High-frequency cable coupler and cable assembly

Abstract

The utility model relates to a high-frequency cable coupler and a cable assembly. Compact cable couplers connect cables with different wire gauges and do not interfere with electrical performance up to very high frequencies. Each cable coupler has a pair of conductive elements having first and second contact portions on opposite ends that terminate the wires of the first and second cables. A housing surrounds the conductive element, including a cable attachment. The conductive layer extends from the first cable to the second cable and is conformal with the underlying surface. The housing has a region having a lower dielectric constant adjacent the cable attachment. A parameter of the cable coupler in each of the plurality of portions may be selected to provide a matched impedance through the coupler. Such couplers enable dense connection of small diameter cables with connectors while large diameter cables provide low loss routing to remote locations to achieve high density signal connections with high signal integrity at frequencies sufficiently high to support 224 Gbp.

Description

TECHNICAL FIELD

[0001] The present patent application relates generally to interconnect systems, such as interconnect systems that include cables and electrical connectors. BACKGROUND

[0002] Electronic systems are assembled from a plurality of interconnected components. Often, the components are mounted to a printed circuit board (PCB), which provides both mechanical support for the components and an electrically conductive structure that carries electrical power to the components and provides signal paths between components attached to the PCB.

[0003] Sometimes, the PCB is combined with an electrical connector. The connector provides a separable interface so that the PCBs in the system can be manufactured at different times or at different locations, and simply assembled into the system. A known arrangement for combining multiple printed circuit boards is to have one printed circuit board serve as a backplane. Other printed circuit boards, referred to as “daughter boards” or “daughter cards,” can be connected through the backplane.

[0004] The backplane is a printed circuit board to which many connectors can be mounted. The electrically conductive traces in the backplane can be electrically connected to the signal conductors in the connectors so that signals can be routed between the connectors. The daughter cards can also have connectors mounted on them. The connectors mounted on the daughter cards can be plugged into the connectors mounted on the backplane. In this way, signals can be routed between the daughter cards through the backplane.

[0005] Connectors can also be used in other configurations for interconnecting printed circuit boards. Sometimes, one or more smaller printed circuit boards can be connected to another larger printed circuit board. In such configurations, the larger printed circuit board can be referred to as a “motherboard,” and the printed circuit boards connected to it can be referred to as daughter boards. Likewise, boards of the same size or similar size can sometimes be arranged in parallel. The connectors used in these applications are often referred to as “stacking connectors” or “mezzanine connectors.”

[0006] In some cases, the distance between components can be longer than can be reliably connected through traces in a PCB. Cables can be used to route signals between components because cables can be routed through curved paths where it is difficult to install a rigid PCB, or can be manufactured to have less signal loss per inch than a PCB. Cables with larger diameter wires can have less signal loss than cables with smaller diameter wires.

[0007] Cables provide signal paths with high signal integrity, particularly for high frequency signals such as 40 Gbps and above using NRZ or PAM4 protocols. Each cable has one or more signal conductors, each of which is surrounded by a dielectric material. The insulated conductors are in turn surrounded by a conductive layer. A protective jacket, often made of plastic, can surround these components. The jacket or other portions of the cable can include fibers or other structures for mechanical support.

[0008] One type of cable construction, referred to as a "dual-axial cable," is configured to support transmission of differential signals and has a balanced pair of signal wires embedded in a dielectric material and surrounded by a conductive layer. The conductive layer is often formed using a foil, such as aluminum-coated Mylar. Dual-axial cables can also have a drain wire. Unlike the signal wires, which are typically surrounded by a dielectric, the drain wire can be uncoated so that it contacts the conductive layer at multiple points throughout the length of the cable.

[0009] Cables can be terminated with connectors, forming a cable assembly. The connectors can be inserted into mating connectors, which in turn are connected to components to be connected, or the connectors can mate directly to a PCB or other substrate. At the end of the cable, where the cable is terminated to a connector or other termination structure, different lengths of the protective jacket, dielectric, and foil can be removed, leaving portions of the signal wires and drain wire, if present, and the foil shield exposed at that end of the cable. These conductors can be attached to the connector or other termination structure. The signal wires can be attached to conductive elements that serve as mating contacts in the connector. The drain wire or foil shield can be attached to ground conductors in the termination structure. In this way, any ground return path can continue from the cable to the termination structure.

[0010] To receive the connector of the cable assembly, a connector referred to as an "I / O connector" can be mounted to a PCB, often at an edge of the PCB. The connector can be configured to receive a plug at one end of the cable assembly, such that the cable is connected to the PCB through the I / O connector. The other end of the cable assembly can be connected to another electronic device.

[0011] Cables have also been used within the same electronic device to make connections. For example, cables have been used to route signals from an I / O connector to a processor assembly that is located inside the PCB, away from the edge where the I / O connector is mounted. In other configurations, both ends of a cable can be connected to different PCBs within the same PCB or within the same housing. Cables can be used to carry signals between components mounted to a PCB with less signal loss than if the signals were routed through traces within the PCB, where they are close to the PCB's edge. Utility content

[0012] Aspects described herein relate to high frequency cable couplers and electronic systems thereof.

[0013] Some embodiments relate to a cable coupler. The cable coupler can include: a pair of conductive elements, each of the pair of conductive elements including a first contact portion, a second contact portion opposite the first contact portion, and a middle portion between the first contact portion and the second contact portion; a cable including a pair of wires, each of the pair of wires including a mounting end disposed between the pair of conductive elements and attached to the first contact portion of a respective one of the pair of conductive elements; and a housing holding the pair of conductive elements, the housing including a first material having a first dielectric constant and a second material disposed between the mounting ends of the pair of wires of the cable, the second material having a second dielectric constant less than the first dielectric constant.

[0014] Some embodiments relate to a cable coupler. The cable coupler can include: a conductive element including a first contact portion, a second contact portion opposite the first contact portion, and a middle portion between the first contact portion and the second contact portion, the first contact portion including a first notch having a first width, the first notch configured to have a first wire having a first diameter attached thereto, the second contact portion including a second notch having a second width, the second notch configured to have a second wire having a second diameter attached thereto, the second diameter different than the first diameter; and a housing holding the conductive element.

[0015] Optionally, the housing includes a first material having a first dielectric constant and a second material disposed proximate the mounting ends of the wires; and the second material has a second dielectric constant less than the first dielectric constant.

[0016] Optionally, the second material is air.

[0017] Optionally, the second material extends a length along the mounting ends of the wires of the cable, the length being in a range of 0.5 mm to 2 mm.

[0018] Optionally, the cable coupler includes a conductive layer bounding the housing.

[0019] Optionally, for the pair of conductive elements: the first contact portions are separated from each other by a first distance; the second contact portions are separated from each other by a second distance; and the second distance is greater than the first distance.

[0020] Optionally, for the pair of conductive elements: the middle portions are separated from each other by a third distance; and the third distance is less than the first distance.

[0021] Optionally, for the pair of conductive elements: each conductive element includes a transition portion between the intermediate portion and the second contact portion; and the transition portions are offset from one another.

[0022] Optionally, the second material has a width substantially equal to the third distance.

[0023] Optionally, each conductive element of the pair of conductive elements includes a wide side and an edge joining the wide side; and the pair of conductive elements is disposed in an edge-to-edge configuration.

[0024] Optionally, for the pair of conductive elements: the first contact portion includes a first edge facing one another; the second contact portion includes a second edge facing one another; the intermediate portion includes a third edge facing one another; the first edge is offset from the respective third edge by a first width; the second edge is offset from the respective third edge by a second width; and the second width is greater than the first width.

[0025] Optionally, the mounting ends of the pair of conductive elements are welded to the first edges of the first contact portions of the respective conductive elements.

[0026] Optionally, the cable is a first cable; and the cable coupler includes a second cable, the second cable including a pair of conductive elements, each conductive element of the pair of conductive elements including a mounting end disposed between the pair of conductive elements and attached to the second edges of the second contact portions of the respective conductive elements.

[0027] Optionally, the second material of the housing is also disposed between the mounting ends of the pair of conductive elements of the second cable.

[0028] Some embodiments relate to a cable coupler. The cable coupler can include: at least one conductive element, each conductive element of the at least one conductive element including a first contact portion, a second contact portion opposite the first contact portion, and an intermediate portion between the first contact portion and the second contact portion; a housing at least partially surrounding the at least one conductive element; and a conductive layer conformably applied on the housing.

[0029] Optionally, the at least one electrically conductive element is a pair of electrically conductive elements; and the cable coupler further comprises: a first cable, the first cable comprising a pair of first conductive wires, each of the pair of first conductive wires comprising a first mounting end disposed between the pair of electrically conductive elements, the first mounting ends of the pair of first conductive wires being attached to respective ones of the first contact portions of the pair of electrically conductive elements; and a second cable, the second cable comprising a pair of second conductive wires, each of the pair of second conductive wires comprising a second mounting end disposed between the pair of electrically conductive elements, the second mounting ends of the pair of second conductive wires being attached to respective ones of the second contact portions of the pair of electrically conductive elements.

[0030] Optionally, the electrically conductive layer is electrically connected to the shield layers of the first and second cables.

[0031] Optionally, the housing comprises a first pocket disposed between the first mounting ends of the first cable and a second pocket disposed between the second mounting ends of the second cable; and the first and second pockets have a smaller dielectric constant than the rest of the housing.

[0032] Optionally, the first and second pockets have the same dielectric constant.

[0033] Optionally, the first and second pockets are filled with air.

[0034] Optionally, each of the first and second pockets is a cuboid.

[0035] Optionally, the first and second pockets have different dielectric constants.

[0036] Optionally, the first pocket has a first width and a first thickness; the second pocket has a second width and a second thickness; the second width is greater than the first width; and the second thickness is greater than the first thickness.

[0037] Optionally, the first pocket has a first length in a longitudinal direction; and the second pocket has a second length equal to the first length.

[0038] Optionally, the housing comprises a first portion enclosing the first contact portions of the pair of electrically conductive elements and the first mounting ends of the first cable, and a second portion enclosing the second contact portions of the pair of electrically conductive elements and the second mounting ends of the second cable; and the second portion of the housing is wider and thicker than the first portion of the housing.

[0039] Optionally, the housing encloses the first mounting ends of the first cable and the second mounting ends of the second cable; and the electrically conductive layer comprises a first portion conforming to a perimeter of the first cable and a second portion conforming to a perimeter of the second cable.

[0040] Some embodiments relate to a cable assembly. The cable assembly can include: a plurality of cable couplings, each of the plurality of cable couplings including: at least one conductive element, each of the at least one conductive element including a first contact portion, a second contact portion opposite the first contact portion, and an intermediate portion between the first contact portion and the second contact portion; and a housing at least partially surrounding the at least one conductive element; an electrical connector including a plurality of conductive elements, each of the plurality of conductive elements including a mating end and a mounting end opposite the mating end; and a plurality of cables, each of the plurality of cables including at least one wire, each of the at least one wire including a first mounting end and a second mounting end opposite the first mounting end, wherein, for each of the plurality of cables: the first mounting end of the at least one wire is attached to a respective first contact portion of the at least one conductive element of a respective cable coupling of the plurality of cable couplings; and the second mounting end of the at least one wire is attached to a respective mounting end of a respective conductive element of the plurality of conductive elements of the electrical connector.

[0041] Optionally, the plurality of cable couplings are aligned in a plurality of rows; and for each row, the cable couplings have a center-to-center distance no greater than 2.4 mm.

[0042] Optionally, the cable couplings in adjacent rows are aligned and have a center-to-center distance no greater than 2.0 mm.

[0043] Optionally, the plurality of cables are a plurality of first cables, each of the plurality of first cables including at least one wire having a first diameter; and the cable assembly includes a plurality of second cables, each of the plurality of second cables including at least one wire having a second diameter greater than the first diameter, each of the at least one wire having the second diameter including a first mounting end attached to a respective second contact portion of the at least one conductive element of a respective cable coupling of the plurality of cable couplings.

[0044] Optionally, the electrical connector is a first electrical connector; the cable assembly includes a second electrical connector; and for each of the plurality of second cables, each of the at least one wire having the second diameter includes a second mounting end terminated at the second electrical connector.

[0045] Some embodiments relate to a method of interconnecting a first cable having a first wire gauge and a second cable having a second wire gauge different from the first wire gauge. The method can include: providing at least one conductive element, each of the at least one conductive element including a first contact portion and a second contact portion opposite the first contact portion; forming a housing to at least partially surround the at least one conductive element; and applying a conductive layer on the housing.

[0046] Optionally, forming the housing includes forming a first cavity filled with air between the first contact portions of the pair of conductive elements; and forming a second cavity filled with air between the second contact portions of the pair of conductive elements.

[0047] Optionally, the method includes welding a wire of the first cable to the first contact portion of the at least one conductive element; and welding a wire of the second cable to the second contact portion of the at least one conductive element.

[0048] Optionally, the conductive layer is applied by shrinking a tube that includes an inner conductive layer, wherein at least a portion of the housing is disposed within the tube.

[0049] Optionally, shrinking the tube includes applying heat to the tube.

[0050] These techniques can be used alone or in any suitable combination. The foregoing is provided for purposes of illustration and is not intended to be limiting. BRIEF DESCRIPTION OF DRAWINGS

[0051] The drawings can not be to scale. In the drawings, each identical, or nearly identical, component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component is called out in every drawing. In the drawings:

[0052] Figure 1 is a perspective view of an electronic system including a cable coupler assembly configured to connect components with cables having different sizes in accordance with some embodiments.

[0053] Figure 2 is a top, side perspective view of a board connector that can be used in the electronic system of Figure 1

[0054] Figure 3 is a bottom, side perspective view of a cable connector for mating with the board connector of Figure 2

[0055] Figure 4 is a perspective view of a terminal assembly of the cable connector of Figure 3 Figure 2 is a top, side perspective view of the board connector of

[0056] Figure 5 is an exploded perspective view of a terminal assembly of the cable connector of Figure 3

[0057] is a perspective view of the cable coupler assembly of the electronic system of Figure 6 Figure 1 is a perspective view of the cable coupler assembly of the electronic system of​​​​

[0058] Figure 7 is a perspective view of a cable coupler of the cable coupler assembly of Figure 6

[0059] Figure 8 is a perspective view of a cable coupler of the cable coupler assembly of Figure 7

[0060] Figure 9 is a plan view of a cable coupler of the cable coupler assembly of Figure 8

[0061] Figure 10 is a perspective view of a cable assembly having a plurality of cable couplers arranged in an array Figure 7

[0062] Figure 11 is a simulated plot of S-parameters as a function of frequency of a signal transmitted through a cable coupler of Figure 7

[0063] Figure 12 is a plot of time domain reflectometry (TDR) impedance as a function of time as a signal is transmitted through a cable coupler of Figure 7 DETAILED DESCRIPTION

[0064] The present inventor has recognized and appreciated the technology for constructing high density electronic systems that provide high signal integrity at up to very high frequencies. The inventor has recognized and appreciated that high speed systems, such as systems capable of operating at 112 Gb / s or 224 Gb / s or higher, can benefit from using more cables to transmit signals that are conventionally transmitted via traces on printed circuit boards. However, more cable interconnections can require higher density cable interconnections. In addition, the inventor has recognized and appreciated that in cases where a large number of cables are terminated to a connector, the space occupied by cables that provide the desired signal integrity over long distances can limit how closely the terminals within the connector can be spaced. This in turn can limit the signal density of the cable assembly and the density of the electronic system using such a cable assembly.

[0065] ​​​​​​With the techniques described herein, small diameter cables can be terminated to cable connectors and can provide high density cable interconnections. The small diameter cables can have conductors that function as signal conductors of 28 AWG or smaller, such as 30 AWG or 32 AWG. These small diameter cables can be coupled to larger diameter cables, such as cables having conductors that function as signal conductors of 27 AWG or larger, such as 26 AWG or 24 AWG. Cable couplers as described herein can enable connections between the larger diameter cables and the small diameter cables without a significant impact on electrical performance. Exemplary embodiments can provide a return loss through the coupler of, for example, -20 dB or less. The small diameter cables can be connected in high density with connectors or other termination structures for cable assemblies, such as a pitch of 2.5 mm per signal pair, while the larger diameter cables can route signals over long distances, such as distances of 6 inches or more, without significant loss.

[0066] The inventors have recognized and appreciated the design of compact cable couplers for interconnecting cables of different gauges without introducing discontinuities in electrical performance along the signal transmission paths provided by the cables up to very high frequencies (e.g., 80 Ghz, or other frequencies for transmitting data at rates of 112 Gb / s or 224 Gb / s or higher). The couplers can be configured to support dense packaging so that multiple such cable couplers can be packaged in a cable connector assembly, providing a coupler that can be attached to multiple cables terminated to a high density connector.

[0067] A cable coupler can include one or more electrically conductive elements, such as a pair of electrically conductive elements configured to carry a pair of differential signals. Each electrically conductive element can have a first contact portion and a second contact portion disposed on opposite ends and configured to attach with cables of different gauges. The electrically conductive elements and surrounding structure of the cable coupler can be configured to provide little or no detectable change in impedance between a small diameter cable and a larger diameter cable. One or more techniques can be used to provide little or no change in impedance. These techniques can include different geometries of the electrically conductive elements at the first contact portion, the second contact portion, and an intermediate portion connecting the first contact portion and the second contact portion; maintaining an insulating housing of the electrically conductive elements with different effective dielectric constants in areas between and / or around the first contact portion, the second contact portion, and / or the intermediate portion; and applying a conductive layer over the housing so as to provide a desired separation from the electrically conductive elements adjacent the first contact portion, the second contact portion, and the intermediate portion.

[0068] In some embodiments, the first contact portions of the pair can be separated from one another by a first distance, which can be sized according to a first wire gauge (e.g., 32 AWG). The second contact portions of the pair can be separated from one another by a second distance, which can be sized according to a second wire gauge (e.g., 27 AWG). Each conductive element can have a wide side and an edge joining the wide side. The pair of conductive elements can be arranged to provide an impedance that matches an impedance of the cable. In the illustrated example, the conductive elements are in an edge-to-edge configuration, with an edge of one conductive element facing an edge of the other conductive element, separated by a distance and a material that provides a desired impedance.

[0069] A pair of wires of a first cable having a first wire gauge can be reliably attached at opposing surfaces of the first contact portions of the pair of conductive elements. In the illustrated example, the wires are attached to the edges of the contact portions. Similarly, a pair of wires of a second cable having a second wire gauge can be reliably attached at opposing edges of the second contact portions of the pair of conductive elements. With such an arrangement, changes in geometry at the cable attachment can be reduced, which can otherwise result in changes in impedance that can affect signal integrity. Alternatively or additionally, such an attachment interface can reduce the amount of metal at the attachment interface, thereby reducing changes in inductance relative to conventional designs in which cables are soldered to the wide sides of signal conductors, which also reduces changes in impedance.

[0070] A housing can hold the pair of conductive elements, including the cable attachments. The inventors have recognized and appreciated that the housing can be sized to fit within a space defined by the cables. In some examples, the first cables can be arranged in a first array; the second cables can be arranged in a second array; and the cable coupler can be arranged in a third array to interconnect the first array of first cables and the second array of second cables. The third array can be substantially similar in size to the larger of the first array and the second array, such that the cable coupler can fit into a limited space in a system.

[0071] The inventors have recognized and appreciated techniques for providing a high frequency cable coupler with a compact housing. The housing can be made primarily of a first material, and have a second material disposed at selected locations. The second material can have a lower dielectric constant than the dielectric constant of the first material. The locations and materials can be configured to provide an impedance that matches an impedance of other components of a system (e.g., 85 ohms, 95 ohms, 105 ohms) without expanding the size of the housing, and thus avoiding discontinuities that disrupt signal integrity along a signal transmission path. Impedances can be considered to be matched when they are the same or sufficiently close as to not have a significant impact on electrical characteristics along a signal path, such as within ±3% variation or less.

[0072] The housing can be formed of a dielectric material having a low dielectric constant, such as a relative dielectric constant less than 3. As a specific example, the dielectric constant can be, for example, 2.7. Within the housing, the cavities of the material can have different dielectric constants. The cavities can have a lower dielectric constant. As a specific example, the first cavity can be filled with air, which can have a dielectric constant of, for example, about 1. The first cavity can be disposed between the first contact portions of the pair of conductive elements. The second cavity is filled with air and disposed between the second contact portions of the pair of conductive elements. The first cavity can be at least partially bounded by the smaller of the first cable and the second cable, and the second cavity can be at least partially bounded by the larger of the first cable and the second cable. In some embodiments, the second cavity can have the same length as the first cavity in the signal transmission direction, but can be wider and / or deeper than the first cavity in other directions.

[0073] The cable coupler can have a conductive layer that electrically connects the shield layers of the connected cables. Such a conductive layer can partially or completely surround the housing of the coupled cables. In some examples, the conductive layer can be flexible and can conform to the sides of the housing, with two portions extending to the first cable and the second cable, respectively. In examples in which the conductive elements of the coupler are terminated by the conductive wires of the cables at opposite surfaces, such as opposite edges in an edge-coupling configuration, the spacing between the conductive structure carrying the signal and the outer conductive layer that is grounded within the cable coupler can be determined by the shape of the housing around the conductive elements. Such a configuration enables the signal-to-ground spacing to be controlled by the configuration of the housing. Since control of the signal-to-ground spacing controls variations in impedance, conforming the conductive layer to the housing enables precise control of impedance by the cable coupler.

[0074] Alternatively or additionally, portions of the conductive layer can conform to the perimeters of the first cable and the second cable, respectively. For example, two portions of the conductive layer can be electrically connected to the shield layers of the first cable and the second cable, respectively. Such a configuration can enable the cable coupler to make connections that have no appreciable effect on electrical characteristics along the signal transmission path up to very high frequencies, while meeting dimensional requirements according to the cable dimensions. The conformal conductive layer can be applied, for example, as a coating or as a heat shrink tube with an inner conductive layer that is passed around the cable coupler housing and a portion of each of the coupled cables, and then shrunk to conform to those structures.

[0075] The foregoing principles are illustrated in one example, such as Figure 1An electronic system 1 is shown. In the electronic system 1, a cable connection is made between a connector 20 mounted to a faceplate 4 at an edge of a printed circuit board 2 (e.g., a motherboard) and a connector 12A mounted on a printed circuit board 6 (e.g., a daughterboard). As shown, the daughterboard 6 can be mounted in a midboard region above the motherboard 2. The connector 12A can provide a low-loss path for routing electrical signals between one or more components mounted to the daughterboard 6, such as component 8, and a location away from the daughterboard 6. For example, the component 8 can be a processor or other integrated circuit chip. It will be appreciated that any suitable one or more components on the daughterboard 6 can receive or generate signals through the connector 12A.

[0076] In the example shown, the connector 12A couples signals to and from the component 8 through the connector 20 mounted to the faceplate 4 of the housing. The connector 20 can be an I / O connector that can mate with a transceiver that is terminated with an active optical cable assembly or an active electrical cable assembly that routes signals to or from another device. The faceplate 4 is shown as being orthogonal to the motherboard 2 and daughterboard 6. Such a configuration can occur in many types of electronic devices because high-speed signals are frequently routed through a faceplate of a housing that contains a printed circuit board, and must be coupled to high-speed components, such as processors or ASICS, that are further away from the faceplate than the distance that the high-speed signals can travel through the printed circuit board with acceptable attenuation. Connectors can be used to couple signals between locations inside the printed circuit board and one or more other locations inside or outside the housing.

[0077] In Figure 1 the example, the connector 12A mounted at an edge of the daughterboard 6 is configured to support a connection to the I / O connector 20. As can be seen, a cable connection can be made to other locations of the system. For example, there is a second connector 12B that makes a connection with the daughterboard 6.

[0078] The cables 14A and 14B can electrically connect the connectors 12A and 12B to locations that are further away from the component 8, or to locations that are further away from where the connectors 12A or 12B are attached to the daughterboard 6. In some embodiments, a first end 16 of the cables 14A and 14B can be connected to the connectors 12A or 12B, and a second end 18 of the cable 14A can be connected to the respective I / O connector 20. However, the connectors 20 can have any suitable functionality and / or configuration, as the present disclosure is not limited thereto. In some embodiments, higher frequency signals, such as signals higher than 112 Gbp, such as 224 Gbp or higher in some examples, can be connected through the cables 14A or 14B, which can otherwise be susceptible to signal loss at distances greater than or equal to 6 inches.

[0079] Cable 14A can have a length that enables connector 12A to be spaced apart from second end 18 at connector 20 by a first distance. In some embodiments, the first distance can be longer than a second distance over which signals at frequencies passing through cable 14A can propagate along traces within motherboard 2 and daughterboard 6 with acceptable loss. In some embodiments, the first distance can be at least 6 inches, in a range of 1 to 20 inches, or any value within the range, such as between 6 and 20 inches. However, the upper limit of the range can depend on the size of motherboard 2 or an electronic system incorporating motherboard 2.

[0080] In some examples, connections can be needed between locations spaced apart by a distance longer than the first distance over which signals can pass through cable 14A sized to terminate to connectors 12A and 12B without a significant impact on electrical performance. Such connections can be made with cables having a larger diameter than the diameter of cables extending from cable connectors (e.g., cables 14A, 14B) so that high-density cable connectors can be used to fit many cables within the limited space near an electronic component (e.g., daughterboard 6) while larger cables can be used to route signals over longer distances without causing significant loss. The smaller cables can be connected to the larger cables through cable couplers that can be configured to introduce no significant discontinuity in electrical characteristics up to very high frequencies (e.g., 80 GHz) along the signal transmission path provided by the cables while meeting size requirements according to the cable size. As a specific example, a cable coupler can provide an insertion loss of less than -20 dB between a large diameter cable and a small diameter cable over a frequency range of 0 to 80 GHz and have physical dimensions suitable for a spacing of between 1 mm and 2.5 mm. In the illustrated example, cable 14B can have a first end 16 attached to connector 12B and a second end 18 attached to cable assembly 600 (see Figure 6 ) at connector 20.

[0081] In some examples, connector 12A can be configured to mate to daughterboard 6 or another PCB to enable easy routing of signals coupled through the connector. For example, an array of signal pads that mate with terminals of connector 12A can be spaced apart from an edge of daughterboard 6 or another PCB so that traces can be routed out of that portion of the footprint in all directions, such as toward component 8.

[0082] As shown, the connector 12A can include cables 14A arranged in multiple rows at the first end 16 and extending out of the connector 12A. Such a configuration, or another suitable configuration selected for the connector 12A, can result in a relatively short breakout area that maintains signal integrity when connecting to adjacent components, as compared to routing patterns that can be required to route out the same signals from an array having more rows and fewer columns.

[0083] As Figure 1 shown, the connector 12A can fit within a space within the electronic device 1 that can otherwise not be usable. In this example, a heat sink 10 is attached to the top of a processor or component 8. The heat sink 10 can extend beyond the perimeter of the processor 8. When the heat sink 10 is mounted over the sub-board 6, there is a space between the heat sink 10 and portions of the sub-board 6. However, this space has a height H that can be relatively small, such as 5 mm or less, and a conventional connector can not fit within this space or can not have enough clearance to mate. However, at least a portion of the connector 12A and other connectors of the example embodiments described herein can fit within this space adjacent to the processor 8. For example, the thickness of the connector housing can be between 3.5 mm and 4.5 mm. Such a configuration uses less space on the printed circuit sub-board 6 as compared to a case where the connector is mounted to the printed circuit sub-board 6 outside of the perimeter of the heat sink 10. Such a configuration enables more electronic components to be mounted to the printed circuit to which the mid-board connector (e.g., the connector 12A) is connected, thereby increasing the functionality of the electronic device 1. Alternatively, the printed circuit board, such as the sub-board 6, can be made smaller, thereby reducing its cost. Further, the integrity of the signals passing from the connector 12A to the processor 8 can be increased as compared to an electronic device in which a conventional connector is used to terminate the cables 14A, as the length of the signal path through the printed circuit sub-board 6 is reduced.

[0084] While Figure 1 embodiments depict connectors that connect to a daughter card at a mid-board location, it should be noted that the connector assemblies of the example embodiments described herein can be used to make connections with other substrates and / or other locations within an electronic device.

[0085] As discussed herein, midboard connector assemblies can be used to make connections with processors or other electronic components. These components can be mounted to a printed circuit board or other substrate to which the midboard connector can be attached. These components can be implemented as integrated circuits, for example having one or more processors in an integrated circuit package, including commercially available integrated circuits such as those known in the art by the names CPU chip, GPU chip, microprocessor, microcontroller, or co-processor. Alternatively, the processors can be implemented in custom circuits such as ASICs or semi-custom circuits generated from configured programmable logic devices. As yet another alternative, the processors can be part of a larger circuit or semiconductor device, whether commercially available, semi-custom, or custom. As a specific example, some commercially available microprocessors have multiple cores in one package, such that one core or subset of the cores can constitute a processor. Such processors can handle a large number of signals, such as more than 1000 or more than 2000 signals, such that creating a compact electronic system can benefit from high-density connections through connectors such as connectors 12A and 12B. However, the processors can be implemented using any suitable format of circuitry.

[0086] In the illustrated embodiment, the processors are shown as components that are separately attached to the package of the daughter card 6, such as by surface mount soldering. In such cases, the daughter card 6 serves as the substrate on which the connectors 12A are mounted. In some embodiments, the connectors can be mated to other substrates. For example, semiconductor devices such as processors are often fabricated on substrates such as semiconductor wafers. Alternatively, one or more semiconductor chips can be attached to a wiring board, which can be a multilayer ceramic, resin, or composite structure, for example in a flip chip bonding process. The wiring board can serve as the substrate on which the connectors are mounted.

[0087] The connectors 12A and / or 12B can be implemented by mating a board connector that can be mounted to the daughter board 6 with a cable connector that can have cables extending therefrom, for example cables 14A, 14B.

[0088] Figure 2 is a perspective view of an exemplary board connector 100. As shown, the board connector can comprise a single piece of material (e.g., metal) and can be formed at least in part by stamping and overmolding. As shown, the board connector 100 includes a terminal assembly comprising a base 101 and two wing portions 102. The base 101 is disposed in a first plane, while the two wing portions 102 extend from the base 101. In the illustrated embodiment, the wing portions 102 extend orthogonally from the base 101. Figure 2

[0089] ​The board connector may include features for engaging and positioning cable connectors. In the example shown, these features include a plurality of protruding receivers 104, with two protruding receivers 104 disposed on each wing 102 near the corner region of the wing. Each wing 102 also includes a guide channel 106, which is inclined relative to a base 101 and has an open end opposite to the base 101. The guide channel 106 may be angled relative to the base 101. In some embodiments, this angle may be between 15 degrees and 60 degrees, or between 30 degrees and 55 degrees. For example, Figure 2 A guide channel 106 is shown at an angle of approximately 45 degrees relative to the base.

[0090] Each wing may include two introduction tabs 108 associated with the protruding receiver 104. (See reference...) Figure 4 The functions of the introduced tab 108 and protrusion receiving portion 104 are further discussed. According to some embodiments, such as... Figure 2 As shown, the board connector may include alignment protrusions 118 configured to assist in aligning the board connector terminals with contact pads on a PCB or other substrate. The alignment protrusions 118 may be received in corresponding holes in the PCB or other substrate to orient and align the board connector. For example, the protrusions 118 can be used to position the board connector on the PCB before reflow soldering the terminals of the board connector to the pads on the PCB.

[0091] The board connector 100 may include a plurality of terminals 112 associated with a base 101. The plurality of terminals 112 may be integrally formed with the base 101 during a manufacturing process in which the terminals 112 are stamped from sheet metal. In the illustrated example, the terminals 112 are arranged in four rows. Each row may be configured to mate with a terminal subassembly of a mating cable connector.

[0092] Each terminal 112 may include a first portion 114 and a second portion 116. The first portion 114 may be disposed in the plane of the base 101 and may include a tail configured for surface mounting to an associated substrate (e.g., a PCB). For example, the tails may each be configured to be soldered to the PCB using a solder reflow process. The second portion 116 may be disposed at an angle relative to the plane of the base 101. The second portion 116 may extend upward away from the base 101 to form a contact tip for a corresponding terminal of a cable connector. The second portion 116 may serve as cantilever beams configured to undergo elastic bending and provide a bias spring force when the cable connector mates with the board connector 100, the bias spring force causing the corresponding cable connector to move away from the board connector. In some embodiments, the second portion 116 may be at an angle, for example, between 15 and 45 degrees, relative to the plane below the base 101. Figure 2In the example shown, the angle of the second portion 116 is between 20 and 30 degrees.

[0093] The board connector 100 can include a dielectric 110 overmolded on the plurality of terminals 112 and the base 101. The dielectric can be configured to physically support each of the terminals 112 relative to the base 101. Thus, the plurality of terminals 112, which are integrally formed, can be physically and electrically separated from one another. In some embodiments, the tie bars between the terminals 112 can be removed. Once the plurality of terminals 112 are electrically severed, the dielectric 110 can provide a unique physical support for the terminals 112 and can maintain their position relative to the base 101. Thus, in some embodiments of the manufacturing process, the terminal assemblies can be stamped, the dielectric 110 can be overmolded over the plurality of terminals 112 and a portion of the base 101, and at least a portion of the terminals 112 can be electrically severed from one another (e.g., by removing the tie bars). Although each terminal assembly includes 76 terminals in the example shown, it should be understood that any number of terminals can be employed as the present disclosure is not so limited.

[0094] Figure 3 is a perspective view of an example embodiment of a cable connector 200. The cable connector 200 can include a connector housing 202. The connector housing 202 can include a plurality of protrusions 204. In particular, the connector housing 202 can have Figure 3 two protrusions 204 shown, and two corresponding protrusions 204 on opposite sides of the connector housing 202. The protrusions 204 can be configured to engage protrusion receivers (e.g., the protrusion receivers 104) formed in a board connector (e.g., the board connector 100). The protrusions 204 can be configured to engage the protrusion receivers 104 to resist movement of the cable connector 200 away from the board connector 100. Each of the protrusions 204 can include an introduction portion 206 configured to enable the protrusion 204 to move past the corresponding protrusion receiver 104 as the cable connector is moved toward the board connector, as will be discussed further with reference to Figure 4 FIG. 3.

[0095] The connector housing 202 can include guides 208 disposed on opposite sides of the connector housing 202. The guides 208 can be angled relative to a bottom face 218 of the connector housing 202, which can be placed parallel to a PCB or other substrate when the cable connector 200 is engaged with the board connector 100. The guides 208 can be angled relative to the bottom face 218 at an angle. The guides 208 can be angled at an angle that matches the angle of the guide channels 106. The angle can be, for example, between 15 degrees and 60 degrees, such as an angle between 30 degrees and 50 degrees. The guides 208 can be received in the corresponding guide channels 106 of the board connector 100 to limit the relative movement of the cable connector 200 to a single axis (i.e., eliminating or reducing rotational axes). The connector housing 202 can be formed of a dielectric material (e.g., plastic), although the present disclosure is not limited in this regard and can employ any suitable material.

[0096] The connector housing 202 can be configured to receive a plurality of terminal assemblies 212. The terminal assemblies 212 can be received in slots arranged in a row such that the plurality of terminals 214 can extend at an angle relative to the bottom face 218. As shown, the terminal assemblies 212 can be angled relative to the bottom face 218 at an angle. The terminal assemblies 212 can be angled at an angle that matches the angle of the guides 208. The angle can be, for example, between 15 degrees and 60 degrees, such as an angle between 30 degrees and 50 degrees. The terminal assemblies 212 can be configured to be retained in the connector housing 202 with retention tabs 304 (shown in FIG. 3) that engage corresponding tab receiving portions 210 formed in the connector housing 202. Each terminal assembly 212 can include a member 216 configured to connect ground terminals to reduce resonance patterns. Although each terminal assembly includes 19 terminals, and the connector housing accommodates four terminal assemblies, for a total of 76 terminals in the illustrated example, it should be understood that any number of terminals and terminal assemblies can be employed, as the present disclosure is not limited in this regard. Figure 5

[0097] Figure 4 is a perspective view showing the board connector 100 mated with the cable connector 200. As shown, the guides 208 of the cable connector housing 202 can be received in the guide channels 106 of the first and second wings 102 of the board connector 100. Thus, movement of the cable connector 200 can be limited to movement along a single axis, with movement in a first direction causing the cable connector 200 to move closer to the board connector 100, and movement in a second direction causing the cable connector 200 to move further away from the board connector 100. The axis of movement of the cable connector 200 can be parallel to the guides 208 and the guide channels 106, and in the illustrated example, between 30 degrees and 45 degrees relative to the base 101 of the board connector 100.​

[0098] The lead-in portion 206 of each protrusion 204 of the cable connector 200 can align with the lead-in tab 108 of the board connector 100. The lead-in portion 206 and the lead-in tab 108 can have complementary angled surfaces such that engagement between the lead-in portion 206 and the lead-in tab 108 does not inhibit movement of the cable connector. When the lead-in portion 206 engages the lead-in tab 108, the first and second wings 102 of the board connector 100 can elastically deform outward away from the cable connector 200 such that the wings 102 of the board connector 100 can accommodate the width of the cable connector 200.

[0099] As the cable connector 200 continues to move closer to the board connector 100, the lead-in portion 206 can engage the protrusion receiving portion 104 to deform the wings 102 outward and avoid capturing the protrusions 204 in the protrusion receiving portion 104 when the cable connector 200 moves in the first direction. Thus, the cable connector 200 can move freely in the first direction until the terminals 214 of the cable connector 200 contact the terminals 112 of the board connector 100.

[0100] Upon insertion of the cable connector 200 into the board connector 100, the terminals of the cable connector 200 can engage the second portions 116 of the terminals 112 of the board connector 100. As the second portions 116 can be disposed at an angle relative to the base 101, the second portions can elastically deform and create a biasing force that pushes the cable connector 200 away from the board connector 100 in the second direction. Thus, when the insertion force is reduced or removed from the cable connector 200, the cable connector can move in the second direction under the push from the second portions 116 until the protrusions 204 are captured in the protrusion receiving portion 104, thereby inhibiting further movement in the second direction. This process can enable a terminal wipe for efficient electrical conduction and provide a small variation in stub length for the terminals.

[0101] Figure 5is an exploded perspective view of an exemplary embodiment of a cable connector terminal assembly 212. The terminal assembly 212 can include a plurality of terminals 214 extending from a cable clamp plate 300. The plurality of terminals 214 and the cable clamp plate 300 can be stamped from the same piece of metal such that the plurality of terminals and the cable clamp plate are integral at a point. As shown, the terminal assembly 212 can include a dielectric 306 overmolded over the plurality of terminals 214 and a portion of the cable clamp plate 300. The dielectric 306 can be a plastic material. The dielectric 306 can physically support the plurality of terminals 214. Accordingly, at least a portion of the plurality of terminals 214 can be physically separated (e.g., tie bars removed) from the cable clamp plate 300 to electrically isolate the terminals. The dielectric 306 can be configured to maintain the relative positions of the terminals 214. The cable clamp plate 300 can include a retention tab 304 configured to be received in a corresponding tab receptacle 210 of a cable connector housing 202. Such an arrangement allows the terminal assembly to be securely and accurately fixed in the cable connector housing.

[0102] The cable clamp plate 300 can be configured to secure a plurality of cables 310 to the terminal assembly 212. In the example shown, the cables 310 are configured as quadaxial cables. The techniques as described herein enable the quadaxial cables to be spaced apart at a relatively small pitch, such as a center-to-center pitch of between 1 mm and 2.5 mm or between 1.5 mm and 2.5 mm, such as between 2.3 mm and 2.5 mm or 2.4 mm in some examples. Each cable 310 can include two cable conductors 318, each of which can be electrically and physically coupled to one or more terminals 214. Each of the cable conductors 318 can be surrounded by a dielectric insulation 316, which can electrically insulate the cable conductors from one another. A shield layer 314, which can be grounded, can surround the cable conductors 318 and the dielectric insulation 316. The shield layer 314 can be formed from a metal foil. The shield layer 314 can extend along a perimeter of the dielectric insulation 316. The shield layer 314 can be coupled to one or more contact tips of a grounded terminal of the terminal 214 by a flexible conductive member (e.g., member 308). Surrounding the shield layer can be an insulating jacket 312. Although quadaxial cables are shown in Figure 5

[0103] ​The conductors 318 of the cable 310 can be attached to the tails of the terminals 214 in the terminal assembly 212, for example, by brazing or soldering. The shield 314 of the cable can be electrically connected to the ground structure of the terminal assembly 212 by clamping.

[0104] The cable clamp plate 300 can include a plurality of strain relief portions 302. In the illustrated example, the strain relief portions 302 are defined by I-shaped slots or openings formed in the cable clamp plate 300, which can enable the cable clamp plate 300 to deform under the clamping pressure that secures the cable 310 to the cable clamp plate 300. Such an arrangement can reduce or eliminate the likelihood that the cable conductors 318 are crushed or altered by the clamping force. In the illustrated example, the members 308 are configured to clamp the cable 310 to the cable clamp plate 300. Once an appropriate clamping force (e.g., 100 pounds) is applied to the metal plate, the members 308 can be secured around the cable 310 by welding (e.g., laser welding), overmolding, or another appropriate process.

[0105] The terminal assembly can include a member 216 configured to electrically interconnect the ground terminals of the terminals 214. The member 216 can be laser welded or soldered to the ground terminals of the terminals 214 near the ends of the terminals 214. For example, the ground conductors can be no more than 1.97 mm from the ends of the terminals 214. Such an arrangement can reduce the quarter wavelength of the standing wave resonance mode, enabling the cable connector 200 to support higher frequencies without resonance mode interference.

[0106] Figure 6 is a perspective view of a cable assembly 600 of the electronic system 1. The cable assembly 600 can include a plurality of cable couplers 700 arranged in multiple rows. Each cable coupler 700 can interconnect a first cable 710 having a smaller gauge to a second cable 720 having a larger gauge, the first cable 710 can extend out of a high-density connector such as the connector 12B or the cable connector 200, the second cable 720 can transmit signals over a longer distance with less loss than the first cable 710. The first cables 710 can be arranged in a first array; the second cables 720 can be arranged in a second array; and the cable couplers 700 can be arranged in a third array to interconnect the first array of first cables 710 and the second array of second cables 720. The third array can be substantially similar in size to the second array, such that the cable couplers 700 can fit into limited space in the system. For example, when the first cables 710 and the second cables 720 have 32 AWG and 27 AWG, respectively, a center-to-center distance pi between two adjacent cable couplers 700 within a row can be no more than 2.4 mm, and a center-to-center distance p2 between two adjacent couplers 700 aligned in adjacent rows can be no more than 2.0 mm. Although in the illustrated example the cable couplers 700 are arranged in two rows, the cable couplers 700 can be arranged in more than two rows. Figure 6Two rows of cable couplings 700 are shown in FIG. 8, with four cable couplings 700 in each row, but it should be understood that the cable assembly 600 can include an array of cable couplings 700 arranged according to the arrangement of corresponding connectors, such as the connector 12B or the cable connector 200.

[0107] Although Figure 6 The segments of the first cables shown in FIG. 8 extend in parallel from the cable couplings 700, but those cables can bend together as they approach the connector. Thus, at the cable connector that terminates the cables 710, the spacing between the cables can be less than the spacing between the cable couplings.

[0108] The cable couplings 700 are configured to fit in a space limited by the dimensions of the cables, while having no significant impact on the electrical characteristics along the signal transmission path up to very high frequencies. Figure 7 and Figure 8 A perspective view of the cable couplings 700 is shown in FIG. 9. Figure 9 is a plan view of the cable couplings 700. In this example, the cable couplings are configured to couple two unshielded twisted pair cables having different wire gauges. As shown, the cable couplings 700 can include a pair of conductive elements 832A and 832B, a housing 840 that holds the pair of conductive elements 832A and 832B, and a conductive layer 730 that is conformally applied to the surface of the housing 840 and / or the ends of the first and second cables 710 and 720. The conformal conductive layer can conform to the ends of the exposed cable shield layers of the cables to be coupled, such that the conformal conductive layer 730 provides a continuous ground path from one cable shield layer to the other.

[0109] The pair of conductive elements 832A and 832B can be configured to interconnect the wires of the first cable 710 having a smaller wire gauge to the wires of the second cable 720 having a larger wire gauge. Each conductive element 832A or 832B can include a first contact portion 902, a second contact portion 904 opposite the first contact portion, and an intermediate portion 906 between the first contact portion 902 and the second contact portion 904.

[0110] The conductive elements can be stamped and can optionally be formed into a configuration for terminating the wires of the first and second conductors with low impedance discontinuities. In this illustrated example, the conductive elements are made of a highly conductive metal such as a copper alloy. The conductive elements are generally planar, such as can be produced by stamping the conductive elements from a sheet of metal. To provide a controlled impedance within the cable coupler, spacing between the conductive elements can be established by stamping. For example, the spacing can be initially maintained by stamping one or more tie bars from the sheet of metal at the same time as the conductive elements. The conductive elements can be secured with a housing that can be overmolded onto the conductive elements, after which the tie bars can be severed. In the illustrated example, the wires of the cable are attached to the edges of the conductive elements, enabling the entire conductive elements to be manufactured without any folding or other shaping operations that can result in imprecise positioning of features of the conductive elements.

[0111] The conductive elements can also be made with a configuration that facilitates cable connection with very little impedance variation along the length of the conductive elements, even at frequencies up to 80 Ghz. As Figure 9 As shown in the example of FIG. 9, the first contact portion 902 can have a first notch 922 having a first width r1 configured to have a first wire of the first cable 710 having a first diameter D1 attached thereto. The second contact portion 904 can have a second notch 924 having a second width r2 configured to have a second wire of the second cable 720 having a second diameter D2 attached thereto. As shown, the first width r1 can be substantially similar to the first diameter D1; and the second width r2 can be substantially similar to the second diameter D2.

[0112] Each conductive element 832A or 832B can have a wide side 804 and an edge 802 joining the wide side 804. The first contact portions 902 can have first edges 912 facing one another. The second contact portions 904 can have second edges 914 facing one another. The intermediate portions 906 can have third edges 916 facing one another. The first edges 912 can be offset from the respective third edges 916 by a first width r1 of the first notches 922. The second edges 914 can be offset from the respective third edges 916 by a second width r2 of the second notches 924. As shown, the first cable 710 can have a first pair of wires 812A and 812B each having a first mounting end 910 attached at a respective first notch 922 to a first edge 912 of a respective first contact portion 902. The second cable 720 can have a second pair of wires 822A and 822B each having a second mounting end 920 attached at a respective second notch 924 to a second edge 914 of a respective second contact portion 904.

[0113] For a pair of conductive elements 832A and 832B, as shown, the first contact portions 902 can be separated from one another by a first distance d1. Each conductive element 832A or 832B can have a transition portion 908 between the respective intermediate portion 906 and the second contact portion 904. The transition portions 908 of the pair can be staggered from one another such that the second contact portions 904 can be separated from one another by a second distance d2 that is greater than the first distance d1. The intermediate portions 906 can be separated from one another by a third distance d3 that is less than the first distance d1. The outer edges of the first contact portions 902 can be separated from one another by a fourth distance d4 that is configured to be substantially similar to the size of the first cable 710. The outer edges of the second contact portions 904 can be separated from one another by a fifth distance d5 that is configured to be substantially similar to the size of the second cable 720. Figure 9

[0114] The pair of conductive elements 832A and 832B can be made of a metal or any other material that is electrically conductive and provides suitable mechanical properties for the conductive elements in the electrical connector. Phosphor bronze, beryllium copper, and other copper alloys are non-limiting examples of materials that can be used. The conductive elements can be formed from such materials in any suitable manner, including by stamping and / or forming.

[0115] While a pair of conductive elements configured for a cable having a pair of wires is shown, it should be understood that the cable coupler can have any suitable number of conductive elements configured to have a respective cable attached thereto. For example, the cable coupler can have one conductive element for a single-ended cable, two or more pairs of conductive elements for a cable having multiple pairs of wires, etc.

[0116] Referring to​Figure 8 and Figure 9 The housing 840 can be molded from one or more dielectric materials. The housing 840 can include a first material 842 having a first dielectric constant and a second material 844 having a second dielectric constant, which can be less than the first dielectric constant. The second material 844 can be selectively disposed between the pair of conductive elements 832A and 832B in order to balance the impedance along the transmission path. Without the second material 844, the pair of conductive elements 832A and 832B would need to be separated further from one another to provide the desired impedance, which can make the cable coupler too large to fit in a space limited by the dimensions of the cable. Examples of suitable first materials include, but are not limited to, liquid crystal polymer (LCP), polyphenylene sulfide (PPS), high-temperature nylon, or polyphenylene oxide (PPO), or polypropylene (PP). In some examples, a material having a relative dielectric constant of 3 or less can be used. Examples of suitable second materials include air and any suitable material having a desired dielectric constant, which can be less than the dielectric constant of the rest of the housing.

[0117] The second material 844 can be disposed between the first mounting end 910 of the first cable 910 and / or the second mounting end 920 of the second cable 920. As shown, the housing 840 can have a first cavity 812 disposed between the first mounting end 910 of the first cable 910 and a second cavity 814 disposed between the second mounting end 920 of the second cable 920. Although the first cavity 812 and the second cavity 814 are described as being filled with the same second material 844, it should be understood that the first cavity 812 and the second cavity 814 can be filled with different materials having a dielectric constant that is less than the first dielectric constant of the first material 842. Furthermore, while the rest of the housing is shown as a unitary material, in some examples, the housing in the areas adjacent to the first and / or second contact portions and / or the middle portion can be different to match the impedance in each portion.

[0118] The first cavity 812 and the second cavity 814 can be shaped and sized to provide a desired impedance along the signal transmission path through the cable coupler. As shown, the first cavity 812 can have a first length li, a first width wi, and a first thickness ti. The second cavity 814 can have a second length 12, a second width w2, and a second thickness t2. In some embodiments, the second length 12 can be equal to the first length li. The first length li can be in the range of 0.5 mm to 2 mm. The second width w2 can be greater than the first width wi. The second thickness t2 can be greater than the first thickness ti. As shown, each of the first cavity 812 and the second cavity 814 can be a cuboid shape.

[0119] In some embodiments, the shell 840 can have a first portion 842 that encloses the first contact portions 902 of the pair of conductive elements 832A and 832B and the first mounting end 910 of the first cable 710, and a second portion 844 that encloses the second contact portions 904 of the pair of conductive elements 832A and 832B and the second mounting end 920 of the second cable 720.

[0120] Referring to Figure 7 , the conductive layer 730 can be conformally applied over the shell 840 and / or the ends of the first cable 710 and the second cable 720. The conformal application of the conductive layer enables the distribution of the shell in each portion of the cable connector to establish a separation between the signal conductors and the ground layer within the cable coupler, which is a parameter that controls the impedance. To provide uniformity of the impedance along the length of the cable coupler, the shell can have different outer perimeters in different portions. As shown, for example, in Figure 9 , the perimeter of the shell is larger around the second contact portions 904 than around the first contact portions. In this example, the outer perimeter around the intermediate portion 906 is the same as the outer perimeter around the first contact portions. However, in other examples, the perimeter of the shell can be different around each portion. Also as shown in Figure 9 , the variations in the outer surface of the shell follow the variations in the outer edges of the conductive elements. As with the distance from the centerline of the cable coupler to the outer edge of each conductor, the distance from the centerline to the outer surface of the shell varies similarly. To provide a generally uniform spacing between the outer edges of the conductive elements and the surface of the shell, there can be tapered regions at the transitions between the portions of the conductive elements, such as the tapered regions 950, 952, or 954.

[0121] As shown, the conductive layer 730 can have a first portion 732 conformally applied over the shell 840, a second portion 734 conformally applied over the end of the first cable 710, and a third portion 736 conformally applied over the end of the second cable 720. The second portion 734 can be conformal with the perimeter of the first cable 710 at which the cable shield has been exposed by removing a length of the cable jacket in order to electrically connect to the shield of the first cable 710 (e.g., the shield 314 in Figure 5 ). The third portion 736 can be conformal with the perimeter of the second cable 720 at which the shield of the cable has been exposed in order to electrically connect to the shield of the second cable 720.

[0122] One or more parameters of the cable coupler can be selected in each portion of the cable coupler (e.g., the first contact portion, the second contact portion, and the intermediate portion) to provide a desired impedance in each portion. In some examples, the impedance can be within + / - 3% or + / - 2% or + / - 1% of 95 ohms or 85 ohms, 100 ohms or 120 ohms, for example. Parameters that can be selected to achieve the desired impedance in each portion can include: the size of the conductive elements, including Figure 9 the size of the conductive elements shown in FIG. 6 and / or the width of the conductive elements in the plane shown in Figure 9 FIG. 6 and / or the thickness of the conductive elements perpendicular to the plane shown in Figure 9 FIG. 6, the thickness of the housing around the conductive elements (which sets the spacing of the ground, applied as a conformal layer on the outside of the housing), and / or the dielectric constant of the housing in each portion, including any windows therein, which can be filled with air or other material having a different dielectric constant than the rest of the housing.

[0123] A method of interconnecting a first cable 710 and a second cable 720 can include providing a pair of conductive elements 832A and 832B, forming a housing 840 to at least partially enclose the pair of conductive elements 832A and 832B, and applying a conductive layer 730 over the housing 840, e.g., by a heat shrink tube or PVD or other plating or coating technique. For application by a heat shrink tube, a tube having a conductive inner coating and / or made of a conductive material can be threaded over one of the cables. After the cable and optional second cable are terminated to the contact portions of the cable coupler and the housing of the cable coupler is applied, the tube can be slid over the housing while partially overlapping one or both of the cable ends. Heat can then be applied to heat the tube. An example of a heat shrink tube is a CHO-SHRINK conductive heat shrink tube available from Parker Hannifin.

[0124] In some embodiments, multiple cable couplers 700 can be grouped together. The cable couplers of the group can be connected to each other or can be held by a common support member so as to form a cable coupler assembly. In the example shown, the support member is molded over the group. The overmolded support member can additionally provide strain relief for the cables of the assembly. Figure 10 A perspective view of such a cable assembly 1000 having multiple cable couplers 700 arranged in an array is shown, with a support member 1002 shown in perspective.

[0125] Figure 11is a plot of the S-parameters as a function of the frequency of the signal transmitted through the cable coupler 700. As shown, the insertion loss 1102, which can indicate the ratio of the input power to the transmitted power, remains linear and close to 0 dB up to 65 Ghz. The return loss 1104, which can indicate the ratio of the amount of signal power injected from the source that is returned or reflected back toward the source, remains below -20 dB up to 65 Ghz. These results indicate that the cable coupler 700 is able to provide high signal integrity up to very high frequencies.

[0126] Figure 12 is a plot of the time domain reflectometry (TDR) impedance as a function of time as a signal is transmitted through the cable coupler 700. As shown, the TDR impedance, which can indicate discontinuities along the transmission line, is substantially uniform over time, which indicates that the impedance changes vary with distance through the cable coupler. In this example, the impedance changes are less than about + / - 2 ohms, which is about + / - 2% along the length of the cable coupler. This plot further indicates that the cable coupler 700 has no appreciable effect on the electrical characteristics along the signal transmission path over time.

[0127] Accordingly, several aspects of cable assemblies have been described, it is to be understood that various alterations, modifications, and improvements will readily occur to those skilled in the art.

[0128] For example, the coupler is illustrated with a pair of conductive elements in an edge-to-edge configuration. It should be understood that the pair of conductive elements can be wide-side coupled over a portion or all of the length of the conductive elements. For example, a middle portion 906 of the pair of conductive elements can be wide-side coupled, which can provide the desired coupling between the pair of conductive elements.

[0129] As another example, the illustrated cable coupler is configured to provide a uniform impedance, which can be suitable for coupling two cables having the same impedance. In other examples, the coupled cables can have different impedances, and the middle portion of the cable coupler can provide a smooth impedance transition by varying one or more of the characteristics described herein along the length of the middle portion.

[0130] As yet another example, the cable connector is illustrated in connection with a particular configuration of a board connector and a cable connector. The cable coupler as described herein can be used with other configurations of connectors, or in some examples, without any connectors. In some examples, the cable assembly can be formed with a press-fit connector that terminates a plurality of cables. The press-fit connector can mate with a board by pressing the contacts of the connector against pads of the board without using a separate board connector.

[0131] Further, cable coupler assemblies are described in which multiple cable couplers are held together in a rectangular array. The cable couplers can be positioned in other configured arrays. As one example, the cable couplers can be arranged in multiple rows with adjacent rows offset in a row direction. Optionally, some or all of the cable couplers can be used without being assembled into an assembly.

[0132] Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the present utility. Although the present teachings have been described in connection with various embodiments and examples, it will be understood that the teachings are capable of further modifications. Therefore, this application is intended to cover any variations, uses, or adaptations of the application including such departures from the present teachings as come within known or customary practice in the art.

[0133] Moreover, the described techniques can be embodied as a method, of which at least one example has been provided. The acts performed as part of the method can be ordered in any suitable way. Accordingly, embodiments can be constructed in which acts are performed in an order different than illustrated, which can include performing some acts simultaneously, even though shown as serial acts in illustrative embodiments.

[0134] All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and / or ordinary meanings of the defined terms.

[0135] Numerical values and ranges can be described in the specification and claims as approximations or in precise terms or ranges. For example, in some instances, the terms "about," "approximately," and "substantially” can be used to refer to values. Such references are intended to include reference values and reasonable variations thereof. For example, the phrase "between about 10 and about 20" is intended to mean "between exactly 10 and exactly 20" in some embodiments, and is intended to mean "between 10 ± dl and 20 ± d2" in some embodiments. In some embodiments, the amount of variation dl, d2 of a value can be less than 5% of the value, in some embodiments less than 10% of the value, and in some embodiments less than 20% of the value. In embodiments where a large range of values is given (e.g., a range including two or more orders of magnitude), the amount of variation dl, d2 of a value can be up to 50%. For example, if a range of operable values extends from 2 to 200, then "about 80" can include values between 40 and 120, and the range can be as large as between 1 and 300. The term "exactly" is used when only an exact value is desired, e.g., "between exactly 2 and exactly 200." The term "substantially" is used to indicate a value is the same or within ±3% of a target value or condition.

[0136] The term“adjacent” can refer to two elements being arranged in proximity to one another (e.g., within a distance that is less than about 1 / 5th the transverse or vertical dimension of the larger of the two elements). In some cases, intervening structures or layers can be present between adjacent elements. In some cases, adjacent elements can be directly adjacent to one another without intervening structures or elements.

[0137] The indefinite articles“a” and“an,” as used in the specification and in claims, unless clearly indicated to the contrary, should be understood to mean“at least one.”

[0138] The phrase“and / or,” as used herein in the specification and in claims, should be understood to mean“either or both of” the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with“and / or” should be construed in the same fashion, i.e.,“one or more” of the elements so conjoined. Other elements can optionally be present other than the elements specifically identified by the“and / or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to“A and / or B” when used in the

[0139] As used in the specification and claims, “or” should be understood to have the same meaning as“and / or” as defined above. For example, when used in a list of items, “or” or“and / or” should be interpreted as

[0140] As used in the specification and claims, the phrase “at least one,” with respect to a list of one or more elements, should be understood to mean at least one of the elements, but not necessarily including more than one of each element, i.e., “at least one” specifically implies “one or more of even the same element is allowable under the terms “at least one.” Further, when used in the context of “or” as used herein, e.g., “A or B” or “A and / or B,” the phrase is intended to mean “at least one of A or at least one of B.” Also, to the extent that any definition or usage of a term herein is inconsistent with the usage of that term in the remaining portions of this document, the usage in this section shall prevail.

[0141] In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of’ and “consisting essentially of’ shall be closed or semi-closed transitional phrases, respectively.

[0142] The claims should not be read to be limited to the described order or elements unless such order or elements are explicitly recited in the claims. It should be understood that various changes in form and detail can be made to the embodiments described herein without departing from the spirit and scope of the claims. All embodiments are intended to be within the scope of the claims and their equivalents.

Claims

1. A cable coupler, characterized by, comprise a first contact portion, a second contact portion opposite the first contact portion, and an intermediate portion between the first contact portion and the second contact portion; a cable comprising a pair of wires, each wire of the pair of wires comprising a mounting end disposed between the pair of electrically conductive elements and attached to the first contact portion of a respective electrically conductive element of the pair of electrically conductive elements; and a housing holding the pair of electrically conductive elements, the housing comprising a first material having a first dielectric constant and a second material disposed between the mounting ends of the pair of wires of the cable, the second material having a second dielectric constant less than the first dielectric constant. comprise a first contact portion, a second contact portion opposite the first contact portion, and an intermediate portion between the first contact portion and the second contact portion, the first contact portion comprising a first notch having a first width configured to have a first wire having a first diameter attached thereto, the second contact portion comprising a second notch having a second width configured to have a second wire having a second diameter attached thereto, the second diameter being different than the first diameter; and a housing holding the electrically conductive element.

2. A cable coupler, characterized by 3. The cable coupler of claim 2, wherein: the housing comprises a first material having a first dielectric constant and a second material disposed proximate the mounting ends of the wires; and the second material has a second dielectric constant less than the first dielectric constant.

4. The cable coupler of claim 1 or 3, wherein: the second material is air.

5. The cable coupler of claim 1 or 3, wherein: the second material extends a length along the mounting ends of the wires of the cable, the length being in a range of 0.5 mm to 2 mm. comprise an electrically conductive layer bounding the housing. for the pair of electrically conductive elements: the first contact portions are separated from one another by a first distance; 6. The cable coupler of claim 1 or 2, wherein, the second contact portions are separated from one another by a second distance; and the second distance is greater than the first distance.

7. The cable coupler of claim 1, wherein, for the pair of electrically conductive elements: the intermediate portions are separated from one another by a third distance; and the third distance is less than the first distance. for the pair of electrically conductive elements:

8. The cable coupler of claim 7, wherein, each electrically conductive element comprises a transition portion between the intermediate portion and the second contact portion; and the transition portions are staggered from one another.

10. The cable coupler of claim 8, wherein:

9. The cable coupler of claim 8, wherein, the second material has a width substantially equal to the third distance.

11. The cable coupler of claim 1, wherein: each electrically conductive element of the pair of electrically conductive elements comprises a wide side and an edge joining the wide side; and the pair of electrically conductive elements are disposed in an edge-to-edge configuration. for the pair of electrically conductive elements: the first contact portions comprise first edges facing one another; the second contact portions comprise second edges facing one another; and the first edges are separated from one another by a first distance; and 12. The cable coupler of claim 11, wherein, the second edges are separated from one another by a second distance. ​ the second contact portion includes second edges facing each other; the intermediate portion includes third edges facing each other; the first edges are offset from the respective third edges by a first width; the second edges are offset from the respective third edges by a second width; and the second width is greater than the first width.

13. The cable coupler of claim 12, wherein: the mounting ends of the pair of wires of the cable are soldered to first edges of first contact portions of respective ones of the pair of conductive elements.

14. The cable coupler of claim 13, wherein: the cable is a first cable; and the cable coupler includes a second cable, the second cable including a pair of wires, each wire of the pair of wires including a mounting end disposed between and attached to a second edge of a second contact portion of a respective one of the pair of conductive elements.

15. The cable coupler of claim 14, wherein: the second material of the housing is also disposed between the mounting ends of the pair of wires of the second cable.

16. A cable coupler, comprising: comprises: at least one conductive element, each of the at least one conductive element including a first contact portion, a second contact portion opposite the first contact portion, and an intermediate portion between the first contact portion and the second contact portion; a housing at least partially surrounding the at least one conductive element; and a conductive layer conformally applied over the housing.

17. The cable coupler of claim 16, wherein: the at least one conductive element is a pair of conductive elements; and the cable coupler further comprises: a first cable including a pair of first wires, each first wire of the pair of first wires including a first mounting end disposed between the pair of conductive elements, the first mounting ends of the pair of first wires attached to respective ones of the first contact portions of the pair of conductive elements; and a second cable including a pair of second wires, each second wire of the pair of second wires including a second mounting end disposed between the pair of conductive elements, the second mounting ends of the pair of second wires attached to respective ones of the second contact portions of the pair of conductive elements.

18. The cable coupler of claim 17, wherein: the conductive layer is electrically connected to shield layers of the first cable and the second cable.

19. The cable coupler of claim 17, wherein: the housing includes a first cavity disposed between the first mounting ends of the first cable and a second cavity disposed between the second mounting ends of the second cable; and the first cavity and the second cavity have a smaller dielectric constant than a remainder of the housing.

20. The cable coupler of claim 19, wherein: the first cavity and the second cavity have the same dielectric constant. ​ 21. The cable coupler of claim 20, wherein: the first cavity and the second cavity are filled with air.

22. The cable coupler of claim 19, wherein: each of the first cavity and the second cavity is a cuboid.

23. The cable coupler of claim 19, wherein: the first cavity and the second cavity have different dielectric constants.

24. The cable coupler of claim 19, wherein: the first cavity has a first width and a first thickness; the second cavity has a second width and a second thickness; the second width is greater than the first width; and the second thickness is greater than the first thickness.

25. The cable coupler of claim 24, wherein: the first cavity has a first length in a longitudinal direction; and the second cavity has a second length equal to the first length.

26. The cable coupler of claim 17, wherein: the housing includes a first portion that encloses the first contact portions of the pair of conductive elements and the first mounting ends of the first cables and a second portion that encloses the second contact portions of the pair of conductive elements and the second mounting ends of the second cables; and the second portion of the housing is wider and thicker than the first portion of the housing.

27. The cable coupler of claim 17, wherein: the housing encloses the first mounting ends of the first cables and the second mounting ends of the second cables; and the conductive layer includes a first portion that is conformal to a perimeter of the first cables and a second portion that is conformal to a perimeter of the second cables. including:

28. A cable assembly, characterized by a plurality of cable couplers, each of the plurality of cable couplers including: at least one conductive element, each of the at least one conductive element including a first contact portion, a second contact portion opposite the first contact portion, and a middle portion between the first contact portion and the second contact portion; and a housing at least partially enclosing the at least one conductive element; an electrical connector including a plurality of conductive elements, each of the plurality of conductive elements including a mating end and a mounting end opposite the mating end; and a plurality of cables, each of the plurality of cables including at least one wire, each of the at least one wire including a first mounting end and a second mounting end opposite the first mounting end, wherein, for each of the plurality of cables: the first mounting end of the at least one wire is attached to a respective first contact portion of at least one conductive element of a respective cable coupler of the plurality of cable couplers; and the second mounting end of the at least one wire is attached to a respective mounting end of a respective conductive element of the plurality of conductive elements of the electrical connector.

29. The cable assembly of claim 28, wherein: the plurality of cable couplers are aligned in a plurality of rows; and the plurality of cables are aligned in a plurality of rows. The cable couplers have a center-to-center distance of no more than 2.4 mm for each row.

30. The cable assembly of claim 29, wherein: The cable couplers in adjacent rows are aligned and have a center-to-center distance of no more than 2.0 mm.

31. The cable assembly of claim 28, wherein: The plurality of cables is a plurality of first cables, each of the plurality of first cables including at least one wire having a first diameter; and The cable assembly includes a plurality of second cables, each of the plurality of second cables including at least one wire having a second diameter that is greater than the first diameter, each of the at least one wire having the second diameter including a first mounting end that is attached to a respective second contact portion of at least one conductive element of a respective cable coupler of the plurality of cable couplers.

32. The cable assembly of claim 31, wherein: The electrical connector is a first electrical connector; The cable assembly includes a second electrical connector; and For each of the plurality of second cables, each of the at least one wire having the second diameter includes a second mounting end that is terminated at the second electrical connector.

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