Radio frequency coaxial cable and production method thereof

Abstract

This patent application proposes a radio frequency coaxial cable and a production method thereof, which belongs to the field of communication materials. The radio frequency coaxial cable includes an inner conductor, an insulating structure layer, an outer conductor, a shielding structure layer and a sheath structure layer. Among them, the material of the inner conductor is a copper plate, and the copper plate includes a plurality of copper structure layers without grain boundaries with the same crystal plane index stacked along the thickness direction of the copper plate, and the thickness direction of the copper plate is perpendicular to the axial direction of the inner conductor; the insulating structure layer is sleeved on the outside of the inner conductor; the outer conductor is sleeved on the outside of the insulating structure layer; the shielding structure layer is sleeved on the outside of the outer conductor; and the sheath structure layer is sleeved on the outside of the shielding structure layer. The production method of the radio frequency coaxial cable includes: using the copper wire obtained by forming the copper plate as the inner conductor, and sleeve the inner conductor, the insulating structure layer, the outer conductor, the shielding structure layer and the sheath structure layer in sequence to form a radio frequency coaxial cable. While ensuring that the inner conductor has low loss, the cost of the inner conductor can be effectively reduced.

Description

Technical Field

[0001] This patent application relates to the field of communication materials, and specifically, to a radio frequency coaxial cable and a production method thereof. Background Art

[0002] In RF systems such as communication base station antennas, aerospace and military phased array radars, vector network analysis equipment, and medical ultrasonic diagnostic equipment, RF coaxial cable, as the most critical component of these RF components, directly determines the performance indicators and signal transmission quality of the entire RF system. With the rapid development of technologies such as 5G communications, people are placing higher demands on network coverage and signal transmission in dense and complex environments, necessitating the use of high-frequency coaxial cable. Due to the high frequency of use, loss performance is one of the most critical cable properties, considering the skin effect and proximity effect.

[0003] Considering that the loss performance of a cable is primarily determined by the resistivity of the surface materials of the inner and outer conductors, silver has a lower resistivity than copper and aluminum, resulting in lower cable loss. Currently, high-quality high-frequency coaxial cables typically use silver-plated copper wire as the inner conductor to ensure low cable loss under high-frequency signals. Due to the high price of silver, the cost of silver-plated copper wire is 2 to 4 times that of oxygen-free copper, resulting in higher cable costs. Summary of the Invention

[0004] The purpose of this patent application is to propose a radio frequency coaxial cable and a production method thereof, which can effectively reduce the cost of the inner conductor while ensuring that the inner conductor has lower loss.

[0005] The embodiment of this patent application is achieved as follows:

[0006] In a first aspect, an embodiment of the present patent application proposes a radio frequency coaxial cable, comprising an inner conductor, an insulating structure layer, an outer conductor, a shielding structure layer and a sheath structure layer.

[0007] Among them, the material of the inner conductor is copper plate, which includes multiple copper structural layers without grain boundaries stacked along the thickness direction of the copper plate, the crystal plane index of each copper structural layer without grain boundaries is the same, and the thickness direction of the copper plate is perpendicular to the axial direction of the inner conductor; the insulating structural layer is sleeved on the outside of the inner conductor; the outer conductor is sleeved on the outside of the insulating structural layer; the shielding structural layer is sleeved on the outside of the outer conductor; and the sheath structural layer is sleeved on the outside of the shielding structural layer.

[0008] In the second aspect, the embodiment of the present patent application proposes a method for producing a radio frequency coaxial cable as proposed in the embodiment of the first aspect, including: using copper wire obtained by extrusion or drawing of copper plates as the inner conductor, and sequentially stacking the inner conductor, insulation structure layer, outer conductor, shielding structure layer and sheath structure layer to form a radio frequency coaxial cable.

[0009] The radio frequency coaxial cable and its production method proposed in the embodiments of this patent application have the following beneficial effects:

[0010] The radio frequency coaxial cable of this patent application has an inner conductor made of copper plate, which does not require the use of silver material and can effectively reduce the cost of the inner conductor.

[0011] The copper sheet used for the inner conductor features a copper structural layer with no grain boundaries. Because the copper layer has no grain boundaries and the copper lattice orientation is uniform across all layers, it effectively avoids adverse effects on the material's resistivity and signal transmission loss. It also effectively prevents the impact of impurities accumulated at grain boundaries on the copper material's purity, effectively improving the copper material's purity and further reducing the resistivity and signal transmission loss of the material or inner conductor. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of this patent application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present patent application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0013] Figure 1 A schematic structural diagram of a radio frequency coaxial cable proposed in an embodiment of the present patent application;

[0014] Figure 2 A schematic structural diagram of the first copper plate proposed in the embodiment of this patent application;

[0015] Figure 3 A schematic structural diagram of a copper structure layer without grain boundaries proposed in an embodiment of the present patent application;

[0016] Figure 4 A schematic structural diagram of the second copper plate proposed in the embodiment of this patent application;

[0017] Figure 5 A schematic diagram of a production process for an inner conductor proposed in an embodiment of the present patent application;

[0018] Figure 6 A schematic diagram of a production process for an outer conductor proposed in an embodiment of the present patent application;

[0019] Figure 7A schematic diagram of the production process of the first copper plate proposed in the embodiment of this patent application;

[0020] Figure 8 A schematic diagram of the production process of a copper structure layer without grain boundaries proposed in an embodiment of the present patent application;

[0021] Figure 9 This is a schematic diagram of the production process of the second copper plate proposed in the embodiment of this patent application.

[0022] Icon: 10-RF coaxial cable; 11-inner conductor; 12-insulating structural layer; 13-outer conductor; 14-shielding structural layer; 15-sheath structural layer; 100-copper plate; 110-copper structural layer; 120-electroplated copper structural layer; 200-copper plate with large crystal domains; 300-copper rod; 310-copper wire; 400-copper tube. DETAILED DESCRIPTION

[0023] To make the purpose, technical solutions and advantages of the embodiments of this patent application clearer, the technical solutions in the embodiments of this patent application will be described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0024] In the description of this patent application, unless otherwise specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they can refer to direct connection or indirect connection through an intermediary. For those skilled in the art, the specific meanings of the above terms in this patent application can be understood in specific circumstances.

[0025] It should also be noted that the meaning of "multiple" refers to two or more; the range of "value a ~ value b" includes the two end values ​​"a" and "b"; the "unit of measurement" in "value a ~ value b + unit of measurement" represents the "unit of measurement" of both "value a" and "value b".

[0026] In addition, the meanings of “outside the grain boundary” and “inside the grain boundary” include the “grain boundary”; and the meanings of “outside the grain boundary” and “inside the grain boundary” do not include the “grain boundary”.

[0027] The following is a detailed description of a cable and a production method thereof according to an embodiment of the present patent application.

[0028] First, see Figure 1The embodiment of the present patent application provides a radio frequency coaxial cable 10, comprising an inner conductor 11, an insulating structure layer 12, an outer conductor 13, a shielding structure layer 14, and a jacket structure layer 15. The insulating structure layer 12 is sheathed on the outer surface of the inner conductor 11, the outer conductor 13 is sheathed on the outer surface of the insulating structure layer 12, the shielding structure layer 14 is sheathed on the outer surface of the outer conductor 13, and the jacket structure layer 15 is sheathed on the outer surface of the shielding structure layer 14.

[0029] In the embodiment of the present patent application, the material of the inner conductor 11 is a copper plate 100, such as Figure 2 The copper plate 100 includes a plurality of copper structural layers 110 without grain boundaries stacked along the thickness direction of the copper plate 100. The crystal plane index of each copper structural layer 110 without grain boundaries is the same. The thickness direction of the copper plate 100 is perpendicular to the axial direction of the inner conductor 11. Figure 2 direction a shown.

[0030] It is understood that, in this patent application, the copper structure layer 110 without grain boundaries refers to a copper layer made of copper material without copper grain boundaries, such as Figure 3 The copper material without copper grain boundaries can be obtained by directly purchasing processed copper material with the copper grain boundaries removed; or by stamping and cutting copper material with larger crystal domains to remove the areas outside the copper grain boundaries.

[0031] The inventors' research has found that copper grain boundaries within copper materials have a significant negative impact on the material's resistivity and signal transmission loss. Furthermore, impurities in copper materials often accumulate near copper grain boundaries, significantly affecting the copper's purity. A decrease in copper purity significantly negatively impacts the material's resistivity and signal transmission loss. Existing high-frequency coaxial cables typically use ordinary oxygen-free copper as the conductor, which contains numerous copper grain boundaries and typically has a purity of less than 5N to 6N. Therefore, silver-plated copper is often used as the inner conductor to ensure lower losses.

[0032] In the radio frequency coaxial cable 10 of the present patent application, the inner conductor 11 is made of a copper plate 100 , which does not require a silver plating process and can effectively reduce the cost of the inner conductor 11 .

[0033] In the copper sheet 100 used for the inner conductor 11, the grain-boundary-free copper structural layer 110 comprises a copper structure within the grain boundaries of a single copper grain, and each copper structural layer 110 has the same copper lattice orientation. The absence of copper grain boundaries within the copper structural layer 110 effectively mitigates the adverse effects on the material's resistivity and signal transmission loss. This effectively prevents the impact of impurities accumulated at the grain boundaries on the copper material's purity, thereby effectively alleviating the adverse effects of low copper purity on the material's resistivity and signal transmission loss. Therefore, the copper sheet 100 effectively mitigates the effects of copper grain boundaries and impurities, ensuring low losses for the inner conductor 11 even without silver plating.

[0034] In the embodiments of the present patent application, since the inner conductor 11 can achieve lower loss without silver plating, in some exemplary embodiments, the inner conductor 11 and the insulating structure layer 12 are directly connected.

[0035] It can be understood that in the embodiments of the present patent application, any two of the inner conductor 11, the insulating structure layer 12, the outer conductor 13, the shielding structure layer 14 and the sheath structure layer 15 can be directly connected, or a functional layer can be provided as needed.

[0036] In addition, the materials of the insulating structure layer 12, the outer conductor 13, the shielding structure layer 14 and the sheath structure layer 15 can be selected according to the types known in the art. For example, the material of the insulating structure layer 12 is selected from one of polyethylene, expanded polytetrafluoroethylene and microporous polytetrafluoroethylene (e-PTFE for short). The material of the outer conductor 13 is selected from one of copper tape and silver-plated copper tape, and the outer conductor 13 is obtained by spirally winding or welding a metal tape, for example. The material of the shielding structure layer 14 is selected from one of silver-plated copper wire and tin-plated copper wire, and the shielding structure layer 14 is obtained by interlacing and weaving metal wires, for example. The material of the sheath structure layer 15 is selected from one of thermoplastic polyurethane elastomer rubber (TPU for short) and polytetrafluoroethylene propylene, so as to better play the role of enhancing the mechanical strength, wear resistance, chemical corrosion resistance and high flame retardancy of the cable, and better protect the cable.

[0037] Considering that the outer conductor 13 significantly impacts the performance of the RF coaxial cable 10, and that the outer conductor 13 is typically made primarily of copper and is typically silver-plated, in order to further ensure low loss and reduce the cost of the outer conductor 13, in some exemplary embodiments, the outer conductor 13 is also made of a copper plate 100.

[0038] The inventors have discovered that different crystal plane indices have a certain influence on the physical and chemical properties of copper materials. Copper materials with specific crystal plane indices can better meet the use requirements of the conductor of the RF coaxial cable 10 in terms of resistivity, signal transmission loss attenuation performance and flexibility.

[0039] In some exemplary embodiments, when the crystal plane index of each grain-boundary-free copper structure layer 110 is the same, it is further one of Cu(111), Cu(110), Cu(211) and Cu(100).

[0040] It is understandable that in the embodiment of the present patent application, when using the inner conductor 11 and the outer conductor 13 of the copper plate 100, appropriate sizes are conducive to better balancing the performance and processing performance.

[0041] In some exemplary embodiments, the diameter of the inner conductor 11 is less than 0.5 mm, such as, but not limited to, any one of 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, and 0.45 mm, or a range between any two thereof. The outer diameter of the outer conductor 13 is 11 to 14 mm, such as, but not limited to, any one of 11 mm, 11.5 mm, 12 mm, 12.5 mm, 13 mm, 13.5 mm, and 14 mm, or a range between any two thereof. The inner diameter of the outer conductor 13 is 8 to 13 mm, such as, but not limited to, any one of 8 mm, 10 mm, 11 mm, and 13 mm, or a range between any two thereof.

[0042] Regarding processing performance, when using copper material to produce the inner conductor 11, in order to meet the processing technology requirements and the processing product performance requirements, it is usually necessary to first produce the copper material into a copper rod 300 with a diameter of about 8 mm (such as Figure 5 As shown), the copper rod 300 is then drawn into a copper wire 310 with a specific diameter (as shown). Figure 5 As shown), the copper wire 310 is the copper matrix of the inner conductor 11. When using copper material to produce the outer conductor 13, it is usually necessary to use a plate with a thickness of about 10 mm so that a copper tube 400 with an outer diameter of 10 to 20 mm (such as Figure 6 As shown in FIG. 4 , the copper tube 400 is the copper base of the outer conductor 13 .

[0043] Considering that copper materials without copper grain boundaries are usually thin, they cannot well meet the processing requirements of the inner conductor 11, and even less well meet the processing requirements of the outer conductor 13. Therefore, in the embodiment of the present patent application, multiple copper structural layers 110 without copper grain boundaries are stacked to form the copper plate 100, so that the thickness specifications of the copper plate 100 can better meet the processing requirements of the inner conductor 11.

[0044] Furthermore, in the thickness direction of the copper plate 100, the thickness of the copper plate 100 is 9 to 20 mm, for example, but not limited to, any one of 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm and 20 mm, or a range between any two of them, so as to better meet the processing requirements of the inner conductor 11 and the outer conductor 13.

[0045] Considering that the boundaries of copper grains in copper materials are generally polygonal and close to rectangular, and the cross-section of the plate material used to process the copper rod 300 and the copper tube 400 is generally regular, such as a rectangle, when processing the copper material, copper material without copper grain boundaries is obtained from the rectangular region within the boundaries of the copper grains. This not only meets the shape requirements of the copper plate, but also increases the utilization rate of the copper material and reduces the cost of the copper material without copper grain boundaries.

[0046] Since the plurality of copper structural layers 110 without grain boundaries are stacked along the thickness direction of the copper plate 100 , a section of the copper plate 100 perpendicular to the thickness direction of the copper plate 100 is a copper plate cross section.

[0047] In some possible implementations, the cross-section of the copper plate is rectangular, so that the shape of the copper plate 100 better meets processing requirements and has a lower material cost.

[0048] Considering that in existing processes, when producing copper materials with large crystal domains and processing copper materials without copper grain boundaries, the number of grain boundaries in the large crystal domain copper materials can be effectively controlled to a specification of 1 per square decimeter, in which case the size of the copper crystal domain is approximately 1 square decimeter. Since copper crystal domains are generally polygonal with a long axis and a short axis of comparable length, that is, the shape and size of the copper crystal domain are comparable to a square with an area of ​​1 square decimeter, to facilitate the production of copper materials without copper grain boundaries and ensure a high utilization rate of the large crystal domain copper materials, the shape and size of the copper materials without copper grain boundaries can be selected to be close to a square with an area of ​​1 square decimeter.

[0049] In the embodiment where the cross section of the copper plate is rectangular, the cross section of the copper plate has a first rectangular side and a second rectangular side that are perpendicular to each other.

[0050] As an example, the length of the first rectangular side is 80-100 mm, and the length of the second rectangular side is 80-100 mm. The lengths of the first rectangular side and the second rectangular side can each be any one of 80 mm, 85 mm, 90 mm, 95 mm, and 100 mm, or a range between any two of them, for example, both are the same and are 90 mm.

[0051] Considering the existing process, when producing large-domain copper material to process copper material without copper grain boundaries, in order to meet the size specifications of the copper plate 100, the thickness of the large-domain copper material is usually smaller, so that the thickness of the copper structure layer 110 without grain boundaries is smaller.

[0052] In some possible embodiments, in order to conveniently obtain a copper structural layer 110 without grain boundaries, the thickness of each copper structural layer 110 without grain boundaries is 25 to 100 μm in the thickness direction of the copper plate, for example but not limited to any one of 25 μm, 40 μm, 50 μm, 60 μm, 75 μm and 100 μm, or a range between any two of them.

[0053] It is understandable that in the embodiment of the present patent application, the copper plate 100 may be composed of a plurality of copper structural layers 110 without grain boundaries. The copper plate 100 may also include other functional layers while meeting the performance requirements of the inner conductor 11 and the outer conductor 13 .

[0054] In the first exemplary embodiment, the copper plate 100 is composed of a plurality of copper structural layers 110 without grain boundaries. Since the copper plate 100 only contains the copper structural layers 110 without grain boundaries, the single crystal state and high purity of the copper plate 100 can be effectively guaranteed.

[0055] Considering the high cost of copper material without copper grain boundaries, adding a layer of higher-purity copper material to the copper sheet 100 helps reduce the cost of the copper sheet 100 while meeting the usage requirements of the copper sheet 100. Electroplated copper, when obtained using high-purity electrolytic copper, can approach a single-crystal structure, possessing high purity and a small number of crystals. Adding electroplated copper to the copper sheet 100 has minimal impact on the purity and number of grain boundaries of the copper sheet 100, enabling the copper sheet 100 to meet the performance requirements of the inner and outer conductors 11 and 13.

[0056] See also Figure 4In a second exemplary embodiment, the copper sheet 100 further includes multiple electroplated copper structural layers 120. Each grain-boundary-free copper structural layer 110 has at least one electroplated copper structural layer 120 on both sides thereof in the thickness direction of the copper sheet. In this embodiment, the electroplated copper structural layers 120 on both sides of the grain-boundary-free copper structural layer 110 are used to increase the thickness of the copper sheet 100. When obtaining a copper sheet 100 of a certain thickness, the amount of grain-boundary-free copper structural layer 110 used can be reduced, thereby reducing the cost of the copper sheet 100.

[0057] Considering that the electroplated copper structural layer 120 needs to have an appropriate proportion to effectively ensure the overall purity and grain boundary quantity of the copper plate 100, optionally, in the thickness direction of the copper plate, each electroplated copper structural layer 120 has a thickness of 50-200 μm, for example, but not limited to, any point value of 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 180 μm, and 200 μm, or a range of values ​​therebetween.

[0058] Since annealing treatment can make the electroplated copper structural layer 120 closer to a single crystal structure and can effectively reduce the oxidation of the material surface, optionally, the material of the electroplated copper structural layer 120 is annealed electroplated copper, so that the electroplated copper structural layer 120 has better purity and fewer grain boundaries, which is beneficial to effectively improve the copper plate 100's resistance to signal transmission loss attenuation while reducing costs by using the electroplated copper structural layer 120.

[0059] Considering that the difference in crystal plane index between different copper material layers will affect the overall consistency of the copper plate 100 , further, the crystal plane index of the electroplated copper structure layer 120 is the same as the crystal plane index of the copper structure layer 110 without grain boundaries.

[0060] It will be appreciated that in embodiments further including an electroplated copper structural layer 120, since the electroplated copper structural layer 120 needs to be formed by electroplating on the surface of the grain-boundary-free copper structural layer 110, as an example, an electroplated copper structural layer 120 is formed on both surfaces of each grain-boundary-free copper structural layer 110 to effectively enhance the thickening effect of the electroplated copper structural layer 120. In this embodiment, the copper sheet 100 has two electroplated copper structural layers 120 between any two adjacent grain-boundary-free copper structural layers 110 in the thickness direction of the copper sheet 100. The grain-boundary-free copper structural layers 110 located on both sides of the multiple grain-boundary-free copper structural layers 110 are referred to as the surface-side grain-boundary-free copper structural layers 110, and the surface of the surface-side grain-boundary-free copper structural layer 110 has one electroplated copper structural layer 120.

[0061] Secondly, the embodiments of the present patent application provide a method for producing a radio frequency coaxial cable 10, which can be used to produce the radio frequency coaxial cable 10. The production method includes: using a copper wire 310 obtained by extrusion or drawing a copper plate 100 as an inner conductor 11, and sequentially forming the inner conductor 11, an insulating structure layer 12, an outer conductor 13, a shielding structure layer 14, and a sheath structure layer 15 to form the radio frequency coaxial cable 10.

[0062] When producing the radio frequency coaxial cable 10 in which the outer conductor 13 is also made of the copper plate 100 , the production method further includes: using the copper tube 400 formed from the copper plate 100 as the outer conductor 13 .

[0063] It is understandable that in the embodiment of the present patent application, the copper wire 310 and the copper tube 400 formed by forming the copper plate 100 can be products processed by a supplier, or can be formed by processing the copper plate 100.

[0064] See also Figure 5 In some exemplary embodiments, a method for producing copper wire 310 includes extruding a copper plate 100 to form a copper rod 300. The diameter of copper rod 300 may be 6 to 10 mm, such as, but not limited to, any one of 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, and 10 mm, or any range therebetween. Copper rod 300 is then drawn to form copper wire 310.

[0065] See also Figure 6 In some exemplary embodiments, the method for producing the copper tube 400 includes: extruding the copper plate 100 to obtain the copper tube 400 .

[0066] In addition, it is understandable that in the embodiment of the present patent application, the copper plate 100 can be obtained by direct purchase, or by processing copper materials such as multiple grain-boundary-free copper structural layers 110 .

[0067] See also Figure 7 As an example, the production of the copper plate 100 includes stacking multiple grain-boundary-free copper structural layers 110 along the thickness direction of the copper plate 100, followed by heating and rolling. Directly using the grain-boundary-free copper structural layers 110, the stacked multiple grain-boundary-free copper structural layers 110 can be completed by heating and rolling, which is simple to operate.

[0068] It is understood that in the embodiment of the present patent application, the copper material without copper grain boundaries of the grain-boundary-free copper structural layer 110 can also be purchased directly or produced during the production process of the copper plate 100. Considering that the copper material without copper grain boundaries produced during the production process can be directly used, it is convenient to control the copper material without copper grain boundaries in the same batch to have good consistency, and it can also effectively prevent the copper material without copper grain boundaries from being oxidized.

[0069] For some possible implementations, see Figure 8 When producing the copper plate 100, before stacking multiple grain-boundary-free copper structural layers 110 along the thickness direction of the target material, the process also includes: heating and annealing the oxygen-free copper plate to increase the crystal domain size in the oxygen-free copper plate to obtain a copper plate 200 with large crystal domains; removing the area outside the boundary of the copper grains in the copper plate 200 with large crystal domains, for example, by stamping and cutting to remove the area outside the boundary of the copper grains in the copper plate 200 with large crystal domains to obtain the copper structural layer 110 without grain boundaries.

[0070] For example, the purity of the oxygen-free copper plate is 3N to 4N, for example, 99.95%. Research has found that after heating and annealing, the large-crystal-domain copper plate 200 and the grain-boundary-free copper structure layer 110 can have the following characteristics: in the large-crystal-domain copper plate 200, the number of grain boundaries is less than 1 per square decimeter, and impurities are concentrated in the area 1mm outside the grain boundaries; in the grain-boundary-free copper structure layer 110, the purity is 5N to 7N, for example, 5N to 60N, and the hardness is 30 to 60HV, and the hardness is further 30 to 50HV, for example, 30 to 40HV.

[0071] In existing technologies, crude copper or cathode electrolytic copper is typically used as raw material. This raw material is processed into molten copper through high-temperature smelting and refining processes. This raw material is then subjected to continuous casting and rolling to produce low-oxygen copper material, or oxygen-free copper material is produced by combining up-drawing and dip-coating methods. The final products produced are copper strips, copper rods 300, and copper tubes 400. Research has shown that using these existing methods, the purity of the copper material typically cannot reach 5N or even 6N.

[0072] In addition, in the prior art, in order to improve the purity of copper, it has been proposed to adopt a Czochralski method and a continuous casting directional solidification process based on the regional melting and electrolytic refining purification process, which can achieve the production of high-purity copper materials of 5N to 6N. However, the process is complex and the equipment requirements are high. In addition, when producing a copper rod 300 with a diameter of about 8 mm for drawing the copper wire 310, it is impossible to achieve control of the grain boundary-free condition.

[0073] In this patent application, a copper structural layer 110 without grain boundaries is obtained by heating and annealing an oxygen-free copper plate and then removing the areas outside the boundaries of the copper grains. The production method is simple and requires low equipment. The copper plate 100 composed of the obtained copper structural layer 110 without grain boundaries can effectively control the grain boundary-free condition when producing a copper rod 300 with a diameter of approximately 8 mm for drawing a copper wire 310.

[0074] It can be understood that in the embodiment of the present patent application, the step of stacking multiple copper structural layers 110 without grain boundaries along the thickness direction of the copper plate is not limited to stacking only the copper structural layers 110 without grain boundaries, and other functional layers can also be stacked between the copper structural layers 110 without grain boundaries and / or on the outer surfaces of multiple copper structural layers 110 without grain boundaries.

[0075] In the embodiment where the copper sheet 100 further comprises an electroplated copper structural layer 120, see Figure 9 The step of stacking multiple copper structural layers 110 without grain boundaries along the thickness direction of the copper plate includes: first forming an electroplated copper structural layer 120 on at least one surface of at least a portion of the copper structural layer 110 without grain boundaries, and then stacking the multiple copper structural layers 110 without grain boundaries so that in the thickness direction of the copper plate, both sides of each copper structural layer 110 without grain boundaries have at least one electroplated copper structural layer 120.

[0076] As an example, the step of stacking multiple grain-boundary-free copper structural layers 110 along the thickness direction of the copper plate includes: first forming an electroplated copper structural layer 120 on both surfaces of each grain-boundary-free copper structural layer 110, and then stacking the multiple grain-boundary-free copper structural layers 110. In this embodiment, the copper plate 100 obtained has two electroplated copper structural layers 120 between any two adjacent grain-boundary-free copper structural layers 110, and one electroplated copper structural layer 120 is located on the surface of the surface-side grain-boundary-free copper structural layer 110.

[0077] In order to ensure that the electroplated copper structure layer 120 has a higher purity, optionally, when forming the electroplated copper structure layer 120 on the surface of the copper structure layer 110 without grain boundaries, high-purity electrolytic copper is used for electroplating.

[0078] Taking into account that the annealing treatment can make the electroplated copper structural layer 120 closer to a single crystal structure and can effectively reduce the oxidation of the material surface, in the implementation scheme in which the electroplated copper structural layer 120 is formed, after heating and rolling, it also includes: performing annealing treatment to increase the crystal domain size in the electroplated copper structural layer 120, so that the material of the electroplated copper structural layer 120 is annealed electroplated copper.

[0079] Optionally, the cooling rate and atmosphere of the annealing are controlled so that after the annealing process, the crystal plane index of the electroplated copper structure layer 120 is the same as the crystal plane index of the copper structure layer 110 without grain boundaries.

[0080] The features and performance of this patent application are further described in detail below in conjunction with the embodiments.

[0081] The embodiment of the present patent application proposes a method for producing a radio frequency coaxial cable, which includes:

[0082] S1. Production of copper sheets.

[0083] S2. Extrude the copper sheet into a copper rod, and then draw the copper rod into a copper wire to obtain the inner conductor.

[0084] S3. Provide an insulating structural layer outside the inner conductor.

[0085] S4. Arrange an outer conductor outside the insulating structure layer. The outer conductor is made of a copper plate, which is extruded into a copper rod to obtain the outer conductor.

[0086] S5. Set up a shielding structure layer outside the insulation structure layer.

[0087] S6. Provide a sheath structure layer outside the shielding structure layer.

[0088] The copper sheet used in each embodiment of this patent application is produced by the following method:

[0089] Method 1:

[0090] A method for producing a copper plate, comprising:

[0091] S11. The original multi-grain boundary oxygen-free copper plate (grade C10200, grain boundary number > 10000 / cm 2 ) is placed in an annealing device and an inert gas such as nitrogen, argon or helium is introduced to increase the temperature.

[0092] S12. When the annealing equipment reaches 800-1075°C, reducing gases such as H2 and CO are introduced to start the annealing process.

[0093] S13. After the annealing is completed, an inert gas is continuously introduced into the annealing equipment to cool the copper strip to room temperature, thereby obtaining a large-crystal copper plate with a low number of grain boundaries and large-sized crystal domains.

[0094] S14. Take samples of copper plates with large crystal domains and perform X-ray (XRD) analysis and test, and detect the number of grain boundaries N, and select the peak intensity of single crystal domains with specific crystal plane index > 3*10 3 Qualified large crystal domain copper plate with the number of grain boundaries NN≤1 / square decimeter.

[0095] S15. After cooling, the qualified large-crystal domain copper plate is punched and cut by a die to remove the area outside the boundary of the copper grains, thereby obtaining a copper structure layer with no grain boundaries in the positive direction and a size of 90*90 mm.

[0096] S16. Electroplating is performed on both sides of each copper structural layer without grain boundaries to form an electroplated copper structural layer, and then the copper structural layer without grain boundaries formed with the electroplated copper structural layer is stacked along the thickness direction of the copper plate, and then heated and rolled, and then annealed, and products with the same crystal plane index of the electroplated copper structural layer and the crystal plane index of the copper structural layer without grain boundaries are screened to obtain a copper plate.

[0097] Method 2:

[0098] A method for producing a copper plate, which differs from method 1 only in step 1S6.

[0099] In this method, step S16 includes: stacking a plurality of copper structure layers without grain boundaries along the thickness direction of the copper plate, and then heating and rolling to obtain the copper plate.

[0100] Test example

[0101] A plurality of copper plates are produced using the copper plate production method in the RF coaxial cable production method of the embodiment, and are numbered as embodiment n (n is an integer ≥ 1); compared with the comparative embodiment, the only difference is that the polygrain boundary oxygen-free copper plate used in the embodiment is directly used instead of the grain-free copper structural layer.

[0102] The performance parameters of the copper plates produced in the embodiments and comparative examples were examined.

[0103] The testing standards are as follows:

[0104] (1) Grain boundary number detection: Observe under a metallographic microscope and randomly select the number of grain boundaries within the range of 100*100mm.

[0105] (2) Hardness: GB-T-4340.1.

[0106] (3) Electrical conductivity: GB-T-351.

[0107] (4) Copper purity and oxygen content testing: GB / T 5121.

[0108] In this patent application, the experimental conditions of the copper plates in the embodiments and comparative examples are shown in Table 1, and the test results are also shown in Table 1. Among them, the copper structure layer without grain boundaries in the embodiments and the oxygen-free copper plate in the comparative examples are represented by the basic copper layer.

[0109] Table 1. Process and material parameters of copper plates

[0110]

[0111]

[0112]

[0113] As can be seen from Table 1, the copper plate proposed in the embodiment of this patent application, in which the copper structural layer without grain boundaries has better conductivity and higher purity than the oxygen-free copper plate with multiple grain boundaries, is more able to meet the requirements of the resistivity and signal transmission loss attenuation performance of the conductor of the RF coaxial cable.

[0114] According to the comparison between comparative examples 1 to 4 and embodiment 1, the conductivity and purity of the copper plate are significantly improved when the grain boundary-free copper layer is used compared with the multi-grain boundary copper.

[0115] According to the comparison between comparative examples 5 and 6 and embodiment 1, when the number of grain boundaries of the copper material is reduced in the comparative example, even if the number of grain boundaries is 4 to 5 / dm 2 According to the standards, copper grain boundaries will also have a significant impact on the conductivity and purity properties of copper plates.

[0116] According to the comparison between Example 2 and Example 1, in the copper plate provided with electroplated copper, when the thickness of the electroplated copper is smaller, the copper plate can exhibit better conductivity and purity performance.

[0117] According to the comparison between Example 3 and Example 1, when the copper plate is composed only of the grain-boundary-free copper layer, the electrical conductivity and purity of the copper plate are further improved compared with the copper plate provided with electroplated copper.

[0118] The embodiments described above are part of the embodiments of this patent application, rather than all of the embodiments. The detailed description of the embodiments of this patent application is not intended to limit the scope of the patent application claimed for protection, but merely represents selected embodiments of this patent application. Based on the embodiments in this patent application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this patent application.

Claims

1. A radio frequency coaxial cable, characterized in that: include: An inner conductor is made of a copper plate, the copper plate comprising a plurality of copper structural layers without grain boundaries stacked along the thickness direction of the copper plate, the crystal plane index of each copper structural layer without grain boundaries being the same, and the thickness direction of the copper plate being perpendicular to the axial direction of the inner conductor; the copper plate further comprising a plurality of electroplated copper structural layers; in the thickness direction of the copper plate, each of the copper structural layers without grain boundaries has at least one electroplated copper structural layer on both sides thereof, the material of the electroplated copper structural layer being annealed electroplated copper; the crystal plane index of each copper structural layer without grain boundaries being one of Cu(111), Cu(110), Cu(211) and Cu(100); An insulating structural layer, sleeved outside the inner conductor; An outer conductor is sleeved outside the insulating structure layer; A shielding structure layer, sleeved outside the outer conductor; as well as The sheath structure layer is sleeved outside the shielding structure layer.

2. The radio frequency coaxial cable according to claim 1, wherein: The crystal plane index of the electroplated copper structure layer is the same as the crystal plane index of the copper structure layer without grain boundaries.

3. The radio frequency coaxial cable according to claim 2, characterized in that: In the thickness direction of the copper plate, there are two electroplated copper structural layers between any two adjacent copper structural layers without grain boundaries, and the copper structural layers without grain boundaries located on both sides of the multiple copper structural layers without grain boundaries are surface copper structural layers without grain boundaries, and the surface of the surface copper structural layer without grain boundaries has one electroplated copper structural layer.

4. The radio frequency coaxial cable according to any one of claims 1 to 3, characterized in that: The outer conductor is made of the copper plate.

5. A method for producing a radio frequency coaxial cable according to claim 1, characterized in that: include: The copper wire obtained by extrusion or drawing the copper sheet is used as the inner conductor, and the inner conductor, the insulating structure layer, the outer conductor, the shielding structure layer and the sheath structure layer are sequentially sheathed to form the radio frequency coaxial cable; The production method further comprises: First, an electroplated copper structural layer is formed on at least one surface of at least a portion of the copper structural layer without grain boundaries, and then the multiple copper structural layers without grain boundaries are stacked so that in the thickness direction of the copper plate, both sides of each of the copper structural layers without grain boundaries have at least one electroplated copper structural layer; then, heating and rolling are performed, and annealing treatment is performed to increase the crystal domain size in the electroplated copper structural layer to obtain the copper plate.

6. The production method according to claim 5, characterized in that The production method further comprises: using the copper tube formed from the copper sheet as the outer conductor.

7. The production method according to claim 5, characterized in that After the annealing treatment, the crystal plane index of the electroplated copper structure layer is the same as the crystal plane index of the copper structure layer without grain boundaries.

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