Abstract:
A contact ribbon configured to connect a cable to a substrate includes a plurality of signal contacts, a ground plane, and at least one ground contact extending from the ground plane. The plurality of signal contacts are connected by a support member, and the support member is removable after the plurality of signal contacts are connected to the cable.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to connectors for high-speed signal transmission. More specifically, the present invention relates to connectors in which wires are directly connected to contacts of the connectors. 
         [0003]    2. Description of the Related Art 
         [0004]    High-speed cable routing has been used to transmit signals between substrates, such as printed circuit boards, of electronic devices. Conventional high-speed cable routing often requires routing in very tight and/or low-profile spaces. However, as data rates increase (i.e., the frequency of the high-speed signal increases), the cost of high-performance high-speed transmission systems increases as well. High-speed signals transmitted from between substrates generally follow a path of:
       1) a trace of the transmitting substrate;   2) a first connector mounted to the transmitting substrate;   3) a substrate of a second connector that is inserted into the first connector;   4) a high-speed cable connected to the second-connector substrate at a transmitting end of the high-speed cable;   5) a substrate of a third connector connected the high-speed cable at a receiving end of the high-speed cable;   6) a fourth connector, mounted to the receiving substrate, that receives the third-connector substrate; and   7) a trace of the receiving substrate.       
 
         [0012]    Conventional high-speed cable assemblies typically include two connectors (i.e., the second and third connectors listed above) that are connected by high-speed cables. Accordingly, conventional high-speed cable routing also requires an additional two connectors (i.e., the first and fourth connectors listed above) to connect the high-speed cables to transmitting and receiving substrates. 
         [0013]    The signal quality is affected every time the transmitted signal transfers from each of the listed items above. That is, the signal quality is degraded when the signal is transmitted between 1) the trace of the transmitting substrate and 2) the first connector mounted to the transmitting substrate, between 2) the first connector mounted to the transmitting substrate and 3) the second-connector substrate that is inserted into the first connector, etc. The signal quality can even be affected within each of the items above. For example, a signal transmitted on the trace of the transmitting or receiving substrate can suffer significant insertion loss. 
         [0014]    High-speed cable assemblies are relatively expensive, due in part to the cost of high-speed cable and the two connectors that include substrates (i.e., the second and third connectors listed above). Each connector of the high-speed cable assembly also requires processing time. Thus, the full cost of a high-speed cable assembly cable includes the cable, the high-speed-cable-assembly connectors on each end of the cable, the processing time required for each of these connectors, and the area required on a substrate for each connector. 
         [0015]    To reduce the overall size of the high-speed cable assembly, smaller connectors and cables have been attempted. However, using smaller connectors and cables can both increase the cost and reduce the performance of high-speed cable assemblies. Eliminating the high-speed cable assembly has been attempted by transmitting the signal only on substrates. However, signals transmitted on a substrate generally have higher insertion losses compared to many cables, including, for example, micro coaxial (coax) and twinaxial (twinax) cables. Thus, eliminating the high-speed cable assembly can result in reduced signal integrity and degraded performance. 
         [0016]    Exotic materials and RF/Microwave connectors have been used to improve the performance of high-speed cable assemblies. However, such materials and connectors increase both the cost and the size of a high-speed cable assembly. Low-cost conductors, dielectrics, and connectors have been used to reduce the overall cost of systems that rely on high-speed cable routing. However, low-cost conductors, dielectrics, and connectors decrease the performance of high-speed cable assemblies and can also increase their size. 
       SUMMARY OF THE INVENTION 
       [0017]    To overcome the problems described above, preferred embodiments of the present invention provide a method of manufacturing a high-speed cable assembly and a high-speed cable assembly that is reduced in size, cheaper, and has improved performance. 
         [0018]    A contact ribbon according to a preferred embodiment of the present invention is configured to connect a cable to a substrate and includes a plurality of signal contacts, a ground plane, and at least one ground contact extending from the ground plane. The plurality of signal contacts are connected by a support member, and the support member is removable after the plurality of signal contacts are connected to the cable. 
         [0019]    Preferably, the plurality of signal contacts are initially connected to both the ground plane and the support member, and the plurality of signal contacts are disconnected from the ground plane before the signal contacts are connected to the cable. The contact ribbon is preferably included in a housing, and the support member is preferably removed from the contact ribbon after the contact ribbon is included in the housing. The support member is preferably removed after the contact ribbon is connected to the substrate. 
         [0020]    Preferably, the plurality of signal contacts are arranged in at least a first row and a second row, and the first row and the second row are offset from each other. 
         [0021]    The cable is preferably a twinaxial cable. A shield of the cable is preferably connected to the ground plane. 
         [0022]    A method of manufacturing a high-speed cable assembly according to another preferred embodiment of the present invention includes providing a contact ribbon with a plurality of signal contacts, a ground plane, and a support member such that the plurality of signal contacts are connected by the support member; connecting at least a first conductor at a first end of a cable to one of the plurality of signal contacts; connecting at least a second conductor at the first end of the cable to the ground plane; and removing the support member. 
         [0023]    Preferably, the first conductor is connected to the one of the plurality of signal contacts by crimping or soldering. The second conductor is preferably connected to the ground plane by soldering. 
         [0024]    The method of manufacturing a high-speed cable assembly preferably further includes forming a housing for the contact ribbon before the support member is removed. Preferably, the housing includes at least one hole, and the support member is removed by punching or cutting the support member through the at least one hole of the housing. 
         [0025]    The method of manufacturing a high-speed cable assembly preferably further includes attaching the high-speed cable assembly to a substrate before the support member is removed. Preferably, the one of the plurality of signal contacts is connected to a corresponding hole in the substrate by a press-fit connection or soldering or is connected to a corresponding pad on a surface of the substrate. 
         [0026]    The method of manufacturing a high-speed cable assembly preferably further includes forming a housing for the contact ribbon before the support member is removed, where the housing includes at least one hole, and inserting a weld tab into the at least one hole of the housing. Preferably, the method further includes attaching the high-speed cable assembly to a substrate by inserting a leg of the weld tab into a corresponding hole in the substrate. 
         [0027]    The support member is preferably a carrier attached to the one of the plurality of signal contacts or a tie bar connected between the one of the plurality of signal contacts and another one of the plurality of signal contacts. 
         [0028]    The method of manufacturing a high-speed cable assembly preferably further includes providing a second contact ribbon connected to a second end of the cable. Preferably, the plurality of signal contacts of the first contact ribbon are arranged in at least a first row and a second row, the first row and the second row are offset from each other, and a plurality of signal contacts of the second contact ribbon are respectively arranged in rows corresponding to the first row and the second row in an opposing manner such that an overall signal transmission length for each of the conductors of the cable is the same or substantially the same. 
         [0029]    Preferred embodiments of the present invention provide a high-speed cable assembly with a low-profile connection to a substrate, preferably having a height dimension of less than about 3 mm in above a surface of the substrate. Because the high-speed cable assembly connects perpendicularly or substantially perpendicularly to the substrate, zero keep-out space on the substrate is needed for slide insertion. Because there is no mating connector required on the substrate, the total amount of required system space, including on the substrate, is relatively small. The high-speed cable assembly also uses a low number of connectors and thus has few transitions in the signal transmission path, thus simplifying the signal transmission path, improving system performance, and reducing costs. 
         [0030]    The above and other features, elements, steps, configurations, characteristics and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]      FIGS. 1A and 1B  show a contact ribbon with press-fit contacts according to a first preferred embodiment of the present invention. 
           [0032]      FIGS. 2A and 2B  show a contact ribbon with solderable contacts according to the first preferred embodiment of the present invention. 
           [0033]      FIGS. 3 to 6B  show a process of providing a high-speed cable assembly according to the first preferred embodiment of the present invention. 
           [0034]      FIGS. 7A and 7B  show the high-speed cable assembly shown in  FIG. 6A  connected to a substrate. 
           [0035]      FIG. 7C  is a plan view of the substrate shown in  FIGS. 7A and 7B . 
           [0036]      FIGS. 8A to 13B  show specific applications of the first preferred embodiment of the present invention. 
           [0037]      FIGS. 14A and 14B  show a contact ribbon with press-fit contacts according to a second preferred embodiment of the present invention. 
           [0038]      FIGS. 15A and 15B  show a contact ribbon with solderable contacts according to the second preferred embodiment of the present invention. 
           [0039]      FIGS. 16A to 19  show a process of providing a high-speed cable assembly according to the second preferred embodiment of the present invention. 
           [0040]      FIGS. 20A and 20B  are detail views of the high-speed cable assembly connected to a substrate according to the second preferred embodiment of the present invention. 
           [0041]      FIG. 21  is top plan view of the substrate shown in  FIGS. 18 to 20B . 
           [0042]      FIGS. 22A to 27B  show specific applications of the second preferred embodiment of the present invention. 
           [0043]      FIG. 28  shows a contact ribbon with surface-mount contacts according to a third preferred embodiment of the present invention. 
           [0044]      FIGS. 29A to 33  show a process of providing a high-speed cable assembly according to the third preferred embodiment of the present invention. 
           [0045]      FIGS. 34A and 34B  show the high-speed cable assembly shown in  FIG. 33  connected to a substrate. 
           [0046]      FIG. 34C  is a plan view of the substrate shown in  FIGS. 34A and 34B . 
           [0047]      FIG. 35  shows a cable assembly with surface-mount contacts and separate twinaxial cables according to the third preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0048]    Preferred embodiments of the present invention will now be described in detail with reference to  FIGS. 1 to 35 . Note that the following description is in all aspects illustrative and not restrictive and should not be construed to restrict the applications or uses of the present invention in any manner. 
         [0049]      FIGS. 1A to 13B  show a high-speed cable assembly according to a first preferred embodiment of the present invention.  FIGS. 1A and 1B  show a contact ribbon  10  in accordance with the first preferred embodiment of the present invention. The contact ribbon  10  includes one or more ground contacts  11 , one or more first contacts  12 , and one or more second contacts  13  to provide physical and electrical connections to, for example, a substrate or an electrical connector. The first contacts  12  and the second contacts  13  are preferably staggered or offset with respect to each other in respective rows to reduce the pitch of the high-speed cable assembly. Tie bars  14  connect the first and second contacts  12  and  13  together to provide a rigid structure that structurally supports the first and second contacts  12  and  13  during manufacturing and assembling of the high-speed cable assembly. The ground contacts  11  are connected together by a ground plane  15 , which includes pilot holes  16  that provide guidance to stamp the contact ribbon  10 . Preferably, the first and second contacts  12  and  13  are also initially connected to the ground plane  15  to provide additional structural support during manufacturing and assembling of the high-speed cable assembly. 
         [0050]    As shown in  FIGS. 1A and 1B , the ground contacts  11 , the first contacts  12 , and the second contacts  13  are preferably included in a ribbon, that is, the contact ribbon  10 , and arranged such that individual contacts  11 ,  12 , and  13  can be formed by cutting the first and second contacts  12  and  13  from the ground plane  15  and removing the tie bars  14  that connect the first and second contacts  12  and  13 . The first and second contacts  12  and  13  preferably include a concave portion that defines a groove to receive, for example, center conductors of coaxial or twinaxial cables, as shown in  FIGS. 1B and 4B . Preferably, the staggering of the first and second contacts  12  and  13  on one end of the high-speed cable assembly is the opposite to the staggering of the first and second contacts  12  and  13  on the other end of the high-speed cable assembly such that the overall length of the transmission for each of the signals transmitted by the high-speed cable assembly is the same or substantially the same, within manufacturing tolerances. 
         [0051]    Preferably, the legs of ground contacts  11 , first contacts  12 , and second contacts  13  include a through-hole (e.g., an “eye-of-the-needle” configuration) to provide an oversize fit for press-fit mounting applications. Accordingly, when the legs are press-fit into corresponding mounting holes in a substrate, the legs deform to fit the corresponding mounting holes in the substrate to provide a secure electrical and mechanical connection between the contacts  11 ,  12 , and  13  and the substrate (for example, substrate  40  shown in  FIG. 7C ). 
         [0052]      FIGS. 2A and 2B  show a contact ribbon  10   a  in accordance with the first preferred embodiment of the present invention. Instead of the press-fit contacts  11 ,  12 , and  13  as shown in  FIGS. 1A and 1B , the contact ribbon  10   a  includes ground contacts  11   a , first contacts  12   a , and second contacts  13   a  that provide a solderable connection. That is, the contacts  11   a ,  12   a , and  13   a  have straight legs as compared to the “eye-of-the-needle” legs of the contacts  11 ,  12 , and  13 . Accordingly, the contacts  11   a ,  12   a , and  13   a  may be used, for example, in applications where it is undesirable to engage a connector to a substrate (e.g., printed circuit board) by a press-fit connection or to reduce manufacturing costs while maintaining the other advantages provided by the preferred embodiments of the present invention. 
         [0053]    However, the preferred embodiments of the present invention are not limited to the “eye-of-the-needle” and straight-leg configurations described above, and may include a combination of both press-fit and solderable contacts, or any type of suitable contact including, for example, pogo pins, one-piece contact solutions, two-piece contact solutions, compression contacts, pin and socket contacts, single-beam contacts, dual-beam contacts, multi-beam contacts, elastomeric contacts, directly soldered solutions, crimped contacts, welded contacts, etc. Other configurations that may be used with the preferred embodiments of the present invention include, for example, a square post, a kinked pin, an action pin, a Winchester C-Press® compliant pin, or any other suitable configuration. That is, any contact can be used that is connected to the PCB by heat, plastic deformation, or elastic deformation. 
         [0054]      FIGS. 3-7  show a process of providing the high-speed cable assembly according to the first preferred embodiment of the present invention. As shown in  FIG. 3 , the first and second contacts  12  and  13  that are to transmit signals are cut or stamped so that they are no longer connected to the ground plane  15 . The number of contacts  12  and  13  that are cut preferably corresponds to the number of contacts in the high-speed cable assembly. Preferably, not all of the contacts  12  and  13  are cut such that the rigid structure is maintained for the contact ribbon  10  during assembly and further manufacturing of the high-speed cable assembly. Further, one or more of the first and second contacts  12  and  13  may be left connected to the ground plane  15  to provide additional ground connection(s). 
         [0055]    Next, as shown in  FIG. 4A , a contact ribbon  10  is connected at both ends of a ribbonized twinaxial cable  20 .  FIG. 4B  is a perspective view of the connections between the contact ribbon  10  and the ribbonized twinaxial cable  20 . The ribbonized twinaxial cable  20  includes a shield  21 , pairs of first and second center conductors  22  and  23 , an insulator  24  for each pair of first and second center conductors  22  and  23 , and a jacket  25 . The first and second center conductors  22  and  23  are surrounded by the insulator  24 , the insulator  24  is surrounded by the shield  21 , and the shield  21  is surrounded by the jacket  25 . 
         [0056]    The shield  21  and the first and second center conductors  22  and  23  are the conductive elements of the ribbonized twinaxial cable  20 . The first and second center conductors  22  and  23  are arranged to carry electrical signals, whereas the shield  21  typically provides a ground connection. The shield  21  also provides electrical isolation for the first and second center conductors  22  and  23  and reduces crosstalk between neighboring pairs of the first and second center conductors  22  and  23  and between the conductors of any neighboring cables. 
         [0057]    The first and second center conductors  22  and  23  preferably have cylindrical or substantially cylindrical shapes. However, the first and second center conductors  22  and  23  could have rectangular or substantially rectangular shapes or other suitable shapes. The first and second center conductors  22  and  23  and the shield  21  are preferably made of copper. However, the first and second center conductors  22  and  23  and the shield  21  can be made of brass, silver, gold, copper alloy, any highly conductive element that is machinable or manufacturable with a high dimensional tolerance, or any other suitable conductive material. The insulator  24  is preferably formed of a dielectric material with a constant or substantially constant cross-section to provide constant or substantially constant electrical properties for the conductors  22  and  23 . The insulator  24  could be made of TEFLON™, FEP (fluorinated ethylene propylene), air-enhanced FEP, TPFE, nylon, combinations thereof, or any other suitable insulating material. The insulator  24  preferably has a round, oval, rectangular, or square cross-sectional shape, but may be formed or defined in any other suitable shape. The jacket  25  protects the other layers of the ribbonized twinaxial cable  20  and prevents the shield  21  from coming into contact with other electrical components to significantly reduce or prevent occurrence of an electrical short. The jacket  25  can be made of the same materials as the insulator  24 , FEP, or any suitable insulating material. 
         [0058]    As shown in  FIGS. 4A and 4B , portions of the first and second center conductors  22  and  23 , the insulator  24 , and the shield  21  are exposed before the ribbonized twinaxial cable  20  is connected to the contact ribbon  10 . The first and second center conductors  22  and  23  are connected to the respective first and second contacts  12  and  13  of the contact ribbon  10 . The first and second center conductors  22  and  23  are preferably fusibly connected (for example, by solder) to the first and second contacts  12  and  13  to ensure an uninterrupted electrical connection. Preferably, a hot-bar soldering or other soldering technique is used. However, it is possible to use other suitable methods to connect the first and second center conductors  22  and  23  to the first and second contacts  12  and  13 , e.g., crimping, sonically welding, conductive soldering, convective soldering, inductive soldering, radiation soldering, otherwise melting solder to hold the two parts together, pushing the two parts together with enough force to weld the two parts together, or micro-flaming. Preferably, the shield  21  is connected with the ground plane  15  by a hot-bar soldering process, although the shield  21  and the ground plane  15  may be connected by other processes, including the process described above with respect to the first and second center conductors  22  and  23  and the first and second contacts  12  and  13 . The pilot holes  16  in the ground plane  15  improve the solder connection between the shield  21  and the ground plane  15  by increasing the area through which solder can flow. The connections between the first and second contacts  12  and  13  to the first and second center conductors  22  and  23  and between the shield  21  and the ground plane  15  can occur either simultaneously or successively. 
         [0059]    Although the ribbonized twinaxial cable  20  is shown with a single shield  21  that surrounds all of the pairs of first and second center conductors  22  and  23 , the ribbonized twinaxial cable  20  may also be formed with a separate shield for each individual pair of first and second center conductors  22  and  23 . If separate shields are used, they are preferably connected to each other and to the ground plane  15  to provide a single, collective ground. However, it is not necessary for separate shields to touch each other after being connected to the ground plane  15 . Furthermore, other types of cables, such as coaxial cables, can be used in place of the ribbonized twinaxial cable  20 . 
         [0060]      FIG. 5  shows a step of overmolding a connector housing  30  on the contact ribbon  10  to form an electrical connector of the high-speed cable assembly. The connector housing  30  is formed with holes  34  that are arranged over the tie bars  14  of the contact ribbon  10  when the connector housing  30  is molded over the contact ribbon  10 . As shown in  FIGS. 6A and 6B , after overmolding the connector housing  30  on the contact ribbon  10 , the tie bars  14  are removed, preferably by a tool punching into the holes  34  of the connector housing  30 . Further, the portions of the contact ribbon  10  that laterally overhang from the connector housing  30  are removed, preferably by cutting or stamping. Accordingly, the first contacts  12  and the second contacts  13  are structurally and electrically disconnected from each other and from the ground plane  15 .  FIG. 6B  is a cross-sectional view taken along line A-A of  FIG. 6A  and shows the arrangement of the contact ribbon  10  and the twinaxial cable  20  within the connector housing  30 . Preferably, because the connector housing  30  is overmolded on the contact ribbon  10 , the connector housing  30  is a solid and rigidly supports the connections between the contact ribbon  10  and the twinaxial cable  20 . Additionally, the connector housing  30  may include shelf features, retention elements, and/or alignment features that help support the press-in force to retain the contact ribbon  10  within the connector housing  30 . 
         [0061]    Instead of using overmolding for the connector housing  30 , any housing can be used that allows the tie bars  14  between the contacts  12 ,  13  to be removed. Such housings include, for example, pre-molded, snap-on, sonically welded, screwed-on, and glued housings. However, overmolding is preferred for the connector housing  30  because of its simplicity and because it is easier for a tool to remove the tie bars  14 . Preferably, the connector housing  30  is made of plastic, for example, acrylonitrile butadiene styrene (ABS) plastic. 
         [0062]      FIGS. 7A to 7C  show the high-speed cable assembly shown in  FIG. 6A  connected to substrates  40 . Preferably, the high-speed cable assembly is connected by press-fitting or soldering to the substrates  40 , according to whether the press-fit contact ribbon  10  or the solderable contact ribbon  10   a  was included in the connector housing  30 . As shown in  FIG. 7C , the substrates  40  include a row of ground mounting holes  41 , a row of first mounting holes  42 , and a row of second mounting holes  43  that respectively receive the ground contacts  11  or  11   a , the first contacts  12  or  12   a , and the second contacts  13  or  13   a.    
         [0063]    If the press-fit contact ribbon  10  is used, the high-speed cable assembly can be press fit to the substrate  40  using a press-fit tool. The press-fit tool is preferably a simple tool, including, for example, a flat block attached to an arbor press, a tool with a cavity that aligns with the housing, a tap hammer, etc. That is, it is not necessary to use an expensive tool to transfer a force directly and individually to the back of each of the contacts  11 ,  12 , and  13 . Typically, the high-speed cable assembly is only mated to the substrate  40  once; however, it is possible to unmate the high-speed cable assembly and the substrate  40  and then to re-mate the high-speed cable assembly and the substrate  40 , if desired. For example, it is possible to remove the press-fit contacts  11 ,  12 , and  13  or to unsolder the solderable contacts  11   a ,  12   a , and  13   a.    
         [0064]    As explained below, the high-speed cable assembly can be connected to the same substrate or to different substrates.  FIGS. 8A to 13B  show various specific applications for the high-speed cable assembly.  FIG. 8A  is a perspective view of the connection between the high-speed cable assembly and the substrate  40  shown in  FIGS. 7A to 7C , and  FIG. 8B  is a detail view of the connector housing  30  engaging the substrate  40 . 
         [0065]      FIGS. 9A and 9B  show an edge-to-edge application in which the substrate  40  is connected to a substrate  40   a  that is co-planar or substantially co-planar and aligned along a common edge.  FIGS. 10A and 10B  show a right-angle application in which the substrate  40  is connected to a substrate  40   b  that is perpendicular or substantially perpendicular.  FIGS. 11A and 11B  show a board-to-board application in which the substrate  40  is connected to a substrate  40   c  that is parallel or substantially parallel, but not coplanar, for example, when the surfaces of the substrates  40  and  40   c  that are connected by the high-speed cable assembly are facing each other. 
         [0066]      FIG. 12A  shows a board-to-edge-card application in which one end of the high-speed cable assembly is connected to a relatively large substrate, such as a computer motherboard  50 , and the other end of the high-speed cable assembly is connected to a relatively small edge-card  60 .  FIG. 12B  is a detail view of the connection between the high-speed cable assembly and the computer motherboard  50  in the board-to-edge-card application, and  FIG. 12C  is a detail view of the connection between the high-speed cable assembly and the edge-card  60 .  FIG. 13A  shows a high-speed-flyover application in which both ends of the high-speed cable assembly are connected to the same substrate, such as the computer motherboard  50 .  FIG. 13B  is a detail view of the connection between the high-speed cable assembly and the computer motherboard  50  in the high-speed-flyover application. 
         [0067]      FIGS. 14A to 27B  show a high-speed cable assembly according to a second preferred embodiment of the present invention.  FIGS. 14A and 14B  show a contact ribbon  110  in accordance with the second preferred embodiment of the present invention. The contact ribbon  110  includes one or more ground contacts  111 , one or more first contacts  112 , and one or more second contacts  113  to provide physical and electrical connections to, for example, a substrate or an electrical connector. The first contacts  112  and the second contacts  113  are preferably staggered or offset with respect to each other in respective rows to reduce the pitch of the high-speed cable assembly. A carrier  117  connects the first and second contacts  112  and  113  together to provide a rigid structure that structurally support the first and second contacts  112  and  113  during manufacturing and assembling of the high-speed cable assembly. Preferably, the carrier  117  allows for the contact ribbon  110  to be easily manipulated and positioned, for example, by hand, and the carrier  117  may also include pilot holes that provide guidance to stamp the contact ribbon  110 . The ground contacts  111  are connected together by a ground plane  115 . Preferably, the first and second contacts  112  and  113  are also initially connected to the ground plane  115  to provide additional structural support during manufacturing and assembling of the high-speed cable assembly. 
         [0068]    As shown in  FIGS. 14A and 14B , the ground contacts  111 , the first contacts  112 , and the second contacts  113  are preferably included in a ribbon, that is, the contact ribbon  110 , and arranged such that individual contacts  111 ,  112 , and  113  can be formed by cutting the first and second contacts  112  and  113  from the ground plane  15  and removing the carrier  117 . The first and second contacts  112  and  113  preferably include a concave portion that defines a groove to receive, for example, center conductors of coaxial or twinaxial cables, as shown in  FIGS. 14A, 14B, and 16A to 16C . Preferably, the staggering of the first and second contacts  112  and  113  on one end of the high-speed cable assembly is the opposite to the staggering of the first and second contacts  112  and  113  on the other end of the high-speed cable assembly such that the overall length of the transmission for each of the signals transmitted by the high-speed cable assembly is the same or substantially the same, within manufacturing tolerances. 
         [0069]    Preferably, the legs of ground contacts  111 , first contacts  112 , and second contacts  113  include a through-hole (e.g., an “eye-of-the-needle” configuration) to provide an oversize fit for press-fit mounting applications. Accordingly, when the legs are press-fit into corresponding mounting holes in a substrate, the legs deform to fit the corresponding mounting holes in the substrate to provide a secure electrical and mechanical connection between the contacts  111 ,  112 , and  113  and the substrate (for example, substrate  140  shown in  FIG. 21 ). 
         [0070]      FIGS. 15A and 15B  show a contact ribbon  110   a  in accordance with the second preferred embodiment of the present invention. Instead of the press-fit contacts  111 ,  112 , and  113  as shown in  FIGS. 14A and 14B , the contact ribbon  110   a  includes ground contacts  111   a , first contacts  112   a , and second contacts  113   a  that provide a solderable connection. That is, the contacts  111   a ,  112   a , and  113   a  preferably include straight legs as compared to the “eye-of-the-needle” legs of the contacts  111 ,  112 , and  113 . Accordingly, the contacts  111   a ,  112   a , and  113   a  may be used, for example, in applications where it is undesirable to engage a connector to a substrate (e.g., printed circuit board) by a press-fit connection or to reduce manufacturing costs while maintaining the other advantages provided by the preferred embodiments of the present invention. However, the preferred embodiments of the present invention are not limited to the “eye-of-the-needle” and straight-leg configurations described above, and may include a combination of both press-fit and solderable contacts, or any type of suitable contact including those described above with respect to the first preferred embodiment of the present invention. 
         [0071]      FIGS. 16A to 19  show a process of providing the high-speed cable assembly according to the second preferred embodiment of the present invention. As shown in  FIGS. 16A to 16C , the first and second contacts  112  and  113  that are to transmit signals are cut or stamped so that they are no longer connected to the ground plane  115 . The number of contacts  112  and  113  that are cut preferably corresponds to the number of contacts in the high-speed cable assembly. Preferably, not all of the contacts  112  and  113  are cut such that the rigid structure is maintained for the contact ribbon  110  during assembly and further manufacturing of the high-speed cable assembly. Further, one or more of the first and second contacts  112  and  113  may remain connected to the ground plane  115  to provide additional ground connection(s). Preferably, the outermost ones of the first and second contacts  112  and  113  at the opposing sides of the contact ribbon  110  are left connected to the ground plane  115  to provide structural support during manufacturing and assembling of the high-speed cable assembly. 
         [0072]    Next, as shown in  FIG. 17 , the contact ribbon  110  is connected to a ribbonized twinaxial cable  20 . Preferably, the contact ribbon  110  is connected to the ribbonized twinaxial cable  20  in the same manner as the contact ribbon  10  of the first preferred embodiment of the present invention. That is, as shown in  FIG. 18 , the first and second center conductors  22  and  23  of the ribbonized twinaxial connector  20  are connected to the respective first and second contacts  112  and  113  of the contact ribbon  110 , and the shield  21  of the ribbonized twinaxial connector  20  is connected with the ground plane  115 . The connections between the first and second contacts  112  and  113  to the first and second center conductors  22  and  23  and between the shield  21  and the ground plane  115  can occur either simultaneously or successively. Although not shown, the contact ribbon  110  according to the second preferred embodiment of the present invention may also include pilot holes in the ground plane  115 , similar to the pilot holes  16  in the contact ribbon  10  of the first preferred embodiment of the present invention, in order to provide guidance to stamp the contact ribbon  110  and to improve the solder connection between the shield  21  and the ground plane  115  by increasing the area through which solder can flow. Furthermore, other types of cables, such as coaxial cables, can be used in place of the ribbonized twinaxial cable  20 . 
         [0073]    The contact ribbon  110 , with the ribbonized twinaxial cable  20  connected thereto, is then connected to a substrate  140 , as shown in  FIG. 18 . Preferably, the high-speed cable assembly is connected by press-fit or soldering to the substrate  140 , according to whether the press-fit contact ribbon  110  or the solderable contact ribbon  110   a  is used. As shown in  FIG. 21 , which is a top plan view of the substrate  140 , the substrate  140  includes a row of ground mounting holes  141 , a row of first mounting holes  142 , and a row of second mounting holes  143  that respectively receive the ground contacts  111  or  111   a , the first contacts  112  or  112   a , and the second contacts  113  or  113   a . As compared with the corresponding pairs of first and second mounting holes  41  and  42  of the first preferred embodiment of the present invention, the corresponding pairs of first and second mounting holes  141  and  142  of the second preferred embodiment of the present invention have a relatively larger spacing in order to accommodate for the attachment of the carrier  117 . 
         [0074]    If the press-fit contact ribbon  110  is used, the high-speed cable assembly can be press fit to the substrate  140  using a press-fit tool. The press-fit tool is preferably a simple tool, including, for example, a flat block attached to an arbor press, a tool with a cavity that aligns with the housing, a tap hammer, etc. That is, it is not necessary to use an expensive tool to transfer a force directly and individually to the back of each of the contacts  111 ,  112 , and  113 . Typically, the high-speed cable assembly is only mated to the substrate  140  once; however, it is possible to unmate the high-speed cable assembly and the substrate  140  and then to re-mate the high-speed cable assembly and the substrate  140 , if desired. For example, it is possible to remove the press-fit contacts  111 ,  112 , and  113  or to unsolder the solderable contacts  111   a ,  112   a , and  113   a.    
         [0075]    After the contact ribbon  110  or  110   a  is connected to the substrate  140 , the carrier  117  is removed as shown in  FIG. 19 . Preferably, the carrier  117  is scored so that it can be easily removed from the contact ribbon  110  by being twisted away from the contact ribbon  110 .  FIGS. 20A and 20B  are detail views of the high-speed cable assembly connected to substrate  140 , which provides a low profile. In particular, because the second preferred embodiment of the present invention does not include a connector housing, a profile even lower than that of the first preferred embodiment of the present invention can be obtained, and is as low as about 1.74 mm, for example. 
         [0076]    As explained below, the high-speed cable assembly can be connected to the same substrate or to different substrates.  FIGS. 22A to 27B  show various specific applications for the high-speed cable assembly.  FIG. 22A  is a perspective view of the connection between the high-speed cable assembly and the substrate  140  shown in  FIGS. 19 to 21 , and  FIG. 8B  is a detail view of the high-speed cable assembly engaging the substrate  140 . 
         [0077]      FIGS. 23A and 23B  show an edge-to-edge application in which the substrate  140  is connected to a substrate  140   a  that is co-planar or substantially co-planar and aligned along a common edge.  FIGS. 24A and 24B  show a right-angle application in which the substrate  140  is connected to a substrate  140   b  that is perpendicular or substantially perpendicular.  FIGS. 25A and 25B  show a board-to-board application in which the substrate  140  is connected to a substrate  140   c  that is parallel or substantially parallel, but not coplanar, for example, when the surfaces of the substrates  140  and  140   c  that are connected by the high-speed cable assembly are facing each other. 
         [0078]      FIG. 26A  shows a board-to-edge-card application in which one end of the high-speed cable assembly is connected to a relatively large substrate, such as a computer motherboard  150 , and the other end of the high-speed cable assembly is connected to a relatively small edge-card  160 .  FIG. 26B  is a detail view of the connection between the high-speed cable assembly and the computer motherboard  150  in the board-to-edge-card application, and  FIG. 26C  is a detail view of the connection between the high-speed cable assembly and the edge-card  160 .  FIG. 27A  shows a high-speed-flyover application in which both ends of the high-speed cable assembly are connected to the same substrate, such as the computer motherboard  150 .  FIG. 27B  is a detail view of the connection between the high-speed cable assembly and the computer motherboard  150  in the high-speed-flyover application. 
         [0079]      FIGS. 28 to 35  show a high-speed cable assembly according to a third preferred embodiment of the present invention.  FIG. 28  shows a contact ribbon  210  according to a third preferred embodiment of the present invention. The contact ribbon  210  includes one or more contacts  212  to provide physical and electrical connections to, for example, a substrate or an electrical connector. The contacts  212  are preferably included in a single row. However, adjacent ones of the contacts  212  may be staggered or offset with respect to each other to reduce the pitch of the high-speed cable assembly. Tie bars  214  connect to the contacts  212  together to provide a rigid structure that structurally supports the contacts  212  during manufacturing and assembling of the high-speed cable assembly. The contact ribbon  210  further includes a ground plane  215 , which contains pilot holes  216  that provide guidance to stamp the contact ribbon  210 . Preferably, the contacts  212  are also initially connected to the ground plane  215  to provide additional structural support during manufacturing and assembling of the high-speed cable assembly. 
         [0080]    As shown in  FIG. 28 , the contacts  212  are preferably included in a ribbon, that is, the contact ribbon  210 , and configured such that individual contacts  212  can be formed by cutting the contacts  212  from the ground plane  215  and removing the tie bars  214  that connect the contacts  212 . The contacts  212  may include a concave portion that defines a groove to receive, for example, center conductors of coaxial or twinaxial cables. Preferably, the contacts  212  have offset straight legs that provide a surface-mount connection to pads on a substrate (for example, the pads  241  on the substrate  240  shown in  FIG. 34C ). 
         [0081]      FIGS. 29A to 33  show a process of providing a high-speed cable assembly according to the third preferred embodiment of the present invention. As shown in  FIGS. 29A and 29B , the contacts  212  that are to transmit signals are cut or stamped so that they are no longer connected to the ground plane  215 . The number of contacts  212  that are cut preferably corresponds to the number of contacts in the high-speed cable assembly. Preferably, not all of the contacts  212  are cut such that the rigid structure is maintained for the contact ribbon  210  during assembly and further manufacturing of the high-speed cable assembly. For example, as shown in  FIGS. 29A and 29B , the outermost ones of the contacts  212  are preferably left connected to the ground plane  215  to provide ground connections and to provide structural support during manufacturing and assembling of the high-speed cable assembly. 
         [0082]    Next, as shown in  FIG. 30A , a contact ribbon  210  is connected at both ends of a ribbonized twinaxial cable  20 .  FIG. 30B  is a perspective view of the connections between the contact ribbon  210  and the ribbonized twinaxial cable  20 . Preferably, the contact ribbon  210  is connected to the ribbonized twinaxial cable  20  in the same manner as the contact ribbon  10  of the first preferred embodiment of the present invention. That is, as shown in  FIG. 30B , the first and second center conductors  22  and  23  of the ribbonized twinaxial connector  20  are connected to alternating ones of the contacts  212  of the contact ribbon  210 , and the shield  21  of the ribbonized twinaxial connector  20  is connected with the ground plane  215 . The connections between the contacts  212  and the first and second center conductors  22  and  23  and between the shield  21  and the ground plane  215  can occur either simultaneously or successively. 
         [0083]      FIG. 31  shows a step of overmolding a connector housing  230  on the contact ribbon  210  to form an electrical connector of the high-speed cable assembly. The connector housing  230  is formed with holes  234  that are arranged over the tie bars  214  of the contact ribbon  210  when the connector housing  230  is molded over the contact ribbon  210 . Weld tabs  218  are then inserted into weld tab holes  238  of the connector housing  230 , as shown in  FIG. 32 , such that the legs of the weld tabs  218  extend from the body of the connector housing  230 . As shown in  FIG. 33 , after overmolding the connector housing  230  on the contact ribbon  210 , the tie bars  214  are removed, preferably by a tool punching into the holes  234  of the connector housing  230 . Accordingly, the contacts  212  are structurally and electrically disconnected from each other and from the ground plane  15 . Further, any portions of the contact ribbon  210  that laterally overhang from the connector housing  230  (not shown) may be removed, preferably by cutting or stamping. 
         [0084]    Instead of using overmolding for the connector housing  230 , any housing can be used that allows the tie bars  214  between the contacts  212 ,  213  to be removed. Such housings include, for example, snap-on, sonically welded, screwed-on, and glued housings. However, overmolding is preferred for the connector housing  230  because of its simplicity and because it is easier for a tool to remove the tie bars  214 . 
         [0085]      FIGS. 34A and 34B  show the high-speed cable assembly shown in  FIG. 33  connected to substrates  240 .  FIG. 34C  is a plan view of one of the substrates  240  shown in  FIGS. 34A and 34B . Preferably, the high-speed cable assembly is initially connected by inserting the legs of the weld tabs  218  into the mounting holes  244  of the substrates  240 . Preferably, the mounting holes  244  of the substrates  240  are lined with solder so that the weld tabs  218  can be easily secured to the mounting holes  244  to fasten the high-speed cable assembly to the substrates  240 . Alternatively or in addition, the legs of the weld tabs  218  may include an “eye-of-the-needle” configuration to be press-fit to the mounting holes  244 . 
         [0086]    As shown in  FIGS. 34A and 34C , the substrates  240  include pads  241  that respectively align with the contacts  212  of the high-speed cable assembly. Preferably, the contacts  212  are secured to the pads  241  by a solder connection, although other connection types may be used, such as those described above with respect to the first and second preferred embodiments of the present invention. Preferably, the interior ones of the pads  241  are connected to signal traces on the substrates  240 , and the outermost ones of the pads  241  provide ground connections. However, other arrangements can be used, for example, every third one of the contacts  212  may provide a ground connection. 
         [0087]    The high-speed cable assembly according to the third preferred embodiment of the present invention can be connected to the same substrate or to different substrates, including the various specific applications shown in  FIGS. 8A to 13B  and  FIGS. 22A to 27B  of the first and second preferred embodiments of the present invention. 
         [0088]      FIG. 35  shows a modification of the third preferred embodiment of the present invention, which includes a high-speed cable assembly with surface-mount contacts and separate twinaxial cables. As shown in  FIG. 35 , in place of the ribbonized twinaxial cable  20 , separate twinaxial cables  20   a  may be used with the third preferred embodiment of the present invention. The separate twinaxial cables  20   a  each include a respective jacket  25   a  and a respective shield  21   a  that is connected to the ground plane  215 . Preferably, each of the separate twinaxial cables  20   a  are spaced apart from each other, such that a contact  212  connected to ground is included between each pair of contacts  212  associated with one of the separate twinaxial cables  20   a . Accordingly, as shown in  FIG. 35 , the substrates  240   a  are preferably modified so that signal traces are not included for these additional ground connections. Furthermore, other types of cables, such as coaxial cables, can be used in place of the separate twinaxial cables  20   a.    
         [0089]    Although the high-speed cable assembly according to the preferred embodiments of the present invention preferably includes the ribbonized twinaxial cable  20 , the present invention is not limited thereto. For example, the high-speed cable assembly may include one or more separate twinaxial cables that each include a single pair of center conductors (for example, the twinaxial cable  20   a  shown in  FIG. 35 ), a ribbonized coaxial cable, or one or more coaxial cables that each include only a single center conductor. Furthermore, other types of cables may be used. 
         [0090]    In addition to reducing cross-talk between center conductors, a contact connected to ground may be included between each pair of center conductors of twinaxial cables or ribbonized twinaxial cables, for example, as shown in  FIG. 35 . Similarly, a contact connected to ground may be included between each center conductor of coaxial cables or ribbonized coaxial cables. 
         [0091]    While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.