Ultra-high temperature resistant radio frequency coaxial cable and manufacturing method thereof

Abstract

The present invention relates to an ultra-high temperature resistant radio frequency coaxial cable and a method for manufacturing the same. The present invention comprises an inner conductor, an insulating foam layer, a first outer conductor, a glass fiber tape, a silica aerogel coating, a second outer conductor, a flame retardant and fire-resistant layer, and a flame retardant sheath layer, which are sequentially arranged from the inside to the outside: the first outer conductor has a first corrugated structure including crests and troughs; the second outer conductor has a second corrugated structure including crests and troughs; the positions of the crests and troughs of the first corrugated structure are consistent with the positions of the crests and troughs corresponding to the second corrugated structure, and air layers are formed between the first corrugated structure and the glass fiber tape, and between the second corrugated structure and the silica aerogel coating. The present invention significantly improves the safety and reliability of cables in extreme environments such as fires, and avoids communication interruption of radio frequency coaxial cables in high-temperature environments such as fires.

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency coaxial cables, and in particular to an ultra-high temperature resistant radio frequency coaxial cable and a manufacturing method thereof. Background Art

[0002] RF cables are primarily used for signal connections between devices and antennas. Existing RF coaxial cables typically consist of an inner conductor, an insulation layer, an outer conductor, and a sheath. The insulation layer between the inner and outer conductors serves as the primary carrier for signal transmission. The insulation layer is typically made of high-density polyethylene (HDPE) and low-density polyethylene (LDPE) foam, supplemented with a nucleating agent. After mixing in a specific ratio, an inert gas such as carbon dioxide or nitrogen is injected to create the foam. The melting temperature of the polyethylene material is typically between 100°C and 140°C.

[0003] In abnormal situations such as fire, if the cable is exposed to a high-temperature combustion environment for a long time, the polyethylene insulation layer in the existing coaxial cable will easily melt and collapse due to the high temperature, resulting in the inability to transmit signals normally, thus causing communication interruption accidents. Summary of the Invention

[0004] To this end, the present invention provides an ultra-high temperature resistant radio frequency coaxial cable and a manufacturing method thereof. In order to address the problem that the insulation layer of the existing coaxial cable is easily melted and collapsed during combustion, thereby causing signal interruption, the structure and process of the radio frequency coaxial cable are improved, thereby significantly improving the safety and reliability of the cable in extreme environments such as fire, and avoiding communication interruption of the radio frequency coaxial cable in high temperature environments such as fire.

[0005] To solve the above technical problems, the present invention provides a method for manufacturing an ultra-high temperature resistant radio frequency coaxial cable, comprising:

[0006] providing an inner conductor;

[0007] Preparation of the insulating foam layer: a high-density foaming material, a low-density foaming material and a nucleating agent are mixed in a set mass ratio, and carbon dioxide gas is injected at the same time. A special extrusion die is used in conjunction with an extruder head to push and form a uniformly distributed foam structure on the outer surface of the inner conductor. After cooling and shaping in a hot water tank and a cold water tank in sequence, an insulating foam layer covering the outer surface of the inner conductor is obtained;

[0008] Forming the first outer conductor: performing a first corrugation welding process on the outer surface of the insulating foam layer, including sequentially subjecting the copper strip to cleaning, cutting, preforming, copper tube forming, copper tube welding, and eccentric rolling to form a first outer conductor coated on the outer surface of the insulating foam layer, the first outer conductor having a first corrugated structure including crests and troughs;

[0009] Glass fiber tape wrapping: using concentric wrapping equipment to wrap the glass fiber tape around the surface of the first outer conductor to form a first semi-finished product structure;

[0010] Silica aerogel spraying: spraying a silica aerogel coating evenly on the surface of the glass fiber tape;

[0011] Forming the second outer conductor: performing a second corrugation welding process on the outer surface of the silica aerogel coating to form a second outer conductor, wherein the second outer conductor has a second corrugated structure including crests and troughs; wherein, during the second corrugation welding process, the positions of the crests and troughs of the first corrugated structure are maintained consistent with the positions of the corresponding crests and troughs of the second corrugated structure, and air layers are formed between the first corrugated structure and the glass fiber tape, and between the second corrugated structure and the silica aerogel coating; simultaneously, during the second corrugation welding process, the silica aerogel coating coated on the surface of the glass fiber tape is dried using the heat generated during the argon arc welding of the copper tube;

[0012] Flame retardant and fire resistant layer wrapping: concentric wrapping is adopted to wrap the fireproof cloth and mica tape around the surface of the second outer conductor in sequence to form a second semi-finished product structure;

[0013] Sheath extrusion: The low-smoke halogen-free flame-retardant sheath material is pushed through an extruder head and a special extrusion die and coated on the surface of the second semi-finished product structure to form a flame-retardant sheath layer, and finally a finished RF coaxial cable is obtained.

[0014] In one embodiment of the present invention, the inner conductor is made of copper-clad aluminum.

[0015] In one embodiment of the present invention, the high-density foaming material, the low-density foaming material and the nucleating agent are mixed in a mass ratio of 71:25:4, and the outer diameter of the insulating foam layer is 12.6 mm±0.20 mm.

[0016] In one embodiment of the present invention, the diameter of the first outer conductor is 13.9 mm ± 0.30 mm, and the trough diameter is 12.1 mm ± 0.50 mm; the diameter of the second outer conductor is 17.2 mm ± 0.30 mm.

[0017] In one embodiment of the present invention, the overlapping rate of the glass fiber tape is 30% to 50%, and the outer diameter of the first semi-finished product structure is 14.8 mm ± 0.20 mm.

[0018] In one embodiment of the present invention, the spraying thickness of the silica aerogel coating is 0.3 mm to 1.0 mm.

[0019] In one embodiment of the present invention, the fireproof cloth is NOMEX fireproof cloth with a thickness of 1 mm to 1.5 mm, and the mica tape has a thickness of 0.14 mm ± 0.01 mm and a width of 45 mm ± 1 mm.

[0020] In one embodiment of the present invention, the overlapping rates of the fireproof cloth and the mica tape are both 30% to 50%, and the outer diameter of the second semi-finished product structure is 27.3 mm ± 0.30 mm.

[0021] In one embodiment of the present invention, the density of the low-smoke halogen-free flame-retardant sheath material is 1.50±0.1g / cm³, the extrusion temperature is 125°C~165°C; and the outer diameter of the flame-retardant sheath layer is 32mm±0.30mm.

[0022] The present invention also provides an ultra-high temperature resistant radio frequency coaxial cable, which is manufactured using the manufacturing method of the ultra-high temperature resistant radio frequency coaxial cable, comprising:

[0023] inner conductor;

[0024] an insulating foam layer, covering the surface of the inner conductor;

[0025] a first outer conductor, coated on the surface of the insulating foam layer, and having a first corrugated structure including crests and troughs;

[0026] A glass fiber tape wrapped around the surface of the first outer conductor;

[0027] A silica aerogel coating is applied to the surface of the glass fiber tape layer;

[0028] A second outer conductor, coated on the surface of the silica aerogel coating, has a second corrugated structure including crests and valleys;

[0029] a flame retardant and fire resistant layer comprising a fireproof cloth and a mica tape sequentially wrapped around the surface of the second outer conductor;

[0030] a flame retardant sheath layer, covering the surface of the flame retardant and fire resistant layer;

[0031] The positions of the crests and troughs of the first corrugated structure are consistent with the positions of the corresponding crests and troughs of the second corrugated structure, and air layers are formed between the first corrugated structure and the glass fiber tape, and between the second corrugated structure and the silica aerogel coating.

[0032] The above technical solution of the present invention has the following advantages over the prior art:

[0033] The ultra-high temperature resistant RF coaxial cable and its manufacturing method described in the present invention significantly improve the safety and reliability of the cable in extreme environments such as fire through structural improvements, and effectively solve the problem of communication interruption of RF coaxial cables in high temperature environments such as fires.

[0034] The present invention implements a second corrugation welding process on the outside of the glass fiber tape and the aerogel layer, so that the radio frequency coaxial cable has a structure with a double-layer corrugated copper tube, which not only enhances the mechanical strength of the cable, but also further improves the thermal insulation effect. During the two corrugation welding processes, the first outer conductor and the second outer conductor are ensured to be precisely aligned with each other's peaks to peaks and troughs to troughs, so that a uniform and stable air layer is formed between the two layers of corrugated copper tubes. By adding an air layer between the inner and outer layers of corrugated conductors, the excellent thermal insulation properties of air are utilized to significantly improve the thermal insulation effect between the two layers, prevent the melting of the insulating foam layer, and ensure the signal transmission effect. Moreover, through the coordinated cooperation of the glass fiber tape, the silica aerogel layer and the air layer, the flame retardant and thermal insulation properties of the middle part of the cable are greatly improved, and the material efficiency is synergistically superimposed to achieve a thermal insulation and flame retardant effect far exceeding that of the superposition of a single material.

[0035] The present invention significantly improves the flame retardancy and heat insulation capabilities of the cable by coating the surface of the first outer conductor with a glass fiber tape and spraying a silica aerogel coating on the surface of the glass fiber tape using a special spraying device, effectively blocking the conduction of external heat to the inner layer and enhancing the overall fire resistance safety.

[0036] During the second corrugation welding process, the heat generated by argon arc welding is used to simultaneously dry the silica aerogel coating on the surface of the glass fiber tape, effectively ensuring the coating effect and adhesion firmness of the aerogel coating and further improving the reliability of the product.

[0037] The present invention coats the surface of the second outer conductor with NOMEX fireproof cloth, which effectively improves the flame retardant and heat-insulating performance of the outer layer of the cable, can continuously block the external heat from being transferred inward, and further ensure the safe operation of the cable in extremely high temperature environments.

[0038] The radio frequency coaxial cable manufactured according to the process of the present invention has been proven through tests to be able to maintain normal communication after withstanding 4 hours of burning in a high-temperature combustion environment of 750°C, significantly improving the safety and reliability of the cable in extreme environments such as fire. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0040] Figure 1 It is a structural transverse cross-sectional view of the ultra-high temperature resistant radio frequency coaxial cable of the present invention.

[0041] Figure 2 It is a longitudinal cross-sectional view of the structure of the ultra-high temperature resistant radio frequency coaxial cable of the present invention.

[0042] Figure 3 It is a partial schematic diagram of the ultra-high temperature resistant radio frequency coaxial cable of the present invention.

[0043] Figure 4 The present invention is a flow chart of a method for manufacturing an ultra-high temperature resistant radio frequency coaxial cable.

[0044] Figure 5 It is a schematic diagram of the attenuation of the ultra-high temperature resistant radio frequency coaxial cable of the present invention before combustion.

[0045] Figure 6 It is a schematic diagram of the attenuation of the ultra-high temperature resistant radio frequency coaxial cable of the present invention after combustion.

[0046] Figure 7 It is a schematic diagram of standing waves of the ultra-high temperature resistant radio frequency coaxial cable of the present invention before combustion.

[0047] Figure 8 It is a schematic diagram of standing waves after the ultra-high temperature resistant radio frequency coaxial cable of the present invention is burned.

[0048] Figure 9 This is a schematic diagram of the impedance of the ultra-high temperature resistant radio frequency coaxial cable of the present invention before combustion.

[0049] Figure 10 It is a schematic diagram of the impedance of the ultra-high temperature resistant radio frequency coaxial cable after combustion of the present invention.

[0050] Description of the accompanying drawings:

[0051] 100, inner conductor;

[0052] 200, insulating foam layer;

[0053] 300, first outer conductor; 310, first corrugated structure; 320, air layer;

[0054] 400, fiberglass tape;

[0055] 500, silica aerogel coating;

[0056] 600, second outer conductor; 610, second corrugated structure; 610a, wave crest; 610b, wave trough;

[0057] 700, fireproof cloth;

[0058] 800, mica tape;

[0059] 900, flame retardant sheath layer. DETAILED DESCRIPTION

[0060] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0061] In the present invention, if directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention.

[0062] In the present invention, "several" means one or more, "multiple" means more than two, "greater than," "less than," "exceeds," etc. are understood to exclude the number itself; "above," "below," "within," etc. are understood to include the number itself. In the description of the present invention, the use of "first" or "second" is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0063] In the present invention, unless otherwise expressly defined, terms such as "disposed," "installed," and "connected" should be interpreted broadly. For example, they may refer to direct connection or indirect connection through an intermediate medium; fixed connection or detachable connection or integral molding; mechanical connection or electrical connection or mutual communication; and internal connection between two components or interaction between two components. Those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0064] Reference Figures 1 to 4 As shown, this embodiment provides a method for manufacturing an ultra-high temperature resistant radio frequency coaxial cable, comprising the following steps:

[0065] S1. Provide an inner conductor 100; the inner conductor 100 is made of copper-clad aluminum.

[0066] S2. Prepare the insulating foam layer 200: Mix a high-density foaming material, a low-density foaming material, and a nucleating agent in a mass ratio of 71:25:4, and inject high-purity carbon dioxide gas at the same time. Use a dedicated extrusion die in conjunction with an extruder head to push and form a uniformly distributed bubble structure on the outer surface of the inner conductor 100. After cooling and shaping in a hot water tank and a cold water tank, the insulating foam layer 200 covering the outer surface of the inner conductor 100 is obtained; the outer diameter of the insulating foam layer 200 is 12.6 mm ± 0.20 mm.

[0067] S3, forming the first outer conductor 300: performing a first corrugation welding process on the outer surface of the insulating foam layer 200, including sequentially subjecting the copper strip to cleaning, cutting, preforming, copper tube forming, copper tube welding and eccentric rolling processes, to form a first outer conductor 300 coated on the outer surface of the insulating foam layer 200, the first outer conductor 300 having a first corrugated structure 310 including a crest 610a and a trough 610b; in this embodiment, the diameter of the first outer conductor 300 is 13.9mm±0.30mm, and the diameter of the trough 610b is 12.1mm±0.50mm. Figure 3 shown.

[0068] It should be noted that when performing corrugation welding, it is first necessary to prepare a copper strip that meets the width and thickness requirements, and to degrease and clean the surface of the copper strip to ensure that the surface of the copper strip is free of oil, oxides, dust and other impurities, so as to improve the reliability and electrical performance of subsequent welding. The copper strip is precisely cut according to the designed width to ensure the dimensional consistency of each process in the subsequent forming process. The copper strip is initially bent or curled to give it an initial circular or elliptical curvature, which is conducive to more accurate subsequent forming into a tubular structure. The preformed copper strip is further bent and fitted using special molds or forming equipment, and finally enclosed into a nearly closed circular tubular structure. The edges of the copper strip are welded using argon arc welding to form a closed metal tube body to achieve mechanical strength and electrical continuity. After the tube body is welded and formed, it is corrugated by an eccentric roller device to form a periodic wave crest 610a and wave trough 610b structure on the tube wall. The eccentric rolling can ensure the precise position of the wave crest 610a and wave trough 610b on the cross section, and the corrugation can improve the overall mechanical strength of the conductor.

[0069] S4. Wrapping the glass fiber tape 400: Using concentric wrapping equipment, wrap the glass fiber tape 400 around the surface of the first outer conductor 300, with an overlap rate of the glass fiber tape 400 of 30% to 50%, to form a first semi-finished product structure; the outer diameter of the first semi-finished product structure is 14.8 mm ± 0.20 mm.

[0070] S5. Silica Aerogel Spraying: Evenly spray a silica aerogel coating 500 onto the surface of the fiberglass tape 400 to a thickness of 0.3mm to 1.0mm. This coating significantly enhances the cable's flame retardancy and thermal insulation capabilities, effectively blocking the transfer of external heat to the inner layer and enhancing overall fire safety.

[0071] S6. Forming the second outer conductor 600: A second corrugation welding process is performed on the outer surface of the silica aerogel coating 500 to form a second outer conductor 600. The second outer conductor 600 has a second corrugated structure 610 including a crest 610a and a trough 610b. The diameter of the second outer conductor 600 is 17.2 mm ± 0.30 mm. During the second corrugation welding process, the crest 610a and the trough 610b of the first corrugated structure 310 are kept at the same position as the crest of the second corrugated structure 610. The positions of the wave trough 610a and the wave trough 610b are consistent, and an air layer 320 is formed between the first corrugated structure 310 and the glass fiber tape 400, and between the second corrugated structure 610 and the silica aerogel coating 500. At the same time, during the second corrugation welding process, the heat generated during the argon arc welding of the copper tube is used to dry the silica aerogel coating 500 coated on the surface of the glass fiber tape 400, effectively ensuring the coating effect and adhesion firmness of the aerogel coating, and further improving the reliability of the product.

[0072] It should be noted that by performing a second corrugation welding process on the outer side of the glass fiber tape 400 and the aerogel layer, the RF coaxial cable is formed into a structure with a double-layer corrugated copper tube, which not only enhances the mechanical strength of the cable, but also further improves the thermal insulation effect; during the two corrugation welding processes, it is ensured that the peaks 610a of the first outer conductor 300 and the second outer conductor 600 are accurately aligned with each other, and the troughs 610b are accurately aligned with each other, so that a uniform and stable air layer 320 is formed between the two layers of corrugated copper tubes. An air layer 320 is added between the inner and outer corrugated conductor layers. Utilizing the excellent thermal insulation properties of air, the thermal insulation between the two layers is significantly enhanced, preventing the insulating foam layer 200 (melting temperature between 100-140°C) from melting and ensuring effective signal transmission. Furthermore, the coordinated combination of the glass fiber tape 400, the silica aerogel layer, and the air layer 320 greatly enhances the flame retardancy and thermal insulation properties of the cable's middle section, achieving a synergistic superposition of material efficiencies and achieving thermal insulation and flame retardancy far exceeding that achieved by the addition of a single material.

[0073] S7. Flame-retardant and fire-resistant layer wrapping: Using concentric wrapping, wrap the fireproof cloth 700 and mica tape 800 around the surface of the second outer conductor 600 to form a second semi-finished structure with an outer diameter of 27.3mm ± 0.30mm. The flame-retardant and fire-resistant layer effectively enhances the flame-retardant and thermal insulation properties of the cable's outer layer, continuously blocking the transfer of external heat inward, further ensuring the cable's safe operation in extremely high-temperature environments.

[0074] In this embodiment, NOMEX fireproof cloth is used, and its thickness is 1mm-1.5mm. The thickness of the mica tape 800 is 0.14mm±0.01mm and the width is 45mm±1mm. The overlap rate of the fireproof cloth 700 and the mica tape 800 is 30%~50%.

[0075] S8. Sheath extrusion: A low-smoke, halogen-free, flame-retardant sheath material with a density of 1.50±0.1g / cm³ is pushed through an extruder head and a dedicated extrusion die and coated on the surface of the second semi-finished product structure. The extrusion temperature is 125°C~165°C to form a flame-retardant sheath layer 900 with an outer diameter of 32mm±0.30mm, and finally a finished RF coaxial cable is obtained.

[0076] It should be noted that after each process is completed, semi-finished and finished products are tested to ensure that the performance and appearance of the product meet the design requirements. After passing the test, the product is assembled into trays, packaged, and stored, and a final test is carried out before shipment.

[0077] After the above process, an ultra-high temperature resistant radio frequency coaxial cable is obtained, comprising an inner conductor 100, an insulating foam layer 200, a first outer conductor 300, a glass fiber tape 400, a silica aerogel coating 500, a second outer conductor 600, a flame retardant and fire-resistant layer and a flame retardant sheath layer 900, which are arranged in sequence from the inside to the outside: wherein the insulating foam layer 200 is coated on the surface of the inner conductor 100; the first outer conductor 300 is coated on the surface of the insulating foam layer 200 and has a first corrugated structure 310 including a crest 610a and a trough 610b; the glass fiber tape 400 is wrapped around the surface of the first outer conductor 300; the silica aerogel coating 500 is coated on the surface of the glass fiber tape 400 layer; the second outer conductor 600 is coated on the surface of the insulating foam layer 200; 00 is coated on the surface of the silica aerogel coating 500, and has a second corrugated structure 610 including crests 610a and troughs 610b; the flame retardant and fire-resistant layer includes a fireproof cloth 700 and a mica tape 800 sequentially wrapped around the surface of the second outer conductor 600; the flame retardant sheath layer 900 is coated on the surface of the flame retardant and fire-resistant layer; wherein the positions of the crests 610a and troughs 610b of the first corrugated structure 310 are consistent with the positions of the crests 610a and troughs 610b corresponding to the second corrugated structure 610, and an air layer 320 is formed between the first corrugated structure 310 and the glass fiber tape 400, and between the second corrugated structure 610 and the silica aerogel coating 500.

[0078] The ultra-high temperature resistant RF coaxial cable manufactured above was passed through the NH-2 fire resistance combustion test device in accordance with the national standard of the People's Republic of China (GB / T 19216.11-"Line integrity test of electric or optical cables under fire conditions" Part 11: Test device - Single fire with a flame temperature not less than 750°C). After continuous combustion for 4 hours under a 750°C flame environment, neither the inner conductor 100 nor the outer conductor showed any structural abnormality or damage. The performance of the RF coaxial cable before and after combustion was tested, as shown in Table 1 and Figures 5 to 10 As shown, all performance parameters (constant, standing wave, and impedance) remained unchanged, maintaining normal electrical performance and signal transmission capabilities. As shown in Table 1, the maximum attenuation constant before and after combustion did not exceed 0.01 (the standard maximum attenuation constant refers to the value for a 100-meter cable length at 20°C).

[0079] Table 1: Comparison of maximum decay constants before and after combustion

[0080] .

[0081] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for manufacturing an ultra-high temperature resistant radio frequency coaxial cable, characterized in that: include: providing an inner conductor; Preparation of the insulating foam layer: a high-density foaming material, a low-density foaming material and a nucleating agent are mixed in a set mass ratio, and carbon dioxide gas is injected at the same time. A special extrusion die is used in conjunction with an extruder head to push and form a uniformly distributed foam structure on the outer surface of the inner conductor. After cooling and shaping in a hot water tank and a cold water tank in sequence, an insulating foam layer covering the outer surface of the inner conductor is obtained; Forming the first outer conductor: performing a first corrugation welding process on the outer surface of the insulating foam layer, including sequentially subjecting the copper strip to cleaning, cutting, preforming, copper tube forming, copper tube welding, and eccentric rolling to form a first outer conductor coated on the outer surface of the insulating foam layer, the first outer conductor having a first corrugated structure including crests and troughs; Glass fiber tape wrapping: using concentric wrapping equipment to wrap the glass fiber tape around the surface of the first outer conductor to form a first semi-finished product structure; Silica aerogel spraying: spraying a silica aerogel coating evenly on the surface of the glass fiber tape; Forming the second outer conductor: performing a second corrugation welding process on the outer surface of the silica aerogel coating to form a second outer conductor, wherein the second outer conductor has a second corrugated structure including crests and troughs; wherein, during the second corrugation welding process, the positions of the crests and troughs of the first corrugated structure are maintained consistent with the positions of the corresponding crests and troughs of the second corrugated structure, and air layers are formed between the first corrugated structure and the glass fiber tape, and between the second corrugated structure and the silica aerogel coating; simultaneously, during the second corrugation welding process, the silica aerogel coating coated on the surface of the glass fiber tape is dried using the heat generated during the argon arc welding of the copper tube; Flame retardant and fire resistant layer wrapping: concentric wrapping is adopted to wrap the fireproof cloth and mica tape around the surface of the second outer conductor in sequence to form a second semi-finished product structure; Sheath extrusion: The low-smoke halogen-free flame-retardant sheath material is pushed through an extruder head and a special extrusion die and coated on the surface of the second semi-finished product structure to form a flame-retardant sheath layer, and finally a finished RF coaxial cable is obtained.

2. The method for manufacturing an ultra-high temperature resistant radio frequency coaxial cable according to claim 1, wherein: The inner conductor is made of copper-clad aluminum.

3. The method for manufacturing an ultra-high temperature resistant radio frequency coaxial cable according to claim 2, wherein: The high-density foaming material, the low-density foaming material and the nucleating agent are mixed in a mass ratio of 71:25:4, and the outer diameter of the insulating foaming layer is 12.6 mm±0.20 mm.

4. The method for manufacturing an ultra-high temperature resistant radio frequency coaxial cable according to claim 3, wherein: The diameter of the first outer conductor is 13.9 mm ± 0.30 mm, and the trough diameter is 12.1 mm ± 0.50 mm; the diameter of the second outer conductor is 17.2 mm ± 0.30 mm.

5. The method for manufacturing an ultra-high temperature resistant radio frequency coaxial cable according to claim 4, characterized in that: The overlapping rate of the glass fiber tape is 30% to 50%, and the outer diameter of the first semi-finished product structure is 14.8 mm ± 0.20 mm.

6. The method for manufacturing an ultra-high temperature resistant radio frequency coaxial cable according to claim 5, characterized in that: The spraying thickness of the silica aerogel coating is 0.3 mm to 1.0 mm.

7. The method for manufacturing an ultra-high temperature resistant radio frequency coaxial cable according to claim 6, characterized in that: The fireproof cloth is NOMEX fireproof cloth with a thickness of 1mm-1.5mm. The mica tape has a thickness of 0.14mm±0.01mm and a width of 45mm±1mm.

8. The method for manufacturing an ultra-high temperature resistant radio frequency coaxial cable according to claim 7, wherein: The overlapping rates of the fireproof cloth and the mica tape are both 30% to 50%, and the outer diameter of the second semi-finished product structure is 27.3 mm ± 0.30 mm.

9. The method for manufacturing an ultra-high temperature resistant radio frequency coaxial cable according to claim 8, characterized in that: The density of the low-smoke halogen-free flame-retardant sheath material is 1.50±0.1g / cm³, and the extrusion temperature is 125°C~165°C; the outer diameter of the flame-retardant sheath layer is 32mm±0.30mm.

10. An ultra-high temperature resistant radio frequency coaxial cable, characterized in that: The method for manufacturing an ultra-high temperature resistant radio frequency coaxial cable according to any one of claims 1 to 9 comprises: inner conductor; an insulating foam layer, covering the surface of the inner conductor; a first outer conductor, coated on the surface of the insulating foam layer, and having a first corrugated structure including crests and troughs; A glass fiber tape wrapped around the surface of the first outer conductor; A silica aerogel coating is applied to the surface of the glass fiber tape layer; A second outer conductor, coated on the surface of the silica aerogel coating, has a second corrugated structure including crests and valleys; a flame retardant and fire resistant layer comprising a fireproof cloth and a mica tape sequentially wrapped around the surface of the second outer conductor; a flame retardant sheath layer, covering the surface of the flame retardant and fire resistant layer; The positions of the crests and troughs of the first corrugated structure are consistent with the positions of the corresponding crests and troughs of the second corrugated structure, and air layers are formed between the first corrugated structure and the glass fiber tape, and between the second corrugated structure and the silica aerogel coating.

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