Low-loss radio frequency coaxial cable with high temperature phase stability and method of making same

Abstract

The application relates to the technical field of radio frequency microwave transmission lines, in particular to a radio frequency coaxial cable with high temperature phase stability and low loss and a preparation method thereof, which comprises an inner conductor, a dielectric body, an outer conductor, an intermediate body, an outer shielding body and a sheath; the cross section of the dielectric body is in lotus core structure, the lotus core structure comprises an inner conductor wrapping layer, an outer conductor supporting layer concentrically arranged outside the inner conductor wrapping layer, and a plurality of reinforcing ribs are arranged at equal angles along the center of the inner conductor wrapping layer and the outer conductor supporting layer; and the reinforcing ribs, the inner conductor wrapping layer and the outer conductor supporting layer form fan-shaped through holes therebetween. The application solves the problem that the phase stability, transmission loss and mechanical phase of the radio frequency cable in the prior art cannot be considered simultaneously.

Description

Low-loss RF coaxial cable with high temperature phase stability and its fabrication method Technical Field

[0001] This invention relates to the field of radio frequency microwave transmission line technology, and in particular to a radio frequency coaxial cable with high temperature phase stability and low loss, and a method for its fabrication. Background Technology

[0002] Radio frequency (RF) coaxial cables are key components in modern communication, radar, aerospace, and test and measurement systems. With the development of technologies such as 5G / 6G communication, millimeter-wave radar, and satellite links, higher demands are placed on the performance of RF cables, especially phase stability and transmission loss. In phased array systems, signal phase consistency directly determines beam pointing accuracy and system performance; in long-distance transmission, low loss means less signal attenuation and higher system efficiency.

[0003] In existing technologies, PTFE microporous tape is commonly used as the insulation medium in stable phase cables. However, the uniformity of the microporous tape thickness and the precision of the wrapping equipment can cause significant fluctuations in the dielectric diameter and velocity, resulting in poor phase consistency in the cable. Furthermore, PTFE undergoes a crystal structure phase transition at 19°C, changing from a triclinic to a hexagonal crystal, forming various helical structures. This change in PTFE crystal structure leads to drastic changes in the dielectric constant and significant phase fluctuations at that temperature, resulting in poor phase stability and repeatability in the cable.

[0004] To reduce cable loss and improve the temperature phase stability of cables, this invention proposes a novel PFA core structure as the insulating medium. PFA, also known as soluble polytetrafluoroethylene, has the same temperature resistance as PTFE and does not undergo crystal structure changes at 19°C, thus reducing cable loss and improving the temperature phase stability of cables.

[0005] Chinese Patent Publication No. CN120388786A discloses a coaxial cable comprising an inner conductor, an insulation layer, an outer conductor, a protective layer, a shielding layer, and a sheath arranged coaxially from the inside out. The insulation layer covers the outer surface of the inner conductor, the outer conductor covers the outer surface of the insulation layer, the protective layer covers the outer surface of the outer conductor, the shielding layer covers the outer surface of the protective layer, and the sheath covers the outer surface of the shielding layer. This arrangement adds a protective layer between the outer conductor and the shielding layer, preventing the shielding layer from rubbing against the outer conductor when the coaxial cable bends. In other words, the protective layer protects the shielding layer from friction, reducing or even preventing the surface metal of the shielding layer from detaching due to friction with the outer conductor, thus increasing the service life of the coaxial cable.

[0006] However, existing technologies still suffer from the problem that phase stability, transmission loss, and mechanical phase cannot be simultaneously addressed in stable phase RF cables. Summary of the Invention

[0007] Therefore, the present invention provides a low-loss radio frequency coaxial cable with high temperature phase stability and a method for manufacturing the same, in order to overcome the problem that the phase stability, transmission loss and mechanical phase of radio frequency cables in the prior art cannot be simultaneously achieved.

[0008] To achieve the above objectives, the present invention provides a low-loss radio frequency coaxial cable with high temperature phase stability, comprising: an inner conductor, a dielectric body, an outer conductor, an intermediate body, an outer shield, and a sheath.

[0009] Furthermore, the cross-section of the dielectric body is a core structure, the core structure including an inner conductor wrapping layer and an outer conductor support layer concentrically disposed outside the inner conductor wrapping layer.

[0010] Several reinforcing ribs are set at equal angles along the center of the core of the inner conductor sheath and the outer conductor support layer; a fan-shaped through hole is formed between the reinforcing ribs, the inner conductor sheath and the outer conductor support layer.

[0011] Furthermore, the ratio of the thickness of the reinforcing rib to the outer diameter of the medium body ranges from 0.05 to 0.12;

[0012] The number of sector-shaped through holes is 6.

[0013] Furthermore, the inner conductor includes a copper core conductor and a silver plating layer on the outer side of the copper core conductor;

[0014] The outer conductor is a silver-plated copper strip with a wrapping structure;

[0015] The intermediate is a polytetrafluoroethylene tape with a wrapping structure;

[0016] The outer shielding body is made of silver-plated copper wire with a braided structure;

[0017] The sheath is made of fluoroplastic.

[0018] On the other hand, the present invention provides a method for fabricating a low-loss radio frequency coaxial cable with high temperature phase stability, comprising:

[0019] Step S1: Soluble polytetrafluoroethylene is injected into an extruder, heated to a preset temperature, and then extruded into a pre-made extrusion mold.

[0020] The inner conductor passes through the center of the extrusion mold;

[0021] Step S2: The medium body is coated on the inner conductor at a preset traction speed and preset extrusion pressure.

[0022] Step S3: Perform a first bending test on several points on the inner conductor after the coating is completed, and obtain the size information of the corresponding cross section at each point to obtain the first deformation characteristic value.

[0023] Step S4: If the coating of the dielectric body on the inner conductor does not meet the preset standard based on the first deformation characteristic value, the coating of the dielectric body is verified according to the second bending test, or the extrusion pressure is adjusted.

[0024] Step S5: Use silver-plated copper strip to wrap around the surface of the dielectric body to form an outer conductor and obtain the equivalent dielectric constant;

[0025] Step S6: If the electromagnetic shielding performance of the outer conductor does not meet the preset standard based on the equivalent dielectric constant, adjust the wrapping gap.

[0026] Step S7: Wrap a polytetrafluoroethylene tape around the outer conductor to form an intermediate.

[0027] Step S8: Cover the outside of the intermediate body with an outer shield and a sheath.

[0028] Further, in step S3, the first bending experiment includes:

[0029] Step S31: Cut a 0.1m long sample, cool it to room temperature and place it flat for 1 hour to obtain the diameter of any end section;

[0030] Step S32: Bend the sample at several points along a specified direction by 90°, obtain the major axis length data of any end section, and repeat the experiment at several specified points.

[0031] Step S33: Determine the first deformation characteristic value based on the average value of the major axis length and the diameter length.

[0032] Furthermore, in response to the first deformation characteristic value being greater than or equal to the first preset deformation characteristic value and less than the second preset deformation characteristic value, and the first deformation characteristic value being greater than or equal to the second preset deformation characteristic value, it is determined that the coating of the medium on the inner conductor does not meet the preset standard;

[0033] If the first deformation characteristic value is greater than or equal to the first preset deformation characteristic value and less than the second preset deformation characteristic value, then a second bending test is performed on the sample to obtain the second deformation characteristic value to verify whether the coating of the medium on the inner conductor meets the preset standard.

[0034] If the first deformation characteristic value is greater than or equal to the second preset deformation characteristic value, then the extrusion pressure is increased;

[0035] The increase in the extrusion pressure is positively correlated with the difference between the first deformation characteristic value and the second preset deformation characteristic value.

[0036] Further, in step S4, the second bending experiment includes:

[0037] Step S41: Bend the sample at several points along a random direction by 90°, obtain the major axis length data of any end section, and repeat the experiment at several designated points.

[0038] Step S42: Determine the second deformation characteristic value based on the variance of the obtained major axis length data.

[0039] Furthermore, the coating of the dielectric body on the inner conductor is verified according to the second deformation characteristic value to determine whether it meets a preset standard, wherein,

[0040] If the second deformation characteristic value is less than the third preset deformation characteristic value, then it is determined that the coating of the dielectric body on the inner conductor meets the preset standard;

[0041] If the second deformation characteristic value is greater than or equal to the third preset deformation characteristic value, then reduce the traction speed;

[0042] The decrease in traction speed is positively correlated with the difference between the second deformation characteristic value and the third preset deformation characteristic value.

[0043] Further, in step S5,

[0044] If the equivalent dielectric constant is less than the preset equivalent dielectric constant, then the electromagnetic shielding performance is judged to meet the preset standard.

[0045] If the equivalent dielectric constant is greater than or equal to the preset equivalent dielectric constant, the electromagnetic shielding performance is determined to be non-compliant with the preset standard, and the wrapping gap is reduced.

[0046] Furthermore, the reduction in the wrapping gap is directly related to the difference between the equivalent dielectric constant and the preset equivalent dielectric constant.

[0047] Compared with the prior art, the beneficial effects of the present invention are that the fan-shaped through-hole structure can effectively reduce the total amount of dielectric material and reduce its influence on temperature changes, thereby stabilizing the phase delay of the signal; the through-hole structure is equivalent to reducing the overall dielectric constant of the insulation layer, which is beneficial to reducing signal transmission loss and achieving low attenuation; the reinforcing ribs and inner and outer support layers constitute a stable support frame, ensuring the structural strength and shape stability of the cable, while the through-hole design also gives the cable better flexibility, making wiring and installation easier.

[0048] Furthermore, limiting the ratio of the reinforcing rib thickness to the outer diameter of the dielectric material within a specific range is the optimal balance point between mechanical strength and dielectric material usage. If the ratio is too small, the strength will be insufficient; if it is too large, the dielectric material usage will increase, which is not conducive to low loss and phase stability. Fixing the number of fan-shaped through holes to 6 ensures the symmetry of the cable structure in all directions and the consistency of electrical performance, avoiding uneven performance caused by bending.

[0049] Furthermore, the outer shielding body is made of braided silver-plated copper wire, combined with the outer conductor, which has excellent shielding effect, effectively suppresses electromagnetic interference, and ensures signal amplitude stability.

[0050] Furthermore, silver-plated copper strips are used, taking advantage of silver's high conductivity to effectively reduce the transmission loss of high-frequency signals on the conductor; polytetrafluoroethylene and fluoroplastics are recognized high-temperature resistant materials, ensuring the structural stability and electrical reliability of the cable in high-temperature environments; the outer shielding body uses braided silver-plated copper wire, providing high-density electromagnetic shielding and effectively preventing signal interference and leakage.

[0051] Furthermore, online quality monitoring and data-driven real-time process adjustments were introduced, significantly reducing quality fluctuations in mass production and ensuring structural consistency. Bending tests and feedback adjustments in steps S3-S4 ensured uniform and tight dielectric coating, which is the physical basis for achieving stable electrical performance. Monitoring and adjusting the outer conductor wrapping gap in steps S5-S6 directly optimized the cable's impedance uniformity and shielding effectiveness, thereby reducing attenuation and reflection.

[0052] Furthermore, by defining specific experimental steps and calculating deformation characteristic values, the subjective judgment of coating quality is transformed into objective and quantifiable indicators, improving the accuracy of process control. A graded response mechanism is also established to trigger different levels of correction measures based on the degree to which the deformation characteristic value exceeds the threshold, making process control more intelligent and efficient. Among them, the first bending experiment mainly evaluates the structural anisotropy, while the second bending experiment verifies the structural uniformity. The traction speed affects the material plasticization, and the extrusion pressure directly affects the coating tightness. Adjustments are made to address the root causes of different problems, resulting in better effects.

[0053] Furthermore, using the equivalent dielectric constant as a criterion means that process control directly serves the final electrical performance target, ensuring the low-loss characteristics of the product; specifying that the reduction in the wrapping gap is positively correlated with the deviation of the equivalent dielectric constant makes process adjustment more precise and stable, avoids over-adjustment, and ensures the uniformity of product quality. Attached Figure Description

[0054] Figure 1 is a schematic diagram of the structure of a low-loss radio frequency coaxial cable with high temperature phase stability according to an embodiment of the present invention;

[0055] Figure 2 is a schematic diagram of the dielectric cross-section of the low-loss radio frequency coaxial cable with high temperature phase stability according to an embodiment of the present invention.

[0056] Figure 3 is a schematic flowchart of the method for preparing a low-loss radio frequency coaxial cable with high temperature phase stability according to an embodiment of the present invention.

[0057] Figure 4 is a logical diagram of steps S3 and S4 of the method for preparing a low-loss radio frequency coaxial cable with high temperature phase stability according to an embodiment of the present invention.

[0058] In the figure: 1. Inner conductor; 2. Dielectric; 3. Outer conductor; 4. Intermediate; 5. Outer shield; 6. Sheath; 201. Inner conductor wrapping layer; 202. Sector-shaped through hole. Detailed Implementation

[0059] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0060] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0061] Please refer to Figures 1 and 2, which are respectively a structural schematic diagram and a dielectric cross-section schematic diagram of the low-loss radio frequency coaxial cable with high temperature phase stability according to an embodiment of the present invention.

[0062] An embodiment of the present invention provides a low-loss radio frequency coaxial cable with high temperature phase stability, comprising: an inner conductor 1, a dielectric body 2, an outer conductor 3, an intermediate body 4, an outer shield 5, and a sheath 6;

[0063] Specifically, the cross-section of the dielectric body 2 is a core structure, which includes an inner conductor 1 wrapping layer and an outer conductor 3 support layer concentrically disposed outside the inner conductor 1 wrapping layer.

[0064] The inner conductor 1 sheathing layer and the outer conductor 3 support layer are provided with several reinforcing ribs at equal angles along the center; a fan-shaped through hole 202 is formed between the reinforcing ribs, the inner conductor 1 sheathing layer and the outer conductor 3 support layer.

[0065] Specifically, the ratio of the thickness of the reinforcing rib to the outer diameter of the medium body 2 ranges from 0.05 to 0.12;

[0066] The number of sector-shaped through holes is 6.

[0067] It is understandable that conventional PFA insulation layers have a solid core structure, while this invention adopts a core-coupled structure. Multiple through-holes extending along the cable axis are circumferentially and uniformly distributed on the cross-section of the dielectric layer. The number of through-holes is subject to strict requirements; too few through-holes will result in poor reduction of the equivalent dielectric constant and insignificant improvement in loss; too many through-holes will weaken the mechanical strength of the dielectric layer. Furthermore, the ratio of the minimum wall thickness between any two adjacent through-holes to the outer diameter of the core-coupled dielectric layer satisfies a value between 0.05 and 0.12. This design ensures that the hole walls are not prone to collapse when the core-coupled structure is subjected to lateral pressure or bending, thereby guaranteeing excellent mechanical properties.

[0068] Specifically, the inner conductor 1 includes a copper core conductor and a silver plating layer on the outside of the copper core conductor;

[0069] The outer conductor 3 is a silver-plated copper strip with a wrapping structure; this structure completely covers the surface of the dielectric 2, effectively increasing the shielding efficiency of the cable, reducing signal attenuation, and increasing the flexibility of the cable.

[0070] The intermediate body 4 is a polytetrafluoroethylene tape with a wrapping structure, which makes the cable structure more stable;

[0071] The outer shield 5 is a braided structure made of silver-plated copper wire, which can increase the cable's tensile strength, compressive strength and shielding performance.

[0072] The sheath 6 is made of fluoroplastic to ensure the cable's high-temperature resistance, enabling it to operate normally at temperatures up to 200°C.

[0073] Please refer to Figure 3, which is a schematic flowchart of the fabrication method of a low-loss radio frequency coaxial cable with high temperature phase stability according to an embodiment of the present invention, including:

[0074] Step S1: Soluble polytetrafluoroethylene is injected into an extruder, heated to a preset temperature, and then extruded into a pre-made extrusion mold; preferably, the preset temperature is 150°C.

[0075] The inner conductor 1 passes through the center of the extrusion mold;

[0076] Step S2: The medium 2 is coated on the inner conductor 1 at a preset traction speed and a preset extrusion pressure; preferably, the preset traction speed is 10 m / s and the preset extrusion pressure is 10 MPa.

[0077] Step S3: Perform a first bending test on several points on the inner conductor 1 after the coating is completed, and obtain the size information of the corresponding cross section at each point to obtain the first deformation characteristic value.

[0078] Step S4: If the coating of the dielectric body 2 on the inner conductor 1 does not meet the preset standard based on the first deformation characteristic value, the second bending test is used for verification, or the extrusion pressure is adjusted.

[0079] Step S5: Use silver-plated copper strip to wrap around the surface of the dielectric body 2 to form an outer conductor 3, and obtain the equivalent dielectric constant;

[0080] Step S6: If the electromagnetic shielding performance of the outer conductor 3 does not meet the preset standard based on the equivalent dielectric constant, adjust the wrapping gap.

[0081] Step S7: Wrap a polytetrafluoroethylene tape around the outer conductor 3 to form an intermediate body 4;

[0082] Step S8: Cover the outside of the intermediate body 4 with an outer shield 5 and a sheath 6.

[0083] Specifically, in step S3, the first bending experiment includes:

[0084] Step S31: Cut a 0.1m long sample, cool it to room temperature and place it flat for 1 hour to obtain the diameter of any end section;

[0085] Step S32: Bend the sample at several points along a specified direction by 90°, obtain the major axis length data of any end section, and repeat the experiment at several specified points.

[0086] Step S33: Determine the first deformation characteristic value based on the average value of the major axis length and the diameter length;

[0087] The first characteristic value is the ratio of the average length of the major axis to the length of the diameter.

[0088] In this embodiment, the first bending experiment is conducted at four points located at distances of 0.02m, 0.04m, 0.06m, and 0.08m from either end.

[0089] Please refer to Figure 4, which is a logical schematic diagram of steps S3 and S4 of the method for preparing a low-loss radio frequency coaxial cable with high temperature phase stability according to an embodiment of the present invention. Specifically, in response to the first deformation characteristic value being greater than or equal to a first preset deformation characteristic value and less than a second preset deformation characteristic value, and in response to the first deformation characteristic value being greater than or equal to the second preset deformation characteristic value, it is determined that the coating of the dielectric body on the inner conductor does not meet the preset standard; preferably, the first deformation characteristic value is 1.05 and the second deformation characteristic value is 1.1.

[0090] If the first deformation characteristic value is greater than or equal to the first preset deformation characteristic value and less than the second preset deformation characteristic value, then a second bending test is performed on the sample to obtain the second deformation characteristic value to verify whether the coating of the medium on the inner conductor meets the preset standard.

[0091] It is understood that in this embodiment, the first deformation characteristic value is greater than or equal to the first preset deformation characteristic value and less than the second preset deformation characteristic value, indicating that the first deformation characteristic value is in a slightly abnormal range. Although it exceeds the ideal range, it has not reached a very serious level. By introducing a more rigorous second bending test, a more accurate second deformation characteristic value is obtained, and adjustments are made according to the second deformation characteristic value to ensure the accuracy of the process parameters.

[0092] If the first deformation characteristic value is greater than or equal to the second preset deformation characteristic value, then the extrusion pressure is increased;

[0093] The increase in the extrusion pressure is positively correlated with the difference between the first deformation characteristic value and the second preset deformation characteristic value;

[0094] It is understood that in this embodiment, the positive correlation is not limited to linear or nonlinear positive correlation, and the slope of the linear positive correlation is also not limited. It can be set according to the actual preparation conditions. It is only necessary to satisfy that the greater the difference between the first deformation characteristic value and the second preset deformation characteristic value, the greater the increase in extrusion pressure. When the first deformation characteristic value is greater than or equal to the second preset deformation characteristic value, it indicates that the first deformation characteristic value is in a severely abnormal range. At this time, there is no need to spend time and cost to perform secondary verification, and corrective measures can be taken directly. By increasing the extrusion pressure, the density of the PFA melt is improved, so that the dielectric body is more tightly wrapped on the inner conductor, reducing the internal gaps, so as to form a denser and more firmly bonded dielectric layer, which is less likely to deform or loosen under the action of external forces such as bending.

[0095] Specifically, in step S4, the second bending experiment includes:

[0096] Step S41: Bend the sample at several points along a random direction by 90°, obtain the major axis length data of any end section, and repeat the experiment at several designated points.

[0097] Step S42: Determine the second deformation characteristic value based on the variance of the acquired major axis length data;

[0098] In this embodiment, the second bending experiment is conducted at four points located at distances of 0.02m, 0.04m, 0.06m, and 0.08m from either end.

[0099] Specifically, the coating of the dielectric body on the inner conductor is checked according to the second deformation characteristic value to see if it meets a preset standard, wherein...

[0100] If the second deformation characteristic value is less than the third preset deformation characteristic value, it is determined that the coating of the dielectric body 2 on the inner conductor 1 meets the preset standard. Preferably, the third preset deformation characteristic value is 0.05.

[0101] If the second deformation characteristic value is greater than or equal to the third preset deformation characteristic value, then reduce the traction speed;

[0102] The decrease in traction speed is positively correlated with the difference between the second deformation characteristic value and the third preset deformation characteristic value.

[0103] Understandably, in this embodiment, when an abnormality is found during the preparation process, the traction speed is immediately reduced. Since the traction speed is a key parameter that determines the molding and cooling time of the PFA melt on the inner conductor, if the traction speed is too fast, the PFA melt may stay in the mold for too short a time, which is not enough time to fully plasticize and distribute evenly. This results in uneven internal stress, poor bonding with the inner conductor, and rapid cooling and solidification of the surface layer while the inner layer cools slowly, generating internal stress. This can easily lead to deformation such as delamination and cracking when bending.

[0104] Specifically, in step S5, if the equivalent dielectric constant is less than the preset equivalent dielectric constant, then the electromagnetic shielding performance is determined to meet the preset standard.

[0105] If the equivalent dielectric constant is greater than or equal to the preset equivalent dielectric constant, it is determined that the electromagnetic shielding performance does not meet the preset standard, and the wrapping gap is reduced. Preferably, the preset equivalent dielectric constant is 1.6.

[0106] Specifically, the reduction in the wrapping gap is directly related to the difference between the equivalent dielectric constant and the preset equivalent dielectric constant.

[0107] It is understood that in this embodiment, the equivalent dielectric constant is a physical parameter that measures the material's ability to store electrical energy. At the outer conductor level of the cable, more attention should be paid to the macroscopic electromagnetic characteristics exhibited by the entire shielding structure, namely the equivalent dielectric constant. There is a direct negative correlation between the equivalent dielectric constant and the electromagnetic shielding performance: the lower the equivalent dielectric constant, the better the shielding performance; the higher the equivalent dielectric constant, the worse the shielding performance. Therefore, by detecting this key parameter of the equivalent dielectric constant, it is possible to inversely deduce whether the electromagnetic shielding effect of the cable meets the standard.

[0108] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0109] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for fabricating a low-loss radio frequency coaxial cable with high temperature phase stability, characterized in that, Includes the following steps: Step S1: Soluble polytetrafluoroethylene is injected into an extruder, heated to a preset temperature, and then extruded into a pre-made extrusion mold to form a dielectric body; wherein, the inner conductor passes through the center of the extrusion mold, and the inner conductor includes a copper core conductor and a silver-plated layer on the outside of the copper core conductor; Step S2: The dielectric body is coated on the inner conductor at a preset traction speed and a preset extrusion pressure; Step S3: A first bending test is performed on several points on the coated inner conductor to obtain the dimensional information of the corresponding cross-sections at each point to obtain a first deformation characteristic value; Step S4: Based on the first deformation characteristic value, the dielectric body is determined on the inner conductor... When the coating does not meet the preset standard, the coating condition of the medium is verified according to the second bending test to obtain the second deformation characteristic value, or the extrusion pressure is adjusted. If the second deformation characteristic value is less than the third preset deformation characteristic value, it is determined that the coating of the medium on the inner conductor meets the preset standard; if the second deformation characteristic value is greater than or equal to the third preset deformation characteristic value, the traction speed is reduced; the reduction in traction speed is positively correlated with the difference between the second deformation characteristic value and the third preset deformation characteristic value; in step S5, a silver-plated copper strip is used to wrap around the surface of the medium to form an outer conductor, and the results are obtained. Equivalent dielectric constant; Step S6, based on the equivalent dielectric constant, when determining whether the electromagnetic shielding performance of the outer conductor meets the preset standard, adjust the wrapping gap, wherein, if the equivalent dielectric constant is less than the preset equivalent dielectric constant, it is determined that the electromagnetic shielding performance meets the preset standard; if the equivalent dielectric constant is greater than or equal to the preset equivalent dielectric constant, it is determined that the electromagnetic shielding performance does not meet the preset standard, and the wrapping gap is reduced, the reduction of the wrapping gap being positively correlated with the difference between the equivalent dielectric constant and the preset equivalent dielectric constant; Step S7, wrap polytetrafluoroethylene tape around the outer conductor to form an intermediate body; Step S 8. An outer shield and a sheath are wrapped around the outside of the intermediate body. The outer shield is made of silver-plated copper wire with a braided structure, and the sheath is made of fluoroplastic. The cross-section of the dielectric body is a core structure. The core structure includes an inner conductor wrapping layer and an outer conductor support layer concentrically arranged outside the inner conductor wrapping layer. Several reinforcing ribs are arranged at equal angles along the center of the core on the inner conductor wrapping layer and the outer conductor support layer. Fan-shaped through holes are formed between the reinforcing ribs, the inner conductor wrapping layer, and the outer conductor support layer. The ratio of the thickness of the reinforcing ribs to the outer diameter of the dielectric body is in the range of 0.05-0.12, and the number of fan-shaped through holes is 6.

2. The method for fabricating a low-loss radio frequency coaxial cable with high temperature phase stability according to claim 1, characterized in that, In step S3, the first bending experiment includes: step S31, cutting a 0.1m long sample, cooling it to room temperature and placing it flat for 1 hour, and obtaining the diameter of any end section; step S32, bending the sample at several points along a specified direction by 90°, obtaining the major axis length data of any end section, and repeating the experiment at several specified points; step S33, determining the first deformation characteristic value based on the average value of the major axis length and the diameter length.

3. The method for fabricating a low-loss radio frequency coaxial cable with high temperature phase stability according to claim 2, characterized in that, In response to the first deformation characteristic value being greater than or equal to a first preset deformation characteristic value, it is determined that the coating of the dielectric body on the inner conductor does not meet the preset standard; wherein, if the first deformation characteristic value is greater than or equal to the first preset deformation characteristic value and less than a second preset deformation characteristic value, a second bending test is performed on the sample to obtain the second deformation characteristic value to verify whether the coating of the dielectric body on the inner conductor meets the preset standard; if the first deformation characteristic value is greater than or equal to the second preset deformation characteristic value, the extrusion pressure is increased; wherein, the increase in the extrusion pressure is positively correlated with the difference between the first deformation characteristic value and the second preset deformation characteristic value.

4. The method for fabricating a low-loss radio frequency coaxial cable with high temperature phase stability according to claim 3, characterized in that, In step S4, the second bending experiment includes: step S41, bending the sample at several points along a random direction by 90°, obtaining the major axis length data of any end section, and repeating the experiment at several designated points; step S42, determining the second deformation characteristic value based on the variance of the obtained major axis length data.

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