Low-loss low-standing-wave super-cut-off-frequency radio-frequency coaxial cable

Abstract

The invention belongs to the technical field of wireless communication, and particularly relates to a low-loss low-standing-wave super-cut-off-frequency radio frequency coaxial cable, an outer conductor of the cable is an annular corrugated pipe with an embossed structure, and tooth peaks and tooth grooves are alternately arranged on the surface of one side, facing an insulating layer, of the embossed structure in the axial direction. Each tooth peak is provided with an inverted V-shaped peak tip used for sinking into a foaming insulating layer, and each tooth groove is provided with an arc-shaped groove bottom used for containing the foaming insulating layer. According to the radio frequency coaxial cable, TE electromagnetic waves exceeding the cut-off frequency can be obviously improved, so that the radio frequency coaxial cable has the capabilities of low loss, low standing wave and super cut-off frequency working, can provide wider working frequency under the condition of large specification and size, and meets the requirements of low loss, low standing wave and high frequency during mobile communication networking. A standing wave diagram shows that the 3.3-3.7 GHz interference peak value of the cable disappears, which indicates that the cable can continue to work after exceeding the cut-off frequency, so that the working frequency of the original cable is widened, and the 5G working frequency band requirement is further met.

Description

Technical Field

[0001] The present application belongs to the field of wireless communication technology, and more specifically, relates to a low-loss, low-standing-wave, super-cutoff frequency radio frequency coaxial cable. Background Art

[0002] RF coaxial cable is a transmission medium widely used in antenna systems and is an important component connecting transmitters, receivers and antennas. Traditional RF coaxial cables are mainly used for signal transmission. In antenna systems, the design and characteristics of the cable have an important impact on the overall performance.

[0003] With the rapid development of antenna technology, the demand for high frequency bands is increasing. However, due to the influence of the cut-off working frequency of coaxial cables, when the cable exceeds a certain size, it is affected by high-order harmonics. After exceeding the cut-off frequency, the standing wave and transmission loss performance of coaxial cables are seriously deteriorated, resulting in that they can no longer be used after exceeding the cut-off frequency. For example, traditional The cut-off frequency of inch coaxial cable is about 2.7GHz, which cannot meet the current operating frequency of mobile communication 5G. As a result, when building mobile communication networks, only small-sized coaxial cables that can support higher frequencies can be selected. However, the transmission loss of small-sized coaxial cables is often greater than that of large-sized coaxial cables, which can easily cause waste of signal power, greatly reduce the coverage range of mobile communication equipment, and increase network construction costs. Summary of the invention

[0004] In response to the defects of the prior art or the need for improvement, the present application provides a low-loss, low-standing-wave, ultra-cutoff frequency RF coaxial cable, which can provide a wider operating frequency under large-size conditions and meet the requirements of low loss, low standing wave and high frequency in mobile communication networking.

[0005] The present application provides a low-loss, low-standing-wave, ultra-cutoff frequency radio frequency coaxial cable, which comprises an inner conductor, a foamed insulation layer, an outer conductor and a sheath layer from the inside to the outside, wherein: The outer conductor is an annular corrugated tube with a corrugated structure, and the corrugated structure has teeth peaks and teeth grooves alternately arranged axially on the side surface facing the foamed insulation layer. The tooth peaks have inverted V-shaped peaks for sinking into the foamed insulation layer, and the teeth grooves have arc-shaped groove bottoms for accommodating the foamed insulation layer.

[0006] Through the above technical scheme conceived by the present application, compared with the prior art, the present scheme designs the corrugated structure of the outer conductor in a specific shape. After the outer conductor is tightly wrapped around the outer periphery of the foamed insulation layer, the inverted V-shaped peak in the outer conductor can sink into the foamed insulation layer to form a physical bite, preventing relative sliding or separation between the outer conductor and the foamed insulation layer, and the arc-shaped groove bottom-shaped tooth groove can accommodate the foamed insulation layer, weakening the generation of gaps (especially radial gaps). This is conducive to reducing the reflection of the electromagnetic signal flowing from the inner conductor to the outer conductor when passing through different cutoff layers, improving the voltage standing wave ratio and transmission loss performance, especially for TE electromagnetic waves exceeding the cutoff frequency. The improvement is particularly obvious, so that the radio frequency coaxial cable has the ability to work with low loss, low standing wave and super cutoff frequency, and can provide a wider operating frequency under large-size conditions, meeting the requirements of low loss, low standing wave and high frequency in mobile communication networking.

[0007] As further preferred, the corrugation depth of the outer conductor satisfies the following relationship:

[0008]

[0009] in, Indicates the corrugation depth, represents the arc radius of the arc groove bottom, represents the corrugation pitch of the outer conductor, represents the angle between the surface of the tooth groove and the axis of the outer conductor.

[0010] As further preferred, the corrugation pitch of the outer conductor is 2mm-4mm.

[0011] As a further preference, the radial gap between the outer conductor and the foamed insulation layer is less than 1 mm.

[0012] As a further preference, the radial gap between the outer conductor and the foamed insulating layer is 0.2 mm-0.8 mm.

[0013] As further preferred, the compression ratio of the outer conductor is 1.005-1.05.

[0014] As a further preferred embodiment, the outer conductor is prepared by the following method: Corrugating the smooth outer conductor strip in a preset corrugation shape to obtain a corrugated conductor; Based on the outer surface of the cable core, the corrugated conductor is longitudinally rolled into a circle to obtain a corrugated round tube, wherein the cable core comprises an inner conductor and a foamed insulating layer wrapped around the outer circumference of the inner conductor; The corrugated round tube is preheated in a temperature range of 120°C to 180°C, and the longitudinal connecting edges of the corrugated round tube are welded to obtain an outer conductor without a gap on the outer circumference.

[0015] As a further preference, when executing the above-mentioned welding process, the corrugated round tube is pulled to the welding gun head for welding processing, and the real-time height information of the pre-welding point on the surface of the corrugated round tube is first collected, and the height of the welding gun head is adjusted based on the real-time height information, so that the height of the welding gun head and the outer surface contour of the corrugated round tube are always maintained at the same relative height position.

[0016] In general, the above technical solutions conceived by this application have the following technical advantages compared with the prior art: 1. The RF cable is designed with a corrugated structure of the outer conductor, and the inverted V-shaped peak in the outer conductor is sunk into the foamed insulation layer to form a physical bite, thereby preventing relative sliding or separation between the outer conductor and the foamed insulation layer. The arc-shaped groove bottom-shaped tooth groove accommodates the foamed insulation layer, weakening the generation of gaps, thereby reducing the reflection of the electromagnetic signal transmitted from the inner conductor to the outer conductor when passing through different cutoff layers, improving the voltage standing wave ratio and transmission loss performance, especially for TE electromagnetic waves exceeding the cutoff frequency. Under the same size specifications, the RF cable based on this design, the RF coaxial cable has the ability to work with low loss, low standing wave and super cutoff frequency, which is conducive to meeting the low loss, low standing wave and high frequency requirements in mobile communication networking.

[0017] 2. During the production process of the inner conductor of this RF cable, the corrugated round tube is preheated at a temperature range of 120℃~180℃, so that the corrugated round tube can be properly sunk into the foamed insulation layer, promoting the combination of the foamed insulation layer and the corrugated round tube, and reducing the thickness of the gap between the outer conductor and the foamed insulation layer (i.e., the radial gap). BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a low-loss, low-standing-wave, ultra-cut-off frequency radio frequency coaxial cable provided in an embodiment of the present application; Figure 2 is a cross-sectional view of an outer conductor provided in an embodiment of the present application; Figure 3 is a manufacturing process flow chart of the outer conductor provided in an embodiment of the present application; Figure 4 This is a voltage standing wave ratio test diagram of an existing radio frequency coaxial cable provided by the present application; Figure 5 This is a loss test diagram of an existing radio frequency coaxial cable provided by the present application; Figure 6This is a voltage standing wave ratio test diagram of a low-loss, low-standing-wave, super-cut-off frequency radio frequency coaxial cable provided in an embodiment of the present application; Figure 7 This is a loss test diagram of the low-loss, low-standing-wave, super-cutoff frequency RF coaxial cable 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. Foamed insulation layer; 3. Outer conductor; 4. Sheath layer; 5. Inverted V-shaped peak; 6. Arc-shaped groove bottom; 10. Radial gap. 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 following is combined with Figure 1-Figure 7 This application is described in further detail.

[0022] The present application embodiment discloses a low-loss, low-standing-wave, ultra-cutoff frequency radio frequency coaxial cable. Figure 1-Figure 2 The low-loss, low-standing-wave, super-cutoff-frequency radio frequency coaxial cable comprises, from the inside to the outside, an inner conductor 1, a foamed insulating layer 2, an outer conductor 3 and a sheath layer 4, wherein: the outer conductor 3 is an annular corrugated tube with a corrugated structure, and the corrugated structure has teeth peaks and teeth grooves alternately arranged along the axial direction on the side surface facing the foamed insulating layer 2, and the teeth peaks and the teeth grooves are smoothly connected, the teeth peaks have an inverted V-shaped peak tip 5 for sinking into the foamed insulating layer 2, and the teeth grooves have an arc-shaped groove bottom 6 for accommodating the foamed insulating layer 2.

[0023] Generally speaking, in a radio frequency coaxial cable, a radial gap 10 is formed between the outer conductor 3 and the foamed insulating layer 2, and the transmission speed of electromagnetic waves in the foamed insulating layer 2 is , c is the speed of light, v is the relative transmission rate, v is generally 0.8-0.95, and the radial gap 10 between the foamed insulation layer 2 and the outer conductor 3 is air, and its transmission speed is close to the speed of light c. However, when high-order harmonic TE electromagnetic waves are transmitted in different media, their magnetic field direction changes and reflections occur, which leads to the deterioration of standing waves and attenuation performance of RF coaxial cables after exceeding the cutoff frequency.

[0024] To this end, in this design, by designing the corrugation structure of the outer conductor 3 in a specific shape, after the outer conductor 3 is tightly wrapped around the outer periphery of the foamed insulation layer 2, the inverted V-shaped peak 5 in the outer conductor 3 can sink into the foamed insulation layer 2 to form a physical bite, preventing relative sliding or separation between the outer conductor 3 and the foamed insulation layer 2, and the arc-shaped groove bottom-shaped tooth groove can accommodate the foamed insulation layer 2, weakening the generation of the radial gap 10. This is conducive to reducing the reflection of the electromagnetic signal flowing from the inner conductor 1 to the outer conductor 3 when passing through different cutoff layers, improving the voltage standing wave ratio and transmission loss performance, especially for TE electromagnetic waves exceeding the cutoff frequency. The improvement is particularly obvious, so that the radio frequency coaxial cable has the ability to work with low loss, low standing wave and super cutoff frequency, and can provide a wider operating frequency under large-size conditions, meeting the requirements of low loss, low standing wave and high frequency in mobile communication networking.

[0025] In addition, the arc-shaped groove bottom 6 of the tooth groove can also help provide space when the cable is bent, avoiding the foamed insulating layer 2 from being squeezed and damaged, and buffering the bending deformation of the cable to ensure that the cable can be used stably for a long time.

[0026] It is understandable that the outer conductor 3 is made into an annular corrugated tube with a corrugated structure by a corrugation process. Under the corrugation process, the surface of the outer conductor 3 facing away from the foamed insulating layer 2 (i.e., the outer surface) basically presents the same specifications of the peaks, grooves, and corrugation depth as the surface of the corrugated structure facing the foamed insulating layer 2 (i.e., the inner surface). The peaks and grooves described later mainly refer to the peaks and grooves on the inner surface of the outer conductor 3.

[0027] Furthermore, in some embodiments, the corrugation depth of the outer conductor 3 satisfies the following relationship:

[0028]

[0029]

[0030] in, Indicates the corrugation depth, Indicates the arc radius of the arc groove bottom 6, represents the corrugation pitch of the outer conductor 3, It represents the angle between the inverted V-shaped peak 5 and the axis of the outer conductor 3.

[0031] Under this design, by designing the range of the relevant arc radius and angle in the corrugated profile of the outer conductor 3 and coupling the geometric structure of the inverted V-shaped peak 5 with the arc-shaped groove bottom 6, a better balance can be achieved between the penetration anchoring effect of the inverted V-shaped peak 5 and the deformation buffering effect of the arc-shaped groove bottom 6.

[0032] For cables, if the inverted V-shaped peak 5 is too sharp, the inverted V-shaped peak 5 may pierce the foamed insulation layer 2; if the inverted V-shaped peak 5 is too flat, the bite effect between the inverted V-shaped peak 5 and the foamed insulation layer 2 is not good. Set in A greater sinking depth can be obtained to obtain a good anchoring force without damaging the foamed insulation layer 2.

[0033] As for the arc groove bottom 6, if the curvature of the groove bottom is too large, stress is easily concentrated when the cable is bent, which is easy to cause fatigue fracture. If the groove bottom is too shallow, the capacity of accommodating the foamed insulation layer 2 is weakened. Therefore, under the value of the above relationship, the depth of the arc groove is moderate, which can better balance flexibility and strength. And the radial gap 10 formed is often small, and the radial gap 10 between the outer conductor 3 and the foamed insulation layer 2 (that is, the gap thickness between the outer conductor 3 and the foamed insulation layer 2) can basically reach 0.2mm-0.8mm.

[0034] Preferably, in some embodiments, the corrugation pitch of the outer conductor 3 is 2 mm-4 mm, and the radial gap 10 between the outer conductor 3 and the foamed insulating layer 2 is less than 1 mm. Furthermore, the radial gap 10 between the outer conductor 3 and the foamed insulating layer 2 ranges from 0.2 mm to 0.8 mm.

[0035] Under this design, based on the corrugated structure of the outer conductor 3, the compression ratio of the outer conductor 3 can reach 1.005-1.05, thereby ensuring that the cable meets the bending radius required by the engineering parameters, while making the gap between the outer conductor 3 and the foamed insulation layer 2 (i.e., the thickness of the air layer) smaller, which is beneficial to reduce the reflection of the electromagnetic signal flowing from the inner conductor 1 to the outer conductor 3 when passing through different cutoff layers, thereby improving the voltage standing wave ratio and transmission loss performance, especially for TE electromagnetic waves exceeding the cutoff frequency. It should be noted that the control of the radial gap between the outer conductor 3 and the foamed insulation layer 2 can be achieved based on the shape and structure design of the outer conductor 3 mentioned above, can also be achieved based on the manufacturing method, or can be achieved based on the optimization of the shape and structure design of the outer conductor 3 and the manufacturing method.

[0036] Further, such as Figure 3 As shown, in some embodiments, the outer conductor 3 is made by the following method: S1: corrugating the smooth strip of the outer conductor in a preset corrugation shape to obtain a corrugated conductor.

[0037] Generally speaking, the outer conductor smooth tape is first laid out, and then corrugated according to the required corrugation pitch and corrugation shape.

[0038] S2: Based on the outer surface of the cable core, the corrugated conductor is longitudinally rolled into a round shape to obtain a corrugated round tube, wherein the corrugated round tube is wrapped around the outer surface of the cable core. The cable core includes an inner conductor 1 and a foamed insulating layer 2 wrapped around the outer circumference of the inner conductor 1.

[0039] S3: Preheat the corrugated round tube at a temperature range of 120°C to 180°C.

[0040] During this process, preheating the corrugated tube can soften the foamed insulation layer 2 inside the tube, so that the foamed insulation layer 2 can properly sink into the corrugated tube, promote the combination of the foamed insulation layer 2 and the corrugated tube, and reduce the thickness of the radial gap 10.

[0041] S4: welding the longitudinal connecting edges of the corrugated circular tube (i.e., using the connecting edges of the strips as pre-welding locations for welding) to obtain an outer conductor 3 with no gaps on the outer circumference (i.e., a corrugated circular tube with no gaps).

[0042] In step S4, the corrugated round tube is pulled to the welding gun head for welding processing, and before the welding processing, the real-time height information of the pre-welding point on the surface of the corrugated round tube is first collected by the sensor, the real-time height information is obtained based on the sensor detection, and the real-time height information is transmitted to the controller through the sensor, and then the controller dynamically controls the displacement device through the algorithm based on the real-time height information, and adjusts the height of the welding gun head in real time through the position device, so that the height of the welding gun head and the outer surface contour of the corrugated round tube are always maintained at the same relative height position (that is, the welding gun head and the corrugated contour of the corrugated round tube are always controlled to maintain a specified spacing, which is pre-selected and set by the operator).

[0043] S5: The outer conductor 3 wrapped with the inner conductor 1 and the foamed insulating layer 2 is wound up (reeled up).

[0044] For ease of understanding, Figure 4 Shows an existing Inch specification RF coaxial cable (can be selected from the industry standard YD / T1092 Inch standard cable) standing wave ratio test chart, by Figure 4 It can be seen that the cable has an interference peak at 3.3GHz-3.7GHz after the cutoff frequency, which makes the cable unable to work in the 3.3GHz-3.7GHz frequency band. In a certain test, it was measured that the radial gap 10 between the outer conductor 3 and the foamed insulation layer 2 in the cable was 1.8mm on average.

[0045] in addition, Figure 5 Shows the existing Inch specification RF coaxial cable loss test chart, by Figure 5It can be seen that the loss index (i.e. attenuation performance) of the existing cable begins to fluctuate dramatically after 2.8 GHz, indicating that the loss fluctuation is large and unstable, causing the cable to have large losses after 2.8 GHz and be difficult to use.

[0046] Figure 6 A method based on this design is shown. The standing wave ratio test diagram of the RF coaxial cable with an inch specification. The difference between this cable and the above-mentioned existing RF coaxial cable is that the outer conductor 3 of the cable is an annular corrugated tube with a corrugated structure. The corrugated structure is alternately provided with tooth peaks and tooth grooves along the axial direction on the side surface facing the foamed insulation layer 2. The tooth peaks and tooth grooves are smoothly connected. The tooth peaks have an inverted V-shaped peak tip 5 for sinking into the foamed insulation layer 2, and the tooth grooves have an arc-shaped groove bottom 6 for accommodating the foamed insulation layer 2. Among them, the corrugation depth H is 0.51mm, the arc radius R of the arc-shaped groove bottom 6 is 0.5mm, and the angle between the tooth groove surface and the axis is The angle is 20°, the pitch P is 3 mm, the compression ratio is 1.015, and the radial gap 10 between the outer conductor 3 and the foamed insulating layer 2 of the final product is 0.3 mm on average.

[0047] Depend on Figure 6 It can be seen that the standing wave of the coaxial cable Figure 3 The interference peak between 3GHz and 3.7GHz is greatly reduced (almost disappears), indicating that the cable can continue to work after exceeding the cutoff frequency. That is, the operating frequency of the cable is broadened, basically meeting the 5G operating frequency band requirements.

[0048] in addition, Figure 7 The above-mentioned design based on this Inch specification RF coaxial cable loss test chart, by Figure 7 It can be seen that the attenuation performance of the cable begins to fluctuate slightly after 2.8 GHz, but the loss fluctuation is small and relatively stable, indicating that the loss is not large and the cable can continue to be used after 2.8 GHz.

[0049] It should be noted that Figure 4 and Figure 6 In the voltage standing wave ratio test diagram shown, the horizontal axis represents the test frequency of the standing wave, the vertical axis represents the test value of the standing wave, the "Trl" in the figure represents the "test window", "SWR" represents the "voltage standing wave ratio", "S11" represents the "instrument test port", "Ref" represents the "bottom line value", "Start" represents the "starting frequency", "Stop" represents the "stop frequency", and "Cor" represents the "calibrated state".

[0050] Figure 5 and Figure 7In the loss test diagram shown, the horizontal axis represents the attenuation test frequency, the vertical axis represents the attenuation test value, the "Trl" in the diagram represents the "test window", "S21" represents the "instrument test port", "Log Mag" represents the "attenuation index", "Ref" represents the "bottom line value", "Start" represents the "starting frequency", "Stop" represents the "stop frequency", and "IFBW" represents the "sweep bandwidth".

[0051] It should be understood that expressions such as "include" and "may include" 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 "include" and / or "have" 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.

[0052] It should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0053] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0054] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0055] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A low-loss, low-standing-wave, ultra-cut-off frequency radio frequency coaxial cable, characterized in that: The cable comprises, from the inside to the outside, an inner conductor (1), a foamed insulation layer (2), an outer conductor (3) and a sheath layer (4), wherein: The outer conductor (3) is an annular corrugated tube with a corrugated structure, wherein a surface of the corrugated structure facing the foamed insulation layer (2) is provided with tooth peaks and tooth grooves alternately along the axial direction, the tooth peaks having an inverted V-shaped peak tip (5) for sinking into the foamed insulation layer (2), and the tooth grooves having an arc-shaped groove bottom (6) for accommodating the foamed insulation layer (2).

2. The low-loss, low-standing-wave, ultra-cut-off frequency radio frequency coaxial cable according to claim 1, characterized in that: The corrugation depth of the outer conductor (3) satisfies the following relationship: in, Indicates the corrugation depth, represents the arc radius of the arc groove bottom (6), represents the corrugation pitch of the outer conductor (3), It represents the angle between the surface of the tooth groove and the axis of the outer conductor (3).

3. The low-loss, low-standing-wave, ultra-cut-off frequency radio frequency coaxial cable according to claim 1, characterized in that: The corrugation pitch of the outer conductor (3) is 2 mm to 4 mm.

4. The low-loss, low-standing-wave, ultra-cut-off frequency radio frequency coaxial cable according to claim 1, characterized in that: A radial gap (10) between the outer conductor (3) and the foamed insulating layer (2) is less than 1 mm.

5. The low-loss, low-standing-wave, ultra-cut-off frequency radio frequency coaxial cable according to claim 4, characterized in that: The radial gap (10) between the outer conductor (3) and the foamed insulating layer (2) is 0.2 mm to 0.8 mm.

6. The low-loss, low-standing-wave, ultra-cut-off frequency radio frequency coaxial cable according to claim 1, characterized in that: The compression ratio of the outer conductor (3) is 1.005-1.

05.

7. The low-loss, low-standing-wave, ultra-cut-off frequency radio frequency coaxial cable according to any one of claims 1 to 6, characterized in that: The outer conductor (3) is prepared by the following method: Corrugating the smooth outer conductor strip in a preset corrugation shape to obtain a corrugated conductor; The corrugated conductor is longitudinally rolled up based on the outer surface of the cable core to obtain a corrugated round tube, wherein the cable core comprises an inner conductor (1) and a foamed insulating layer (2) wrapped around the outer circumference of the inner conductor (1); The corrugated round tube is preheated in a temperature range of 120°C to 180°C, and the longitudinal connecting edges of the corrugated round tube are welded to obtain an outer conductor (3) with no gaps on the outer circumference.

8. The low-loss, low-standing-wave, ultra-cut-off frequency radio frequency coaxial cable according to claim 7, characterized in that: When executing the above welding process, the corrugated round tube is pulled to the welding gun head for welding processing, and the real-time height information of the pre-welding point on the surface of the corrugated round tube is first collected, and the height of the welding gun head is adjusted based on the real-time height information, so that the height of the welding gun head and the outer surface contour of the corrugated round tube are always maintained at the same relative height position.

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