A frequency-expanded leaky coaxial cable

Abstract

This application belongs to the field of wireless communication technology and relates to a frequency-expanded leaky coaxial cable. The frequency-expanded leaky coaxial cable successively includes an inner conductor, an insulating layer, an outer conductor, and a sheath layer from the inside to the outside. By designing the inner conductor as a square-wave tooth-shaped spiral corrugated tube and designing the corrugation pitch or compression ratio of the inner conductor to vary periodically along the axial direction, the inductance can be increased, the phase of high-frequency signals can be delayed, and the excitation of high-order modes can be effectively weakened. By setting the inner surface of the outer conductor as tooth peaks with inverted V-shaped peak tips and tooth grooves with arc-shaped groove bottoms, the gap can be reduced, and the reflection and transmission loss of electromagnetic signals can be reduced to meet the requirements of low loss, large coverage range, and wide frequency in mobile communication networking. The standing wave diagram of the product of this application shows that the interference peak value at 3.3 GHz - 3.7 GHz is greatly reduced or even basically disappears, enabling the frequency-expanded leaky coaxial cable to continue to work after the cut-off frequency and broadening the operating frequency.

Description

Technical Field

[0001] This application belongs to the field of wireless communication technology and relates to a frequency-expanded leaky coaxial cable. Background Art

[0002] A leaky coaxial cable is a special coaxial cable with electromagnetic wave radiation and reception functions, and is widely used in enclosed or complex spaces (such as tunnels, underground mines, subways, etc.) where wireless communication signals are difficult to directly cover.

[0003] With the rapid development of mobile communication, the requirement for the capacity of mobile communication channels is increasing, and the operating frequency of mobile communication systems is getting higher and higher. However, limited by the cut-off operating frequency of the leaky coaxial cable, after the leaky coaxial cable exceeds a certain size, affected by high-order harmonics, the standing wave and transmission loss performance of the leaky coaxial cable deteriorate severely after exceeding the cut-off frequency, resulting in the leaky coaxial cable being no longer usable after exceeding the cut-off frequency. This makes it difficult for large-size leaky coaxial cables to meet the working frequency requirements of current mobile communication 5G. As a result, when forming a mobile communication network, only small-size coaxial cables with greater transmission loss and smaller coverage range can be selected. Therefore, improvement is urgently needed. Summary of the Invention

[0004] Aiming at the defects of the prior art, this application provides a frequency-expanded leaky coaxial cable. This frequency-expanded leaky cable can continue to work normally after exceeding the cut-off frequency, and can provide a higher working frequency under the condition of large-size specifications, meeting the requirements of low loss, large coverage range and high frequency when forming a mobile communication network.

[0005] A frequency-expanded leaky coaxial cable provided by this application includes, from inside to outside in sequence, an inner conductor, an insulating layer, an outer conductor and a sheath layer, where:

[0006] The inner conductor is a spiral corrugated tube, the thread profile of the inner conductor presents a square waveform with a round chamfer, and the corrugation pitch of the inner conductor changes periodically along the axial direction, or the compression ratio of the inner conductor changes periodically along the axial direction;

[0007] The outer conductor is an annular corrugated tube with slots, and on the surface of the outer conductor facing the insulating layer, tooth peaks and tooth grooves are alternately arranged along the axial direction. The tooth peaks have inverted V-shaped peak tips for sinking into the insulating layer, and the tooth grooves have arc-shaped groove bottoms for accommodating the insulating layer.

[0008] Under this design, the inner conductor adopts a spiral thread design with a square-wave tooth profile, making the current direction basically perpendicular to or parallel to the cable axis, ensuring that the transmission direction is relatively precise, and reducing the transmission direction deviation of high-order mode interference signals. On this basis, the periodic fluctuation of the roll thread pitch or compression ratio can disperse the reflected signals after the super cutoff frequency, avoid periodic superposition, effectively suppress high-order harmonic excitation, optimize the anti-interference ability of the cable, and improve signal stability.

[0009] At the same time, by optimizing the structure of the outer conductor, the inverted V-shaped peaks in the outer conductor can sink (or be embedded) into the insulating layer to form a bite, preventing relative sliding or separation; the tooth grooves in the shape of an arc-shaped groove bottom in the outer conductor can accommodate the insulating layer, reduce the generation of the radial gap between the outer conductor and the insulating layer, and reduce the reflection of electromagnetic signals. This design can improve the voltage standing wave ratio of the cable, reduce the transmission loss, especially for the improvement of TE electromagnetic waves exceeding the cutoff frequency is particularly obvious.

[0010] Therefore, under the combined optimization design of the inner conductor and the outer conductor, by suppressing high-order harmonic excitation and reducing the reflection of electromagnetic signals, the operating frequency of the cable can be broadened and increased, making this leaky coaxial cable have significant low-loss and low-standing-wave capabilities, and can provide a relatively wide operating frequency under large-size conditions, meeting the requirements of low loss, low standing wave, and high frequency in mobile communication networking.

[0011] In addition, the square-wave thread design with round chamfers in the inner conductor and the arc-shaped groove bottom design of the tooth grooves in the outer conductor can provide deformation space for the cable, making the insulating layer not easily damaged by extrusion, while buffering the bending stress and extending the service life of the cable, which is beneficial for the cable to be bent and routed in complex space conditions to achieve a large-area coverage of mobile communication device signals.

[0012] As a further preference, a marking structure is provided on the outer surface of the sheath layer, and the marking structure and the slot holes are located at the radial two ends of the cable, and the marking structure extends along the axial direction of the sheath layer.

[0013] As a further preference, the inner conductor includes a tooth peak section and a tooth bottom section, where:

[0014] The axial length of the tooth peak section is greater than the axial length of the tooth bottom section;

[0015] The sum of the axial lengths of the tooth peak section and the tooth bottom section is equal to the roll thread pitch of the inner conductor.

[0016] As a further preference, the side wall surfaces of the tooth root section and the tooth peak section include a tooth root chamfer section, a linear flat section, and a tooth peak chamfer section, and the tooth peak chamfer section, the linear flat section, and the tooth root chamfer section are smoothly connected in sequence from outside to inside along the radial direction of the inner conductor.

[0017] As a further preference, the radial length of the linear flat section is not less than four times the radial length of the tooth root chamfer section, and the radial length of the tooth peak chamfer section is the same as the radial length of the tooth root chamfer section.

[0018] As a further preference, in the same periodic fluctuation change, the pitch / compression ratio of the corrugations of the inner conductor first decreases from large to small and then increases from small to large, or the pitch / compression ratio of the corrugations of the inner conductor first increases from small to large and then decreases from large to small.

[0019] As a further preference, the inner conductor is a single - helix or multi - helix corrugated tube.

[0020] As a further preference, the radial gap between the insulating layer and the outer conductor is less than 1 mm.

[0021] As a further preference, this cable is manufactured by the following method:

[0022] Provide a smooth outer conductor strip, and perform corrugation treatment on the smooth outer conductor strip in a preset corrugation shape to obtain a corrugated conductor;

[0023] Provide a cable core, and perform longitudinal wrapping and rounding treatment of the corrugated conductor on the outer surface of the cable core to obtain an outer conductor circular tube, wherein the cable core includes an inner conductor and an insulating layer wrapped around the outer peripheral surface of the inner conductor;

[0024] Perform hot extrusion molding of a sheath layer on the outer periphery of the outer conductor circular tube, and perform pre - heating treatment on the outer conductor circular tube based on the heat energy carried by the hot - extruded sheath layer. The pre - heating temperature is in the range of 120°C to 180°C, and then cool and shape it to obtain the cable.

[0025] Generally speaking, compared with the prior art by the above - conceived technical solution of this application, it mainly has the following technical advantages:

[0026] 1. By designing the inner conductor of this cable as a corrugated tube with a square - wave tooth profile and designing the pitch or compression ratio of the corrugations of the inner conductor to fluctuate periodically along the axial direction, the inductance can be increased, the phase of the high - frequency signal can be delayed, and the excitation of the high - order mode can be effectively weakened; and by setting the inner surface of the outer conductor as tooth peaks with inverted V - shaped peak tips and tooth grooves with arc - shaped bottom grooves, the gap can be reduced, and the reflection and transmission loss of electromagnetic signals can be reduced, so as to meet the requirements of low loss, large coverage range, and wide frequency in mobile communication networking.

[0027] 2. The design of the square waveform thread with rounded chamfers in the inner conductor and the arc-shaped groove bottom of the tooth grooves in the outer conductor can provide deformation space for the cable, making the insulating layer not easily damaged by extrusion, while buffering the bending stress and extending the service life of the cable. This is beneficial for the bending layout and routing of the cable under complex space conditions and facilitates the large-area coverage of the signal of mobile communication devices under complex spaces. Description of the Drawings

[0028] Figure 1 is a schematic structural diagram of a frequency-expanded leaky coaxial cable provided by an embodiment of the present application;

[0029] Figure 2 is a cross-sectional view of the outer conductor provided by an embodiment of the present application;

[0030] Figure 3 is a partial cross-sectional view of a frequency-expanded leaky coaxial cable provided by an embodiment of the present application;

[0031] Figure 4 is a diagram showing the square wave-shaped tooth profile of the inner conductor provided by an embodiment of the present application;

[0032] Figure 5 is a distribution diagram of the tooth bottom chamfer section, the linear flat section, and the tooth peak chamfer section provided by an embodiment of the present application;

[0033] Figure 6 is a cross-sectional schematic diagram of a frequency-expanded leaky coaxial cable provided by an embodiment of the present application;

[0034] Figure 7 is a manufacturing process flow chart of a frequency-expanded leaky coaxial cable provided by an embodiment of the present application;

[0035] Figure 8 is a voltage standing wave ratio test diagram of an existing leaky coaxial cable provided by an embodiment of the present application;

[0036] Figure 9 is a voltage standing wave ratio test diagram of a frequency-expanded leaky coaxial cable provided by an embodiment of the present application.

[0037] In all the drawings, the same reference numerals are used to represent the same elements or structures, where:

[0038] 1. Inner conductor; 2. Insulating layer; 3. Outer conductor; 4. Sheath layer; 4-1. Identification structure; 5. Inverted V-shaped peak tip; 6. Arc-shaped groove bottom; 7. Tooth bottom section; 8. Tooth peak section; 9. Tooth bottom chamfer section; 10. Linear flat section; 11. Tooth peak chamfer section; 100. Slot hole; 200. Radial gap. Detailed Embodiments

[0039] In order to make the objectives, technical solutions and advantages of this application more clear and understandable, the following further details this application in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0040] The following further details this application in conjunction with the attached Figures 1-9 drawings.

[0041] An embodiment of this application discloses a frequency-expanded leaky coaxial cable. Referring to Figures 1-6 , this frequency-expanded leaky coaxial cable sequentially includes an inner conductor 1, an insulating layer 2, an outer conductor 3, and a sheath layer 4 from the inside to the outside, where: the inner conductor 1 is a spiral corrugated tube, and the thread profile of the inner conductor 1 presents a square waveform with a round chamfer (that is, the surface thread of the inner conductor 1 presents a square waveform thread profile with a round chamfer), the corrugation pitch of the inner conductor 1 fluctuates periodically along the axial direction, or the compression ratio of the inner conductor 1 fluctuates periodically along the axial direction; and the outer conductor 3 is an annular corrugated tube with slots 100, and the surface of the outer conductor 3 facing the insulating layer 2 is alternately provided with tooth peaks and tooth grooves along the axial direction. The tooth peaks have inverted V-shaped peak tips 5 for sinking into the insulating layer 2, and the tooth grooves have arc-shaped groove bottoms 6 for accommodating the insulating layer 2.

[0042] Under this design, the inner conductor 1 adopts a square waveform thread design, making the current direction basically perpendicular to or parallel to the cable axis, ensuring that the transmission direction rule is relatively accurate, and being able to reduce the transmission direction deviation of high-order mode interference signals. On this basis, the periodic fluctuation of the corrugation pitch or compression ratio can disperse the reflected signals after the super cutoff frequency, avoid periodic superposition, thereby effectively suppressing high-order harmonic excitation, optimizing the anti-interference ability of the cable, and improving signal stability.

[0043] At the same time, by optimizing the structure of the outer conductor 3, the inverted V-shaped peak tips 5 in the outer conductor 3 can sink (or be embedded) into the insulating layer 2 to form an engagement, preventing the relative sliding or separation of the outer conductor 3 and the insulating layer 2; and the tooth grooves in the form of arc-shaped groove bottoms in the outer conductor 3 can accommodate the insulating layer 2, reducing the generation of the radial gap 200 between the outer conductor 3 and the insulating layer 2, and further reducing the reflection of electromagnetic signals; this design can improve the voltage standing wave ratio of the cable, reduce the transmission loss, especially for the improvement of TE electromagnetic waves exceeding the cutoff frequency is particularly obvious.

[0044] Under this design, by optimizing the structure of the inner conductor 1 and the outer conductor 3, suppressing high-order harmonic excitation and reducing the reflection of electromagnetic signals, the working frequency of the cable can be increased and broadened, making this leaky coaxial cable have significant low-loss and low-standing wave capabilities, and being able to provide a relatively wide working frequency under large specification conditions, meeting the requirements of low loss, low standing wave and high frequency in mobile communication networking.

[0045] Meanwhile, the design of the square-wave thread with rounded chamfers in the inner conductor 1 and the design of the arc-shaped groove bottom 6 of the tooth grooves in the outer conductor 3 can jointly provide deformation space for the cable, making the insulating layer 2 not easily damaged by extrusion, being able to buffer bending stress, and extending the service life of the cable. This is beneficial for users to arrange and route the cable in a bent manner under complex space conditions and to achieve a large-area coverage of the signal of the mobile communication device under complex spaces.

[0046] Furthermore, in some embodiments, the surface thread of the inner conductor 1 (i.e., the thread structure of the spiral corrugated tube) is obtained by the roll thread process. As Figure 4 shown, the inner conductor 1 includes a root section 7 and a crest section 8, and the root section 7 and the crest section 8 are alternately arranged along the axial direction of the inner conductor 1 and are smoothly connected to each other.

[0047] Preferably, the axial length of the crest section 8 is greater than the axial length of the root section 7, and the sum of the axial length of the crest section 8 and the axial length of the root section 7 is equal to the roll thread pitch of the inner conductor 1.

[0048] Generally, the axial length of the root section 7 is to of the axial length of the crest section 8. For easy understanding, Figure 4 the dimension label Y in

[0049] indicates the axial length of the crest section 8, the dimension label X indicates the axial length of the root section 7, and the dimension label P indicates the roll thread pitch of the inner conductor 1.

[0050] Furthermore, as Figure 5 shown, in some embodiments, the side wall surfaces of the root section 7 and the crest section 8 include a root chamfer section 9, a linear flat section 10, and a crest chamfer section 11, and the crest chamfer section 11, the linear flat section 10, and the root chamfer section 9 are smoothly connected in sequence from the outside to the inside along the radial direction of the inner conductor 1.

[0051] Preferably, the linear flat section 10 generally presents as a plane extending radially, and both the tooth root chamfer section 9 and the tooth peak chamfer section 11 are arc sections formed by 90-degree chamfers. Preferably, the radial length of the linear flat section 10 is not less than four times the radial length of the tooth root chamfer section 9, and the radial length of the tooth peak chamfer section 11 is preferably the same as the radial length of the tooth root chamfer section 9. Under this design, the surface profile of the inner conductor 1 is relatively round and smooth, which can optimize the electric field and protect the insulating layer 2.

[0052] For easy understanding, Figure 5 the dimension label R 1 in indicates the radial length of the tooth root chamfer section 9, the dimension label L indicates the radial length of the linear flat section 10, and the dimension label R 2 in indicates the radial length of the tooth peak chamfer section 11, and the dimension label D indicates the roll thread depth of the inner conductor 1.

[0053] Furthermore, in some embodiments, in the same periodic fluctuation change, the roll thread pitch or compression ratio of the inner conductor 1 first decreases from large to small and then increases from small to large. In some other embodiments, in the same periodic fluctuation change, the roll thread pitch or compression ratio of the inner conductor 1 first increases from small to large and then decreases from large to small.

[0054] Under this design, by regularly controlling the roll thread pitch or compression ratio of the inner conductor 1, the interference of high-order harmonics on the broadband leaky coaxial cable can be reduced, enabling the broadband leaky coaxial cable to continue to work effectively after exceeding the cut-off frequency.

[0055] It should be clear that when designing the roll thread pitch of the inner conductor 1 to fluctuate periodically along the axial direction, since the sum of the axial lengths of the tooth root section 7 and the tooth peak section 8 is equal to the roll thread pitch, at this time, the axial lengths of the tooth root section 7 and the tooth peak section 8 in the inner conductor 1 will also change accordingly with the change of the roll thread pitch.

[0056] Therefore, when the roll thread pitch of the inner conductor 1 fluctuates periodically along the axial direction, it is preferable to select the ratio of the axial length of the tooth root section 7 to the axial length of the tooth peak section 8 as a fixed ratio value, and then calculate the axial lengths of the tooth root section 7 and the tooth peak section 8 based on this fixed ratio value and the actual value of the roll thread pitch. Generally, this fixed ratio value is controlled and set by technicians according to standard specifications and experience.

[0057] It is clear that when the compression ratio of the inner conductor 1 is designed to fluctuate periodically along the axial direction, it is preferable to set the depth of the inner conductor 1 to fluctuate periodically along the axial direction, so as to achieve the purpose of the periodic fluctuation of the compression ratio of the inner conductor 1. Herein, the depth refers to the radial distance from the peak tip of the current tooth crest section 8 of the outer surface of the inner conductor 1 to the bottom valley of the adjacent tooth root section 7. By sequentially setting the radial distance between the tooth crest section 8 and the tooth root section 7 along the axial direction, the adjustment of the depth is realized.

[0058] Further, in some embodiments, the inner conductor 1 is a single - helix corrugated tube, and in some other embodiments, the inner conductor 1 is a multi - helix (such as double - helix) corrugated tube.

[0059] Further, in some embodiments, the insulating layer 2 is a foamed insulating layer, preferably made of polyethylene material.

[0060] Further, in some embodiments, the radial gap 200 between the insulating layer 2 and the outer conductor 3 is less than 1 mm. More preferably, the radial gap 200 between the insulating layer 2 and the outer conductor 3 is 0.2 mm - 0.8 mm.

[0061] By controlling the size of the radial gap 200, the purpose of reducing the reflection of electromagnetic signals can be achieved; generally speaking, the control of this radial gap 200 can be adjusted based on the above - mentioned surface structure design of the outer conductor 3, or can be controlled based on the production process, method, etc. of the cable, or can be achieved jointly based on the surface structure design and the manufacturing process, method.

[0062] Further, as Figure 7 shown, in some embodiments, the frequency - extended leaky coaxial cable is prepared by the following method:

[0063] S1: Provide a smooth outer - conductor strip, and perform corrugation treatment on the smooth outer - conductor strip in a preset corrugation shape to obtain a corrugated conductor.

[0064] Generally speaking, it is necessary to unwind the smooth outer - conductor strip first, and then perform corrugation treatment on the smooth outer - conductor strip according to the required corrugation pitch and corrugation shape.

[0065] S2: Provide a cable core, and perform longitudinal wrapping and circular rolling treatment of the corrugated conductor on the outer surface of the cable core to obtain an outer - conductor circular tube. Herein, the cable core includes the inner conductor 1 and the insulating layer 2 wrapped around the outer peripheral surface of the inner conductor 1. This cable core is usually fabricated on - site before the longitudinal wrapping and circular rolling treatment, or a pre - fabricated cable core can also be selected. In this step, the outer - conductor circular tube is coated on the outer surface of the insulating layer 2.

[0066] S3: Perform the thermal extrusion molding of the sheath layer 4 on the outer periphery of the outer conductor circular tube, and preheat the outer conductor circular tube based on the heat energy carried by the thermally extruded sheath layer 4. The preheating temperature is within the range of 120°C to 180°C, then cool and shape it to obtain the cable, and then wind up the cable into a coil.

[0067] In this step, by preheating the outer conductor circular tube, the insulating layer 2 inside the tube can be softened, enabling the outer conductor circular tube to appropriately sink into the insulating layer 2, promoting the combination of the insulating layer 2 and the outer conductor circular tube, and reducing the size of the radial gap 200. Generally speaking, compared with traditional cables, the radial gap 200 can be reduced by 20% - 50%.

[0068] In addition, in this method, it is preferable to traction the finished cable at a preset speed by a traction device. Generally, the speed should be selected between 5 meters per minute and 50 meters per minute.

[0069] In other embodiments, after completing the longitudinal wrapping and curling process, a preheating device such as an electric heating wire can also be used to preheat the outer conductor 3.

[0070] Furthermore, as Figure 6 shown, in some embodiments, a marking structure 4-1 is axially arranged on the outer surface of the sheath layer 4. The marking structure 4-1 and the slot hole 100 are located at the radial two ends of the cable respectively, and the marking structure 4-1 extends along the axial direction of the sheath layer 4. Among them, the marking structure 4-1 can be several slot hole marking lines. When the slot hole marking line is set as a single one, the single slot hole marking line should be at the 180° position of the slot hole center.

[0071] For easy understanding, Figure 8 shows a standing wave ratio test diagram of a traditional 1 inch (i.e., ) specification leaky coaxial cable (selected from the 1 inch standard specification cable specified in the industry standard YD / T2491). It can be seen from Figure 8 that there are large interference peaks in the range of 3.3 GHz - 3.7 GHz after the supercutoff frequency for this traditional cable. In a certain test, it was measured that the average radial gap 10 between the outer conductor 3 and the insulating layer 2 in this traditional cable is 1.8 mm.

[0072] Compared with the above traditional leaky coaxial cable, a leaky coaxial cable is different from the above traditional leaky coaxial cable in that: the inner conductor 1 of the leaky coaxial cable is a spiral corrugated tube, and the surface thread of the inner conductor 1 presents a square wave tooth shape with round chamfers (that is, the tooth shape of the thread structure presents a square wave shape with round chamfers), and the depth D of the inner conductor 1 fluctuates periodically along the axial direction (that is, the periodic fluctuation of the depth is used to achieve the periodic fluctuation of the compression ratio).

[0073] The depth D of the inner conductor 1 takes values of: 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm; and the depth changes cyclically in the order of 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.3 mm, 2.2 mm, 2.1 mm, 2.0 mm.

[0074] Among them, the pitch of the knurling of the inner conductor 1 is 10.2 mm, and the ratio of the axial length of the root section 7 to the axial length of the crest section 8 is: ; the axial length of the root section 7 is 3.06 mm, and the axial length of the crest section 8 is 7.14 mm.

[0075] Among them, the circular chamfer of the thread structure is a 90-degree chamfer, and the radius of the circular chamfer and the radial length of the linear flat section 10 are selected according to the real-time depth of the inner conductor 1, and the values are = = , when the depth is 2.0 mm, the radial length of the linear flat section 10 is 1.5 mm, the radius of the circular chamfer of the root chamfer section 9 is 0.25 mm, and the radius of the circular chamfer of the crest chamfer section 11 is 0.25 mm.

[0076] In addition, the outer conductor 3 of the leaky coaxial cable is an annular corrugated tube. On the surface of the outer conductor 3 facing the insulating layer 2, tooth crests and tooth grooves are alternately arranged along the axis. The tooth crests and tooth grooves are smoothly connected. The tooth crest has an inverted V-shaped peak tip 5 for sinking into the insulating layer 2, and the tooth groove has an arc-shaped groove bottom 6 for accommodating the insulating layer 2. Among them, the corrugation depth H is 0.51 mm, the arc radius R of the arc-shaped groove bottom 6 is 0.5 mm, and the angle between the tooth groove surface and the axis is 20°, the pitch P is 3 mm, the compression ratio is 1.015, and the average radial gap 200 between the outer conductor 3 and the insulating layer 2 of the final product is 0.3 mm.

[0077] Furthermore, Figure 9 shows a standing wave ratio test diagram of a 1 inch (i.e., ) leaky coaxial cable manufactured based on the above size design. It can be seen from Figure 9 that after adopting the design scheme of this application, the interference peak value of the standing wave of this frequency-expanded leaky coaxial cable in the range of 3.3 GHz - 3.7 GHz is greatly reduced, meeting the index requirement of the interference peak value ≤ 1.4 in the industry standard, enabling the cable to continue to work in the 3.3 GHz - 3.7 GHz stage after the cut-off frequency, significantly broadening the working frequency. Figure 3 .3 GHz - 3.7 GHz

[0078] It should be noted that Figure 8 and Figure 9In the shown voltage standing wave ratio test chart, the abscissa represents the test frequency, the ordinate represents the voltage standing wave ratio test value. In the figure, "Trl" represents "test window", "S11" represents "instrument test port", "SWR" represents "voltage standing wave ratio", "Ref" represents "bottom line value", "Start" represents "starting frequency", "Stop" represents "ending frequency", "Cor" represents "calibrated state", and "IFBW" represents "sweeping frequency bandwidth".

[0079] It should be noted that the compression ratio of the inner conductor 1 indicates the degree of dimensional change of the conductor material after being compressed or extruded during the production process. Specifically, it generally refers to the ratio of the outer diameter of the corrugated conductor to the diameter of the original smooth conductor.

[0080] It should be noted that the selection of values such as the corrugation pitch and depth in this leaky coaxial cable should comply with the relevant design standard regulations in the industry standard.

[0081] It should be noted that the slot holes 4-1 provided in the outer conductor 3 are preferably through holes, and the through holes are preferably distributed along the axial direction of the cable, mainly for signal transmission and reception.

[0082] It should be understood that expressions such as "including" 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 "including" and / or "having" can be interpreted as indicating a specific characteristic, number, operation, constituent element, component, or their combination, but cannot be interpreted as excluding the existence or possibility of addition of one or more other characteristics, numbers, operations, constituent elements, components, or their combination.

[0083] It should be understood that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to this application.

[0084] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, "a plurality of" means two or more, unless otherwise specifically defined.

[0085] In this application, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected to", "fixed", etc. shall 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0086] It is easy for those skilled in the art to understand that the above are only the preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of this application shall be included within the protection scope of this application.

Claims

1. A spectrum spreading leaky coaxial cable, characterized in that: The cable comprises, from the inside to the outside, an inner conductor (1), an insulating layer (2), an outer conductor (3) and a sheath layer (4), wherein: The inner conductor (1) is a spiral corrugated tube, the thread profile of the inner conductor (1) is a square wave with a rounded chamfer, the pitch of the roller corrugation of the inner conductor (1) fluctuates periodically along the axial direction, or the compression ratio of the inner conductor (1) fluctuates periodically along the axial direction; The outer conductor (3) is an annular corrugated tube with a slot (100); a surface of the outer conductor (3) facing the insulating layer (2) is provided with tooth peaks and tooth grooves alternately arranged along the axial direction; the tooth peaks have inverted V-shaped peaks (5) for sinking into the insulating layer (2); and the tooth grooves have arc-shaped groove bottoms (6) for accommodating the insulating layer (2); The inner conductor (1) comprises a tooth bottom section (7) and a tooth peak section (8); the depth of the inner conductor (1) is the radial distance from the peak of the tooth peak section (8) to the bottom valley of the tooth bottom section (7); the depth of the inner conductor (1) is periodically fluctuated to cause the compression ratio to fluctuate periodically.

2. The extended spectrum leaky coaxial cable according to claim 1, characterized in that: The outer surface of the sheath layer (4) is provided with an identification structure (4-1), the identification structure (4-1) and the slot (100) are arranged at two radial ends of the cable, and the identification structure (4-1) extends along the axial direction of the sheath layer (4).

3. The extended spectrum leaky coaxial cable according to claim 1, characterized in that: The axial length of the tooth peak section (8) is greater than the axial length of the tooth bottom section (7); The sum of the axial length of the tooth peak section (8) and the axial length of the tooth bottom section (7) is equal to the roller pitch of the inner conductor (1).

4. The extended spectrum leaky coaxial cable according to claim 3, characterized in that: The side wall surfaces of the tooth bottom section (7) and the tooth peak section (8) include a tooth bottom chamfered section (9), a linear flattened section (10) and a tooth peak chamfered section (11), and the tooth peak chamfered section (11), the linear flattened section (10) and the tooth bottom chamfered section (9) are smoothly connected in sequence from outside to inside along the radial direction of the inner conductor (1).

5. The extended spectrum leaky coaxial cable according to claim 4, characterized in that: The radial length of the linear flattening section (10) is not less than four times the radial length of the tooth bottom chamfering section (9), and the radial length of the tooth peak chamfering section (11) is the same as the radial length of the tooth bottom chamfering section (9).

6. The extended spectrum leaky coaxial cable according to claim 1, characterized in that: In the same periodic fluctuation change, the roller pitch or compression ratio of the inner conductor (1) first changes from large to small and then changes from small to large, or the roller pitch or compression ratio of the inner conductor (1) first changes from small to large and then changes from large to small.

7. The extended spectrum leaky coaxial cable according to claim 1, characterized in that: The inner conductor (1) is a single-helix or multi-helix spiral corrugated tube.

8. The extended spectrum leaky coaxial cable according to any one of claims 1 to 7, characterized in that: The radial gap (200) between the insulating layer (2) and the outer conductor (3) is less than 1 mm.

9. The extended spectrum leaky coaxial cable according to any one of claims 1 to 7, characterized in that: The cable is manufactured by the following method: Providing a smooth outer conductor belt, and performing roller processing on the smooth outer conductor belt in a preset roller shape to obtain a roller-corrugated conductor; A cable core is provided, and the outer surface of the cable core is subjected to longitudinal wrapping and rounding treatment of the corrugated conductor to obtain an outer conductor round tube, wherein the cable core comprises an inner conductor (1) and an insulating layer (2) wrapped around the outer circumference of the inner conductor (1); The outer circumference of the outer conductor round tube is subjected to hot extrusion molding of a sheath layer (4), and the outer conductor round tube is preheated based on the heat energy of the hot extruded sheath layer (4), the preheating temperature being within a temperature range of 120° C. to 180° C., and then cooled and molded to obtain a cable.

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