Abstract:
The present invention generally relates to the field of network communication, and more specifically, to the field of communication plugs used in network connectivity. In an embodiment, the present invention is a communication connector that includes: a housing; a printed circuit board (PCB) assembly positioned inside of the housing, the PCB assembly including a first PCB and a second PCB, the PCB assembly further including a plurality of vias, each of the vias extending at least partially through both of the first PCB and the second PCB; and a plurality of plug contacts, each of the plug contacts including an interface section and a base section, the base section being positioned inside one of the vias.

Description:
FIELD OF INVENTION 
     The present invention generally relates to the field of network communication, and more specifically, to the field of communication plugs used in network connectivity. 
     BACKGROUND 
     In network communication, standards are often used to define a particular set of electronic parameters in an effort to provide users with non-proprietary standard platform for connectivity hardware. One such example is the ANSI/TIA-568-C.2 standard provided by TIA which specifies the necessary amount of crosstalk (near end crosstalk (NEXT) and far end crosstalk (FEXT)) that is required to be generated by an RJ45 plug. While achieving each of these parameters alone can be relatively straight forward, meeting all the requirements simultaneously can be quite challenging. 
     For instance, for a given plug, NEXT is proportional to the sum of the capacitive and inductive crosstalk elements, while FEXT is proportional to the difference between the capacitive and inductive crosstalk elements. The more inductive crosstalk that is present within the body of the plug, the less capacitive crosstalk can be placed at the nose of the plug between the plug contacts while still satisfying the TIA NEXT and FEXT requirements. Therefore, the effective distance between the crosstalk and compensation (typically located in a corresponding jack) will increase as the amount of inductive crosstalk within the plug body increases. Conversely, decreasing the amount of inductive crosstalk within the plug body will support a design with more crosstalk between the plug contacts at the nose of the plug, thereby decreasing the distance between the crosstalk and compensation. However, some levels of inductive crosstalk must be maintained in order to meet the FEXT requirements. 
     Furthermore, due to manufacturing tolerances, certain plug designs are more susceptible to parameter fluctuations which may prevent proper operation within the specifications required by a particular standard. 
     These and other concerns create the need for continued improvements in network communication plug designs. 
     SUMMARY 
     Accordingly, at least some embodiments of the present invention are directed towards communication plug designs which enable improved performance tuning. 
     In an embodiment, the present invention is a communication connector that includes: a housing; a printed circuit board (PCB) assembly positioned inside of the housing, the PCB assembly including a first PCB and a second PCB, the PCB assembly further including a plurality of vias, each of the vias extending at least partially through both of the first PCB and the second PCB; and a plurality of plug contacts, each of the plug contacts including an interface section and a base section, the base section being positioned inside one of the vias. 
     These and other features, aspects, and advantages of the present invention will become better-understood with reference to the following drawings, description, and any claims that may follow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a communication system according to an embodiment of the present invention. 
         FIG. 2  illustrates a mated plug/jack assembly. 
         FIGS. 3 and 4  illustrate isometric views of a communication plug according to an embodiment of the present invention. 
         FIGS. 5 and 6  illustrate isometric exploded views of the communication plug according to an embodiment of the present invention. 
         FIG. 7  illustrates a front isometric view of a printed circuit board (PCB) assembly shown in  FIGS. 5 and 6 . 
         FIG. 8  is a cross-section view taken across the section line  8 - 8  of  FIG. 2 . 
         FIG. 9  is an isometric view of a plug contact according to an embodiment of the present invention. 
         FIG. 10  is an isometric view of a plug contact according to an embodiment of the present invention. 
         FIG. 11  is an isometric view of a plug contact according to an embodiment of the present invention. 
         FIG. 12  is an isometric view of a plug contact according to an embodiment of the present invention. 
         FIG. 13  is an isometric view of a plug contact according to an embodiment of the present invention. 
         FIG. 14  is an isometric view of a plug contact according to an embodiment of the present invention. 
         FIG. 15  is an isometric view of a plug contact according to an embodiment of the present invention. 
         FIG. 16  is an isometric view of a plug contact according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a communication system  10  according to an embodiment of the present invention which includes patch panel  12  with jacks  14  and corresponding plug assemblies  16 . Respective cables  20  are terminated to plug assemblies  16 . Once a plug assembly  16  mates with a jack  14  data can flow in both directions through these connectors. Although communication system  10  is illustrated as a patch panel in  FIG. 1 , alternatively it can include other active or passive equipment. Examples of passive equipment can be, but are not limited to, modular patch panels, punch-down patch panels, coupler patch panels, wall jacks, etc. Examples of active equipment can be, but are not limited to, Ethernet switches, routers, servers, physical layer management systems, and power-over-Ethernet equipment as can be found in data centers and/or telecommunications rooms; security devices (cameras and other sensors, etc.) and door access equipment; and telephones, computers, fax machines, printers and other peripherals as can be found in workstation areas. Communication system  10  can further include cabinets, racks, cable management and overhead routing systems, and other such equipment. 
     With the patch panel  12  removed,  FIG. 2  illustrates the network jack  14  and the RJ45 plug assembly  16  in a mated configuration, and  FIGS. 3-4  illustrate the network RJ45 plug assembly  16  by itself with  FIG. 4  being rotated 180° about the central axis of cable  20  relative to  FIG. 3 . 
     As shown in the exploded views of the plug  16  in  FIGS. 5 and 6 , the plug includes non-conductive front housing  26 , top shell  28 , bottom shell  30 , PCB assembly  32  (which includes plug contacts  34  [each having an interface section  31  and a base section  33 ], first PCB  38 , second PCB  39 , cable over molding  40 , and conductive pair manager  42 ) and bend radius control boot  45 . Plug  16  can be used to terminate cable  20  as shown in the figures. 
     During the assembly, bend radius control boot  45  is positioned over cable  20 . Then the cable is dressed such that each conductor  46  pair is positioned in separate electrically isolated quadrants on conductive pair manager  42 . Then conductors  46  of cable  20  are attached to first PCB  38  through pads  60  (illustrated more clearly in  FIG. 7 ). Conductors  46  are shown attached to first PCB  38  through a soldered connection; however other non-limiting means of connecting conductors to a PCB may be used. 
       FIG. 7  is a front isometric view of PCB assembly  32 . Plug contacts  34  mechanically and electrically join first PCB  38  to second PCB  39  by plated through hole vias  37 . Each of the plug contacts is positioned such that its base section  33  extends into a respective via (traversing the first and second PCBs) with the interface section  31  remaining exposed in order to make contact with plug interface contacts of a corresponding jack through the mating interface  35 . Plug contacts  34  are designed to be small in profile so as to reduce electromagnetic coupling between any one plug contact  34  and the remaining seven plug contacts  34 . Plug contacts  34  are also designed to be small in profile to keep a short distance between second PCB  39  and the mating interface  35  between plug contact  34  and jack contact  61  (see  FIG. 8  which is a cross-section view taken along section line  8 - 8  of  FIG. 2 ). Given the low profile of the plug contacts, there may not be enough electromagnetic coupling between neighboring plug contacts  34  and vias  37  to have an RJ45 plug compliant to the crosstalk magnitude requirement of ANSI/TIA-568-C.2. Therefore, additional crosstalk coupling may need to be inserted into first PCB  38  and/or second PCB  39 . It is desirable to locate the crosstalk coupling loads as close to mating interface  35  as possible to reduce the distance to the crosstalk cancellation circuitry that will likely be implemented in a corresponding jack  14 . 
       FIG. 7  schematically shows the additional crosstalk circuitry for pairs  4 : 5 - 3 : 6 . However, similar coupling can be added for the remaining pair combinations. Additional capacitive coupling C 34  is added second to PCB  39  between plug contact  3  and plug contact  4  (note that the numbering of plug contacts is consistent with plug contact numbering provided by ANSI/TIA-568-C.2, which is incorporated herein by reference in its entirety). Capacitor C 34  can be a discrete capacitor, an embedded capacitor designed into one or more layers on PCB  39 , or generated by some other non-limiting means such as distributed capacitance. To locate capacitor C 34  close to mating interface  35 , capacitor C 34  is on the top layer(s) of second PCB  39  (visible layer of  FIG. 7 ). It is also shown to be positioned outside of the transmission line current path. Capacitor C 56  is added to second PCB  39  between plug contact  5  and plug contact  6 . Its magnitude is approximately the same as capacitor C 34  in order to maintain a balanced load. 
     To meet the ANSI/TIA-568-C.2 FEXT requirements, there must exist a level of inductive coupling in addition to the capacitive coupling. In the present embodiment inductive coupling M 34  occurs between vias  37  of plug contact  3  and plug contact  4 . During operation, current travels between pads  60  and mating interface  35 , passing through vias  37  and plug contacts  34 . This current creates the magnetic field that couples to the neighboring transmission lines. Similar to the capacitive coupling, it is still desirable to have the inductive coupling occur close to mating interface. The amount of inductive coupling can be adjusted to a desired level by a variety of ways, including adjusting the diameter of vias, adjusting the thickness of first PCB  38  and second PCB  39 , adjusting the spacing of vias, or other non-limiting means. Inductive coupling M 56  occurs similarly between vias  37  of plug contact  5  and plug contact  6 . The relative closeness of the RJ45 plug&#39;s inductive and capacitive coupling to mating interface  35  aids in meeting the NEXT and FEXT requirements when mated with jack  14 . 
     Using the described two-PCB layout to create PCB assembly  32  may yield certain cost benefits. For example, first PCB  38  can be fabricated from a two-layer stack-up as its purpose can be to transfer the differential signals from pads  60  to vias  37  with minimal crosstalk coupling. On the other hand, second PCB  39  can be fabricated with a four (or more) layer stack-up in order to lump the capacitive coupling elements close to plug contacts  34  and mating interface  35 . It may be cost justified to make the larger PCB  38  out of a lower cost two-layer stack-up and the smaller PCB  39  out of a higher cost four (or more) layer stack-up. 
       FIGS. 9-17  illustrate alternative plug contact embodiments which may be used within communication plug  16 .  FIG. 9  is a front isometric view of plug contact  62  with stacked compliant sections  64  and  65 . Sections  64  and  65  could be same or different dimensions. One of ordinary skill in the art will recognize that vias  37  will need to be sized appropriately to accept the compliant sections  64 . In an embodiment where compliant sections  64  and  65  are non-equal in their dimensions, it is preferable to have section  65  be larger than section  64 . This may allow for easier installation as section  64  will pass with greater ease through the larger via of PCB  39 . 
       FIG. 10  is a front isometric view of plug contact  66 , which has compliant section  68  and straight section  70 . The orientation of compliant section  68  and straight section  70  can be reversed such that in an alternate embodiment compliant section  68  made electrical contact with PCB  38  and straight section  70  made electrical contact with PCB  39 . 
       FIG. 11  is a front isometric view of plug contact  72  which includes an L-shaped cutout  74 . This configuration may be helpful in reducing the cross section area of the plug contact in an attempt to reduce the capacitive coupling between adjacent plug contacts. 
       FIG. 12  shows a modified embodiment of the plug contact shown in  FIG. 11 . In this case, in addition to having the external L-shaped cutout, plug contact  76  includes an interior cutout (slot)  78  which further reduces the contact&#39;s cross-section area. The cutout  78  essentially hollows out a portion of the plug contact. Note that as used herein, references to an “interior cutout” indicate that the hollow area is surrounded by the plug contact along some perimeter. 
       FIGS. 13 and 14  illustrate additional embodiments of plug contacts with interior cutouts.  FIG. 13  is a front isometric view of plug contact  80  that includes slot  82  that extends inside the via of PCB  39  but does not extend down to PCB  38 .  FIG. 14  is a front isometric view of plug contact  84  that includes slot  86  that extends inside of both PCB  38  and PCB  39 . 
       FIGS. 15 and 16  illustrate yet additional embodiments of plug contacts. These embodiments are directed towards providing compression during installation without the usage of compliant pins.  FIG. 15  is a front isometric view of plug contact  92  that includes arms  94  that flex outward after installation to ensure contact with both PCB  38  and PCB  39 . In this embodiment, the hinging section which links both arms is located at the end of the plug contact that is proximate the mating section.  FIG. 16  is a front isometric view of plug contact  96  that includes arm  98  that flexes outward and away from the base  100  after installation to ensure contact with both PCB  38  and PCB  39 . In this embodiment, the hinging section which links both the arm  98  and the base  100  is located at the end of the plug contact that is opposite of the end with the mating section. Although both plug contact  92  and  96  apply pressure during installation for added electrical reliability, soldering or other non-limiting connection methods may be used as well. 
     Note that while this invention has been described in terms of several embodiments, these embodiments are non-limiting (regardless of whether they have been labeled as exemplary or not), and there are alterations, permutations, and equivalents, which fall within the scope of this invention. For example, while references have been made to rigid PCBs, one of ordinary skill in the art would recognize that the use of flexible PCBs or combinations of flex/rigid PCBs would also be within the scope of the disclosure. Moreover, those of ordinary skill will recognize that embodiments of the present invention can be applied to and/or implemented in a variety of shielded communications cables, including without limitation CAT5E, CAT6, CAT6A, CAT7, CAT8, and other twisted pair Ethernet cable, as well as other types of cable. Furthermore, it should be understood that various plug contact designs are not limited to working only with the circuit board designs/configurations described herein, and may instead be implemented in any variety of other connectors. Additionally, the described embodiments should not be interpreted as mutually exclusive, and should instead be understood as potentially combinable if such combinations are permissive. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present invention. It is therefore intended that claims that may follow be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.