Automotive communication cables

Abstract

A communications cable is provided, comprising a pair of twisted wires, each coated with a fluoropolymer insulation. The twisted wires are configured to carry differential signals, such as differential data signals and / or differential power signals. Fluoropolymers are highly efficient insulators and significantly reduce the effects of both internal and external electromagnetic interference, while maintaining low cable attenuation (insertion loss), even when operated within a temperature range of -40°C to 150°C.

Description

Technical Field

[0001] The present disclosure relates to communication cables, and more particularly, to high temperature communication cables for the automotive industry. Background Art

[0002] The data demands of modern computer systems have continued to grow. These growing data demands are increasingly found in computer systems used in motor vehicles. To transmit data within motor vehicle computer systems, the motor vehicle industry has traditionally relied on controller area network (CAN) bus cables. Unfortunately, CAN bus cables are unable to handle the data demands of the high-bandwidth, low-latency applications (e.g., autonomous driving) required by modern and upcoming motor vehicle computer systems.

[0003] Thus, Ethernet, a common networking standard for computer systems used in buildings, is being adopted as a networking protocol for the automotive industry. The Institute of Electrical and Electronics Engineers (IEEE) 802.3 Ethernet group, the Society of Automotive Engineers (SAE), and the International Standards Organization (ISO) have developed or are in the process of developing standards for high-speed automotive vehicle networks (including the physical layer). According to these standards, automotive Ethernet networks will be interconnected via high-performance single twisted-pair cables. Unfortunately, the materials used in previously known automotive cables cannot withstand the environmental conditions within a motor vehicle while still allowing the Ethernet cables to provide sufficient data throughput to meet the data demands of modern motor vehicle computer systems.

[0004] Therefore, there is a need for new communication cables (eg, Ethernet cables) that can be used in the high temperature conditions found in motor vehicles while still meeting the high data demands of modern motor vehicle computer systems. Summary of the Invention

[0005] The present disclosure generally relates to a communications cable for use in thermally demanding environments, such as the automotive industry. In one embodiment, the cable includes twisted pairs of wires, each insulated with FEP insulation. Further embodiments may include a protective jacket surrounding the insulated twisted pairs, which protects the twisted pairs from environmental conditions and provides structural integrity to the cable.

[0006] The twisted pair cables are constructed to carry differential signals, such as differential data signals and / or differential power signals. To this end, the core of each wire is provided by a conductor to propagate the differential data and / or power signals. In each wire of the twisted pair, a wire insulation is provided that covers and surrounds the conductive core of the wire. In one embodiment, the wire insulation is formed of fluorinated ethylene propylene (FEP). These materials are highly efficient insulators and significantly reduce the effects of both internal and external electromagnetic interference, while maintaining relatively low insertion loss, even when carrying differential signals operating in the frequency range of 100 MHz to 10 GHz and the temperature range of -40°C to 150°C. In this way, the cable is able to handle the environmental conditions present under the hood of a motor vehicle while meeting the high data demands of modern motor vehicle computer systems.

[0007] The above is a simplified summary of the invention in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview. It is not intended to identify key or critical elements or to delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects of the disclosure, and together with the description, serve to explain the principles of the disclosure.

[0009] [ Figure 1 ]

[0010] Figure 1 A perspective view of an embodiment of a cable 100 according to the present disclosure is illustrated.

[0011] [ Figure 2 ]

[0012] Figure 2 Illustrated Figure 1 A cross-sectional view of an embodiment of a cable 100 is shown.

[0013] [ Figure 3 ]

[0014] Figure 3 is a table of rows and columns plotting the measured results of the dielectric constants of FEP and cross-linked polyethylene (XLPE) at temperatures of -40°C, 23°C and 105°C and frequency points of 1 GHz, 2.5 GHz, 5 GHz and 10 GHz, and at 2.5 GHz at a temperature of 150°C.

[0015] [ Figure 4 ]

[0016] Figure 4 Is drawn with Figure 3Bar chart of the same measurements.

[0017] [ Figure 5 ]

[0018] Figure 5 The change in the dielectric constant of XLPE over time when measured at a frequency of 2.5 GHz and a temperature of 150° C. is illustrated.

[0019] [ Figure 6 ]

[0020] Figure 6 is a table of rows and columns plotting the measured results of the dissipation factors of FEP and XLPE at temperatures of -40°C, 23°C and 105°C and frequencies of 1 GHz, 2.5 GHz, 5 GHz and 10 GHz, and at 2.5 GHz at a temperature of 150°C.

[0021] [ Figure 7 ]

[0022] Figure 7 It is drawn with Figure 6 Bar chart of the same measurements.

[0023] [ Figure 8 ]

[0024] Figure 8 The change in the dissipation factor of XLPE over time when measured at a frequency of 2.5 GHz and a temperature of 150° C. is illustrated.

[0025] [ Figure 9 ]

[0026] Figure 9 is a table of rows and columns that plots the measured results of the dielectric constant and dissipation factor of FEP and XLPE insulated cables based on a temperature of -40°C and the calculated results of the attenuation (insertion loss) of a single pair of cables with a cable length of 15 meters.

[0027] [ Figure 10 ]

[0028] Figure 10 Is based on Figure 9 Line plot of the same calculated single-pair cable attenuation.

[0029] [ Figure 11 ]

[0030] Figure 11 is a table of rows and columns that plots the measured results of the dielectric constant and dissipation factor of FEP and XLPE insulated cables at a temperature of 23°C and the calculated results of the attenuation of a single pair of cables with a cable length of 15 meters.

[0031] [ Figure 12 ]

[0032] Figure 12 Is based on Figure 11 Line plot of the same calculated single-pair cable attenuation.

[0033] [ Figure 13 ]

[0034] Figure 13 is a table of rows and columns that plots the measured results of the dielectric constant and dissipation factor of FEP and XLPE insulated cables at a temperature of 105°C and the calculated results of the attenuation of a single pair of cables with a cable length of 15 meters.

[0035] [ Figure 14 ]

[0036] Figure 14 Is based on Figure 13 Line plot of the same calculated single-pair cable attenuation.

[0037] [ Figure 15 ]

[0038] Figure 15 is a table of rows and columns that plots the measured results of the dielectric constant and dissipation factor of FEP and XLPE at a temperature of 105°C and the calculated results of the attenuation of a single pair cable with a cable length of 100 meters.

[0039] [ Figure 16 ]

[0040] Figure 16 Is based on Figure 15 Line plot of the same calculated attenuation.

[0041] [ Figure 17 ]

[0042] Figure 17 A communication cable according to an embodiment is schematically illustrated.

[0043] [ Figure 18 ]

[0044] Figure 18 An exemplary test apparatus is schematically illustrated.

[0045] [ Figure 19 ]

[0046] Figure 19 is a line graph showing the insertion loss (cable attenuation) of a representative automotive communication cable at different temperatures and frequencies.

[0047] [ Figure 20 ]

[0048] Figure 20is a graph illustrating the insertion loss of an FEP insulated cable at various temperatures and frequencies according to one embodiment.

[0049] [ Figure 21 ]

[0050] Figure 21 is a table showing rows and columns of insertion loss values ​​measured at various temperatures and frequencies for an FEP insulated cable according to one embodiment.

[0051] [ Figure 22 ]

[0052] Figure 22 is a line graph showing the insertion loss of 15 meter long cables with different insulation at 23°C.

[0053] [ Figure 23 ]

[0054] Figure 23 is a graph showing the insertion loss of 15 meter long cables with different insulation after being kept at 125° C. for 3 hours.

[0055] [ Figure 24 ]

[0056] Figure 24 is a graph showing the insertion loss of 15 meter long cables with different insulation after being kept at 125° C. for 4 hours.

[0057] [ Figure 25 ]

[0058] Figure 25 is a line graph showing the insertion loss of 15 meter long cables with different insulation at 23°C and ambient relative humidity.

[0059] [ Figure 26 ]

[0060] Figure 26 is a line graph showing the insertion loss of 15 meter long cables with different insulations after being kept at 85° C. and 85% relative humidity for 3 hours.

[0061] [ Figure 27 ]

[0062] Figure 27 is a line graph showing the insertion loss of 15 meter long cables with different insulations after being kept at 85° C. and 85% relative humidity for 168 hours.

[0063] [ Figure 28 ]

[0064] Figure 28is a table showing rows and columns of insertion loss values ​​for various cables at high temperatures over a range of frequencies.

[0065] [ Figure 29 ]

[0066] Figure 29 is a table showing rows and columns of insertion loss values ​​for various cables at high temperature and high humidity over a range of frequencies. DETAILED DESCRIPTION

[0067] The embodiments set forth below represent the necessary information to enable those skilled in the art to implement the present disclosure and illustrate the best mode of practicing the present disclosure. When reading the following description in light of the accompanying drawings, those skilled in the art will understand the concepts of the present disclosure and will recognize applications of these concepts not specifically mentioned herein. It should be understood that these concepts and applications fall within the scope of the present disclosure and the appended claims.

[0068] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the specification and should not be interpreted in an idealized or overly formal sense unless explicitly defined herein. For the sake of brevity or clarity, well-known functions or structures may not be described in detail.

[0069] The terms "about" and "approximately" shall generally refer to an acceptable degree of error or variation in a measured quantity given the nature or precision of the measurement results. Typical, exemplary degrees of error or variation are within 20 percent (%) of a given value or range of values, preferably within 10%, and more preferably within 5%. Unless otherwise noted, numerical quantities given in this specification are approximate, meaning that the term "about" or "approximately" can be inferred when not explicitly mentioned. Numerical quantities in the claims are exact unless otherwise noted.

[0070] It will be understood that when a feature or element is referred to as being "on" another feature or element, it can be directly on the other feature or element, or there can be intervening features and / or elements. Conversely, when a feature or element is referred to as being "directly on" another feature or element, there are no intervening features or elements. It will also be understood that when a feature or element is referred to as being "connected," "attached," or "coupled" to another feature or element, it can be directly connected, attached, or coupled to the other feature or element, or there can be intervening features or elements. Conversely, when a feature or element is referred to as being "directly connected," "directly attached," or "directly coupled" to another feature or element, there are no intervening features or elements. Although described or illustrated with respect to one embodiment, the features and elements so described or illustrated may apply to other embodiments.

[0071] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0072] The terms "first," "second," etc., are used herein to describe various features or elements, but these features or elements should not be limited by these terms. These terms are only used to distinguish one feature or element from another. Thus, without departing from the teachings of the present disclosure, a first feature or element discussed below could be referred to as a second feature or element, and similarly, a second feature or element discussed below could be referred to as a first feature or element.

[0073] Terms such as “at least one of A and B” should be understood to mean “only A, only B, or both A and B.” The same interpretation should apply to longer lists (eg, “at least one of A, B, and C”).

[0074] The term "consisting essentially of" means that, in addition to the enumerated elements, the claimed content may also include other elements (steps, structures, ingredients, components, etc.) that do not adversely affect the operability of the claimed content for its intended purpose as stated in the present disclosure. The term does not include such other elements that do not adversely affect the operability of the claimed content for its intended purpose as stated in the present disclosure, even if such other elements may enhance the operability of the claimed content for some other purpose.

[0075] Reference is made in some places to standard methods, such as but not limited to measurement methods. It is understood that such standards are revised from time to time and, unless explicitly mentioned otherwise, references to such standards in this disclosure must be construed as references to the most recently issued standards as of the time of filing.

[0076] This disclosure describes embodiments of communication cables, such as Ethernet cables. The cables are particularly well-suited for automotive computer systems exposed to high temperatures but experiencing increasing data demands. One specific embodiment of the cable includes a single twisted pair of wires. The wire insulation for each of these wires is provided by a high-insulation, low-attenuation, and heat-resistant material, such as FEP. The twisted pairs are constructed to carry differential data and / or power signals. Using FEP as the wire insulation allows the cable to transmit differential signals within a high-frequency range (e.g., 100 MHz-10 GHz) while being able to handle the more extreme thermal conditions presented by automotive vehicles. It should be noted that other embodiments of the cable may include several pairs of wires to provide multiple paths for differential data and / or power signals. Other embodiments of the cable include more than one twisted pair of wires. Specific embodiments of the cable include at least one, two, three, or four twisted pairs of wires. Further specific embodiments of the cable include exactly one, two, three, or four twisted pairs of wires. These pairs of wires may be inserted into a cable jacket that provides structural integrity to the Ethernet cable. In some embodiments, cables having more than one twisted pair incorporate a separator within the cable. In some embodiments, embodiments having exactly one twisted pair do not incorporate a separator within the cable. Additionally, in some embodiments, the cable can be shielded to help protect the cable from electromagnetic interference.

[0077] Figure 1 illustrates a perspective view of an embodiment of a cable 100 according to the present disclosure, and Figure 2 Illustrated Figure 1 1. The cable 100 includes a pair of wires 102, 104 twisted together to form a twisted pair 102, 104. The wire 102 includes a conductor 106 (see FIG. Figure 2 ), and line 104 includes conductor 108 (see Figure 2 ), conductors 106 and conductors 108 are each formed from a conductive material. The conductive material forming conductors 106, 108 can be any conductive material, including elemental metals, alloys, and the like. In one embodiment, conductors 106, 108 in wires 102, 104 are each formed from copper. In some implementations, a pair of conductors 106, 108 can be used to propagate differential signals, such that conductors 106, 108 carry complementary signals that are approximately 180 degrees out of phase. Thus, the pair of wires 102, 104 are twisted together to help eliminate electromagnetic interference between the wires 102, 104 and maintain a balanced pair of conductors 106, 108. In one implementation, the pair of wires 102, 104 is used to handle both data signaling and power transmission. For example, the pair of wires 102, 104 can be used to deliver up to 50 watts of power to sensors and active communication devices.

[0078] like Figure 1 and Figure 2 As shown, wires 102, 104 each further include wire insulation (insulators) 110, 112. Wire insulation 110 of wire 102 surrounds and covers conductor 106, while wire insulation 112 of wire 104 surrounds and covers conductor 108. In some embodiments, the wire insulation creates a substantially airtight seal around the conductors. In some embodiments, the wire insulation is in direct contact with the conductors and forms a substantially airtight seal between the insulation and the conductors. In some embodiments, the insulation is in direct contact with the entire circumference and length of the conductors. It will be understood that a small portion of the conductor length may be inserted into connector 118 and may not be in direct contact with the insulation.

[0079] The wire insulation 110 and the wire insulation 112 are formed of an insulating material with a low dielectric constant, which has a low permittivity and therefore resists the concentration of electromagnetic flux lines when there are high charges and currents. This allows a pair of wires 102, 104 to propagate high-frequency signals. In one implementation, the cable 100 is a Category 6A Ethernet cable, which requires the cable 100 to be able to carry signals with operating frequencies between 10 MHz and 500 MHz and a system throughput of up to 10 gigabits per second (Gbps) while minimizing external noise effects and internal crosstalk sources such as near-end crosstalk (NEXT) and far-end crosstalk (FEXT). Examples of suitable forms of Category 6A cable 100 include unshielded twisted pair (UTP), segmented shielded twisted pair (SSTP), and shielded twisted pair (STP). A suitable form of STP includes a shield having polyethylene terephthalate (PET) on one side and aluminum on the other side, and a drain line. One suitable form of SSTP comprises a shield having polyethylene terephthalate (PET) on one side and aluminium on the other, wherein the aluminium is cut at regular intervals and the PET is whole along the length of the shield, thereby avoiding the need for a discharge wire.

[0080] In some embodiments, the insulating material forming wire insulation 110 and wire insulation 112 has a dielectric constant of between about 1.2 and about 2.1 at temperatures experienced under the hood of a modern automobile engine. Typically, these temperatures range from -40°C to 200°C. In another embodiment, the insulating material forming wire insulation 110 and wire insulation 112 has a dielectric constant of between about 1.5 and about 2.1 at temperatures experienced under the hood of a modern automobile engine. In yet another embodiment, the insulating material forming wire insulation 110 and wire insulation 112 has a dielectric constant of between about 1.7 and about 2.1 at temperatures experienced under the hood of a modern automobile engine.

[0081] FEP offers several advantages, including good performance over a wide temperature range, a high melting point, high solvent resistance, high acid and alkali resistance, high water and oil resistance, low friction, and high stability. An example of a suitable FEP is CAS Registry No. 25067-11-2. FEP is a melt-processable copolymer of hexafluoropropylene and tetrafluoroethylene (TFE). Unlike PFA and some other fluoropolymers, every carbon in FEP is saturated with fluorine atoms. The general formula of the TFE subunit is -(CF2CF2)-, while the general formula of the hexafluoropropylene subunit is -(CF2CF(CF3))-.

[0082] The fluoropolymers may be in foamed or solid form. In one embodiment, the fluoropolymer has a foamed structure. In this regard, the fluoropolymer may further include a medium to promote foaming. For example, the fluoropolymer may include a nucleating agent. Suitable additives include, but are not limited to, boron nitride; inorganic salts such as calcium tetraborate, sodium tetraborate, potassium tetraborate, calcium carbonate, zinc tetraborate, and barium nitrate; talc; and metal oxides such as magnesium oxide, aluminum oxide, and silicon dioxide. In one embodiment, the fluoropolymer includes boron nitride.

[0083] The foamed fluoropolymers described herein, such as FEP, are suitable for use in the insulation material forming wire insulation 110 and wire insulation 112. In one embodiment, when the insulation material is composed of the foamed fluoropolymer, the insulation material has a dielectric constant between about 1.2 and about 1.7. In another embodiment, when the insulation material is composed of the foamed fluoropolymer, the insulation material has a dielectric constant between about 1.4 and about 1.6. In yet another embodiment, when the insulation material is composed of the foamed fluoropolymer, the insulation material has a dielectric constant between about 1.4 and about 1.5.

[0084] The insulation of each wire may be at least 95% w / w fluoropolymer. In another embodiment, each wire may be at least 95%, 96%, 97%, 98%, 99%, 99.9% or 100% fluoropolymer.

[0085] In some embodiments, the insulating material may include additives, modifiers, or enhancers. For example, the insulating material may be colored or include a colorant for identification purposes. In some embodiments, the insulating material includes a metal passivator, a UV stabilizer, and / or a copper stabilizer. In some embodiments, the insulating material is free of polar additives and / or substantially free of all additives.

[0086] It should be noted that other embodiments of the cable 100 may be provided as different types of Ethernet cables, such as Category 5e, Category 6, Category 7, Category 7A, and Category 8. Alternative embodiments of the cable 100 may be provided as other types of Ethernet cables, including 100BASE-T1 cables. Some Ethernet standards that different examples of the cable 100 may comply with include IEEE 802.3cg, IEEE 802.3bw, IEEE 802.3bp, IEEE 802.3ch, and IEEE 802.3bu Ethernet standards. Additionally, some cable standards include SAE J3117 / 1, SAE J3117 / 2, and SAE J3117 / 3.

[0087] [Example]

[0088] Figure 1 and Figure 2 The embodiment of the cable 100 shown in FIG includes a shield 114 and a cable jacket 116 that surround the wires 102, 104 carrying differential data and / or power signals along the length of the cable 100. In this example, the shield 114 is disposed between the wires 102, 104 and the cable jacket 116. The shield 114 is configured to reflect EMI and / or conduct EMI safely to ground. In either case, the shield 114 helps prevent EMI from affecting the conductors 106, 108 in the wires 102, 104. Therefore, even if some EMI passes through the shield 114, it is highly attenuated and does not significantly interfere with the data and / or power signals being transmitted along the conductors 106, 108 of the wires 102, 104. In some embodiments, the shield 114 is in direct contact with the wires 102, 104 and forms a substantially airtight seal between the shield and the wires 102, 104. In some embodiments, the shield 114 is in direct contact with the perimeter and length of the wires 102, 104. It will be appreciated that a small portion of the length of the wires 102, 104 may be inserted into the connector 118 and may not be in direct contact with the shield 114.

[0089] In this example, the shield 114 is provided as a braid, which can be formed into a woven mesh of a metal such as copper. Thus, the shield 114 can provide a highly conductive path to ground. This embodiment of the cable 100 is an example of a shielded twisted pair (STP). In some implementations, the cable 100 is up to 40 meters long and is particularly suitable for use in large trucks. In an alternative example, the shield 114 can be provided as a foil shield, which can be formed from a thin layer of metal such as aluminum. The foil shield can be attached to a carrier (which can be formed from a material such as polyester) to increase strength and robustness. In other examples, the cable 100 can include multiple concentric shields, which are particularly useful in very noisy environments. In other examples, the cable 100 can be unshielded, so that there is no shield 114 between the jacket 116 and the wires 102, 104. This would be an example of an unshielded twisted pair (UTP) cable. In some implementations, a UTP cable can be up to 15 meters long and is particularly useful in standard consumer cars.

[0090] Figure 1 and Figure 2 The embodiment of the cable 100 shown also includes a jacket 116, which forms the outermost layer of the cable 100 and is exposed to the external environment. In some embodiments, the jacket 116 surrounds one or both of the shield 114 and the wires 102, 104. In this way, the jacket 116 is constructed to protect the shield 114, the insulation 110, 112 and the conductors 106, 108 from EMI, external physical forces, heat and chemical degradation. The jacket 116 can be formed by any suitable material such as polyvinyl chloride (PVC), polyurethane (PUR), chlorinated polyethylene (CPE), XLPE, ethylene propylene rubber (EPR), FEP, PFA or ethylene tetrafluoroethylene (ETFE). In some alternative examples, fillers, plasticizers, activators and inhibitors can be added to the jacket 116 to enhance the specific physical, electrical or chemical properties of the jacket 116. In some embodiments, the jacket 116 is in direct contact with the shield 114 and forms a substantially airtight seal between the jacket 116 and the shield 114. In some embodiments, the jacket 116 is in direct contact with the entire circumference and length of the shield 114. It should be understood that a small portion of the length of the shield 114 may be inserted into the connector 118 and may not be in direct contact with the jacket 116.

[0091] Figure 1The illustrated embodiment of the cable 100 includes a connector 118 connected at one end 120 of the cable 100. More specifically, the connector 118 includes a pair of conductive members 122, 124, wherein corresponding ends (not shown) of the conductors 106 of the wire 102 are connected to the conductive members 122, and corresponding ends (not shown) of the conductors 108 of the wire 104 are connected to the conductive members 124. The conductive members 122, 124 can provide differential input / output ports for the cable 100, so that differential data and / or power signals propagating through the wires 102, 104 can be input into and / or output from the cable 100. The connector 118 also includes a connector housing 126 that houses the pair of conductive members 122, 124. The shield 114 and the jacket 116 are terminated and internally attached within the housing 126. The housing 126 also includes an insertable portion that surrounds the conductive members 122 , 124 and can be inserted into an opposite connector (not explicitly shown) so that data and / or power differential signals can be input into and / or output from the cable 100 .

[0092] It should be noted that in this example, the connector 118 is a male differential connector because a pair of conductive members 122, 124 provide male connections to input or output data and / or power differential signals. In an alternative embodiment, the connector 118 can be a female connector and thus include a pair of conductive channels configured to receive a male differential connector. Additionally, in this embodiment of the cable 100, no further connector, such as the connector 118, is provided at the other end 128 of the cable 100. Instead, connections to the conductors 106, 108 can be provided directly at the end 128 of the cable 100. However, in an alternative embodiment, another connector, such as the connector 118, is connected to the end 128 of the cable 100.

[0093] As further detailed below, Figures 3 to 8 The electrical advantages of using FEP as insulation 110 , 112 over traditional insulation materials used in the automotive industry, such as, for example, XLPE or polypropylene, are illustrated.

[0094] To determine the electrical measurements, a resonant cavity perturbation technique is used. More specifically, a resonant cavity perturbation technique described as ASTM D2520 Method B is performed in a frequency range between 1 GHz and 10 GHz. A resonant cavity is provided and connected to an oscilloscope. To determine the electrical properties of a material, the material is placed in the resonant cavity. When the material is placed in the resonant cavity, the resonant cavity is perturbed by the change in permittivity or permeability caused by the material. The change in permittivity or permeability is detected by measuring the frequency response of the resonant cavity in the presence and absence of the material. The change in the frequency response of the resonant cavity due to the material (e.g., the change in resonant frequency) can then be determined to calculate the electrical properties of the material.

[0095] In some examples, the dielectric constant and dissipation factor of FEP and XLPE were measured at temperatures of -40°C, 23°C, and 105°C, and frequencies of 1 GHz, 2.5 GHz, 5 GHz, and 10 GHz. The dielectric constant and dissipation factor of FEP and XLPE were measured at 150°C and 2.5 GHz, as this is likely higher than the average temperature experienced under the hood of a motor vehicle. Unless otherwise noted, the average of three samples was measured at each frequency, and the test values ​​were obtained after a 15-minute material stabilization period.

[0096] Figure 3 and Figure 4 is a graph plotting measurement results of dielectric constants of FEP and XLPE at temperatures of -40°C, 23°C, and 105°C and frequency points of 1 GHz, 2.5 GHz, 5 GHz, and 10 GHz, and at a temperature of 150°C at 2.5 GHz. Figure 3 is a table of rows and columns of text, and Figure 4 is a bar graph showing the measurement results of dielectric constant. Dielectric constant is the ratio of the absolute dielectric constant of a material to the dielectric constant of a vacuum. Therefore, the lower the dielectric constant, the higher the ability of the material to attenuate electric fields. Figure 3 and Figure 4 As shown in Figure 2, the dielectric constant of FEP is consistently lower than that of XLPE at all frequencies and temperatures. In addition, the dielectric constant of FEP exhibits very little variation compared to that of XLPE at all frequencies and temperatures.

[0097] Another advantage of FEP is that the dielectric constant of FEP remains relatively consistent over time, even at 150°C. While the dielectric constant of XLPE remains relatively consistent over time at 105°C, the dielectric constant of XLPE does not remain consistent over time at 150°C. Figure 5 More specifically, Figure 5 The change in the dielectric constant of XLPE over time when measured at a frequency of 2.5 GHz and a temperature of 150° C. is illustrated. Figure 5 As shown, after an initial drop from approximately 2.14 to 2.12, the dielectric constant of XLPE increases to nearly 2.24 within a span of just over 4 hours.

[0098] Figure 6 and Figure 7 is a graph of measurement results of dissipation factors of FEP and XLPE at temperatures of 23° C., −40° C., and 105° C. and frequency points of 1 GHz, 2.5 GHz, 5 GHz, and 10 GHz, and at a temperature of 150° C. at 2.5 GHz. Figure 6 is a form of rows and columns of text, and Figure 7 is a bar graph showing the results of dissipation factor measurements. The dissipation factor of a material is the inverse of its quality factor. The quality factor is equal to the ratio of the absolute value of susceptance to the absolute value of conductance. Therefore, the dissipation factor is a measure of the rate of energy loss from vibrational modes in a material. Therefore, the lower the dissipation factor, the higher the material's ability to dissipate energy oscillations. Figure 6 and Figure 7 As shown, the dissipation factor of FEP is generally lower than that of XLPE at all frequencies and temperatures. This indicates that FEP performs better (e.g., less signal or power is lost along the length of the line) when compared to XLPE.

[0099] An advantage of FEP over XLPE is that, unlike the dissipation factor of XLPE, the dissipation factor of FEP remains relatively consistent over time. Figure 8 This is exemplified in . More specifically, Figure 8 The figure shows the change in the dissipation factor of XLPE over time when measured at a frequency of 2.5 GHz and a temperature of 150°C. Figure 8 As shown in Figure 2, after initially dropping to just above zero, the dissipation factor increases to over 0.01000 within a span of nearly 4 hours. Another experiment was conducted at 23°C, where the dissipation factor of XLPE was 0.000337 before the experiment and 0.000505 afterward. This represents a 50% increase in dissipation factor, which is significant in high-frequency Ethernet cable applications.

[0100] From the above Figures 3 to 8 From the test data, it can be seen that FEP is a stable material at 150°C compared to XLPE.

[0101] XLPE is just one example of a wire insulation material commonly used in the automotive industry. While XLPE has good dielectric properties at -40°C and 23°C, XLPE is not thermally and electrically stable enough to be used as insulation for wires in Ethernet cables for automotive applications at temperatures of 105°C or higher.

[0102] Given experimental information on the dielectric constant and dissipation factor, the single-pair cable attenuation (insertion loss) of lines 102, 104 can be calculated using the following formula:

[0103] [Formula 1]

[0104]

[0105] Where A is the attenuation (dB), L is the length of the cable 100 (m), f is the frequency (in multiples of Hertz, i.e., MHz or GHz), and the parameters a, b, and c can be derived from the dielectric constant and dissipation factor.

[0106] More specifically, "I / L" is a length correction factor or linear adjustment for cable lengths other than 100m. For example, if the cable is 15m, the attenuation value will be 15 / 100 or 15% of the 100m value. Parameter "a" includes the dielectric constant (DC) of the insulating material plus an adjustment factor from the 2.75 standard (derived from the channel requirements of Multi-Gigabit Ethernet (IEEE802.3ch)) and a copper factor including AWG, conductivity, and strand factor. For the purposes of this disclosure, 24AWG bare copper is used for calculations. Parameter "b" includes the dissipation factor (DF) or loss tangent (tanδ) of the insulating material plus an adjustment factor from the 0.005 standard. Parameter "c" affects the attenuation at low frequencies. This term is a calculated adjustment that takes into account how parameters such as skin effect, inductance, and conductor roundness affect the attenuation calculation. In some embodiments, because the attenuation is evaluated at high frequencies (up to 10GHz), this term will have minimal impact.

[0107] Figure 9 and Figure 10 The graph plots the measured results of the dielectric constant and dissipation factor of cables insulated with FEP and XLPE at a temperature of -40°C and the calculated results of the attenuation of a single pair of cables with a cable length of 15 meters. Figure 9 is a table of rows and columns of text, and Figure 10 is a line graph showing the calculation results of cable attenuation. Figure 9 The frequency band of cable attenuation values ​​is highlighted between 1 GHz and 10 GHz, wherein the cable attenuation values ​​of the FEP insulated cable are highlighted with a box.

[0108] Calculations show that the single-pair attenuation of FEP-insulated cables is 0.4dB to 1.5dB lower than that of XLPE-insulated cables between 1GHz and 10GHz. The calculated electrical performance advantage of FEP-insulated cables at -40°C is due to the low dielectric constant and dissipation factor of FEP at -40°C.

[0109] Figure 11 and Figure 12The graph plots the measured results of the dielectric constant and dissipation factor of cables insulated with FEP and XLPE at a temperature of 23°C and the calculated results of the attenuation of a single pair of cables with a cable length of 15 meters. Figure 11 is a table of rows and columns of text, and Figure 12 This is a line graph showing the calculated results of cable attenuation. Figure 11 A frequency band of cable attenuation values ​​is highlighted between 1 GHz and 10 GHz, with the cable attenuation values ​​for FEP insulated cables highlighted with a box.

[0110] Calculations show that the single-pair cable attenuation of FEP-insulated cables is 0.4dB to 1.5dB better than that of XLPE-insulated cables between 1GHz and 10GHz. The calculated electrical performance advantage of FEP-insulated cables at 23°C is due to the lower dielectric constant and dissipation factor of FEP at 23°C.

[0111] Figure 13 and Figure 14 The graph plots the measured results of the dielectric constant and dissipation factor of FEP and XLPE insulated cables at a temperature of 105°C and the calculated results of the attenuation of a single pair of cables with a cable length of 15 meters. Figure 13 is a table of rows and columns of text, and Figure 14 This is a line graph showing the calculated results of cable attenuation. Figure 13 The frequency band of cable attenuation values ​​is highlighted between 1 GHz and 10 GHz. At a temperature of 105°C, the calculation becomes more challenging due to the instability of the dissipation factor of XLPE. Therefore, the dissipation factor measured after a four-hour period is used, as this corresponds to a worst-case scenario. On the other hand, the dielectric constant of cross-linked FEP is stable, so this presents no problem.

[0112] Plugging the dielectric constant and dissipation factor measured at 10 GHz for both FEP and XLPE into the above attenuation equation, the single-pair attenuation advantage of cables insulated with FEP over XLPE in the 1 GHz to 10 GHz band ranges from 0.4 dB to 1.6 dB, which is similar to the performance advantages observed for FEP and XLPE at -40°C and 23°C.

[0113] Figure 15 and Figure 16 The graph plots the measured results of the dielectric constant and dissipation factor of cables insulated with FEP and XLPE at a temperature of 105°C and the calculated results of the cable attenuation with a cable length of 100 meters. Figure 15 is a table of rows and columns of text, and Figure 16 This is a line graph showing the calculation results of attenuation. Figure 15The frequency band of cable attenuation values ​​is highlighted between 1 GHz and 10 GHz. Figure 15 and Figure 16 The results shown in Figure 13 and Figure 14 To demonstrate the effect of cable length, we compare the results in

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[62] , [6 Figure 13 and Figure 14 The calculation results in Figure 15 and Figure 16 By comparing the calculated results in FIG, it can be seen that the attenuation advantage of the cable insulated with FEP over the cable insulated with XLPE increases to 2.6 dB at 1 GHz at a temperature of 105°C and increases to 10.8 dB at 10 GHz. Therefore, providing insulation to the wires 102, 104 of the cable 100 provides the automotive industry with significant and meaningful cable attenuation advantages over previously known insulation materials (e.g., XLPE). Specifically, Figures 9 to 16 It is shown that when FEP is used to provide the insulation (shields) 112 , 114 of the wires 102 , 104 , the dielectric properties of the FEP make a significant difference in the single-pair cable attenuation characteristics of the cable 100 .

[0114] In addition to testing polymers as described above, functional cables were fabricated according to embodiments of the disclosed invention to allow for additional analysis. The cables were each 15 meters in length.

[0115] like Figure 17 As schematically illustrated in FIG, a single twisted pair cable is made using a pair of 22 AWG copper wires. Each copper wire is insulated with FEP wire insulation. The FEP insulated wires are contained within an FEP inner jacket, a foil shield, a braided aluminum shield, and an outer jacket.

[0116] A second single twisted pair cable was manufactured in substantially the same construction, except that the second single twisted pair cable incorporated XLPE instead of FEP for the wire insulation and inner jacket. XLPE insulated single twisted pair cables are considered representative automotive Ethernet cables.

[0117] like Figure 18 As schematically illustrated in FIG, the test equipment is configured to measure the insertion loss of a manufactured cable. The test is performed in accordance with the OPEN Alliance Insertion Loss (Cable Attenuation) test method, including the OPEN Alliance Channel and Component Requirements for 1000BASE-T1 Link Segment Type Av2.0 - Section 6.1.2 Cable Requirements (SCC Context). The insertion loss equation used is,

[0118] [Table 1]

[0119]

[0120] The test equipment includes a vector network analyzer (Rohde & Schwarz ZNB-8) and a temperature chamber (Tenney TJR).

[0121] A test fixture was soldered to the end of each manufactured cable to mate the tested cable with measurement and test equipment using SMA connectors. The 15-meter-long cable under test was placed in a temperature chamber in a loose coil configuration, with approximately 12 inches of cable at each end exposed through sealed side access ports. The exposed ends were connected to the test equipment. Both FEP-insulated and XLPE-insulated cables were tested using the same test equipment to determine the cable's insertion loss over a range of frequencies and temperatures.

[0122] During the test process, the cable was coiled in a temperature chamber, and the cable's insertion loss was measured at 23°C (room temperature). The temperature in the temperature chamber was raised to the target temperature over a one-hour period. The temperature in the test chamber was then held at the target temperature for one hour to ensure that the cable's temperature had reached the target temperature. The cable's insertion loss was then measured at the target temperature. The same process was then followed, with the temperature in the temperature chamber raised to the next target temperature. The three target temperatures examined in this particular example were 85°C, 105°C, and 125°C. Once the insertion loss was measured at these three target temperatures, the temperature in the temperature chamber was ramped down to 23°C over a one-hour period. The temperature in the temperature chamber was then held at 23°C for one hour to ensure that the cable's temperature had reached 23°C. The cable's insertion loss was measured a second time at 23°C. Comparing the cable's insertion loss at 23°C before and after the heating process is useful to ensure that the cable and / or insulation have not degraded and / or the cable's electrical performance has not degraded after the cable was heated.

[0123] Figure 19 The results of insertion loss tests of a representative XLPE coated automotive Ethernet cable are shown. Figure 19 As shown, the insertion loss at the test conditions of 85°C, 105°C, and 125°C is each worse than the test condition at the typically lower temperature.

[0124] Figure 20 The results of the insertion loss test of the above-mentioned FEP insulated cable are shown as an example. Figure 20 As shown, the insertion loss under test conditions of 85°C, 105°C, and 125°C is generally similar to the insertion loss at lower temperatures. Additionally, compared to a representative automotive cable, the insertion loss of the FEP-insulated cable decreases as the signal frequency increases. Therefore, the FEP-insulated cable has less insertion loss at higher temperatures (e.g., temperatures above 80°C) and has lower insertion loss than a representative automotive cable at all tested temperatures.

[0125] Typical automotive cables are insulated with XLPE blends. XLPE blends contain additives designed to protect the polymer material from environmental factors, including, for example, contact with copper, solvent or corrosive fluids, high and low temperatures, and UV light. At least some of these additives are structurally polar molecules that vibrate more as the temperature of the additive molecules and the surrounding matrix increases. Without being bound by theory, it is believed that the increased vibration of these polar molecules affects the dissipation factor of the XLPE, thereby reducing the insertion loss performance of typical automotive cables as temperature rises.

[0126] FEP-insulated cables are insulated with an FEP polymer that does not contain any polar additives. FEP has physical and mechanical properties that make it suitable for use in wire and cable applications without the need for polar additives. Without being bound by theory, it is believed that the insertion loss performance of FEP-insulated cables is generally maintained at higher temperatures, in part because the polymer does not contain polar additives that increase the dissipation factor at higher temperatures.

[0127] Figure 21 This table shows the measured insertion loss values ​​for FEP-insulated cables over a range of temperatures, compared to the Open Alliance TC9 specification for Automotive Ethernet channels and components, over the frequency range of 1 MHz to 600 MHz. The table shows that the measured insertion loss of the FEP-coated cables outperforms the TC9 standard at all frequencies and temperatures. The difference between the TC9 standard and the measured insertion loss of the FEP-coated cables increases with increasing frequency and also with increasing temperature. The table shows that the insertion loss of the FEP-insulated cables increases with increasing frequency and temperature, but never exceeds 8.5 dB. This insertion loss is below the temperature-adjusted TC9 threshold.

[0128] The tests described herein revealed that XLPE-insulated cables performed worse than expected in real-life simulations, compared to initially calculated insertion loss performance expectations. Conversely, FEP-insulated cables performed better than expected in these examples, relative to initially calculated insertion loss performance expectations. Without wishing to be bound by theory, it is believed that the primary cause of insertion loss in FEP-insulated cables is due to the inherent decrease in copper conductivity with increasing temperature, while FEP has little negative impact.

[0129] Figures 22 to 27 Illustrate the use of Figure 17 Data was collected for cables similar to the one shown, but constructed using 26AWG 7 / 34 copper conductors instead of 22AWG 7 / 30 copper conductors. Wire insulation was FEP, PP, or XLPE, depending on the cable, and the inner jacket was made of cross-linked polyolefin (XLPO). All cables were 15 meters in length.

[0130] Figures 22 to 24 The example illustrates the testing of three similarly constructed cables against the TC9 insertion loss limits used by the SAE J3117 / 2 and ISO 19642-12 draft specifications for 1000BASE-T1 cables. The cables being tested are identical except that the wire insulation is either FEP, XLPE, or PP. Each cable is initially tested for insertion loss at 23°C. Each cable is then tested again for insertion loss after being held at 125°C for three hours. Each cable is then tested a third time for insertion loss after being held at 125°C for a total of 240 hours. Figure 22 As shown, all three cables initially passed the TC9 insertion loss performance standard when the cables were tested at 23°C over the frequency range of 1MHz to 600MHz.

[0131] from Figure 23 It can be seen that after the cable has been kept at 125℃ for 3 hours, the insertion loss of the PP insulated cable is lower than the TC9 standard. After the FEP insulated cable and the XLPE insulated cable have been kept at 125℃ for 3 hours, the insertion loss in the frequency range of 1MHz to 600MHz has passed the TC9 standard. Figure 23 As shown, under these test conditions, FEP insulated cable has lower insertion loss than XLPE insulated cable.

[0132] from Figure 24 It can be seen that after being kept at 125℃ for 240 hours, the electrical performance of both FEP insulated cables and XLPE insulated cables have passed the TC9 standard in the frequency range of 1MHz to 600MHz. Figure 24 As shown in Figure 3, as the frequency increases, the FEP insulated cable exhibits smaller insertion loss than the XLPE insulated cable.

[0133] Figures 25 to 27 Illustrated is the insertion loss testing of three similarly constructed cables as they are subjected to high temperature and humidity. Figures 22 to 24 The cables described are identical. Each cable was initially tested for insertion loss at 23°C and ambient relative humidity. Each cable was then tested for insertion loss again after being held at 85°C and 85% relative humidity for 3 hours. Each cable was tested for insertion loss a third time after being held at 85°C and 85% relative humidity for a total of 168 hours. Figure 25 As shown, all three cables initially exceeded the TC9 insertion loss performance standard when the cables were tested over the 1MHz to 600MHz frequency range at 23°C and ambient relative humidity.

[0134] from Figure 26It can be seen that after the cables are kept at 85℃ and 85% relative humidity for 3 hours, the insertion loss of the PP insulated cable is lower than the TC9 standard. After being kept at 85℃ and 85% relative humidity for 3 hours, the insertion loss of both the FEP insulated cable and the XLPE insulated cable passed the TC9 standard in the frequency range of 1MHz to 600MHz. Figure 26 As shown, under these test conditions, the insertion loss of FEP insulated cable is lower than that of XLPE insulated cable.

[0135] like Figure 27 As shown, after being kept at 85° C. and 85% relative humidity for 168 hours, the insertion loss of both the FEP insulated cable and the XLPE insulated cable passed the TC9 standard in the frequency range of 1 MHz to 600 MHz.

[0136] Figure 28 It shows Figures 22 to 24 Table of rows and columns of the measured insertion loss values ​​discussed in . Figure 28 The measured insertion loss values ​​for 15 m cables insulated with PP, XLPE and FEP at 23°C, 125°C after 3 hours and at 125°C after 240 hours are shown. Figure 28 It can be seen that the FEP insulated cable has lower insertion loss than the other cables. This difference increases at higher frequencies.

[0137] Figure 29 It shows that Figures 25 to 27 Table of rows and columns of measured insertion loss values ​​discussed in . Figure 29 The measured insertion loss values ​​for 15 m cables insulated with PP, XLPE and FEP are shown at 23°C and ambient humidity, after three hours at 85°C and 85% relative humidity, and after 168 hours at 85°C and 85% relative humidity. Figure 29 It can be seen that the FEP insulated cable has a smaller insertion loss than the other cables, and this difference increases at higher frequencies.

[0138] Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the present disclosure. All such improvements and modifications are considered to be within the scope of the concepts disclosed herein and the appended claims. It is to be understood that any given element of the embodiments disclosed herein may be implemented as a single structure, a single step, a single substance, etc. Similarly, a given element of the disclosed embodiments may be implemented as multiple structures, steps, substances, etc.

[0139] The foregoing description illustrates and describes the processes, machines, manufacture, material compositions and other teachings of the present disclosure. Additionally, the present disclosure only shows and describes certain embodiments of the disclosed processes, machines, manufacture, material compositions and other teachings, but, as mentioned above, it is to be understood that, commensurate with the skills and / or knowledge of those skilled in the relevant art, the teachings of the present disclosure can be used in various other combinations, modifications and environments, and can be changed or modified within the scope of the teachings as expressed herein. The embodiments described above are further intended to explain certain known best modes for practicing the processes, machines, manufacture, material compositions and other teachings of the present disclosure, and to enable other technicians in the field to utilize the teachings of the present disclosure in such or other embodiments, and with various modifications required for specific applications or uses. Therefore, the processes, machines, manufacture, material compositions and other teachings of the present disclosure are not intended to limit the exact embodiments and examples disclosed herein. Any section titles provided herein are merely for consistency with the recommendations of 37 CFR § 1.77 or to provide an organizational queue in other ways. These titles should not limit or characterize the inventions described herein.

Claims

1. An automotive communication cable, comprising: a single twisted pair conductor comprising a first conductor insulated by a first insulation layer and a second conductor insulated by a second insulation layer, wherein the first insulation layer and the second insulation layer are in contact with the associated conductor along the entire periphery of the conductor, and wherein the first insulation layer and the second insulation layer comprise at least 95% w / w fluorinated ethylene propylene (FEP); and an outer sheath surrounding the twisted pair of conductors, Each of the first insulating layer and the second insulating layer has a dielectric constant between 1.7 and 2.1 in a temperature range of -40°C to 150°C and a frequency range of 1 GHz to 10 GHz.

2. The communication cable according to claim 1, wherein At least one of the first insulating layer and the second insulating layer forms a hermetic seal with an associated conductor.

3. The communication cable according to claim 1, wherein The first insulating layer and the second insulating layer do not contain polar additives.

4. The communication cable according to claim 1, wherein The first and second insulating layers are at least 99% w / w FEP and contain no additives.

5. The communication cable of claim 1, further comprising a shielding layer surrounding the first insulation layer and the second insulation layer of the single twisted pair conductor. The communication cable according to claim 1 , wherein: The cable is an Ethernet cable.

7. The communication cable according to claim 1, wherein The cable is configured to transmit differential signals in the range of 10 MHz to 10 GHz.

8. The communication cable according to claim 1, wherein The cable has an insertion loss of less than 10 dB at 15 meters in a temperature range of 0° C. to 105° C. and a frequency range of 1 MHz to 400 MHz.

9. The communication cable according to claim 1, wherein The cable has an insertion loss of less than 7 dB over a temperature range of -40°C to 125°C and a frequency range of 10 MHz to 400 MHz at a length of 15 meters.

10. The communication cable according to claim 1, wherein The cable has an insertion loss of less than 10 dB at 15 meters in a temperature range of -40°C to 125°C and a frequency range of 10 MHz to 600 MHz.

11. The communication cable according to claim 1, wherein The cable has an insertion loss of less than 8.5 dB over a temperature range of -40°C to 125°C and a frequency range of 10 MHz to 600 MHz at a length of 15 meters.

12. The communication cable according to claim 1, wherein The cable has an insertion loss at least 5 dB less than the Open Alliance TC9 standard at 105° C. and 400 MHz.

13. The communication cable according to claim 1, wherein The cable has an insertion loss at 125° C. and 600 MHz that is at least 8 dB less than an allowable insertion loss of the Open Alliance TC9 standard.

14. The communication cable according to claim 1, wherein The cable includes 26 AWG copper wire and has an insertion loss of less than 17.5 dB over a temperature range of 23° C. to 125° C. and a frequency range of 100 MHz to 1 GHz at 15 meters.

15. The communication cable according to claim 1, wherein The cable has an insertion loss of less than 16.5 dB at 15 meters over a temperature range of 23° C. to 125° C. and a frequency range of 100 MHz to 1 GHz.

16. The communication cable according to claim 1, wherein The cable has an insertion loss of less than 14.5 dB at 15 meters in a temperature range of 23° C. to 125° C. and a frequency range of 100 MHz to 800 MHz.

17. The communication cable according to claim 1, wherein The cable has an insertion loss of less than 12.5 dB over a temperature range of 23° C. to 125° C. and a frequency range of 100 MHz to 600 MHz at 15 meters.

18. The communication cable according to claim 1, wherein Each of the first conductor and the second conductor is formed of copper.

19. The communication cable according to claim 1, wherein Each of the first insulating layer and the second insulating layer has a dielectric constant of 1.990 or greater in a temperature range of -40°C to 150°C and in a frequency range of 1 GHz to 10 GHz.

20. A motor vehicle comprising a cable according to any one of claims 1 to 19.

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