Communications Connectors Having Printed Circuit Boards that Include Floating Image Planes

• US 20140206240A1
• Filed: 03/14/2013
• Published: 07/24/2014
• Est. Priority Date: 01/23/2013
• Status: Active Grant

• Current Assignee: CommScope Inc. (CommScope Holding Company, Inc.)
• Original Assignee: CommScope Inc. (CommScope Holding Company, Inc.)
• Inventors: Schumacher, Richard A., Enge, Ryan E., Larsen, Wayne D., Moffitt, Bryan S., Pharney, Julian
• Granted Patent: US 8,915,756 B2
• Time in Patent Office: Days
• US Class Current: 439/676
• CPC Class Codes: H01R 13/6461 Means for preventing cross-talk
• CPC Class Codes: H01R 13/6466 on substrates, e.g. printed circuit boards [PCB]
• CPC Class Codes: H01R 13/6473 Impedance matching
• CPC Class Codes: H01R 24/64 for high frequency, e.g. RJ 45
• CPC Class Codes: H05K 1/0219 Printed shielding conductors for shielding around or between signal conductors, e.g. coplanar or coaxial printed shielding conductors
• CPC Class Codes: H05K 1/0228 Compensation of cross-talk by a mutually correlated lay-out of printed circuit traces, e.g. for compensation of cross-talk in mounted connectors balanced signal pairs H05K1/0245
• CPC Class Codes: H05K 1/024 Dielectric details, e.g. changing the dielectric material around a transmission line
• CPC Class Codes: H05K 1/0245 Lay-out of balanced signal pairs, e.g. differential lines or twisted lines
• CPC Class Codes: H05K 1/117 Pads along the edge of rigid circuit boards, e.g. for pluggable connectors
• CPC Class Codes: H05K 2201/0187 with regions of different dielectrics in the same layer, e.g. in a printed capacitor for locally changing the dielectric properties
• CPC Class Codes: H05K 2201/0191 wherein the thickness of the dielectric plays an important role
• CPC Class Codes: H05K 2201/09672 Superposed layout, i.e. in different planes parallel traces in one plane H05K2201/09236
• CPC Class Codes: H05K 2201/09727 Varying width along a single conductor; Conductors or pads having different widths
• CPC Class Codes: H05K 2201/09781 Dummy conductors, i.e. not used for normal transport of current; Dummy electrodes of components
• CPC Class Codes: H05K 2201/1034 Edge terminals, i.e. separate pieces of metal attached to the edge of the PCB tab H05K2201/0397
• CPC Class Codes: H05K 2201/10356 Cables

Abstract

Communications connectors include a housing and a printed circuit board that is at least partially mounted in the housing that has a plurality of conductive paths that are arranged in pairs to form a plurality of differential transmission lines. These connectors further include a plurality of contacts, each of which is electrically connected to a respective one of the conductive paths of the printed circuit board. The printed circuit board further includes at least a first floating image plane that is located between a top surface and a bottom surface thereof, the floating image plane being electrically isolated from the plurality of conductive paths.

Claims

1. A communications connector comprising:

a housing;

a printed circuit board that has a top surface, a bottom surface and a plurality of conductive paths that are arranged in pairs to form a plurality of differential transmission lines, the printed circuit board being at least partially mounted in the housing;

a plurality of contacts, where each of the contacts is electrically connected to a respective one of the conductive paths of the printed circuit board,

wherein the printed circuit board further includes at least a first floating image plane that is located between the top surface and the bottom surface of the printed circuit board, the floating image plane being electrically isolated from the plurality of conductive paths.

2. The communications connector of claim 1, the printed circuit board further comprising a second floating image plane.

3. The communications connector of claim 1, wherein the second floating image plane is electrically isolated from the first floating image plane.

4. The communications connector of claim 3, wherein the first floating image plane is on a first interior layer of the printed circuit board and the second floating image plane is on a second interior layer of the printed circuit board that is different from the first interior layer.

5. The communications connector of claim 4, wherein the first floating image plane is adjacent the top surface of the printed circuit board and the second floating image plane is adjacent the bottom surface of the printed circuit board.

6. The communications connector of claim 1, wherein the communications connector comprises an RJ-45 jack or the communications connector comprises an RJ-45 plug, that is combined with a communications cable to form a patch cord.

7. The communications connector of claim 1, wherein a first of the differential transmission lines includes an imbalanced region, and wherein the first floating image plane is biased to couple more strongly to a first of the conductive paths of the first differential transmission line to compensate for the imbalanced region.

8. The communications connector of claim 1, wherein the conductive paths of a first of the differential transmission lines connect to the respective contacts of a first pair of the contacts and the conductive paths of a second of the differential transmission lines connect to the respective contacts of a second first pair of the contacts, wherein each contact includes a contact region that is designed to mate with a respective one of a plurality of contacts of a mating communications connector, wherein the contact regions of the first pair of contacts are sandwiched between the contact regions of the second pair of contacts, and wherein the second differential transmission line includes a first section adjacent the second pair of contacts where the conductive paths are spaced farther apart from each other than are the conductive paths in a second section of the second differential transmission line, and wherein the first floating image plane is positioned to lower the impedance of the first section of the second differential transmission line.

9. The communications connector of claim 1, wherein the conductive paths of a first of the differential transmission lines connect to the respective contacts of a first pair of the contacts and the conductive paths of a second of the differential transmission lines connect to the respective contacts of a second first pair of the contacts, wherein each contact includes a contact region that is designed to mate with a respective one of a plurality of contacts of a mating communications connector, wherein the contact regions of the first pair of contacts are sandwiched between the contact regions of the second pair of contacts, and wherein the second differential transmission line includes a first section adjacent the second pair of contacts where the conductive paths are spaced farther apart from each other than are the conductive paths in a second section of the second differential transmission line, and wherein the first floating image plane is positioned to raise the impedance of the second section of the second differential transmission line.

10. The communications connector of claim 1, wherein the printed circuit board is a flexible printed circuit board.

11. The communications connector of claim 2, wherein the printed circuit board has a front edge, a back edge, and first and second side edges, and the first floating image plane extends closer to the first side of the printed circuit board than do any of the plurality of differential transmission lines.

12. The communications connector of claim 11, wherein the first floating image plane also extends closer to the second side of the printed circuit board than do any of the plurality of differential transmission lines.

13. The communications connector of claim 1, wherein a first of the differential transmission lines has a first section where the pair of conductive paths are closely spaced and a second section where the pair of conductive paths are spaced farther apart than in the first section, and wherein the first floating image plane extends under the first section of the first of the differential transmission lines and substantially does not extend under the second section of the first of the differential transmission lines.

14. The communications connector of claim 1, wherein the first floating image plane includes at least a first gap that is positioned above or below a first of the differential transmission lines.

15. The communications connector of claim 14, wherein the first gap acts as a common mode filter on the first of the differential transmission lines.

16. The communications connector of claim 1, wherein the first floating image plane is interposed between a first differential transmission line on the top surface of the printed circuit board and a second differential transmission line on the bottom surface of the printed circuit board, the communications connector further comprising at least one offending crosstalk circuit that injects crosstalk between first and second of the differential transmission lines.

17. A communications connector comprising:

a housing;

a printed circuit board that has first and second input terminals that are electrically connected to respective first and second wires of a communications cable, first and second conductive paths that are electrically connected to the respective first and second input terminals, the first and second conductive paths forming a differential transmission line, and first and second contacts that are electrically connected to the respective first and second conductive paths, the printed circuit board being at least partially mounted in the housing;

wherein the printed circuit board further includes at least a first floating image plane, and wherein the floating image plane includes at least one gap underneath the differential transmission line.

18. The communications connector of claim 17, wherein the at least one gap acts as a common mode filter on the differential transmission line.

19. A communications connector comprising:

a housing;

a printed circuit board that has a top surface, a bottom surface and a plurality of conductive paths that are arranged in pairs to form a plurality of differential transmission lines, the printed circuit board being at least partially mounted in the housing;

a plurality of contacts, where each of the contacts is electrically connected to a respective one of the conductive paths of the printed circuit board,

wherein the printed circuit board further includes a first image plane and a second image plane that are each located between the top surface and the bottom surface of the printed circuit board, the first and second image planes being connected to a reference voltage via a ground connection.

20. The communications connector of claim 19, wherein a first of the differential transmission lines includes an imbalanced region, and wherein the first image plane is biased to couple more strongly to a first of the conductive paths of the first differential transmission line to compensate for the imbalanced region.