Cable assembly

Abstract

A cable assembly includes a circuit board including a plurality of electrically conductive pads disposed on a first major surface of the circuit board. The cable assembly further includes a cable set including a plurality of first insulated conductors and one or more first uninsulated conductors. Each of the first insulated conductors includes an electrical first conductor surrounded by an electrically first insulating material. The first insulating material is stripped between an insulation-end location on the first insulated conductor and a free end of the first insulated conductor to form a stripped section next to an unstripped section. The stripped section includes a terminated stripped end-section including the free end and terminated at a corresponding one of the conductive pads. The terminated stripped end-section leaves a remaining unterminated stripped middle-section of the stripped section extending from the insulation-end location to the terminated stripped end-section.

Description

[0001] CABLE ASSEMBLY

[0002] Technical Field

[0003] The present disclosure relates to a cable assembly.

[0004] Background

[0005] As communication data rates increase in Data Center equipment, there exists a need to maximize signal throughput of high-speed cable assemblies used to connect networking devices, such as servers and switches. These cable assemblies are typically designed to meet certain Ethernet performance specifications for insertion loss, return loss, and mode conversion. It may be difficult to match the impedance of the cable assemblies, especially at cable terminations.

[0006] Summary

[0007] In a first aspect, the present disclosure provides a cable assembly. The cable assembly includes a circuit board including a plurality of electrically conductive pads disposed on a first major surface of the circuit board. The cable assembly further includes a cable set including a plurality of first insulated conductors and one or more first uninsulated conductors extending along a length, and arranged along an orthogonal width, of the cable set. At least the first insulated conductors are surrounded by an electrically conductive shield. Each of the first insulated conductors includes an electrical first conductor having a cross-sectional area Al and surrounded by an electrically first insulating material. The first insulating material is stripped between an insulation-end location on the first insulated conductor and a free end of the first insulated conductor to form a stripped section next to an unstripped section. The stripped section includes a terminated stripped end-section including the free end and terminated at a corresponding one of the conductive pads. The terminated stripped end-section leaves a remaining unterminated stripped middle-section of the stripped section extending from the insulationend location to the terminated stripped end-section. The unterminated stripped middle-section is bent toward the first major surface substantially at the insulation-end location. For each of the first insulated conductors, in a first planar cross-section of the first insulated conductor that is substantially perpendicular to the circuit board and substantially bisects at least the unterminated stripped middlesection of the first insulated conductor, the unterminated stripped middle-section and the first major surface of the circuit board define a coupling region therebetween that extends laterally between the insulation-end location and the terminated stripped end-section. The coupling region has a cross- sectional area A2, wherein A2 < 10A1.

[0008] In a second aspect, the present disclosure provides a cable assembly. The cable assembly includes a circuit board including a plurality of electrically conductive pads disposed on a first major surface of the circuit board. The cable assembly further includes a cable set including a plurality of first insulated conductors and one or more first uninsulated conductors extending along a length, and arranged along an orthogonal width, of the cable set. At least the first insulated conductors of the cable set are surrounded by an electrically conductive shield. Each of the first insulated conductors includes an electrical first conductor surrounded by an electrically first insulating material. The first insulating material is stripped between an insulation-end location on the first insulated conductor and a free end of the first insulated conductor to form a stripped section next to an unstripped section. The stripped section includes a terminated stripped end-section including the free end and terminated at a corresponding one of the conductive pads. The terminated stripped end-section leaves a remaining unterminated stripped middle-section of the stripped section extending from the insulation-end location to the terminated stripped end-section. The cable assembly further includes an electrically grounded coupling element disposed between the unterminated stripped middle-sections of the first insulated conductors and the circuit board. The grounded coupling element is positioned so that in a plan view of the cable assembly in a direction orthogonal to the circuit board, the grounded coupling element covers at least 30% of the unterminated stripped middle-section of each of the first insulated conductors. For a planar reference plane that is substantially parallel to the first major surface of the circuit board and passes through the circuit board and is on a same side of the conductive pads and the grounded coupling element, a farthest location on the conductive pads from the reference plane that is disposed within the width of the cable set is a first distance away from the reference plane. For the planar reference plane, a farthest location on the grounded coupling element from the reference plane that is disposed within the width of the cable set is a second distance away from the reference plane. The second distance is greater than the first distance by at least 1 micron.

[0009] In a third aspect, the present disclosure provides a cable assembly. The cable assembly includes a circuit board including a plurality of electrically conductive pads disposed on a first major surface of the circuit board. The cable assembly further includes a cable set including a plurality of first insulated conductors and one or more first uninsulated conductors extending along a length, and arranged along an orthogonal width, of the cable set. At least the first insulated conductors of the cable set are surrounded by an electrically conductive shield. Each of the first insulated conductors includes an electrical first conductor surrounded by an electrically first insulating material. The first insulating material is stripped between an insulation-end location on the first insulated conductor and a free end of the first insulated conductor to form a stripped section next to an unstripped section. The stripped section includes a terminated stripped end-section including the free end and terminated at a corresponding one of the conductive pads. The terminated stripped end-section leaves a remaining unterminated stripped middle-section of the stripped section extending from the insulation-end location to the terminated stripped end-section. The cable assembly further includes an electrically grounded unitary coupling element having a unitary construction and disposed on the first major surface of the circuit board. The grounded unitary coupling element includes a first portion substantially parallel to the circuit board and a second portion extending from an end of the first portion in a direction substantially orthogonal to the circuit board. The second portion defines a plurality of first through openings substantially aligned with, and receiving the first conductors of, the first insulated conductors, in a one to one correspondence. In a plan view of the cable assembly in a direction orthogonal to the circuit board, the first portion covers at least 30% of the unterminated stripped middle-section of each of the first insulated conductors.

[0010] In a fourth aspect, the present disclosure provides a cable assembly. The cable assembly includes a circuit board including a plurality of electrically conductive pads disposed on a first major surface of the circuit board. The cable assembly further includes a cable including one or more first differential pairs and one or more first uninsulated conductors extending along a length of the cable and arranged generally in a plane along a width of the cable. Each of the differential pairs includes a plurality of first insulated conductors surrounded by an electrically conductive shield. Each of the first insulated conductors includes an electrical first conductor surrounded by an electrically first insulating material. The first insulating material is stripped between an insulation-end location on the first insulated conductor and a free end of the first insulated conductor to form a stripped section next to an unstripped section. The stripped section includes a terminated stripped end-section including the free end and terminated at a corresponding one of the conductive pads. The terminated stripped end-section leaves a remaining unterminated stripped middle-section of the stripped section extending from the insulation-end location to the terminated stripped end-section. The cable assembly further includes an electrically grounded coupling element disposed between the unterminated stripped middle-sections of the first insulated conductors of the one or more first differential pairs and the circuit board. The grounded coupling element is positioned so that in a plan view of the cable assembly in a direction orthogonal to the circuit board, the grounded coupling element covers at least 30% of the unterminated stripped middle-section of each of the first insulated conductors of the one or more first differential pairs. Across a first length of each of the first insulated conductors that begins at a beginning location on the first insulated conductor that is a part of the unstripped section proximate the insulation-end location and ends at an ending location that is a part of the terminated stripped end-section, a differential impedance of each of the differential pairs has an average Ravg and a standard of deviation Rstd, wherein Rstd / Ravg < 0.03.

[0011] In a fifth aspect, the present disclosure provides a cable assembly. The cable assembly includes a circuit board including a plurality of electrically conductive pads disposed on a first major surface of the circuit board. The cable assembly further includes a cable including one or more first differential pairs and one or more first uninsulated conductors extending along a length of the cable and arranged generally in a plane along a width of the cable. Each of the differential pairs includes a plurality of first insulated conductors surrounded by an electrically conductive shield. Each of the first insulated conductors includes an electrical first conductor surrounded by an electrically first insulating material. The first insulating material is stripped between an insulation-end location on the first insulated conductor and a free end of the first insulated conductor to form a stripped section next to an unstripped section. The stripped section includes a terminated stripped end-section including the free end and terminated at a corresponding one of the conductive pads. The terminated stripped end-section leaves a remaining unterminated stripped middle-section of the stripped section extending from the insulationend location to the terminated stripped end-section. The cable assembly further includes an electrically grounded coupling element disposed between the unterminated stripped middle-sections of the first insulated conductors of the one or more first differential pairs and the circuit board. The grounded coupling element is positioned so that in a plan view of the cable assembly in a direction orthogonal to the circuit board, the grounded coupling element covers at least 30% of the unterminated stripped middle-section of each of the first insulated conductors of the one or more first differential pairs. For each of the one or more first differential pairs and for at least a frequency in a frequency range that extends from about 10 GHz to about 30 GHz, a differential return loss of the differential pair is less than about -25 dB.

[0012] Brief Description of the Drawings

[0013] Exemplary embodiments disclosed herein are more completely understood in consideration of the following detailed description in connection with the following figures. The figures are not necessarily drawn to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labelled with the same number.

[0014] FIG. 1 A is a schematic perspective top view of a cable assembly, according to an embodiment of the present disclosure;

[0015] FIG. IB is a schematic top view of the cable assembly of FIG. 1 A, according to an embodiment of the present disclosure;

[0016] FIG. 1C is a schematic side view of the cable assembly of FIG. 1A, with some components not shown, according to an embodiment of the present disclosure;

[0017] FIG. ID is a schematic sectional side view of the cable assembly taken along a line A-A’ shown in FIG. IB, with some components not shown, according to an embodiment of the present disclosure;

[0018] FIG. IE is a schematic partial sectional side view of the cable assembly taken along a line B- B’ shown in FIG. IB, according to an embodiment of the present disclosure;

[0019] FIG. IF is a schematic front view of the cable assembly of FIG. 1A, with some components not shown, according to an embodiment of the present disclosure;

[0020] FIG. 2 is a schematic perspective view of a cable assembly, according to another embodiment of the present disclosure;

[0021] FIG. 3 is a graph depicting differential return loss versus frequency for the cable assembly of FIG. 1A and a corresponding comparative cable assembly, according to an embodiment of the present disclosure;

[0022] FIG. 4 is a graph depicting impedance versus time for the cable assembly of FIG. 1A and a corresponding comparative cable assembly, according to an embodiment of the present disclosure;

[0023] FIG. 5A is a schematic perspective top view of a cable assembly, according to another embodiment of the present disclosure;

[0024] FIG. 5B is a schematic top view of the cable assembly of FIG. 5 A, according to an embodiment of the present disclosure; FIG. 5C is a schematic side view of the cable assembly of FIG. 5 A, with some components not shown, according to an embodiment of the present disclosure;

[0025] FIG. 5D is a schematic sectional side view of the cable assembly taken along a line C-C’ shown in FIG. 5B, with some components not shown, according to an embodiment of the present disclosure;

[0026] FIG. 5E is another schematic side view of the cable assembly of FIG. 5A, with some components not shown, according to an embodiment of the present disclosure;

[0027] FIG. 5F is another schematic perspective top view of the cable assembly of FIG. 5 A, with some components not shown, according to an embodiment of the present disclosure;

[0028] FIG. 6 is a graph depicting differential return loss versus frequency for the cable assembly of FIG. 5A and a corresponding comparative cable assembly, according to an embodiment of the present disclosure;

[0029] FIG. 7 is a graph depicting impedance versus time for the cable assembly of FIG. 5A and a corresponding comparative cable assembly, according to an embodiment of the present disclosure;

[0030] FIG. 8A is a schematic perspective top view of a cable assembly, according to another embodiment of the present disclosure;

[0031] FIG. 8B is a schematic top view of the cable assembly of FIG. 8 A, according to an embodiment of the present disclosure;

[0032] FIG. 8C is a schematic side view of the cable assembly of FIG. 8 A, with some components not shown, according to an embodiment of the present disclosure;

[0033] FIG. 8D is a schematic sectional side view of the cable assembly taken along a line D-D’ shown in FIG. 8B, with some components not shown, according to an embodiment of the present disclosure;

[0034] FIG. 8E is another schematic side view of the cable assembly of FIG. 8A, with some components not shown, according to an embodiment of the present disclosure;

[0035] FIG. 8F is another schematic perspective top view of the cable assembly of FIG. 8 A, with some components not shown, according to an embodiment of the present disclosure;

[0036] FIG. 9 is a schematic side view of a cable assembly, according to another embodiment of the present disclosure;

[0037] FIG. 10 is a graph depicting differential return loss versus frequency for the cable assembly of FIG. 8A and a corresponding comparative cable assembly, according to an embodiment of the present disclosure;

[0038] FIG. 11 is a graph depicting impedance versus time for the cable assembly of FIG. 8A and a corresponding comparative cable assembly, according to an embodiment of the present disclosure;

[0039] FIG. 12A is a schematic perspective top view of a cable assembly, according to another embodiment of the present disclosure;

[0040] FIG. 12B is a schematic top view of the cable assembly of FIG. 12 A, according to an embodiment of the present disclosure;

[0041] FIG. 12C is a schematic side view of the cable assembly of FIG. 12A, with some components not shown, according to an embodiment of the present disclosure; FIG. 12D is a schematic sectional side view of the cable assembly taken along a line E-E’ shown in FIG. 12B, with some components not shown, according to an embodiment of the present disclosure;

[0042] FIG. 13 is a graph depicting differential return loss versus frequency for the cable assembly of FIG. 12A and a corresponding comparative cable assembly, according to an embodiment of the present disclosure;

[0043] FIG. 14 is a graph depicting impedance versus time for the cable assembly of FIG. 12A and a corresponding comparative cable assembly, according to an embodiment of the present disclosure; and FIG. 15 is a graph depicting impedance versus time for the cable assemblies of FIGS. 1A, 5A, 8A, and 12A, and their corresponding comparative cable assemblies, according to an embodiment of the present disclosure.

[0044] Detailed Description

[0045] In the following description, reference is made to the accompanying figures that form a part thereof and in which various embodiments are shown by way of illustration. It is to be understood that other embodiments are contemplated and are without departing from the scope or spirit of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense.

[0046] In the following disclosure, the following definitions are adopted.

[0047] As used herein, all numbers should be considered modified by the term “about”. As used herein, “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably.

[0048] As used herein as a modifier to a property or attribute, the term “generally”, unless otherwise specifically defined, means that the property or attribute would be readily recognizable by a person of ordinary skill but without requiring absolute precision or a perfect match (e.g., within + / - 20 % for quantifiable properties).

[0049] The term “substantially”, unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 10% for quantifiable properties) but again without requiring absolute precision or a perfect match.

[0050] The term “about”, unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 5% for quantifiable properties) but again without requiring absolute precision or a perfect match.

[0051] As used herein, the terms “first” and “second” are used as identifiers. Therefore, such terms should not be construed as limiting of this disclosure. The terms “first” and “second” when used in conjunction with a feature or an element can be interchanged throughout the embodiments of this disclosure.

[0052] As used herein, “at least one of A and B” should be understood to mean “only A, only B, or both A and B”. As used herein, the term “between about”, unless otherwise specifically defined, generally refers to an inclusive or a closed range. For example, if a parameter X is between about A and B, then A < X < B.

[0053] As used herein, the term “return loss”, refers to a measure in relative terms of the power of a signal reflected by a discontinuity in a transmission line.

[0054] As used herein, the term “mode conversion”, refers to a conversion of a differential signal into a common-mode signal.

[0055] As used herein, the term “differential impedance”, refers to a difference in signal level between a pair of transmission lines at a receiver

[0056] The amount of data transferred between electronic devices has grown tremendously in the last several years. Large amounts of audio, streaming video, text, and other types of data content are now regularly transferred among desktop and portable computers, media devices, handheld media devices, displays, storage devices, and other types of electronic devices. Since it is often desirable to transfer this data rapidly, the data rates of these transfers have substantially increased. Due to such increased data rates, there exists a need to maximize signal throughput of high-speed cable assemblies used to connect servers and switches. These cable assemblies are typically designed to meet certain Ethernet performance specifications for insertion loss, return loss, and mode conversion. While it is difficult to minimize insertion loss of the cable assemblies (which is principally due to the inherent attenuation presented by cables and connectors) beyond a certain level, reducing the return loss and the mode conversion may reduce the amount of signal that is converted out of differential transmission mode or reflected back toward a source.

[0057] Cable terminations to printed circuit boards (PCBs) inside connector housings have traditionally been one area that is prone to large reflections and are a high return loss contributor. This behavior is usually caused by drastic geometry / material change that occurs when conductor wires are stripped off an end of a cable and the cable is soldered to receiving pads on a surface of the PCB. While the cable assemblies used for Data Center communication typically have a desirable target average impedance (e.g., 100 ohms), the stripped bare ends of the wires generally exhibit a much higher average impedance. Further, it may be difficult to keep the soldered wire termination to the PCB from exhibiting the average impedance much below the desirable target average impedance.

[0058] The present disclosure provides a cable assembly. The cable assembly includes a circuit board including a plurality of electrically conductive pads disposed on a first major surface of the circuit board. The cable assembly further includes a cable set including a plurality of first insulated conductors and one or more first uninsulated conductors extending along a length, and arranged along an orthogonal width, of the cable set. At least the first insulated conductors are surrounded by an electrically conductive shield. Each of the first insulated conductors includes an electrical first conductor having a cross-sectional area Al and surrounded by an electrically first insulating material. The first insulating material is stripped between an insulation-end location on the first insulated conductor and a free end of the first insulated conductor to form a stripped section next to an unstripped section. The stripped section includes a terminated stripped end-section including the free end and terminated at a corresponding one of the conductive pads. The terminated stripped end-section leaves a remaining unterminated stripped middle-section of the stripped section extending from the insulation-end location to the terminated stripped end-section. The unterminated stripped middle-section is bent toward the first major surface substantially at the insulation-end location. For each of the first insulated conductors, in a first planar cross-section of the first insulated conductor that is substantially perpendicular to the circuit board and substantially bisects at least the unterminated stripped middle-section of the first insulated conductor, the unterminated stripped middle-section and the first major surface of the circuit board define a coupling region therebetween that extends laterally between the insulation-end location and the terminated stripped end-section. The coupling region has a cross-sectional area A2, wherein A2 < 10A1.

[0059] In some embodiments, the cable assembly includes an electrically grounded coupling element disposed on the first major surface of the circuit board. The grounded coupling element is positioned so that in a plan view of the cable assembly in a direction orthogonal to the circuit board, the grounded coupling element covers the insulation-end location and at least 30% of the unterminated stripped middle-section of each of the first insulated conductors.

[0060] For each of the first insulated conductors, due to bending of the unterminated stripped middlesection toward the first major surface substantially at the insulation-end location and the extension of the coupling region laterally between the insulation-end location and the terminated stripped endsection, each of the first insulated conductors is relatively closer to the grounded coupling element as compared to conventional cable assemblies. This bending of the unterminated stripped middle-section toward the first major surface may reduce a distance between the unterminated stripped middle-section and the grounded coupling element. Such bending of the unterminated stripped middle-section may reduce an average impedance of the stripped section. This may further reduce any impedance discontinuity between the stripped section and the unstripped section of each of the first insulated conductors of the cable assembly. This may further lead to reduced signal reflections and return loss in the cable assembly of the present disclosure. Therefore, the cable of the present disclosure may provide improved performance due to the reduced mode conversion and return loss.

[0061] In another embodiment, the present disclosure provides a cable assembly. The cable assembly includes a circuit board including a plurality of electrically conductive pads disposed on a first major surface of the circuit board. The cable assembly further includes a cable set including a plurality of first insulated conductors and one or more first uninsulated conductors extending along a length, and arranged along an orthogonal width, of the cable set. At least the first insulated conductors of the cable set are surrounded by an electrically conductive shield. Each of the first insulated conductors includes an electrical first conductor surrounded by an electrically first insulating material. The first insulating material is stripped between an insulation-end location on the first insulated conductor and a free end of the first insulated conductor to form a stripped section next to an unstripped section. The stripped section includes a terminated stripped end-section including the free end and terminated at a corresponding one of the conductive pads. The terminated stripped end-section leaves a remaining unterminated stripped middle-section of the stripped section extending from the insulation-end location to the terminated stripped end-section. The cable assembly further includes an electrically grounded coupling element disposed between the unterminated stripped middle-sections of the first insulated conductors and the circuit board. The grounded coupling element is positioned so that in a plan view of the cable assembly in a direction orthogonal to the circuit board, the grounded coupling element covers at least 30% of the unterminated stripped middle-section of each of the first insulated conductors. For a planar reference plane that is substantially parallel to the first major surface of the circuit board and passes through the circuit board and is on a same side of the conductive pads and the grounded coupling element, a farthest location on the conductive pads from the reference plane that is disposed within the width of the cable set is a first distance away from the reference plane. For the planar reference plane, a farthest location on the grounded coupling element from the reference plane that is disposed within the width of the cable set is a second distance away from the reference plane. The second distance is greater than the first distance by at least 1 micron.

[0062] The inclusion of the grounded coupling element between the unterminated stripped middlesections of the first insulated conductors and the circuit board provides a ground reference in close proximity to the first insulated conductors. This may reduce any impedance discontinuity between the stripped section and the unstripped section of each of the first insulated conductors of the cable assembly of the present disclosure. Therefore, the reduced impedance discontinuity may improve the overall performance of the cable assembly of the present disclosure by reducing the return losses.

[0063] In another embodiment, the present disclosure provides a cable assembly. The cable assembly includes a circuit board including a plurality of electrically conductive pads disposed on a first major surface of the circuit board. The cable assembly further includes a cable set including a plurality of first insulated conductors and one or more first uninsulated conductors extending along a length, and arranged along an orthogonal width, of the cable set. At least the first insulated conductors of the cable set are surrounded by an electrically conductive shield. Each of the first insulated conductors includes an electrical first conductor surrounded by an electrically first insulating material. The first insulating material is stripped between an insulation-end location on the first insulated conductor and a free end of the first insulated conductor to form a stripped section next to an unstripped section. The stripped section includes a terminated stripped end-section including the free end and terminated at a corresponding one of the conductive pads. The terminated stripped end-section leaves a remaining unterminated stripped middle-section of the stripped section extending from the insulation-end location to the terminated stripped end-section. The cable assembly further includes an electrically grounded unitary coupling element having a unitary construction and disposed on the first major surface of the circuit board. The grounded unitary coupling element includes a first portion substantially parallel to the circuit board and a second portion extending from an end of the first portion in a direction substantially orthogonal to the circuit board. The second portion defines a plurality of first through openings substantially aligned with, and receiving the first conductors of, the first insulated conductors, in a one to one correspondence. In a plan view of the cable assembly in a direction orthogonal to the circuit board, the first portion covers at least 30% of the unterminated stripped middle-section of each of the first insulated conductors.

[0064] The inclusion of the grounded unitary coupling element on the first major surface of the circuit board provides a ground reference in close proximity to the first insulated conductors. This may reduce any impedance discontinuity between the stripped section and the unstripped section of each of the first insulated conductors, and thereby improve the overall performance of the cable assembly of the present disclosure by reducing the return losses.

[0065] In another embodiment, the present disclosure provides a cable assembly. The cable assembly includes a circuit board including a plurality of electrically conductive pads disposed on a first major surface of the circuit board. The cable assembly further includes a cable including one or more first differential pairs and one or more first uninsulated conductors extending along a length of the cable and arranged generally in a plane along a width of the cable. Each of the differential pairs includes a plurality of first insulated conductors surrounded by an electrically conductive shield. Each of the first insulated conductors includes an electrical first conductor surrounded by an electrically first insulating material. The first insulating material is stripped between an insulation-end location on the first insulated conductor and a free end of the first insulated conductor to form a stripped section next to an unstripped section. The stripped section includes a terminated stripped end-section including the free end and terminated at a corresponding one of the conductive pads. The terminated stripped end-section leaves a remaining unterminated stripped middle-section of the stripped section extending from the insulation-end location to the terminated stripped end-section. The cable assembly further includes an electrically grounded coupling element disposed between the unterminated stripped middle-sections of the first insulated conductors of the one or more first differential pairs and the circuit board. The grounded coupling element is positioned so that in a plan view of the cable assembly in a direction orthogonal to the circuit board, the grounded coupling element covers at least 30% of the unterminated stripped middle-section of each of the first insulated conductors of the one or more first differential pairs. For each of the one or more first differential pairs and for at least a frequency in a frequency range that extends from about 10 GHz to about 30 GHz, a differential return loss of the differential pair is less than about -25 dB.

[0066] As discussed above, a reduced return loss in the cable assembly may be desirable and may lead to an improved performance of the cable assembly of the present disclosure.

[0067] Referring now to figures, FIG. 1 A is a schematic perspective top view of a cable assembly 300, according to an embodiment of the present disclosure. FIG. IB is a schematic top view of the cable assembly 300. FIG. 1C is a schematic side view of the cable assembly 300, with some components not shown. FIG. ID is a schematic sectional side view of the cable assembly 300 taken along a line A-A’ shown in FIG. IB, with some components not shown. FIG. IE is a schematic partial sectional side view of the cable assembly 300 taken along a line B-B ’ shown in FIG. IB, with some components not shown. FIG. IF is a schematic front view of the cable assembly 300, with some components not shown. Referring to FIGS. 1A to IF, the cable assembly 300 defines mutually orthogonal x, y, and z- axes. The x and y-axes are in-plane axes of the cable assembly 300, while the z-axis is a transverse axis disposed along a thickness of the cable assembly 300. In other words, x and y-axes are along a plane of the cable assembly 300 defining a x-y plane, and the z-axis is perpendicular to the x-y plane of the cable assembly 300.

[0068] The cable assembly 300 includes a circuit board 10 including a plurality of electrically conductive pads 11. The plurality of conductive pads 11 serve as the designated surface area for electrical contact between a component and the circuit board 10. The plurality of conductive pads 11 are disposed on a first major surface 12 of the circuit board 10. The cable assembly 300 further includes a cable set 20. In some embodiments, the cable set 20 can be interchangeably referred to herein as “the cable 20”.

[0069] The cable 20 includes one or more first differential pairs 22. Each of the differential pairs 22 includes a plurality of first insulated conductors 30 surrounded by an electrically conductive shield 50 (shown in FIG. 1 A). In other words, the cable set 20 includes the plurality of first insulated conductors 30. The cable set 20 further includes one or more first uninsulated conductors 40. The plurality of first insulated conductors 30 and the one or more first uninsulated conductors 40 extend along a length (i.e., substantially along the x-axis) of the cable 20 and are arranged along an orthogonal width (i.e., substantially along the y-axis) of the cable 20. In other words, the plurality of first insulated conductors

[0070] 30 and the one or more first uninsulated conductors 40 extend along the length of the cable 20 and are arranged generally in a plane along the width of the cable 20. At least the first insulated conductors 30 are surrounded by the electrically conductive shield 50.

[0071] In some embodiments, the plurality of first insulated conductors 30 includes a total of two first insulated conductors 30. In some other embodiments, the plurality of first insulated conductors 30 may include more than two first insulated conductors 30. In some embodiments, the one or more first uninsulated conductors 40 include a total of two first uninsulated conductors 40. In some other embodiments, the one or more first uninsulated conductors 40 may include more than two first uninsulated conductors 40.

[0072] In some embodiments, the cable set 20 further includes an external jacket 21 (shown in FIG. IB) disposed around the first insulated conductors 30 and the one or more first uninsulated conductors 40 such that the electrically conductive shield 50 (shown in FIG. 1 A) is disposed between the external jacket 21 and the first insulated conductors 30 and the one or more first uninsulated conductors 40. In FIGS. 1C, ID, and IF, the external jacket 21 and the electrically conductive shield 50 are not shown for illustrative purposes. In FIG. 1A, the external jacket 21 is not shown for illustrative purposes.

[0073] Each of the first insulated conductors 30 includes an electrical first conductor 31 having a cross- sectional area Al (shown in FIG. IF) and surrounded by an electrically first insulating material 32. In some embodiments, the first conductor 31 of at least one of the first insulated conductors 30 has a diameter of no greater than 20 American wire gauge (AWG). In some embodiments, the first conductor

[0074] 31 of the at least one of the first insulated conductors 30 has a diameter of no greater than 21 AWG, no greater than 22 AWG, no greater than 24 AWG, no greater than 26 AWG, no greater than 28 AWG, no greater than 30 AWG, no greater than 32 AWG, or no greater than 34 AWG. In some embodiments, the uninsulated conductor 40 of at least one of the one or more first uninsulated conductors 40 has a diameter of no greater than 20 AWG. In some embodiments, the uninsulated conductor 40 of the at least one of the one or more first uninsulated conductors 40 has a diameter of no greater than 21 AWG, no greater than 22 AWG, no greater than 24 AWG, no greater than 26 AWG, no greater than 28 AWG, no greater than 30 AWG, no greater than 32 AWG, or no greater than 34 AWG. In some embodiments, the diameter of the uninsulated conductor 40 of the at least one of the one or more first uninsulated conductors 40 is less than the diameter of the first conductor 31 of the at least one of the first insulated conductors 30.

[0075] The first insulating material 32 is stripped between an insulation-end location 33 on the first insulated conductor 30 and a free end 34 of the first insulated conductor 30 to form a stripped section 35 next to an unstripped section 36. The stripped section 35 includes a terminated stripped end-section 37 including the free end 34 and terminated at a corresponding one of the conductive pads 11. The terminated stripped end-section 37 leaves a remaining unterminated stripped middle-section 38 of the stripped section 35 extending from the insulation-end location 33 to the terminated stripped end-section 37.

[0076] The cable assembly 300 further includes an electrically grounded coupling element 53 disposed on the first major surface 12 of the circuit board 10. The electrically grounded coupling element 53 is disposed between the unterminated stripped middle-sections 38 of the first insulated conductors 30 of the one or more first differential pairs 22 and the circuit board 10. The grounded coupling element 53 is positioned so that in a plan view (shown in FIG. IB in the x-y plane) of the cable assembly 300 in a direction (i.e., substantially along the z-axis) orthogonal to the circuit board 10, the grounded coupling element 53 covers the insulation-end location 33 and at least 30% of the unterminated stripped middlesection 38 of each of the first insulated conductors 30 of the one or more first differential pairs 22. In some embodiments, the grounded coupling element 53 is positioned so that in the plan view of the cable assembly 300 in the direction orthogonal to the circuit board 10, the grounded coupling element 53 covers at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, or at least 70% of the unterminated stripped middle-section 38 of each of the first insulated conductors 30 of the one or more first differential pairs 22.

[0077] In some embodiments, the grounded coupling element 53 is at least partially embedded in the circuit board 10. In some embodiments, uppermost surfaces of the electrically conductive pads 11 and the electrically grounded coupling element 53 are substantially co-planar. In some embodiments, the electrically conductive pads 11 and the electrically grounded coupling element 53 have substantially a same average thickness (i.e., substantially along the z-axis). In some embodiments, the grounded coupling element 53 is substantially flat.

[0078] In the illustrated embodiment of FIGS. 1 A to IF, the cable assembly 300 further includes an electrically insulative cover layer 54 disposed on the grounded coupling element 53. The electrically insulative cover layer 54 is positioned to prevent the unterminated stripped middle-sections 38 of the first insulated conductors 30 from making at least one of electrical and physical contact with the grounded coupling element 53. In some embodiments, the electrically insulative cover layer 54 includes a solder mask.

[0079] Further, in the illustrated embodiment of FIGS. 1A to IF, the unterminated stripped middlesection 38 is bent toward the first major surface 12 substantially at the insulation-end location 33. For each of the first insulated conductors 30, in a first planar cross-section Pl (i.e., in the x-z plane, as shown in FIG. IE) of the first insulated conductor 30 that is substantially perpendicular to the circuit board 10 and substantially bisects at least the unterminated stripped middle-section 38 of the first insulated conductor 30, the unterminated stripped middle-section 38 and the first major surface 12 of the circuit board 10 define a coupling region 14 (shown in FIG. IE) therebetween. The coupling region 14 extends laterally between the insulation-end location 33 and the terminated stripped end-section 37. The coupling region 14 has a cross-sectional area A2 (indicated by the dotted region in FIG. IE). The cross-sectional area A2 of the coupling region 14 is less than or equal to 10 times of the cross-sectional area Al (shown in FIG. IF) of the electrical first conductor 31, i.e., A2 < 10A1. In some embodiments, A2 < 9A1, A2 < 8A1, A2 < 7A1, A2 < 6A1, A2 < 5A1, or A2 < 4A1.

[0080] Further, for each of the first insulated conductors 30, the bending of the unterminated stripped middle-section 38 toward the first major surface 12 substantially at the insulation-end location 33 forms a first bent portion 38a of the unterminated stripped middle-section 38.

[0081] In the first planar cross-section Pl (shown in FIG. IE) of the first insulated conductor 30, the first bent portion 38a makes an angle bl with a second planar cross-section P2 (i.e., the y-z plane, as shown in FIG. IE) of the first insulated conductor 30. The second planar cross-section P2 includes the insulation-end location 33 and is substantially orthogonal to the first planar cross-section Pl and the circuit board 10. In some embodiments, the angle bl is less than or equal to 80 degrees, i.e., bl < 80 degrees. In some embodiments, bl < 75 degrees, bl < 70 degrees, or bl < 65 degrees.

[0082] Further, for each of the first insulated conductors 30, the unterminated stripped middle-section 38 further includes a second bent portion 38b that extends from an end of the first bent portion 38a toward the first major surface 12. In the first planar cross-section P 1 of the first insulated conductor 30, the second bent portion 38b makes an angle b2 with the second planar cross-section P2 of the first insulated conductor 30. In some embodiments, the angle b2 is greater than or equal to 50 degrees, i.e., b2 > 50 degrees. In some embodiments, b2 > 55 degrees, b2 > 60 degrees, b2 > 65 degrees, b2 > 70 degrees, b2 > 75 degrees, b2 > 80 degrees, or b2 > 85 degrees.

[0083] In the illustrated embodiments of FIGS. 1A to IF, the grounded coupling element 53 is positioned so that in the plan view of the cable assembly 300 in the direction (i.e., substantially along the z-axis) orthogonal to the circuit board 10, the grounded coupling element 53 covers the insulationend location 33 and at least 30% of the first bent portion 38a of the unterminated stripped middle-section 38 of each of the first insulated conductors 30. In some embodiments, the grounded coupling element 53 is positioned so that in the plan view of the cable assembly 300 in the direction orthogonal to the circuit board 10, the grounded coupling element 53 covers at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, or at least 99% of the first bent portion 38a of the unterminated stripped middle-section 38 of each of the first insulated conductors 30. Moreover, the electrically insulative cover layer 54 is positioned to prevent the first bent portions 38a of the unterminated stripped middle-sections 38 of the first insulated conductors 30 from making at least one of electrical and physical contact with the grounded coupling element 53.

[0084] FIG. 2 is a schematic perspective view of a cable assembly 311, according to another embodiment of the present disclosure. The cable assembly 311 is substantially similar to the cable assembly 300 of FIG. 1A, with common components being referred to as by the same numerals. However, the cable assembly 311 further includes a continuous top encapsulant 60 substantially sealing a portion of the unstripped sections 36 (shown in FIG. 1C) of the first insulated conductors 30, and the entireties of the stripped sections 35 (shown in FIG. 1C) of the first insulated conductors 30. In some embodiments, the encapsulant 60 includes an adhesive. In some embodiments, the encapsulant 60 includes an overmold molded over the portion of the unstripped sections 36 of the first insulated conductors 30, and the entireties of the stripped sections 35 of the first insulated conductors 30.

[0085] FIG. 3 is a graph 100 depicting return loss versus frequency for the cable assembly 300 of FIG. 1A and a corresponding comparative cable assembly, according to an embodiment of the present disclosure. The cable assembly 300 and the corresponding comparative cable assembly have the same construction except that the unterminated stripped middle-section is not bent toward the first major surface in the corresponding comparative cable assembly. The frequency is expressed in Gigahertz (GHz) in the abscissa. The return loss is expressed in decibels (dB) in the ordinate.

[0086] Referring to FIGS. 1A and 3, the graph 100 includes curves 102, 104. The curve 102 depicts the return loss versus frequency for the cable assembly 300. The curve 104 depicts the return loss versus frequency for the corresponding comparative cable assembly. For each of the one or more first differential pairs 22 and for at least a frequency Fl in a frequency range that extends from about 10 GHz to about 30 GHz, a differential return loss RL1 of the differential pair 22 is less than about -25 dB. In some embodiments, for at least the frequency Fl in the frequency range that extends from about 10 GHz to about 30 GHz, the differential return loss RL1 of the differential pair 22 is less than about -26 dB, less than about -27 dB, less than about -28 dB, less than about -29 dB, or less than about -30 dB.

[0087] In some embodiments, for each of the first differential pairs 22 and for at least one frequency Fl’ of greater than about 35 GHz, a return loss RL1’ of the first differential pair 22 is less than about - 25 dB. In some embodiments, for each of the first differential pairs 22 and for the at least one frequency Fl’ of greater than about 35 GHz, the return loss RL1’ of the first differential pair 22 is less than about -30 dB, or less than about -32 dB.

[0088] As is apparent from the curve 104 of the graph 100, for each of one or more first differential pairs of the corresponding comparative cable assembly and for each frequency in the frequency range that extends from about 10 GHz to about 30 GHz, a differential return loss of the differential pair of the corresponding comparative cable assembly is greater than about -25 dB.

[0089] FIG. 4 is a graph 106 depicting impedance versus time for the cable assembly 300 of FIG. 1A and the corresponding comparative cable assembly, according to an embodiment of the present disclosure. The time is expressed in picoseconds (ps) in the abscissa. The impedance is expressed in Ohms in the ordinate.

[0090] Referring to FIGS. ID and 4, the graph 106 includes curves 108, 110. The curve 108 depicts impedance versus time for the cable assembly 300. The curve 110 depicts impedance versus time for the corresponding comparative cable assembly. Across a first length LI of each of the first insulated conductors 30 that begins at a beginning location 90 (also see FIG. ID) on the first insulated conductor 30 that is a part of the unstripped section 36 proximate the insulation-end location 33 and ends at an ending location 91 (also see FIG. ID) that is a part of the terminated stripped end-section 37, a differential impedance of each of the differential pairs 22 has an average Ravg and a standard of deviation Rstd. In some embodiments, Rstd / Ravg is less than 0.03, i.e., Rstd / Ravg < 0.03. In some embodiments, across the first length LI of each of the first insulated conductors 30, Rstd / Ravg < 0.25, or Rstd / Ravg < 0.02. As per the curve 110, across the same first length LI, for the differential pairs of the corresponding comparative cable assembly, Rstd / Ravg is equal to about 0.04, which is greater than the Rstd / Ravg of the cable assembly 300. Therefore, the cable assembly 300 may have reduced impedance discontinuity in each of the first insulated conductors 30 as compared to the corresponding comparative cable assembly.

[0091] In some embodiments, the beginning location 90 is within 10 mm of the insulation-end location 33. In some other embodiments, the beginning location 90 is within 9 mm, within 8 mm, within 7 mm, within 6 mm, within 5 mm, within 4 mm, within 3 mm, within 2 mm, within 1 mm, or within 0.75 mm of the insulation-end location 33.

[0092] In some embodiments, the ending location 91 is within 10 mm of the free end 34 of the first insulated conductor 30. In some other embodiments, the ending location 91 is within 9 mm, within 8 mm, within 7 mm, within 6 mm, within 5 mm, within 4 mm, within 3 mm, within 2 mm, within 1 mm, or within 0.75 mm of the free end 34 of the first insulated conductor 30.

[0093] In some embodiments, the first length LI is at least 0.5 mm. In some other embodiments, the first length LI is at least 0.6 mm, at least 0.7 mm, at least 0.8 mm, at least 0.9 mm, at least 1 mm, at least 1.1 mm, at least 1.25 mm, at least 1.5 mm, or at least 2 mm.

[0094] In some embodiments, the first length LI is at most 10 mm. In some other embodiments, the first length LI is at most 9 mm, at most 8 mm, at most 7 mm, at most 6 mm, at most 5 mm, or at most 4 mm.

[0095] Referring to the curve 108, in some embodiments, a characteristic differential impedance of each of the first differential pairs 22 is between about 85 ohms and about 110 ohms over a cable length of about 1 meter. In some embodiments, the characteristic differential impedance of each of the first differential pairs 22 is about 100 ohms over the cable length of about 1 meter. Such a value of the differential impedance of each of the first differential pairs 22 of the cable assembly 300 may correspond to a desirable target differential impedance of the cable assembly 300 in order to reduce the return loss and mode conversion in the cable assembly 300.

[0096] Referring again to FIGS. 1 A to IF, for each of the first insulated conductors 30, due to bending of the unterminated stripped middle-section 38 toward the first major surface 12 substantially at the insulation-end location 33 and the extension of the coupling region 14 laterally between the insulationend location 33 and the terminated stripped end-section 37, each of the first insulated conductors 30 is relatively closer to the grounded coupling element 53 as compared to conventional cable assemblies. This bending of the unterminated stripped middle-section 38 toward the first major surface 12 may reduce a distance between the unterminated stripped middle-section 38 and the grounded coupling element 53. Such bending of the unterminated stripped middle-section 38 may reduce average impedance of the stripped section 35. This may further reduce the impedance discontinuity between the stripped section 35 and the unstripped section 36 of each of the first insulated conductors 30 of the cable assembly 300. This may further lead to reduced signal reflections and return loss in the cable assembly 300. Therefore, the cable assembly 300 may provide improved performance due to the reduced mode conversion and return loss.

[0097] FIG. 5A is a schematic perspective top view of a cable assembly 310, according to another embodiment of the present disclosure. FIG. 5B is a schematic top view of the cable assembly 310. FIG. 5C is schematic a side view of the cable assembly 310, with some components not shown. FIG. 5D is a schematic sectional side view of the cable assembly 310 taken along a line C-C’ shown in FIG. 5B, with some components not shown. FIG. 5E is another schematic side view of the cable assembly 310 of FIG. 5 A, with some components not shown. FIG. 5F is another schematic perspective top view of the cable assembly 310, with some components not shown.

[0098] The cable assembly 310 is substantially similar to the cable assembly 300 shown in FIGS. 1 A to IF, with common components being referred to by the same reference numerals. The functional advantage of the cable assembly 310 is substantially the same as that of the cable assembly 300. However, in the cable assembly 310, the unterminated stripped middle-section 38 is not bent toward the first major surface 12 substantially at the insulation-end location 33. Further, the cable assembly 310 does not include an electrically insulative cover layer (i.e., the electrically insulative cover layer 54 shown in FIG. 1A) disposed on the grounded coupling element 53. In FIGS. 5C and 5D, the external jacket 21 and the electrically conductive shield 50 are not shown for illustrative purposes. In FIG. 5 A, the external jacket 21 is not shown for illustrative purposes. In FIGS. 5E and 5F, the external jacket 21, the electrical first conductors 31 of the plurality of first insulated conductors 30, and the one or more first uninsulated conductors 40 are not shown for illustrative purposes.

[0099] Referring to FIGS. 5A to 5F, the cable assembly 310 includes an electrically grounded coupling element 70a disposed between the unterminated stripped middle-sections 38 (shown in FIG. 5D) of the first insulated conductors 30 and the circuit board 10. The electrically grounded coupling element 70a is positioned so that in a plan view (shown in FIG. 5B in the x-y plane) of the cable assembly 310 in a direction (i.e., substantially along the z-axis) orthogonal to the circuit board 10, the grounded coupling element 70a covers at least 30% of the unterminated stripped middle-section 38 of each of the first insulated conductors 30. In some embodiments, the electrically grounded coupling element 70a is positioned so that in the plan view of the cable assembly 310 in the direction orthogonal to the circuit board 10, the grounded coupling element 70a covers at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, or at least 70% of the unterminated stripped middlesection 38 of each of the first insulated conductors 30. As shown in FIG. 5F, in some embodiments, the conductive pads 11 in the plurality of electrically conductive pads 11 are arranged in one or more parallel rows of the conductive pads 11.

[0100] For a planar reference plane P3 (i.e., in the x-y plane, as shown in FIG. 5E) that is substantially parallel to the first major surface 12 of the circuit board 10 and passes through the circuit board 10 and is on a same side of the conductive pads 11 and the grounded coupling element 70a, a farthest location I la (shown in FIGS. 5E and 5F) on the conductive pads 11 from the reference plane P3 that is disposed within the width of the cable set 20 is a first distance xa (shown in FIG. 5E) away from the reference plane P3. Moreover, for the planar reference plane P3, a farthest location 73a (shown in FIGS. 5E and 5F) on the grounded coupling element 70a from the reference plane P3 that is disposed within the width of the cable set 20 is a second distance ya (shown in FIG. 5E) away from the reference plane P3.

[0101] In some embodiments, the second distance ya is greater than the first distance xa by at least 1 micron. In some embodiments, the second distance ya is greater than the first distance xa by at least 2 microns, at least 3 microns, at least 4 microns, at least 5 microns, at least 10 microns, at least 15 microns, at least 20 microns, at least 50 microns, at least 75 microns, at least 100 microns, at least 150 microns, at least 200 microns, at least 250 microns, or at least 300 microns.

[0102] FIG. 6 is a graph 112 depicting return loss versus frequency for the cable assembly 310 of FIG. 5A and a corresponding comparative cable assembly, according to an embodiment of the present disclosure. The cable assembly 310 and the corresponding comparative cable assembly have the same construction except that the corresponding comparative cable assembly does not include any electrically grounded coupling element (i.e., the electrically grounded coupling element 70a shown in FIG. 5A). The frequency is expressed in Gigahertz (GHz) in the abscissa. The return loss is expressed in decibels (dB) in the ordinate.

[0103] Referring to FIGS. 5 A and 6, the graph 112 includes curves 114, 116. The curve 114 depicts the return loss versus frequency for the cable assembly 310. The curve 116 depicts the return loss versus frequency for the corresponding comparative cable assembly. For each of the one or more first differential pairs 22 and for at least a frequency F2 in a frequency range that extends from about 10 GHz to about 30 GHz, a differential return loss RL2 of the differential pair 22 is less than about -25 dB. In some embodiments, for at least the frequency F2 in the frequency range that extends from about 10 GHz to about 30 GHz, the differential return loss RL2 of the differential pair 22 is less than about -26 dB, less than about -27 dB, less than about -28 dB, less than about -29 dB, less than about -30 dB, or less than about -31 dB. As is apparent from the curve 116 of the graph 112, for each of one or more first differential pairs of the corresponding comparative cable assembly and for each frequency in the frequency range that extends from about 10 GHz to about 30 GHz, a differential return loss of the differential pair of the corresponding comparative cable assembly is greater than about -25 dB.

[0104] FIG. 7 is a graph 118 depicting impedance versus time for the cable assembly 310 of FIG. 5A and the corresponding comparative cable assembly, according to an embodiment of the present disclosure. The time is expressed in picoseconds (ps) in the abscissa. The impedance is expressed in Ohms in the ordinate.

[0105] Referring to FIGS. 5D and 7, the graph 118 includes curves 120, 122. The curve 120 depicts impedance versus time for the cable assembly 310. The curve 122 depicts impedance versus time for the corresponding comparative cable assembly. In some embodiments, as per the curve 120, across the first length LI of each of the first insulated conductors 30, Rstd / Ravg < 0.03. In some embodiments, across the first length LI of each of the first insulated conductors 30, Rstd / Ravg < 0.25, Rstd / Ravg < 0.02, Rstd / Ravg < 0.019, or Rstd / Ravg < 0.017. Further, as per the curve 122, across the same first length LI, for the differential pairs of the corresponding comparative cable assembly, Rstd / Ravg is equal to about 0.03, which is greater than the Rstd / Ravg of the cable assembly 310. Therefore, the cable assembly 310 may have reduced impedance discontinuity in each of the first insulated conductors 30 as compared to the corresponding comparative cable assembly.

[0106] Referring to FIGS. 5A to 7, the inclusion of the electrically grounded coupling element 70a may reduce a distance between the unterminated stripped middle-section 38 and the grounded coupling element 53. This may reduce average impedance of the stripped section 35. This may further reduce the impedance discontinuity between the stripped section 35 and the unstripped section 36 of each of the first insulated conductors 30 of the cable assembly 310. This may further lead to reduced signal reflections and return loss in the cable assembly 310. Therefore, the cable assembly 310 may provide improved performance due to the reduced mode conversion and return loss.

[0107] FIG. 8A is a schematic perspective top view of a cable assembly 320, according to another embodiment of the present disclosure. FIG. 8B is a schematic top view of the cable assembly 320. FIG. 8C is a schematic side view of the cable assembly 320, with some components not shown. FIG. 8D is a schematic sectional side view of the cable assembly 320 taken along a line D-D’ shown in FIG. 8B, with some components not shown. FIG. 8E is another schematic side view of the cable assembly 320 of FIG. 8A, with some components not shown. FIG. 8F is another schematic perspective top view of the cable assembly 320, with some components not shown.

[0108] Referring to FIGS. 8A to 8F, the cable assembly 320 is substantially similar to the cable assembly 310 shown in FIGS. 5A to 5F, with common components being referred to by the same reference numerals. The functional advantage of the cable assembly 320 is substantially the same as that of the cable assembly 310. However, the cable assembly 320 includes the electrically insulative cover layer 54 (also shown in FIG. 1A) disposed on the grounded coupling element 53. The cable assembly 320 further includes an electrically grounded coupling element 70b (instead of the electrically grounded coupling element 70a shown in FIG. 5 A) disposed between the unterminated stripped middlesections 38 (shown in FIG. 8D) of the first insulated conductors 30 and the circuit board 10. In FIGS. 8C and 8D, the external jacket 21 and the electrically conductive shield 50 are not shown for illustrative purposes. In FIG. 8A, the external jacket 21 is not shown for illustrative purposes. In FIGS. 8E and 8F, the external jacket 21, the electrical first conductors 31 of the plurality of first insulated conductors 30, and the one or more first uninsulated conductors 40 are not shown for illustrative purposes.

[0109] The electrically grounded coupling element 70b is positioned so that in a plan view (shown in FIG. 8B in the x-y plane) of the cable assembly 320 in a direction (i.e., substantially along the z-axis) orthogonal to the circuit board 10, the grounded coupling element 70b covers at least 30% of the unterminated stripped middle-section 38 of each of the first insulated conductors 30. In some embodiments, the electrically grounded coupling element 70b is positioned so that in the plan view of the cable assembly 320 in the direction orthogonal to the circuit board 10, the grounded coupling element 70b covers at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, or at least 70% of the unterminated stripped middle-section 38 of each of the first insulated conductors 30.

[0110] For the reference plane P3 (i.e., the x-y plane, as shown in FIG. 8E) that is substantially parallel to the first major surface 12 of the circuit board 10 and passes through the circuit board 10 and is on the same side of the conductive pads 11 and the grounded coupling element 70b, a farthest location 1 lb (shown in FIGS. 8E and 8F) on the conductive pads 11 from the reference plane P3 that is disposed within the width of the cable set 20 is a first distance xb away from the reference plane P3. Moreover, for the planar reference plane P3, a farthest location 73b (shown in FIGS. 8E and 8F) on the grounded coupling element 70b from the reference plane P3 that is disposed within the width of the cable set 20 is a second distance yb away from the reference plane P3.

[0111] In some embodiments, the second distance yb is greater than the first distance xb by at least 1 micron. In some embodiments, the second distance yb is greater than the first distance xb by at least 2 microns, at least 3 microns, at least 4 microns, at least 5 microns, at least 10 microns, at least 15 microns, at least 20 microns, at least 50 microns, at least 75 microns, at least 100 microns, at least 150 microns, at least 200 microns, at least 250 microns, or at least 300 microns.

[0112] FIG. 9 is a schematic side view of a cable assembly 312, according to another embodiment of the present disclosure. The cable assembly 312 is substantially similar to the cable assembly 320 of FIG. 8 A, with common components being referred to as by the same numerals. However, in the cable assembly 312, the cable set 20 is tilted so that proximate the insulation-end locations 33, the unstripped sections 36 of the first insulated conductors 30 of the cable set 20 make an oblique angle b3 of greater than about 5 degrees with the first major surface 12 of the circuit board 10. In some embodiments, the oblique angle b3 is greater than about 10 degrees, greater than about 15 degrees, greater than about 20 degrees, greater than about 25 degrees, or greater than about 30 degrees.

[0113] FIG. 10 is a graph 124 depicting return loss versus frequency for the cable assembly 320 of FIG. 8A and a corresponding comparative cable assembly, according to an embodiment of the present disclosure. The cable assembly 320 and the corresponding comparative cable assembly have the same construction except that the corresponding comparative cable assembly does not include any electrically grounded coupling element (i.e., the electrically grounded coupling element 70b shown in FIG. 8A). The frequency is expressed in Gigahertz (GHz) in the abscissa. The return loss is expressed in decibels (dB) in the ordinate.

[0114] Referring to FIGS. 8A and 10, the graph 124 includes curves 126, 128. The curve 126 depicts the return loss versus frequency for the cable assembly 320. The curve 128 depicts the return loss versus frequency for the corresponding comparative cable assembly. For each of the one or more first differential pairs 22 and for at least a frequency F3 in a frequency range that extends from about 10 GHz to about 30 GHz, a differential return loss RL3 of the differential pair 22 is less than about -25 dB. In some embodiments, for at least the frequency F3 in the frequency range that extends from about 10 GHz to about 30 GHz, the differential return loss RL3 of the differential pair 22 is less than about -26 dB, less than about -27 dB, less than about -28 dB, less than about -29 dB, less than about -30 dB, less than about -35 dB, less than about -40 dB, less than about -45 dB, or less than about -47 dB.

[0115] In some embodiments, for each of the first differential pairs 22, a plot of a return loss of the first differential pair 22 versus frequency has a global minimum RL3 of less than about -30 dB in a frequency range that extends from about 5 GHz to about 50 GHz. In some embodiments, for each of the first differential pairs 22, the plot of the return loss of the first differential pair 22 versus frequency has the global minimum RL3 of less than about -35 dB, less than about -40 dB, or less than about -45 dB in the frequency range that extends from about 5 GHz to about 50 GHz.

[0116] As is apparent from the curve 128 of the graph 124, for each of one or more first differential pairs of the corresponding comparative cable assembly and for each frequency in the frequency range that extends from about 10 GHz to about 30 GHz, a differential return loss of the differential pair of the corresponding comparative cable assembly is greater than about -25 dB.

[0117] FIG. 11 is a graph 130 depicting impedance versus time for the cable assembly 320 of FIG. 8 A and the corresponding comparative cable assembly, according to an embodiment of the present disclosure. The time is expressed in picoseconds (ps) in the abscissa. The impedance is expressed in Ohms in the ordinate.

[0118] Referring to FIGS. 8D and 11, the graph 130 includes curves 132, 134. The curve 132 depicts impedance versus time for the cable assembly 320. The curve 134 depicts impedance versus time for the corresponding comparative cable assembly. In some embodiments, as per the curve 132, across the first length LI of each of the first insulated conductors 30, Rstd / Ravg < 0.03. In some embodiments, across the first length LI of each of the first insulated conductors 30, Rstd / Ravg < 0.25, Rstd / Ravg < 0.02, Rstd / Ravg < 0.015, or Rstd / Ravg < 0.01. Further, as per the curve 134, across the same first length LI, for the differential pairs of the corresponding comparative cable assembly, Rstd / Ravg is equal to about 0.03, which is greater than the Rstd / Ravg of the cable assembly 320. Therefore, the cable assembly 320 may have reduced impedance discontinuity in each of the first insulated conductors 30 as compared to the corresponding comparative cable assembly. Referring to FIGS. 8A to 11, the inclusion of the electrically grounded coupling element 70b may reduce a distance between the unterminated stripped middle-section 38 and the grounded coupling element 53. This may reduce average impedance of the stripped section 35. This may further reduce the impedance discontinuity between the stripped section 35 and the unstripped section 36 of each of the first insulated conductors 30 of the cable assembly 320. This may further lead to reduced signal reflections and return loss in the cable assembly 320. Therefore, the cable assembly 320 may provide improved performance due to the reduced mode conversion and return loss.

[0119] FIG. 12A is a schematic perspective top view of a cable assembly 330, according to another embodiment of the present disclosure. FIG. 12B is a schematic top view of the cable assembly 330. FIG. 12C is a schematic side view of the cable assembly 330, with some components not shown. FIG. 12D is a schematic sectional side view of the cable assembly 330 taken along a line E-E’ shown in FIG. 12B, with some components not shown.

[0120] The cable assembly 330 is substantially similar to the cable assembly 300 shown in FIGS. 1A to IF, with common components being referred to by the same reference numerals. The functional advantage of the cable assembly 330 is substantially the same as that of the cable assembly 300. However, in the cable assembly 330, the unterminated stripped middle-section 38 is not bent toward the first major surface 12 substantially at the insulation-end location 33. Further, the cable assembly 330 does not include an electrically insulative cover layer (i.e., the electrically insulative cover layer 54 shown inFIG. 1A) disposed onthe grounded coupling element 53. In FIGS. 12C and 12D, the external jacket 21 and the electrically conductive shield 50 are not shown for illustrative purposes. In FIG. 12A, the external jacket 21 and one of the first uninsulated conductors 40 are not shown for illustrative purposes.

[0121] Referring to FIGS. 12A to 12D, the cable assembly 330 includes an electrically grounded unitary coupling element 80 having a unitary construction and disposed on the first major surface 12 of the circuit board 10. The grounded unitary coupling element 80 includes a first portion 81 (shown in FIG. 12A) substantially parallel to the circuit board 10 and a second portion 82 (shown in FIG. 12A). The second portion 82 extends from an end 81a (shown in FIG. 12A) of the first portion 81 in a direction (i.e., substantially along the z-axis) substantially orthogonal to the circuit board 10 and defines a plurality of first through openings 83 substantially aligned with, and receiving the first conductors 31 of, the first insulated conductors 30, in a one to one correspondence.

[0122] In a plan view (shown in FIG. 12B in the x-y plane) of the cable assembly 330 in a direction (i.e., substantially along the z-axis) orthogonal to the circuit board 10, the first portion 81 covers at least 30% of the unterminated stripped middle-section 38 (shown in FIG. 12D) of each of the first insulated conductors 30. In some embodiments, in the plan view of the cable assembly 330 in the direction (i.e., substantially along the z-axis) orthogonal to the circuit board 10, the first portion 81 covers at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, or at least 70% of the unterminated stripped middle-section 38 of each of the first insulated conductors 30. In some embodiments, each of the first through openings 83 is an insulation displacement slot configured to displace some of the first insulating material 32 of the corresponding first insulated conductor 30 received therein without making physical or electrical contact with the first conductor 31 of the first insulated conductor 30. In some embodiments, the second portion 82 of the electrically grounded unitary coupling element 80 further defines a plurality of second through openings 84 (shown in FIG. 12A) substantially aligned with, and receiving the first uninsulated conductor 40 of, the one or more first uninsulated conductors 40, in a one to one correspondence. The second portion 82 makes physical and electrical contact with the first uninsulated conductor 40 of each of the one or more first uninsulated conductors 40.

[0123] FIG. 13 is a graph 136 depicting return loss versus frequency for the cable assembly 330 of FIG. 12A and a corresponding comparative cable assembly, according to an embodiment of the present disclosure. The cable assembly 330 and the corresponding comparative cable assembly have the same construction except that the corresponding comparative cable assembly does not include any electrically grounded unitary coupling element (i.e., the electrically grounded unitary coupling element 80 shown in FIG. 12A). The frequency is expressed in Gigahertz (GHz) in the abscissa. The return loss is expressed in decibels (dB) in the ordinate.

[0124] Referring to FIGS. 12A and 13, the graph 136 includes curves 138, 140. The curve 138 depicts the return loss versus frequency for the cable assembly 330. The curve 140 depicts the return loss versus frequency for the corresponding comparative cable assembly. For each of the one or more first differential pairs 22 and for at least a frequency F4 in a frequency range that extends from about 10 GHz to about 30 GHz, a differential return loss RL4 of the differential pair 22 is less than about -25 dB.

[0125] In some embodiments, for at least the frequency F4 in the frequency range that extends from about 10 GHz to about 30 GHz, the differential return loss RL4 of the differential pair 22 is less than about -26 dB, less than about -27 dB, less than about -28 dB, less than about -29 dB, less than about - 30 dB, less than about -35 dB, less than about -40 dB, less than about -45 dB, or less than about -47 dB.

[0126] In some embodiments, for each of the first differential pairs 22, a plot of a return loss of the first differential pair 22 versus frequency has a global minimum RL4 of less than about -30 dB in a frequency range that extends from about 5 GHz to about 50 GHz. In some embodiments, for each of the first differential pairs 22, the plot of the return loss of the first differential pair 22 versus frequency has the global minimum RL4 of less than about -35 dB, less than about -40 dB, or less than about -45 dB in the frequency range that extends from about 5 GHz to about 50 GHz.

[0127] As is apparent from the curve 128 of the graph 124, for each of one or more first differential pairs of the corresponding comparative cable assembly and for each frequency in the frequency range that extends from about 10 GHz to about 30 GHz, a differential return loss of the differential pair of the corresponding comparative cable assembly is greater than about -25 dB.

[0128] FIG. 14 is a graph 142 depicting impedance versus time for the cable assembly 330 of FIG. 12A and the corresponding comparative cable assembly, according to an embodiment of the present disclosure. The time is expressed in picoseconds (ps) in the abscissa. The impedance is expressed in Ohms in the ordinate.

[0129] Referring to FIGS. 12D and 14, the graph 142 includes curves 144, 146. The curve 144 depicts impedance versus time for the cable assembly 330. The curve 146 depicts impedance versus time for the corresponding comparative cable assembly. In some embodiments, as per the curve 144, across the first length LI of each of the first insulated conductors 30, Rstd / Ravg < 0.03. In some embodiments, across the first length LI of each of the first insulated conductors 30, Rstd / Ravg < 0.25, Rstd / Ravg < 0.02, Rstd / Ravg < 0.015, Rstd / Ravg < 0.01, Rstd / Ravg < 0.009, or Rstd / Ravg < 0.008. Further, as per the curve 146, across the same first lengthLl, forthe differential pairs of the corresponding comparative cable assembly, Rstd / Ravg is equal to about 0.03, which is greater than the Rstd / Ravg of the cable assembly 330.

[0130] FIG. 15 is a graph 148 depicting the impedance versus time for the cable assemblies 300, 310, 320, 330 of respective FIGS. 1A, 5A, 8A, and 12A, and their corresponding comparative cable assemblies, according to an embodiment of the present disclosure. The graph 148 shows the impedance variation for the cable assemblies 300, 310, 320, 330.

[0131] Across the first length LI of each of the first insulated conductors 30 in each of the cable assemblies 300, 310, 320, 330, Table 1 below demonstrates various parameters of impedance, such as Ravg, Rstd, Rstd / Ravg, a maximum differential impedance Rmax, a minimum differential impedance Rmin, and (Rmax - Rmin) / Ravg. Table 1 where, Cl refers to the cable assembly 300 of FIG. 1A and Cl’ refers to the corresponding comparative cable assembly;

[0132] C2 refers to the cable assembly 310 of FIG. 5A and C2’ refers to the corresponding comparative cable assembly; C3 refers to the cable assembly 320 of FIG. 8A and C3 ’ refers to the corresponding comparative cable assembly; and

[0133] C4 refers to the cable assembly 330 of FIG. 12A and C4’ refers to the corresponding comparative cable assembly.

[0134] The graph 148 (i.e., a combination of the graphs 106, 118, 130, 142) depicting the impedance variation for the cable assemblies 300, 310, 320, 330 illustrates Time Domain Reflectometry (TDR) profdes for all the cable assemblies 300, 310, 320, 330. The TDR profiles may be obtained by sending a step voltage down a test channel connected to a Device Under Test (DUT). Due to impedance discontinuities in the test channel, the step voltage may reflect at each interface where the impedance changes, such as: a transition between the unstripped section 36 and the stripped section 35 at the insulation-end location 33, the first bent portion 38a and the second bent portion 38b, the second bent portion 38b and the terminated stripped end-section 37, or the terminated stripped end-section 37 and the conductive pads 11 of the circuit board 10. The voltage reflection profiles observed may appear complicated due to initial reflections and re-reflections occurring at each interface. Additionally, the reflection behavior will appear more vague if a delay time between impedance changes is similar in magnitude to a risetime of the step voltage. This phenomena may cause the different reflections to be smeared together and be less distinct. It may be a significant reason that the TDR profiles of these different cable termination features may appear rounded and not cleanly distinguishable.

[0135] A TDR response may be measured in two ways: first, using an oscilloscope with a step generator that injects a fast risetime step and then measures the voltage that reflects back to the source end; second, measuring frequency domain scattering parameters, otherwise known as S -parameters, and then Fourier transforming into the time domain.

[0136] The above simulations were created by simulating the frequency domain differential reflection response of the cable terminations and then transforming them into the time domain.

[0137] The graphs 100, 112, 124, 136 depicting the return loss versus frequency for the cable assemblies 300, 310, 320, 330 were created showing the return loss of each of the cable assemblies 300, 310, 320, 330 using the reflected voltage observed at the cable side of the termination.

[0138] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

[0139] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and / or equivalent implementations can be substituted for the specific embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.

Claims

CLAIMS1. A cable assembly comprising: a circuit board comprising a plurality of electrically conductive pads disposed on a first major surface of the circuit board; and a cable set comprising a plurality of first insulated conductors and one or more first uninsulated conductors extending along a length, and arranged along an orthogonal width, of the cable set, at least the first insulated conductors surrounded by an electrically conductive shield, each of the first insulated conductors comprising an electrical first conductor having a cross-sectional area Al and surrounded by an electrically first insulating material, the first insulating material stripped between an insulation-end location on the first insulated conductor and a free end of the first insulated conductor to form a stripped section next to an unstripped section, the stripped section comprising a terminated stripped end-section comprising the free end and terminated at a corresponding one of the conductive pads, the terminated stripped endsection leaving a remaining unterminated stripped middle-section of the stripped section extending from the insulation-end location to the terminated stripped end-section, the unterminated stripped middle-section bent toward the first major surface substantially at the insulation-end location, such that for each of the first insulated conductors, in a first planar cross-section of the first insulated conductor that is substantially perpendicular to the circuit board and substantially bisects at least the unterminated stripped middle-section of the first insulated conductor, the unterminated stripped middle-section and the first major surface of the circuit board define a coupling region therebetween that extends laterally between the insulation-end location and the terminated stripped end-section, the coupling region having a cross-sectional area A2, A2 < 10A1.

2. The cable assembly of claim 1, wherein for each of the first insulated conductors, the bending of the unterminated stripped middle-section toward the first major surface substantially at the insulation-end location forms a first bent portion of the unterminated stripped middle-section, and wherein in the first planar cross-section of the first insulated conductor, the first bent portion makes an angle bl with a second planar cross-section of the first insulated conductor that comprises the insulation-end location and is substantially orthogonal to the first planar cross-section and the circuit board, bl < 80 degrees.

3. The cable assembly of claim 2, wherein for each of the first insulated conductors, the unterminated stripped middle-section further comprises a second bent portion that extends from an end of the first bent portion toward the first major surface, and wherein in the first planar cross-section of the first insulated conductor, the second bent portion makes an angle b2 with the second planar cross-section of the first insulated conductor, b2 > 50 degrees.

4. The cable assembly of claim 2 further comprising an electrically grounded coupling element disposed on the first major surface of the circuit board and positioned so that in a plan view of the cable assembly in a direction orthogonal to the circuit board, the grounded coupling element covers the insulation-end location and at least 30% of the first bent portion of the unterminated stripped middle-section of each of the first insulated conductors.

5. The cable assembly of claim 4 further comprising an electrically insulative cover layer disposed on the grounded coupling element and positioned to prevent the first bent portions of the unterminated stripped middle-sections of the first insulated conductors from making at least one of electrical and physical contact with the grounded coupling element.

6. The cable assembly of claim 1 further comprising an electrically grounded coupling element disposed on the first major surface of the circuit board and positioned so that in a plan view of the cable assembly in a direction orthogonal to the circuit board, the grounded coupling element covers the insulation-end location and at least 30% of the unterminated stripped middle-section of each of the first insulated conductors.

7. The cable assembly of claim 6, wherein the grounded coupling element is substantially flat.

8. The cable assembly of claim 6 further comprising an electrically insulative cover layer disposed on the grounded coupling element and positioned to prevent the unterminated stripped middlesections of the first insulated conductors from making at least one of electrical and physical contact with the grounded coupling element.

9. The cable assembly of claim 8, wherein the electrically insulative cover layer comprises a solder mask.

10. The cable assembly of claim 1 further comprising a continuous top encapsulant substantially sealing a portion of the unstripped sections of the first insulated conductors, and the entireties of the stripped sections of the first insulated conductors.

11. The cable assembly of claim 1, wherein the cable set further comprises an external jacket disposed around the first insulated conductors and the one or more first uninsulated conductors, such that the electrically conductive shield is disposed between the external jacket and the first insulated conductors and the one or more first uninsulated conductors.

12. A cable assembly comprising: a circuit board comprising a plurality of electrically conductive pads disposed on a first major surface of the circuit board; a cable set comprising a plurality of first insulated conductors and one or more first uninsulated conductors extending along a length, and arranged along an orthogonal width, of the cable set, at least the first insulated conductors of the cable set surrounded by an electrically conductive shield, each of the first insulated conductors comprising an electrical first conductor surrounded by an electrically first insulating material, the first insulating material stripped between an insulation-end location on the first insulated conductor and a free end of the first insulated conductor to form a stripped section next to an unstripped section, the stripped section comprising a terminated stripped end-section comprising the free end and terminated at a corresponding one of the conductive pads, the terminated stripped end-section leaving a remaining unterminated stripped middle-section of the stripped section extending from the insulation-end location to the terminated stripped end-section; and an electrically grounded coupling element disposed between the unterminated stripped middle-sections of the first insulated conductors and the circuit board and positioned so that in a plan view of the cable assembly in a direction orthogonal to the circuit board, the grounded coupling element covers at least 30% of the unterminated stripped middle-section of each of the first insulated conductors, wherein, for a planar reference plane that is substantially parallel to the first major surface of the circuit board and passes through the circuit board and is on a same side of the conductive pads and the grounded coupling element, a farthest location on the conductive pads from the reference plane that is disposed within the width of the cable set is a first distance away from the reference plane, and a farthest location on the grounded coupling element from the reference plane that is disposed within the width of the cable set is a second distance away from the reference plane, the second distance greater than the first distance by at least 1 micron.

13. The cable assembly of claim 12, wherein the cable set is tilted so that proximate the insulationend locations, the unstripped sections of the first insulated conductors of the cable set make an oblique angle of greater than about 5 degrees with the first major surface of the circuit board.

14. A cable assembly comprising: a cable set comprising a plurality of first insulated conductors and one or more first uninsulated conductors extending along a length, and arranged along an orthogonal width, of the cable set, at least the first insulated conductors of the cable set surrounded by an electrically conductive shield, each of the first insulated conductors comprising an electrical first conductor surrounded by an electrically first insulating material, the first insulating material stripped between an insulation-end location on the first insulated conductor and a free end of the firstinsulated conductor to form a stripped section next to an unstripped section, the stripped section comprising a terminated stripped end-section comprising the free end and terminated at a corresponding one of the conductive pads, the terminated stripped end-section leaving a remaining unterminated stripped middle-section of the stripped section extending from the insulation-end location to the terminated stripped end-section; and an electrically grounded unitary coupling element having a unitary construction and disposed on the first major surface of the circuit board, the grounded unitary coupling element comprising a first portion substantially parallel to the circuit board and a second portion extending from an end of the first portion in a direction substantially orthogonal to the circuit board and defining a plurality of first through openings substantially aligned with, and receiving the first conductors of, the first insulated conductors, in a one to one correspondence, such that in a plan view of the cable assembly in a direction orthogonal to the circuit board, the first portion covers at least 30% of the unterminated stripped middle-section of each of the first insulated conductors.

15. The cable assembly of claim 14, wherein each of the first through openings is an insulation displacement slot configured to displace some of the first insulating material of the corresponding first insulated conductor received therein without making physical or electrical contact with the first conductor of the first insulated conductor.

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