Leaky coaxial cable and preparation and application method thereof

Abstract

The invention relates to a leaky coaxial cable and preparation and application methods thereof. The leaky coaxial cable comprises an inner conductor; the insulator wraps the inner conductor; the outer conductor is arranged on the outer surface of the insulator; the outer conductor is formed by spirally and continuously wrapping strip-shaped flexible copper foil on an insulator; the flexible copper foils of the adjacent circles are in lap joint with a preset length, and the preset length meets the condition that when the bending radius of the leaky coaxial cable is larger than or equal to a preset value, the flexible copper foils of the adjacent circles are kept in a lap joint state; when the bending radius of the leaky coaxial cable is smaller than a preset value, adjacent circles of flexible copper foils are separated from each other to form a gap; and the sheath wraps the outer conductor. The flexible cable can be simultaneously suitable for scenes needing signal coverage or not needing signal coverage, an adaptive signal coverage function can be achieved by changing the lap joint state between the adjacent flexible copper foils of the outer conductor through bending, and the signal coverage degree can be autonomously selected according to the actual situation; therefore, the method has the remarkable advantages of low loss, wide application range, high controllability, high adjustable degree and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of cables, and in particular to a leaky coaxial cable and a preparation and application method thereof. Background Art

[0002] In the transmission and coverage process of the Industrial Internet of Things, within the range of spatial propagation, some occasions do not require signal coverage, while other occasions require intensive signal coverage.

[0003] Leaky coaxial cable is a special type of coaxial cable that not only transmits signals, but also functions as an antenna. By controlling the opening of the outer conductor, the leaky coaxial cable can evenly radiate and receive controlled electromagnetic wave energy along the line, covering the blind area of ​​the electromagnetic field to achieve smooth mobile communication. The insulation of this cable adopts a uniform, fine, and closed micro-bubble structure with high physical foaming. Compared with the traditional air insulation structure, it is more uniform and stable in transmission parameters such as characteristic impedance, standing wave coefficient, and attenuation, and can resist the intrusion of moisture into the cable in a humid environment, thereby improving the service life and stability of the product.

[0004] The working principle of the existing leaky coaxial cable is that part of the electromagnetic energy transmitted inside the cable can be sent to the external environment through the slots on the outer conductor of the coaxial cable, and at the same time, the external electromagnetic energy can also be transmitted into the cable to achieve coupling between the internal electromagnetic field and the external electromagnetic waves. The electrical performance of this cable is mainly measured by the longitudinal attenuation constant and coupling loss. The longitudinal attenuation constant is an important characteristic for assessing the energy loss of electromagnetic waves transmitted inside the cable, while the coupling loss describes the amount of energy generated by coupling outside the cable and received by the external antenna.

[0005] As can be seen from the above, the existing leaky coaxial cable needs to open slots on the outer conductor of the coaxial cable. However, the performance of the leaky coaxial cable is greatly affected by the surrounding environment, because a small amount of energy inside the cable propagates in the external environment near the outer conductor. This means that the attenuation performance of the cable depends not only on the type of insulation layer and the size of the cable, but also on the arrangement of the slots on the outer conductor. Different types of leaky coaxial cables need to be optimized for specific frequency ranges, which limits their versatility at different frequencies. It is necessary to open slots of different types and sizes on the outer conductor of the coaxial cable. However, the equipment for manufacturing leaky coaxial cables in the industry still uses traditional equipment. Punches are generally used for slot processing, which is quite bulky, has low production efficiency and causes rapid mold wear. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention discloses a leaky coaxial cable and a preparation and application method thereof.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A leaky coaxial cable comprises: an inner conductor extending a preset distance in one direction; an insulator wrapping the inner conductor; an outer conductor arranged on the outer surface of the insulator; the outer conductor comprises a strip of flexible copper foil spirally and continuously wrapped around the insulator; adjacent turns of the flexible copper foil overlap by a preset length, and the preset length satisfies: when the bending radius of the leaky coaxial cable is greater than or equal to a preset value, the adjacent turns of the flexible copper foil maintain an overlapping state; when the bending radius of the leaky coaxial cable is less than a preset value, the adjacent turns of the flexible copper foil are separated from each other to form a gap; and a sheath wrapping the outer conductor.

[0009] Its further technical feature is that the inner conductor is formed by twisting a plurality of copper wires; and the diameter of the inner conductor is 3.55 mm-3.60 mm.

[0010] Its further technical feature is that the insulator is made of foamed polyethylene material; the outer diameter of the insulator is 9.8mm-10.0mm.

[0011] Its further technical feature is that the thickness of the outer conductor is 0.05mm-0.1mm.

[0012] Its further technical feature is that the sheath is a low-smoke halogen-free flame-retardant sheath.

[0013] Its further technical feature is that the single bending radius of the leaky coaxial cable is 35 mm; the multiple bending radius of the leaky coaxial cable is 70 mm.

[0014] The present invention also provides a method for preparing a leaky coaxial cable, which comprises the following steps: step S1, preparing an inner conductor, wherein the inner conductor extends a preset distance in one direction; step S2, uniformly covering an insulator outside the inner conductor; step S3, continuously winding a strip of flexible copper foil in a spiral manner on the outside of the insulator to form an outer conductor; adjacent turns of the flexible copper foil overlap by a preset length, and the preset length satisfies: when the bending radius of the leaky coaxial cable is greater than or equal to a preset value, the adjacent turns of the flexible copper foil maintain an overlapping state; when the bending radius of the leaky coaxial cable is less than a preset value, the adjacent turns of the flexible copper foil are separated from each other to form a gap; step S4, coating the outer conductor with a layer of protective material to form a sheath.

[0015] Its further technical feature is that in step S1, a plurality of copper wires are twisted together to form a strand.

[0016] The present invention also provides an application method of a leaky coaxial cable, which comprises: step a, determining the signal coverage requirement to determine the position on the leaky coaxial cable where signal leakage is required; step b, bending the position on the leaky coaxial cable where signal leakage is required, with a bending radius smaller than the preset value, so that the flexible copper foils of adjacent circles at the corresponding position are separated from each other to form a gap.

[0017] Its further technical feature is that in step b, the bending radius is determined according to the strength required for signal coverage.

[0018] The above technical solution of the present invention has the following advantages compared with the prior art:

[0019] The leaky coaxial cable and its preparation and application methods described in the present invention can be applied to scenarios where signal coverage is required or not. In areas where signal coverage is not required, it can be used as a feeder to perform conventional signal transmission operations. In areas where signal coverage is required, it can achieve adaptive signal coverage by bending to change the overlapping state between adjacent turns of flexible copper foil of the outer conductor. In particular, the present application can independently select its signal coverage degree according to actual conditions. Based on this, compared with conventional leaky cables at this stage, the present application has the significant advantages of low loss, wide application range, strong controllability and high degree of adjustability, providing new ideas for the preparation and use of leaky cables. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0021] Figure 1 is a schematic diagram of an existing leaky coaxial cable.

[0022] Figure 2 Schematic diagram of a leaky coaxial cable in the present invention.

[0023] Figure 3 It is a cross-sectional view of the leaky coaxial cable in the present invention.

[0024] Explanation of the reference numerals in the specification: 10, inner conductor; 20, insulator; 30, outer conductor; 40, sheath; 50, gap. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0026] Embodiment 1

[0027] See also Figure 1 and Figure 2 As shown, this embodiment provides a leaky coaxial cable, which includes: an inner conductor 10, which extends a preset distance in one direction; an insulator 20, which wraps the inner conductor 10; an outer conductor 30, which is arranged on the outer surface of the insulator 20; the outer conductor 30 includes a strip of flexible copper foil spirally and continuously wrapped around the insulator 20; adjacent turns of the flexible copper foil overlap a preset length, and the preset length satisfies: when the bending radius of the leaky coaxial cable is greater than or equal to a preset value, the adjacent turns of the flexible copper foil maintain an overlapping state; when the bending radius of the leaky coaxial cable is less than a preset value, the adjacent turns of the flexible copper foil are separated from each other to form a gap 50; a sheath 40, wrapping the outer conductor 30.

[0028] The leaky coaxial cable described in this embodiment can be used in scenarios where signal coverage is required or not. In areas where signal coverage is not required, it can be used as a feeder to perform conventional signal transmission operations. In areas where signal coverage is required, it can achieve adaptive signal coverage by changing the overlapping state between adjacent turns of flexible copper foil of the outer conductor 30 by bending. In particular, the present application can independently select its signal coverage degree according to actual conditions. Based on this, compared with conventional leaky cables at this stage, the present application has the significant advantages of low loss, wide application range, strong controllability and high degree of adjustability, providing new ideas for the preparation and use of leaky cables.

[0029] In this embodiment, the inner conductor 10 is used to transmit electromagnetic signals, and is preferably a structure formed by twisting multiple copper wires. Specifically, the inner conductor 10 in this embodiment is formed by twisting 49 copper wires with a diameter of 0.52 mm. Further, the inner conductor 10 in this embodiment has a diameter of 3.60 mm, which not only improves the tensile strength of the inner conductor 10, but also greatly improves its flexibility and plasticity compared to the conventional inner conductor 10, so as to facilitate subsequent cooperation and bending with the outer conductor 30.

[0030] The insulator 20 in this embodiment is wrapped around the inner conductor 10, and is used to isolate the inner conductor 10 and the outer conductor 30, prevent the signal from being short-circuited, and maintain the transmission quality of the signal. The base material is preferably a foamed polyethylene material (PE). The foamed polyethylene (PE) insulator 20 has good insulation performance, can effectively isolate the inner conductor 10 and the outer conductor 30, prevent the signal from being short-circuited, ensure the transmission quality of the signal, and can reduce the energy loss caused by signal attenuation. At the same time, the foamed PE material is relatively light and soft, and can adapt to various bending and stretching requirements of the cable during installation and wiring, and provide good mechanical properties. In addition, the foamed polyethylene also has the advantages of long service life, flame retardancy, easy recycling and reuse, and low cost. In different embodiments, the insulating layer can also be set to other insulating materials according to actual use requirements, and the present invention does not make specific restrictions on this.

[0031] Furthermore, the outer diameter of the insulator 20 in this embodiment is 9.90 mm. This size range allows the cable to adapt to various pipes and grooves during installation, reduces the need for special size adapters, and ensures that the copper wire of the outer conductor 30 can form cracks on the outside of the insulation, so that the signal can be leaked out through the gap 50 of the crack to cover the required area. In actual use, the operator can adjust the width of the crack of the outer conductor 30 by changing the bending radius of the leaky coaxial cable, thereby controlling the amount of signal radiation.

[0032] In the leaky cable, the outer conductor 30 is used to realize the leakage transmission of the signal. It can transmit electromagnetic signals through the surface leakage part so as to transmit or receive signals under specific conditions. The outer conductor 30 in this embodiment is formed by a 0.1mm strip-shaped flexible copper foil spirally and continuously wrapped around the insulator 20. In this embodiment, the flexible copper foil of adjacent circles overlaps a preset length, and it is necessary to ensure that the single bending radius of the leaky coaxial cable reaches 35mm and the multiple bending radius reaches 70mm. In this way, not only can the adjustment of different leakage gaps be achieved, but also the cable can be used in more scenarios and has the effect of extending its service life. Further, the thickness of the outer conductor 30 in this embodiment is 0.1mm. Further, after testing, this embodiment has been found that when it is necessary to radiate the signal to the area, the coaxial leaky cable can form a gap 50 outside the insulator 20 when the bending diameter is approximately 10cm to 15cm, so that the signal is leaked out of the gap 50 to cover the signal where it needs to be covered.

[0033] In this embodiment, the sheath 40 is a low-smoke halogen-free flame-retardant sheath 40, thereby making the leaky coaxial cable have obvious advantages in terms of safety, environmental protection, durability, fire resistance and cost-effectiveness.

[0034] Furthermore, after partial performance testing of the leaky coaxial cable in this embodiment, it is found that the bending radius of the leaky coaxial cable in this embodiment can be at least 3.5 cm, the maximum tensile tension can be up to 700 N, the operating frequency range is 5 MHz-6 GHz, the characteristic impedance is 50 Ω ± 2 Ω, the insulation resistance is greater than or equal to 5000 MΩ km, and it can be ensured that it will not be broken down within one minute under the condition of a DC withstand voltage of 5000 V, and the coupling loss is greater than or equal to -70 dB at 0.5 meters. It can be seen that the leaky coaxial cable in this embodiment has good practicality.

[0035] Embodiment 2

[0036] The present embodiment provides another leaky coaxial cable, whose overall diameter is smaller than that of the first embodiment, thereby making it have a wider range of applications. Specifically, the structural arrangement and connection relationship between the inner conductor 10, the outer conductor 30, the insulator 20 and the sheath 40 in the present embodiment are the same as those in the first embodiment, and no further details are given here. The difference between the two is that the inner conductor 10 in the present embodiment has a diameter of 3.55 mm, the outer diameter of the insulator 20 is 9.8 mm, and the thickness of the outer conductor 30 is 0.05 mm.

[0037] Embodiment 3

[0038] This embodiment provides a method for preparing a leaky coaxial cable, which is used to prepare the leaky coaxial cable described in Embodiment 1, and specifically comprises the following steps:

[0039] Step S1, preparing an inner conductor 10, wherein the inner conductor 10 extends a preset distance in one direction; specifically, in this embodiment, the inner conductor 10 is formed by twisting a plurality of copper wires together to form a strand.

[0040] Step S2, uniformly covering the inner conductor 10 with an insulator 20;

[0041] Step S3, continuously winding the strip-shaped flexible copper foil in a spiral manner on the outside of the insulator 20 to form an outer conductor 30; the flexible copper foils of adjacent turns overlap by a preset length, and the preset length satisfies: when the bending radius of the leaky coaxial cable is greater than or equal to a preset value, the flexible copper foils of adjacent turns remain in an overlapping state; when the bending radius of the leaky coaxial cable is less than a preset value, the flexible copper foils of adjacent turns are separated from each other to form a gap 50;

[0042] Step S4 , coating the outer conductor 30 with a layer of protective material to form a sheath 40 .

[0043] Embodiment 4

[0044] This embodiment provides an application method of a leaky coaxial cable, which includes the following steps:

[0045] Step a, determining signal coverage requirements, determining the location on the leaky coaxial cable where signal leakage is required;

[0046] Step b, bend the position where the signal leakage is required on the leaky coaxial cable, with a bending radius less than the preset value, so that the flexible copper foils of adjacent circles at the corresponding position are separated from each other to form a gap 50. Furthermore, the bending radius in this embodiment is determined according to the strength required for actual signal coverage.

[0047] In summary, the leaky coaxial cable and its preparation and application methods described in the present invention can be applied to scenarios where signal coverage is required or not required. In areas where signal coverage is not required, it can be used as a feeder to perform conventional signal transmission operations. In areas where signal coverage is required, it can achieve adaptive signal coverage function by bending to change the overlapping state between adjacent turns of flexible copper foil of the outer conductor 30. In particular, the present application can independently select its signal coverage degree according to actual conditions. Based on this, compared with conventional leaky cables at this stage, the present application has the significant advantages of low loss, wide application range, strong controllability and high degree of adjustability, providing new ideas for the preparation and use of leaky cables.

[0048] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A leaky coaxial cable, characterized in that: include: An inner conductor (10) extending a preset distance in one direction; An insulator (20) wrapping the inner conductor (10); An outer conductor (30) is arranged on the outer surface of the insulator (20); the outer conductor (30) comprises a strip of flexible copper foil spirally and continuously wrapped around the insulator (20); adjacent turns of the flexible copper foil overlap by a preset length, and the preset length satisfies: when the bending radius of the leaky coaxial cable is greater than or equal to a preset value, the adjacent turns of the flexible copper foil remain in an overlapping state; when the bending radius of the leaky coaxial cable is less than the preset value, the adjacent turns of the flexible copper foil are separated from each other to form a gap (50); A sheath (40) wraps the outer conductor (30).

2. The leaky coaxial cable according to claim 1, characterized in that: The inner conductor (10) is formed by twisting a plurality of copper wires; the diameter of the inner conductor (10) is 3.55 mm-3.60 mm.

3. The leaky coaxial cable according to claim 1, characterized in that: The insulator (20) is made of foamed polyethylene material; the outer diameter of the insulator (20) is 9.8 mm-10.0 mm.

4. The leaky coaxial cable according to claim 1, characterized in that: The thickness of the outer conductor (30) is 0.05 mm-0.1 mm.

5. The leaky coaxial cable according to claim 1, characterized in that: The sheath (40) is a low-smoke, halogen-free, flame-retardant sheath.

6. The leaky coaxial cable according to claim 1, characterized in that: The single bending radius of the leaky coaxial cable is 35 mm; the multiple bending radius of the leaky coaxial cable is 70 mm.

7. A method for preparing a leaky coaxial cable, characterized in that: The following steps are involved: Step S1, preparing an inner conductor, wherein the inner conductor extends a preset distance in one direction; Step S2, uniformly covering the inner conductor (10) with an insulator (20); Step S3, continuously winding a strip of flexible copper foil in a spiral manner around the outside of the insulator (20) to form an outer conductor; adjacent turns of the flexible copper foil overlap by a preset length, and the preset length satisfies: when the bending radius of the leaky coaxial cable is greater than or equal to a preset value, the adjacent turns of the flexible copper foil remain in an overlapping state; when the bending radius of the leaky coaxial cable is less than the preset value, the adjacent turns of the flexible copper foil are separated from each other to form a gap (50); Step S4: coating the outer conductor (30) with a layer of protective material to form a sheath (40).

8. The method for preparing a leaky coaxial cable according to claim 7, characterized in that: The method for preparing the inner conductor comprises: In step S1, a plurality of copper wires are twisted together to form a strand.

9. The method for applying the leaky coaxial cable according to any one of claims 1 to 6, characterized in that: include: Step a, determining signal coverage requirements, determining the location on the leaky coaxial cable where signal leakage is required; Step b, bending the position on the leaky coaxial cable where signal leakage is required, with the bending radius being smaller than the preset value, so that adjacent turns of the flexible copper foil at the corresponding position are separated from each other to form a gap (50).

10. The application method according to claim 9, characterized in that: In step b, the bending radius is determined according to the strength required for signal coverage.

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