Radio frequency coaxial cable with temperature control function

Abstract

The application relates to the technical field of radio frequency coaxial cables, in particular to a radio frequency coaxial cable with a temperature control function, which comprises a cable main body, the cable main body comprises an inner conductor, an insulation layer, an outer conductor, a temperature control layer and a protective layer from inside to outside, the insulation layer comprises a first foaming layer and a second foaming layer; the first foaming layer and the second foaming layer both contain a first filler, and the addition ratio of the first filler is 5-10%; the foaming degree of the first foaming layer is higher than that of the second foaming layer; the temperature control layer contains organic fatty alkane; an outer skin layer is arranged between the temperature control layer and the outer surface of the outer conductor; and the thickness of the temperature control layer is 2-6 mm. Through the gradient design of the insulation layer, the heat conduction optimization of the outer skin layer and the synergistic effect of the active heat absorption of the temperature control layer, the working temperature of the cable is stabilized in a safe range under a high-temperature environment, so that the stability of signal transmission is guaranteed and the service life of the cable is prolonged.

Description

Technical Field

[0001] This application relates to the field of radio frequency coaxial cable technology, and in particular to a radio frequency coaxial cable with temperature control function. Background Technology

[0002] The electrical properties of conventional radio frequency (RF) cables (such as characteristic impedance and attenuation constant) fluctuate with changes in ambient temperature, affecting the stability and quality of signal transmission, especially outdoors or in environments with large temperature differences. During operation, conductor heating or high external temperatures can cause excessively high internal temperatures in RF cables, accelerating material aging, affecting insulation performance, and even posing safety hazards. Traditional cables lack intelligent temperature regulation capabilities; they can only passively withstand temperature changes and cannot actively adjust to maintain a relatively stable temperature range. Summary of the Invention

[0003] At least one aspect and advantage of this application will be set forth in part in the description which follows, or may be apparent from the description, or may be acquired by practicing the subject matter of this application.

[0004] According to the first aspect of this application, a radio frequency coaxial cable with temperature control function is provided, including a cable body, the cable body including an inner conductor, an insulation layer, an outer conductor, a temperature control layer and a protective layer from the inside to the outside, the insulation layer including a first foaming layer and a second foaming layer;

[0005] Both the first foam layer and the second foam layer contain a first filler, and the addition ratio of the first filler is 5-10%.

[0006] The degree of foaming of the first foam layer is higher than that of the second foam layer;

[0007] The temperature control layer contains organic fatty alkanes;

[0008] An outer skin layer is provided between the temperature control layer and the outer surface of the outer conductor;

[0009] The thickness of the temperature control layer is 2-6mm.

[0010] According to one embodiment of this application, the melting point of the fatty alkane is 50-80°C.

[0011] According to one embodiment of this application, the temperature control layer further comprises mesoporous silica.

[0012] According to one embodiment of this application, the matrix material of the temperature control layer is cross-linked low-density polyethylene or ethylene-vinyl acetate copolymer.

[0013] According to one embodiment of this application, the organic fatty alkane includes fatty alkanes having 26 to 40 carbon atoms.

[0014] According to one embodiment of this application, the temperature control layer further includes silicon dioxide particles, the silicon dioxide particles having a pore size greater than 10 nm and a particle size of 0.5-20 micrometers.

[0015] According to one embodiment of this application, the fatty alkane is loaded within silica particles.

[0016] According to one embodiment of this application, the outer skin layer further includes calcium carbonate or wollastonite.

[0017] According to one embodiment of this application, the temperature control layer is formed by extrusion.

[0018] According to one embodiment of this application, the preparation process of the temperature control layer includes:

[0019] Keep the feed temperature below the melting point of the organic fatty alkane and ensure that the melt temperature inside the extruder is higher than the extrusion temperature of the outer skin layer. Set the extrusion temperature to be consistent with the extrusion temperature of the outer skin layer.

[0020] This application utilizes the synergistic effect of insulation layer gradient design, outer sheath thermal conductivity optimization, and active heat absorption of the temperature control layer to stabilize the cable's operating temperature within a safe range under high-temperature conditions, thereby ensuring the stability of signal transmission and extending the cable's service life. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0022] Figure 1 This is a schematic diagram of the cross-sectional structure of a radio frequency coaxial cable with temperature control function provided in one embodiment of this application.

[0023] Reference numerals: 1-Inner conductor 1; 2-Insulation layer; 3-Outer conductor; 4-Temperature control layer; 5-Protective layer; 6-Outer sheath; 100-Coaxial cable. Detailed Implementation

[0024] The content of this application will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the content of this application, and are not intended to imply any limitation on the scope of this application.

[0025] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". These terms are primarily used to better describe this application and its embodiments and are not intended to limit the indicated components to having a particular orientation, or being constructed and operated in a particular orientation. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Furthermore, the terms "first", "second", etc., are primarily used to distinguish different components (the specific types may be the same or different) and are not intended to indicate or imply the relative importance and number of the indicated components. Unless otherwise stated, "a plurality of" means two or more.

[0026] According to one embodiment of this application, a radio frequency coaxial cable with temperature control function is provided, such as... Figure 1 As shown, the radio frequency coaxial cable 100 with temperature control function includes a cable body. The cable body includes, from the inside out, an inner conductor 1, an insulation layer 2, an outer conductor 3, a temperature control layer 4, and a protective layer 5. The insulation layer includes a first foaming layer and a second foaming layer. Both the first foaming layer and the second foaming layer contain a first filler, and the addition ratio of the first filler is 5-10%. The foaming degree of the first foaming layer is higher than that of the second foaming layer. The temperature control layer contains organic fatty alkane. An outer sheath layer 6 is provided between the outer surface of the temperature control layer 4 and the outer surface of the outer conductor 3. The thickness of the temperature control layer is 2-6 mm.

[0027] The high foaming degree of the inner layer in this application means a lower dielectric constant, which is beneficial for reducing signal attenuation, improving thermal insulation performance, optimizing impedance characteristics, and increasing flexibility while reducing weight. The gradient design of high foaming degree in the inner layer and low foaming degree in the outer layer allows the second foaming layer to maintain the temperature of the outer conductor side within a relatively stable range to a certain extent, and forms a temperature gradient to conduct heat from the inner conductor to the temperature control layer. The temperature of the outer conductor is regulated by using organic fatty alkanes.

[0028] Specifically, when the temperature of the temperature control layer rises to the melting point of the organic fatty alkane, the organic fatty alkane undergoes a phase change, absorbing a large amount of heat. Thus, even if the inner conductor continues to generate heat, this energy is used for the phase change of the organic fatty alkane, rather than further increasing the temperature. This keeps the temperature of the outer conductor below the melting point of the organic fatty alkane, avoiding the problem of low radiative heat dissipation efficiency of the outer sheath. For example, when n-hexadecane is used as the organic fatty alkane, since the melting point of n-hexadecane is approximately 60°C, the cable provided in this application maintains an outer conductor temperature below 60°C during operation.

[0029] Specifically, the thickness of the temperature control layer not only determines the cost and flexibility of the cable but also affects the temperature control effect. Experiments have shown that a thickness of less than 2mm results in insignificant temperature control, while a thickness greater than 6mm leads to an excessively large cable radius, increased cost, and decreased flexibility. A thickness of 2-6mm effectively controls the temperature while maintaining cable cost and flexibility. In practical applications, a temperature control layer thickness of 3-4mm is preferred. At this thickness, the temperature control layer does not excessively increase the cable's size and rigidity while ensuring sufficient capacity for organic fatty alkanes and high heat storage capacity.

[0030] In some embodiments, medium-density polyethylene or low-density polyethylene can be used for foaming when preparing the first foamed layer, wherein the filler addition ratio is set to 5-10%, which has the effect of obtaining a uniform and delicate high-foamed structure and stabilizing the reduction of dielectric constant. In practical applications, the filler addition ratio is preferably 7-8%, at which point the filler has the best effect on improving foaming or flame retardancy, and has the least impact on the dielectric properties and mechanical strength of the insulation layer.

[0031] In some embodiments, the first foam layer and the second foam layer are prepared in the following manner:

[0032] A foamed matrix (a mixture of low-density polyethylene and high-density polyethylene) and boron nitride (BN) were physically mixed and the resulting melt was then gas-foamed in an extruder and extruded onto a carrier. After irradiation crosslinking, the corresponding thermal conductivity was measured. For the unfilled foamed matrix, the thermal conductivity increased by 2-2.3% relative to the matrix. The BN filler used consisted of micro / nano materials of varying sizes. Although this increase in thermal conductivity appears relatively small, after fabricating a coaxial cable and operating it under a high load of 1.5 GHz, the outer sheath temperature of the unfilled cable stabilized at 80-90 degrees Celsius after half an hour using infrared measurements, while the outer sheath temperature of the filled cable was 78-87 degrees Celsius. This is because the increased thermal conductivity, to some extent, delays and transfers some of the accumulated heat, resulting in a slight decrease in operating temperature.

[0033] The thickness of the first foam layer and the second foam layer can be selected in the range of 1:0.5-1, and the performance is better when the proportion of the first foam layer is higher.

[0034] In this application, if polyethylene with fibers or clear orientation and BN fibers are used, the performance should be greatly improved, but the cost will increase significantly.

[0035] In addition, tests revealed that when only one type of filler was provided, the improvement in performance was limited. However, when different particle size ratios were provided, the actual performance improvement was higher than that of a single type. For example, when only 0.1-2 micrometer fillers were used, the increase in thermal conductivity was 0.7-0.8%. This is because BN particles with different particle size ratios and morphologies may form a three-dimensional spatial structure during foaming, thereby improving thermal conductivity to some extent.

[0036] Specifically, the protective layer has a barrier function, which can prevent organic fatty alkanes in the temperature control layer from migrating or penetrating into the outer conductor under long-term high temperature to form grease and affect its electrical performance.

[0037] Specifically, the protective layer typically uses polyethylene (PE) or polyvinyl chloride (PVC), polyurethane (PUR, abrasion-resistant and oil-resistant), LSZH (flame retardant and low smoke), etc., which will not be listed here.

[0038] Specifically, the inner conductor is typically made of a highly conductive metal such as copper or aluminum. Due to the skin effect, current flows on the surface of the conductor; therefore, the inner conductor can be made of commonly used copper wire or copper-clad aluminum wire. To reduce the weight of the cable, a copper tube can also be used as the inner conductor, thus reducing the cable's weight and cost while maintaining conductivity. The inner conductor serves as the carrier for signal transmission, and the signal current flows within it.

[0039] The fabrication process of an inner conductor can typically include:

[0040] The copper rod is drawn one through a wire drawing machine to achieve the designed radius; then it is annealed to obtain the inner conductor used to manufacture coaxial cables.

[0041] Specifically, the outer conductor typically employs a highly sealed structure (such as a metal tube) to prevent moisture, humidity, dust, and other environmental media from entering the cable, thus avoiding moisture-induced aging of the insulation layer and extending the cable's service life in outdoor and underground environments. In most cases, the outer conductor is covered with a sheath to isolate it from the external environment.

[0042] According to one embodiment of this application, the melting point of the organic fatty alkane is 50-80°C; this melting point range determines the selection range of the organic fatty alkane, and the temperature control layer can be prepared by selecting any organic fatty alkane with a melting point of 50-80°C. For example, n-hexadecane, which has 26 carbon atoms, has a melting point range of approximately 55-58°C.

[0043] According to one embodiment of this application, the temperature control layer further comprises mesoporous silica. Organic fatty alkanes change from a solid to a liquid state upon reaching their melting point. After this phase change, the liquid may seep out from the substrate, causing the temperature control function to fail and potentially contaminating other components (such as the external conductor). The pore walls of mesoporous silica can provide numerous nucleation sites for the crystallization of organic fatty alkanes. Using the porous structure of mesoporous silica can firmly lock the liquid organic fatty alkane within its nanopores. This solves the seepage problem caused by the phase change of organic fatty alkanes and allows them to solidify and release heat promptly at temperatures close to their theoretical melting point, ensuring the response speed and reliability of thermal management. In practical applications, mesoporous silica typically accounts for 10%-30% of the total mass, preferably 15%-25%, which solves the leakage problem without affecting processing.

[0044] Specifically, a temperature control layer containing mesoporous silica can be prepared using a vacuum impregnation method, as follows:

[0045] 1. Preparation of composite powder:

[0046] First, an organic fatty alkane (such as n-hexadecane) is heated above its melting point until it is completely melted into a liquid. Then, mesoporous silica powder is added to the molten n-hexadecane and stirred thoroughly to form a slurry. The mixture is then placed in a vacuum environment, and finally, heating is stopped, allowing the mixture to cool to room temperature. The n-hexadecane solidifies within the pores, yielding a dry composite powder.

[0047] 2. Preparation of the temperature control layer:

[0048] The composite powder is mixed evenly with the matrix material particles of the temperature control layer, antioxidants and other additives in a high-speed mixer; the mixed material is melt-blended, extruded, cooled and pelletized through a twin-screw extruder to obtain the temperature control layer masterbatch; the temperature control layer masterbatch is fed into an extruder, melted and extruded and coated onto the cable core with the existing outer sheath, and after cooling and cross-linking curing, the final temperature control layer is formed.

[0049] According to one embodiment of this application, the matrix material of the temperature control layer is cross-linked low-density polyethylene or ethylene-vinyl acetate copolymer.

[0050] According to one embodiment of this application, ethylene-vinyl acetate copolymer is used as the matrix material when preparing the temperature control layer. Ethylene-vinyl acetate copolymer has high compatibility with organic fatty alkanes. During preparation, the above-mentioned temperature control layer preparation process can be followed. The composite powder is directly mixed with ethylene-vinyl acetate copolymer particles (or powder), antioxidants and other additives in a high-speed mixer until uniform. The mixed material is melt-blended, extruded, cooled and pelletized through a twin-screw extruder to obtain temperature control layer masterbatch. The temperature control layer masterbatch is fed into an extruder, melted and extruded, and coated onto the cable core with the existing outer sheath. After cooling and cross-linking curing, the final temperature control layer is formed.

[0051] According to one embodiment of this application, cross-linked low-density polyethylene is used to prepare the temperature control layer. Since polyethylene has poor compatibility with organic fatty alkanes, the composite powder is directly mixed with ethylene-vinyl acetate copolymer particles (or powder), antioxidants, and other additives in a high-speed mixer until homogeneous. The mixed material is then melt-blended, extruded, cooled, and pelletized using a twin-screw extruder to obtain the temperature control layer masterbatch. The masterbatch is fed into an extruder, melted, extruded, and coated onto an outer conductor with an existing outer sheath. After cooling and shaping, it is finally subjected to electron irradiation to form polyethylene macromolecular free radicals that interconnect, forming a three-dimensional network structure that firmly confines the organic fatty alkanes and silica complex within this three-dimensional network structure.

[0052] According to one embodiment of this application, the organic fatty alkane includes fatty alkanes with 26 to 40 carbon atoms. When the melting point is 50-80°C, the selected organic fatty alkane is mainly aliphatic alkanes with 26 to 40 carbon atoms. The appropriate fatty alkane is selected during the preparation of the temperature control layer based on the temperature range of the cable's application scenario.

[0053] For example, when the temperature control environment requirement is 60°C, n-hexadecane with 26 carbon atoms (its melting point is about 60°C) can be selected; when the temperature control environment requirement is about 80°C, n-trichodecane with 36 carbon atoms (its melting point is about 80°C) can be selected.

[0054] According to one embodiment of this application, the temperature control layer further includes silica particles with a pore size greater than 10 nm and a particle size of 0.5-20 micrometers. Silica particles can adsorb organic fatty alkanes within their pores, but a pore size that is too small affects the loading rate of organic fatty alkanes into the pores and also affects their adsorption capacity. A pore size greater than 10 nm ensures effective protection against organic fatty alkanes and can effectively prevent phase change leakage. The pore size greater than 10 nm provides sufficient space for the organic fatty alkane molecules to arrange themselves in a lattice, allowing the organic fatty alkanes to be fixed inside the silica. The silica encapsulation allows for higher temperatures at the feed port during the temperature layer preparation process, reducing production process requirements. Simultaneously, it prevents leakage of organic fatty alkanes and extends the temperature control life of the cable.

[0055] Experiments have shown that the optimal pore size of silica particles is 20nm-50nm, which provides a large pore volume and a loading rate of 60%-80%, maximizing the heat capacity of the temperature control layer; the undercooling is reduced to below 5℃, and the undercooling effect is significant.

[0056] Experiments have shown that if the particle size is too small (<0.5μm), the particles are prone to agglomeration, forming clumps that are difficult to disperse; if the particle size is too large (>20μm), the particles are prone to sedimentation in the polymer melt, resulting in uneven distribution, and large particles can become stress concentration points, significantly reducing the flexibility and tensile strength of the composite material. Cables may crack at these points after repeated bending. Therefore, in this application, the particle size is set to 0.5-20μm. At this size, the composite powder of silica and organic fatty alkane has good flowability and can be uniformly mixed with the polymer matrix (such as cross-linked low-density polyethylene or ethylene-vinyl acetate copolymer) in the extruder like a common filler.

[0057] In some embodiments, the particle size is preferably 5μm-15μm, at which point the particles have good flowability, are not prone to agglomeration or sedimentation, and can be highly uniformly mixed with polymer particles by conventional mechanical stirring.

[0058] In this embodiment, silicon dioxide with a pore size of about 30 nm and a particle size of about 10 μm is used.

[0059] According to one embodiment of this application, the organic fatty alkane is loaded within silica particles.

[0060] In application, organic fatty alkanes can be loaded into silica particles using the following method: Solid fatty alkanes are dissolved in a volatile organic solvent (such as n-hexane, cyclohexane, or toluene), and then heated (for 2-3 hours) under nitrogen atmosphere to drive the organic fatty alkane molecules to diffuse deep into the pores and complete adsorption. A Buchner funnel or similar filtration device is used to rapidly filter the liquid using vacuum pressure. Vacuum treatment is then performed to remove residual solvent molecules. This method stably loads organic fatty alkanes into silica particles, laying a solid foundation for subsequent co-extrusion of composite powders with polymer matrices (such as EVA) to manufacture temperature-controlled layers.

[0061] According to one embodiment of this application, the outer skin layer further includes calcium carbonate or wollastonite.

[0062] The outer skin layer of this application embodiment has the function of preventing organic fatty alkane from permeating and leaking and affecting the outer conductor. The addition of calcium carbonate or wollastonite can improve the compressive strength, hardness and wear resistance of the outer skin layer.

[0063] In practical applications, the addition ratio of calcium carbonate or wollastonite can be set to 1%-2%; this ratio is limited to balance thermal conductivity, mechanical properties, and processing fluidity. This is because if the addition ratio is too small, an effective thermally conductive network cannot be formed, and its effect on improving thermal conductivity and enhancing the effect is negligible; if the addition ratio is too large, it will significantly increase the melt viscosity, leading to extrusion difficulties, surface roughness, melt fracture, and even failure to coat smoothly.

[0064] According to one embodiment of this application, the temperature control layer is formed by extrusion.

[0065] In some embodiments, any extrusion method can be used during preparation, such as directly feeding the composite powder of organic fatty alkane and silica, matrix material (such as ethylene-vinyl acetate copolymer) particles, and additives into an extruder, thereby heating, melting, mixing, and compressing the raw materials in the extruder. Through a specially designed die (die head), the raw materials are continuously and uniformly coated in a molten state onto the outer conductor or the outer skin layer of the outer conductor passing at a uniform speed. Finally, after cooling and shaping, a tubular temperature control layer with a dense structure, uniform thickness, and tight bonding with the lower layer is formed.

[0066] In some embodiments, during preparation, a composite powder of organic fatty alkane and silica can first be melt-blended with a matrix resin using a twin-screw extruder, granulated, and made into a temperature control layer masterbatch. Then, on a cable production line, the temperature control layer masterbatch is fed into a single-screw extruder for melt-extrusion coating. This method separates granulation and extrusion, ensuring uniform dispersion of the filler. Since the masterbatch is a homogeneous semi-finished product, the consistency of the final product can be guaranteed. This makes it easier to control, requiring only parameter control such as temperature during the extrusion process, thus improving the controllability of the temperature control layer and reducing the risk of organic fatty alkane degradation.

[0067] According to one embodiment of this application, the preparation process of the temperature control layer includes:

[0068] Keep the feed temperature below the melting point of the organic fatty alkane and ensure that the melt temperature inside the extruder is higher than the extrusion temperature of the outer skin layer. Set the extrusion temperature to be consistent with the extrusion temperature of the outer skin layer.

[0069] Specifically, feeding the organic fatty alkane at a temperature below its melting point prevents premature melting and adhesion, ensuring smooth feeding. In application, the feed port temperature is typically set to 40-50°C. When the organic fatty alkane is loaded within silica particles, even if the feed port temperature exceeds the melting point of the organic fatty alkane, such as to 60°C, the silica particles, acting as a protective shell, can maintain the organic fatty alkane in a solid state, preventing melting and adhesion.

[0070] Specifically, the melt temperature inside the extruder is higher than the extrusion temperature of the outer skin layer, and the extrusion temperature is the same as that of the outer skin layer. This ensures that the matrix material constituting the temperature control layer (such as cross-linked low-density polyethylene or ethylene-vinyl acetate copolymer) can be completely melted and fully plasticized, so that the filler of the temperature control layer is evenly dispersed in the polymer melt, and the temperature control layer and the outer skin layer are firmly bonded.

[0071] In one embodiment of the preparation process of a temperature-controlled layer, the preparation process is as follows: First, the temperature of the feed port is set to be less than 50°C, the barrel temperature to 120-160°C, and the die head temperature to 110-130°C; then, the temperature-controlled layer masterbatch is fed into the feed port and melted in the barrel; finally, it is extruded to the outer skin layer through the die head. After the temperature-controlled layer is extruded, it can be subjected to electron irradiation to form polyethylene macromolecular free radicals that connect with each other to form a three-dimensional network structure. This tightly confines the complex of organic fatty alkanes and silica within this three-dimensional network structure, greatly enhancing the shape stability and creep resistance of the temperature-controlled layer at high temperatures, and further preventing any potential leakage, especially in long-term use or extreme temperature scenarios.

[0072] The following are some specific embodiments to illustrate the preparation process of a radio frequency coaxial cable with temperature control function according to this application.

[0073] Example 1:

[0074] 1. Preparation of the first melt: The first filler and EVA resin are mixed evenly at a mass ratio of 1:3 and then foamed with medium-density polyethylene, so that the total addition ratio of the first filler is 5%, the foaming temperature is 180℃, the foaming pressure is 220 bar, the foaming gas is N2, and no nucleating agent is added.

[0075] 2. Preparation of the second melt: The second filler and EVA resin are mixed evenly at a mass ratio of 1:3 and then foamed with medium-density polyethylene, so that the total addition ratio of the second filler is 5%. The foaming temperature is 160℃, the foaming pressure is 200 bar, the foaming gas is N2, and no nucleating agent is added.

[0076] 3. Preparation of temperature control layer: A composite powder of organic fatty alkane and mesoporous silica powder is prepared, and then the composite powder is used to prepare temperature control layer masterbatch; then the temperature control layer masterbatch is fed into an extruder to obtain temperature control layer melt;

[0077] Then, a series extrusion process was used to first extrude 0.5 mm of high-density foamed polyethylene as the inner skin layer onto the inner conductor with a radius of 3 mm.

[0078] Then, the first foaming layer of 2mm is extruded onto the inner skin layer, and the extruder head temperature is 185℃;

[0079] Then, a second foam layer of 1.95 mm was extruded on the first foam layer, with the extruder head temperature at 160℃;

[0080] Then, the wrapped inner conductor is inserted into the outer conductor, and then the outer conductor is stretched to make them bonded.

[0081] Then an outer sheath is wrapped around the outer conductor;

[0082] Then, a 6mm temperature control layer melt is extruded onto the outer skin, and after cooling, the final temperature control layer is formed.

[0083] Then, a protective layer is wrapped around the outside of the protective layer to prepare a coaxial cable.

[0084] The cable was tested and found to have a characteristic impedance of 49.5 ohms. When transmitting a 1.5GHz signal, the attenuation was less than 0.25 dB / m. The temperature of the outer conductor was affected by factors such as dielectric loss and heat dissipation from the inner conductor. With existing cables, the outer conductor reached 60 degrees Celsius in 3 minutes; however, the cable of this application reached this temperature slightly later, with a delay of approximately 10 seconds. This demonstrates that the design of this application allows the cable to have certain high-temperature operating performance. Furthermore, actual measurements showed that under low load, the temperature of the outer sheath of the cable of this application decreased more slowly, meaning that the ambient temperature remained essentially stable.

[0085] Example 2:

[0086] 1. Preparation of the first melt: The first filler and EVA resin are mixed evenly at a mass ratio of 1:3 and then foamed with medium-density polyethylene, so that the total addition ratio of the first filler is 8%, the foaming temperature is 180℃, the foaming pressure is 220 bar, the foaming gas is N2, and no nucleating agent is added.

[0087] 2. Preparation of the second melt: The second filler includes the first filler, the second filler and EVA resin are mixed evenly at a mass ratio of 1:3 and then foamed with medium-density polyethylene, so that the total addition ratio of the second filler is 8%, the foaming temperature is 160℃, the foaming pressure is 200 bar, the foaming gas is N2, and no nucleating agent is added.

[0088] 3. Preparation of temperature control layer: A composite powder of organic fatty alkane and mesoporous silica powder is prepared, and then the composite powder is used to prepare temperature control layer masterbatch; then the temperature control layer masterbatch is fed into an extruder to obtain temperature control layer melt;

[0089] Then, a series extrusion process was used to extrude the first foam layer onto the inner conductor with a radius of 3 mm, with the extruder head temperature set at 180℃.

[0090] Then, a second foam layer is extruded on the first foam layer, with the extruder head temperature at 155℃.

[0091] Then, the wrapped inner conductor is inserted into the outer conductor, and then the outer conductor is stretched to make them bonded.

[0092] Then an outer sheath is wrapped around the outer conductor;

[0093] Then, a 6mm temperature control layer melt is extruded onto the outer skin, and after cooling, the final temperature control layer is formed.

[0094] Then, a protective layer is wrapped around the outside of the protective layer to prepare a coaxial cable.

[0095] The cable was tested and found to have a characteristic impedance of 49.7 ohms. When transmitting a 1.5GHz signal, the attenuation was less than 0.2 dB / m. The temperature of the outer conductor was affected by factors such as dielectric loss and heat dissipation from the inner conductor. With existing cables, the outer conductor reached 55 degrees Celsius in 3 minutes; however, the cable of this application reached this temperature slightly later, with a delay of approximately 9 seconds. This demonstrates that the design of this application allows the cable to have certain high-temperature operating performance. Furthermore, actual measurements showed that under low load, the temperature of the outer sheath of the cable of this application decreased more slowly, meaning that the ambient temperature remained essentially stable.

[0096] Example 3:

[0097] 1. Preparation of the first melt: The first filler and EVA resin are mixed evenly at a mass ratio of 1:3 and then foamed with medium-density polyethylene, so that the total addition ratio of the first filler is 10%, the foaming temperature is 180℃, the foaming pressure is 220 bar, the foaming gas is N2, and no nucleating agent is added.

[0098] 2. Preparation of the second melt: The second filler and EVA resin are mixed evenly at a mass ratio of 1:3 and then foamed with medium-density polyethylene, so that the total addition ratio of the second filler is 10%. The foaming temperature is 160℃, the foaming pressure is 200 bar, the foaming gas is N2, and no nucleating agent is added.

[0099] 3. Preparation of temperature control layer: A composite powder of organic fatty alkane and mesoporous silica powder is prepared, and then the composite powder is used to prepare temperature control layer masterbatch; then the temperature control layer masterbatch is fed into an extruder to obtain temperature control layer melt;

[0100] Then, a series extrusion process was used to first extrude 0.5 mm of high-density foamed polyethylene as the inner skin layer onto the inner conductor with a radius of 3 mm.

[0101] The first foam layer is then extruded onto the inner skin layer, with the extruder head temperature set at 180°C.

[0102] Then, a second foam layer is extruded on the first foam layer, with the extruder head temperature at 155℃.

[0103] Then, the wrapped inner conductor is inserted into the outer conductor, and then the outer conductor is stretched to make them bonded.

[0104] Then an outer sheath is wrapped around the outer conductor;

[0105] Then, a 6mm temperature control layer melt is extruded onto the outer skin, and after cooling, the final temperature control layer is formed.

[0106] Then, a protective layer is wrapped around the outside of the protective layer to prepare a coaxial cable.

[0107] The cable was tested and found to have a characteristic impedance of 49.7 ohms. When transmitting a 1.5GHz signal, the attenuation was less than 0.2 dB / m. The temperature of the outer conductor was affected by factors such as dielectric loss and heat dissipation from the inner conductor. With existing cables, the outer conductor reached 55 degrees Celsius in 3 minutes; however, the cable of this application reached this temperature slightly later, with a delay of approximately 12 seconds. This indicates that the design of this application allows the cable to have certain high-temperature operating performance. Furthermore, actual measurements showed that under low load, the temperature of the outer sheath of the cable of this application decreased more slowly, meaning that the operating environment temperature remained essentially stable.

[0108] In the above embodiments, low-density polyethylene (LDPE) is the lightest type of polyethylene resin, appearing as milky white, tasteless, odorless, non-toxic, and matte waxy granules. It possesses good flexibility, extensibility, electrical insulation, transparency, ease of processing, and a certain degree of air permeability. It exhibits good chemical stability, is resistant to alkalis and common organic solvents, and its density is generally 0.91-0.93 g / cm³. High-density polyethylene (HDPE) is a white powder or granular product. It is non-toxic, tasteless, has a crystallinity of 80%–90%, a softening point of 125–135℃, and a service temperature up to 100℃. Its hardness, tensile strength, and creep resistance are superior to LPE, and its density is generally 0.941-0.960 g / cm³. Medium-density polyethylene (MDPE) is a synthetic resin formed by copolymerizing ethylene with α-olefins (such as propylene and 1-butene), with a density range of 0.926-0.953 g / cm³.

[0109] In the above embodiments, EVA is used to improve foaming performance and enhance the flexibility and foaming properties of polyethylene. The amount added can be reduced or omitted as needed. When omitted, BN can be directly dispersed in the high-temperature melt of polyethylene.

[0110] During the above process, the parameters of the foaming process can be adjusted as needed to ensure that the degree of foaming meets the requirements.

[0111] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

[0112] It should be understood that the sequence number of each step in the invention and embodiments of this application does not absolutely imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The foregoing description of the implementation of this application has been given for illustrative and descriptive purposes. The foregoing description is not exhaustive and is not intended to limit this application to the exact form disclosed. Various modifications and variations may exist based on the above teachings, or various modifications and variations may be derived from the practice of this application. These embodiments were chosen and described to illustrate the principles of this application and its practical application, so that those skilled in the art can utilize this application in various implementations and modifications to suit the specific purpose of the concept. Those skilled in the art will understand that the above-described embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this application.

Claims

1. A radio frequency coaxial cable with temperature control function, characterized in that, The cable body includes, from the inside out, an inner conductor, an insulation layer, an outer conductor, a temperature control layer, and a protective layer. The insulation layer includes a first foaming layer and a second foaming layer. Both the first foam layer and the second foam layer contain a first filler, and the addition ratio of the first filler is 5-10%. The degree of foaming of the first foam layer is higher than that of the second foam layer; The temperature control layer contains organic fatty alkanes; An outer skin layer is provided between the temperature control layer and the outer surface of the outer conductor; The thickness of the temperature control layer is 2-6mm.

2. The radio frequency coaxial cable with temperature control function as described in claim 1, characterized in that, The melting point of the organic fatty alkane is 50-80℃.

3. The radio frequency coaxial cable with temperature control function as described in claim 2, characterized in that, The temperature control layer also contains mesoporous silica.

4. The radio frequency coaxial cable with temperature control function as described in claim 2, characterized in that, The base material of the temperature control layer is cross-linked low-density polyethylene or ethylene-vinyl acetate copolymer.

5. A radio frequency coaxial cable with temperature control function as described in claim 2, characterized in that, The organic fatty alkanes include fatty alkanes with 26 to 40 carbon atoms.

6. The radio frequency coaxial cable with temperature control function as described in claim 1, characterized in that, The temperature control layer also includes silicon dioxide particles, the pore size of which is greater than 10 nm and the particle size is 0.5-20 micrometers.

7. The radio frequency coaxial cable with temperature control function as described in claim 6, characterized in that, The organic fatty alkane is loaded within silica particles.

8. The radio frequency coaxial cable with temperature control function as described in claim 1, characterized in that, The outer skin layer also includes calcium carbonate or wollastonite.

9. A radio frequency coaxial cable with temperature control function as described in claim 1, characterized in that, The temperature control layer is formed by extrusion.

10. A radio frequency coaxial cable with temperature control function as described in claim 9, characterized in that, The preparation process of the temperature control layer includes: Keep the feed temperature below the melting point of the organic fatty alkane and ensure that the melt temperature inside the extruder is higher than the extrusion temperature of the outer skin layer. Set the extrusion temperature to be consistent with the extrusion temperature of the outer skin layer.

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