Abstract:
Embodiments of the present invention relate to designs for network jacks which can be used for cable connectivity. In an embodiment, the present invention is an RJ45 jack that utilizes a thin dielectric film between two layers of PICs that provide crosstalk compensation by way of their geometry. Compensation is achieved by way of capacitor plates which sandwich a thin dielectric film. This allows for the layers of PICs to be in close proximity and achieve higher coupling where desired, allowing a greater amount of compensation to occur close to the plug/jack contact point. This can have the effect of moving compensation closer to the plug/jack contact point, which in turn may reduce the amount of compensation needed further along the data path.

Description:
FIELD OF INVENTION 
     Embodiments of the present invention generally relate to the field of network communication, and more specifically, to designs for network jacks which can be used for cable connectivity. 
     BACKGROUND 
     It is known by those skilled in the art that network connectivity components such as RJ45 plugs and jacks produce and cancel, respectively, a predetermined amount of crosstalk. It is equally known that in order to more effectively cancel crosstalk within an RJ45 jack, compensation circuitry must be moved as close to the plug/jack mating interface as possible. 
     One method of achieving this is to use a flexible printed circuit board which is connected to plug interface contacts (PICs) of the jack at a point that is relatively close to the plug jack mating interface. An example of such configuration is provided in U.S. Patent Application Publication No. 2008/0045090 where FIGS. 15A-15G illustrate an exemplary jack which uses a flexible circuit board with crosstalk compensation circuitry thereon. While effective, this method is costly due to the high cost of flexible circuit boards. 
     Another method of moving crosstalk circuitry close to the plug/jack mating interface is to implement a crossover in some of the contact traces of the jack. An example of such a configuration can be seen in U.S. Patent Application Publication No. 2014/0073195 where crossovers in the PICs are implemented near the mandrel of the sled. Although these crossovers allow the compensation to begin relatively soon after the plug/jack mating interface, it is difficult to obtain a sufficiently desirable amount of coupling therefrom, causing a larger portion of the compensation signal to be generated further away from the plug/jack mating interface to achieve the net compensation signal. 
     In view of the foregoing, there remains a need for improved jack designs which provide appropriate crosstalk cancellation while remaining relatively economical to manufacture. 
     SUMMARY 
     Accordingly, at least some embodiments of the present invention are directed towards improved jack designs which provide appropriate crosstalk cancellation while remaining relatively economical. 
     In an embodiment, the present invention is an RJ45 jack that utilizes a thin dielectric film between two layers of PICs that provide crosstalk compensation by way of their geometry. Compensation is achieved by way of capacitor plates which sandwich a thin dielectric film. This allows for the layers of PICs to be in close proximity and achieve higher coupling where desired, allowing a greater amount of compensation to occur close to the plug/jack contact point. This can have the effect of moving compensation closer to the plug/jack contact point, which in turn may reduce the amount of compensation and/or crosstalk needed further along the data path. 
     In another embodiment, the present invention is a communication jack for mating with a communication plug. The communication jack includes a housing having an aperture for receiving the communication plug, a sled positioned at least partially inside the housing, a first end of the sled being proximate the aperture and having a mandrel, a second end being distal the aperture, a first PICs, each of the first plurality of PICs having a first section extending along a side of the sled and a second section formed around the mandrel, a second plurality of PICs, each of the second plurality of PICs having a first section extending along the side of the sled and a second section formed around the mandrel, and a dielectric film positioned between at least some of the first sections of the first plurality of PICs and at least some of the first sections of the second plurality of PICs, the dielectric film being further positioned between at least some of the second sections of the first plurality of PICs and at least some of the second sections of the second plurality of PICs. 
     In yet another embodiment, the present invention is a communication jack for mating with a communication plug. The communication jack includes a housing having an aperture for receiving the communication plug, the housing further having a plurality of crush ribs, a sled positioned at least partially inside the housing, a first end of the sled being proximate the aperture and having a mandrel, a second end being distal the aperture, a first plurality of PICs, each of the first plurality of PICs having a first section extending along a side of the sled and a second section formed around the mandrel, a second plurality of PICs, each of the second plurality of PICs having a first section extending along the side of the sled and a second section formed around the mandrel, and a dielectric film positioned between at least some of the first sections of the first plurality of PICs and at least some of the first sections of the second plurality of PICs, wherein the crush ribs compress at least some of the first plurality of PICs against the dielectric film. 
     In still yet another embodiment, the present invention is a communication jack for mating with a communication plug. The communication jack includes a housing having an aperture for receiving the communication plug, a sled positioned at least partially inside the housing, a first end of the sled being proximate the aperture and having a mandrel, a second end being distal the aperture, a first plurality of PICs, each of the first plurality of PICs having a first section extending along a side of the sled and a second section formed around the mandrel, a second plurality of PICs, each of the second plurality of PICs having a first section extending along the side of the sled and a second section formed around the mandrel, and a dielectric film positioned between at least some of the first sections of the first plurality of PICs and at least some of the first sections of the second plurality of PICs, wherein at least one of the first plurality of PICs capacitively couples to at least one of the second plurality of PICs via a first capacitive plate positioned on the at least one of the first plurality of PICs and a second capacitive plate positioned on the at least one of the second plurality of PICs, and wherein the first capacitive plate overlaps and extends over the second capacitive plate. 
     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  is a top isometric view of a communication system according to an embodiment of the present invention. 
         FIG. 2  is a bottom isometric view of a jack according to an embodiment of the present invention. 
         FIG. 3  is an exploded bottom isometric view of a jack according to an embodiment of the present invention. 
         FIG. 4  is an exploded front top isometric view of a sled assembly according to an embodiment of the present invention. 
         FIG. 5  is an exploded rear top isometric view the sled assembly of  FIG. 4 . 
         FIG. 6  is a partially transparent front view of the sled assembly of  FIG. 4 . 
         FIG. 7A  is a partially transparent top view of the sled assembly of  FIG. 4 . 
         FIG. 7B  is a detailed view from  FIG. 7A . 
         FIG. 8  is a rear bottom isometric view of a front housing according to an embodiment of the present invention. 
         FIG. 9  shows an isometric cross-section view of the front housing of  FIG. 8  taken about section line  9 - 9 . 
         FIG. 10  shows an isometric cross-section view of a front housing according to an embodiment of the present invention. 
         FIG. 11  shows an isometric cross-section view of a front housing according to an embodiment of the present invention. 
         FIG. 12  is a cross-section view of the communication system of  FIG. 1  taken about section line  12 - 12 . 
     
    
    
     DETAILED DESCRIPTION 
     An exemplary embodiment of the present invention is illustrated in  FIG. 1 , which shows a communication system  10 , which includes a patch panel  12  with jacks  20  and corresponding RJ45 plugs  26 . Once a plug  26  mates with a jack  20  data can flow in both directions through these connectors. Although the communication system  10  is illustrated in  FIG. 1  as having a patch panel, alternative embodiments 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. 
       FIGS. 2 and 3  illustrate jack  20  in greater detail. As shown therein, it includes front housing  32 , sled assembly  34 , printed circuit board (PCB)  42 , insulation displacement contacts (IDCs)  46  and  48 , IDC support  50 , rear housing  54 , and wire cap  55 . Referring to  FIGS. 4 and 5 , sled assembly  34  includes an upper PIC layer  56  comprised of PICs  36   2 ,  36   3 ,  36   4 , and  36   8 , a lower PIC layer  58  comprised of PICs  36   1 ,  36   5 ,  36   6 , and  36   7 , sled  38 , and thin dielectric film  40 . The subscript numbers of PICs represent RJ45 pin positions as defined by ANSI/TIA-568-C.2. 
     During assembly of sled assembly  34 , PICs  36   1 ,  36   5 ,  36   6 , and  36   7  of lower PIC layer  58  are placed into respective PICs slots on sled  38  with shoulders  60  on PICs  36   1 ,  36   5 ,  36   6 , and  36   7  being placed into lower PIC locating slots  64 . When in position, these PICs are formed over the smaller mandrel  68  of sled  38 . A thin dielectric film  40  is placed onto the lower PIC layer  58  with guide holes  41  on dielectric film  40  aligning with guide posts  39  on sled  38 . Next, PICs  36   2 ,  36   3 ,  36   4 , and  36   8  of upper PIC layer  56  are placed into respective PICs slots on sled  38  with shoulders  60  on PICs  36   2 ,  36   3 ,  36   4 , and  36   8  being placed into upper PIC locating slots  62 . When in position, these PICs are formed over the larger mandrel  70  of sled  38  trapping the dielectric film  40  between the upper and lower PIC layers. Note that PICs  36  may be formed around the mandrels immediately as they are placed into their respective positions on sled  38  or they may be formed after both the upper and lower layers have been positioned accordingly. 
     Using the dielectric film  40  allows capacitance plates  66  of upper PIC layer  56  and lower PIC layer  58  to be positioned within approximately 0.002 inch of each other. This can enable greater and/or more precise amount of capacitive and inductive compensative coupling between the two PIC layers while maintaining a barrier therebetween. In the embodiment shown, upper PIC layer  56  and lower PIC layer  58  are a mirror image of each other. This can allow for the use of a single metal stamping process, potentially reducing the overall cost. 
       FIG. 6  shows a partially transparent front view of front sled assembly  34  with PICs  36  formed around PIC mandrels  68  and  70 . Crossover geometry  61  between PICs  36   1  &amp;  36   2 ,  36   4  &amp;  36   5 , and  36   7  &amp;  36   8  signifies the beginning of the crosstalk cancellation circuitry and thus reduces the amount of offending crosstalk produced in PICs  36 . Extending dielectric film  40  into the crossover areas  61  permits the upper and lower PICs to be positioned closer than they would be otherwise, allowing more accurate compensation to occur closer to the plug/jack mating point. The crosstalk cancellation circuitry is shown more clearly in  FIG. 7A  which shows a partially transparent top view of the sled assembly  34  and  FIG. 7B  which shows a detailed view from  FIG. 7A . Note that in  FIG. 7A , PICs  36  are shown as being extended and not yet formed around the mandrels  68  and  70 . 
     To achieve the desired capacitive coupling more precisely, at least some capacitive plates are oversized relative to their corresponding plates. An example of this is illustrated in the detailed view of  FIG. 7B  where plate  71  overlaps plate  73  and extends over it by a distance  75  that is at least 0.001 inches. Implementing such a configuration can allow for maintaining appropriate levels of capacitive coupling while sustaining manufacturing variances which would cause either plate  71  or  73  to be out of exact position. For instance, if distance  75  is 0.005 inches and plate  73  is skewed by 0.002 inches, the overlapping area between the two plates  71  and  73  remains the same, causing the capacitive coupling to remain the same. In an embodiment, distance  75  extends entirely around a given capacitor plate. 
       FIG. 8  shows a rear bottom isometric view of front housing  32  and  FIG. 9  shows an isometric cross-section view of front housing  32  taken about section line  9 - 9  in  FIG. 8 . During assembly of jack  20 , PICs  36  move through housing combs  72  of front housing  32 , which reduces risk of high potential dwell testing (Hipot) failure and increases repeatability of plug insertions. Additionally, crush ribs  74  of front housing  32  press against upper PIC layer  56  to reduce the amount of air between upper PIC layer  56 , dielectric film  40 , and lower PIC layer  58 . Reducing the amount of air between the layers may allow for capacitance plates  66  to more accurately compensate the crosstalk in the jack in order to maintain specified electrical performance. Note that reducing the air gap between capacitance plates  66  may be achieved using many forms of biasing members in the housing. Alternate embodiments of front housings  80  and  84  with alternate crush ribs  82  and  86  are shown in  FIGS. 10 and 11 , respectively. 
     The interaction of plug  26  with jack  20  is shown in a cross-section view of  FIG. 12  taken about section line  12 - 12  in  FIG. 1 . This view illustrates the plug/jack contact point  76  and its location relative to PCB  42  where additional crosstalk compensation circuitry may be implemented. By implementing the crossover sections  61  in combination with the capacitive circuitry comprising of plates  66  and dielectric film  40  relatively close to point  76 , the overall crosstalk compensation requirements are simplified. This occurs because the distance where the offending crosstalk is generated in the PICs is reduced, because the phase delay between the plug/jack contact point  76  and the first stage of compensation is reduced, and because the compensation circuitry that may be positioned further than the PICs (e.g., on PCB  42 ) may potentially have a lower magnitude. 
     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. 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.