A high-pressure-resistant low-loss radio frequency coaxial cable

Abstract

The application belongs to the technical field of radio frequency coaxial cables, and specifically discloses a high-pressure-resistant and low-loss radio frequency coaxial cable, which comprises, from inside to outside, an inner conductor, an insulating layer, an outer conductor, an inner protective layer and a finished protective jacket, wherein the outer conductor is in a corrugated structure and has spaced-apart wave crests and wave troughs; the inner protective layer is made of a low-smoke halogen-free flame-retardant material and is completely filled in the wave troughs of the outer conductor and coated on the surfaces of the wave crests; and the inner protective layer is formed through a double-screw double-spiral-hole extrusion type extrusion process, wherein the extrusion temperature and pressure of the screw and the spiral hole corresponding to the wave crests are independently controlled from the extrusion temperature and pressure of the screw and the spiral hole corresponding to the wave troughs. The radio frequency coaxial cable can not only improve the pressure resistance of the cable but also reduce the overall transmission loss of the cable.

Description

Technical Field

[0001] This application belongs to the field of radio frequency coaxial cable technology, and more specifically, relates to a high voltage resistance and low loss radio frequency coaxial cable. Background Technology

[0002] As a core component for high-frequency signal transmission, radio frequency (RF) coaxial cables directly determine the stability and reliability of signal transmission through their mechanical properties (especially compressive strength) and transmission performance (loss characteristics). They are widely used in wireless communication, broadcasting, television, and radar systems. A typical RF coaxial cable structure usually includes an inner conductor, an insulation layer, an outer conductor, and a finished sheath. The outer conductor often employs a corrugated structure (including crests and troughs), ensuring both cable flexibility and effective shielding to reduce signal interference and radiation loss.

[0003] In existing RF coaxial cable manufacturing processes, after the outer conductor is produced, the cable directly enters the finished sheath processing stage. This involves extruding the sheath material onto the outer conductor to form a complete outer protective structure. However, this traditional process has significant technical drawbacks: due to the structural differences between the crests and troughs of the outer conductor, during finished sheath processing, the sheath material mainly adheres to the crest surface, making it difficult to fully fill the troughs, resulting in gaps or incomplete filling.

[0004] The aforementioned structural defects directly lead to poor compressive strength of the cable: when the cable is subjected to external pressure, the force mainly acts on the crests of the outer conductor, while the troughs, due to insufficient filling, cannot effectively distribute the external force, easily causing the crests to deform and collapse, thereby damaging the internal structure of the cable (such as insulation layer damage and inner conductor displacement), affecting signal transmission, and even causing the cable to be scrapped. To compensate for the insufficient compressive strength, existing technologies generally use methods such as increasing the thickness of the outer conductor copper and reducing the corrugation pitch to strengthen it—by thickening the outer conductor copper layer, its own structural strength is improved, thereby resisting external pressure and meeting basic compressive strength requirements. However, this method has significant drawbacks: on the one hand, it greatly increases the amount of outer conductor copper used, increasing production costs; on the other hand, it exacerbates conductor loss caused by the skin effect, and the excessively thick crest structure also increases reflection loss during signal transmission, leading to a decrease in the overall loss performance of the cable. Ultimately, it cannot meet the dual requirements of compressive strength and low loss, nor does it conform to the industry development trend of energy conservation and emission reduction.

[0005] In addition, although some existing cables have inner sheaths, they mostly use ordinary extrusion processes. Even if an inner sheath is installed, it is still necessary to increase the thickness of the outer conductor copper to ensure compressive strength. This makes it impossible to simultaneously improve compressive strength and loss performance, and it is difficult to meet the stringent requirements of high-end applications for the overall performance of cables. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this application is to provide a high-pressure-resistant and low-loss radio frequency coaxial cable, which aims to solve the problem that the existing radio frequency coaxial cable processing technology relies on increasing the thickness of the outer conductor copper to ensure pressure resistance, resulting in the radio frequency coaxial cable being unable to balance pressure resistance and loss performance.

[0007] To achieve the above objectives, in a first aspect, this application provides a high-voltage-resistance, low-loss radio frequency coaxial cable, comprising, from the inside out, an inner conductor, an insulation layer, an outer conductor, an inner sheath, and a finished sheath, wherein: The outer conductor has a corrugated structure with alternating peaks and troughs; The inner protective layer is made of low-smoke halogen-free flame retardant and completely fills the trough of the outer conductor, while also covering the surface of the crest. The inner protective layer is formed by a twin-screw twin-cylinder extrusion process. In the twin-screw twin-cylinder extrusion process, the extrusion temperature and extrusion pressure of the screw and cylinder corresponding to the crest are independently controlled, as are the extrusion temperature and extrusion pressure of the screw and cylinder corresponding to the trough.

[0008] This application provides a high-pressure-resistance, low-loss radio frequency coaxial cable. The inner sheath employs a twin-screw, twin-cylinder extrusion process, which fully fills the troughs of the outer conductor while maintaining the overall outer diameter of the cable. When the cable is subjected to external pressure, the force is evenly distributed through the inner sheath material at the troughs, preventing the force from concentrating on the outer conductor crest. This effectively prevents crest deformation and collapse, thereby protecting the internal insulation layer and inner conductor, increasing the cable's pressure resistance, and enabling it to withstand greater external pressure. There is no need to increase the outer conductor copper thickness to meet the pressure resistance requirements, reducing the amount of copper used in the outer conductor. This reduces conductor loss caused by the skin effect and reduces reflection loss during signal transmission. Combined with the low dielectric loss characteristics of the insulation layer, the overall transmission loss of the cable is reduced, resulting in more stable and efficient signal transmission. The reduced copper usage significantly lowers production costs, aligning with the industry trend of energy conservation and emission reduction. The inner sheath uses low-smoke, halogen-free flame-retardant material, which releases no halogens, low smoke, or toxic gases during combustion, enhancing safety and environmental friendliness. The low-smoke, halogen-free flame-retardant inner sheath adheres tightly to the crests and troughs of the outer conductor, not only improving compressive strength and flame retardancy but also enhancing the structural stability of the outer conductor, preventing deformation during bending and stretching. It also reduces adhesion between the inner sheath, the outer conductor, and the finished sheath, facilitating subsequent construction and maintenance, and extending the cable's service life without relying on copper layer thickness to maintain structural stability.

[0009] According to the present application, a high-voltage-resistant, low-loss radio frequency coaxial cable is provided, wherein the low-smoke, halogen-free retardant fuel comprises 30%-70% by weight of filler masterbatch, wherein the filler masterbatch is based on polyolefin resin powder and contains white micron-sized inorganic mineral powder and related additives.

[0010] The high-pressure-resistant, low-loss radio frequency coaxial cable provided in this application adopts a mixed system of filler masterbatch and low-smoke halogen-free flame retardant. This system utilizes the supporting strength and cost advantages of inorganic mineral powder while ensuring the flame retardant and environmental performance of the material. This ratio provides a good balance between extrusion processability, mechanical support performance and flame retardant performance of the material, ensuring that the inner sheath can be reliably formed and function.

[0011] According to the high-pressure-resistant, low-loss radio frequency coaxial cable provided in this application, in the twin-screw, twin-bore extrusion process, the extrusion temperature of the screw and bore corresponding to the wave crest is 170℃-185℃.

[0012] The high-pressure-resistant, low-loss RF coaxial cable provided in this application, in the twin-screw, twin-cylinder extrusion process, controls the extrusion temperature of the screw and cylinder corresponding to the wave peak to be 170℃-185℃, which can improve the smoothness of the coating.

[0013] According to the high-pressure-resistant, low-loss radio frequency coaxial cable provided in this application, in the twin-screw, twin-bore extrusion process, the extrusion temperature of the screw and bore corresponding to the trough is 135℃-170℃.

[0014] The high-pressure-resistant, low-loss radio frequency coaxial cable provided in this application, in the twin-screw, twin-cylinder extrusion process, controls the extrusion temperature of the screw and cylinder corresponding to the trough to be 135℃-170℃, which can improve the filling density.

[0015] According to the high-pressure-resistant, low-loss radio frequency coaxial cable provided in this application, in the twin-screw, twin-bore extrusion process, the extrusion pressure of the screw and bore corresponding to the trough is 18MPa-25MPa.

[0016] The high-pressure-resistant, low-loss RF coaxial cable provided in this application, in the twin-screw, twin-cylinder extrusion process, controls the extrusion pressure of the screw and cylinder corresponding to the trough to be 18MPa-25MPa, which can ensure that the low-smoke, halogen-free, flame-retardant inner sheath material fully fills the trough, uniformly covers the peak, and is free of bubbles and cracks.

[0017] According to the high-pressure-resistant, low-loss radio frequency coaxial cable provided in this application, the extrusion pressure of the screw and screw bore corresponding to the wave crest is 15 MPa - 20 MPa.

[0018] The high-pressure-resistant, low-loss RF coaxial cable provided in this application, in the twin-screw, twin-cylinder extrusion process, controls the extrusion pressure of the screw and cylinder corresponding to the wave peak to be 15 MPa - 20 MPa, which can ensure that the low-smoke, halogen-free, flame-retardant inner sheath material fully fills the troughs, uniformly covers the wave peaks, and is free of bubbles and cracks.

[0019] According to the present application, a high-voltage-resistant, low-loss radio frequency coaxial cable is provided, wherein the finished sheath is made of low-smoke, halogen-free flame-retardant material, covers the outside of the inner sheath, and is compatible with the material of the inner sheath.

[0020] The high-voltage, low-loss radio frequency coaxial cable provided in this application also uses low-smoke, halogen-free flame-retardant sheath, which is compatible with the inner sheath material. Together, they form a complete and unified low-smoke, halogen-free flame-retardant protection system for the cable. This not only further enhances the cable's mechanical protection and flame-retardant performance, but also ensures the consistency and reliability of the overall environmental protection indicators.

[0021] According to the present application, a high-voltage-resistance, low-loss radio frequency coaxial cable is provided, wherein the insulation layer is a low dielectric constant material.

[0022] The high-voltage-resistant, low-loss radio frequency coaxial cable provided in this application uses a low-dielectric-constant material as the insulation layer, which reduces the dielectric loss of the cable from the source. Combined with the optimized outer conductor structure and low-loss process, it achieves a systematic reduction in cable transmission loss and meets the stringent requirements for low-loss transmission of high-frequency signals.

[0023] Overall, the technical solutions conceived in this application have the following advantages compared with the prior art: This application provides a high-pressure-resistance, low-loss radio frequency coaxial cable. The inner sheath employs a twin-screw, twin-cylinder extrusion process, which fully fills the troughs of the outer conductor while maintaining the overall outer diameter of the cable. When the cable is subjected to external pressure, the force is evenly distributed through the inner sheath material at the troughs, preventing the force from concentrating on the outer conductor crest. This effectively prevents crest deformation and collapse, thereby protecting the internal insulation layer and inner conductor, increasing the cable's pressure resistance, and enabling it to withstand greater external pressure. There is no need to increase the outer conductor copper thickness to meet the pressure resistance requirements, reducing the amount of copper used in the outer conductor. This reduces conductor loss caused by the skin effect and reduces reflection loss during signal transmission. Combined with the low dielectric loss characteristics of the insulation layer, the overall transmission loss of the cable is reduced, resulting in more stable and efficient signal transmission. The reduced copper usage significantly lowers production costs, aligning with the industry trend of energy conservation and emission reduction. The inner sheath uses low-smoke, halogen-free flame-retardant material, which releases no halogens, low smoke, or toxic gases during combustion, enhancing safety and environmental friendliness. The low-smoke, halogen-free flame-retardant inner sheath adheres tightly to the crests and troughs of the outer conductor, not only improving compressive strength and flame retardancy but also enhancing the structural stability of the outer conductor, preventing deformation during bending and stretching. It also reduces adhesion between the inner sheath, the outer conductor, and the finished sheath, facilitating subsequent construction and maintenance, and extending the cable's service life without relying on copper layer thickness to maintain structural stability. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the cross-sectional structure of the high-voltage-resistance, low-loss radio frequency coaxial cable provided in the embodiments of this application; Figure 2 This is a schematic diagram of the processing technology provided in the embodiments of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0027] In this article, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The symbol " / " in this article indicates that the related objects are in an "or" relationship; for example, A / B means A or B.

[0028] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0029] In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more, for example, multiple processing units means two or more processing units, multiple elements means two or more elements, etc.

[0030] Next, combined Figures 1-2 The high-voltage-resistant, low-loss radio frequency coaxial cable provided in the embodiments of this application is described.

[0031] Figure 1 This is a schematic diagram of the cross-sectional structure of the high voltage resistance and low loss radio frequency coaxial cable provided in the embodiments of this application, as shown below. Figure 1 As shown, the high-voltage-resistance, low-loss radio frequency coaxial cable comprises, from the inside out, an inner conductor, an insulation layer, an outer conductor, an inner sheath, and a finished sheath, wherein: The outer conductor has a corrugated structure with alternating peaks and troughs; The inner protective layer is made of low-smoke halogen-free flame retardant and completely fills the trough of the outer conductor, while also covering the surface of the crest. The inner protective layer is formed by a twin-screw twin-cylinder extrusion process. In the twin-screw twin-cylinder extrusion process, the extrusion temperature and extrusion pressure of the screw and cylinder corresponding to the crest are independently controlled, as are the extrusion temperature and extrusion pressure of the screw and cylinder corresponding to the trough.

[0032] Figure 2 This is a schematic flowchart of the processing technology provided in the embodiments of this application, such as... Figure 2 As shown, the core improvement of this application lies in optimizing the processing technology of radio frequency coaxial cables, adding an inner sheath processing step before the finished sheath processing, and using low-smoke halogen-free flame arrestor to replace the existing compressive strength enhancement method of "increasing the thickness of the outer conductor copper".

[0033] like Figure 1 As shown, the radio frequency coaxial cable provided in this application still retains the traditional core structure, which includes, from the inside out, an inner conductor, an insulation layer, an outer conductor, an inner sheath, and a finished sheath.

[0034] The outer conductor has a corrugated structure with alternating peaks and troughs.

[0035] Optionally, the specific parameters of the corrugated structure can be adjusted according to the cable specifications and usage scenarios.

[0036] Alternatively, the outer conductor can be made of copper, which is formed by processing copper strips. This can meet the requirements for shielding and conductivity, and there is no need to increase the thickness of the outer conductor copper to improve the compressive strength.

[0037] This application adds an inner sheath processing step after the outer conductor production is completed and before the finished sheath processing. This step adopts a twin-screw twin-cylinder extrusion process (two sets of screws and cylinders are independently controlled and work together), which can adapt to the differentiated extrusion requirements of the outer conductor crest and trough, effectively solving the technical problem that the traditional single-screw single-cylinder cannot achieve separate control of crest and trough extrusion.

[0038] The core requirement of this process is to ensure that the overall outer diameter of the cable is consistent with that of existing traditional cables, and to fully fill the troughs of the outer conductor with low-smoke halogen-free flame-retardant inner sheath material through differentiated control of twin screws and twin bores, while forming a uniform coating layer on the surface of the crests. This achieves a tight fit between the inner sheath and the crests and troughs of the outer conductor, without gaps or looseness. By distributing external forces through the inner sheath, the existing method of "increasing the thickness of the outer conductor copper" is replaced, thereby improving the compressive strength and achieving low-smoke halogen-free flame-retardant effect.

[0039] The low-smoke, halogen-free, flame-retardant inner sheath adheres tightly to the crests and troughs of the outer conductor, which not only improves the compressive strength and flame-retardant properties, but also enhances the structural stability of the outer conductor, preventing deformation during bending and stretching. At the same time, it reduces adhesion between the inner sheath and the outer conductor and the finished sheath, facilitating subsequent construction and maintenance, and extending the cable's service life. It does not rely on the thickness of the copper layer to maintain structural stability.

[0040] Optionally, based on the improved compressive strength brought about by the inner sheath filling, there is no need to further enhance the compressive strength by increasing the thickness of the outer conductor copper. Therefore, the outer conductor crest structure can be optimized. The specific optimization method is as follows: under the premise of ensuring the shielding performance and structural stability of the outer conductor, the height and thickness of the crest can be appropriately reduced (without increasing the copper layer). For example, the crest height can be reduced by 0.1-0.2 mm, and the outer conductor thickness can be reduced by 0.03-0.05 mm. Alternatively, the crest spacing can be increased, for example, the crest spacing can be increased by 0.1-0.2 mm.

[0041] The optimized outer conductor crest structure can reduce the amount of copper conductor used, reduce conductor loss caused by the skin effect, and reduce signal reflection at the crest, thereby reducing reflection loss and improving the low-loss performance of the cable, while further reducing production costs (reducing the amount of copper used).

[0042] After the outer conductor crest structure is optimized (without the need to thicken the copper layer), its shielding performance is not affected. It can still effectively block external electromagnetic interference and reduce internal signal radiation. Combined with the auxiliary shielding effect of the low-smoke halogen-free inner sheath, the shielding effect of the cable can be maintained above -75dB, meeting the shielding requirements of high-end communication scenarios and achieving the effect of "no copper layer thickening, no shielding reduction, and no environmental hazards".

[0043] The high-pressure-resistance, low-loss RF coaxial cable provided in this application employs a twin-screw, twin-cylinder extrusion process for its inner sheath. This process ensures the overall outer diameter of the cable remains constant while fully filling the troughs of the outer conductor. When the cable is subjected to external pressure, the force is evenly distributed through the inner sheath material at the troughs, preventing concentrated force on the outer conductor crests. This effectively prevents crest deformation and collapse, thus protecting the internal insulation layer and inner conductor, increasing the cable's pressure resistance, and allowing it to withstand greater external pressure. There is no need to increase the outer conductor copper thickness to meet pressure resistance requirements, reducing the amount of copper used in the outer conductor. This reduces conductor loss caused by the skin effect and reduces reflection loss during signal transmission. Combined with the low dielectric loss characteristics of the insulation layer, this reduces overall cable transmission loss, resulting in more stable and efficient signal transmission, while also reducing... The reduced copper usage significantly lowers production costs, aligning with the industry trend of energy conservation and emission reduction. The inner sheath uses low-smoke, halogen-free flame-retardant material, which releases no halogens, low smoke, or toxic gases during combustion, enhancing safety and environmental friendliness. The low-smoke, halogen-free flame-retardant inner sheath adheres tightly to the crests and troughs of the outer conductor, not only improving compressive strength and flame retardancy but also enhancing the structural stability of the outer conductor, preventing deformation during bending and stretching. It also reduces adhesion between the inner sheath, the outer conductor, and the finished sheath, facilitating subsequent construction and maintenance, and extending the cable's service life without relying on copper layer thickness to maintain structural stability.

[0044] In some embodiments, the low-smoke halogen-free retardant fuel comprises 30%-70% by weight of filler masterbatch, wherein the filler masterbatch is based on polyolefin resin powder and contains white micron-sized inorganic mineral powder and related additives.

[0045] The inner sheath material is selected from low-smoke halogen-free flame that is compatible with the finished sheath and has a certain compressive strength. It can be a mixed material made of 30%-70% filler masterbatch and 70%-30% low-smoke halogen-free flame by weight.

[0046] The filler masterbatch is made of polyolefin resin powder as the matrix, and is made of white micron-sized inorganic mineral powder and related additives. The low-smoke halogen-free flame retardant must comply with the GB / T 19666-2019 standard "General Rules for Flame Retardant and Fire-Resistant Wires, Cables or Optical Cables", and has the characteristics of low smoke, halogen-free, flame retardant and environmentally friendly.

[0047] Optionally, the low-smoke halogen-free flame retardant material can be selected from conventional low-smoke halogen-free flame retardant polymer materials with different formulations according to actual needs, as long as it can achieve trough filling, has certain compressive strength and flame retardant performance, and the inner protective layer is compatible with the finished sheath material.

[0048] In some embodiments, in the twin-screw twin-bore extrusion process, the extrusion temperature of the screw and bore corresponding to the wave crest is 170℃-185℃.

[0049] The twin-screw twin-cylinder extrusion process uses a dedicated extruder with two sets of screws and cylinders that have independently adjustable parameters. The extrusion temperature of the screw and cylinder corresponding to the peak is controlled at 170℃-185℃, which can improve the smoothness of coating.

[0050] In some embodiments, in the twin-screw twin-bore extrusion process, the extrusion temperature of the screw and bore corresponding to the trough is 135℃-170℃.

[0051] The trough corresponds to the extrusion temperature of the screw and screw chamber being controlled at 135℃-170℃, which can improve the filling density.

[0052] In some embodiments, in the twin-screw twin-bore extrusion process, the extrusion pressure of the screw and bore corresponding to the trough is 18MPa-25MPa.

[0053] The extrusion pressure adopts a dynamic adjustment mode, and the screw bore pressure is controlled at 18-25MPa for trough filling. In some embodiments, in the twin-screw twin-bore extrusion process, the extrusion pressure of the screw and bore corresponding to the crest is 15 MPa - 20 MPa.

[0054] The pressure of the screw bore is controlled at 15-20MPa to ensure that the low-smoke halogen-free flame-retardant inner protective layer material fully fills the troughs and uniformly covers the crests, without bubbles or cracks.

[0055] In some embodiments, the finished sheath is made of low-smoke halogen-free flame arrestor, covers the outside of the inner sheath, and is compatible with the material of the inner sheath.

[0056] After the inner sheath is processed, the finished sheath is processed according to the existing conventional process, and the low smoke halogen-free flame retardant sheath material is wrapped on the outside of the inner sheath to form a complete cable outer layer protection structure.

[0057] Optionally, the finished sheath is tightly fitted to the inner sheath, which can further improve the mechanical protection and flame retardant performance of the cable without increasing the thickness of the sheath or the outer conductor copper. Moreover, the low-smoke halogen-free flame retardant material used in the finished sheath is compatible with the inner sheath material, ensuring consistent flame retardant effect throughout the cable. Both the inner sheath and the finished sheath use low-smoke halogen-free flame retardant material, which releases no halogen, low smoke, and no toxic or harmful gases during combustion. The smoke toxicity level reaches ZA1, the smoke density level is ≤100, and the flame retardant level reaches B1. This material has good compressive strength, flame retardant performance, and environmental protection performance. It releases no toxic or harmful smoke during combustion, which can meet the safety and environmental protection requirements of high-end scenarios such as rail transit, high-rise buildings, and nuclear power, effectively expanding the applicable scenarios of the cable.

[0058] In some embodiments, the insulating layer is a low dielectric constant material.

[0059] Alternatively, the insulation layer can be made of a low dielectric constant material, such as foamed polyethylene, which can effectively reduce dielectric loss.

[0060] In one embodiment 1 of this application, the specific process steps for fabricating the radio frequency coaxial cable are as follows: 1. Copper-clad aluminum wire with a diameter of 4.85mm is selected as the inner conductor. It is directly drawn and rounded to ensure the conductivity and structural roundness of the inner conductor. A foamed polyethylene insulation layer (88% foaming degree) is extruded on the outside of the inner conductor using a physical foaming process. The outer diameter of the insulation layer is reasonably set to match the size of the inner conductor to ensure low dielectric loss. A corrugated outer conductor is formed by longitudinally wrapping and welding copper strip and then rolling it. Its copper layer thickness is 0.21mm (no thickening required), the outer diameter of the crest is 13.90mm, the outer diameter of the trough is 12.10mm, and the pitch is 5.10mm. The overall structural dimensions of the outer conductor are precisely controlled. 2. After the outer conductor is produced, the inner sheath is processed using a twin-screw, twin-cylinder extrusion process (with an online thickness closed-loop feedback module). The inner sheath material is a mixture of 50% filler masterbatch (polyolefin resin powder as the matrix, containing white micron-sized inorganic mineral powder and additives) and 50% low-smoke halogen-free flame retardant (compliant with GB / T 19666-2019 standard). The extruder crest corresponds to a screw bore temperature of 185℃, and the trough corresponds to a screw bore temperature of 135℃. The extrusion pressure is dynamically adjusted (trough 20MPa, crest 18MPa), and the parameters are finely adjusted in real time using an online laser thickness gauge to ensure that the inner sheath fully fills the troughs and crests of the outer conductor and uniformly covers them. After coating, the overall outer diameter is controlled within a reasonable range (consistent with the outer diameter of traditional cables of the same specification). 3. Relying on the compressive support of the inner sheath, there is no need to thicken the outer conductor copper layer (keeping it unchanged at 0.21mm). By appropriately optimizing the peak height in combination with the original size of the outer conductor, the peak spacing is adjusted to 6.0mm. After optimization, the shielding performance of the outer conductor is not affected, and the amount of copper used is reduced by 12%, which is significantly lower than the traditional solution of thickening the copper layer. 4. After the inner sheath is processed, the low-smoke halogen-free flame-retardant sheath material is wrapped on the outside of the inner sheath (thickness 0.8mm) using conventional extrusion process. The overall cable outer diameter is reasonably controlled according to the size after the inner sheath is wrapped (consistent with traditional cables of the same specification), and the cable preparation is completed. The sheath and inner sheath materials are compatible to ensure the overall flame-retardant effect. 5. The cable of Example 1 was compared with a traditional thickened outer conductor copper layer cable in a test, and the results are as follows: Compressive strength: 1800N / 100mm in this embodiment, slightly better than traditional cables (1750N / 100mm), and no need to thicken the copper layer; Transmission loss: 0.85dB / 100m in this embodiment at 2GHz frequency, a 35.6% reduction compared to traditional cables (1.32dB / 100m); Shielding performance: The shielding attenuation in this embodiment is -82dB, which is basically the same as that of traditional cables (-81dB); Flame retardant and environmentally friendly: smoke toxicity level ZA1, smoke density ≤85, flame retardant level B1; Structural stability: No deformation of the outer conductor or damage to the insulation layer after 1000 bending tests, superior to traditional cables; Production costs: The amount of copper used in the outer conductor is reduced by 12%, resulting in an overall cost reduction of 13% compared to the traditional solution.

[0061] In one embodiment 2 of this application, the difference from embodiment 1 is as follows: the inner sheath material is composed of 30% filler masterbatch and 70% low-smoke halogen-free fuel by weight. In the twin-screw twin-cylinder extrusion process, the screw cylinder temperature corresponding to the crest is set to 180°C, and the screw cylinder temperature corresponding to the trough is set to 135°C. The extrusion pressure is dynamically adjusted (18MPa for trough filling and 15MPa for crest coating). The outer conductor crest height is appropriately optimized (the copper layer thickness remains unchanged at 0.21mm), and the crest spacing is increased to 5.5mm. The cable of embodiment 2 is compared with a traditional thickened outer conductor copper layer cable, and the results are as follows: The compressive strength is 1650N / 100mm, which is close to that of existing traditional thickened copper layer cables (1750N / 100mm), meeting the compressive strength requirements without increasing the thickness of the outer conductor copper. The transmission loss at 2GHz frequency is 0.92dB / 100m, which is 31.8% lower than that of existing traditional thickened copper layer cables. The shielding attenuation is -80dB, and the structural stability is good. The flame retardant and environmentally friendly performance is: smoke toxicity level ZA1, smoke density ≤90, and flame retardant level B1. The amount of copper used in the outer conductor is reduced by 8%, and the production cost is reduced by 10% compared to the traditional thickened copper layer solution.

[0062] In one embodiment 3 of this application, the difference from embodiment 1 is as follows: the inner sheath material is composed of 70% filler masterbatch and 30% low-smoke halogen-free fuel by weight. In the twin-screw twin-cylinder extrusion process, the screw cylinder temperature corresponding to the crest is set to 185°C, and the screw cylinder temperature corresponding to the trough is set to 140°C. The extrusion pressure is dynamically adjusted (the screw cylinder pressure corresponding to trough filling is 25MPa, and the screw cylinder pressure corresponding to crest coating is 20MPa). The outer conductor crest height is appropriately optimized (the copper layer thickness remains unchanged at 0.21mm), and the crest spacing is increased to 6.5mm. The cable of this embodiment 3 is compared with the traditional thickened outer conductor copper layer cable, and the results are as follows: With a compressive strength of 1920N / 100mm, superior to existing traditional thickened copper layer cables (1750N / 100mm), it eliminates the need to increase the thickness of the outer conductor copper. Transmission loss at 2GHz is 0.80dB / 100m, a 39.4% reduction compared to existing traditional thickened copper layer cables. Shielding attenuation is -79dB, demonstrating good structural stability. Flame retardant and environmentally friendly performance: smoke toxicity ZA1 level, smoke density ≤80, flame retardant rating B1. The amount of outer conductor copper used is reduced by 15%, resulting in a 15% reduction in production costs compared to traditional thickened copper layer solutions.

[0063] The processing technology of this application is compatible with existing RF coaxial cable production lines, without the need for a new dedicated production line. It only requires upgrading the existing single-screw extruder to a twin-screw twin-cylinder extruder and adding an online thickness detection feedback module. The modification is simple, the cost is controllable, and it is suitable for large-scale industrial production. At the same time, it completely solves the technical problems of existing technologies such as "pressure resistance depends on copper layer thickness, high cost, high loss, and poor environmental performance".

[0064] It is understood that the various numerical designations used in the embodiments of this application are merely for the convenience of description and are not intended to limit the scope of the embodiments of this application.

[0065] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A high-voltage-resistance, low-loss radio frequency coaxial cable, characterized in that, From the inside out, it includes an inner conductor, an insulating layer, an outer conductor, an inner sheath, and a finished sheath, wherein: The outer conductor has a corrugated structure with alternating peaks and troughs; The inner protective layer is made of low-smoke halogen-free flame retardant and completely fills the trough of the outer conductor, while also covering the surface of the crest. The inner protective layer is formed by a twin-screw twin-cylinder extrusion process. In the twin-screw twin-cylinder extrusion process, the extrusion temperature and extrusion pressure of the screw and cylinder corresponding to the crest are independently controlled, as are the extrusion temperature and extrusion pressure of the screw and cylinder corresponding to the trough.

2. The high-voltage-resistance, low-loss radio frequency coaxial cable according to claim 1, characterized in that, The low-smoke halogen-free retardant fuel comprises 30%-70% filler masterbatch by weight, wherein the filler masterbatch is based on polyolefin resin powder and contains white micron-sized inorganic mineral powder and related additives.

3. The high-voltage-resistance, low-loss radio frequency coaxial cable according to claim 1, characterized in that, In the twin-screw twin-bore extrusion process, the extrusion temperature of the screw and bore corresponding to the wave crest is 170℃-185℃.

4. The high-voltage-resistance, low-loss radio frequency coaxial cable according to claim 1, characterized in that, In the twin-screw twin-bore extrusion process, the extrusion temperature of the screw and bore corresponding to the trough is 135℃-170℃.

5. The high-voltage-resistance, low-loss radio frequency coaxial cable according to claim 1, characterized in that, In the twin-screw twin-bore extrusion process, the extrusion pressure of the screw and bore corresponding to the trough is 18 MPa - 25 MPa.

6. The high-voltage-resistance, low-loss radio frequency coaxial cable according to claim 1, characterized in that, In the twin-screw twin-bore extrusion process, the extrusion pressure of the screw and bore corresponding to the wave crest is 15 MPa - 20 MPa.

7. The high-voltage-resistance, low-loss radio frequency coaxial cable according to claim 1, characterized in that, The finished sheath is made of low-smoke halogen-free flame retardant material, covers the outside of the inner sheath, and is compatible with the material of the inner sheath.

8. The high-voltage-resistance, low-loss radio frequency coaxial cable according to claim 1, characterized in that, The insulating layer is made of a low dielectric constant material.

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