WO2021129870A1 - 传输线缆 - Google Patents

传输线缆 Download PDF

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Publication number
WO2021129870A1
WO2021129870A1 PCT/CN2020/140109 CN2020140109W WO2021129870A1 WO 2021129870 A1 WO2021129870 A1 WO 2021129870A1 CN 2020140109 W CN2020140109 W CN 2020140109W WO 2021129870 A1 WO2021129870 A1 WO 2021129870A1
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WO
WIPO (PCT)
Prior art keywords
dispersion
section
transmission
positive
negative
Prior art date
Application number
PCT/CN2020/140109
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English (en)
French (fr)
Inventor
李昆
张鲁奇
吕瑞
刘余
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP20904828.9A priority Critical patent/EP4060390A4/en
Publication of WO2021129870A1 publication Critical patent/WO2021129870A1/zh
Priority to US17/849,630 priority patent/US20220334306A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P9/00—Delay lines of the waveguide type
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
    • G02B6/4401—Optical cables
    • G02B6/4429—Means specially adapted for strengthening or protecting the cables
    • G02B6/443—Protective covering
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/02—Optical fibres with cladding with or without a coating
    • G02B6/02214—Optical fibres with cladding with or without a coating tailored to obtain the desired dispersion, e.g. dispersion shifted, dispersion flattened
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4274—Electrical aspects
    • G02B6/4277—Protection against electromagnetic interference [EMI], e.g. shielding means
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/25—Arrangements specific to fibre transmission
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29379—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device
    • G02B6/29392—Controlling dispersion
    • G02B6/29394—Compensating wavelength dispersion

Definitions

  • This application relates to the field of communication interconnection, and in particular to a transmission cable technology applicable to terahertz and millimeter wave bands.
  • AOC Active Optical Cables
  • DAC Direct Attach Cable
  • TAC Terahertz active cable
  • CMOS Complementary Metal Oxide Semiconductor
  • TAC Terahertz active cable
  • It is a carrier wave and a polymer transmission line as the transmission medium.
  • It is a new type of interconnection that can be used in data centers, which is different from AOC and DAC.
  • the existing TAC has the characteristic of changing with the change of the diameter and length due to its dispersion characteristics, and at the same time, it has poor dispersion characteristics in the working frequency band, and the total group delay of the in-band transmission is relatively large. Therefore, exploring TAC with low dispersion and low group delay has great application prospects in data center scenarios that meet the growth of massive data.
  • the present application provides a transmission cable, which can solve the problem of large group delay in existing cables applied to terahertz and millimeter wave bands.
  • a transmission cable including at least one periodic structure, the periodic structure including a positive dispersion transmission section, a negative dispersion transmission section, a positive and negative dispersion matching section, and a negative positive dispersion matching section; the positive dispersion transmission
  • the dispersion coefficient of the segment is positive, the dispersion coefficient of the negative dispersion transmission segment is negative, the cross-sectional diameter of the positive dispersion transmission segment is smaller than the cross-sectional diameter of the negative dispersion transmission segment;
  • the positive-negative dispersion matching segment is used for Connect the positive dispersion transmission section and the negative dispersion transmission section, the other end of the negative dispersion transmission section is connected to the negative positive dispersion matching section, or the other end of the positive dispersion transmission section is connected to the negative positive dispersion matching segment.
  • the positive dispersion transmission section and the negative dispersion transmission section at periodic intervals can cancel each other chromatic dispersion, thereby reducing the total group delay, and can meet the demand for massive data transmission in a data center scenario.
  • the cross-sectional diameter D p of the positive dispersion transmission section and the cross-sectional diameter D n of the negative dispersion transmission section satisfy the following relationship:
  • ⁇ 1 is the relative permittivity of the periodic structure
  • c is the speed of light in vacuum
  • f c is the lowest operating frequency in the operating frequency band.
  • the dispersion coefficient C p of the positive dispersion transmission section and the dispersion coefficient C n of the negative dispersion transmission section are the same in magnitude and opposite in sign.
  • the positive dispersion transmission section and the negative dispersion transmission section of the same length can be selected, so that the total group delay of the two transmission sections is close to 0, and compared with the situation where the length of each section is different, the dispersion coefficient is also different, the signal The working bandwidth in the transmission cable is larger, and the processing consistency is better.
  • the length of each segment of the four-segment structure included in the periodic structure is not less than Where ⁇ 1 is the relative permittivity of the periodic structure, c is the speed of light in vacuum, and f c is the lowest operating frequency in the operating frequency band.
  • the four-segment length in the periodic structure meets the above requirements, can achieve lower reflectivity, and reduce signal transmission loss in the transmission cable.
  • each section of the four-section structure can be An integer multiple of, of course, it can also be any one or more lengths of Integer multiples of.
  • the length of the positive dispersion transmission section and the length of the negative dispersion transmission section can both be n is a positive integer, that is, the multiples of the two transmission sections are the same; the length of the positive and negative dispersion matching section and the length of the negative positive dispersion matching section can also be both m is a positive integer, that is, the multiple of the two matching segments is the same. Normally, the length is The reflection parameter of the cable will be smaller and the design will be simpler.
  • the transmission cable further includes a shielding layer that wraps the periodic structure and is used for shielding external electromagnetic interference.
  • the shielding layer can be a dielectric foam shielding layer or a metal shielding layer.
  • the material of the dielectric foam shielding layer should be a dielectric material with a relative dielectric constant lower than the dielectric core and a lower loss tangent, such as PTFE foam;
  • the metal shielding layer can be Choose metal materials with excellent electromagnetic shielding effect and high conductivity, such as copper foil, aluminum foil, tin foil, etc.
  • the shielding layer is a dielectric foam shielding layer, wherein the relative permittivity of the dielectric foam shielding layer is less than the relative permittivity ⁇ of the periodic structure 1.
  • the electric field of the signal can be more concentrated in the inner core to reduce radiation loss; or, the shielding layer is a metal shielding layer, wherein the conductivity of the metal shielding layer is not less than 1 ⁇ 10 7 seconds/meter (s /m); Since the higher the conductivity of the metal, the lower the loss of the signal. Therefore, meeting the conditions of this embodiment can reduce the loss of the signal in the transmission cable.
  • the dispersion coefficient C p and the length L p of the positive dispersion transmission section, the dispersion coefficient C n and the length L n of the negative dispersion transmission section, and the dispersion of the positive and negative dispersion matching section satisfy the following relationship:
  • the total group delay of each periodic structure is 0, which is the optimal situation. It can ensure that the positive and negative dispersion can be canceled in the periodic structure. In actual situations, there may be some deviations. The possible deviations caused by factors such as environment and cable aging should also be within the protection scope of this application.
  • the dispersion coefficient C p and the length L p of the positive dispersion transmission section, the dispersion coefficient C n and the length L n of the negative dispersion transmission section, and the dispersion of the positive and negative dispersion matching section satisfy the following relationship:
  • the length of the positive dispersion transmission section and the negative dispersion transmission section are the same, the magnitude of the dispersion coefficient is the same, and the sign is opposite; the positive and negative dispersion matching section and the negative positive dispersion matching section are also the same length, the magnitude of the dispersion coefficient is the same, and the sign is opposite.
  • the working bandwidth of the signal in the transmission cable is larger, and it has better processing consistency.
  • the diameter of the connecting surface between the positive and negative dispersion matching section and the positive dispersion transmission section is the same as the cross-sectional diameter of the positive dispersion transmission section, and the positive and negative dispersion matching section
  • the diameter of the connecting surface between the negative dispersion transmission section and the negative dispersion transmission section is the same as the cross section diameter of the negative dispersion transmission section, wherein the cross section diameter of the positive and negative dispersion matching section is uniformly gradual or stepped.
  • the diameter of the connecting surface between the negative and positive dispersion matching section and the negative dispersion transmission section is the same as the cross-sectional diameter of the negative dispersion transmission section, and the negative and positive dispersion matching section
  • the diameter of the connecting surface between the positive dispersion transmission section and the positive dispersion transmission section in the next periodic structure is the same as the cross section diameter of the positive dispersion transmission section, wherein the cross section diameter of the negative positive dispersion matching section is uniformly gradual or Stepped jump.
  • the matching structure can also adopt several forms such as parabolic gradation, hyperbolic gradation, Chebyshev curve gradation and so on.
  • the material of the periodic structure includes any one of polytetrafluoroethylene, polypropylene, polyethylene, high-density polyethylene (HDPE), and polystyrene.
  • the periodic structure is a section of transmission cable that includes two transmission sections and two matching sections. Any of the above materials can be used. The above materials have lower loss in millimeter wave and terahertz wave bands, which is beneficial to the frequency in millimeters. The transmission of signals in the wave and terahertz band.
  • a transmission cable including a positive dispersion transmission section, a negative dispersion transmission section, and a dispersion matching section; the dispersion coefficient of the positive dispersion transmission section is positive, and the dispersion coefficient of the negative dispersion transmission section is Negative, the cross-sectional diameter of the positive dispersion transmission section is smaller than the cross-sectional diameter of the negative dispersion transmission section, wherein the dispersion matching section is used to connect the positive dispersion transmission section and the negative dispersion transmission section.
  • the transmission cable provided by the embodiment of the present application includes a positive dispersion transmission section and a negative dispersion transmission section, which can cancel each other chromatic dispersion, thereby reducing the total group delay, and can meet the demand for massive data transmission in a data center scenario.
  • the cross-sectional diameter D p of the positive dispersion transmission section and the cross-sectional diameter D n of the negative dispersion transmission section satisfy the following relationship:
  • ⁇ 1 is the relative permittivity of the periodic structure
  • c is the speed of light in vacuum
  • f c is the lowest operating frequency in the operating frequency band.
  • the dispersion coefficient C p of the positive dispersion transmission section and the dispersion coefficient C n of the negative dispersion transmission section are the same in magnitude and opposite in sign.
  • the positive dispersion transmission section and the negative dispersion transmission section of the same length can be selected, so that the total group delay of the two transmission sections is close to 0, and compared with the situation where the length of each section is different, the dispersion coefficient is also different, the signal The working bandwidth in the transmission cable is larger, and the processing consistency is better.
  • the dispersion matching section includes a positive and negative dispersion matching section and a negative positive dispersion matching section, wherein the positive and negative dispersion matching section is used to connect the positive dispersion transmission section and the negative dispersion matching section.
  • the other end of the negative dispersion transmission section is connected to the negative and positive dispersion matching section, or the other end of the positive dispersion transmission section is connected to the negative and positive dispersion matching section.
  • the transmission cable includes a plurality of periodic structures, and the periodic structure includes a positive dispersion transmission section, a negative dispersion transmission section, a positive and negative dispersion matching section, and a negative positive dispersion matching section.
  • the periodic structure includes a positive dispersion transmission section, a negative dispersion transmission section, a positive and negative dispersion matching section, and a negative positive dispersion matching section.
  • the lengths of the positive dispersion transmission section, the negative dispersion transmission section, and the dispersion matching section are not less than
  • ⁇ 1 is the relative permittivity of the transmission cable
  • c is the speed of light in vacuum
  • f c is the lowest operating frequency in the operating frequency band.
  • the transmission section or the matching section meets the above requirements, can achieve lower reflectivity, and reduce the transmission loss of the signal in the transmission cable.
  • the length of each of the positive dispersion transmission section, the negative dispersion transmission section, and the dispersion matching section is equal to Integer multiples of.
  • the length of the positive dispersion transmission section and the length of the negative dispersion transmission section can both be n is a positive integer, that is, the multiples of the two transmission sections are the same; the length of the positive and negative dispersion matching section and the length of the negative positive dispersion matching section can also be both m is a positive integer, that is, the multiples of the two matching segments are the same.
  • the length is The reflection parameter of the cable will be smaller and the design will be simpler.
  • the transmission cable further includes a shielding layer that wraps the positive dispersion transmission section, the negative dispersion transmission section, and the dispersion matching section, and is used to shield external electromagnetic waves. interference.
  • the shielding layer can be a dielectric foam shielding layer or a metal shielding layer.
  • the material of the dielectric foam shielding layer should be a dielectric material with a relative dielectric constant lower than the dielectric core and a lower loss tangent, such as PTFE foam; the metal shielding layer can be Choose metal materials with excellent electromagnetic shielding effect and high conductivity, such as copper foil, aluminum foil, tin foil, etc.
  • the shielding layer is a dielectric foam shielding layer, wherein the relative permittivity of the dielectric foam shielding layer is smaller than the relative permittivity ⁇ 1 of the transmission cable, which can make the signal The electric field is more concentrated in the inner core to reduce radiation loss; or, the shielding layer is a metal shielding layer, wherein the conductivity of the metal shielding layer is not less than 1 ⁇ 10 7 seconds/meter (s/m); due to the metal The higher the conductivity, the smaller the loss of the signal. Therefore, meeting the conditions of this embodiment can reduce the loss of the signal in the transmission cable.
  • the dispersion coefficient C p and the length L p of the positive dispersion transmission section, the dispersion coefficient C n and the length L n of the negative dispersion transmission section, and the dispersion of the positive and negative dispersion matching section satisfy the following relationship:
  • the total dispersion of the four segments is lower than the positive dispersion transmission segment with the same length, or the negative dispersion transmission segment with the same length, which can achieve the effect of canceling positive and negative dispersion.
  • the dispersion coefficient C p and the length L p of the positive dispersion transmission section, and the dispersion coefficient C n and the length L n of the negative dispersion transmission section satisfy the following relationship:
  • the length of the positive dispersion transmission section and the negative dispersion transmission section are the same, the magnitude of the dispersion coefficient is the same, and the signs are opposite.
  • the working bandwidth of the signal in the transmission cable is larger, and it has better processing consistency. It should be understood that a certain error in the size of the dispersion coefficient is also within the protection scope of this application.
  • the diameter of the connecting surface between the dispersion matching section and the positive dispersion transmission section is the same as the cross-sectional diameter of the positive dispersion transmission section, and the dispersion matching section and the negative
  • the diameter of the connecting surface between the dispersion transmission sections is the same as the cross-sectional diameter of the negative dispersion transmission section, wherein the cross-sectional diameter of the dispersion matching section is uniformly gradual or stepped.
  • the matching structure can also adopt several forms such as parabolic gradation, hyperbolic gradation, Chebyshev curve gradation and so on.
  • the materials of the positive dispersion transmission section, the negative dispersion transmission section, and the dispersion matching section include polytetrafluoroethylene, polypropylene, polyethylene, high-density polyethylene (HDPE), and polystyrene. Any of ethylene.
  • the above-mentioned materials have lower losses in the millimeter wave and terahertz bands, and are beneficial to the transmission of signals with frequencies in the millimeter wave and terahertz bands.
  • a transmission cable system in a third aspect, includes a radio frequency chip, a baseband signal processing chip, an electromagnetic coupling structure, and the transmission in any one of the possible implementation manners of the first aspect or the second aspect. Cable; wherein the baseband signal processing chip is electrically connected to the radio frequency chip, the radio frequency chip is also connected to the electromagnetic coupling structure, and the electromagnetic coupling structure is connected to the transmission cable.
  • the transmission cable system provided in this embodiment can be applied to scenarios requiring massive data transmission such as data centers to play a role in interconnection and intercommunication.
  • the radio frequency chip includes a radio frequency transmitting chip and a radio frequency receiving chip
  • the electromagnetic coupling structure includes a first electromagnetic coupling structure and a second electromagnetic coupling structure
  • the transmission cable includes a first transmission The cable and the second transmission cable
  • the baseband processing chip is used to receive service signals, and send the signals to the radio frequency transmitter chip after processing
  • the radio frequency transmitter chip performs up-conversion processing on the received signal and processes
  • the latter signal is coupled to the first transmission cable through the first electromagnetic coupling structure, and is transmitted through the first transmission cable
  • the second transmission cable is used to receive signals and pass the received signals through
  • the second electromagnetic coupling structure is coupled to the radio frequency receiving end chip.
  • the radio frequency receiving end chip performs down-conversion processing on the received signal, and sends the processed signal to the baseband signal processing chip.
  • the baseband signal The processing chip is used to demodulate the received signal.
  • the transmission cable system further includes a packaging structure for packaging the radio frequency chip, the baseband signal processing chip, and the electromagnetic coupling structure.
  • the packaging structure can play the role of dust protection, and can adapt to the standard interface in the network, and the interconnection and intercommunication between devices can be realized without changing the device interface.
  • the transmission cable provided by the embodiment of the present application includes transmission sections with different cross-sectional dimensions and respectively having positive and negative dispersion characteristics, and the two transmission sections corresponding to the two cross-sectional sizes are connected through the matching section, so that the In the working frequency band, partial or full cancellation of positive and negative dispersion is realized. Under the premise of ensuring excellent transmission characteristics, the total group delay and the influence of dispersion on the signal are greatly reduced.
  • Figure 1 is a schematic diagram of the interconnection inside the data center
  • Figure 2 is a transmission cable provided by an embodiment of the application
  • FIG. 3 is a schematic diagram of a matching structure in a transmission cable provided by another embodiment of this application.
  • FIG. 4 is a schematic diagram of a matching structure in a transmission cable provided by another embodiment of this application.
  • FIG. 5 is a transmission cable system provided by another embodiment of this application.
  • FIG. 6 is a diagram of a simulation result of a group delay characteristic of a transmission cable provided by another embodiment of the present application.
  • FIG. 7 is a diagram of S parameter simulation results of a transmission cable provided by another embodiment of the present application.
  • FIG. 8 is a diagram of a simulation result of a loss characteristic of a transmission cable provided by another embodiment of the present application.
  • FIG. 9 is a schematic diagram of a matching structure in a transmission cable provided by another embodiment of the present application.
  • FIG. 10 is a diagram of a simulation result of a group delay characteristic of a transmission cable provided by another embodiment of the present application.
  • FIG. 11 is a diagram of S parameter simulation results of a transmission cable provided by another embodiment of the present application.
  • FIG. 12 is a diagram showing the simulation results of the loss characteristics of the transmission cable provided by another embodiment of the present application.
  • FIG. 13 is a transmission cable provided by another embodiment of this application.
  • FIG. 14 is a diagram of S parameter simulation results of a transmission cable provided by another embodiment of the present application.
  • FIG. 15 is a diagram of a simulation result of a loss characteristic of a transmission cable provided by another embodiment of the present application.
  • FIG. 16 is a transmission cable provided by another embodiment of this application.
  • FIG. 17 is a transmission cable provided by another embodiment of this application.
  • FIG. 18 is a transmission cable provided by another embodiment of this application.
  • the application provides a transmission cable technology.
  • the cable has the characteristics of low dispersion and low group delay, can realize the signal transmission in the terahertz and millimeter wave bands, and can meet the data interconnection requirements in the growing data center scene.
  • the transmission cable includes at least one periodic structure 200.
  • the periodic structure 200 includes a positive dispersion transmission section 201, a negative dispersion transmission section 202, and a positive and negative dispersion matching section 203.
  • the negative-positive dispersion matching section 204 wherein the positive dispersion transmission section 201 has a positive dispersion coefficient, the negative dispersion transmission section 202 has a negative dispersion coefficient, and the cross-sectional diameter of the positive dispersion transmission section 201 is smaller than that of the negative dispersion transmission section 202.
  • the diameter, that is, the positive dispersion transmission section 201 is thinner than the negative dispersion transmission section 202.
  • the specific connection method is shown in Figure 2.
  • One end of the positive dispersion transmission section 201 is connected to one end of the positive and negative dispersion matching section 203, and the other end of the positive and negative dispersion matching section 203 is connected to one end of the negative dispersion transmission section 202.
  • the other end is connected to the positive dispersion transmission section of the next periodic structure.
  • the positive dispersion transmission section 201, the negative dispersion transmission section 202, the positive and negative dispersion matching section 203, and the negative positive dispersion matching section 204 are all a section of the transmission cable
  • the periodic structure 200 is the transmission cable including the above four sections;
  • the structure 200 is used for dispersion cancellation, which can reduce the total group delay.
  • the periodic structure includes a negative dispersion transmission section, a negative positive dispersion matching section, a positive dispersion transmission section, and a positive and negative dispersion matching section that are connected in sequence; or starting with a negative and positive dispersion matching section, the periodic structure includes a negative and positive dispersion matching section connected in sequence , Positive dispersion transmission section, positive and negative dispersion matching section and negative dispersion transmission section; or starting from the positive and negative dispersion matching section, the periodic structure includes the positive and negative dispersion matching section, the negative dispersion transmission section, and the negative positive dispersion matching section connected in sequence And positive dispersion transmission section. Any of the above division methods are within the protection scope of this application.
  • the transmission cable includes at least one periodic structure 200 disclosed in the present application, that is, within the protection scope of the present application, the transmission cable is not required to include only the periodic structure 200; for example, the transmission cable transmits a section with positive dispersion.
  • the beginning includes 100 periodic structures 200 as shown in Figure 2 and a positive dispersion transmission section as the end; or the transmission cable starts with a negative dispersion transmission section, including a negative dispersion transmission section, a negative positive dispersion matching section, and 100 periodic structures 200 as shown in Figure 2; or the transmission cable starts with a negative dispersion transmission section, including a negative dispersion transmission section, a negative positive dispersion matching section, 100 periodic structures 200 as shown in Figure 2, and one as For the finished positive dispersion transmission section, the several possible arrangements mentioned above are all within the protection scope of this application.
  • transmission cables with positive and negative dispersion characteristics and different cross-sectional dimensions are periodically arranged at intervals, and two transmission sections corresponding to the two cross-sectional dimensions are respectively connected through matching sections, thereby realizing the
  • the beneficial effect of partial or full cancellation of positive and negative dispersion in the working frequency band greatly reduces the total group delay and reduces the influence of dispersion on the signal.
  • the length of each segment of the four-segment structure included in the periodic structure 200 is not less than That is not less than the waveguide wavelength, where ⁇ 1 is the relative permittivity of the material used in the periodic structure 200, c is the speed of light in vacuum, fc is the lowest operating frequency in the operating frequency band, that is, f c is the fundamental mode of the signal capable of transmitting The minimum operating frequency transmitted in the cable, signals with a frequency lower than fc will not be transmitted.
  • the four-segment length in the periodic structure meets the above requirements, can achieve lower reflectivity, and reduce signal transmission loss in the transmission cable.
  • each segment of the four-segment structure can be an integer multiple of the waveguide wavelength, of course, the length of any one or more segments can also be an integer multiple of the waveguide wavelength.
  • the length of the positive dispersion transmission section and the length of the negative dispersion transmission section can both be n times the waveguide wavelength, n is a positive integer, that is, the multiples of the two transmission sections are the same; the length of the positive and negative dispersion matching section matches the negative positive dispersion
  • the length of the segments can also be m times the waveguide wavelength, and m is a positive integer, that is, the multiples of the two matching segments are the same. Under normal circumstances, the length is an integer multiple of the waveguide wavelength, the reflection parameter of the cable will be smaller, and the design is simpler.
  • the positive dispersion in the transmission section 201 of the cross-sectional diameter D p and a negative dispersion in the transmission section of the cross-sectional diameter D 202 n satisfies the following relationship:
  • a signal with a frequency not less than f c can be transmitted in the transmission cable disclosed in the present application, and the signal can realize the interaction of positive and negative dispersion in the transmission cable, thereby reducing the dispersion and dispersion of the signal in the transmission cable.
  • the total group delay can be transmitted in the transmission cable disclosed in the present application, and the signal can realize the interaction of positive and negative dispersion in the transmission cable, thereby reducing the dispersion and dispersion of the signal in the transmission cable.
  • the total group delay of the positive dispersion transmission section is equal to the product of the dispersion coefficient C p of the positive dispersion transmission section and the length L p
  • the total group delay of the negative dispersion transmission section is equal to The product of the dispersion coefficient C n and the length L n of the negative dispersion transmission section.
  • the total group delay of the positive and negative dispersion matching section is equal to the product of the dispersion coefficient C 1 and the length L 1 of the positive and negative dispersion matching section.
  • the total group delay is equal to the product of the dispersion coefficient C 2 and the length L 2 of the negative positive dispersion matching segment; the total group delay of the four segments can satisfy the following relationship:
  • each periodic structure is 0, which is the optimal situation. It can ensure that the positive and negative dispersion can be canceled in the periodic structure. In actual situations, there may be some deviations, depending on the process or external environment. The possible deviations caused by factors such as cable aging should also be within the protection scope of this application.
  • the sum of the total group delay of the positive dispersion transmission section and the total group delay of the negative dispersion transmission section is 0, and the sum of the total group delay of the positive and negative dispersion matching section and the total group delay of the negative positive dispersion matching section The sum is 0. It should be understood that the total group delay of 0 should also include possible deviations caused by factors such as process, external environment, cable aging, and so on.
  • the length L p of positive dispersion transmission segment may be equal to the length of negative dispersion transmission segment L n
  • positive and negative dispersion matched segment length L 1 may be equal to the length L 2 negative positive dispersion matched segment
  • positive dispersion dispersion coefficient transmission segment C p is the same size as the dispersion coefficient C n of the negative dispersion transmission section, and has opposite signs
  • the dispersion coefficient C 1 of the positive and negative dispersion matching section is the same size as the dispersion coefficient C 2 of the negative positive dispersion matching section, and the sign is opposite.
  • the dispersion coefficients referred to in the embodiments of the present application are the same, and do not need to be exactly the same.
  • the dispersion coefficients due to factors such as process errors, cable aging, etc. have a slight deviation, which should also be within the protection scope of the embodiments of the present application.
  • the transmission cable provided in this application has a cross-sectional diameter of about At this time, the dispersion coefficient of the signal whose operating frequency is near f c is close to zero.
  • the transmission cable can use low-loss polymer materials as the core material of the transmission cable, that is, the periodic structure can be made of polymer materials, for example, the polymer material can be selected as polytetrafluoroethylene.
  • the polymer material can be selected as polytetrafluoroethylene.
  • PTFE Polytetra fluoroethylene
  • PP polypropylene
  • PE polyethylene
  • HDPE high-density polyethylene
  • PS polystyrene
  • the Hertz band has a low-loss dielectric material.
  • the transmission cable can be a solid-core dielectric transmission line, that is, only a solid-core polymer material; it can also use a polymer as an inner core and wrap a shielding layer outside the solid-core polymer material, that is, Wrap the periodic structure with a shielding layer to shield external electromagnetic interference and improve signal transmission performance; among them, the shielding layer can be a dielectric foam shielding layer or a metal shielding layer.
  • the material of the dielectric foam shielding layer should be a dielectric material with a relative dielectric constant lower than that of the dielectric core and a lower loss tangent, such as PTFE foam; the metal shielding layer can be selected from a metal material with excellent electromagnetic shielding effect and high conductivity , Such as copper foil, aluminum foil, tin foil, etc.
  • the shielding layer is a dielectric foam shielding layer
  • the relative permittivity of the dielectric foam shielding layer is smaller than the relative permittivity ⁇ 1 of the periodic structure, so that the electric field of the signal is more concentrated in the inner core and the radiation loss is reduced;
  • the shielding layer is a metal shielding layer
  • the metal needs to be a good conductor. The higher the conductivity of the metal, the smaller the loss of the signal. Normally, the conductivity of the metal shielding layer is not less than 1 ⁇ 10 7 seconds/m ( s/m).
  • the cross-sectional diameter of the positive dispersion transmission section in the periodic structure is small, while the cross-sectional diameter of the negative dispersion transmission section is larger.
  • the positive and negative dispersion transmission sections cannot be directly connected, and must be matched
  • the segment structures are connected, and the matching segment can be a uniformly gradual structure as shown in FIG. 3 or a stepped jump type structure as shown in FIG. 4.
  • the uniformly graded structure can achieve better impedance matching, less reflection, and can reduce signal transmission loss; while the step-jump structure has the advantage of simple technology.
  • This application does not limit the number of steps of the step-jump structure.
  • the length of the truncated steps can be the same.
  • Figure 4 is an example of three steps. The fewer the steps, the simpler the process; the more the steps, the closer the shape will be to a uniform gradient.
  • the matching section may also adopt parabolic gradients, hyperbolic gradients, Chebyshev curve gradients and other forms to achieve positive and negative dispersion cross-sections.
  • the matching connection between the two is not limited in this application.
  • the positive and negative dispersion matching section and the negative positive dispersion matching section in the periodic structure are both located between the positive dispersion transmission section and the negative dispersion transmission section, and are used to connect the two transmission sections. The only difference lies in the signal transmission direction.
  • the dispersion matching section is used to carry from the positive dispersion transmission section to the negative dispersion transmission section
  • the negative positive dispersion matching section is used to carry from the negative dispersion transmission section to the positive dispersion transmission section; among them, the difference between the positive and negative dispersion matching section and the positive dispersion transmission section
  • the diameter of the connecting surface is the same as the cross-sectional diameter of the positive dispersion transmission section
  • the diameter of the connecting surface between the positive and negative dispersion matching section and the negative dispersion transmission section is the same as the cross section diameter of the negative dispersion transmission section; similarly, the negative positive dispersion matching
  • the cross-sectional diameters at both ends of the segment also meet the above conditions.
  • the structure of the positive and negative dispersion matching segment and the negative positive dispersion matching segment can be the same. As shown in Figure 3 or 4, the two matching segments are equivalent to each other rotated by 180 degrees; one of the matching segments can also use one type of matching.
  • the other matching section adopts another matching structure, for example, the positive and negative dispersion matching section adopts a uniformly gradual structure, and the negative positive dispersion matching section adopts a stepped jump structure; or, multiple matching sections included in the transmission cable Among them, one part adopts a uniform gradual change structure, and the other part adopts a step jump type structure; or, among the multiple matching sections included in the transmission cable, some matching sections of each matching structure will be adopted; for the above-mentioned various situations, this application does not Make a limit.
  • another embodiment of the present application also discloses a method for manufacturing a transmission cable.
  • the polymer material disclosed in the above embodiment is heat-melted by first making a plastic mold with periodic intervals of thickness and thickness, and then injecting it into Crystallization is carried out in the shaping mold, and after removing the shaping mold, transmission cables with periodic intervals of thickness and thickness can be obtained.
  • the structure of the positive and negative dispersion matching segments in the periodic structure is also determined by the shape of the shaping abrasive tool.
  • the transmission cable disclosed in this application is a cable, which has the shape characteristics of periodic arrangement of thickness and thickness; in special cases, it can also be spliced by separate transmission sections and matching sections. to make.
  • FIG. 5 includes a baseband signal processing chip 501, The radio frequency chip 502, the electromagnetic coupling structure 503, and the transmission cable 504 as disclosed in any of the above embodiments, wherein the baseband signal processing chip 501 is electrically connected to the radio frequency chip 502, and the radio frequency chip 502 is also connected to the electromagnetic coupling structure 503, which is electromagnetically coupled
  • the structure 503 is connected to the transmission cable 504.
  • the transmission cable system can integrate transceiver functions.
  • the radio frequency chip 502 includes a radio frequency transmitter chip 5021 and a radio frequency receiver chip 5022.
  • the baseband processing chip 501 when sending a signal, the baseband processing chip 501 is used to receive service signals. After modulation and other processing, the processed signal is sent to the radio frequency transmitter chip 5021. After up-conversion processing, the signal will be coupled through the electromagnetic coupling structure 503 To the transmission cable 504, it is transmitted through the transmission cable 504; when receiving the signal, the transmission cable 504 couples the received signal to the radio frequency receiving end chip 5022 through the electromagnetic coupling structure 503, and the radio frequency receiving end chip 5022 receives the signal. The signal is down-converted, and the processed signal is sent to the baseband signal processing chip 501, and then the baseband signal processing chip 501 demodulates the signal.
  • the transmission cable system further includes a packaging structure 505 for packaging the baseband signal processing chip 501, the radio frequency chip 502, and the electromagnetic coupling structure 503, which play a role of dust protection and can be adapted to standard interfaces in the network .
  • the transmission cable system can be plugged into the server or switch as shown in Figure 1 to realize interconnection and intercommunication within or between cabinets in the data center network.
  • the radio frequency transmitting chip 5021 and the radio frequency receiving chip 5022 can be integrated together to form a radio frequency transceiver chip, which can be composed of a monolithic microwave integrated circuit (MMIC); the baseband signal processing chip can adopt digital Signal processing (Digital signal processing, DSP) chip, Field Programmable Gate Array (FPGA), Application-specific integrated circuit (ASIC), or analog circuit, etc.; electromagnetic coupling structure, can The electromagnetic coupling is achieved in the form of a mode converter or an on-chip integrated antenna.
  • MMIC monolithic microwave integrated circuit
  • the baseband signal processing chip can adopt digital Signal processing (Digital signal processing, DSP) chip, Field Programmable Gate Array (FPGA), Application-specific integrated circuit (ASIC), or analog circuit, etc.
  • electromagnetic coupling structure can The electromagnetic coupling is achieved in the form of a mode converter or an on-chip integrated antenna.
  • Another embodiment of the present application provides a specific transmission cable whose structure is as shown in FIG. 2.
  • the material of the periodic structure is selected as polytetrafluoroethylene.
  • the relative dielectric constant of the material in the D band is 2.1, and the loss The angle tangent is 0.0002.
  • the cross-sectional diameter of the positive dispersion transmission section D p 1.6 millimeters (mm)
  • the length of the positive dispersion transmission section L p 10 mm
  • the cross-sectional diameter of the negative dispersion transmission section D n 2 mm
  • the matching segment adopts a uniformly graded structure, and the D band refers to the frequency of 110GHz-170GHz range.
  • Simulation software is used to simulate the dispersion characteristics of the transmission cable in this embodiment.
  • the calculation result is shown in Figure 6.
  • the total group delay of the transmission cable within 1 meter (m) is 4.23 picoseconds (ps)
  • the corresponding dispersion coefficient is 0.2115ps/GHz/m.
  • the periodic structure disclosed in this application is not used and only solid-core polymer transmission lines with a cross-sectional diameter of 1.6 mm and a cross-sectional diameter of 2 mm are used, the total group delays within 1 m are 30.64 ps and -31.2 ps, respectively.
  • the corresponding dispersion coefficients are 1.532ps/GHz/m and -1.56ps/GHz/m respectively.
  • the embodiment of the present application also provides another specific transmission cable.
  • the structure is as shown in FIG. 2.
  • the specific materials used in the periodic structure, the size of each transmission section, and the length of the matching section are all the same as those in the previous embodiment.
  • the matching section uses a stepped jump structure
  • this embodiment uses a three-step stepped jump structure
  • the total length of the matching section (L J1 + L J2 + L J3 ) satisfies the constraints in the specific implementation conditions, and is not less than the maximum waveguide wavelength in the working frequency band, that is, not less than At the same time, the positive and negative dispersion matching segment has the same structural parameters as the negative positive dispersion matching segment.
  • Simulation software is used to simulate the dispersion characteristics of the transmission cable in this embodiment.
  • the calculation result is shown in Figure 10.
  • the total group delay of the transmission cable within 1m is 5.78ps, and the corresponding dispersion coefficient It is 0.289ps/GHz/m.
  • the periodic structure disclosed in this application is not used and only solid-core polymer transmission lines with a cross-sectional diameter of 1.6 mm and a cross-sectional diameter of 2 mm are used, the total group delays within 1 m are 30.64 ps and -31.2 ps, respectively.
  • the corresponding dispersion coefficients are 1.532ps/GHz/m and -1.56ps/GHz/m respectively.
  • the S parameters in the working frequency band of the transmission cable meeting the size of this embodiment can also be obtained, that is, the transmission parameter and the reflection parameter.
  • the simulation result is shown in Figure 11. It can be seen from the simulation results that in the 120-160GHz frequency band, the reflection parameter is less than -18.5dB, and the transmission parameter is greater than -1.14dB; through conversion, it can be obtained that the unit length loss of the transmission cable in this embodiment is in the 120-160GHz frequency band.
  • the internal range is between 1.3-4.5dB/m. As shown in Figure 12, it not only reduces the total group delay, but also has a lower loss.
  • the positive dispersion transmission section with a cross-sectional diameter of 1.6 mm and the negative dispersion transmission section with a cross-sectional diameter of 2 mm are selected in the above embodiment, and it can be concluded that the dispersion cancellation effect is better in the 135-155 GHz frequency band; if you choose For cross-sectional diameters of other sizes, it can be concluded that the dispersion cancellation effect in other frequency bands is better.
  • the size given in this application is an example and should not be the only value limitation.
  • the embodiment of the present application also provides another specific transmission cable, the structure of which is shown in Figure 13, including a positive dispersion transmission section 1301, a negative dispersion transmission section 1302 and a dispersion matching section 1303, wherein the positive dispersion transmission section 1301
  • the dispersion coefficient is positive, and the dispersion coefficient of the negative dispersion transmission section 1302 is negative.
  • the cross-sectional diameter of the positive dispersion transmission section 1301 is smaller than that of the negative dispersion transmission section 1302, that is, the positive dispersion transmission section 1301 is larger than the negative dispersion transmission section 1301. 1302 is more detailed.
  • the material of the transmission cable is selected as polytetrafluoroethylene, the relative permittivity of this material in the D band is 2.1, and the loss tangent is 0.0002.
  • the cross-sectional diameter of the positive dispersion transmission section D p 1.6 millimeters (mm)
  • the length of the positive dispersion transmission section L p 30 mm
  • the cross section diameter of the negative dispersion transmission section D n 2 mm
  • the matching segment adopts a uniformly gradual structure, and the D band refers to the frequency range of 110 GHz-170 GHz.
  • Simulation software is used to simulate the dispersion characteristics of the transmission cable in this embodiment.
  • the calculation result is shown in Figure 13.
  • the total group delay of the transmission cable within 1 meter (m) is 6.04ps
  • the corresponding dispersion coefficient is 0.302ps/GHz/m. If the structure disclosed in this application is not used, and when only solid polymer transmission lines with a cross-sectional diameter of 1.6 mm and a cross-sectional diameter of 2 mm are used, the total group delays corresponding to 1 m are 30.64 ps and -31.2 ps, respectively.
  • the corresponding dispersion coefficients are 1.532ps/GHz/m and -1.56ps/GHz/m respectively.
  • the simulation calculation is performed with the length of the transmission cable as 63mm, and the S parameters of the transmission cable in the working frequency band, namely the transmission parameter and the reflection parameter, can be obtained.
  • the simulation results are shown in Fig. 14. It can be seen from the simulation results that in the 120-160GHz frequency band, the reflection parameter is less than -17.9dB, and the transmission parameter is greater than -1.56dB; through conversion, it can be obtained that the unit length loss of the transmission cable in this embodiment is in the 120-160GHz frequency band.
  • the internal range is between 0.85-3.9dB/m, as shown in Figure 15, while reducing the total group delay, the loss is also lower.
  • the present application also provides a variety of transmission cables with different structures.
  • the transmission cable includes at least one transmission structure.
  • the transmission structure includes a positive dispersion transmission section 1601, a negative dispersion transmission section 1602, a positive and negative dispersion matching section 1603, a negative positive
  • the four parts of the dispersion matching section 1603 have many different specific structures. For example, like the periodic structure in Figure 2, the transmission sections are arranged in the order of positive and negative; or as shown in Figure 16, the transmission sections are arranged in the order of positive and positive.
  • the transmission section is arranged in the order of positive, negative, negative, negative, positive, and positive; or as shown in Figure 18, the transmission section in the transmission structure is arranged in the order of positive, negative, Arrange in positive order.
  • the same dispersive transmission structure is connected by two axially symmetric impedance matching structures, and the different dispersive transmission sections can be connected by a positive-negative dispersion matching section or a negative-positive dispersion matching section.
  • the lengths of the positive and negative dispersion matching segments and the negative positive dispersion matching segments can be the same or different. For example, in FIG. 18, the lengths of the two types of matching segments are different.
  • the transmission cable may not have a matching section, and the positive dispersion transmission section and the negative dispersion transmission section are directly connected to achieve the effect of canceling the positive and negative dispersion.
  • the transmission cable disclosed in the present application may include only one transmission structure, or may include multiple transmission structures. If multiple transmission structures are included, the transmission cables can be composed of the same transmission structure repeatedly. For example, the transmission cables are repeatedly arranged as shown in Figures 2, 16-18; the transmission cables can also be composed of different transmission structures, for example , The transmission cable includes at least two different transmission structures shown in Figures 2 and 16-18.
  • the dispersion coefficient of the entire transmission cable is smaller than the absolute value of the dispersion coefficient of the single positive dispersion transmission cable or the negative dispersion transmission cable.
  • the total group delay is equal to the product of the dispersion coefficient and the length
  • the total group delay of the positive dispersion transmission section is equal to the product of the dispersion coefficient C p of the positive dispersion transmission section and the length L p
  • the total group delay of the negative dispersion transmission section is equal to The product of the dispersion coefficient C n and the length L n of the negative dispersion transmission section
  • the total group delay of the dispersion matching section is equal to the product of the dispersion coefficient C m and the length L m of the positive and negative dispersion matching section
  • the matching segment includes a positive and negative dispersion matching segment and a negative positive dispersion matching segment, where the total group delay of the positive and negative dispersion matching segment is equal to the product of the dispersion coefficient C 1 and the length L 1 of the positive and negative dispersion matching segment, the negative positive dispersion matching
  • the total group delay of the segment is equal to the product of the dispersion coefficient C 2 and the length L 2 of the negative-positive dispersion matching segment; then the total group delay of the transmission cable can satisfy the following relationship:
  • the total dispersion of the transmission cable is lower than the positive dispersion transmission section under the same length, and also lower than the negative dispersion transmission section under the same length, which can achieve the effect of canceling positive and negative dispersion.

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Abstract

一种传输线缆（504），可实现设备间的高速互联互通，特别在数据中心等需要海量数据传输的领域具有广阔应用。传输线缆（504）包括正色散传输段（1301）、负色散传输段（1302）、以及色散匹配段（1303），其中，正色散传输段（1301）的横截面直径小于负色散传输段（1302）的横截面直径，在传输线缆（504）中，色散匹配段（1303）用于连接正色散传输段（1301）和负色散传输段（1302）。传输线缆（504）可实现色散抵消，降低群延迟总量的效果。

Description

传输线缆
本申请要求于2019年12月28日提交中国国家知识产权局、申请号为201911385172.4、申请名称为“传输线缆”的中国专利申请的优先权，以及要求于2020年5月25日提交中国国家知识产权局、申请号为202010450190.2、申请名称为“传输线缆”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及一种通信互连领域，尤其涉及一种可应用于太赫兹、毫米波波段的传输线缆技术。
背景技术
随着网络数据中心流量的高速增长，对设备间传输速率的要求越来越高。以数据中心机架顶部(Top of Rack，TOR)架构应用场景为例，在数据中心机柜之间以及机柜内部均需要大量的高速线缆进行互连。目前，有源光缆(Active Optical Cables，AOC)和直连铜缆(Direct Attach Cable，DAC)是两种主要的互连方式。然而，AOC线缆在应用过程中需要将电信号转换成光信号，或将光信号转换成电信号，光缆两端的光收发器需要提供光电转换以及光传输功能，会产生较大的功耗和成本；DAC无需进行电光、光电转换，因此具有较低的功耗和成本，但随着工作频率提升而增加的金属损耗会很大程度上限制铜缆的传输距离和速率，同时铜缆具有较大的重量和弯曲半径，不利于在布线密集的场景下进行应用。
基于低功耗、低成本的互补金属氧化物半导体(Complementary Metal Oxide Semiconductor，CMOS)芯片与低损耗聚合物传输线相结合的太赫兹有源线缆(Terahertz active cable，TAC)技术，利用太赫兹波为载波，以聚合物传输线为传输媒质，是一种区别于AOC和DAC的可在数据中心中进行应用的新型互连方式。但现有的TAC由于其色散特性具有随直径长度变化而改变的特点，同时其在工作频带范围内色散特性较差，带内传输的群延迟总量较大。因此，探索低色散、低群延迟的TAC在满足海量数据增长的数据中心场景具有很大的应用前景。
发明内容
本申请提供一种传输线缆，可以解决现有应用于太赫兹、毫米波波段的线缆存在群延迟总量大的问题。
第一方面，提供了一种传输线缆，包括至少一个周期结构，所述周期结构包括正色散传输段、负色散传输段、正负色散匹配段以及负正色散匹配段；所述正色散传输段的色散系数为正，所述负色散传输段的色散系数为负，所述正色散传输段的横截面直径小于所述负色散传输段的横截面直径；所述正负色散匹配段用于连接所述正色散传输段和所述负色散传输段，所述负色散传输段的另一端连接所述负正色散匹配段，或所述正色散传输段的另一端连接所述负正色散匹配段。
本申请实施例通过周期间隔的正色散传输段和负色散传输段，可以进行色散的相互抵消，从而降低群延迟总量，可以满足数据中心场景中海量数据传输的需求。
在一种可能的实现方式中，所述正色散传输段的横截面直径D p和所述负色散传输段的横截面直径D n满足如下关系：
Figure PCTCN2020140109-appb-000001
其中，ε 1为所述周期结构的相对介电常数，c为真空中的光速，f c为工作频带内的最低工作频率。此时，频率不小于f c的信号可以在本申请公开的传输线缆中传输，且信号在传输线缆中能够实现正负色散的相互作用，从而降低信号在该传输线缆中的色散和群延迟总量。
在一种可能的实现方式中，所述正色散传输段的色散系数C p和所述负色散传输段的色散系数C n大小相同，符号相反。此时，可以选取长度相同的正色散传输段和负色散传输段，使两种传输段的群延迟总量接近于0，且相比于各段长度不同，色散系数大小也不同的情况，信号在传输线缆中的工作带宽更大，加工的一致性也更好。
在一种可能的实现方式中，所述周期结构包括的四段结构中每一段的长度均不小于
Figure PCTCN2020140109-appb-000002
其中，ε 1为所述周期结构的相对介电常数，c为真空中的光速，f c为工作频带内的最低工作频率。周期结构中的四段长度满足上述要求，可以实现较低的反射率，降低信号在传输线缆中的传输损耗。
进一步地，该四段结构中每一段的长度均可以为
Figure PCTCN2020140109-appb-000003
的整数倍，当然也可以任意一段或多段的长度为
Figure PCTCN2020140109-appb-000004
的整数倍。进一步地，正色散传输段的长度与负色散传输段的长度均可以为
Figure PCTCN2020140109-appb-000005
n为正整数，即两个传输段倍数相同；正负色散匹配段的长度与负正色散匹配段的长度也可以均为
Figure PCTCN2020140109-appb-000006
m为正整数，即两个匹配段倍数相同。通常情况下，长度为
Figure PCTCN2020140109-appb-000007
的整数倍，线缆的反射参量会小一些，设计上也更为简单。
在一种可能的实现方式中，所述传输线缆还包括屏蔽层，所述屏蔽层包裹所述周期结构，用于屏蔽外界的电磁干扰。屏蔽层可以选用介质泡沫屏蔽层或金属屏蔽层，介质泡沫屏蔽层材料需选取相对介电常数低于介质内芯、具有较低的损耗角正切的介质材料，比如PTFE泡沫等；金属屏蔽层可以选取具有优良电磁屏蔽效果、高电导率的金属材料，比如铜箔、铝箔、锡箔等。
结合上一种实现方式，在一种可能的实现方式中，所述屏蔽层为介质泡沫屏蔽层，其中，所述介质泡沫屏蔽层的相对介电常数小于所述周期结构的相对介电常数ε 1，可以使得信号的电场更集中在内芯中，降低辐射损耗；或者，所述屏蔽层为金属屏蔽层，其中，所述金属屏蔽层的电导率不小于1×10 7秒/米(s/m)；由于金属的电导率越高，对信号的损耗就越小，因此，满足本实施例的条件，可以降低信号在传输线缆中的损耗。
在一种可能的实现方式中，所述正色散传输段的色散系数C p和长度L p，所述负色散传输段的色散系数C n和长度L n，所述正负色散匹配段的色散系数C 1和长度L 1，所述负正色散匹配段的色散系数C 2和长度L 2，满足如下关系：
C n×L n+C p×L p+C 1×L 1+C 2×L 2＝0。
本实施例中，每段周期结构的群延迟总量为0，是最优的情况，可以保证在周期结构内能够实现正负色散相消，实际情况中可能会存在些许偏差，由工艺或者外界环境、线缆老化等因素导致可能出现的偏差，应该也在本申请的保护范围之内。
在一种可能的实现方式中，所述正色散传输段的色散系数C p和长度L p，所述负色散传输段的色散系数C n和长度L n，所述正负色散匹配段的色散系数C 1和长度L 1，所述负正色散匹 配段的色散系数C 2和长度L 2，满足如下关系：
L p＝L n，C p+C n＝0；L 1＝L 2，C 1+C 2＝0。
在本实施例中，正色散传输段和负色散传输段的长度相同，色散系数大小相同，符号相反；正负色散匹配段和负正色散匹配段也是长度相同，色散系数大小相同，符号相反。此时，信号在传输线缆中的工作带宽较大，且具备较好的加工一致性。
在一种可能的实现方式中，所述正负色散匹配段和所述正色散传输段之间的连接面的直径与所述正色散传输段的横截面直径相同，所述正负色散匹配段和所述负色散传输段之间的连接面的直径与所述负色散传输段的横截面直径相同，其中，所述正负色散匹配段的横截面直径呈均匀渐变或阶梯型跳变。
在一种可能的实现方式中，所述负正色散匹配段和所述负色散传输段之间的连接面的直径与所述负色散传输段的横截面直径相同，所述负正色散匹配段和所述下一个周期结构中的正色散传输段之间的连接面的直径与所述正色散传输段的横截面直径相同，其中，所述负正色散匹配段的横截面直径呈均匀渐变或阶梯型跳变。
在上述两个实施例中，如采用均匀渐变型的匹配结构，则可以实现较好地阻抗匹配，反射更少，可以降低信号的传输损耗；而采用阶梯跳变型的匹配结构，则具备工艺简单的优势。此外，匹配结构还可以采用抛物线渐变、双曲线渐变、切比雪夫曲线渐变等几种形式。
在一种可能的实现方式中，所述周期结构的材料包括聚四氟乙烯、聚丙烯、聚乙烯、高密度聚乙烯(HDPE)、聚苯乙烯中的任意一种。周期结构即为包括两个传输段和两个匹配段的一段传输线缆，可以采用上述材料中的任意一种，上述材料在毫米波、太赫兹波段具有较低的损耗，有利于频率在毫米波、太赫兹波段内的信号的传输。
第二方面，提供了一种传输线缆，包括正色散传输段、负色散传输段、以及色散匹配段；所述正色散传输段的色散系数为正，所述负色散传输段的色散系数为负，所述正色散传输段的横截面直径小于所述负色散传输段的横截面直径，其中，所述色散匹配段用于连接所述正色散传输段和所述负色散传输段。
本申请实施例提供的传输线缆包括正色散传输段和负色散传输段，可以进行色散的相互抵消，从而降低群延迟总量，可以满足数据中心场景中海量数据传输的需求。
在一种可能的实现方式中，所述正色散传输段的横截面直径D p和所述负色散传输段的横截面直径D n满足如下关系：
Figure PCTCN2020140109-appb-000008
其中，ε 1为所述周期结构的相对介电常数，c为真空中的光速，f c为工作频带内的最低工作频率。此时，频率不小于f c的信号可以在本申请公开的传输线缆中传输，且信号在传输线缆中能够实现正负色散的相互作用，从而降低信号在该传输线缆中的色散和群延迟总量。
在一种可能的实现方式中，所述正色散传输段的色散系数C p和所述负色散传输段的色散系数C n大小相同，符号相反。此时，可以选取长度相同的正色散传输段和负色散传输段，使两种传输段的群延迟总量接近于0，且相比于各段长度不同，色散系数大小也不同的情况，信号在传输线缆中的工作带宽更大，加工的一致性也更好。
在一种可能的实现方式中，所述色散匹配段包括正负色散匹配段和负正色散匹配段，其中，所述正负色散匹配段用于连接所述正色散传输段和所述负色散传输段，所述负色散传输 段的另一端连接所述负正色散匹配段，或所述正色散传输段的另一端连接所述负正色散匹配段。
在一种可能的实现方式中，所述传输线缆包括多个周期结构，所述周期结构包括正色散传输段、负色散传输段、正负色散匹配段和负正色散匹配段。通过周期间隔的结构，形成满足长距离传输、且具备色散抵消效果的传输线缆。
在一种可能的实现方式中，所述正色散传输段、所述负色散传输段、以及所述色散匹配段的长度均不小于
Figure PCTCN2020140109-appb-000009
其中，ε 1为所述传输线缆的相对介电常数，c为真空中的光速，f c为工作频带内的最低工作频率。传输段或匹配段满足上述要求，可以实现较低的反射率，降低信号在传输线缆中的传输损耗。
在一种可能的实现方式中，所述正色散传输段、所述负色散传输段、以及所述色散匹配段中每一段的长度均为
Figure PCTCN2020140109-appb-000010
的整数倍。进一步地，正色散传输段的长度与负色散传输段的长度均可以为
Figure PCTCN2020140109-appb-000011
n为正整数，即两个传输段倍数相同；正负色散匹配段的长度与负正色散匹配段的长度也可以均为
Figure PCTCN2020140109-appb-000012
m为正整数，即两个匹配段倍数相同。通常情况下，长度为
Figure PCTCN2020140109-appb-000013
的整数倍，线缆的反射参量会小一些，设计上也更为简单。
在一种可能的实现方式中，所述传输线缆还包括屏蔽层，所述屏蔽层包裹所述正色散传输段、所述负色散传输段和所述色散匹配段，用于屏蔽外界的电磁干扰。屏蔽层可以选用介质泡沫屏蔽层或金属屏蔽层，介质泡沫屏蔽层材料需选取相对介电常数低于介质内芯、具有较低的损耗角正切的介质材料，比如PTFE泡沫等；金属屏蔽层可以选取具有优良电磁屏蔽效果、高电导率的金属材料，比如铜箔、铝箔、锡箔等。
在一种可能的实现方式中，所述屏蔽层为介质泡沫屏蔽层，其中，所述介质泡沫屏蔽层的相对介电常数小于所述传输线缆的相对介电常数ε 1，可以使得信号的电场更集中在内芯中，降低辐射损耗；或者，所述屏蔽层为金属屏蔽层，其中，所述金属屏蔽层的电导率不小于1×10 7秒/米(s/m)；由于金属的电导率越高，对信号的损耗就越小，因此，满足本实施例的条件，可以降低信号在传输线缆中的损耗
在一种可能的实现方式中，所述正色散传输段的色散系数C p和长度L p，所述负色散传输段的色散系数C n和长度L n，所述正负色散匹配段的色散系数C 1和长度L 1，所述负正色散匹配段的色散系数C 2和长度L 2，满足如下关系：
Figure PCTCN2020140109-appb-000014
本实施例中，四段总共的色散量低于相同长度下的正色散传输段，或相同长度下的负色散传输段，能够实现正负色散相消效果。实际情况中存在的些许偏差，例如，由工艺或者外界环境、线缆老化等因素导致可能出现的偏差，也在本申请的保护范围之内。
在一种可能的实现方式中，所述正色散传输段的色散系数C p和长度L p，所述负色散传输段的色散系数C n和长度L n，满足如下关系：
L p＝L n，C p+C n＝0。
在本实施例中，正色散传输段和负色散传输段的长度相同，色散系数大小相同，符号相反。此时，信号在传输线缆中的工作带宽较大，且具备较好的加工一致性。应理解，色散系数的大小有一定误差，也在本申请的保护范围之内。
在一种可能的实现方式中，所述色散匹配段和所述正色散传输段之间的连接面的直径与所述正色散传输段的横截面直径相同，所述色散匹配段和所述负色散传输段之间的连接面的直径与所述负色散传输段的横截面直径相同，其中，所述色散匹配段的横截面直径呈均匀渐变或阶梯型跳变。在本实施例中，如采用均匀渐变型的匹配结构，则可以实现较好地阻抗匹配，反射更少，可以降低信号的传输损耗；而采用阶梯跳变型的匹配结构，则具备工艺简单的优势。此外，匹配结构还可以采用抛物线渐变、双曲线渐变、切比雪夫曲线渐变等几种形式。
在一种可能的实现方式中，所述正色散传输段、负色散传输段和所述色散匹配段的材料包括聚四氟乙烯、聚丙烯、聚乙烯、高密度聚乙烯(HDPE)、聚苯乙烯中的任意一种。上述材料在毫米波、太赫兹波段具有较低的损耗，有利于频率在毫米波、太赫兹波段内的信号的传输。
第三方面，提供了一种传输线缆系统，该传输线缆系统包括射频芯片、基带信号处理芯片、电磁耦合结构以及如第一方面或第二方面中任一种可能的实现方式中的传输线缆；其中，所述基带信号处理芯片与所述射频芯片电连接，所述射频芯片还与所述电磁耦合结构相连，所述电磁耦合结构与所述传输线缆相连。
本实施例中提供的传输线缆系统可以应用于数据中心等需要海量数据传输的场景中，起到互联互通的作用。
在一种可能的实现方式中，所述射频芯片包括射频发端芯片和射频收端芯片，所述电磁耦合结构包括第一电磁耦合结构和第二电磁耦合结构，所述传输线缆包括第一传输线缆和第二传输线缆；所述基带处理芯片用于接收业务信号，将信号进行处理后发送给所述射频发端芯片；所述射频发端芯片对收到的信号进行上变频处理，将处理后的信号通过所述第一电磁耦合结构耦合到所述第一传输线缆，通过所述第一传输线缆进行传输；所述第二传输线缆用于接收信号，将接收到的信号通过第二电磁耦合结构耦合到所述射频收端芯片中，所述射频收端芯片对收到的信号进行下变频处理，并将处理后的信号发送到所述基带信号处理芯片，所述基带信号处理芯片用于将收到的信号进行解调。
在一种可能的实现方式中，所述传输线缆系统还包括封装结构，用于封装所述射频芯片、所述基带信号处理芯片以及所述电磁耦合结构。该封装结构可以起到防尘保护的作用，并可以适配网络中的标准接口，无需改变设备接口，即可实现设备间的互联互通。
本申请实施例提供的传输线缆，包括横截面尺寸不同，分别具有正色散特性和负色散特性的传输段，并通过匹配段分别将两种截面尺寸对应的两个传输段连接起来，从而在工作频带内实现了正负色散的部分或全部抵消，在保证优良传输特性的前提下，大大降低了群延迟总量，以及色散对信号的影响。
附图说明
图1为数据中心内部的互连示意图；
图2为本申请实施例提供的一种传输线缆；
图3为本申请另一实施例提供的一种传输线缆中匹配结构示意图；
图4为本申请另一实施例提供的一种传输线缆中匹配结构示意图；
图5为本申请另一实施例提供的一种传输线缆系统；
图6为对本申请另一实施例提供的传输线缆的群延迟特性仿真结果图；
图7为对本申请另一实施例提供的传输线缆的S参数仿真结果图；
图8为对本申请另一实施例提供的传输线缆的损耗特性仿真结果图；
图9为对本申请另一实施例提供的传输线缆中的匹配结构示意图；
图10为对本申请另一实施例提供的传输线缆的群延迟特性仿真结果图；
图11为对本申请另一实施例提供的传输线缆的S参数仿真结果图；
图12为对本申请另一实施例提供的传输线缆的损耗特性仿真结果图；
图13为本申请另一实施例提供的一种传输线缆；
图14为对本申请另一实施例提供的传输线缆的S参数仿真结果图；
图15为对本申请另一实施例提供的传输线缆的损耗特性仿真结果图；
图16为本申请另一实施例提供的一种传输线缆；
图17为本申请另一实施例提供的一种传输线缆；
图18为本申请另一实施例提供的一种传输线缆。
具体实施方式
在对本申请实施例进行详细地解释说明之前，先对本申请实施例的应用场景予以说明。
随着网络数据中心流量的高速增长，对设备间传输速率的要求越来越高。特别是数据中心网络中，需要大量的高速线缆对数据中心的机柜之间以及机柜内部各个服务器之间进行互连，如图1所示，申请提供了一种传输线缆技术，其中的传输线缆具备低色散、低群延迟的特点，可实现太赫兹、毫米波波段的信号传输，可以满足日益增长的数据中心场景中的数据互连需求。
本申请提供了一种传输线缆，如图2所示，该传输线缆包括至少一个周期结构200，该周期结构200包括正色散传输段201、负色散传输段202、正负色散匹配段203以及负正色散匹配段204，其中，正色散传输段201的色散系数为正，负色散传输段202的色散系数为负，正色散传输段201的横截面直径小于负色散传输段202的横截面直径，也就是说，正色散传输段201比负色散传输段202要细一些。
具体连接方式如图2所示，正色散传输段201的一端连接正负色散匹配段203的一端，正负色散匹配段203的另一端连接负色散传输段202的一端，负色散传输段202的另一端连接下一个周期结构的正色散传输段。其中，正色散传输段201、负色散传输段202、正负色散匹配段203以及负正色散匹配段204均为传输线缆的一段，周期结构200即为包括上述四段的传输线缆；周期结构200用于进行色散抵消，可以降低群延迟总量。
应理解，四个段的排序方式是不变的，只是从哪个段起始可以有所不同，也就是说，周期结构还可以有其他的划分方式，例如，以负色散传输段为起始，周期结构包括依次连接的负色散传输段、负正色散匹配段、正色散传输段和正负色散匹配段；或者以负正色散匹配段为起始，周期结构包括依次连接的负正色散匹配段、正色散传输段、正负色散匹配段和负色散传输段；或者以正负色散匹配段为起始，周期结构包括依次连接的正负色散匹配段、负色散传输段、负正色散匹配段和正色散传输段。以上任一种划分方式均在本申请的保护范围之内。
此外，只要传输线缆包括了至少一个本申请公开的周期结构200，即在本申请的保护范 围之内，并不要求传输线缆只包括周期结构200；例如，传输线缆以正色散传输段起始，包括了100个如图2所示的周期结构200和一个作为结束的正色散传输段；或者传输线缆以负色散传输段开始，包括了负色散传输段、负正色散匹配段以及100个如图2所示的周期结构200；或者传输线缆以负色散传输段开始，包括了负色散传输段、负正色散匹配段、100个如图2所示的周期结构200以及一个作为结束的正色散传输段，上述几种可能的排布方式，均在本申请保护范围之内。
本申请实施例将分别具有正色散特性和负色散特性，横截面尺寸不同的传输线缆间隔周期排列，并通过匹配段分别将两种截面尺寸对应的两个传输段连接起来，从而实现了在工作频带内正负色散部分或全部抵消的有益效果，在保证优良传输特性的前提下，大大降低了群延迟总量，并降低了色散对信号的影响。
在本申请实施例中，周期结构200包括的四段结构中每一段的长度均不小于
Figure PCTCN2020140109-appb-000015
即不小于波导波长，其中，ε 1为周期结构200所用材料的相对介电常数，c为真空中的光速，fc为工作频带内的最低工作频率，即f c为信号的基模能够在传输线缆中传输的最小工作频率，频率低于fc的信号将会无法传输。周期结构中的四段长度满足上述要求，可以实现较低的反射率，降低信号在传输线缆中的传输损耗。
进一步地，该四段结构中每一段的长度均可以为波导波长的整数倍，当然也可以任意一段或多段的长度为波导波长的整数倍。进一步地，正色散传输段的长度与负色散传输段的长度均可以为n倍的波导波长，n为正整数，即两个传输段倍数相同；正负色散匹配段的长度与负正色散匹配段的长度也可以均为m倍的波导波长，m为正整数，即两个匹配段倍数相同。通常情况下，长度为波导波长的整数倍，线缆的反射参量会小一些，设计上也更为简单。
在本申请实施例中，正色散传输段201的横截面直径D p和负色散传输段202的横截面直径D n满足如下关系：
Figure PCTCN2020140109-appb-000016
此时，频率不小于f c的信号可以在本申请公开的传输线缆中传输，且信号在传输线缆中能够实现正负色散的相互作用，从而降低信号在该传输线缆中的色散和群延迟总量。
由于群延迟总量等于色散系数与长度的乘积，所以正色散传输段的群延迟总量等于正色散传输段的色散系数C p和长度L p的乘积，负色散传输段的群延迟总量等于负色散传输段的色散系数C n和长度L n的乘积，正负色散匹配段的群延迟总量等于正负色散匹配段的色散系数C 1和长度L 1的乘积，负正色散匹配段的群延迟总量等于负正色散匹配段的色散系数C 2和长度L 2的乘积；四段的群延迟总量可以满足如下关系：
C n×L n+C p×L p+C 1×L 1+C 2×L 2＝0。
应理解，每段周期结构的群延迟总量为0，是最优的情况，可以保证在周期结构内能够实现正负色散相消，实际情况中可能会存在些许偏差，由工艺或者外界环境、线缆老化等因素导致可能出现的偏差，应该也在本申请的保护范围之内。
可选地，正色散传输段的群延迟总量与负色散传输段的群延迟总量之和为0，正负色散匹配段的群延迟总量与负正色散匹配段的群延迟总量之和为0。应理解，此处群延迟总量为0也应包括由工艺或者外界环境、线缆老化等因素导致可能出现的偏差。进一步地，正色散传 输段的长度L p可以等于负色散传输段的长度L n，正负色散匹配段长度L 1可以等于负正色散匹配段的长度L 2；正色散传输段的色散系数C p与负色散传输段的色散系数C n大小相同，符号相反，正负色散匹配段的色散系数C 1与负正色散匹配段的色散系数C 2大小相同，符号相反。此时，相比于各段长度不同，色散系数大小也不同的情况，信号在传输线缆中的工作带宽更大，加工的一致性也更好。
应理解，本申请实施例中所指的色散系数相同，并不要求完全相同，由于工艺误差、线缆老化等因素造成的色散系数出现些许偏差，也应在本申请实施例的保护范围之内。通常情况下，本申请提供的传输线缆，在横截面直径约为
Figure PCTCN2020140109-appb-000017
时，工作频率在f c附近的信号的色散系数接近于0。
在本申请实施例中，传输线缆可以选用低损耗的聚合物材料作为传输线缆的内芯材料，即周期结构可以采用聚合物材料来制备，例如，聚合物材料可以选取为聚四氟乙烯(Polytetra fluoroethylene，PTFE)、聚丙烯(Polypropylene，PP)、聚乙烯(Polyethylene，PE)、高密度聚乙烯(High-density polyethylene，HDPE)、聚苯乙烯(Polystyrene，PS)等在毫米波、太赫兹频段具有低损耗的介质材料。在本申请方案中，传输线缆可以是实芯的介质传输线，即只包括实芯的聚合物材料；也可以用聚合物作为内芯，并在实芯的聚合物材料外面包裹屏蔽层，即用屏蔽层包裹住周期结构，可以屏蔽外界的电磁干扰，提高信号传输性能；其中，屏蔽层可以选用介质泡沫屏蔽层或金属屏蔽层。介质泡沫屏蔽层材料需选取相对介电常数低于介质内芯、具有较低的损耗角正切的介质材料，比如PTFE泡沫等；金属屏蔽层可以选取具有优良电磁屏蔽效果、高电导率的金属材料，比如铜箔、铝箔、锡箔等。
进一步地，在该屏蔽层为介质泡沫屏蔽层时，介质泡沫屏蔽层的相对介电常数小于该周期结构的相对介电常数ε 1，使得信号的电场更集中在内芯中，降低辐射损耗；在屏蔽层为金属屏蔽层时，金属需为良导体，金属的电导率越高，对信号的损耗就越小，通常情况下，金属屏蔽层的电导率不小于1×10 7秒/米(s/m)。
对于本申请方案中的传输线缆，周期结构中的正色散传输段的横截面直径较小，而负色散传输段的横截面直径较大，正、负色散传输段无法直接连接，需通过匹配段结构连接起来，其中匹配段可以是如图3所示的均匀渐变型结构或如图4所示的阶梯跳变型结构。均匀渐变型结构可以实现较好地阻抗匹配，反射更少，可以降低信号的传输损耗；而阶梯跳变型结构具备工艺简单的优势，本申请对阶梯跳变型结构的阶梯数并不做限定，每截阶梯的长度可以相同，图4是以3级阶梯为例，阶梯越少，工艺越简单；阶梯越多，形状会更接近于均匀渐变。
此外，在实现过程中，匹配段除了可以采用均匀渐变型或阶梯跳变型匹配结构外，还有可能采用抛物线渐变、双曲线渐变、切比雪夫曲线渐变等几种形式实现正负色散横截面之间的匹配连接，本申请不做限定。
具体地，周期结构中的正负色散匹配段和负正色散匹配段均位于正色散传输段和负色散传输段中间，用于连接两个传输段，区别仅在于在信号传输方向上，正负色散匹配段用于承接从正色散传输段到负色散传输段，负正色散匹配段用于承接从负色散传输段到正色散传输段；其中，正负色散匹配段和正色散传输段之间的连接面的直径与正色散传输段的横截面直 径相同，正负色散匹配段和负色散传输段之间的连接面的直径与负色散传输段的横截面直径相同；同理，负正色散匹配段两端的横截面直径也满足上述条件。
应理解，正负色散匹配段和负正色散匹配段的结构可以相同，如图3或4所示，两个匹配段相当于彼此旋转了180度；也可以其中一种匹配段采用一种匹配结构，另一种匹配段采用另一种匹配结构，例如，正负色散匹配段采用均匀渐变型结构，负正色散匹配段采用阶梯跳变型结构；或者，在传输线缆包括的多个匹配段中，一部分采用均匀渐变结构，另一部分采用阶梯跳变型结构；或者，在传输线缆包括的多个匹配段中，每种匹配结构都会有部分匹配段采用；对于上述各种情况，本申请不做限定。
进一步地，本申请另一实施例还公开了一种传输线缆的制作方法，可通过先制作粗细间隔周期性排列的塑形模具，将上述实施例公开的聚合物材料热熔后，注入到塑形模具中进行结晶，去除塑形模具后即可获得粗细间隔周期性排列的传输线缆。结合应用场景的需要，还可以选择包裹介质泡沫屏蔽层或金属屏蔽层，包裹方式可以是绕包或纵包等。此外，在周期结构中的正负色散匹配段的结构也由塑形磨具的形状决定。应理解，在通常情况下，本申请公开的传输线缆是一根线缆，该线缆具备粗细周期性排列的形状特性；特殊情况下，也可以由各自独立的传输段和匹配段拼接而成。
本申请另一实施例公开了一种传输线缆系统，可以应用到图1中数据中心机柜内或机柜间的短距互连场景，具体结构如图5所示，包括基带信号处理芯片501、射频芯片502、电磁耦合结构503以及如上述任一实施例中公开的传输线缆504，其中，基带信号处理芯片501与射频芯片502电连接，射频芯片502还与电磁耦合结构503相连，电磁耦合结构503与传输线缆504相连。其中，传输线缆系统可以集成收发功能，此时，射频芯片502包括射频发端芯片5021和射频收端芯片5022，电磁耦合结构和传输线缆也各存在两个，分别用于发送和接收信号。
具体地，在发送信号时，基带处理芯片501用于接收业务信号，经过调制等处理之后，将处理后的信号发送给射频发端芯片5021，进行上变频处理之后，信号将通过电磁耦合结构503耦合到传输线缆504，通过传输线缆504进行传输；在接收信号时，传输线缆504将接收到的信号通过电磁耦合结构503耦合到射频收端芯片5022中，射频收端芯片5022对收到的信号进行下变频处理，并将处理后的信号发送到基带信号处理芯片501，再通过基带信号处理芯片501将信号解调出来即可。
可选地，该传输线缆系统还包括封装结构505，用于封装基带信号处理芯片501、射频芯片502以及电磁耦合结构503，起到防尘保护的作用，并可以适配网络中的标准接口。传输线缆系统可以插在如图1所示的服务器或者交换机上，实现数据中心网络中机柜内部或机柜之间的互联互通。
在本实施例中，射频发端芯片5021和射频收端芯片5022可以集成在一起，形成射频收发芯片，可以由单片微波集成电路(Monolithic Microwave Integrated Circuit，MMIC)构成；基带信号处理芯片可以采用数字信号处理(Digital signal processing，DSP)芯片、现场可编程逻辑门阵列(Field Programmable Gate Array，FPGA)、专用集成电路(Application-specific integrated circuit，ASIC)、或模拟电路等实现；电磁耦合结构，可以通过模式转换器或者片上集成天线的形式来实现电磁耦合。应理解，以上仅为本申请实施例给出的可能情况，其他可 能的实现形式也在本申请的保护范围之内。
本申请另一实施例提供了一种具体的传输线缆，其结构仍如图2所示，周期结构的材料选取为聚四氟乙烯，该材料在D波段的相对介电常数为2.1，损耗角正切为0.0002。在本实施例中，正色散传输段的横截面直径D p＝1.6毫米(mm)、正色散传输段的长度L p＝10mm、负色散传输段的横截面直径D n＝2mm、负色散传输段的长度L n＝10mm、正负色散匹配段长度为L 1＝3mm、负正色散匹配段长度L 2＝3mm，其中，匹配段采用均匀渐变型结构，D波段指的是110GHz-170GHz频率范围。
通过仿真软件对本实施例中传输线缆的色散特性进行模拟，计算结果如图6所示，在135-155GHz频带内，传输线缆在1米(m)内的群延迟总量为4.23皮秒(ps)，对应的色散系数为0.2115ps/GHz/m。如果不采用本申请公开的周期结构，分别只采用横截面直径1.6mm和横截面直径2mm的实芯聚合物传输线时，对应在1m内的群延迟总量分别为30.64ps和-31.2ps，而所对应的色散系数分别为1.532ps/GHz/m、-1.56ps/GHz/m。通过群延迟仿真结果可以看出，采用本申请方案的传输线缆在工作带宽内的群延迟总量远低于单独采用正色散或负色散的两种实芯聚合传输线，具有明显正负色散相消的效果。
在上述结构尺寸的基础上，选取3个周期结构(总长度为78mm)进行仿真计算，可以得到此传输线缆在工作频段内的S参数，即传输参量和反射参量，仿真结果如图7所示。从仿真结果中可以看出，在120-160GHz频带内，反射参量小于-20分贝(dB)，传输参量大于-1.144dB；通过换算可以得到，本实施例中传输线缆的单位长度损耗在120-160GHz频带内介于2.11-4.41dB/m之间，如图8所示，在具备降低群延迟总量的同时，损耗也较低。
进一步地，本申请实施例还给出另一种具体的传输线缆，结构仍如图2所示，周期结构采用的具体材料及各个传输段的尺寸、匹配段的长度均与上一个实施例相同，区别仅在于匹配段采用的是阶梯跳变型结构，本实施例采用的是3级阶梯型跳变结构，具体结构如图9所示，第1阶梯段横截面直径D J1＝1.7mm，第1阶梯段长度L J1＝1mm；第2阶梯段横截面直径D J2＝1.8mm，第2阶梯段长度L J2＝1mm；第3阶梯段横截面直径D J3＝1.9mm，第3阶梯段长度L J3＝1mm。其中，在阶梯型跳变结构中，匹配段的总长度(L J1+L J2+L J3)满足在具体实施条件中的约束，不小于工作频带内的最大波导波长，即不小于
Figure PCTCN2020140109-appb-000018
同时，正负色散匹配段具有与负正色散匹配段相同的结构参数。
通过仿真软件对本实施例中传输线缆的色散特性进行模拟，计算结果如图10所示，在135-155GHz频带内，传输线缆在1m内的群延迟总量为5.78ps，对应的色散系数为0.289ps/GHz/m。如果不采用本申请公开的周期结构，分别只采用横截面直径1.6mm和横截面直径2mm的实芯聚合物传输线时，对应在1m内的群延迟总量分别为30.64ps和-31.2ps，而所对应的色散系数分别为1.532ps/GHz/m、-1.56ps/GHz/m。通过群延迟仿真结果可以看出，采用本申请方案的传输线缆在工作带宽内的群延迟总量远低于单独采用正色散或负色散的两种实芯聚合传输线，虽然相较于采用均匀渐变的匹配结构，群延迟总量稍有提高，但同样具有比较明显的正负色散相消效果，而且制作工艺较为简单。
在上述结构尺寸的基础上，选取3个周期结构(总长度为78mm)进行仿真计算，还可以得到满足本实施例尺寸的传输线缆在工作频段内的S参数，即传输参量和反射参量，仿真结果如图11所示。从仿真结果中可以看出，在120-160GHz频带内，反射参量小于-18.5dB， 传输参量大于-1.14dB；通过换算可以得到，本实施例中传输线缆的单位长度损耗在120-160GHz频带内介于1.3-4.5dB/m之间，如图12所示，在具备降低群延迟总量的同时，也具备较低的损耗。
应理解，上述实施例中选用了横截面直径为1.6mm的正色散传输段和横截面直径为2mm的负色散传输段，可以得出在135-155GHz频带内，色散抵消效果更好；如果选择其他尺寸的横截面直径，则可以得出其他频带范围内色散抵消效果更好，本申请中给出的尺寸是一个示例，不应该作为唯一的取值限定。
本申请实施例还提供了另一种具体的传输线缆，其结构如图13所示，包括正色散传输段1301，负色散传输段1302和色散匹配段1303，其中，正色散传输段1301的色散系数为正，负色散传输段1302的色散系数为负，正色散传输段1301的横截面直径小于负色散传输段1302的横截面直径，也就是说，正色散传输段1301比负色散传输段1302要细一些。
具体地，传输线缆的材料选取为聚四氟乙烯，该材料在D波段的相对介电常数为2.1，损耗角正切为0.0002。在本实施例中，正色散传输段的横截面直径D p＝1.6毫米(mm)、正色散传输段的长度L p＝30mm、负色散传输段的横截面直径D n＝2mm、负色散传输段的长度L n＝30mm、色散匹配段长度L 1＝3mm，其中，匹配段采用均匀渐变型结构，D波段指的是110GHz-170GHz频率范围。
通过仿真软件对本实施例中传输线缆的色散特性进行模拟，计算结果如图13所示，在135-155GHz频带内，传输线缆在1米(m)内的群延迟总量为6.04ps，对应的色散系数为0.302ps/GHz/m。如果不采用本申请公开的结构，分别只采用横截面直径1.6mm和横截面直径2mm的实芯聚合物传输线时，对应在1m内的群延迟总量分别为30.64ps和-31.2ps，而所对应的色散系数分别为1.532ps/GHz/m、-1.56ps/GHz/m。通过群延迟仿真结果可以看出，采用本申请方案的传输线缆在工作带宽内的群延迟总量远低于单独采用正色散或负色散的两种实芯聚合传输线，具有明显正负色散相消的效果。
在上述结构尺寸的基础上，以传输线缆的长度为63mm进行仿真计算，可以得到此传输线缆在工作频段内的S参数，即传输参量和反射参量，仿真结果如图14所示。从仿真结果中可以看出，在120-160GHz频带内，反射参量小于-17.9dB，传输参量大于-1.56dB；通过换算可以得到，本实施例中传输线缆的单位长度损耗在120-160GHz频带内介于0.85-3.9dB/m之间，如图15所示，在具备降低群延迟总量的同时，损耗也较低。
此外，本申请还提供多种不同结构的传输线缆，该传输线缆包括至少一个传输结构，该传输结构包括正色散传输段1601，负色散传输段1602，正负色散匹配段1603，负正色散匹配段1603四个部分，存在多种不同的具体结构，例如，如图2中的周期结构一样，传输段按照正、负的顺序排列；或如图16所示，传输段按照正、正、负、负的顺序排列；或如图17所示，传输段按照正、负、负、负、正、正的顺序排列；或如图18所示，传输结构中传输段按照正、负、正的顺序排列。进一步地，相同的色散传输结构之间通过两段沿轴向对称的阻抗匹配结构相连，而不同色散传输段之间可通过正负色散匹配段或负正色散匹配段进行连接。正负色散匹配段和负正色散匹配段的长度可以相同，也可以不同，例如，图18中，两种匹配段的长度就是不同的。进一步地，传输线缆也可以不存在匹配段，正色散传输段和负色散传输段直接相连，实现正负色散相消的效果。
应理解，本申请公开的传输线缆可以只包括一个传输结构，也可以包括多个传输结构。如果包括多个传输结构，传输线缆可以为同一个传输结构反复构成，例如，传输线缆反复排列如图2、16-18的传输结构；传输线缆也可以由不同的传输结构构成，例如，传输线缆包括图2、16-18中至少两种不同的传输结构。在这里，为了保证色散匹配，整个传输线缆的色散系数小于单独正色散传输线缆或负色散传输线缆的色散系数的绝对值。由于群延迟总量等于色散系数与长度的乘积，所以正色散传输段的群延迟总量等于正色散传输段的色散系数C p和长度L p的乘积，负色散传输段的群延迟总量等于负色散传输段的色散系数C n和长度L n的乘积，色散匹配段的的群延迟总量等于正负色散匹配段的色散系数C m和长度L m的乘积，则群延迟满足如下关系：
Figure PCTCN2020140109-appb-000019
如果匹配段包括正负色散匹配段和负正色散匹配段，其中，正负色散匹配段的群延迟总量等于正负色散匹配段的色散系数C 1和长度L 1的乘积，负正色散匹配段的群延迟总量等于负正色散匹配段的色散系数C 2和长度L 2的乘积；则传输线缆的群延迟总量可以满足如下关系：
Figure PCTCN2020140109-appb-000020
传输线缆的总色散量低于相同长度下的正色散传输段，也低于相同长度下的负色散传输段，能够实现正负色散相消效果。
另外，正色散传输段和负色散传输段、以及匹配段的长度、横截面直径、材料等要求，以及匹配段的具体结构，在前面的实施例中已经描述过，本实施例在此不再赘述。
尽管结合具体特征及其实施例对本申请进行了描述，但在不脱离本申请的精神和范围的情况下，还可对其进行各种修改和组合。相应地，本说明书和附图仅仅是对所附权利要求所界定的方案进行示例性说明，且视为已覆盖本申请范围内的任意和所有修改、变化、组合或其等同物。
显然，本领域的技术人员可以对本申请进行各种改动和变型而不脱离本发明的精神和范围。这样，倘若本申请实施例的这些修改和变型属于本申请权利要求及其等同技术的范围之内，则本申请也包含这些改动和变型在内。

Claims (16)

  1. 一种传输线缆，其特征在于，包括正色散传输段、负色散传输段、以及色散匹配段；
    所述正色散传输段的色散系数为正，所述负色散传输段的色散系数为负，所述正色散传输段的横截面直径小于所述负色散传输段的横截面直径，其中，所述色散匹配段用于连接所述正色散传输段和所述负色散传输段。
  2. 根据权利要求1所述的传输线缆，其特征在于，所述正色散传输段的横截面直径Dp和所述负色散传输段的横截面直径D n满足如下关系：
    Figure PCTCN2020140109-appb-100001
    其中，ε 1为所述周期结构的相对介电常数，c为真空中的光速，f c为工作频带内的最低工作频率。
  3. 根据权利要求1或2所述的传输线缆，其特征在于，所述正色散传输段的色散系数C p和所述负色散传输段的色散系数C n大小相同，符号相反。
  4. 根据权利要求1-3中任一项所述的传输线缆，其特征在于，所述色散匹配段包括正负色散匹配段和负正色散匹配段，其中，所述正负色散匹配段用于连接所述正色散传输段和所述负色散传输段，所述负色散传输段的另一端连接所述负正色散匹配段，或所述正色散传输段的另一端连接所述负正色散匹配段。
  5. 根据权利要求4中任一项所述的传输线缆，其特征在于，所述传输线缆包括多个周期结构，所述周期结构包括正色散传输段、负色散传输段、正负色散匹配段和负正色散匹配段。
  6. 根据权利要求1-5中任一项所述的传输线缆，其特征在于，所述正色散传输段、所述负色散传输段、以及所述色散匹配段的长度均不小于
    Figure PCTCN2020140109-appb-100002
    其中，ε 1为所述传输线缆的相对介电常数，c为真空中的光速，f c为工作频带内的最低工作频率。
  7. 根据权利要求6所述的传输线缆，其特征在于，所述正色散传输段、所述负色散传输段、以及所述色散匹配段中每一段的长度均为
    Figure PCTCN2020140109-appb-100003
    的整数倍。
  8. 根据权利要求1-7中任一项所述的传输线缆，其特征在于，所述传输线缆还包括屏蔽层，所述屏蔽层包裹所述正色散传输段、所述负色散传输段和所述色散匹配段，用于屏蔽外界的电磁干扰。
  9. 根据权利要求8所述的传输线缆，其特征在于，所述屏蔽层为介质泡沫屏蔽层，其中，所述介质泡沫屏蔽层的相对介电常数小于所述传输线缆的相对介电常数ε1。
  10. 根据权利要求8所述的传输线缆，其特征在于，所述屏蔽层为金属屏蔽层，其中，所述金属屏蔽层的电导率不小于1×107秒/米(s/m)。
  11. 根据权利要求4或5所述的传输线缆，其特征在于，所述正色散传输段的色散系数C p和长度L p，所述负色散传输段的色散系数C n和长度L n，所述正负色散匹配段的色散系数C 1和长度L 1，所述负正色散匹配段的色散系数C 2和长度L 2，满足如下关系：
    Figure PCTCN2020140109-appb-100004
  12. 根据权利要求1-11中任一项所述的传输线缆，其特征在于，所述正色散传输段的色散系数C p和长度L p，所述负色散传输段的色散系数C n和长度L n，满足如下关系：
    L p＝L n，C p+C n＝0。
  13. 根据权利要求1-12中任一项所述的传输线缆，其特征在于，所述色散匹配段和所述正色散传输段之间的连接面的直径与所述正色散传输段的横截面直径相同，所述色散匹配段和所述负色散传输段之间的连接面的直径与所述负色散传输段的横截面直径相同，其中，所述色散匹配段的横截面直径呈均匀渐变或阶梯型跳变。
  14. 根据权利要求1-13中任一项所述的传输线缆，其特征在于，所述正色散传输段、负色散传输段和所述色散匹配段的材料相同，包括聚四氟乙烯、聚丙烯、聚乙烯、高密度聚乙烯(HDPE)、聚苯乙烯中的任意一种。
  15. 一种传输线缆系统，其特征在于，包括射频芯片、基带信号处理芯片、电磁耦合结构以及如权利要求1-14中任一项所述的传输线缆；其中，所述基带信号处理芯片与所述射频芯片电连接，所述射频芯片还与所述电磁耦合结构相连，所述电磁耦合结构与所述传输线缆相连。
  16. 根据权利要求15所述的传输线缆系统，其特征在于，所述传输线缆系统还包括封装结构，用于封装所述射频芯片、所述基带信号处理芯片以及所述电磁耦合结构。
PCT/CN2020/140109 2019-12-28 2020-12-28 传输线缆 WO2021129870A1 (zh)

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