Patent Publication Number: US-9843135-B2

Title: Configurable, high-bandwidth connector

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to electrical connectors. More specifically, the present invention relates to high-bandwidth connectors with multiple parallel connections. 
     2. Description of the Related Art 
     Electrical connectors are used to place electrical devices in communication with one another, for example, to connect an electrical device or cable to a printed circuit board (PCB). A typical connector includes one or more contacts that electrically and mechanically connect the connector to one or more corresponding pads of a circuit board. The electrical and mechanical connection between a contact and a pad is typically provided by a fusible material, such as solder. 
     Although a cable typically provides a signal path with high signal integrity (for example, a shielded cable such as a coaxial cable or twinaxial cable), an electrical path through a connector that attaches the cable to a PCB usually provides a signal path with lower signal integrity, especially at higher frequencies. Such electrical paths through connectors often have much higher loss than a shielded cable and are far more susceptible to interference and cross-talk. That is, known connectors have a limited ability to propagate high-bandwidth signals without loss or back reflections. 
     In addition, known connectors are generally inflexible regarding the number, type, and diameter of cables that can be used. Known electrical connectors are also typically designed to be tuned to a specific impedance. Accordingly, if different connector types and/or impedance profiles are needed for electrical device(s) mounted on a PCB, a different electrical connector is required for each particular impedance profile of the electrical device so that each electrical connector can perform optimally at the necessary impedance profile of the electrical device. Thus, according to conventional approaches, many different electrical connectors must be purchased or manufactured for electrical devices that require different electrical profiles, which results in significant material and labor costs. 
     Many known connectors use “horizontal mounting” in which cables and connectors are oriented parallel or substantially parallel to the major planar surfaces of a main mounting surface or PCB. Horizontal mounting requires that the connector be connected at an edge of the main mounting surface or PCB, which provides less nearby mounting space for electronic components. Thus, known horizontal connectors tend to increase the path length of signals not transmitted through a cable and require different housings for connectors with different numbers of contacts. 
     SUMMARY OF THE INVENTION 
     To overcome the problems described above, preferred embodiments of the present invention provide a configurable, high-bandwidth connector that supports different contact pitches, different numbers of cables, and different cable diameters. Further, the preferred embodiments of the present invention significantly reduce or minimize the length of a path along which a signal is not transmitted through a cable, which supports high-bandwidth operation of the connector. 
     A connector mountable to a main printed circuit board (PCB) according to a preferred embodiment of the present invention includes at least one carrier, at least one cable mounted to the at least one carrier, and an interposer that routes signals and ground connections between the at least one cable and the main PCB when the connector is mounted to the main PCB. The at least one cable is vertically mounted in the connector such that the at least one cable is perpendicular or substantially perpendicular to a mounting surface of the main PCB. 
     The at least one cable is preferably soldered to the at least one carrier. The at least one cable is preferably a coaxial cable, a twinaxial cable, or a discrete, unshielded wire. Preferably, the at least one cable includes a plurality of cables mounted to a first carrier of the at least one carrier. Preferably, the at least one cable includes a first cable mounted to a first carrier of the at least one carrier and includes a second cable mounted to a second carrier of the at least one carrier, and the first cable and the second cable include different size center conductors or different characteristic impedances. 
     The connector preferably further includes an intermediate PCB arranged between the at least one carrier and the interposer. A signal path of the at least one cable is preferably connected to a signal path of the intermediate PCB. The at least one carrier is preferably electrically connected to a ground path via or a ground region of the intermediate PCB. 
     A ground path or ground shield of the at least one cable is preferably connected to the at least one carrier. The at least one carrier preferably includes prongs that are aligned with a signal conductor of the at least one cable along a length of the at least one carrier such that the prongs of the at least one carrier and the signal conductor of the at least one cable define a single row. The at least one carrier preferably includes tabs that are offset from a signal conductor of the at least one cable. 
     The interposer preferably includes at least one guide hole arranged to mate with at least one alignment pin of the main PCB to align at least one contact of the interposer with at least one contact of the main PCB. The interposer preferably includes compression contacts or solderable contacts on at least one surface. 
     The connector preferably further includes a housing, the at least one carrier, a portion of the at least one cable, and the interposer are preferably inside of the housing. 
     Preferably, the at least one carrier includes at least one carrier hole; the housing includes at least one lateral housing hole; the at least one carrier hole is arranged to align with the at least one lateral housing hole; and a rod extends into each of the at least one lateral housing hole and through the at least one carrier hole to mechanically secure the at least one carrier to the housing. Preferably, the housing includes at least one vertical housing hole arranged to receive a guide mounted to the main PCB, and the connector is secured to the main PCB by a fastener. The fastener is preferably a threaded screw. 
     A connector mountable to a main printed circuit board (PCB) according to a preferred embodiment of the present invention includes at least one carrier, at least one cable mounted to the at least one carrier, and at least one press-fit contact that is connected to the at least one cable and that routes signals between the at least one cable and the main PCB when the connector is mounted to the main PCB. The at least one cable is vertically mounted in the connector such that the at least one cable is perpendicular or substantially perpendicular to a mounting surface of the main PCB. 
     The connector further preferably includes a ground plate connected to the at least one carrier. The connector further preferably includes a clip to which the ground plate is connected. The clip preferably includes at least one groove that receives the at least one cable. The at least one cable preferably is a twinaxial cable. 
     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 
         FIG. 1A  is an exploded perspective view of a configurable, high-bandwidth connector according to a preferred embodiment of the present invention. 
         FIG. 1B  is a perspective view of the connector shown in  FIG. 1A  mounted to a main PCB. 
         FIG. 2  is a side view of an interposer with dual compression contacts included in the connector shown in  FIG. 1A . 
         FIG. 3A  is a perspective view of a cable end termination of a cable included in the connector shown in  FIG. 1A . 
         FIGS. 3B and 3C  are side and perspective views of the cable shown in  FIG. 3A  mounted to a carrier. 
         FIG. 4  is a perspective view of a completed cable/carrier assembly including a plurality of cables with the cable end termination shown in  FIG. 3A  mounted to the carrier shown in  FIGS. 3B and 3C . 
         FIGS. 5A and 5B  are side and perspective views of the cable/carrier assembly shown in  FIG. 4  mounted to an intermediate PCB. 
         FIG. 5C  is a perspective view showing the intermediate PCB shown in  FIGS. 5A and 5B  fully populated with a plurality of the cable/carrier assemblies shown in  FIG. 4 , defining a connector assembly. 
         FIGS. 5D ( 1 ) to  5 D( 8 ) are side and perspective views showing a method of assembling the cable/carrier assembly shown in  FIG. 4 , mounting the cable/carrier assembly shown in  FIG. 4  to the intermediate PCB shown in  FIGS. 5A and 5B , and forming the connector assembly shown in  FIG. 5C . 
         FIG. 6A  is a perspective view of a housing being mounted to the connector assembly shown in  FIG. 5C . 
         FIGS. 6B ( 1 ) to  6 B( 4 ) are side and perspective views showing a method of introducing rods into the housing shown in  FIG. 6A . 
         FIG. 7  is a cross-sectional side view of the connector shown in  FIGS. 1A and 1B  mounted to a main PCB. 
         FIG. 8  is a view of the lower surface of the intermediate PCB shown in  FIGS. 5A to 5C . 
         FIG. 9  is a perspective view of a connector using a surface-mount-technology intermediate PCB according to a preferred embodiment of the present invention. 
         FIG. 10  is a perspective view of a connector without an intermediate PCB according to a preferred embodiment of the present invention. 
         FIG. 11  is a perspective view of a connector with twinaxial cable according to a preferred embodiment of the present invention. 
         FIGS. 12 and 13  are side views of a connector with press-fit contacts according to a preferred embodiment of the present invention. 
         FIG. 14  is a top perspective view of the housing of the connector shown in  FIGS. 12 and 13 . 
         FIG. 15  is a perspective view of a portion of the cable/carrier assembly used with the connector shown in  FIGS. 12 and 13 . 
         FIG. 16  is a perspective view of a portion of the twinaxial cable shown in  FIG. 15 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Preferred embodiments of the present invention will now be described in detail with reference to  FIGS. 1 to 16 . 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. 
       FIGS. 1A to 8  show a configurable, high-bandwidth connector  1  in accordance with a preferred embodiment of the present invention.  FIG. 1A  is an exploded perspective view of the connector  1 , and  FIG. 1B  is a perspective view of the connector  1  shown in  FIG. 1A  mounted to a main PCB  60 . 
     As shown in  FIG. 1A , the connector  1  includes a housing  10 , a connector assembly  3 , and an interposer  50 . The connector assembly  3  includes cable/carrier assemblies  2  and an intermediate PCB  40 , and the cable/carrier assembly  2  includes cables  20  and a carrier  30 . Any number of cable/carrier assemblies  2  and any number of cables can be used. The connector  1  can transmit high-bandwidth signals between the cables  20  and the main PCB  60 . The connector  1  can include different cable types, cable diameters, and contact pitches. Any suitable substrate can be used instead of main PCB  60 . 
     Any suitable electronic components, such as integrated circuits, resistors, capacitors, and inductors, can be mounted to the main PCB  60 . For simplicity, such electronic components are not shown in  FIG. 1A . The main PCB  60  preferably includes a contact matrix  61 , guides  64 , and alignment pins  63 . The contact matrix  61  provides electrical connection points for the signals transmitted to and from the cables  20 . The guides  64  provide rough alignment for the connector  1  to the main PCB  60 , and the guides  64  preferably have internal threads that mate with fasteners  13  to secure the connector  1  to the main PCB  60 . The alignment pins  63 , as most easily seen in  FIG. 10 , provide high precision alignment, preferably for at least the intermediate PCB  40  and the interposer  50 . Although a preferable alignment tolerance is about ±0.002″, this tolerances could be more or less. 
       FIG. 2  is a side view of the interposer  50  included in the connector  1  shown in  FIG. 1A . As shown in  FIG. 2 , the interposer  50  can have dual compression contacts that include first compression contacts  51  on an upper surface and second compression contacts  52  on a lower surface. The interposer  50  can be made with typical PCB materials, including, for example, FR4 and METRON 6. The upper and lower compression contacts  51  and  52  can be connected to each other by through hole vias in the interposer  50 . 
     The interposer  50  is preferably arranged between the intermediate PCB  40  and the main PCB  60 , as shown in  FIG. 1A . The interposer  50  routes signals and ground connections to and from the intermediate PCB  40  and the main PCB  60 . The first compression contacts  51  of the interposer  50  mate with vias  41  of the intermediate PCB  40 , and the second compression contacts  52  of the interposer  50  mate with the contact matrix  61  on the main PCB  60 . Interposer  50  can be, for example, the Z-Ray™ interposer manufactured by Samtec Inc. of New Albany, Ind., but any other suitable interposer could also be used. For example, the interposer  50  can preferably have a contact pitch of between about 0.8 mm and about 1.0 mm, within manufacturing tolerances, but other contact pitches can be used. The interposer  50  determines the contact count and/or contact density of the connector  1 . For example, the interposer  50  can have 1,024 contact/in 2 , but other contact densities are possible. 
     The interposer  50  preferably includes double compression contacts as shown in  FIG. 2 , but other contact arrangements can be used, including, for example, compression contacts on one side of the interposer  50  and solder balls on the other side of the interposer  50 . Preferably, the compression contacts include a spring that provides the mechanical force to make physical and electrical contact between the interposer contacts (e.g., first and second compression contacts  51  and  52 ) and contacts on the mating components, including the vias  41  of the intermediate PCB  40  and the contact matrix  61  of the main PCB  60 . The dual compression contacts of the interposer  50  permit electrical connections to be made without soldering the interposer  50  to either the intermediate PCB  40  or the main PCB  60 . However, if the interposer  50  only includes single compression contacts, the solder balls on the opposite surface of the single compression contacts are typically used to electrically connect the interposer  50  to the contact matrix  61  of the main PCB  60  by soldering the interposer  50  to the main PCB  60 . However, solder balls can also be used to electrically connect the interposer  50  to the intermediate PCB  40 . 
     The interposer  50  preferably includes guide holes  53  that receive the alignment pins  63  of the main PCB  60  to align the second compression contacts  52  of the interposer  50  with the contact matrix  61  on the main PCB  60 . However, the guide holes  53  can be replaced by any other suitable type of alignment feature(s). 
     An intermediate PCB  40  can be adjacent to the interposer  50 . The intermediate PCB  40  provides a routing path for signals and ground connections, as well as mechanical support for one or more carriers  30 . The intermediate PCB  40  receives and supports the one or more carriers  30  on the side of the intermediate PCB  40  opposite to the interposer  50 . Although five carriers  30  are shown in  FIGS. 1A and 1B , any number of carriers  30  can be used, including, for example, a single carrier  30 , as shown in  FIG. 5B . The carriers  30  are preferably soldered to the intermediate PCB  40 . Alternatively, the carriers  30  could be mounted to the intermediate PCB  40  in any suitable manner, including, for example, being press-fit to the intermediate PCB  40 . The carriers  30  provide mechanical support for the cables  20  and electrical paths for ground connections. 
     The intermediate PCB  40  preferably includes guide holes  43  that receive the alignment pins  63  of the main PCB  60  to align the vias  41  of the intermediate PCB  40  with the first compression contacts  51  on the interposer  50 . However, the guide holes  43  can be replaced by any other suitable type of alignment feature(s). 
     The cables  20  are attached to the carriers  30 . Preferably, the cables  20  include one or more center conductors  21  surrounded by a dielectric  22 , a ground shield  23 , and an outer insulation  24 . Any suitable type of cable can be used, including, for example, coaxial cables (as shown in  FIGS. 1A-8 ) or twinaxial cables (as shown in  FIGS. 11-13, 15, and 16 ). However, the cables  20  can alternatively be discrete, unshielded wire. The cables  20  can include the same or different size center conductors  21 , including, for example, 30 AWG (American Wire Gauge), 32 AWG, or 34 AWG. Other sizes or gauges can also be used. The cables  20  can also have the same or different characteristic impedances, including, for example, 50 Ω, 80Ω, or 100Ω. Other cable impedance values can also be used. 
     Preferably, the connector  1  includes a housing  10  that provides mechanical support and strain relief for the cables  20 . The housing  10  can be inexpensively fabricated from molded plastic, for example. The housing  10  can be made of other suitable materials, including, for example, plated plastic, Cu-metal injected molding, zinc casting, brass, aluminum, and lossy liquid crystal polymer (LCP). If the housing includes a conductive material, then the housing can provide a ground or shielding. The housing  10  preferably includes vertical housing holes  14  that receive fasteners  13 . Fasteners  13  secure the connector  1  to the main PCB  60 . Preferably, the fasteners  13  are threaded screws that engage with internal threads in the guides  64 . The fasteners  13  are preferably made from a durable material such as brass. However, any suitable metal could be used. However, other suitable types of fasteners  13  and/or fastening arrangements can be used to secure the connector  1  to the main PCB  60 . For example, instead of being threaded screws, the fasteners  13  could be latches or snap arms, which could be made of metal or plastic. 
       FIG. 1B  shows the connector  1  attached to the main PCB  60 . Only the fasteners  13 , the housing  10 , the cables  20 , and the main PCB  60  are shown in  FIG. 1B . All the other elements shown in  FIG. 1A  are present in the assembly (carriers  30 , intermediate PCB  40 , interposer  50 , etc.), but are not visible because they are obscured by the housing  10 . The fasteners  13  have been tightened down to secure the connector  1  to the main PCB  60 . As shown in  FIG. 1B , the cables  20  connected to the connector  1  are in an orientation at the point of attachment to the connector  1  that is perpendicular or substantially perpendicular within manufacturing tolerances to a major planar surface of the main PCB  60 . This type of mounting is referred to as “vertical mounting” in contrast to the more commonly-used “horizontal mounting” in which cables are parallel or substantially parallel to a major planar surface of substrate. Because the cables  20  can be bent, the portion of the cables  20  spaced away from the point of attachment can have any orientation. This is one of the benefits of using a cable. “Vertical mounting” and “horizontal mounting” refer to the orientation of the cable  20  at the point of attachment and does not refer to the orientation of the cable  20  spaced away from the point of attachment where the cable can be bent in any orientation. One advantage of vertical mounting is that the trace lengths between the connector  1  and any electronic components mounted to the main PCB  60  can be significantly reduced or minimized because these electronic components can be mounted around the periphery of the connector  1 . In contrast, horizontal mounting requires the connector to be connected at an edge of the main mounting surface or substrate, which provides less nearby mounting space for electronic components. 
     A method of assembling the connector  1  is described in more detail below, with respect to  FIGS. 3A to 6B ( 4 ). 
       FIGS. 3A to 4  show a process of preparing the cable/carrier assembly  2 . More specifically,  FIG. 3A  is a perspective view of an end of one of the cables  20  included in the connector  1  shown in  FIG. 1A .  FIGS. 3B and 3C  are side and perspective views of the cable shown in  FIG. 3A  mounted to a carrier  30 .  FIG. 4  is a perspective view of a completed cable/carrier assembly  2  including a plurality of the cables  20 , with an end as shown in  FIG. 3A , mounted to the carrier  30  shown in  FIGS. 3B and 3C . 
       FIG. 3A  shows an end of one of the cables  20 . The end of the cable  20  is stripped so that the center conductor  21  is exposed and extends past the end of the dielectric  22 . The ground shield  23  is also stripped back so that a short length of dielectric  22  is exposed. In addition, the outer insulation  24  of the cable  20  is stripped back so that a length of the ground shield  23  is exposed. Although  FIG. 3A  shows a coaxial cable, other types of cable can be used with appropriate modifications to the assembly procedures. For example, if a twinaxial cable  20   t  is used, as shown in  FIGS. 11 and 16 , two center conductors are included in each cable, and each of these center conductors is stripped back in a similar manner. Preferably, the length of the center conductor  21  not surrounded by the ground shield  23  is significantly reduced or minimized to curtail reflection losses and crosstalk. The center conductor  21  can be made of any suitable conductive material, including, for example, Ag-plate copper and Sn-plated copper. The dielectric  22  can be made of any suitable dielectric material, including, for example, Teflon®, fluorinated ethylene propylene (FEP), perfluoroalkoxy alkane (PFA), polytetrafluoroethylene (PTFE), and expanded PTFE (EPTFE). The ground shield can be any suitable conductive material, including, for example, Ag-plate copper, Sn-plated copper, and copper foil. The outer insulation can be made of any suitable insulating material, including, for example, polyvinyl chloride (PVC), terpolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride copolymer (THV), Teflon®, FEP, PFA, PTFE, and EPTFE. 
     The carrier  30  can be inexpensively fabricated from a stamped plated metal. For example, the carrier  30  can be fabricated from a beryllium copper alloy, but any other suitable material(s) can also be used. As shown in  FIG. 3C , the carrier  30  preferably includes carrier holes  35 , prongs  33 , and tabs  31  that help with alignment, improve mechanical integrity, and help establish a stable and effective electrical ground. The prongs  33  and tabs  31  are preferably arranged in an alternating pattern such that each tab  31  has prongs  33  on both sides of the tab  31  along the length of the carrier  30 , as shown in  FIG. 3C . The carrier holes  35  are preferably arranged along the length of the carrier  30 , as shown in  FIGS. 3B and 3C . 
       FIGS. 3B and 3C  show the connection between the cable  20  and the carrier  30 . Preferably, the ground shields  23  of the cables  20  are attached to the carrier  30  using solder, which provides both a good mechanical and electrical connection between the ground shields  23  of the cables  20  and the carrier  30 . However, the cables  20  can be attached to the carrier  30  in any other suitable manner, including, for example, crimping, ultrasonic welding, resistance welding, and laser soldering. The cable  20  can be positioned on the carrier  30  to align or substantially align within manufacturing tolerances the cable  20  with a tab  31  and/or a carrier hole  35 , as shown in  FIGS. 3B and 3C . The tabs  31  provide an extended surface for soldering the ground shields  23  of the cables  20  to the carrier  30 , which provides mechanical strength and rigidity to the cable/carrier assembly  2  and which act as a further grounding shield for the center conductor  21 . The carrier holes  35  provide alignment features for the cables  20 , improve the strength of the solder bond between the cables  20  and carrier  30 , and help provide strain relief for the cables  20 . The cables  20  can be positioned on the carrier  30  so that the end of each of the center conductors  21  is aligned or substantially aligned within manufacturing tolerances with, or slightly protrudes past, the end of each of the corresponding prongs  33 . The center conductors  21  and prongs  33  can be aligned in a single row. The prongs  33  provide electrical ground connections adjacent to the center conductors  21 , which improves impedance matching for the signal paths through the connector  1 . 
     The solder connection between the cables  20  and carrier  30  is preferably made using a hot-bar solder process. First, the carrier  30  and the ground shields  23  of the cables  20  are pre-tinned prior to application of pulsed heat by a hot-bar solder tool. Preferably, the hot-bar solder tool includes alignment features that help position the cables  20  with respect to the carrier  30 . After a first cable  20  is installed on the carrier  30 , other cables (labeled  20 ′ to  20 ″″ in  FIG. 4 ) can be installed in a similar manner to form the cable/carrier assembly  2  as shown in  FIG. 4 . The cables  20  can be simultaneously or nearly simultaneously soldered to the carrier  30 . Alternatively, the cables  20  can be sequentially soldered to the carrier  30 . If a defect is found or occurs in one of the cables  20 , the cable/carrier assembly  2  can be reworked by removing the defective cable and soldering in a replacement cable. 
       FIG. 4  shows the carrier  30  with five mounted cables (labeled  20 ,  20 ′,  20 ″,  20 ′″,  20 ″″ in  FIG. 4 ), which populate all the cable positions on the carrier  30  shown in  FIG. 4 . However, the carrier  30  can have fewer than five cable positions or more than 5 cable positions. In addition, not every cable position of the carrier  30  needs to be populated with a cable  20 . Different numbers of cables  20  can be readily accommodated on the carrier  30  by appropriately populating the cable positions and scaling the length of the carrier  30 . The cable positions of the carrier  30  can be populated by the same type or by different types of cables. Different cable/carrier assemblies can also be used in the connector assembly  3 . For example, as shown in  FIG. 11 , twinaxial cables  20   t  can be used in place of, or in addition to, the cables  20 , which are coaxial cables. Preferably, the two center conductors of the twinaxial cables  20   t  are both situated between each prong  33  of the carrier  30 . 
       FIGS. 5A to 5D ( 8 ) show a process of mounting the cable/carrier assembly  2  to the intermediate PCB  40  to form the connector assembly  3 . More specifically,  FIGS. 5A and 5B  are side and perspective views of the cable/carrier assembly  2  shown in  FIG. 4  mounted to the intermediate PCB  40 .  FIG. 5C  is a perspective view showing the intermediate PCB  40  shown in  FIGS. 5A and 5B  fully populated with the cable/carrier assemblies  2  shown in  FIG. 4 , thereby forming the connector assembly  3 .  FIGS. 5D ( 1 ) to  5 D( 8 ) are side and perspective views showing a method of assembling the cable/carrier assembly  2  shown in  FIG. 4 , mounting the cable/carrier assembly  2  shown in  FIG. 4  to the intermediate PCB  40  shown in  FIGS. 5A and 5B , and forming the connector assembly  3  shown in  FIG. 5C . 
       FIGS. 5A and 5B  show the connection between the cable/carrier assembly  2  and the intermediate PCB  40 . The vias  41  of the intermediate PCB  40  can be positioned in one or more rows  41 ′, as shown in  FIG. 5B . The prongs  33  of the carrier  30  and the center conductors  21  of the cables  20  are located in the vias  41  of the intermediate PCB  40 . For an intermediate PCB  40  with multiple rows  41 ′ of vias  41 , each via row  41 ′ can be mated with a single cable/carrier assembly  2 . For an intermediate PCB  40  with only a single via row  41 ′, cable/carrier assembly  2  can be mated to that single via row  41 ′. It is also possible that one via row is mated with two or more cable/carrier assemblies  2 . The intermediate PCB  40  and the cable/carrier assemblies  2  can be soldered together. For example, the solder can be applied to the center conductors  21 , prongs  33 , and vias  41  as a solder paste and then reflowed to provide good mechanical and electrical connections between the cable/carrier assemblies  2  and the intermediate PCB  40 . 
     As shown in  FIGS. 7 and 8 , the vias  41  extend through the intermediate PCB  40  to the opposing, second side of the intermediate PCB  40 , terminating in signal path vias  41   a  and ground path vias  41   b . Preferably, each of the signal path vias  41   a , which are connected to the center conductors  21 , is surrounded or substantially surrounded by a corresponding ground region  41   c  as the signal path via  41   a  traverses the intermediate PCB  40  to significantly reduce or minimize crosstalk, loss, and back reflection as signals are transmitted through the connector  1 . 
       FIG. 5C  shows cable/carrier assemblies  2  mounted to the intermediate PCB  40 , forming the connector assembly  3 . In  FIG. 5C , each cable/carrier assembly  2  preferably has five cables  20 , and the intermediate PCB  40  preferably has five via rows  41 ′, each of which is populated with a corresponding cable/carrier assembly  2 . Thus, the connector assembly  3  includes 5×5=25 total high-bandwidth signal channels. Each signal channel is preferably able to support multi-GHz data transmission bandwidths. More preferably, the data transmission rates are at least 28 GHz. The data transmission rates can be compatible with various industrial standards such as, but not limited to, Infiniband, Gigabit Ethernet, Fibre Channel, SAS, PCIe, XAUI, XLAUI, XFI, and the like. 
     Each center conductor  21  of the cables  20  is preferably surrounded by two prongs  33  of the carriers  30  on the cable/carrier assembly  2 , which are electrically connected to ground. Each center conductor  21  can also be adjacent to two tabs  31 , one on the cable/carrier assembly  2  holding the center conductor  21  and one on an adjacent cable/carrier assembly  2 . The prongs  33  and tabs  31  help to shield signals being transmitted through the center conductors  21 . Although  FIG. 5C  shows that all of the cables  20  are the same, different cable types and sizes can be used in a single connector. For example, a single connector can include coaxial cable, twinaxial cable, and/or cable of discrete wires. Accordingly, the connector  1  can be easily adapted or optimized for each specific application. 
       FIGS. 6A to 6B ( 4 ) show a process of assembling the connector  1  by mounting the housing  10  to the connector assembly  3 . More specifically,  FIG. 6A  is a perspective view of the housing  10  being mounted to the connector assembly  3  shown in  FIG. 5C .  FIGS. 6B ( 1 ) to  6 B( 4 ) are side and perspective views showing a method of introducing rods  15  into the housing  10  shown in  FIG. 6A . 
       FIG. 6A  shows some of the final steps in assembling the connector  1 . As described above, the connector assembly  3  can include multiple cable/carrier assemblies  2  connected to the intermediate PCB  40 . The housing  10  is positioned over the connector assembly  3  such that the housing  10  surrounds or substantially surrounds the connector assembly  3  with the cables  20  protruding through a cable opening  12  in the housing  10 . In many applications, the length of the cables  20  can have a length of 1 m or less; however, this is not a limitation and longer cable lengths can be used. The housing  10  can be secured to the connector assembly  3  with one or more rods  15 . Preferably, the rods  15  pass through lateral housing holes  16  in the housing  10  and engage with carrier holes  35  of the carriers  30 , providing a mechanical connection between the housing  10  and connector assembly  3 . After inserting the rods  15 , the rods  15  can be secured to the housing  10  with an adhesive or in some other suitable manner. The fasteners  13  (not shown in  FIG. 6A ) can be inserted into the vertical housing holes  14  to allow attachment of the connector  1  to the main PCB  60  using the interposer  50  as shown in  FIGS. 1A and 1B . In addition, the housing can be filled with epoxy after the cables  20  are connected to provide additional mechanical strength and strain relief. Any suitable non-conductive epoxy can be used. 
       FIG. 7  is a cross-sectional side view of the connector  1  shown in  FIGS. 1A and 1B  mounted to the main PCB  60 .  FIG. 7  shows a schematic cross-section of the connector  1  attached to the main PCB  60 . The connector  1  includes cables  20  mounted to the carrier  30 , as described above. The connector  1  is electrically connected to the main PCB  60  using the interposer  50  between the connector assembly  3  and the main PCB  60 . The prongs  33  of the carrier  30  and the center conductors  21  of the cables  20  fit into vias  41  in the intermediate PCB  40 . 
     The vias  41  in the intermediate PCB  40  can be blind vias. Blind vias can be formed by first forming a via through the intermediate PCB  40 , filling a portion of the via with a conductive material (shown by the rectangles with broken lines in  FIG. 7 ), and then plating the portion of the via into which the prong  33  or center conductor  21  will be inserted. 
     Electrically conductive signal paths (corresponding to signal path vias  41   a  in  FIG. 7 ) route signals to and from the center conductors  21  of the cables  20  through the intermediate PCB  40  and the interposer  50  from/to the main PCB  60 . Electrically conductive ground paths (corresponding to ground path vias  41   b  in  FIG. 7 ) establish a ground region substantially surrounding the signal paths through the intermediate PCB  40  and the interposer  50 . The signal path length between the end of the ground shield  23  and entry into the main PCB  60  is relatively short (preferably less than about 5 mm), which significantly reduces or minimizes the length of possible impedance mismatch between the cable  20  and the various elements of the connector  1 . 
       FIG. 8  is a view of lower surface of the intermediate PCB  40  shown in  FIGS. 5A to 5C .  FIG. 8  shows the second side of the intermediate PCB  40 . In  FIG. 8 , the cables  20  can be mounted to a first (upper) surface of the intermediate PCB  40  (the side of the intermediate PCB  40  shown in  FIG. 1A ), as described above. A second (lower) surface of the intermediate PCB  40  includes a regular array of signal paths. As shown in  FIG. 8, 25  signal paths (corresponding to signal path vias  41   a ) are arranged in a 5×5 array. However, more or fewer signal paths can be used. Each signal path can be surrounded by a ground region  41   c . The ground region  41   c  is the region defined by the ground signal paths (corresponding to ground path vias  41   b ) that surround each signal path and that are electrically connected together. These electrical connections can be made using suitable patterning techniques used in PCB fabrication. In addition, the ground region  41   c  can extend into the main PCB  60 , which further reduces crosstalk between the signal paths. 
       FIG. 9  is a perspective view of connector  101  using a surface-mount intermediate PCB  140 , according to another preferred embodiment of the present invention. For clarity, the housing  10  is not shown in  FIG. 9 . As shown in  FIG. 9 , the intermediate PCB  40  that uses via-based mounting can be replaced with an intermediate PCB  140  that uses surface mounting. The assembly and method of assembly of the connector  101  is generally similar to the connector  1  described above, except that the vias  41  of the intermediate PCB  40  have been eliminated, and surface-mount technology is used to connect the cable/carrier assembly  2  and the intermediate PCB  140 . When the surface-mount intermediate PCB  140  is used, the lengths of the prongs  33  of the carrier  30  and the lengths of the stripped center conductor  21  of the cables  20  can be modified from the lengths described above. In particular, the ends of the prongs  33  and the center conductors  21  preferably lie in a common plane or substantially a common plane within manufacturing tolerances so that surface-mount connections between pads  141  of the surface-mount PCB  140  and the prongs  33  and center conductors  21  can be made simultaneously or substantially simultaneously within manufacturing tolerances. The surface-mount connections are preferably made using suitable surface-mount soldering techniques. Surface-mount technology can reduce connector cost, shorten the signals paths through the main PCB  60 , and enable shorter pitch dimensions. 
       FIG. 10  is a perspective view of a connector  201  without an intermediate PCB. For clarity, the housing  10  is not shown in  FIG. 10 .  FIG. 10  shows a connector  201  that does not include the intermediate PCB  40 . The assembly and method of assembly of the connector  201  is generally similar to the connector  1  described above, except that the intermediate PCB  40  has been eliminated. As shown in  FIG. 10 , electrical connections are made directly from the prongs  33  of the carrier  30  and the center conductors  21  of the cables  20  to the contacts  51  of interposer  50 . The prongs  33  of the carrier  30  and the center conductors  21  of the cable  20  are arranged such that they align with and make electrical connection with the contacts  51  of the interposer  50 . The contacts  51  of the interposer  50  can be the first compression contacts  51  described above, although other contact types can be used, for example, cantilevered-type connections or other types of electrical connections that can be made by mechanical contact. 
       FIG. 10  shows a cover  236  that is preferably included in the connector  201  and that surrounds the connections between the cables  20  and the carrier  30  (for clarity, one of the carriers  30  is shown without a cover  236 ). Although not shown, the housing  10  can be included with the connector  201 . Since the connector  201  does not include the intermediate PCB  40 , the manufacturing cost can be reduced. In addition, the length of the signal path outside of the cable  20  can be short, which reduces loss and crosstalk and which supports high-bandwidth operation. 
       FIG. 11  is a perspective view of a connector  301  with twinaxial cables  20   t . For clarity, the housing  10  is not shown in  FIG. 10 . As discussed above with respect to  FIG. 4 , the carrier  30  can have any number of cable positions. However, different types of cables can be used, and different cable/carrier assemblies can also be used. As shown in  FIG. 11 , twinaxial cables  20   t  can be used in place of the (coaxial) cables  20  discussed above. Twinaxial cables  20   t  include two center conductors situated between each prong  33 . 
       FIGS. 12 and 13  show a connector  401  with press-fit contacts  421 ,  422 ,  423 . The connector  401  is connected to a main PCB (not shown in  FIGS. 12 and 13 ) by inserting the press-fit contacts  421 ,  422 ,  423  into holes in the main PCB. The holes in the PCB are arranged in the same arrangement as the press-fit contacts  421 ,  422 ,  423 . Because the press-fit contacts  421 ,  422 ,  423  connect to the main PCB instead of the compression contacts  52 , a fastener  13  is not needed to ensure a physical and electrical connection between the connector  401  and the main PCB. In addition, because the press-fit contacts  421  are connected to the twinaxial cables  20   t , the connector  401  does not include an intermediate PCB  40  or an interposer  50 . 
     The connector  401  includes a housing  410  that includes an alignment post  411 . Twinaxial cables  20   t  are attached to the housing  410 . Although twinaxial cables  20   t  are attached to the connector  401  in  FIGS. 12 and 13 , it is possible to use coaxial cables or other suitable cables. The center conductors  424  (not visible in  FIGS. 12 and 13  but shown in  FIG. 15 ) of the twinaxial cables  20   t  are connected to the press-fit contacts  421 . For example, as shown in  FIG. 16 , the center conductors  424  can be directly connected to the press-fit contacts  421  by soldering. Differential signals can be transmitted by the twinaxial cable  20   t  and the press-fit contacts  421 . Press-fit contacts  422  can be grounded, which can reduce cross-talk between adjacent pairs of press-fit contacts  421 . 
     For simplicity, only a single row of press-fit contacts is shown in each of  FIGS. 12 and 13 . In both of  FIGS. 12 and 13 , adjacent pairs of press-fit contacts  421  are separated by press-fit contact  422 , but the adjacent pairs of press-fit contacts  421  in  FIGS. 12 and 13  are shifted with respect to each other. In  FIG. 12 , starting from the left, the first pair of press-fit contacts  421  is defined by the third and fourth contacts, and in  FIG. 13 , starting from the left, the first pair of press-fit contacts  421  is defined by the second and third contacts.  FIG. 12  includes a dummy press-fit contact  423  on the left side, and  FIG. 13  includes a dummy press-fit contact  423  on the right side. Other arrangements of press-fit contacts  421 ,  422 ,  423  can be used. For example, it is possible not to use grounded press-fit contacts  422  and/or dummy press-fit contacts  423 . 
       FIG. 14  is a top perspective view of the housing  410 , and  FIG. 15  is a perspective view of a portion of the cable/carrier assembly  402  that is inserted into the housing  410 . The housing  410  includes slots  412  and grooves  413  that receive the cable/carrier assembly  402 . Any number of slots  412  and grooves  413  can be used. The cable/carrier assembly  402  includes a carrier  430 , a clip  440 , and a ground plate  450 . The carrier  430  is connected to the twinaxial cables  20   t  and the press-fit contacts  421 ,  422 ,  423 . Any number of twinaxial cables  20   t  can be used. The carrier  430  can be a plastic that is molded around the press-fit contacts  421 . 
     The clip  440  holds the ground plate  450  and includes grooves that receive the twinaxial cables  20   t . The grooves of the clip  440  support the twinaxial cables  20   t . Any number of grooves can be included in the clip  440 . The ground plate includes press-fit contacts  422 . The ground plate  450  is attached to the carrier  430  in any suitable manner such that the press-fit contacts  422  are located between pairs of press-fit contacts  421  to provide a ground-signal-signal-ground arrangement of contacts. The ground plate  450  can be made of any suitable conductive material. Although  FIG. 15  shows that one ground plate  450  is used with the cable/carrier assembly  402 , it is possible to use more than one ground plate  450 . For example, a second ground plate could be used on the opposite or same side of the cable/carrier assembly  402  as the ground plate  450  shown in  FIG. 15 . When the connector  401  is connected to a main PCB, the ground plate  450  can be connected to ground in the main PCB. The cable/carrier assembly  402  is configured such that the press-fit contacts  421 ,  422 ,  423  are aligned in a single row. 
       FIG. 16  is a perspective view of the end of one of the twinaxial cables  20   t  shown in  FIG. 15 . The twinaxial cable  20   t  of  FIG. 16  is similar to the coaxial cable  20  of  FIG. 3 , except that the twinaxial cable  20   t  includes two center conductors  424  instead of a single center conductor  21 . The twinaxial cable  20   t  includes an outer insulation  427  that surrounds a ground shield  426  that surrounds a dielectric  425  that surrounds the two center conductors  424 . This arrangement of the twinaxial cable  20   t  allows differential signals to be transmitted by the twinaxial cable  20   t . As shown in  FIG. 15 , the two center conductors  424  can be directly attached to the press-fit contacts  421 . Typically, the center conductors  424  are soldered to the press-fit contacts  421 , but the center conductors  424  can be attached to the press-fit contacts in any suitable manner. 
     Any suitable contact can be used instead of the press-fit contacts  421 ,  422 ,  423 . For example, pogo pins, mill-max terminals and sockets, and through-hole contacts that are soldered on the bottom of the main PCB could be used instead of press-fit contacts  421 ,  422 ,  423 . 
     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.