Leakage cable

Abstract

The invention provides a leakage cable, which comprises an inner conductor and an insulator, and is characterized in that the insulator sleeves the outer side of the inner conductor; the outer conductor sleeves the outer side of the insulator, the outer conductor is provided with a plurality of leakage grooves and a plurality of leakage holes along the axis direction of the leakage cable, the leakage grooves and the leakage holes all penetrate through the side wall of the outer conductor, the leakage grooves are of strip-shaped structures, and the leakage grooves and the leakage holes are arranged crosswise along the axial direction of the leakage cable. By applying the technical scheme of the invention, the problems of high standing wave performance and limited application bandwidth of the leaky cable in the prior art can be solved.

Description

Technical Field

[0001] This invention relates to the field of leaky cable technology, and more specifically, to a leaky cable. Background Technology

[0002] Leaky cable is a transmission medium that radiates signals through a specific gap structure on the outer conductor. Its unique design enables it to provide continuous and uniform signal coverage along the cable axis, making it particularly suitable for wireless communication needs in narrow, enclosed spaces such as tunnels and elevator shafts.

[0003] Traditional leaky cables employ periodic slots on their outer conductor. These slots radiate electromagnetic waves transmitted within the leaky coaxial cable, and external electromagnetic waves can also enter the leaky cable through these slots, functioning as an antenna. However, these periodically placed slots exhibit standing waves or enhanced signal reflection at specific frequencies. The phase difference between the radiated or reflected electromagnetic waves from adjacent slots approaches 180°, resulting in in-phase superposition within the leaky cable. This superposition creates standing waves along the cable, forming a resonant point. Excessive reflection at the resonant point hinders effective signal transmission and radiation at and near that frequency, leading to high attenuation, high peak standing waves, and reduced bandwidth, frequency compatibility, and reliability in traditional leaky cables. Summary of the Invention

[0004] This invention provides a leaky cable to solve the problems of high standing wave performance and limited application bandwidth in existing leaky cables.

[0005] The present invention provides a leaky cable, which includes: an inner conductor and an insulator, the insulator being sleeved on the outside of the inner conductor; an outer conductor, the outer conductor being sleeved on the outside of the insulator, the outer conductor having multiple leaking grooves and multiple leaking holes arranged along the axial direction of the leaky cable, the leaking grooves and leaking holes all penetrating the sidewall of the outer conductor, the leaking grooves having a strip-shaped structure, and the leaking grooves and leaking holes being arranged crosswise along the axial direction of the leaky cable.

[0006] Furthermore, the leakage groove includes a first slot, a second slot, and a third slot. The first slot and the third slot are correspondingly arranged along the axial direction of the leakage cable, and the extension directions of the first slot and the third slot are both perpendicular to the axial direction of the leakage cable. The extension direction of the second slot has an angle with the axial direction of the leakage cable. One end of the second slot is connected to the first slot, and the other end of the second slot is connected to the third slot. Along the axial direction of the leakage cable, the projections of the second slot, the first slot, and the third slot all coincide.

[0007] Furthermore, along the axial direction of the leaking cable, two adjacent leaking grooves are symmetrically arranged.

[0008] Furthermore, the length of the first and third slots is L, 8mm≤L≤25mm, and the width of the first and third slots is W, 2mm≤W≤3mm.

[0009] Furthermore, the angle between the extension direction of the second slot and the axial direction of the leaking cable is α, where 10°≤α≤30°.

[0010] Furthermore, two adjacent leakage channels and two adjacent leakage holes are distributed at periodic intervals of P / 2, where the period P satisfies: Where m is an integer and m≤-1, c is the speed of light in a vacuum, f is the minimum operating frequency of the leaky cable, and ε is the equivalent relative permittivity of the insulator.

[0011] Furthermore, the insulator includes a first insulating layer and a second insulating layer, with the second insulating layer sleeved on the outside of the first insulating layer. The first insulating layer is made of foamed polyethylene with boron nitride, and the second insulating layer is made of foamed polyethylene.

[0012] Furthermore, the foaming density of the first insulating layer is 0.40 g / cm³. 3 -0.50g / cm 3 between.

[0013] Furthermore, the thickness ratio of the first insulating layer to the second insulating layer is between 1:2.7 and 1:2.9.

[0014] Furthermore, the outer outer wall of the outer conductor has multiple shape memory alloy wires spaced apart circumferentially along the leakage cable. The extension direction of the shape memory alloy wires is parallel to the axial direction of the leakage cable, and the shape memory alloy wires are arranged to avoid leakage grooves and leakage holes.

[0015] By applying the technical solution of this invention, leakage grooves and leakage holes are arranged crisscrossingly along the axial direction of the leakage cable. Due to the secondary effect of the surface wave on the outer conductor, electromagnetic waves transmitted inside the leakage cable can undergo pinhole diffraction at the leakage hole, exciting the electromagnetic field outside the outer conductor of the cable. This further excites the generation of induced charges on the surface of the outer conductor, thus generating a corresponding induced current along the outer surface of the outer conductor. Consequently, corresponding electromagnetic radiation is generated around the leakage cable, thereby increasing the bandwidth of the leakage cable. Furthermore, by setting leakage holes between two adjacent leakage grooves, the in-phase superposition of electromagnetic waves can be reduced, the peak standing wave height can be lowered, signal transmission efficiency and system stability can be improved, signal energy waste and equipment damage can be minimized, and signal coverage can be improved to ensure the frequency band compatibility and reliability of the leakage cable. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0017] Figure 1 A schematic diagram of the structure of the leaky cable provided by the present invention is shown;

[0018] Figure 2 A schematic diagram of the leakage groove and leakage hole provided by the present invention is shown;

[0019] Figure 3 A side view of the leaky cable provided by the present invention is shown;

[0020] Figure 4 A schematic diagram of the structure of the outer conductor provided by the present invention is shown;

[0021] Figure 5 This invention provides a schematic diagram of the structure of an outer conductor and a shape memory alloy wire in combination.

[0022] Figure 6 The simulation results of the standing wave of the leaky cable provided by the present invention are shown in the figure.

[0023] Figure 7 The diagram shows the attenuation simulation results of the leaky cable provided by the present invention.

[0024] The above figures include the following reference numerals:

[0025] 10. Inner conductor;

[0026] 20. Insulator; 21. First insulating layer; 22. Second insulating layer;

[0027] 30. Outer conductor; 31. Shape memory alloy wire;

[0028] 40. Leakage groove; 41. First slot; 42. Second slot; 43. Third slot;

[0029] 50. Leakage hole;

[0030] 60. Protective layer; 70. Sheath. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figure 1 As shown, this embodiment of the invention provides a leaky cable, which includes an inner conductor 10, an insulator 20, an outer conductor 30, a protective layer 60, and a sheath 70 from the inner layer to the outer layer. The sheath 70 can be made of halogen-free, low-smoke, flame-retardant polyolefin or low-density linear polyolefin, etc.; the protective layer 60 is a flame-retardant layer or a wrapping layer, which can be formed by wrapping with mica tape, non-woven fabric, or other suitable tapes. The protective layer 60 and the sheath 70 provide physical protection for the leaky cable. The inner conductor 10 is made of copper-clad aluminum and serves as the main carrier for signal and current transmission. The insulator 20 is sleeved on the outside of the inner conductor 10 to prevent short circuits between the inner conductor 10 and the outer conductor 30, and has a low dielectric constant to reduce dielectric loss during signal transmission. The outer conductor 30 is sleeved on the outside of the insulator 20. When the input voltage is applied, the outer conductor 30 and the inner conductor 10 will generate an axial induced current, and a magnetic field will be generated on the leakage cable accordingly. The outer conductor 30 is provided with multiple leakage grooves 40 and multiple leakage holes 50 along the axial direction of the leakage cable. The leakage grooves 40 and leakage holes 50 all penetrate the side wall of the outer conductor 30. In this way, the leakage grooves 40 and leakage holes 50 will cut off the current on the outer conductor 30 and generate excitation, directionally radiate electromagnetic waves, and receive electromagnetic waves to realize communication transmission.

[0033] Specifically, the leakage groove 40 has a strip-shaped structure. The leakage groove 40 decomposes the current, forming linearly polarized electromagnetic waves. The leakage groove 40 and the leakage hole 50 are arranged intersectingly along the axial direction of the leakage cable. Due to the secondary effect of the surface wave on the outer conductor 30, the electromagnetic waves transmitted inside the leakage cable can undergo pinhole diffraction at the leakage hole 50, exciting the electromagnetic field outside the outer conductor 30 of the cable. This further excites the generation of induced charges on the surface of the outer conductor 30, thus generating a corresponding induced current along the outer surface of the outer conductor 30. Consequently, corresponding electromagnetic radiation is generated around the leakage cable, thereby increasing the bandwidth of the leakage cable. Furthermore, because a leakage hole 50 is set between two adjacent leakage grooves 40, the in-phase superposition of electromagnetic waves can be reduced, the peak standing wave height can be lowered, the signal transmission efficiency and system stability can be improved, the waste of signal energy and equipment damage can be minimized, and the signal coverage can be improved to ensure the frequency band compatibility and reliability of the leakage cable.

[0034] Specifically in this application, such as Figure 2 As shown, the leakage channel 40 includes a first slot 41, a second slot 42, and a third slot 43. The first slot 41 and the third slot 43 are correspondingly arranged along the axial direction of the leakage cable, and the extension directions of the first slot 41 and the third slot 43 are both perpendicular to the axial direction of the leakage cable to generate horizontally polarized electromagnetic waves. The extension direction of the second slot 42 has an angle with the axial direction of the leakage cable to generate vertically polarized electromagnetic waves. One end of the second slot 42 is connected to the first slot 41, and the other end of the second slot 42 is connected to the third slot 43 to form a dual-polarized antenna structure, improving the communication effect of the leakage cable. Furthermore, along the axial direction of the leakage cable, the projections of the second slot 42, the first slot 41, and the third slot 43 all coincide, i.e., the leakage channel 40 forms an N-type structure, so that the electromagnetic waves are orthogonal, reducing the energy coupling of electromagnetic waves. This allows signals to be transmitted independently in the same frequency band and the same space, reducing signal crosstalk and improving spectral efficiency, thus improving the communication effect within a limited frequency band.

[0035] Furthermore, due to the pinhole diffraction at the leakage hole 50, circularly polarized electromagnetic waves can be radiated from the leakage hole 50. Combined with the linearly polarized electromagnetic waves radiated from the leakage groove 40, this can adapt to the polarization requirements of different receiving devices, eliminating the need for a separate transmission system for a single polarization and significantly improving the compatibility and flexibility of application scenarios. In addition, in areas with complex electromagnetic environments, this multi-polarization radiation capability can enhance anti-interference capabilities by switching or superimposing different polarization signals, reducing the risk of single polarization being susceptible to interference from specific directions, and further ensuring the reliability of signal transmission in the leaky cable.

[0036] Specifically, along the axial direction of the leaky cable, two adjacent leaky slots 40 are symmetrically arranged, which can make two adjacent second slots 42 symmetrically arranged. This allows the reflected wave phases of the two adjacent second slots 42 to cancel each other out, suppressing resonance peaks, reducing voltage standing wave ratio, widening the operating frequency band, and enabling the leaky cable to maintain stable transmission performance in a wider frequency range.

[0037] In some embodiments of this application, the leakage hole 50 can be a closed shape such as a circle or a square.

[0038] In the feasible embodiments of this application, the lengths of the first slot 41 and the third slot 43 are L, where 8mm ≤ L ≤ 25mm. When the lengths of the first slot 41 and the third slot 43 are less than 8mm, their lengths are insufficient, resulting in weak radiation energy, reduced signal coverage, and potential signal blind spots. When the lengths of the first slot 41 and the third slot 43 are greater than 25mm, the radiation intensity is enhanced, but this may lead to excessively strong signal directionality, uneven coverage, and increased signal loss in non-target directions. This application ensures the electromagnetic wave radiation effect and guarantees the communication performance of the leaky cable by setting the lengths of the first slot 41 and the third slot 43 between 8mm and 25mm. Specifically, the length L of the first slot 41 and the third slot 43 can be set to 8mm, 16mm, or 25mm.

[0039] In the feasible embodiments of this application, the widths of the first slot 41 and the third slot 43 are W, where 2mm ≤ W ≤ 3mm. When the widths of the first slot 41 and the third slot 43 are less than 2mm, their widths are too narrow, limiting the bandwidth of signal radiation and making it difficult to meet the simultaneous transmission requirements of multi-band signals such as 2.4GHz and 5GHz, easily leading to signal instability within the frequency band. When the widths of the first slot 41 and the third slot 43 are greater than 3mm, although the radiation bandwidth can be widened, the mechanical structural strength of the cable will be weakened, making the cable more prone to deformation and breakage during laying or use, and may also increase the risk of external interference intrusion. This application, by setting the widths of the first slot 41 and the third slot 43 between 2mm and 3mm, can ensure the multi-band communication requirements of the leaky cable, while also ensuring the structural strength of the leaky cable. Specifically, the widths of the first slot 41 and the third slot 43 can be set to 2mm, 2.3mm, or 3mm.

[0040] In the feasible embodiments of this application, the angle between the extension direction of the second slot 42 and the axial direction of the leaky cable is α, where 10°≤α≤30°. When α is less than 10°, the angle is too small, which can easily form a large signal dead zone on both sides of the cable, failing to meet the wide-area coverage requirements, and easily causing signal breaks within the coverage area, resulting in some locations not receiving stable signals and affecting communication continuity. When α is greater than 30°, the angle is too large, resulting in unilateral coverage and obvious areas of signal strength difference. By setting 10°≤α≤30°, the radiation direction and coverage uniformity of the leaky cable provided in this application can be guaranteed. Specifically, α can be set to 10°, 20°, or 30°.

[0041] Furthermore, the angle α between the extension direction of each pair of adjacent second slots 42 and the axial direction of the leaky cable is different. This arrangement can adjust the radiation direction of the signal, expand the coverage area, and reduce signal interference in adjacent areas.

[0042] Specifically, the distance between any leak hole 50 and any two adjacent leak grooves 40 is equal, and the two adjacent leak grooves 40 and the two adjacent leak holes 50 are distributed at a periodic interval of P / 2, wherein the period P needs to satisfy: Where m is an integer and m≤-1, c is the speed of light in a vacuum, f is the minimum operating frequency of the leaky cable, and ε is the equivalent relative permittivity of the insulator 20. Traditional leaky cables, due to the presence of periodic slots, exhibit standing waves or enhanced signal reflection at specific frequencies; these points are called resonant points. In this application, leaky holes 50 are arranged in a cyclic pattern with a period of P / 2. Since the spacing between these leaky holes 50 is much smaller than the operating wavelength of electromagnetic waves, the frequency bands of resonant points and their harmonics can be avoided, thus preventing the occurrence of 2x resonant points.

[0043] In yet another embodiment of this application, as Figure 1 and Figure 3 As shown, the insulator 20 includes a first insulating layer 21 and a second insulating layer 22. The second insulating layer 22 is sleeved on the outside of the first insulating layer 21. The first insulating layer 21 is made of foamed polyethylene with boron nitride, which makes the electromagnetic field more concentrated on the surface of the inner conductor and reduces the skin effect. The second insulating layer 22 is made of foamed polyethylene to form a soft boundary and constrain unnecessary leakage of electromagnetic waves.

[0044] Furthermore, the foaming density of the first insulating layer 21 is 0.40 g / cm³. 3 -0.50g / cm 3 Between, when the foaming density of the first insulating layer 21 is less than 0.40 g / cm³ 3 If the foaming density of the first insulating layer 21 is too low, the number and size of the internal bubbles will be large, which will lead to a decrease in the mechanical strength of the first insulating layer 21. Furthermore, the bubbles may cause internal voids or bubble rupture, resulting in a decrease in insulation performance. This will increase signal attenuation during transmission and may even trigger partial discharge, affecting communication quality. When the foaming density of the second insulating layer 22 is greater than 0.50 g / cm³, the insulation performance will be affected. 3 If the foaming density of the second insulation layer 22 is too high, resulting in fewer internal bubbles and a denser structure, it will reduce the flexibility of the leaky cable, increase construction difficulty, and raise the dielectric constant of the second insulation layer 22, leading to more severe attenuation of radio frequency signals during transmission and directly shortening the effective coverage distance of the cable. In this application, the foaming density of the first insulation layer 21 is set at 0.40 g / cm³. 3 -0.50g / cm3 This ensures both the communication performance and physical properties of the leaky cable. Specifically, the foaming density of the first insulation layer 21 can be set to 0.40 g / cm³. 3 0.45g / cm 3 Or 0.50g / cm 3 .

[0045] Specifically, the thickness ratio of the first insulating layer 21 to the second insulating layer 22 is between 1:2.7 and 1:2.9. When the thickness ratio is less than 1:2.9, the thickness of the first insulating layer 21 is too small, resulting in poor concentration of the electromagnetic field and hindering the reduction of the skin effect. When the thickness ratio is greater than 1:2.7, the thickness of the second insulating layer 22 is too small, leading to poor confinement of electromagnetic waves and causing unnecessary leakage, thus affecting communication quality. In this application, by setting the thickness ratio of the first insulating layer 21 to the second insulating layer 22 to be between 1:2.7 and 1:2.9, the stability of the electromagnetic field can be maintained, ensuring the overall communication performance of the leaky cable. Specifically, the thickness ratio of the first insulating layer 21 to the second insulating layer 22 can be set to 1:2.7, 1:2.8, or 1:2.9.

[0046] Furthermore, the insulation layer of traditional leaky cables is typically made of physically foamed polyethylene, with a density generally around 0.930 g / cm³. 3 The density of the foamed structure of the first insulating layer 21 is between -0.965 g / cm³. This application achieves this by comprehensively setting the foaming structure density of the first insulating layer 21 to 0.40 g / cm³. 3 -0.50g / cm 3 Between the first insulation layer 21 and the second insulation layer 22, the thickness ratio is between 1:2.7 and 1:2.9, which can reduce the overall weight of the insulator 20 by about 30%, further reducing the overall weight of the insulated cable and facilitating the installation of the communication system.

[0047] Reference Figure 4 As shown, the outer wall of the outer conductor 30 has multiple shape memory alloy wires 31 spaced circumferentially along the leaking cable. The extension direction of the shape memory alloy wires 31 is parallel to the axial direction of the leaking cable, and the shape memory alloy wires 31 are arranged to avoid the leaking groove 40 and the leaking hole 50. When the leaking cable is suspended on the clamp, the deformation caused by the change of seasons in summer and winter may cause the connector to fall off. By connecting the shape memory metal, the deformation of the leaking cable can be effectively reduced, and the tensile strength and bending fatigue life can be increased.

[0048] Specifically, the shape memory alloy wire 31 can be selected from NiTiNb alloy wire.

[0049] Reference Figure 5 As shown, the outer conductor 30 in this application is a corrugated copper tube, and the shape memory alloy wire 31 can be welded to the outer conductor 30 by welding. It does not need to be connected to each protrusion on the outside of the copper tube. Welding is done once every 3, 4 or 5 protrusions, which ensures the connection strength while reducing the processing cost.

[0050] The beneficial effects of the leaky cable provided in this application are explained below with reference to specific embodiments:

[0051] A simulation model was established to perform simulation calculations on the designed leaky cable at frequencies of 50-6000MHz. The length L of the first slot 41, the second slot 42, and the third slot 43 was set to 15mm, the slot width to 2.4mm, and the angle α between the extension direction of the second slot 42 and the axial direction of the leaky cable was 23°. The leak hole 50 was set as circular with a radius r of 3mm. Simultaneously, according to... Determine the period P, where c is 3×10⁸ m / s, f is the minimum operating frequency of the cable and is 50MHz, ε is the equivalent relative permittivity of the insulator 20 and is 1.248, and the center distance between two adjacent leakage grooves 40 is P / 2, i.e., 64.5mm.

[0052] simulation results of standing waves Figure 6 and attenuation simulation results Figure 7 Analysis shows that the leakage cable provided in this embodiment meets the usage requirements in terms of standing wave attenuation in the 700-3800MHz range. Figure 6 The image of the standing wave is consistent with the above analysis of the cutoff frequency and the resonant point, and the proposed matching structure of the leakage groove 40 and the leakage hole 50 reduces the standing wave near the resonant point to below 1.3 within both peaks, which is required for use. Figure 7 The attenuation of the structure with open holes is significantly smaller than that of the structure without open holes.

[0053] The technical solution applied in this application has the following technical advantages:

[0054] 1. The periodic aperture structure composed of N-type and hole-type on the outer conductor 30 can achieve broadband performance in the range of 700-3800MHz, effectively suppress the voltage standing wave ratio near the resonant point, and improve signal coverage efficiency.

[0055] 2. The insulator 20 uses a multi-layer insulating medium to reduce the skin effect, improve the electrical performance of the leaky cable, and increase its mechanical strength;

[0056] 3. The shape memory alloy wire 31 set on the outer conductor 30 can realize intelligent temperature compensation, effectively resist the change in the length of the leaky cable caused by thermal expansion and contraction, and further improve the performance of the leaky cable.

[0057] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0058] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0059] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0060] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0061] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A leaky cable, characterized in that, The leakage cable comprises: an inner conductor (10) and an insulator (20) sleeved outside the inner conductor (10); an outer conductor (30) sleeved outside the insulator (20), the outer conductor (30) is provided with a plurality of leakage grooves (40) and a plurality of leakage holes (50) along the axial direction of the leakage cable, the leakage grooves (40) and the leakage holes (50) all penetrate the side wall of the outer conductor (30), the leakage grooves (40) are in a strip structure, and the leakage grooves (40) and the leakage holes (50) are arranged in cross in the axial direction of the leakage cable.

2. The leaky cable of claim 1, wherein, The leakage grooves (40) comprise a first groove hole (41), a second groove hole (42) and a third groove hole (43), the first groove hole (41) and the third groove hole (43) are correspondingly arranged along the axial direction of the leakage cable, and the extension directions of the first groove hole (41) and the third groove hole (43) are both perpendicular to the axial direction of the leakage cable; the extension direction of the second groove hole (42) forms an angle with the axial direction of the leakage cable, one end of the second groove hole (42) is communicated with the first groove hole (41), the other end of the second groove hole (42) is communicated with the third groove hole (43), and along the axial direction of the leakage cable, the projection of the second groove hole (42), the projection of the first groove hole (41) and the projection of the third groove hole (43) all coincide.

3. The leaky cable of claim 2, wherein, Along the axial direction of the leakage cable, two adjacent leakage grooves (40) are symmetrically arranged.

4. The leaky cable of claim 2, wherein, The length of the first groove hole (41) and the third groove hole (43) is L, 8mm≤L≤25mm, and the width of the first groove hole (41) and the third groove hole (43) is W, 2mm≤W≤3mm.

5. The leaky cable of claim 2, wherein, The angle between the extension direction of the second groove hole (42) and the axial direction of the leakage cable is α, 10°≤α≤30°.

6. The leaky cable of claim 1, wherein, Two adjacent leakage grooves (40) and two adjacent leakage holes (50) are distributed at a period interval of P / 2, and the period P satisfies: ; where m is an integer and m < -1, c is the speed of light in a vacuum, f is the minimum frequency of use of the leaky cable; and ε is the equivalent relative permittivity of the insulator (20).

7. The leaky cable of claim 1, wherein, The insulator (20) comprises a first insulating layer (21) and a second insulating layer (22), the second insulating layer (22) is sleeved outside the first insulating layer (21), the first insulating layer (21) is a foamed polyethylene plus boron nitride material, and the second insulating layer (22) is a foamed polyethylene material.

8. The leaky cable of claim 7, wherein, The foamed structure density of the first insulating layer (21) is between 0.40 g / cm 3 -0.50 g / cm 3 .

9. The leaky cable of claim 7, wherein, The thickness ratio of the first insulating layer (21) to the second insulating layer (22) is between 1:2.7 and 1:2.

9.

10. The leaky cable of claim 1, wherein, The outer side wall of the outer conductor (30) is provided with a plurality of shape memory alloy wires (31) arranged at intervals in the circumferential direction of the leakage cable, the extension direction of the shape memory alloy wire (31) is parallel to the axial direction of the leakage cable, and the shape memory alloy wire (31) avoids the leakage groove (40) and the leakage hole (50).

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