Low-loss high-power radio frequency coaxial cable and leaky coaxial cable

Abstract

The invention belongs to the technical field of wireless communication, and more particularly relates to a low-loss high-power radio frequency coaxial cable and leaky coaxial cable, the radio frequency coaxial cable comprises an inner conductor, an insulating layer, an outer conductor layer and an outer sheath layer from inside to outside, and by optimizing the structures of the insulating layer and the conductor, the overall thermal resistivity of the cable is improved, and the overall performance of the cable is improved. And the attenuation performance of the cable and the heat resistance in a high-power application scene are improved. Compared with a high-power cable with a conventional structure, the attenuation test value of the radio-frequency coaxial cable under the specification of 3 / 8 inches is optimized by about 15% compared with the requirement on the premise of meeting the 125 DEG C temperature resistance grade; on the premise of meeting the 105 DEG C temperature resistance grade, the attenuation test value of the leaky coaxial cable under the 1 / 2 inch specification is optimized by about 17% compared with the standard requirement.

Description

Technical Field

[0001] The present application belongs to the field of wireless communication technology, 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 technology, high-power communication equipment has higher and higher performance requirements for 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 small size of the inner conductor relative to the outer conductor, the current density of the inner conductor is large and the heat generation is more serious. In some cases, the operating temperature of the inner conductor can reach above 100°C. Secondly, although the irradiation cross-linking of polyethylene insulation to make cross-linked polyethylene insulation can increase the operating temperature to above 125°C, the attenuation performance of the cross-linked polyethylene insulation layer is at least 10% worse than that of the polyethylene insulation layer before cross-linking. For RF coaxial cables and leaky coaxial cables for communications, the attenuation of the main frequency band is at least 3dB worse, which means that the power of the equipment needs to be doubled to ensure the original signal strength. However, higher power will lead to more serious heating, further testing the temperature resistance of the cable. Finally, the current conventional RF coaxial cable is generally used in the frequency band of 75 to 5000 MHz. For higher frequency and wider usage scenarios, the inner conductor of the cable is generally copper wire, copper tube, or silver is plated on the copper layer to further reduce attenuation and improve temperature resistance. However, other common metals with good temperature resistance are far less conductive than silver-plated copper, and their attenuation performance is far from meeting actual needs.

[0003] In general, the power usage of the cable is affected by the material's attenuation performance, heat dissipation performance, and temperature resistance performance. The existing coaxial cable structure can no longer meet the requirements of higher power usage scenarios, and it is urgently needed to optimize the structure and improve the materials to enhance its overall performance and meet the needs of high-power communication equipment. Summary of the invention

[0004] In view of the defects of the prior art, the purpose of this application is to provide a low-loss, high-power RF 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 cables do not meet the usage requirements in high-power usage scenarios.

[0005] To achieve the above-mentioned objectives, the present application provides a low-loss, high-power radio frequency coaxial cable, which includes, from the inside to the outside, an inner conductor, an insulating layer, an outer conductor layer and an outer sheath layer, the insulating layer including a polytetrafluoroethylene layer and a cross-linked polyethylene foam layer, the polytetrafluoroethylene layer being formed by twisting and wrapping a plurality of polytetrafluoroethylene hollow ropes, the cross-linked polyethylene foam layer being made by extruding polyethylene foam and then irradiating and cross-linking with a preset irradiation amount; the outer conductor layer is a tubular structure formed by a longitudinal wrapping process using a smooth copper strip, and the outer surface of the tubular structure is provided with wrinkle patterns formed by embossing.

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

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

[0008] Furthermore, the preset irradiation amount is 8mrad~30mrad.

[0009] Furthermore, 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.

[0010] Furthermore, the thickness of the smooth copper strip is 0.06 mm to 0.15 mm.

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

[0012] Furthermore, 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, a low-loss high-power leaky coaxial cable is provided. The leaky coaxial cable comprises the structure of the radio frequency coaxial cable as described above, and its outer conductor layer is provided with slots or gaps arranged in a periodic array.

[0014] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art: (1) The RF coaxial cable structure designed in this application uses a polytetrafluoroethylene hollow rope to twist and wrap a polytetrafluoroethylene layer outside the inner conductor, and then extrude a cross-linked polyethylene foam layer of 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 layer structure effectively prevents heat from being conducted outward from the inner conductor, so that the cable can still maintain good insulation performance when it is used at a higher power and generates a higher temperature, thereby improving the overall heat resistance of the cable. In addition, the cross-linked polyethylene foam layer has a good pore 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 irradiation, and forms an integral insulation layer with the polytetrafluoroethylene hollow layer, the two cooperate with each other to optimize the insulation layer's ability to transmit RF signals, and reduce the signal attenuation in the insulation layer compared to a single-layer cross-linked polyethylene or polytetrafluoroethylene insulation structure, thereby improving the attenuation performance of the cable.

[0015] (2) The RF coaxial cable structure designed in this application uses a smooth metal tape to wrap the outer conductor layer longitudinally, so that the outer conductor layer and the insulation layer fit closely together and exhaust air (air has strong heat insulation ability), so that the heat flow temperature of the outer insulation layer can be transferred to the outer layer 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 capacity of the cable, further strengthening the heat dissipation capacity of the cable and improving the cable attenuation performance. The outer conductor wrinkle pattern is formed by shallow corrugation after longitudinal wrapping, which increases the softness and heat dissipation area of ​​the cable. The corrugated corrugation formed by traditional welding corrugation has air between the corrugation and the insulation layer, which affects the heat dissipation capacity of the insulation layer to a certain extent. In addition, because the outer wrinkles of the outer conductor layer structure of this application are very shallow and tend to be flat, the outer conductor copper tape has no shrinkage and the resistance is smaller, which is conducive to reducing the attenuation of the cable.

[0016] (3) In the present application, the thickness of the polytetrafluoroethylene layer is designed to be 1 / 4 to 1 / 2 of the thickness of the entire insulating layer, and the polytetrafluoroethylene rope used is a hollow rope body, the inner diameter of the polytetrafluoroethylene hollow rope is 50% to 60% of its outer diameter, and the air volume ratio of the hollow rope body is in 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, thereby effectively reducing the dielectric constant. At the same time, the hollow structure of the hollow rope body has stronger thermal insulation performance than the solid structure, so that the inside of the polytetrafluoroethylene layer is subjected to a higher temperature while the temperature of the outer layer is relatively low, that is, the temperature level of the outer cross-linked polyethylene foam layer is lower than that of the inner polytetrafluoroethylene layer.

[0017] (4) In the present application, when there are no periodic slots or gaps on the outer conductor layer, 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. These two types of cables correspond to different application scenarios and have a wider range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram of the cross-sectional structure of a cable provided in an embodiment of the present application; Figure 2 It is a schematic diagram of the cross-sectional structure of a polytetrafluoroethylene hollow rope provided in an embodiment of the present application.

[0019] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-inner conductor; 2-outer conductor layer; 3-outer sheath layer, 4-polytetrafluoroethylene layer, 41-hollow structure, 42-polytetrafluoroethylene rope, 5-cross-linked polyethylene foam layer. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying 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.

[0021] The term "and / or" in this article is a description of the association relationship 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 at the same time, and B exists alone. The symbol " / " in this article indicates that the associated objects are in an or relationship, for example, A / B means A or B.

[0022] The terms "first" and "second" in the specification and claims herein are used to distinguish different objects rather than to describe a specific order of the objects. For example, a first response message and a second response message are used to distinguish different response messages rather than to describe a specific order of the response messages.

[0023] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0024] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more than two. For example, multiple processing units refer to two or more processing units, etc.; multiple elements refer to two or more elements, etc.

[0025] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0026] This embodiment provides a low-loss, high-power radio frequency coaxial cable (hereinafter referred to as the cable), such as Figure 1 and Figure 2 As shown, the cable comprises an inner conductor 1, an insulating layer, an outer conductor layer 2 and an outer sheath layer 3 from the inside to the outside, 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, and the cross-linked polyethylene foam layer 5 is made by extruding polyethylene foam and then subjecting it to radiation cross-linking with a preset amount of radiation; the outer conductor layer 2 is a tubular structure formed by a longitudinal wrapping process using a smooth copper strip, and the outer surface of the tubular structure (i.e., the surface on the side away from the insulating layer) is provided with shallow wrinkles formed by embossing, and these wrinkles can be arranged in a periodic array.

[0027] Specifically, the inner conductor 1 is a solid silver-plated copper wire or a hollow copper tube. The surface 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. The hollow copper tube as the inner conductor 1 has good 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, the current of the high-frequency signal is concentrated on the surface of the conductor. If the inner conductor 1 is too thick, the cost will increase. In addition, the size of the inner conductor 1, the insulation layer and the outer conductor jointly determine the characteristic impedance of the cable.

[0028] The hollow structure 41 in the polytetrafluoroethylene hollow rope 42 can reduce the equivalent dielectric constant of the material, reduce the loss of signal transmission, and reduce weight. On the other hand, the air volume ratio of the polytetrafluoroethylene hollow rope 42 may affect the mechanical strength and thermal conductivity. For example, the hollow polytetrafluoroethylene rope may reduce the use of 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 insulation layer, resulting in a larger temperature difference. Usually, the dielectric constant of microporous polytetrafluoroethylene material is about 1.5, and its temperature resistance level is above 200°C. The use of a hollow structure can greatly reduce the overall dielectric constant of the polytetrafluoroethylene hollow rope 42. According to the dielectric constant formula of the double-layer combined insulation structure (that is, the simplified formula when one layer is an air layer): (1) in, x is the ratio of the solid medium to the total volume of the structure. x When the microporous polytetrafluoroethylene medium reaches 75%, Taking 1.53, the dielectric constant of the hollow rope can be reduced to 1.4.

[0029] For example, the diameter of the inner conductor 1 in the cable is 3.6mm, the total outer diameter of the insulation layer (i.e., the outer diameter of the cross-linked polyethylene foam layer) is 11.8mm, the thickness of the insulation layer is 4.1mm, and the outer diameter of the polytetrafluoroethylene hollow rope constituting the polytetrafluoroethylene layer 4 in the insulation layer is 2.73mm. When some high-power equipment works at peak power for a long time, the power transmission value of the above-mentioned cable can reach more than about 20Kw, wherein the temperature difference between the inside and outside of the polytetrafluoroethylene layer 4 is about 10 degrees, and the actual temperature difference is nearly 20 degrees, plus the heat dissipation of the outer layer of the cable.

[0030] In order to solve the above problems, in the aforementioned insulating layer, the inner diameter of the polytetrafluoroethylene hollow rope constituting the polytetrafluoroethylene layer 4 is designed to be 50% to 60% of its outer diameter, such as 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59% or 60% of its outer diameter, or any ratio between any two of the above ratios.

[0031] The thickness of the polytetrafluoroethylene layer 4 is designed to be 1 / 10 of the thickness of the entire insulating layer. , and the thickness of the polytetrafluoroethylene layer 4 is equal to the outer diameter of a single polytetrafluoroethylene rope (hereinafter referred to as a single rope). For example, the thickness of the insulating layer is designed to be 4.1mm, the outer diameter of a single polytetrafluoroethylene hollow rope in the polytetrafluoroethylene layer is 1 / 4 of the thickness of the insulating layer, that is, 1.025mm, the diameter of its internal hollow area (that is, the inner diameter of the polytetrafluoroethylene hollow rope) is 0.41~0.61mm, and the hollow rate is about 25%~36%. A single polytetrafluoroethylene hollow rope is formed by extrusion and stretching of PTFE dispersed resin, and then about 11 hollow single ropes are spirally twisted onto the inner conductor 1 at a wrap angle of about 55° to form a single-layer honeycomb air gap structure (the porosity can reach more than 40%); according to the dielectric constant calculation formula of the double-layer combined insulation layer: (2) in d is the inner conductor diameter, D 1 is the outer diameter of the polytetrafluoroethylene layer, D 2 is the outer diameter of the cross-linked polyethylene foam layer, is the dielectric constant of the polytetrafluoroethylene layer (i.e., hollow rope), is the dielectric constant of the cross-linked polyethylene foam layer; according to the dimensions of this embodiment, the hollow ratio is 25%, the dielectric constant of the microporous polytetrafluoroethylene rope medium is 1.53, and the dielectric constant of the entire insulation layer can be reduced to about 1.39. The dielectric constant of the microporous polytetrafluoroethylene insulation layer of a general high-power cable can be optimally below 1.5, and the dielectric constant of the foamed cross-linked polyethylene foam layer of a high-power cable that meets 125°C can be optimally below 1.40; based on the above example, when the hollow ratio of the polytetrafluoroethylene rope and the dielectric constant of the material are selected to be better, the dielectric constant of the cable insulation layer can be further reduced.

[0032] The cross-linked polyethylene foam layer 5 is extruded, specifically using a PE base material (i.e. polyethylene) pre-mixed with a physical foaming agent (such as nitrogen, carbon dioxide foaming agent, nucleating agent), the foaming degree of the foaming layer structure is required to be greater than 70% to meet the high frequency and low loss requirements, the pore size is uniform and the pore size is between 20μm and 50μm. After extrusion, it is cooled step by step, specifically first using air cooling to gradually reduce its surface temperature, and then using a water cooling tank to control the temperature in sections to eliminate internal stress.

[0033] The aforementioned outer conductor layer 2 specifically utilizes multiple sets of conical dies and guide wheels to gradually curl the straight smooth copper strip into a closed cylinder (i.e., a tubular structure), and the opposite ends of the cylinder overlap and are fixed to form a linear overlapped edge, and the width of the overlapped edge is 9% to 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 overlapped edge is too wide, the diameter of the outer conductor layer will increase, reducing the tensile strength and bending performance of the cable. In addition, since there is more material in the overlapped edge, the flexibility and installation convenience of the cable will be affected, and the cable will be more easily deformed or damaged when subjected to external force. If the overlapped edge is too narrow, the shielding effect of the outer conductor layer will be poor. In addition, if the overlapped edge is too narrow, the copper strip will be unstable during the curling and fixing process, and it will be easy to loosen or dislocate, affecting the quality and consistency of the cable, and then affecting the electrical performance of the cable. In addition, a constant pressure (10MPa-30MPa) is applied by a high-temperature pressure roller (heated to about 80°C) to ensure uniform coating of the adhesive layer, and the roller-patterned copper strip is tightly wrapped around the insulation layer by a sizing and binding device.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] Compared with the insulation layer of pure polytetrafluoroethylene or highly irradiated cross-linked polyethylene structure, the low-irradiation cross-linked polyethylene has a lower temperature resistance grade, because under low irradiation, the molecular chain cross-linking degree in cross-linked polyethylene (XLPE) is low, and insufficient cross-linking makes the material easy to soften or deform at high temperature, thereby reducing its heat resistance. However, the coaxial cable structure obtained under the low-irradiation cross-linked polyethylene foam layer has better attenuation performance, because a moderate degree of cross-linking can optimize the dielectric properties of the material, and a lower degree of cross-linking can reduce defects and stress concentration inside the material, thereby reducing the attenuation of the signal during transmission. However, if the irradiation is too high (above 30Mrad), the attenuation performance will drop significantly, or if the irradiation is too low (below 8Mrad), the temperature resistance of the cable structure will not meet the application requirements.

[0038] Table 1 below shows the change in attenuation value of a cable of a specification provided in an embodiment of the present application after irradiation with different irradiances under the same experimental environment. It can be seen from Table 1 below that under the same frequency, the cable attenuation corresponding to the irradiance of 10 Mrad is the smallest. As the irradiance gradually increases, the cable attenuation deteriorates significantly. Therefore, the coaxial cable structure obtained under the low irradiance cross-linked polyethylene foam layer has better attenuation performance.

[0039] Table 1 Changes in attenuation values ​​of a cable of a certain specification under different irradiances

[0040] The polytetrafluoroethylene layer 4 of the inner insulating layer has a high temperature resistance level, which can reach above 200°C. The cross-linked polyethylene foam layer 5 located on the outside of the insulating layer does not need to reach the temperature resistance level of the polytetrafluoroethylene layer 4 on the inner side of 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. The inner polytetrafluoroethylene layer 4 can isolate the higher temperature directly brought by the inner conductor 1. When the temperature is transmitted to the cross-linked polyethylene layer, it is basically only about 105°C (that is, the temperature decreases step by step from the inside to the outside). Therefore, the overall temperature resistance of the cable is stronger.

[0041] In this embodiment, a first adhesive layer is coated between the outer conductor layer 2 and the insulating layer to achieve a tight connection between the two. Specifically, a thin layer of heat-resistant strong adhesive can be applied to tightly adhere the outer conductor layer 2 to the insulating layer. The thickness of the adhesive layer can be between 0.02mm and 0.1mm.

[0042] In a preferred embodiment, a second adhesive layer is coated between the outer conductor layer 2 and the outer sheath layer 3 to achieve a tight connection between the two, and the thickness of the adhesive layer can be between 0.02 mm and 0.1 mm. The outer sheath layer 3 is generally extruded by polyethylene or polyvinyl chloride and other materials. After molding, 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.

[0043] In another embodiment, based on the structure of the RF coaxial cable provided in the above embodiment, periodic slots or gaps are provided on the outer conductor layer 2 to form a leaky coaxial cable. The leaky coaxial cable allows part of the electromagnetic wave energy to leak out of the cable and radiate into the surrounding environment, while also allowing external electromagnetic waves to enter the cable through the slots. The above slots or gaps 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 a conventional slot shape used in the art, such as an eight-shaped, U-shaped, L-shaped, or elliptical shape. The size of the above gaps can be selected and designed according to the actual application scenario, and will not be repeated here.

[0044] In short, this application improves the overall thermal resistivity of the cable through the specific design of each layer structure of the coaxial cable, thereby improving the cable attenuation performance and heat resistance in high-power application scenarios. Compared with high-power cables of conventional structures, the low-loss high-power coaxial cable of this application optimizes the attenuation test value under the premise of meeting the 125°C temperature resistance level. For example, the 2700MHz attenuation test value of the 3 / 8-inch specification of the RF coaxial cable can reach 21.4dB / 100 meters, which is about 15% better than the standard requirement; under the premise of meeting the 105°C temperature resistance level, the 2700MHz attenuation test value of the 1 / 2-inch specification of the leaky coaxial cable is about 14.5dB / 100 meters, which is about 17% better than the standard requirement.

[0045] It should be understood that expressions such as "including" and "may include" that may be used in the present 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 the present application, terms such as "including" and / or "having" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0046] In addition, in the present application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0047] 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 relative position relationship after connection remains unchanged. "Rotational connection" means that the two are connected to each other and can rotate relative to each other after connection. "Sliding connection" means that the two are connected to each other and can slide relative to each other after connection. The directional terms mentioned in the embodiments of the present application, such as "top", "bottom", "inside", "outside", "left", "right", etc., are only reference directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation 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 therefore cannot be understood as a limitation on the embodiments of the present application.

[0048] In addition, in the embodiments of the present application, the mathematical concepts mentioned are symmetry, equality, parallelism, verticality, etc. These limitations are all for the current state of the art, rather than being absolutely strict definitions in a mathematical sense, and allow a small amount of deviation, approximation to symmetry, approximation to equality, approximation to parallelism, approximation to verticality, etc. are all possible. For example, A and B are parallel, which means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 and 10 degrees. A and B are perpendicular, which means that A and B are perpendicular or approximately perpendicular, and the angle between A and B can be between 80 and 100 degrees.

[0049] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on 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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