A low-loss high-power radio frequency coaxial cable and a leaky coaxial cable

Abstract

This application belongs to the field of wireless communication technologies. More specifically, it relates to a low-loss high-power radio frequency coaxial cable and a leaky coaxial cable. The radio frequency coaxial cable includes an inner conductor, an insulating layer, an outer conductor layer, and an outer sheath layer from the inside out. By optimizing the insulating layer and conductor structure, the overall thermal resistivity of the cable is improved, thereby enhancing the attenuation performance of the cable and the heat resistance performance in high-power application scenarios. Compared with high-power cables with a conventional structure, under the premise of meeting the temperature resistance level of 125 °C, the attenuation test value of the radio frequency coaxial cable with a 3 / 8-inch specification is optimized by approximately 15% compared to the requirements; under the premise of meeting the temperature resistance level of 105 °C, the attenuation test value of the leaky coaxial cable with a 1 / 2-inch specification is optimized by approximately 17% compared to the standard requirements.

Description

Technical Field

[0001] This application belongs to the field of wireless communication technologies, and more specifically, relates to a low-loss high-power radio frequency coaxial cable and a leaky coaxial cable. Background Art

[0002] With the rapid development of communication technologies, high-power communication devices have increasingly high requirements for the performance of coaxial cables. However, existing coaxial cables have some problems in high-power scenarios. First, due to the skin effect of the current inside the coaxial cable and the relatively small size of the inner conductor compared to the outer conductor, the current density of the inner conductor is large, resulting in relatively serious heat generation. In some cases, the operating temperature of the inner conductor can reach over 100°C. Second, although irradiating cross-linked polyethylene insulation to make cross-linked polyethylene insulation can increase the operating temperature to over 125°C, compared with the polyethylene insulation layer before cross-linking, the attenuation performance of the cross-linked polyethylene insulation layer deteriorates by at least more than 10%. For radio frequency coaxial cables and leaky coaxial cables used for communication, the attenuation in the main operating frequency band deteriorates by at least 3 dB, which means that the device power needs to be doubled to ensure the original signal strength. However, higher power will lead to more serious heat generation, further testing the temperature resistance performance of the cable. Finally, currently, the general operating frequency of conventional radio frequency coaxial cables is within the frequency band of 75 - 5000 MHz. For application scenarios with relatively high and wide frequencies, the inner conductor of the cable is generally copper wire, copper tube, or silver-plated on the copper layer to further reduce attenuation and improve temperature resistance performance. However, the electrical conductivity of other common metals with good temperature resistance is far inferior to that of silver-plated copper, and the attenuation performance far cannot meet the actual requirements.

[0003] Generally speaking, the operating power of the cable is jointly affected by the attenuation performance, heat dissipation performance, and temperature resistance performance of the materials. The existing coaxial cable structure can no longer meet the application scenarios with higher power, and there is an urgent need for structural optimization and material improvement to enhance its comprehensive performance and meet the requirements of high-power communication devices. Summary of the Invention

[0004] Aiming at the defects of the existing technology, the purpose of this application is to provide a low-loss high-power radio frequency coaxial cable and a leaky coaxial cable, aiming to solve the problem that the material attenuation performance, heat dissipation performance, and temperature resistance performance of the existing coaxial cable do not meet the usage requirements in high-power application scenarios.

[0005] To achieve the above object, the present application provides a low-loss high-power radio frequency coaxial cable. The radio frequency coaxial cable includes an inner conductor, an insulating layer, an outer conductor layer, and an outer sheath layer from the inside out. The insulating layer includes a polytetrafluoroethylene layer and a cross-linked polyethylene foamed layer. The polytetrafluoroethylene layer is formed by stranding and wrapping multiple polytetrafluoroethylene hollow ropes. The cross-linked polyethylene foamed layer is made by extruding polyethylene foam and then performing irradiation cross-linking with a preset irradiation dose. The outer conductor layer is a tubular structure formed by longitudinally wrapping a smooth copper strip, and the outer surface of the tubular structure is provided with corrugated lines formed by rolling.

[0006] Further, the inner diameter of the polytetrafluoroethylene hollow rope is 50% - 60% of its outer diameter.

[0007] Further, the thickness of the polytetrafluoroethylene layer is of the thickness of the insulating layer, and the thickness of the polytetrafluoroethylene layer is equal to the outer diameter of a single polytetrafluoroethylene rope.

[0008] Further, the preset irradiation dose is 8mrad - 30mrad.

[0009] Further, the opposite ends of the smooth copper strip are overlapped and fixed as a straight overlapping edge, and the width of the overlapping edge is 9% - 15% of the unfolded width of the copper strip.

[0010] Even further, the thickness of the smooth copper strip is 0.06mm - 0.15mm.

[0011] Further, a first adhesive layer is coated between the outer conductor layer and the insulating layer.

[0012] Further, a second adhesive layer is coated between the outer conductor layer and the outer sheath layer.

[0013] According to another aspect of the present application, there is also provided a low-loss high-power leaky coaxial cable. The leaky coaxial cable includes the structure of the radio frequency coaxial cable as described above, and slot holes or slits arranged in a periodic array are formed on its outer conductor layer.

[0014] Generally speaking, compared with the prior art by the above technical solution conceived by the present application, the following beneficial effects are obtained:

[0015] (1)The RF coaxial cable structure designed in this application wraps a layer of polytetrafluoroethylene layer around the inner conductor with a polytetrafluoroethylene hollow rope in a stranded manner, and then extrudes and forms a cross-linked polyethylene foam layer with a specific thickness outside the polytetrafluoroethylene hollow rope. The polytetrafluoroethylene layer and the cross-linked polyethylene foam layer form an integral insulation layer. This multi-layer insulation structure effectively prevents heat from conducting from the inner conductor to the outside, enabling the cable to maintain good insulation performance even when operating at a high power and generating a high temperature, thus enhancing the overall heat resistance of the cable. Moreover, the cross-linked polyethylene foam layer has a good cell structure, and the polytetrafluoroethylene hollow rope has air in the middle. This structure can reduce the dielectric constant of the insulation layer to a certain extent. When the polyethylene layer is made into cross-linked polyethylene after low irradiance and forms an integral insulation layer with the polytetrafluoroethylene hollow layer, the two cooperate with each other to optimize the transmission ability of the insulation layer for RF signals, reducing the attenuation of signals in the insulation layer compared with a single-layer cross-linked polyethylene or polytetrafluoroethylene insulation structure, thereby improving the attenuation performance of the cable.

[0016] (2)The outer conductor layer of the RF coaxial cable structure designed in this application is formed by longitudinally wrapping a smooth metal strip, making the outer conductor layer fit tightly with the insulation layer, exhausting air (air has strong heat insulation ability), enabling the heat flow temperature of the outer insulation layer to be transferred to the outside more quickly, reducing the temperature of the cross-linked polyethylene insulation layer, and the temperature of each layer of the cable gradually decreases from the inside to the outside, avoiding accumulation on the inner conductor, further improving the overall heat dissipation ability of the cable, further enhancing the heat dissipation ability of the cable and improving the attenuation performance of the cable. By forming shallow rolling marks after longitudinal wrapping to form the outer conductor corrugation pattern, the flexibility and heat dissipation area of the cable are increased, while the corrugation pattern formed by traditional welding rolling has air sandwiched between the corrugation and the insulation layer, which affects the heat dissipation ability of the insulation layer to a certain extent. In addition, since the outer conductor layer structure of this application has very shallow wrinkles on the outside and tends to be flat, the outer conductor copper strip has no shrinkage and a smaller resistance, which is beneficial to reducing the attenuation of the cable.

[0017] (3)In this application, the thickness of the polytetrafluoroethylene layer is designed to be 1 / 4 - 1 / 2 of the thickness of the entire insulation layer, and the used polytetrafluoroethylene rope is a hollow rope body. The inner diameter of the polytetrafluoroethylene hollow rope is 50% - 60% of its outer diameter, and the air volume ratio of the hollow rope body has a specific proportional relationship with the inner diameter of the hollow rope body, the outer diameter of the polytetrafluoroethylene layer, and the inner diameter of the polytetrafluoroethylene layer, so as to effectively reduce the dielectric constant. At the same time, the heat insulation performance of the hollow structure of the hollow rope body is stronger than that of the solid structure, enabling the inner layer of the polytetrafluoroethylene layer to withstand a higher temperature while the outer layer temperature is relatively lower, that is, the temperature level of the outer cross-linked polyethylene foam layer is relatively lower than that of the inner polytetrafluoroethylene layer.

[0018] (4) When there are no periodic slots or gaps on the outer conductor layer in this application, a radio frequency coaxial cable is formed. When periodic slots or gaps are designed on the outer conductor layer, a leaky coaxial cable is formed, corresponding to different application scenarios respectively, and the application range is wider. Description of the Drawings

[0019] Figure 1 is a schematic cross-sectional structure diagram of the cable provided by the embodiment of the present application;

[0020] Figure 2 is a schematic cross-sectional structure diagram of the polytetrafluoroethylene hollow rope provided by the embodiment of the present application.

[0021] In all the drawings, the same reference numerals are used to represent the same elements or structures, where:

[0022] 1 - inner conductor; 2 - outer conductor layer; 3 - outer sheath layer, 4 - polytetrafluoroethylene layer, 41 - hollow structure, 42 - polytetrafluoroethylene rope, 5 - crosslinked polyethylene foam layer. Specific Embodiments

[0023] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0024] The term "and / or" in this article is a relationship description of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The symbol " / " in this article represents an "or" relationship between associated objects, for example, A / B represents A or B.

[0025] The terms "first" and "second" in the specification and claims of this article are used to distinguish different objects, rather than to describe a specific order of the objects. For example, the first response message and the second response message are used to distinguish different response messages, rather than to describe the specific order of the response messages.

[0026] In the embodiments of the present application, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application should not be construed as being more preferred or more advantageous than other embodiments or design solutions. Exactly speaking, using words such as "exemplary" or "for example" aims to present relevant concepts in a specific way.

[0027] In the description of the embodiments of the present application, unless otherwise specified, "a plurality of" means two or more. For example, a plurality of processing units means two or more processing units, etc.; a plurality of elements means two or more elements, etc.

[0028] The embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

[0029] This embodiment provides a low-loss high-power radio frequency coaxial cable (hereinafter referred to as the cable), as Figure 1 and Figure 2 shown. The cable includes an inner conductor 1, an insulating layer, an outer conductor layer 2, and an outer sheath layer 3 from the inside out. The insulating layer includes a polytetrafluoroethylene layer 4 and a crosslinked polyethylene foamed layer 5. The polytetrafluoroethylene layer 4 is formed by stranding and wrapping multiple polytetrafluoroethylene hollow ropes. The crosslinked polyethylene foamed layer 5 is made by irradiating and crosslinking polyethylene foam after extrusion molding with a preset irradiation dose. The outer conductor layer 2 is a tubular structure formed by longitudinally wrapping a smooth copper strip, and the outer surface of the tubular structure (i.e., the surface away from the insulating layer) is provided with relatively shallow wrinkle patterns formed by rolling, and these wrinkle patterns can be arranged in a periodic array.

[0030] Specifically, the aforementioned inner conductor 1 is a solid silver-plated copper wire or a hollow copper tube. Using a silver-plated copper wire as the inner conductor 1 can further reduce the high-frequency skin effect loss and is used for high-end microwave transmission. Using a hollow copper tube as the inner conductor 1 has good electrical conductivity and can reduce the weight of the cable. The diameter of the inner conductor 1 needs to match the operating frequency. Due to the skin effect of high-frequency signals, the current is concentrated on the surface of the conductor. If the inner conductor 1 is too thick, the cost will increase. In addition, the inner conductor 1, together with the dimensions of the insulating layer and the outer conductor, determines the characteristic impedance of the cable.

[0031] The hollow structure 41 inside the polytetrafluoroethylene hollow rope 42 can reduce the equivalent dielectric constant of the material, reduce the loss of signal transmission, and at the same time reduce the weight. On the other hand, the air volume ratio of the polytetrafluoroethylene hollow rope 42 may affect the mechanical strength and heat conduction. For example, the hollow polytetrafluoroethylene rope may reduce the use of the actual polytetrafluoroethylene material (PTFE), but the thermal conductivity of air is poor, so the hollow structure 41 will increase the overall thermal resistance of the insulating layer, resulting in a larger temperature difference. Generally, the dielectric constant of microporous polytetrafluoroethylene material is about 1.5, and its temperature resistance grade is above 200 °C. Using a hollow structure can greatly reduce the dielectric constant of the overall polytetrafluoroethylene hollow rope 42. According to the dielectric constant formula of the double-layer combined insulation structure (i.e., the simplified formula when one layer is an air layer):

[0032] (1)

[0033] where x is the ratio of the volume of the solid medium to the total volume of the structure. When xWhen reaching 75%, for the microporous polytetrafluoroethylene medium Taking 1.53, the dielectric constant of the hollow rope can be reduced to 1.4.

[0034] For example, in the cable, the diameter of the inner conductor 1 is 3.6 mm, the total outer diameter of the insulation layer (i.e., the outer diameter of the cross-linked polyethylene foamed layer) is 11.8 mm, the thickness of the insulation layer is 4.1 mm, and the outer diameter of the polytetrafluoroethylene hollow rope that constitutes the polytetrafluoroethylene layer 4 in the insulation layer is 2.73 mm. When some high-power equipment operates at peak power for a long time, the power transmission value of the aforementioned cable can reach about 20 Kw or more, and the temperature difference between the inside and outside of the polytetrafluoroethylene layer 4 is about 10 degrees. Coupled with the heat dissipation of the outer layer of the cable, the actual temperature difference is nearly 20 degrees.

[0035] To solve the above problems, in the aforementioned insulation layer, the inner diameter size of the polytetrafluoroethylene hollow rope that constitutes the polytetrafluoroethylene layer 4 is designed to be 50% - 60% of its outer diameter size, such as 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59% or 60% of its outer diameter size, or any value between any two of the above ratio values.

[0036] The thickness of the aforementioned polytetrafluoroethylene layer 4 is also designed to be of the thickness of the entire insulation layer, and the thickness of the polytetrafluoroethylene layer 4 is made equal to the outer diameter of a single polytetrafluoroethylene rope (hereinafter referred to as a single rope). For example, the thickness of the insulation layer is designed to be 4.1 mm, the outer diameter of a single polytetrafluoroethylene hollow rope in the polytetrafluoroethylene layer is 1 / 4 of the thickness of the insulation layer, that is, 1.025 mm, and the diameter of its internal hollow area (i.e., the inner diameter of the polytetrafluoroethylene hollow rope) is 0.41 - 0.61 mm, and the hollowness ratio is about 25% - 36%. A single polytetrafluoroethylene hollow rope is formed by extrusion and stretching processes using PTFE dispersion resin, and then about 11 hollow single ropes are helically stranded around the inner conductor 1 at a winding angle of about 55° to form a single-layer honeycomb air-gap structure (the porosity can reach more than 40% at most); according to the calculation formula of the dielectric constant of the double-layer combined insulation layer:

[0037] (2)

[0038] Where d is the diameter of the inner conductor, D 1 is the outer diameter of the polytetrafluoroethylene layer, D 2 is the outer diameter of the cross-linked polyethylene foamed layer, is the dielectric constant of the polytetrafluoroethylene layer (i.e., the hollow rope), is the dielectric constant of the cross-linked polyethylene foam layer; according to the dimensions of this embodiment, the hollow ratio is taken as 25%, the dielectric constant of the microporous polytetrafluoroethylene rope medium is taken as 1.53, and the dielectric constant of the entire insulating layer can be reduced to about 1.39. For the microporous polytetrafluoroethylene insulating layer of general high-power cables, the optimal dielectric constant can reach below 1.5, and for the foamed cross-linked polyethylene foam layer of high-power cables meeting 125°C, the optimal dielectric constant can reach below 1.40; on the basis of the above examples, when the hollow ratio value of the polytetrafluoroethylene rope and the selection of the material dielectric constant are relatively optimal, the dielectric constant of the cable insulating layer can be further reduced.

[0039] The foregoing cross-linked polyethylene foam layer 5 is extrusion molded. Specifically, a PE base material (i.e., polyethylene) is premixed with a physical foaming agent (such as nitrogen, carbon dioxide foaming agent, nucleating agent). The foaming degree of the foam layer structure is required to be greater than 70% to meet the requirements of high-frequency and low loss, and the pore diameter is uniform and between 20μm and 50μm. After extrusion, it is gradually cooled and formed. Specifically, first, air cooling is used to gradually reduce its surface temperature, and then a water cooling tank is used for segmented temperature control to eliminate internal stress.

[0040] The foregoing outer conductor layer 2 specifically uses multiple sets of conical molds and guide wheels to gradually curl a flat and smooth copper strip into a closed cylinder (i.e., a tubular structure). The opposite ends of the cylinder overlap and are fixed as a linear overlap edge, and the width of the overlap edge is 9% - 15% of the unfolded width of the smooth copper strip, such as 9%, 10%, 11%, 12%, 13%, 14% or 15%, or any value between the above two values. If the overlap edge is too wide, it will cause an increase in the diameter of the outer conductor layer, reducing the tensile strength and bending performance of the cable. And because there is more material in the overlap edge part, it affects the flexibility and installation convenience of the cable, and the cable is more likely to deform or be damaged when subjected to external forces. If the overlap edge is too narrow, it will result in poor shielding effect of the outer conductor layer. In addition, if the overlap edge is too narrow, it will also cause instability during the curling and fixing process of the copper strip, prone to loosening or misalignment, affecting the quality and consistency of the cable, and thus affecting the electrical performance of the cable. In addition, a constant pressure (10MPa - 30MPa) is applied through a high-temperature pressure roller (heated to about 80°C) to make the glue layer evenly coated, and the grooved copper strip is tightly coated on the insulating layer through a sizing and binding device.

[0041] Compared with the outer conductor formed by the traditional corrugated copper tape wrapping and the braided outer conductor (such as silver-plated copper wire), the outer conductor layer 2 formed by the longitudinal wrapping of the smooth copper tape has a smaller conductor attenuation, which can further optimize the attenuation performance of the cable. In addition, the thermal resistivity of polyethylene is generally 350-450 thermal ohm-cm, the thermal resistivity of polytetrafluoroethylene is 500 thermal ohm-cm, and the thermal resistivity of still air is 4100 thermal ohm-cm. Therefore, reducing the air layer in the cable structure can improve the overall thermal resistivity of the cable and optimize the heat dissipation capacity. In this embodiment, the outer conductor layer 2 is formed by longitudinal wrapping of a smooth copper tape structure. Compared with the outer conductor layer 2 formed by wrapping with a corrugated copper tape, the formation of a hollow air layer between the insulating layer and the outer conductor layer can be avoided, thereby improving the heat dissipation capacity of the entire cable. The air in the hollow structure of the polytetrafluoroethylene hollow rope in the polytetrafluoroethylene layer can slow down the rapid dissipation of heat generated in the high-power cable to the cross-linked polyethylene foam layer 5, so that the temperature of the cross-linked polyethylene foam layer 5 can be reduced by about 20°C.

[0042] The thickness of the aforementioned copper strip is 0.06mm~0.15mm, such as 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.10mm, 0.11mm, 0.126mm, 0.13mm, 0.14mm or 0.15mm. The thin copper strip of this thickness can maximize the stability of high-frequency signal transmission. Too thin will lead to large resistance or easy breakage, and too thick will affect the bending performance of the cable and be inconvenient for installation and wiring. Furthermore, shallow corrugation after longitudinal wrapping can form shallower lines on the smooth copper strip, which can increase the bending performance and heat dissipation area of ​​the outer conductor layer of the cable without changing the amount of copper strip and the overall structural dimensions of the cable.

[0043] After the cross-linked polyethylene foam layer 5 is extruded and molded, the semi-finished product is first subjected to radiation cross-linking with a preset radiation amount. Specifically, the preset radiation amount is 8mrad~30mrad, such as the preset radiation amount is 8mrad, 9mrad, 10mrad, 11mrad, 12mrad, 13mrad, 14mrad, 15mrad, 16mrad, 17mrad, 18mrad, 19mrad, 20mrad, 21mrad, 22mrad, 23mrad, 24mrad, 25mrad, 26mrad, 27mrad, 28mrad, 29mrad or 30mrad, or any value between any two of the above values.

[0044] Compared with the structure where the insulating layer is pure polytetrafluoroethylene or highly irradiated cross-linked polyethylene, the cross-linked polyethylene with low irradiation dose has a lower temperature resistance level. Because at low irradiation doses, the degree of cross-linking of the molecular chains in cross-linked polyethylene (XLPE) is relatively low, and the insufficient degree of cross-linking makes the material prone to softening or deformation at high temperatures, thus reducing its heat resistance performance. However, the coaxial cable structures obtained under the cross-linked polyethylene foam layer with low irradiation dose all have better attenuation performance. Because an appropriate degree of cross-linking can optimize the dielectric properties of the material, and a lower degree of cross-linking can reduce the internal defects and stress concentration of the material, thereby reducing the attenuation of the signal during transmission. However, if the irradiation dose is too high (higher than 30 Mrad), the attenuation performance will drop significantly, or if the irradiation dose is too low (lower than 8 Mrad), the temperature resistance performance of the cable structure will not meet the application requirements.

[0045] Table 1 below shows the change in attenuation values of a cable of a certain specification provided by the embodiments of the present application after being irradiated with different irradiation doses in the same experimental environment. It can be seen from Table 1 below that at the same frequency, the cable attenuation degree corresponding to an irradiation dose of 10 Mrad is the smallest. As the irradiation dose gradually increases, the degree of cable attenuation deterioration increases significantly. Therefore, the coaxial cable structure obtained under the cross-linked polyethylene foam layer with low irradiation dose has better attenuation performance.

[0046] Table 1 Change in attenuation values of a cable of a certain specification under different irradiation doses

[0047]

[0048] The polytetrafluoroethylene layer 4 of the inner insulating layer has a relatively high temperature resistance level, up to above 200 °C. The cross-linked polyethylene foam layer 5 located outside the insulating layer does not need to reach the temperature resistance level of the polytetrafluoroethylene layer 4 inside the insulating layer. For example, when the working temperature is 125 °C, the outer cross-linked polyethylene layer only needs to meet the level of 105 °C. And the inner polytetrafluoroethylene layer 4 can isolate the relatively high temperature directly brought by the inner conductor 1. When the temperature is conducted to the cross-linked polyethylene layer, it is basically only about 105 °C (that is, the temperature gradually decreases from the inside to the outside). Therefore, the overall temperature resistance performance of the cable is stronger.

[0049] In this embodiment, a first adhesive layer is coated between the outer conductor layer 2 and the insulating layer to achieve their firm connection. Specifically, a thin layer of high-temperature resistant strong adhesive can be coated to closely paste the outer conductor layer 2 and the insulating layer. The thickness of the adhesive layer can be between 0.02 mm and 0.1 mm.

[0050] In the preferred embodiment, a second adhesive layer is coated between the aforementioned outer conductor layer 2 and the outer sheath layer 3 to achieve their firm connection. The thickness of the adhesive layer can be between 0.02 mm and 0.1 mm. The aforementioned outer sheath layer 3 is generally extruded and formed using materials such as polyethylene or polyvinyl chloride, and after forming, it is cooled and solidified at the same cooling speed as the extrusion speed to ensure the uniformity and quality of the outer sheath layer.

[0051] In another embodiment, based on the structure of the RF coaxial cable provided in the foregoing embodiment, periodic slots or slits are formed in the outer conductor layer 2 to form a leaky coaxial cable. This leaky coaxial cable allows part of the energy of the electromagnetic wave to leak out of the cable and radiate into the surrounding environment. At the same time, it also allows external electromagnetic waves to enter the cable through the slots. The foregoing slots or slits are arranged in an array around the central axis of the coaxial cable on the outer conductor layer 2. The shape of the slots can be in the shape of an inverted V, U, L, ellipse, etc., which are conventional slot shapes in the art. The size of the foregoing slits can be designed according to the actual application scenario and will not be elaborated here.

[0052] In summary, through the specific design of the structures of each layer of the coaxial cable in this application, the overall thermal resistivity of the cable is improved, thereby enhancing the attenuation performance of the cable and the heat resistance performance in high-power application scenarios. Compared with the high-power cable with a conventional structure, the low-loss high-power coaxial cable in this application optimizes the attenuation test value on the premise of meeting the temperature resistance level of 125°C. For example, the attenuation test value of the 3 / 8-inch specification of the RF coaxial cable at 2700 MHz can reach 21.4 dB / 100 m, which is optimized by about 15% compared with the standard requirements; on the premise of meeting the temperature resistance level of 105°C, the attenuation test value of the 1 / 2-inch specification of the leaky coaxial cable at 2700 MHz is about 14.5 dB / 100 m, which is optimized by about 17% compared with the standard requirements.

[0053] It should be understood that expressions such as "including" and "may include" that can be used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "including" and / or "having" can be interpreted as indicating a specific characteristic, number, operation, constituent element, component, or a combination thereof, but cannot be interpreted as excluding the existence or possibility of addition of one or more other characteristics, numbers, operations, constituent elements, components, or a combination thereof.

[0054] In addition, in this application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" can include A, can include B, or can include both A and B.

[0055] In the description of the embodiments of the present application, it should be noted that unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the two are connected and the relative position relationship after connection remains unchanged. "Rotational connection" means that the two are connected and can rotate relative to each other after connection. "Sliding connection" means that the two are connected and can slide relative to each other after connection. The orientation terms mentioned in the embodiments of the present application, such as "top", "bottom", "inside", "outside", "left", "right", etc., are only references to the direction of the accompanying drawings. Therefore, the orientation terms used are for better and clearer description and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation on the embodiments of the present application.

[0056] In addition, in the embodiments of the present application, mathematical concepts such as symmetry, equality, parallelism, and perpendicularity are mentioned. These limitations are all in view of the current technological level, rather than absolute strict definitions in the mathematical sense, and allow for a small amount of deviation. Approximations to symmetry, equality, parallelism, perpendicularity, etc. are all acceptable. For example, A is parallel to B means that A is parallel to B or approximately parallel to B, and the included angle between A and B can be between 0 degrees and 10 degrees. A is perpendicular to B means that A is perpendicular to B or approximately perpendicular to B, and the included angle between A and B can be between 80 degrees and 100 degrees.

[0057] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A low-loss, high-power radio frequency coaxial cable, characterized in that: The radio frequency coaxial cable comprises, from the inside to the outside, an inner conductor (1), an insulating layer, an outer conductor layer (2) and an outer sheath layer (3); the insulating layer comprises a polytetrafluoroethylene layer (4) and a cross-linked polyethylene foam layer (5); the polytetrafluoroethylene layer (4) is formed by twisting and wrapping a plurality of polytetrafluoroethylene hollow ropes; the cross-linked polyethylene foam layer (5) is made by extruding polyethylene foam and then irradiating and cross-linking it with a preset irradiation amount; the outer conductor layer (2) is a tubular structure formed by a smooth copper strip using a longitudinal wrapping process, and the outer surface of the tubular structure is provided with wrinkle patterns formed by embossing.

2. A low-loss, high-power radio frequency coaxial cable as claimed in claim 1, characterized in that: The inner diameter of the polytetrafluoroethylene hollow rope is 50% to 60% of its outer diameter.

3. A low-loss, high-power radio frequency coaxial cable as claimed in claim 1, characterized in that: The thickness of the polytetrafluoroethylene layer (4) is 1 / 10 of the thickness of the insulating layer. , and the thickness of the polytetrafluoroethylene layer (4) is equal to the outer diameter of a single polytetrafluoroethylene rope.

4. A low-loss, high-power radio frequency coaxial cable as claimed in claim 1, characterized in that: The preset irradiation amount is 8mrad~30mrad.

5. A low-loss, high-power radio frequency coaxial cable as claimed in claim 1, characterized in that: The opposite ends of the smooth copper strip are overlapped and fixed to form a linear overlapped edge, and the width of the overlapped edge is 9% to 15% of the unfolded width of the copper strip.

6. A low-loss, high-power radio frequency coaxial cable as claimed in claim 5, characterized in that: The thickness of the smooth copper strip is 0.06 mm to 0.15 mm.

7. A low-loss, high-power radio frequency coaxial cable as claimed in claim 1, characterized in that: A first adhesive layer is coated between the outer conductor layer (2) and the insulating layer.

8. The low-loss, high-power radio frequency coaxial cable according to claim 1, characterized in that: A second adhesive layer is coated between the outer conductor layer (2) and the outer sheath layer (3).

9. A low-loss, high-power leaky coaxial cable, characterized in that: The leaky coaxial cable comprises the structure of the radio frequency coaxial cable as claimed in any one of claims 1 to 8, and its outer conductor layer is provided with slots or gaps arranged in a periodic array.

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