Patent Grant
9112320
The present invention relates generally to communications connectors and, more particularly, to communications connectors that may exhibit improved performance over a wide frequency range.
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.
The communications jack 20 includes a back-end wire connection assembly 24 that receives and holds insulated conductors from a cable 26. As shown in
In the above-described communications system, the information signals that are transmitted between the computer 10 and the network device 30 are 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 the information signal.
Various industry standards, such as the ANSI/TIA-568-C.2 standard approved Aug. 11, 2009 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. By way of example, the ANSI/TIA-568-C.2 standard is designed to ensure that plugs, jacks and cable segments that comply with the standard will provide certain minimum levels of performance for signals transmitted at frequencies of up to 500 MHz. Most of these industry standards specify that each jack, plug and cable segment in a communications system must include a total of eight conductors 1-8 that 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 jackwire contacts of the jack (referred to herein as the “plug jack mating region”), the eight conductors are generally aligned in a row. As shown in
Unfortunately, the industry-standardized configuration for the plug-jack mating region that is shown in
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 the industry-standardized plug jack interface. In order to achieve high levels of crosstalk cancellation, the industry standards specify pre-defined ranges for the crosstalk that is injected between the four differential pairs in each communications plug, which allows each manufacturer to design the crosstalk compensation circuits in their communications jacks to cancel out these pre-defined 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 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.
Pursuant to embodiments of the present invention, communications connectors are provided that include a plurality of input contacts that are arranged as differential pairs of input contacts, a plurality of first output contacts that are electrically connected to respective ones of the plurality of input contacts, and a first pair of second output contacts that are electrically connected by a pair of conductive paths to one of the differential pairs of input contacts. The first output contacts are configured to physically contact respective ones of a plurality of first contacts of a second communications connector. Moreover, each contact of the first pair of second output contacts is electrically in parallel to a respective one of the first output contacts when the communications connector is mated with the second communications connector.
Each contact of the first pair of second output contacts may be configured to physically or reactively couple with a respective contact of a pair of second contacts of the second communications connector. In some embodiments, a plurality of low frequency conductive paths may connect the input contacts to respective ones of the first output contacts, and the pair of conductive paths may comprise a pair of high frequency conductive paths. The communications connectors may also include a second pair of second output contacts, and the minimum distance between the first and second pairs of second output contacts may be at least five times the minimum distance between the contacts of the first pair of second output contacts.
In some embodiments, the input contacts may receive the respective conductors of a communications cable, and the first output contacts may be plug blades or jackwire contacts. The connector may be is an RJ-45 plug and the second connector may be an RJ-45 jack. The first output contacts may be part of a first set of communications paths through the mated combination of the communications connector and the second communications connector, and the first pair of second output contacts may be part of a second set of communications paths through the mated combination, and the first set of communications paths may be configured to carry low frequency signals and the second set of communications paths may be configured to carry high frequency signals. A low pass filter may be coupled between a first of the input contacts and a first of the first output contacts. A band pass or high pass filter may be coupled between a first of the input contacts and one of the contacts of the first pair of second output contacts.
Pursuant to embodiments of the present invention, communications connectors are provided that include a plurality of input contacts that are arranged as differential pairs of input contacts, a plurality of first output contacts, a plurality of first conductive paths that electrically connect each input contact to a respective one of the first output contacts, a plurality of second output contacts, and a plurality of second conductive paths that electrically connect each input contact to a respective one of the second output contacts. Each of the second conductive paths is routed in parallel to a respective one of the first conductive paths when the communications connector is mated with a second communications connector.
In some embodiments, the first conductive paths may be low frequency conductive paths that are configured to pass low frequency signals and substantially attenuate higher frequency signals. The second conductive paths may be high frequency conductive paths that are configured to pass high frequency signals and substantially attenuate lower frequency signals. The low frequency conductive paths may be configured, for example, to pass signals having frequencies between at least 1 MHz and 500 MHz, and the high frequency conductive paths may be configured, for example, to pass signals having frequencies within at least part of the frequency band between 500 MHz and 3 GHz. The first output contacts may be configured to physically mate with respective ones of a plurality of first contacts of the second communications connector, and the second output contacts may be configured to reactively couple with respective ones of a plurality of second contacts of the second communications connector.
Pursuant to embodiments of the present invention, RJ-45 jacks are provided that include a jack housing having a plug aperture that is configured to receive an RJ-45 plug, first through eighth output contacts that are configured to receive the conductors of a communications cable, first through eighth input contacts that are electrically connected to respective ones of the first through eighth output contacts via first through eighth conductive paths, the first through eighth input contacts configured to mate with first through eighth contacts of the RJ-45 plug when the RJ-45 plug is received within the plug aperture, a ninth input contact that is electrically connected to the first output contact, and a tenth input contact that is electrically connected to the second output contact. The ninth and tenth input contacts are configured to electrically communicate with ninth and tenth contacts of the RJ-45 plug when the RJ-45 plug is received within the plug aperture.
In some embodiments, wherein the ninth and tenth input contacts may be configured to reactively couple with the respective ninth and tenth contacts of the RJ-45 plug without physically touching the respective ninth and tenth contacts of the RJ-45 plug. The jacks may also include low pass filters that are provided along a first of the first through eighth conductive paths. The jacks may also include first high pass filters or band pass filters that are provided along a conductive path between the ninth input contact and the first output contact and second high pass filters or band pass filters that are provided along a conductive path between the tenth input contact and the second output contact. The ninth and tenth input contacts may be configured to make physical contact with the respective ninth and tenth contacts of the RJ-45 plug.
Pursuant to embodiments of the present invention, communications plugs and jacks are provided that include a first set of contacts that may be used to carry, for example, low frequency signals (e.g., signals within a frequency range specified in an industry standard such as the 0-500 MHz frequency range specified in the Category 6a standard) to a mating connector and a second set of contacts that may be used to carry, for example, higher frequency signals to the same mating connector. The first set of contacts are associated with a first set of conductive paths that 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 contacts on these plugs and jacks are associated with a second set of conductive paths that 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, the first set of low frequency contacts in the plugs and jacks may be configured so that each plug contact physically contacts its respective jack contact, while the second set of high frequency contacts in the plugs and jacks may be configured so that each plug contact reactively couples to (i.e., capacitively and/or inductively) its respective jack contact. In other embodiments, the first set of low frequency contacts in the plugs and jacks may be configured so that each plug contact physically contacts its respective jack contact, and the second set of high frequency contacts in the plug may likewise be configured to physically contact the second set of high frequency contacts in the jack.
Filters may be provided in the plugs and jacks that may be used to route low frequency signals to the low frequency contacts and to route high frequency signals to the high frequency contacts. For example, low pass filters may be provided that pass signals that are below a certain frequency (e.g., 500 MHz) to the low frequency contacts while substantially attenuating signals at higher frequencies. In some embodiments, the low frequency contacts may themselves be designed to act as the low pass filters or to act as part of a low pass filter circuit. Bandpass or high pass filters may likewise be provided that pass at least some signals at frequencies exceeding 500 MHz, while substantially attenuating signals at lower frequencies. In some embodiments, the high frequency contacts may likewise be designed to act as the bandpass or high pass filters or to act as part of a bandpass or high pass filter circuit. In other embodiments, separate low pass, bandpass or high pass filters may be implemented in the plug, in the jack, or in both the jack and plug (i.e., two filters would be provided along each conductive path) instead of using contact designs that act as filters.
In some embodiments, two full sets of contacts (e.g., two sets of eight contacts for a total of sixteen contacts) may be provided on each plug and jack. In other embodiments, smaller numbers of contacts can be provided on each plug and jack (i.e., a full set of contacts for the low frequency signals and less than a full set of contacts for the high frequency signals). Less than two full sets of contacts may be used since, for example, pairs 2 and 4 in
Embodiments of the present invention will now be described with reference to the accompanying drawings, in which exemplary embodiments are shown.
As shown in
In some embodiments, the first set of conductive paths 122 may comprise a first frequency selective set of conductive paths, and the second set of conductive paths 124 may comprise a second set of frequency selective conductive paths. For example, the first frequency selective set of conductive paths 122 may be designed to pass signals at frequencies of less than about 500 MHz while substantially attenuating signals at higher frequencies, and the second frequency selective set of conductive paths 124 may be designed to pass signals at frequencies greater than about 500 MHz while substantially attenuating signals at lower frequencies. It will be appreciated that in some embodiments one of the first or second frequency selective sets of conductive paths 122, 124 may be designed to pass signals at all frequencies.
The first set of frequency selective conductive paths 122 connect to a first set of output contacts 130 of the communications plug 100. The output contacts 130 may comprise, for example, conventional plug blades, non-conventional plug blades, contact pads, etc. In some embodiments, the contacts in the first set of input contacts 130 may comply with all of the required specifications of an applicable industry standards document so that the first set of contacts 130 comprise an industry-standards compliant set of contacts. The second set of frequency selective conductive paths 124 likewise connect to a second set of output contacts 140 of the communications plug 100. The output contacts 140 may comprise, for example, conventional plug blades, non-conventional plug blades, contact pads, etc.
As is further shown in
A first set of conductive paths 165 is provided that are used to connect each contact in the first set of input contacts 160 to a splitter/combiner circuit 180, and a second set of conductive paths 175 is provided that are used to connect each contact in the second set of input contacts 170 to the splitter/combiner circuit 180. The splitter/combiner circuit 180 combines the signals present on the first and second set of conductive paths 165, 175 onto a single set of conductive paths 185. A plurality of conductive paths 185 are provided that connect the splitter/combiner circuit 180 to a plurality of output contacts 190. The output contacts 190 may comprise, for example, insulation displacement contacts (IDCs), insulation piercing contacts, pad contacts, etc.
While the discussion above focuses on signals that are passed from the plug 100 to the jack 150, it will be appreciated that signals may travel in both directions through the mated plug-jack combination 100/150, so if the direction of the signal is reversed the output contacts in
As shown in
The splitter/combiner circuit 220 splits each of the conductive paths 212 into a low frequency conductive path 222 and a high frequency conductive path 224. The splitter/combiner circuit 220 may comprise, for example, a plurality of conductive traces, each of which has another conductive trace branching off therefrom. As shown in
As shown in
Each of the low frequency conductive paths 222 connect to a respective one of a first set of output contacts 230. Each of the high frequency conductive paths 224 connect to a respective one of a second set of output contacts 240. The first set of output contacts 230 may comprise, for example, a conventional set of plug blades. The second set of output contacts 240 may comprise any appropriate contacts. Typically, the contacts in the second set of contacts 240 will be arranged to reduce or minimize crosstalk therebetween.
A low frequency signal may be transmitted on one of the differential pairs of conductors in cable 202 and then input to the connector 200 on the corresponding pair of input contacts 210. This signal is carried on two of the conductive paths 212, through the splitter/combiner circuit 220, over two of the low frequency conductive paths 222 to the corresponding pair of output contacts 230. The high pass filter circuit 228 may substantially prevent this low frequency signal from traversing the high frequency conductive paths 224. In contrast, when a high frequency signal is transmitted over one of the differential pairs of conductors in cable 202 and then input to the connector 200 on the corresponding pair of input contacts 210, this signal is carried on two of the conductive paths 212, through the splitter/combiner circuit 220, over two of the high frequency conductive paths 224 to the corresponding pair of output contacts 240. The low pass filter circuit 226 may substantially prevent this high frequency signal from traversing the low frequency conductive paths 222.
The communications plug 100 and jack 150 illustrated in
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 (or jack) for the plug (or jack) to be compliant with the standard. For example, Tables C.6 of Section C.4.10.3 and C.7 of Section C.4.10.5 of the ANSI/TIA-568-C.2 or “Category 6A” standard set 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. This may be accomplished by providing a first set low frequency of conductive paths 122 and a first set of output contacts 130 that are designed to fully comply with the applicable industry standards. However, by also providing an electrically parallel set of high frequency conductive paths 124 and a corresponding set of high frequency contacts 140, 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.
As shown in
As is also shown in
In the depicted embodiment, the printed circuit board structure 340 comprises two conventional printed circuit boards 342, 344 that are mechanically and electrically connected to each other. The first printed circuit board 342 extends farther forwardly than does the second printed circuit board 344, and the plug blades 331-338 are mounted along the top and front surfaces of the first printed circuit board 342. The second printed circuit board 344 may be permanently adjoined to the first printed circuit board 342 by any conventional technique including adhesives, ultrasonic welding, soldering, etc. Eight metal plated vias 361-368 are provided on the bottom surface of the first printed circuit board 342 (only vias 363 and 368 are visible in
The RJ-45 plug-jack interface may act, at least to an extent, as a low pass filter. This can be seen, for example, by looking at the insertion loss characteristics of conventional RJ-45 jacks, which show insertion loss goes up significantly with increasing frequency (which is a low pass filter effect). This may occur because the TIA/EIA 568 type B configuration of the contacts in the plug-jack interface region requires that the conductors of pair 3 be split and travel on either side of the conductors of pair 1. As a result of this split, the conductors of pair 3 do not act like a differential transmission line in the plug-jack interface region. Additionally, crosstalk compensation circuits between pairs 1 and pair 3 in conventional RJ-45 jacks (which typically add both capacitive and inductive crosstalk compensation in order to address both NEXT and FEXT) create an L-C combination that may have a frequency response that has some low pass filter characteristics, albeit typically not the frequency response of a high quality low pass filter.
According to some embodiments of the present invention, the natural low pass filtering effects of the standard RJ-45 plug-jack interface may be taken advantage of in order to implement one or more of the low pass filters 369. For example, in some embodiments, the low pass filter 369 may be implemented by adding self-inductance on one or both conductors of a pair in order to tune the low pass filtering effects of the interface to provide a filter response having a desired “knee” frequency. This self-inductance may be implemented, for example, using surface mount inductors, by forming self-coupling sections in a particular conductor that have the same or a similar instantaneous current direction (e.g., by routing a conductor in a spiral pattern) or by forming self coupling sections between the two conductors of a pair that have the same or a similar instantaneous current direction. In other embodiments, more complex low pass filters 369 may be used that provide an improved frequency response.
The plug blades 331-338 are configured to make mechanical and electrical contact with respective contacts of a mating communications jack. In order to comply with the applicable industry standards, the eight plug blades 331-338 may be substantially transversely aligned in side-by-side relationship. In the depicted embodiment, each of the plug blades 331-338 includes a first section that extends forwardly along a top surface of the first printed circuit board 342 (see
As shown in
A wide variety of techniques may be used to minimize the crosstalk, whether differential-to-differential or differential-to-common mode, between the contact pads 351-358. For example, the second printed circuit 344 board may be formed as a relatively large printed circuit board in order to reduce crosstalk by increasing the distance between the pairs. Additionally, the contact pads 351-358 may be arranged in a manner that reduces differential-to-common mode crosstalk. For example, as shown in
Referring to
The plug 300 of
In contrast, when a high frequency signal is input to the plug 300 from one of the pairs of insulated conductor (e.g., insulated conductors 291, 292) of cable 290, the signal is transferred from the cable 290 to the metal-plated vias 361, 362. The signal travels from these metal-plated vias 361, 362 along the conductive paths 381, 382 to the contact pads 351, 352 from which the signal is capacitively transferred to a pair of mating contact pads in the jack 400. The high frequency signal does not, however, travel along the conductive paths 371, 372 because the low pass filters 369 block the high frequency signal. Accordingly, when a high frequency signal is input to the plug 300, the plug automatically routes that signal to a separate set of output contacts.
It will be appreciated that the techniques described herein may also be combined with the techniques disclosed in co-pending U.S. Provisional Patent Application Ser. No. 61/531,723, titled Communications Connectors Having Frequency Dependent Communications Paths and Related Methods, filed Sep. 7, 2011 (herein “the '723 application”), the entire contents of which are incorporated herein by reference. For example, the '723 application teaches that low-crosstalk plug blades may be used in the communications plug, and that capacitors that are coupled to a non-signal current carrying portion of the plug blade may be used to increase the crosstalk levels to be within the industry-standardized ranges. As explained in the '723 application, this may improve the crosstalk performance for low frequency signals. As is also disclosed in the '723 application, the above-described capacitors are located between a pair of low pass filter banks in order to isolate these capacitors from the transmission path for the high frequency signals. Thus, it will be appreciated that similar techniques may be incorporated into the plug and jacks according to embodiments of the present invention.
As shown in
A plurality of jackwire contacts 431-438 are mounted in a cantilevered fashion on the printed circuit board 420 so as to extend into the plug aperture 414. The jackwire contacts 431-438 are arranged so that they will make physical and electrical contact with the respective blades of a mating communications plug that is received within the plug aperture 414. Any appropriate contacts may be used to implement the jackwire contacts 431-438. A plurality of output terminals 441-448 are also mounted on the printed circuit board 420 in a conventional fashion. In the depicted embodiment, the output terminals 441-448 are implemented as insulation displacement contacts (IDCs). 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 cover 418 includes a plurality of pillars that cover and protect the IDCs 441-448. Adjacent pillars are separated by wire channels. The slot of each of the IDCs 441-448 is 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 IDCs 441-448.
As is further shown in
Referring to
The jack 400 of
However, when a high frequency signal is passed through the plug 300, as is discussed above, this signal will appear on two of the contact pads (e.g., contact pads 351, 352) as opposed to on two of the plug blades 331-338. This high frequency signal is capacitively coupled to contact pads 451, 452 of jack 400, and then travels along the conductive paths 471, 472 to the IDCs 441, 442. The high frequency signal does not travel over conductive paths 461, 462 because the low pass filters 469 block the high frequency signal.
While not expressly described, it will be appreciated that a differential signal incident on the cable attached to the jack 400 will pass through the jack 400 to the plug 300 in the same manner (but reverse direction) as described above. In particular, if the differential signal is a low frequency signal, it will pass from the jack 400 to the plug 300 through the jackwire contacts (e.g., jackwire contacts 431, 432) to the corresponding plug blades 331, 332, whereas if the differential signal is a high frequency signal, it will pass from the jack 400 to the plug 300 through the jack contact pads (e.g., jack contact pads 451, 452) to the corresponding plug contact pads 351, 352.
Thus, as described above, the plug 300 and jack 400 may transmit and receive low frequency signals in a conventional manner using conventional plug blades and jackwire contacts, but may also transmit high frequency signals by providing a second, high frequency set of contacts on both the plug 300 and the jack 400. As noted above, in some embodiments, the second set of plug contacts may reactively as opposed to conductively couple with the second set of jack contacts. The use of such reactive coupling techniques may allow the contacts to also act as a high pass filter that blocks passage of lower frequency signals.
The combination of plugs and jacks according to embodiments of the present invention (e.g., the combination of the plug 300 and the jack 400) may provide a variety of advantages as compared to combinations of conventional plug and jack connectors.
As a first example, the plug-jack combinations according to embodiments of the present invention may include electrically parallel sets of conductive paths (with contacts in the plug and jack for each conductive path) that transmit signals across the plug-jack interface. In RJ-45 embodiments, this would mean as many as 16 conductive paths may be provided across the plug-jack interface. In some embodiments, these electrically parallel paths may be frequency dependent electrically parallel paths, with low frequency signals being carried on a first set of eight conductive paths and high frequency signals being carried on a second set of eight conductive paths that are electrically arranged in parallel to the path of the first set of conductive paths. The eight low frequency conductive paths may be designed to comply with all applicable industry standards so that the plugs and jacks according to embodiments of the present invention may be used with plugs and jacks manufactured by other vendors while complying with these industry standards. The high frequency conductive paths may be used, for example, to carry signals that are transmitted in frequency ranges above the frequency ranges specified in the industry standards.
As another example, the plug-jack combinations according to embodiments of the present invention may include reactive as opposed to conductive contacts. The use of reactive contacts can eliminate concerns associated with, for example, contact force and the problems of jackwire contacts that may be deformed for various reasons such as an operator accidentally inserting an RJ-11 plug into an RJ-45 jack that does not have adequate protection against jackwire contact deformation.
It will also be appreciated that numerous modifications may be made to the exemplary plug 300 and the exemplary jack 400 that are described herein. For example, the size and placement of the plug contact pads 351-358 and/or the jack contact pads 451-458 may be varied. For instance, in other embodiments, larger contact pads may be used in order to increase the signal coupling along the high frequency conductive paths. The distance between the contact pads, the size of the contact pads and other factors may be varied in order to achieve a desired or minimum level of signal coupling.
As another example, as mentioned above, in some embodiments, the contact pads 351-358 and 451-458 may be designed to conductively contact each other (i.e., a direct physical and electrical connection) and/or may be replaced with other types of conductive contacts such as spring contacts. In such designs, a band pass or high pass filter would typically be provided along each high frequency conductive path in order to prevent low frequency signals from traversing the plug-jack interface along the high frequency conductive paths.
As another example, both the plug 300 and the jack 400 are shown as including low pass filters 369, 469 along each low frequency conductive path, thus providing a low pass filter at each end of each low frequency conductive path. It will be appreciated, however, that in other embodiments, the low pass filters may be eliminated in either or both the plug and the jack along some or all of the low frequency conductive paths.
It will also be appreciated that a second set of contacts need not be provided for all of the differential pairs. By way of example,
Referring to
In the embodiment of
Referring back to
As is also shown in
Referring to
Eight plug contacts 731-738 are mounted on the top surface and/or a front edge of the printed circuit board 720. The plug contacts 731-738 may comprise, for example, conventional plug blades, skeletal plug blades, low-profile plug blades, conductive material deposited on the printed circuit board, etc. In the depicted embodiment, the plug contacts 731-738 are implemented as low profile plug blades. The plug contacts 731-738 may be spaced to comply with all appropriate standards for an RJ-45 plug. In addition to the plug contacts 731-738, two additional contacts 740, 742 are provided that are mounted on a top surface of the printed circuit board 720. Each contact 740, 742 is implemented as a springy strip of conductive metal such as beryllium-copper or phosphor-bronze. Each end of each contact 740, 742 may be attached or mounted to the printed circuit board 720 using known techniques such as, for example, compression contacts, eye-of-the-needle terminations or soldering. Each contact 740, 742 extends through a respective one of a pair of slots in the upper surface of the plug housing 710 (see
As should be readily apparent from the above discussion, the communication plug 700 may be designed to have the circuit configuration of the connector 500′ depicted in
When the communications plug 700 is mated with a conventional RJ-45 jack, the contacts 740, 742 are simply forced back inside the plug housing by the wall defining the top surface of the plug aperture of the jack, and the plug 700 and mating jack will operate like a conventional RJ-45 plug and jack. However, when the plug 700 is mated with a jack according to embodiments of the present invention, the spring contacts 740, 742 mate with respective corresponding contacts in the jack to provide a second electrically parallel communications path through the mated plug-jack connector for any differential signals that are received on pair 3. If the signal on pair 3 is a low frequency signal, it will be blocked by the high pass filters associated with contacts 740, 742, and hence the signal will travel from the plug to the jack (or vice versa) via plug blades 733, 736. In contrast, if the signal on pair 3 is a high frequency signal, then it will instead travel from the plug to the jack (or vice versa) via the contacts 740, 742.
It will be appreciated in light of the teachings of the present disclosure that it may be advantageous in some cases to ensure good mechanical compliance of the reactive coupling components (e.g., contacts) that are provided in certain embodiments of the present invention. In particular, it may be desirable in some cases to tightly control, for example, the distance between a pair of reactive coupling elements and/or to control the degree of overlap of two such components. Achieving such mechanical compliance may be difficult in some cases due to manufacturing variations and/or the amount of variation in the plug housing and/or the plug aperture of the jack that are allowed under the relevant industry standards. Using contacts such as, for example, the spring contacts 740, 742 of the plug of
It will also be appreciated that in further embodiments of the present invention the techniques described herein may be implemented in plugs and/or jacks that do not include a printed circuit board and/or that do not use a printed circuit board for implementing the high frequency contacts and high frequency conductive paths. By way of example, the embodiment of the communications plug pictured in
Referring first to
The contact pads 840, 842 comprise a pair of high frequency contacts for pair 3. An insulative material (e.g., a top surface of the printed circuit board 820) may cover each of the contact pads 840, 842. As shown in
As noted above, in some embodiments of the present invention, the second set of (high frequency) contacts in the plug may make direct physical and electrical contact with their corresponding contacts of the second set of (high frequency) contacts in the jack. For example, in one such embodiment, the communications jack 800 of
When the contacts 740, 742, 840 and 842 are implemented as conductive contacts, a high pass filter such as the high pass filter 228 of
As shown in
As is further shown in
While
In certain circumstances, there may be advantages to implementing the high pass filters entirely within the plug or entirely within the jack and using direct conductive contacts to transfer high frequency signals between the plug and the jack, as opposed to implementing the high pass filter as part of the second set of high frequency contacts as is done, for example, in the plug and jack discussed with respect to
Additionally, it may be difficult in some embodiments to ensure that sufficient signal energy couples between the plug and the jack when reactive contacts are used. In particular, in order to ensure that sufficient signal energy is coupled, it may be necessary to use relatively large contact pads. However, it may be difficult to use large contact pads due to the small size of an RJ-45 plug, particularly in embodiments in which high frequency conductive paths are provided for multiple pairs of conductors. As is known to those of skill in the art, most RJ-45 jacks and plugs have a very small form factor to begin with. According to embodiments of the present invention, as many as eight additional contacts may be added which must fit within this small form factor. If large contact pads must be used, it may be difficult to find room on the exterior surfaces of the plug and/or the jack to locate these relatively large contacts, and to do so in a way that has little coupling between the contacts. Thus, the use of conductive contacts for the high frequency conductive paths may reduce or eliminate the problem of finding suitable positions to locate each high frequency contact on the plug and the jack, and may also help ensure that the high frequency signals pass between the plug and jack with sufficient signal energy.
As another example, it may be advantageous to implement the high pass filters entirely within either the plug or the jack because it may be significantly easier to tune a capacitor that is implemented on a printed circuit board within a plug or jack than it is to tune a capacitor that is implemented between a contact on a plug and a mating contact on a jack. For example, to tune a capacitor on a printed circuit board, it is typically only necessary to order another printed circuit board that has a slightly revised capacitor design (e.g., the plates of the capacitor may be increased or decreased in size). In contrast, if the capacitors are implemented within the mating plug and jack contacts, it may be necessary to build the plug and jack in their entireties for each tuning operation. Thus, the process of designing the plug and jack may be simplified if the high pass filters are implemented entirely in either the plug or the jack.
As yet another example, it may be easier to implement more complex high pass filters (e.g., one involving a network of capacitors and inductors) if the high pass filter is implemented entirely within either the plug or the jack as compared to a high pass filter that is implemented at the plug-jack interface, as it may be difficult, if not impossible to implement shunt circuit elements within the plug and jack contacts for many contact designs. Finally, when the high pass filters are implemented entirely within either the plug or the jack, it may be readily easy to obtain higher capacitance and inductance values. For example, if additional capacitive coupling is required, additional capacitors may be implemented on additional layers of a multi-layer printed circuit board. Since it is relatively inexpensive and easy to add additional layers to a multi-layer printed circuit board, high pass filters with relatively large capacitors and inductors may readily be implemented within either the plug or the jack, whereas it may be significantly more difficult to obtain similar levels of capacitive and/or inductive coupling if the high pass filters are implemented between the plug and the jack contacts.
It will be appreciated that numerous modifications may be made to the various plugs and jacks according to embodiments of the present invention that are discussed above. For example, while in the embodiment of
As discussed above, in some embodiments each high pass filter may be implemented as a capacitor. In other embodiments, more sophisticated high pass filters may be used. For example, in some cases, each high pass filter may be implemented as a capacitor that is in series with an inductor. In some embodiments, the capacitor may be relatively small and the inductor may be relatively large, which may provide good filtering characteristics while also maintaining acceptable insertion loss and return loss performance. For example in some embodiments the ratio of the inductance of the series inductor (measured in nanohenries) to the capacitance of the series capacitor (measured in picofarads) may be between about 1 and about 10 (e.g., a 1 nanohenry inductor in series with a 1 picofarad capacitor would have a ratio at the lower boundary of this range, while a 10 nanohenry inductor in series with a 1 picofarad capacitor would have a ratio at the upper boundary of this range).
It will also be appreciated that aspects of the above-described embodiments may be mixed and matched to provide numerous additional embodiments. By way of example, reactive coupling may be used on the high frequency conductive paths between the plug and the jack for some pairs, while direct conductive coupling may be used on other of the pairs. Likewise, different filter designs may be used for different pairs. Thus, it will be appreciated that the features of the various embodiments described herein may be fully mixed and matched to provide numerous additional embodiments, and that all such embodiments are within the scope of the present invention.
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.
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.
As shown in
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 carry signals at different frequency bands across the plug-jack interface on separate, parallel, communications paths. Lower frequency signals may be carried across the plug-jack interface in a conventional manner and at conventional performance levels, thereby allowing the plugs and jacks according to embodiments of the present invention to comply with the various applicable industry standards. Higher frequency signals are carried across the plug-jack interface on a second set of conductive paths that use a separate, second sets of plug and jack contacts. These second sets of plug/jack contacts may be provided in a non-industry standardized configuration that is designed to reduce or minimize crosstalk between the pairs. By using crosstalk reduction techniques such as separation, shielding, and crosstalk compensation circuits that are located at the point that any offending crosstalk is injected it is believed that the second sets of contacts may be designed to exhibit far less crosstalk as compared to the crosstalk generated under the industry-standardized plug-jack interface. Thus, the high frequency paths may support high data rate signals due to these drastically reduced crosstalk levels.
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.
Spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper”, “top”, “bottom” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. Thus, the exemplary term “under” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
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.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes” and/or “including” when used in this specification, specify the presence of stated features, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, operations, elements, components, and/or groups thereof.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
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.
Although exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.
The present application claims priority under 35 U.S.C. §119 to U.S. Provisional Patent Application Ser. No. 61/602,186, filed Feb. 23, 2012, and to U.S. Provisional Patent Application Ser. No. 61/669,721, filed Jul. 10, 2012, the entire contents of both of which are incorporated herein by reference as if set forth in their entireties.
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