second differential transmission line electrically connect the second pair of input terminals to the second pair of output terminals. The dielectric substrate includes an opening that is positioned between the conductive paths of the first differential transmission line, the opening containing a second insulative material having a second dielectric constant.
1. A communications connector, comprising:
first through fourth pairs of input contacts;
first through fourth pairs of wire connection contacts;
a printed circuit board that comprises a dielectric substrate formed of a first dielectric material that has a first dielectric constant and first through fourth differential transmission lines that electrically connect the first through fourth pairs of input contacts to the respective first through fourth pairs of wire connection contacts;
wherein the printed circuit board includes a first opening that is positioned between a first conductive path of the first differential transmission line and a first conductive path of the third differential transmission line, and a second opening that is positioned between a second conductive path of the first differential transmission line and a second conductive path of the third differential transmission line, and
wherein the first opening is filled with a second dielectric material having a second dielectric constant that is different from the first dielectric constant and the second opening is filled with a third dielectric material having a third dielectric constant that is different from the first dielectric constant.
2. The communications connector of claim 1 , wherein the first and second conductive paths of the first differential transmission line are routed between the first and second openings.
3. The communications connector of claim 1 , wherein the second and third dielectric materials comprise air.
4. The communications connector of claim 1 , wherein the first pair of input contacts are between the third pair of input contacts.
5. The communications connector of claim 1 , wherein the communications connector comprises an RJ-45 plug.
6. The communications connector of claim 1 , wherein the second dielectric constant is less than the first dielectric constant and wherein the third dielectric constant is less than the first dielectric constant.
7. The communications connector of claim 1 , wherein the printed circuit board comprises a multi-layer printed circuit board, and wherein the first and second openings each extend all of the way through the printed circuit board.
8. The communications connector of claim 1 , wherein the printed circuit board includes at least one conductive via that is between the first and second openings.
9. The communications connector of claim 1 , wherein input contacts comprise plug blades and the wire connection contacts comprise solder pads on the printed circuit board.
10. A communications connector, comprising:
first through fourth pairs of input contacts;
first through fourth pairs of wire connection contacts;
a printed circuit board that comprises a dielectric substrate formed of a first dielectric material that has a first dielectric constant and first through fourth differential transmission lines that electrically connect the first through fourth pairs of input contacts to the respective first through fourth pairs of wire connection contacts;
wherein the printed circuit board includes a first inductive crosstalk circuit where a first conductive path of the first differential transmission line is routed immediately adjacent a first conductive path of the third differential transmission line, and
wherein the printed circuit board includes an opening that is filled with a second dielectric material having a second dielectric constant that is different from the first dielectric constant, the opening being immediately adjacent the first inductive crosstalk circuit.
11. The communications connector of claim 10 , wherein the second dielectric constant is less than the first dielectric constant.
12. The communications connector of claim 10 , wherein the printed circuit board further includes a second inductive crosstalk circuit where a second conductive path of the first differential transmission line is routed immediately adjacent a second conductive path of the third differential transmission line, and wherein the opening is between the first and second inductive crosstalk circuits.
13. The communications connector of claim 12 , wherein the first and second inductive crosstalk circuits each, inject offending inductive crosstalk between the first and third differential transmission lines.
14. The communications connector of claim 12 , wherein the input contacts comprise plug blades and the opening is immediately adjacent the plug blades.
15. The communications connector of claim 12 , wherein the first pair of input contacts are between the third pair of input contacts.
16. The communications connector of claim 12 , wherein the opening comprises an oblong opening that extends all the way through the printed circuit board, and wherein the second dielectric material is air.