Communications connectors having frequency dependent communications paths and related methods

Communications connectors are provided that include a plurality of inputs that are arranged as differential pairs of inputs and a plurality of outputs that are arranged as differential pairs of outputs. A plurality of low frequency conductive paths are provided, each of which electrically connects a respective one of the inputs to a respective one of the outputs. These low frequency conductive paths are configured to pass signals having frequencies in a first frequency band while substantially attenuating signals having frequencies in a second frequency band that includes higher frequencies than the first frequency band. A plurality of second conductive paths are also provided. Each of the plurality of second conductive paths is electrically in parallel with at least a portion of a respective one of the low frequency conductive paths.

FIELD OF THE INVENTION

The present invention relates generally to communications connectors and, more particularly, to communications connectors that may exhibit improved performance over a wide frequency range.

BACKGROUND

Computers, fax machines, printers and other electronic devices are routinely connected by communications cables to network equipment such as routers, switches, servers and the like.FIG. 1illustrates the manner in which a computer10may be connected to network equipment20using conventional communications plug/jack connections. As shown inFIG. 1, the computer10is connected by a patch cord11to a communications jack30that is mounted in a wall plate18. The patch cord11comprises a communications cable12that contains a plurality of individual conductors (e.g., insulated copper wires) and first and second communications plugs13,14that are attached to the respective ends of the cable12. The first communications plug13is inserted into a communications jack that is provided in the computer10(this jack is not visible inFIG. 1), and the second communications plug14is inserted into a plug aperture32in the front side of the communications jack30. The contacts or “blades” of the second communications plug14are exposed through the slots15on the top and front surfaces of the second communications plug14and mate with respective contacts of the communications jack30. The blades of the first communications plug13similarly mate with respective contacts of the communications jack that is provided in the computer10.

The communications jack30includes a back-end wire connection assembly34that receives and holds conductors from a cable36. As shown inFIG. 1, each conductor of cable36is individually pressed into a respective one of a plurality of slots provided in the back-end wire connection assembly34to establish mechanical and electrical connection between each conductor of cable36and a respective one of a plurality of conductive paths (not shown inFIG. 1) through the communications jack30. The other end of each conductor in cable36may be connected to, for example, the network equipment20. The wall plate18is typically mounted on a wall (not shown) of a room or office of, for example, an office building, and the cable36typically runs through conduits in the walls and/or ceilings of the building to a room in which the network equipment20is located. The patch cord11, the communications jack30and the cable36provide a plurality of signal transmission paths over which information signals may be communicated between the computer10and the network equipment20. It will be appreciated that typically one or more patch panels, along with additional communications cabling, would be included in the electrical path between the cable36and the network equipment20. However, for ease of description, inFIG. 1the cable36is shown as being directly connected to the network equipment20.

In the above-described communications system, the information signals that are transmitted between the computer10and the network equipment20are typically transmitted over a pair of conductors (hereinafter a “differential pair” or simply a “pair”) rather than over a single conductor. An information signal is transmitted over a differential pair by transmitting signals on each conductor of the pair that have equal magnitudes, but opposite phases, where the signals transmitted on the two conductors of the pair are selected such that the information signal is the voltage difference between the two transmitted signals. The use of differential signaling can greatly reduce the impact of noise on an information signal.

Various industry standards, such as the TIA/EIA-568-B.2-1 standard approved Jun. 20, 2002 by the Telecommunications Industry Association, have been promulgated that specify configurations, interfaces, performance levels and the like that help ensure that jacks, plugs, cables and the like that are produced by different companies will all work together. The most commonly followed of these industry standards specify that each jack, plug and cable segment in a communications system must include a total of eight conductors1-8that are arranged as four differential pairs of conductors. The industry standards specify that, in at least the connection region where the contacts (blades) of a plug mate with the contacts of the jack (referred to herein as the “plug-jack mating region”), the eight conductors are generally aligned in a row. As shown inFIG. 2, under the TIA/EIA 568 type B configuration, conductors4and5inFIG. 2comprise differential pair 1, conductors1and2comprise differential pair 2, conductors3and6comprise differential pair 3, and conductors7and8comprise differential pair 4. Conductors1,3,5and7are referred to as “tip” conductors, and conductors2,4,6and8are referred to as “ring” conductors.

Unfortunately, the industry-standardized connector configuration shown inFIG. 2, which was adopted many years ago, generates a type of noise known as “crosstalk.” As is known to those of skill in this art, “crosstalk” refers to unwanted signal energy that is induced onto the conductors of a first “victim” differential pair from a signal that is transmitted over a second “disturbing” differential pair. The induced crosstalk may include both near-end crosstalk (NEXT), which is the crosstalk measured at an input location corresponding to a source at the same location (i.e., crosstalk whose induced voltage signal travels in an opposite direction to that of an originating, disturbing signal in a different path), and far-end crosstalk (FEXT), which is the crosstalk measured at the output location corresponding to a source at the input location (i.e., crosstalk whose signal travels in the same direction as the disturbing signal in the different path). Both types of crosstalk degrade the information signal on the victim differential pair.

Various techniques have been developed for cancelling out the crosstalk that arises in industry standardized plugs and jacks. Many of these techniques involve including crosstalk compensation circuits in each communications jack that introduce “compensating” crosstalk that cancels out much of the “offending” crosstalk that is introduced in the plug and the plug-jack mating region due to industry-standardized plug-jack interface. In order to achieve high levels of crosstalk cancellation, the industry standards have for many years required that each communication plug introduce defined levels of crosstalk between the four differential pairs, which allows each manufacturer to design the crosstalk compensation circuits in their communications jacks to cancel out these predefined amounts of crosstalk. Typically, the communications jacks use “multi-stage” crosstalk compensation circuits as disclosed, for example, in U.S. Pat. No. 5,997,358 to Adriaenssens et al. (hereinafter “the '358 patent”), as these multi-stage crosstalk compensating schemes can provide significantly improved crosstalk cancellation, particularly at higher frequencies. The entire contents of the '358 patent are hereby incorporated herein by reference as if set forth fully herein.

DETAILED DESCRIPTION

Pursuant to embodiments of the present invention, communications connectors such as RJ-45 plugs, jacks and mated plug-jack connectors are provided that include at least first and second sets of electrically parallel conductive paths. At least one of the first and second sets of conductive paths comprises frequency selective conductive paths that pass signals that are within a first range of frequencies while substantially attenuating signals that are within a second, different range of frequencies. By way of example, in some embodiments, the first set of conductive paths may pass signals at frequencies of about 500 MHz or less, while substantially attenuating signals at higher frequencies. In such embodiments the second set of conductive paths may be designed to pass signals at frequencies exceeding 500 MHz, while substantially attenuating signals at lower frequencies. The first set of conductive paths may be designed to meet applicable industry standards for one or more of NEXT, FEXT, insertion loss, return loss, conversion loss and the like so that the communications connectors will comply with various industry standards. The second set of conductive paths may be designed to have reduced crosstalk along with acceptable insertion loss, return loss, conversion loss and the like for frequencies in the range of, for example, 500 MHz to 3000 MHz or more so as to provide high channel capacity in this higher frequency range. In some embodiments, each conductive path in the first set of conductive paths may be substantially isolated from its parallel conductive path in the second set of conductive paths.

The communications connectors according to certain embodiments of the present invention may include a filter network that may be used to route signals that are input to the communications connector onto the appropriate one(s) of the first and second conductive paths. For example, in some embodiments, low pass or band pass filters may be provided that only allow lower frequency signals onto the low frequency conductive paths, and band pass or high pass filters may be provided that only allow higher frequency signals onto the high frequency conductive paths.

In some embodiments, the communications connector may comprise an RJ-45 plug, and each of the eight communications paths through this RJ-45 plug may split into two different paths, with a low pass filter provided on one of the two paths and a high pass filter provided on the other of the two paths to provide low and high frequency conductive paths. These filters may be implemented for example in one or more printed circuit board mounted integrated circuit chips or as discrete components mounted on a printed circuit board. In some embodiments, first and second low pass filters may be provided on each low frequency conductive path and/or first and second high pass filters may be provided on each high frequency conductive path so as to allow frequency band specific processing to be performed on either or both low frequency signals and/or high frequency signals that are passed through the connector.

In, for example, RJ-45 plug embodiments of the above-described communications connectors, the blades of the plug may be (but need not be) skeletal plug blades or surface contact plug blades that may generate crosstalk levels that are substantially below the predefined crosstalk levels specified in the relevant industry standards. In such embodiments, each low frequency conductive path may have first and second low pass filters included thereon, and additional reactive components such as capacitors may be coupled between certain of the low frequency conductive paths (e.g., between plug blades2and3; blades3and4; blades5and6; and blades6and7). These additional reactive components may be used to intentionally generate additional “offending” crosstalk so that the RJ-45 plug meets the industry standardized crosstalk requirements for the frequency ranges where such crosstalk levels are specified. Corresponding reactive components may be omitted from the high frequency conductive paths so that those paths may have reduced crosstalk levels. In this manner, an industry standards compliant plug may be provided that may also be used to carry high capacity signals in higher frequency bands that fall outside of the industry standards. It will likewise be appreciated that in other embodiments reactive components may be provided on some or all of the high frequency conductive paths, although these components would typically be different in type, size and/or configuration from the reactive components that are provided on the low frequency conductive paths. By way of example, reactive components that generate compensating crosstalk could be provided on some or all of the high frequency conductive paths in some embodiments.

Embodiments of the present invention will now be described with reference to the accompanying drawings, in which exemplary embodiments are shown.

FIG. 3is a block diagram of a communications connector100according to certain embodiments of the present invention. The communications connector100could be, for example, a communications plug (e.g., an RJ-45 plug) or a communications jack (e.g., an RJ-45 jack) or the mated combination of a plug and a jack. As shown inFIG. 3, the communications connector100includes an input contact110. This input contact110may be any appropriate contact for transferring a communications signal into the communications connector100. Exemplary contacts that may be used as the input contact110include insulation displacement contacts (IDCs), insulation piercing contacts, plug blades, jackwire contacts, pad contacts, clasp contacts, etc. The input contact110is electrically connected to a signal path splitter circuit120. As shown inFIG. 3, the signal path splitter circuit120splits the conductive path from the input contact110into two electrically parallel conductive paths.

In some embodiments, the first of the two conductive paths output by the signal path splitter120comprises a first frequency selective conductive path130, and the second of the two conductive paths output by the signal path splitter120comprises a second frequency selective conductive path140. Both the first and second frequency conductive paths130,140are input to a signal path combiner150. The signal path combiner150combines any signals that are present on the first and second frequency selective conductive paths130,140and provides this combined signal to an output contact160. The output contact160is used to output the combined signal from the communications connector100to a cable, a connector, a device or the like. Exemplary contacts that may be used as the output contact160include insulation displacement contacts (IDCs), insulation piercing contacts, plug blades, jackwire contacts, pad contacts, clasp contacts, plated-thru-holes that are routed in half, etc. It will be appreciated that signals may often travel in both directions through communications connector100, so if the direction of the signal is reversed the output contact160will act as an input contact and the input contact110will act as an output contact.

The first frequency selective conductive path130may be designed to pass signals at frequencies in one or more first frequency bands while substantially attenuating signals in other frequency bands. By way of example, in some embodiments, the first frequency selective conductive path130may be designed to pass signals at frequencies of less than about 500 MHz while substantially attenuating signals at higher frequencies. The second frequency selective conductive path140may be designed to pass signals at frequencies in one or more second frequency bands while substantially attenuating signals in other frequency bands. By way of example, in some embodiments, the second frequency selective conductive path130may be designed to pass signals at frequencies higher than about 600 MHz while substantially attenuating signals at lower frequencies. It will be appreciated that in some embodiments one of the first or second frequency selective conductive paths130,140may be designed to pass signals at all frequencies.

As will be explained in more detail below, the provision of the first or second frequency selective conductive paths130,140allows different signal processing to be performed on signals in different frequency ranges. By way of example, crosstalk generating and/or crosstalk compensation circuits may be provided on one of the first or second frequency selective conductive paths130,140and not provided on the other. As will be discussed in more detail below, the performance of the communication connector100may be improved over a wider frequency range as compared to prior art connectors by transmitting signals at certain predefined frequency ranges over the first frequency selective conductive path130while transmitting signals at other frequencies over the second frequency selective conductive path140.

As discussed above, many communications connectors such as RJ-45 plugs and jacks include more than one conductive path therethrough.FIG. 4is a circuit diagram of a communications connector200according to certain embodiments of the present invention that includes multiple conductive paths that may carry multiple signals. The communications connector200may comprise, for example, an RJ-45 communications plug that has eight conductive paths that are configured to carry four differential signals or an RJ-45 jack that has eight conductive paths that are configured to carry four differential signals. As is discussed below, in the particular embodiment depicted inFIG. 4, the connector200includes a plurality of low frequency conductive paths and a plurality of high frequency conductive paths, and provides additional signal processing for the signals that are passed through the connector200via the low frequency conductive paths.

As shown inFIG. 4, a communications cable202is provided that includes at least eight conductors204. Each one of the conductors204is terminated into a respective one of a plurality of input contacts210of the connector200. Each input contact210may comprise, for example, an IDC or an insulation piercing contact. A plurality of conductive paths212are provided that electrically connect each input contact210to a signal path splitter circuit220. In some embodiments, the signal path splitter circuit220may be coupled directly to the input contacts210so that some or all of the conductive paths212may be omitted.

As shown inFIG. 4, the signal path splitter circuit220splits each of the conductive paths212that are input thereto into two conductive paths224,226. The signal path splitter circuit220may comprise, for example, a plurality of conductive traces, each of which has another conductive trace branching off therefrom. Each of the conductive paths224that comprises the first output from the signal path splitter circuit220is coupled to a corresponding one of a plurality of low frequency conductive paths230. As shown inFIG. 4, the low frequency conductive paths230are formed using a first bank of low pass filters (the bank of low pass filters is labeled “LPF” in the drawings)232and a second bank of low pass filters236. The first and second banks of low pass filters232,236may each comprise, for example, either a plurality of individual low pass filters or, alternatively, an integrated circuit chip that includes a low pass filter for each of the low frequency conductive paths230. It will also be appreciated that in some embodiments the low pass filters232,236could be replaced with band pass filters that, for example, attenuate very low frequency signals (e.g., signals at frequencies below 1 MHz) and also attenuate signals above a certain cut-off frequency (e.g., 500 MHz).

As is further shown inFIG. 4, one or more signal conditioning circuits234are provided along the low frequency conductive paths230. By way of example, crosstalk compensation circuits, crosstalk generation circuits, return loss compensation circuits and the like may be provided that will condition the signals that are passed along the low frequency conductive paths230. The provision of low frequency conductive paths230and high frequency conductive paths240allows for different signal conditioning to be applied to input signals that are in different frequency ranges.

Each of the conductive paths226that comprises the second output from the signal path splitter circuit220is coupled to a corresponding one of a plurality of high frequency conductive paths240. As shown inFIG. 4, the high frequency conductive paths240are formed using a bank of high pass filters242(the bank of high pass filters is labeled “HPF” in the drawings). In the depicted embodiment, no special signal conditioning is applied to the high frequency signals, and hence no signal conditioning circuit is provided along the high frequency conductive paths240. Additionally, in the depicted embodiment, only a single bank of high pass filters is provided. The bank of high pass filters242may comprise, for example, a plurality of individual high pass filters or may instead comprise an integrated circuit chip that includes a high pass filter for each of the conductive paths240. It will also be appreciated that some or all of the high pass filters could be replaced with band pass filters that pass signals within a band of frequencies above a certain cut-off frequency (e.g., 500 MHz), but attenuate signals below the cut-off frequency and also attenuate signals at frequencies above another cut-off frequency (e.g., 2 GHz, 3 GHz, etc.).

A plurality of conductive paths238connect each low frequency conductive path230to a signal path combiner circuit250. A plurality of conductive paths244connect each high frequency conductive path240to the signal path combiner circuit250. As shown inFIG. 4, the signal path combiner circuit250combines each of the conductive paths238with its counterpart (i.e., parallel) conductive path244. A plurality of conductive paths252are output from the signal path combiner circuit250and connected to respective ones of a plurality of output contacts260. The output contacts260may comprise, for example, plug blades, jackwire contacts, etc.

As shown inFIG. 4, each signal that is input to the connector200is split into two components that are transmitted through the connector200on electrically parallel low frequency and high frequency conductive paths. The signals are then recombined and output from the connector200. Different types of signal processing may be performed on the electrically parallel low frequency and high frequency conductive paths, as will be discussed in more detail below.

Pursuant to some embodiments of the present invention, communications connectors may be provided that use electrically parallel low frequency and high frequency conductive paths to provide improved crosstalk performance. For example, in some embodiments, communications plugs are provided that exhibit improved crosstalk performance at high frequencies (e.g., frequencies greater than 500 MHz) while still fully complying with the industry standards for crosstalk levels at frequencies below 500 MHz.

By way of background, various industry standards specify the amount of crosstalk (as a function of frequency) that must be present between each of the differential pairs of a communications plug for the plug to be compliant with the standard. For example, Table C.6 of Section C.4.10.3 of the TIA/EIA-568-C.2 or “Category 6A” standard sets forth ranges for the pair-to-pair NEXT and FEXT levels that a plug must meet to be compliant with the standard. Other industry standards (e.g., the Category 6 standard) have similar requirements. Thus, while techniques are available that could be used to design RJ-45 communications plugs that have lower pair-to-pair NEXT and FEXT levels—which levels would be easier to compensate for in the communications jacks—the installed base of existing RJ-45 communications plugs and jacks have offending crosstalk levels and crosstalk compensation circuits, respectively, that were designed based on the industry standard specified levels of plug crosstalk. Consequently, lowering the crosstalk in the plug has generally not been an available option for further reducing crosstalk levels to allow for communication at even higher frequencies, as such lower crosstalk jacks and plugs would typically (without special design features) exhibit reduced performance when used with the industry-standard compliant installed base of plugs and jacks.

Pursuant to embodiments of the present invention, communications plugs are provided that may be designed to fully comply with the applicable industry standards (e.g., the pair-to-pair NEXT and FEXT levels) at the frequency ranges specified in the standards. However, by providing, for example, separate (electrically parallel) low frequency and high frequency conductive paths, these plugs may be designed to exhibit lower crosstalk levels at higher frequencies (e.g., frequencies above 500 MHz, above 600 MHz, above 1 GHz, etc.), and thus may exhibit improved performance at higher frequencies as compared to conventional communications plugs. An exemplary RJ-45 communications plug300according to embodiments of the present invention that provides such enhanced performance will now be discussed with respect toFIGS. 5-8.FIG. 5is a perspective view of the communications plug300.FIGS. 6 and 7are a top perspective view and a bottom perspective view, respectively, of the communications plug300with the plug housing removed.FIG. 8is a schematic plan view of the printed circuit board of the communications plug300.

As shown inFIG. 5, the communications plug300includes a dielectric housing310. The top and front faces of the housing310include a plurality of longitudinally extending slots314that expose a plurality of plug contacts or “blades”340. A separator316is positioned within an opening in the rear face of the housing310. A jacketed communications cable (not shown) that includes four twisted pairs of insulated conductors may be received through the opening in the rear face of the housing310and the jacket may be placed over the separator316. Each twisted pair of conductors of this cable is received within one of the four quadrants of the separator316. A rear cap318that includes a cable aperture319locks into place over the rear face of housing310after the communications cable has been inserted into the rear face of the housing310.

As shown inFIGS. 5-7, a termination manager320and a printed circuit board330are each disposed within the housing310. The termination manager320has a front opening322that receives the rear end of the printed circuit board330. In the pictured embodiment, the printed circuit board330comprises a multi-layer printed circuit board. Eight plug blades340are mounted near the forward top edge of the printed circuit board330so that the blades340-1through340-8can be accessed through the slots314in the top and front faces of the housing310(seeFIG. 5). Note that inFIGS. 5-8groups of related elements such as the plug blades340-1through340-8may be individually identified (e.g., plug blade340-3) or may be collectively referred to using the common reference numeral that is to the left of the dash (e.g., the plug blades340-1through340-8may be collectively referred to as plug blades340).

The plug blades340are generally aligned in side-by-side fashion in a row. In the depicted embodiment, each of the eight plug blades340comprises a wire that is mounted into spaced-apart apertures in the printed circuit board330. A first end of each wire is mounted in a first aperture in the printed circuit board330, and a second end of each wire340is mounted in a second aperture in the printed circuit board330. Each wire forms a “skeletal” plug blade340. By “skeletal” it is meant that the plug blade340has an outer skeleton or shell and a hollow or open area in the center. Thus, in contrast to traditional plug blades for RJ-45 style plugs, each blade340has an open interior. The use of such skeletal plug blades340may facilitate reducing crosstalk levels between adjacent plug blades340by reducing the capacitive and/or inductive coupling between adjacent plug blades340of different differential pairs. As shown inFIG. 6, each plug blade340includes a U-shaped projection that extends in the longitudinal direction of the plug300. The U-shaped projections on adjacent plug blades340point in opposite directions. This arrangement may further reduce the amount of crosstalk generated between adjacent plug blades340.

As shown inFIGS. 6 and 7, eight output contacts332are mounted at the rear of printed circuit board330, with four of the output contacts332(seeFIG. 6) mounted on the top surface of printed circuit board330and the remaining four output contacts332(seeFIG. 7) mounted on the bottom surface of printed circuit board330. Each output contact332may be implemented, for example, as an insulation piercing contact332that includes a pair of sharpened triangular cutting surfaces. The insulation piercing contacts332are arranged in pairs, with each pair corresponding to one of the twisted differential pairs of conductors in the communications cable that is connected to plug300. It will be appreciated that other types of output contacts such as insulation displacement contacts (IDCs) could be used.

The top and bottom surfaces of the termination manager320each have a plurality of generally rounded channels324molded therein. Each channel324guides a respective one of the eight insulated conductors of the communications cable so as to be in proper alignment for making electrical connection to a respective one of the insulation piercing contacts332. Each of the insulation piercing contacts332extends though a respective opening326in one of the channels324. When an insulated conductor of the cable is pressed against its respective insulation piercing contact332, the sharpened triangular cutting surfaces pierce the insulation to make physical and electrical contact with the conductor. Each insulation piercing contact332includes a base post (not shown) that is mounted in, for example, metal plated apertures in the printed circuit board330.

FIG. 8is a schematic plan view of the printed circuit board330. The printed circuit board330is a two layer printed circuit board that includes conductive traces on its top side and its bottom side. Dotted lines are used to illustrate traces/circuits that are on the bottom side, and solid lines are used to illustrate traces/circuits that are on the top side. It will be appreciated thatFIG. 8is a schematic diagram and is not intended to illustrate the actual placement of the conductive paths, circuit elements, integrated circuit chips and the like that are included in or on printed circuit board330. In practice, such placement would consider a wide variety of factors such as the impact on insertion loss, return loss, crosstalk, current-carrying capabilities of traces and layers, heat dissipation and various other factors. It will also be appreciated that each of the conductive paths shown inFIG. 8may, for example, be implemented as one or more conductive traces on one or more layers of the printed circuit board330and, as necessary, metal-filled holes or other layer-transferring techniques may be used to electrically connect conductive traces that reside on different layers. Likewise, the plate capacitors shown inFIG. 8that are used to inject offending crosstalk (see discussion below) may, for example, alternatively be implemented using inter-digitated finger capacitors or replaced (or augmented) by other capacitive and/or inductive coupling structures that are known in the art. Thus, whileFIG. 8is a schematic diagram that illustrates a functional layout of the printed circuit board330, it will be appreciated that an actual implementation may look quite different fromFIG. 8.

As shown inFIG. 8, the printed circuit board330includes a first set of eight metal-plated apertures334. InFIG. 8, only three of the metal-plated apertures334are labeled with reference numerals (namely metal-plated apertures334-1,334-2and334-8) in order to simplify the drawing. It will be appreciated that the unlabeled metal-plated apertures that are disposed between apertures334-2and334-8are apertures334-3through334-7. Applicants have used the same convention for labeling the sets of metal-plated apertures336and338and for labeling the sets of conductive traces350,352,356and358inFIG. 8(these elements are discussed below) in order to improve the readability ofFIG. 8.

Each of the metal-plated apertures334-1through334-8holds the end of a respective one of the plug blades3404through340-8. The printed circuit board330also includes a set of eight metal-plated apertures336that hold the other ends of the respective plug blades340. The printed circuit board330further includes an additional set of eight metal-plated apertures338that each hold the base post of a respective one of the insulation piercing contacts332.

As shown inFIG. 8, a first low pass filter integrated circuit chip360is mounted on the top of printed circuit board330. The first low pass filter integrated circuit chip360may include eight input pins that are electrically connected to eight output pins through eight respective low pass filters that are implemented within the chip360. A high pass filter integrated circuit chip362is mounted to extend downwardly from the bottom of printed circuit board330. The high pass filter integrated circuit chip362may include eight input pins that are electrically connected to eight output pins through eight respective high pass filters that are implemented within the chip362. A set of eight conductive paths350are provided, each of which electrically connects one of the eight metal-plated apertures336to a respective input pin on the low pass filter integrated circuit chip360. A set of eight conductive paths352are provided, each of which electrically connects one of the eight metal-plated apertures336to a respective input pin on the high pass filter integrated circuit chip362. Each metal-plated aperture336thus acts as signal path splitter as each signal that is input on one of the plug blades340is split onto the two conductive paths350,352that are connected to the metal-plated aperture336that holds the back end of the plug blade340.

A set of eight conductive paths354are provided which, consistent with the labeling convention discussed above, are individually labeled354-1through354-8inFIG. 8. As shown inFIG. 8, each of the conductive paths354electrically connects one of the eight output pins on the low pass filter integrated circuit chip360to a respective one of the eight input pins on the low pass filter integrated circuit chip364. As is further shown inFIG. 8, a plurality of capacitors370,372,374,376are provided. Each of the capacitors370,372,374,376is implemented as a plate capacitor that has a first plate on the top layer of the printed circuit board330and a second plate on the bottom layer of the printed circuit board330. The first plate of capacitor370is electrically connected to conductive path354-2, and the second plate of capacitor370is electrically connected to conductive path354-3through an electrically conductive via366. The first plate of capacitor372is electrically connected to conductive path354-3, and the second plate of capacitor372is electrically connected to conductive path354-4through another electrically conductive via366. The first plate of capacitor374is electrically connected to conductive path354-5, and the second plate of capacitor374is electrically connected to conductive path354-6through another electrically conductive via366. The first plate of capacitor376is electrically connected to conductive path354-6, and the second plate of capacitor376is electrically connected to conductive path354-7through yet another electrically conductive via366. The operation of capacitors370,372,374,376is explained below.

Eight conductive paths356are also provided on printed circuit board330, each of which electrically connects one of the output pins on the low pass filter integrated circuit chip364to a respective one of the eight metal-plated apertures338. Finally, eight conductive paths358are provided, each of which electrically connects one of the output pins on the high pass filter integrated circuit chip362to a respective one of the eight metal-plated apertures338.

As the above discussion ofFIG. 8makes clear, two separate conductive paths380,382extend between each metal-plated aperture336and its corresponding metal-plated aperture338. For example, with respect to metal plated aperture336-1, the conductive path350-1, the first low pass filter integrated circuit chip360, the conductive path354-1, the second low pass filter integrated circuit chip364and the conductive path356-1together comprise a first conductive path380-1that connects aperture336-1to aperture338-1. This first conductive path380-1is a “low frequency” conductive path as the low pass filters in integrated circuit chips360and364will only allow low frequency signals to traverse conductive path380-1. The conductive path352-1, the high pass filter integrated circuit chip362, and the conductive path358-1together comprise a second conductive path382-1that also connects aperture336-1to aperture338-1. This second conductive path382-1is a “high frequency” conductive path as the high pass filter in integrated circuit chip362will only allow high frequency signals to traverse conductive path380-2.

In the embodiment ofFIGS. 5-8, the low pass filters in the low pass filter integrated circuit chip360and364are configured to pass signals with frequencies below about 500 MHZ while blocking signals with frequencies above about 500 MHz. The high pass filters in the high pass filter integrated circuit chip362are configured to pass signals with frequencies above about 500 MHZ while blocking signals with frequencies below about 500 MHz. It will be appreciated that each filter will have a transition region where the filter response will transition from passing signals to attenuating signals. The size of this transition region (e.g., in MHz) is dependent on the filter design. It will likewise be appreciated that the 500 MHz cut-off frequency for the low pass filters and the high pass filters discussed above is exemplary in nature, and that any appropriate cut-off frequencies may be selected for the filters depending upon the design objectives.

Currently, various industry standards that apply to, for example, RJ-45 communications plugs and communication jacks, specify various performance characteristics for the plugs and the jacks and the differential pairs thereof. By way of example, the TIA/EIA-568C.2 “Category 6A” standard specifies ranges for near-end crosstalk that must be present between the differential pairs of an RJ-45 communications plug. As noted above, the communications plug300may be designed to comply with these performance specifications while also providing enhanced channel capacity at higher frequencies, as will be apparent in light of the following description of the operation of the plug300.

The plug blades on most conventional plugs include metal plate portions that are aligned in a row. The metal plate portion of each such plug blade may capacitively and inductively couple with the metal plate portions of one or more adjacent plug blades. The metal plate portions may be designed so that the amount of coupling between the differential pairs of the plug will fall within the ranges specified within one or more of the industry standards. In contrast to these conventional plugs, communications plug300uses skeletal plug blades340that generate reduced amounts of offending crosstalk between the plug blades of adjacent differential pairs. In order to increase the amount of offending crosstalk to bring the plug300into compliance with these industry standards, the above-described capacitors370,372,374,376are provided that inject offending crosstalk between the differential pairs of plug300. In particular, capacitor370increases the amount of offending crosstalk between pairs2and3, the capacitors372and374increase the amount of offending crosstalk between pairs1and3, and the capacitor376increases the amount of offending crosstalk between pairs3and4. While a total of four capacitors are shown inFIG. 8, it will be appreciated that additional capacitors (or other crosstalk generating structures), which are not shown inFIG. 8, may be provided as necessary to increase the amount of offending crosstalk between differential pairs that do not have adjacent conductors in the plug-jack mating region such as, for example, a capacitor that generates offending crosstalk between pairs1and2(e.g., a capacitor between conductors2and4) and a capacitor that generates offending crosstalk between pairs1and4(e.g., a capacitor between conductors5and7).

Notably, the capacitors370,372,374,376are located on the low frequency conductive paths380. As such, the additional offending crosstalk that is generated by these capacitors will only be injected into low frequency signals (which, in the example ofFIGS. 5-8, are signals at frequencies less than 500 MHz). As various industry standards may only specify offending crosstalk levels up to a certain cut-off frequency (e.g., 500 MHz), the plug300may be designed to inject appropriate amounts of offending crosstalk onto all signals that are at frequencies which fall within the industry standards, thereby providing an industry-standards compliant plug. Moreover, since the plug blades340are designed to generate very low levels of offending crosstalk, the amount of crosstalk that will occur between high frequency signals that pass through the plug300may be very low as the high frequency conductive paths382do not include capacitors for injecting offending crosstalk. These reduced offending crosstalk levels may advantageously facilitate increasing channel capacity at frequencies higher than the frequencies specified in the relevant industry standards. Consequently, communications plug300may be designed to comply with industry standards such as the Category 6A standard while simultaneously being designed to support higher data rate communications using frequencies that are above the frequencies specified in the industry standard.

Operation of the communications plug300will now be explained in more detail. Referring first toFIG. 5, a differential information signal may enter the plug on the insulation piercing contacts that connect to, for example, the conductors of pair2of a cable (not shown) that is attached to plug300. Referring toFIG. 8, this differential information signal is coupled through the insulation piercing contacts to the metal-plated apertures338-1and338-2, with the first component of the differential information signal passing through aperture338-1and the second component passing through aperture338-2. At metal-plated aperture338-1, the first component of the differential information signal is passed to the second low pass, filter integrated circuit chip364via the conductive path356-1and is also passed to the high pass filter integrated circuit chip362via the conductive path358-1. At metal-plated aperture338-2, the second component of the differential information signal is passed to the second low pass filter integrated circuit chip364via the conductive path356-2and is also passed to the high pass filter integrated circuit chip362via the conductive path358-2.

If the differential information signal is at a frequency of less than 500 MHz, then first and second low pass filters that are included in the second low pass filter integrated circuit chip364allow the two components of the differential information signal to pass through the chip364where they are then output onto the conductive paths354-1and354-2. The conductive paths354-1and354-2then pass the respective components of the differential information signal to the first low pass filter integrated circuit chip360, where it passes through the corresponding low pass filters therein and is output to the corresponding conductive paths350-1and350-2. The conductive paths350-1and350-2carry the respective components of the differential information signal to respective metal-plated apertures336-1and336-2so that the two components of the differential information signal are passed to the plug blades340-1and340-2. Thus, the differential information signal will pass through plug300on the low frequency conductive paths380-1and380-2that are shown inFIG. 8. A portion of the signal on conductive path354-2is also capacitively coupled to conductive path354-3via the capacitor370in order to increase the level of offending crosstalk between pairs2and3in communications plug300for signals at frequencies below 500 MHz to a sufficient level to comply with the relevant industry standards.

In the above example, the differential information signal has a frequency of less than 500 MHz. As such, the portions of the differential information signal that are passed to the high pass filter integrated circuit chip364via the conductive paths358-1and358-2are substantially attenuated by the high pass filters therein, and hence only a very small portion of the differential information signal (i.e., a portion that has been attenuated by 30 or 40 dB) passes through the high pass filter integrated circuit chip362onto the conductive paths352-1and352-2(i.e., very little signal energy is passed through plug300on the high frequency conductive paths382-1and382-2). These small portions of the differential information signal that are passed on the high frequency conductive paths382-1and382-2are then recombined at the metal-plated apertures336-1and336-2with the portions of the differential information signal that pass through the plug300on the low frequency conductive path380-1and380-2in the manner described above. Thus, the net effect is that almost all of the signal energy of a differential information signal having a frequency of less than 500 MHz will flow through the communications plug300on two of the low frequency paths380, where one (or more) of the capacitors370,372,374,376that are on these low frequency paths380inject offending crosstalk between the pairs. The amount of offending crosstalk injected by capacitors370,372,374,376may be set so that the communications plug300will, have crosstalk levels that fall within the ranges specified in, for example, the Category 6A standard for signals at frequencies of less than 500 MHz.

If the differential information signal that enters the printed circuit board330of plug300at, for example, metal-plated apertures338-1and338-2, is at a frequency of greater than 500 MHz, then the low pass filters in the second low pass filter integrated circuit chip364substantially attenuate the two components of the differential information signal that are on the conductive paths356-1and356-2such that only a very small portion of the differential information signal (e.g., the differential signal may be reduced by 30-40 dB) is allowed onto the low frequency conductive paths380-1and380-2. However, the portions of the differential information signal that are passed from the metal-plated apertures338-1and338-2to the high pass filter integrated circuit chip362via conductive paths358-1and358-2pass through the high pass filters substantially unattenuated and are output onto conductive paths352-1and352-2where these signals are passed to the plug blades340-1and340-2that are mounted in metal-plated apertures336-1and336-2. Thus, as shown by the above example, for differential information signals having frequencies above 500 MHz, almost all of the signal energy will pass through the plug300on the corresponding high frequency conductive paths382, and hence the capacitors370,372,374,376(which are only included on the low frequency conductive paths380) will generate essentially no additional offending crosstalk for signals at frequencies exceeding 500 MHz. Thus, for signals that exceed 500 MHz, the communications plug300comprises a very low crosstalk plug (since the crosstalk between the plug blades340may be far lower than the crosstalk generated in conventional plugs). This reduction in the crosstalk generated in the plug300may allow the plug300to support higher data rates at frequencies above 500 MHz.

In some embodiments, the first low pass filter integrated circuit chip360may be located very close to the metal-plated apertures336, and the capacitors370,372,374,376may connect to the conductive paths354at or very close to the output pins of the first low pass filter integrated circuit chip360. Such an arrangement may advantageously inject the offending crosstalk close in distance and time to the point where each plug blade340mates with a corresponding contact of a mating communications jack. Reducing the amount of delay between the point where the offending crosstalk is injected and the compensation circuit in the mating jack that is designed to compensate for this offending crosstalk may result in more complete crosstalk cancellation.

As shown above, pursuant to embodiments of the present invention, communications connectors are provided that include two or more electrically parallel conductive paths between each input contact and its corresponding output contact. Each of these paths may be configured to pass signals in different (although possibly overlapping) frequency ranges. Appropriate signal conditioning circuitry may be provided along each of these parallel paths. For example, with the communications plug300ofFIGS. 5-8, capacitors370,372,374,376are provided that inject offending crosstalk on the low frequency conductive paths380so that the plug300will be an industry standards compliant plug. No signal conditioning is provided on the high frequency conductive paths382, although these communication paths do benefit from the provision of the low crosstalk plug blades340which allow the plug300to exhibit lower than normal offending crosstalk levels at frequencies above 500 MHz while still operating as an industry standards compliant plug at frequencies below 500 MHz. Thus, the provision of electrically parallel low and high frequency conductive paths380,382allows the plug300to exhibit high performance levels over a broader range of frequencies.

It will be appreciated that the communications plug300is exemplary in nature, and that various modifications may be made thereto in actual implementations. By way of example, the plug300includes four capacitors370,372,374,376that are used to inject offending crosstalk between pairs2and3, pairs1and3and pairs3and4. In other embodiments, more or fewer capacitors could be provided for injecting offending crosstalk, and offending crosstalk could be injected between additional and/or between different pair combinations. It will likewise be appreciated that inductive coupling structures such as closely spaced conductive traces could additionally or alternatively be provided and/or different capacitor designs (e.g., lumped elements, interdigitated finger capacitors, etc.) could be used to inject the offending crosstalk. As another example, the low pass filters and/or high pass filters may be implemented on less than all pairs of conductors.

As another example, the communications plug300only performs signal conditioning on the low frequency conductive paths380(namely, the injection of offending crosstalk between selected differential pairs), and does not perform any signal conditioning on the high frequency conductive paths382. In other embodiments, signal conditioning may alternatively or additionally be performed on the high frequency conductive paths382. In such embodiments, the high frequency conductive paths may include first and second high pass filter integrated circuit chips (as opposed to the single chip362provided in plug300) in order to isolate the effects of this signal conditioning from the low frequency conductive paths.

Another modification that could be made to the communications plug300is the provision of more than two electrically parallel paths380,382. For example, in further embodiments, three or more electrically parallel paths could be provided between the plug blades340and the output contacts332, with each path designed to pass signals at certain frequencies while blocking signals at other frequencies.

It will also be appreciated that in some embodiments one of the first and second low pass filter integrated circuit chips360,364could be omitted. For example, one of the first and second low pass filter integrated circuit chips360,364might be omitted in an alternate plug design that replaced the capacitors370,372,374and376with inductive coupling structures. It will also be appreciated that the low pass and high pass filters may be implemented at least in part using capacitors and/or inductors that are provided within plug300for other reasons such as for crosstalk compensation, return loss control, etc.

It will further be appreciated in light of the present disclosure that improved performance may be achieved by providing plug and jack communications connectors that both have multiple electrically parallel conductive paths between their input and output contacts. By way of example, the communications plug300ofFIGS. 5-8exhibits low offending crosstalk levels for high frequency signals, but higher offending crosstalk levels for low frequency signals (due to the provision of the capacitors370,372,374,376that inject offending crosstalk). Thus, if plug300is mated with a jack that includes a single crosstalk compensation circuit, it may be difficult to cancel high levels of crosstalk across all frequency ranges due to the different amounts of crosstalk injected in the plug300on the low and high frequency conductive paths380,382. Consequently, pursuant to further embodiments of the present invention communications jacks are provided that likewise have low and high frequency conductive paths with different signal conditioning thereon that may be designed to complement the signal conditioning provided on the low and high frequency conductive paths380,382of a mating communications plug such as plug300.

FIGS. 9 and 10illustrate a communications jack400according to embodiments of the present invention that is designed to work in conjunction with communications plug300to provide improved performance over a wide range of frequencies. In particular,FIG. 9is a perspective view of the communications jack400, andFIG. 10is a schematic plan view of a flexible printed circuit board of the communications jack400.

As shown inFIG. 9, the jack400includes a three piece housing400that includes a jack frame412having a plug aperture414for receiving a mating plug, a cover416and a terminal housing418. The housing components412,416,418may be conventionally formed and not need be described in detail herein.

The jack400further includes a communications insert420. The communications insert420comprises a substrate422that has a spring424, a flexible printed circuit board430and a plurality of output terminals470mounted thereon. The communications insert420is received within an opening in the rear of the jack frame412. The bottom of the communications insert420is protected by the cover416, and the top of the communications insert420is covered and protected by the terminal housing418.

The spring424and the flexible printed circuit board430are both mounted on a top surface of the substrate422. The printed circuit board430may include a plurality of apertures431. The spring424may include a plurality of downwardly-extending extensions that extend through the apertures431and are used to mount the spring424in the substrate422. The spring424may comprise, for example, a flexible cantilevered member that extends upwardly at an angle from the substrate422through the openings431in the flexible printed circuit board430. A front portion432of the flexible printed circuit board430is bent back over the substrate422so as to expose the bottom surface436of the front portion432of the flexible printed circuit board430. The top surface434of the front portion432of the flexible printed circuit board430may rest against the spring424. The very front portion of the flexible printed circuit board430may be mounted to the distal end of the spring424by any conventional mounting mechanism (e.g., a screw, an adhesive, etc.).

Eight rectangular contact pads441-448are provided on the bottom surface436of the front portion432of flexible printed circuit board430. The eight contact pads441-448are positioned within the plug aperture414so that they will make physical and electrical contact with the respective blades of a mating communications plug that is received within the plug aperture414. As the front portion of the flexible printed circuit board430is attached to the spring424, the spring424may ensure that each contact pad engages its respective mating plug blade with a sufficient contact force to provide a good electrical connection therebetween.

The contact pads441-448are arranged in pairs defined by TIA 568B (seeFIG. 2and discussion thereof above). The output terminals450are mounted in the substrate422through respective metal-plated apertures in the flexible printed circuit board430. Conductive traces (not shown) are provided on the flexible printed circuit board430that connect each contact pad441-448to a respective one of the metal-plated apertures that hold the output terminals450, thereby electrically connecting each contact pad441-448to its respective output terminal450. In the depicted embodiment, each output terminal450is implemented as an IDC. As is well known to those of skill in the art, an IDC is a type of wire connection terminal that may be used to make mechanical and electrical connection to an insulated wire conductor. Terminal cover418includes a plurality of pillars that cover and protect the IDCs450. Adjacent pillars are separated by wire channels. The slot of each of the IDCs450is aligned with a respective one of the wire channels. Each wire channel is configured to receive a conductor of a communications cable so that the conductor may be inserted into the slot in a respective one of the IDCs450.

As noted above, the jack400may be designed to have multiple electrically parallel low and high frequency conductive paths that complement the corresponding low and high frequency conductive paths of the communications plug300. In the jack400, these electrically parallel conductive paths380,382are implemented on the flexible printed circuit board430, as shown inFIG. 10.

As shown inFIG. 10, a plurality of conductive paths460are connected to the contact pads441-448. Various crosstalk compensation circuit elements462may be provided along these conductive paths460to compensate for crosstalk that arises in a mating plug and between the input contacts441-448. While the crosstalk compensation circuit elements462are illustrated for simplicity using a single block inFIG. 10, it will be appreciated that the crosstalk compensation circuit elements462will typically comprise a plurality of individual crosstalk compensation circuits, at least some of which may comprise multi-stage crosstalk compensation circuits that includes multiple time-delayed compensation components.

As is further shown inFIG. 10, each conductive path460is split into first and second conductive paths464,466. Each of the conductive paths464is part of a plurality of low frequency conductive paths480, while each of the conductive paths466is part of a plurality of high frequency conductive paths482. As shown inFIG. 10, a first bank of low pass filters468and a second bank of low pass filters470are provided on the low frequency conductive paths480so that only low frequency signals may traverse the jack400on the low frequency conductive paths480. A bank of high pass filters472is provided on the high frequency conductive paths482so that only high frequency signals may traverse the jack400on the high frequency conductive paths482. The banks of low pass and high filters468,470,472may be implemented using low and high pass filter integrated circuit chips that are identical to the low pass and high pass filter integrated circuit chips discussed above with respect to communications plug300, and hence further description thereof will be omitted. As is further shown inFIG. 10, each conductive path464is combined with its corresponding (parallel) conductive path468at the outputs of the low pass filters470and the high pass filters472. Conductive traces474connect each combined trace to its corresponding IDC aperture that hold the IDCs450.

As is further shown inFIG. 10, an additional crosstalk compensation circuit476is provided along the low frequency conductive paths480. The crosstalk compensation circuit476may provide additional crosstalk compensation to compensate for the additional offending crosstalk that is added by capacitors370,372,374,376in the communications plug300. The crosstalk compensation circuit476may comprise a plurality of single stage and/or multi-stage crosstalk compensation circuits that are designed to compensate for the offending crosstalk that is injected by the capacitors370,372,374,376, and may include capacitive components and/or inductive components. As discussed above, the capacitors370,372,374,376only inject additional offending crosstalk on low frequency signals, and the crosstalk compensation circuit476is likewise designed to only inject compensating crosstalk with respect to low frequency signals as the circuit476is only implemented on the low frequency conductive paths480. The crosstalk compensation circuit476thus acts to provide additional crosstalk compensation for low frequency signals that compensates for the additional offending crosstalk added by capacitors370,372,374,376without providing any additional crosstalk compensation for high frequency signals. Consequently, the jack400may provide the appropriate amount of crosstalk compensation for both low and high frequency signals.

It will be appreciated that many modifications may be made to the communications jack400without departing from the scope of the present invention. By way of example, in further embodiments, additional signal conditioning may be performed along the high frequency conductive paths482. In such embodiments, the high frequency conductive paths482may include first and second banks of high pass filters with the signal conditioning circuitry located therebetween in order to isolate this signal conditioning circuitry from the low frequency conductive paths. Another modification that could be made to the communications jack400is the provision of more than two sets of parallel paths480,482. As yet another example, the jack400could be modified to only perform signal conditioning and/or parallel paths on some of the conductive paths through the jack.

It will also be appreciated that additional and/or different types of signal conditioning could be performed on the low and high frequency conductive paths480,482. By way of example, in further embodiments, a first multistage crosstalk compensation circuit could be provided on the low frequency conductive paths480and a second multistage crosstalk compensation circuit could be provided on the high frequency conductive paths482. These multi-stage crosstalk compensation circuits would be in addition to the crosstalk compensation circuit462, and may be designed to provide some of the crosstalk compensation that otherwise would be injected by crosstalk compensation circuit462. The multistage crosstalk compensation circuits that are added to the low and high frequency conductive paths480,482could be designed to optimize performance over different frequency ranges to enhance the crosstalk cancellation performance of the jack400over a wider frequency range. Thus, it will be appreciated that the communications jack400is exemplary in nature and is described to illustrate the concept of using parallel conductive paths, at least one of which is limited to a specific frequency band or bands, in order to provide enhanced performance.

It will be appreciated that according to further embodiments of the present invention plugs and jacks may be provided that do not include any high pass filters (or band pass filters) along the conductive paths that are implemented in parallel to the low frequency conductive paths. In such embodiments, the connector may include a plurality of conductive paths that pass signals at all frequencies (“all frequency conductive paths”) that are in parallel to respective ones of a plurality of low frequency conductive paths. In these connectors, low frequency signals (e.g., signals having frequencies of less than 500 MHz) may traverse both sets of parallel conductive paths through the connector, while higher frequency signals will only traverse the all frequency conductive paths, as the low pass filters block such higher frequency signals from the low frequency conductive paths. The signal conditioning circuits on the low frequency conductive paths (e.g., capacitors370,372,374,376on plug300or circuit476on jack400) may be appropriately modified to inject the appropriate amount of offending or compensating crosstalk.

As discussed above, in some embodiments, a first plurality of conductive paths may be designed to pass signals having a frequency lower than a selected cutoff frequency, while a second plurality of conductive paths may be designed to pass signals having a frequency higher than the selected cutoff frequency. In such embodiments, low pass filters may be provided on the first plurality of conductive paths and high pass filters may be provided on the second plurality of conductive paths. These low and high pass filters may be designed to have sharp transition regions between the pass band and blocking band of the filter response, and the transition regions of the low pass filters and high pass filters may cross each other.FIG. 11Aschematically illustrates exemplary frequency responses for such low pass and high pass filters. As can be seen fromFIG. 11A, both the low pass and high pass filters transition from the pass band to the blocking band in the space of less than bout 10 MHz, with the low and high pass filter responses crossing each other at about 500 MHz.

In other embodiments, the low pass filters and high pass (or band pass) filters may be designed so that their transition regions do not cross.FIG. 11Bschematically illustrates exemplary frequency responses for a connector design that includes low pass filters and high pass filters that have a “null” response therebetween. In particular, as shown inFIG. 11B, the low pass filter has a response that passes signals of about 500 MHz and below, while the high pass filter has a response that passes signals of about 600 MHz and above. These responses trail off more slowly, and there is a distinct null where signals in the range of about 525 MHz to 575 MHz will not pass on either of the first and second sets of conductive paths. In connectors that utilize the approach illustrated inFIG. 11B, the devices that transmit signals through the connector may be designed so that they do not transmit signals at the frequencies associated with the null.

As shown inFIGS. 11A and 11B, the low pass filters and high pass filters used in the connectors according to embodiments of the present invention will not exhibit infinite isolation. Instead, it is anticipated that typical filter designs will attenuate the signals by 20 dB or more in the blocking band of the filter response. As such, it will be appreciated that even when a connector according to embodiments of the present invention is designed to have signals input thereto travel through the connector on only a first of two parallel paths, in reality a small portion of the signal will flow on the second parallel path and be recombined with the signal that travels on the first parallel path at the opposite end of the connector.

In some embodiments, the connectors according to embodiments of the present invention may use multi-layer printed circuit boards that include conductive traces on their top and bottom surfaces as well as additional conductive surfaces on interior layers thereof. In such embodiments, some or all of the high frequency conductive traces (or portions thereof) may be implemented on interior layers of the multi-layer printed circuit boards. Typically, the current carrying traces on RJ-45 plug and jack printed wiring boards are disposed on either the top or bottom layers of the printed circuit board so that these traces can handle specified surge current levels without destroying the printed circuit board and/or without catching fire. However, as the surge currents are DC currents, these currents will not flow to the high frequency conductive paths, and hence the high frequency conductive paths may be implemented on interior layers of the printed circuit board. The traces for the high frequency paths may also be significantly smaller than the printed circuit board traces included in conventional RJ-45 plugs and jacks such as, for example, printed circuit board traces having widths of 3.0 mil or even less.

As set forth above, embodiments of the present invention provide improved communications plugs and jacks that implement different levels of electrical performance (e.g., crosstalk) for different frequency bands. For example, in some embodiments, RJ-45 plugs and jacks are provided that may provide better than 10 G performance by using a first signal channel for signals below 500 MHz and a second, parallel signal channel for signals above 500 MHz that are sufficiently isolated from each other via, for example, a crossover network with a crossover frequency of 500 MHz. The high frequency channel may, for example, be optimized for maximizing channel capacity, with reduced levels of NEXT, FEXT, return loss, insertion loss and conversion loss for signals having frequencies between 500 MHz and, for example, 2 GHz. The low frequency channel may be designed to have the necessary levels of NEXT and FEXT, insertion loss, return loss and conversion loss to be compliant with the relevant industry standards such as, for example, the Category 6A standard for signals in the frequency range of 1 MHz to 500 MHz. As a result, industry standards' compliant plugs and jacks can be provided that may exhibit better than 10 G performance. In some embodiments, the high frequency channel may be replaced with a channel that passes all frequencies.

While the communications plug300uses one exemplary type of low-crosstalk plug blade, it will be appreciated that numerous other low-crosstalk plug blade designs could be used. For example, in other embodiments, the plug may be designed so that the current runs in opposite directions through adjacent plug blades that are part of different differential pairs. This could be accomplished, for example, by connecting the traces350and352to metal-plated aperture334instead of to metal-plated aperture336for plug blade340-1,340-2,340-4and340-5. Since the currents flow through different parts of adjacent plug blades340that are part of different differential pairs (i.e., either the front portion or the rear portion) and flow in opposite directions on such adjacent plug blades340; there is less inductive coupling between adjacent plug blades that are part of different differential pairs. As another example, the conductive paths352may connect to the metal-plated apertures336while the conductive paths350connect to the metal-plated apertures334which may facilitate further, controlling impedance and/or crosstalk. As yet another example, the plug blades340could be replaced with contact pads that are disposed on the top and front surface of the printed circuit board330that are configured to physically contact the contacts of a mating jack. The use of contact pads as plug blades can further decrease the capacitive and/or inductive coupling between adjacent plug blades.

While embodiments of the present invention have primarily been discussed herein with respect to communications plugs and jacks that include eight conductive paths that are arranged as four differential pairs of conductive paths, it will be appreciated that the concepts described herein are equally applicable to connectors that include other numbers of differential pairs. It will also be appreciated that communications cables and connectors may sometimes include additional conductive paths that are used for other purposes such as, for example, providing intelligent patching capabilities. The concepts described herein are equally applicable for use with such communications cables and connectors, and the addition of one or more conductive paths for providing such intelligent patching capabilities or other functionality does not take such cables and connectors outside of the scope of the present invention or the claims appended hereto.

While the present invention has been described above primarily with reference to the accompanying drawings, it will be appreciated that the invention is not limited to the illustrated embodiments; rather, these embodiments are intended to fully and completely disclose the invention to those skilled in this art. In the drawings, like numbers refer to like elements throughout. Thicknesses and dimensions of some components may be exaggerated for clarity.

Well-known functions or constructions may not be described in detail for brevity and/or clarity. As used herein the expression “and/or” includes any and all combinations of one or more of the associated listed items.

Herein, the terms “attached”, “connected”, “interconnected”, “contacting”, “mounted” and the like can mean either direct or indirect attachment or contact between elements, unless stated otherwise.

Note that in the claims appended hereto, references to “each” of a plurality of objects (e.g., plug blades) refers to each of the objects that are positively recited in the claim. Thus, if, for example, a claim positively recites first and second of such objects and states that “each” of these objects has a certain feature, the reference to “each” refers to the first and second objects recited in the claim, and the addition of a third object that does not include the feature is still encompassed within the scope of the claim. Likewise, if the claim recites a plurality of objects and states that “each” of these objects has a certain feature, the reference to “each” refers to at least two of the objects, and the addition of a third object that does not include the feature is still encompassed within the scope of the claim.