WO2018121339A1 - Bending-resistant broadband radiant-type leaky coaxial cable - Google Patents

Abstract

A bending-resistant broadband radiant-type leaky coaxial cable, comprising an inner conductor (1) extending in an axial direction, and an insulator (2), an outer conductor (3) and an outer sheath (4) arranged outside the inner conductor in sequence from inside to outside; the inner conductor is a spiral corrugated copper tube; the outer conductor closely coats the insulator, and is periodically provided with slots (5) in the axial direction; knurls (6) having V-shaped cross sections are provided on the outer surface of the outer conductor. In the cable, a spiral corrugated copper tube is used as the inner conductor, and V-shaped knurls are formed on the outer surface of the outer conductor by pressing with a knurling apparatus, so that the cable has good bending resistance. In addition, the leaky coaxial cable is applicable to a wider band, and a copper strip used as the outer conductor is continuous, uniform and defect-free, so that controlled electromagnetic wave energy can be evenly radiated and received along a line to cover a blind area of an electromagnetic field, and therefore, smooth mobile communication is achieved.

Description

Curved broadband radiation type leaky coaxial cable Technical field

The present application belongs to the technical field of transmission cable design and manufacture, and in particular relates to a bending-resistant broadband radiation type leaky coaxial cable.

Background technique

With the rapid development of mobile communications and the proliferation of densely built high-rise buildings and underground facilities, the interior absorbs most of the traffic. The coverage of the outdoor macrocell base station alone cannot meet the requirements of network coverage, capacity and quality. Emerging leaky cable technology has been widely used in high-speed rail and urban subways. For the existing wireless communication system, its excellent broadband capability can meet the needs of multi-system access. In the process of indoor coverage, especially in the flat layout of high-rise buildings, the bending resistance of leaky coaxial cables is of great significance. In the prior art, the conventional leaky coaxial cable has a large bending radius, which is disadvantageous for the indoor layout.

Application content

In view of this, the present application aims to propose a bending-resistant broadband radiation type leaky coaxial cable, which has good bending performance, and is of great value for the application of the cable to the indoor coverage scene.

In order to achieve the above object, the technical solution of the present application is implemented as follows:

A bending-resistant broadband radiation type leaky coaxial cable comprising an inner conductor extending in the axial direction, and an insulator, an outer conductor and an outer sheath disposed from the inside to the outside of the inner conductor; the inner conductor adopts a spiral wrinkle copper a tube; the outer conductor is tightly coated on the insulator, and is periodically slotted in the axial direction, and has a V-shaped cross section on the outer surface thereof.

Further, the insulator is a continuous foamed polyethylene insulation layer concentrically wrapped around the inner conductor.

Further, the insulator has a nominal diameter of 22 mm.

Further, the slotted holes in the insulator are a plurality of groups arranged at equal intervals, and each group includes two slots correspondingly disposed, and the two form a figure-eight structure.

Further, the inner diameter of the spiral corrugated copper tube used in the inner conductor is 7.60 mm ± 0.30 mm.

Further, the spiral wrinkle copper tube used in the inner conductor has an outer diameter of 9.40 ± 0.20 mm and an outer diameter of the valley of 7.30 ± 0.30 mm.

Compared with the prior art, the present application has the following advantages:

The present application adopts a spiral corrugated copper tube as an inner conductor, and at the same time, the outer surface of the outer conductor is pressed into a V-shaped roll by a roll fabric device, so that the cable itself has good bending resistance. In addition, the leaky coaxial cable is applied to a wider frequency band, and the copper strip as the outer conductor is continuous, uniform, and free from defects, and the controlled electromagnetic wave energy can be radiated and received uniformly along the line to achieve coverage of the electromagnetic field blind zone. In order to achieve the purpose of smooth mobile communication.

DRAWINGS

The accompanying drawings, which are incorporated in the claims of the claims In the drawing:

Figure 1 is a schematic view of the structure of the present application.

Description of the reference signs:

1-inner conductor; 2-insulator; 3-outer conductor; 4-outer sheath; 5-slot; 6-roll.

detailed description

It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict.

In the description of the present application, it is to be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", " The orientation or positional relationship of the indications of "upright", "horizontal", "top", "bottom", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings, only for the convenience of describing the present application and The simplification of the description is not intended to be a limitation or a limitation of the invention. Moreover, the terms "first", "second", and the like are used for the purpose of description only, and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first", "second", etc. may include one or more of the features, either explicitly or implicitly. In the description of the present application, "a plurality" means two or more unless otherwise stated.

In the description of the present application, it should be noted that the terms "installation", "connected", and "connected" are to be understood broadly, and may be fixed or detachable, for example, unless otherwise specifically defined and defined. Connected, or integrally connected; can be mechanical or electrical; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of the two components. The specific meanings of the above terms in the present application can be understood by a person of ordinary skill in the art.

The present application will be described in detail below with reference to the accompanying drawings.

A bending-resistant broadband radiation type leaky coaxial cable, as shown in FIG. 1, includes an inner conductor 1 extending in the axial direction, and an insulator 2, an outer conductor 3 and an outer sheath which are disposed in order from the inside to the outside of the inner conductor 1 4; the inner conductor 1 is a spiral corrugated copper tube; the outer conductor 3 is tightly coated on the insulator 2, which periodically slots the hole 5 in the axial direction, and has a cross section on the outer surface thereof. V-shaped roll 6.

The outer conductor 3 is formed by longitudinally lap-bonding of copper strips. The material of the copper strip should be uniform, the thickness is uniform, the surface is smooth and flat without defects, and the outer conductor copper strip should be continuous, free of oil, and free of defects such as oxidation. In order to ensure the low attenuation of the leaky coaxial cable, low voltage standing wave ratio and strong environmental adaptability.

The leaky coaxial cable is applicable to a wider frequency band, and has both a signal transmission function and an antenna function. The copper strip as the outer conductor is continuous, uniform, and free from defects, and the controlled electromagnetic wave energy can be radiated uniformly along the line. Received in, to achieve coverage of the electromagnetic field blind zone, in order to achieve the purpose of mobile communication.

The outer conductor has a periodic slot structure with the characteristic of radiating electromagnetic waves outward. In addition, the outer conductor copper strip is pressed by the V-shaped corrugated fabric by the roller device, the corrugation pitch is 0.5-2.0 mm, and the embossing depth is 0.2-1.0 mm, which obviously improves the bending performance of the cable.

It should be noted that the spiral corrugated copper tube weld used in the inner conductor 1 is continuous, smooth, and has no pinhole defects; the insulator 2 is made by mixing different density polyethylene insulation materials and a small amount of nucleating agent in an appropriate ratio. Insulation grade polyethylene insulation blend. The insulator is prepared by physical foaming of carbon dioxide or nitrogen. After a certain proportion of various polyethylene insulating materials are uniformly mixed, it is heated and melted in an extruder, and high-purity carbon dioxide or nitrogen is injected into the molten insulator through a syringe in a high-pressure form to be thoroughly mixed. The foamed insulator is formed by extrusion through a handpiece.

Wherein, the insulator 2 is a continuous foamed polyethylene insulation layer concentrically wrapped around the inner conductor. The nominal diameter of the above insulator is preferably taken to be 22 mm. Compared with the traditional air-insulated structure, the transmission parameters such as characteristic impedance, VSWR, coupling loss and longitudinal attenuation are more uniform and stable, and it can resist the intrusion of moisture into the cable in a humid environment, and prevent the transmission performance from being damaged by moisture or Loss, greatly improving the service life and stability.

The slots 5 formed in the insulator 2 are a plurality of groups arranged at equal intervals, and each group includes two slots correspondingly disposed, and the two form a figure-eight structure. It should be noted that the outer conductor copper strip is provided with periodically arranged slots having a pitch corresponding to the wavelength of the use frequency. There is no resonance point, and the coupling loss of 50% of the same frequency is less than 5dB with the coupling loss of 95%, thereby greatly improving the quality of the communication signal and satisfying the signal transmission of the broadband communication system of 2G, 3G and 4G.

The inner conductor copper tube spiral wrinkle structure is rolled by a welding embossing production equipment. The inner conductor of the spiral corrugated copper tube is formed by longitudinally forming a copper strip, welding, spiral embossing or spiral embossing of a copper tube. The peak outer diameter is 9.40±0.20 mm, the outer diameter of the trough is 7.30±0.30 mm, the spiral wrinkle pitch is 7.60±0.30 mm, and the minimum thickness of the tube wall before embossing is 0.21 mm.

The outer sheath 4 is preferably made of a black polyethylene sheath or a low-smoke halogen-free flame-retardant polyolefin sheath, which has better waterproof and fireproof performance, makes the use of the cable safer, and adopts a suitable polyethylene sheath to ensure the cable itself. Less interfered by the external environment. If necessary, in an alternative embodiment, the outer sheath may be an inner layer and an outer layer double-layer structure, and an ointment is applied between them to ensure that the external force is pressed and impacted when used or laid. .

For a conventional radiant leaky coaxial cable with a nominal outer diameter of 22 mm, the inner conductor structure is of a smooth copper tube type. The radiation-type leaky coaxial cable with an insulation nominal outer diameter of 22 mm as described in the application has an inner conductor structure of a spiral corrugated copper tube structure. The latter has better bending resistance due to the different inner conductor structure.

The following are two types of leaky coaxial cables with a nominal diameter of 22 mm and a comparison of the bending properties of the inner conductor structure of the smooth copper tube and the inner conductor structure of the spiral corrugated copper tube.

As can be seen from the comparison of the above table, since the inner conductor is a spiral corrugated copper tube structure, the bending resistance of the leaky coaxial cable is remarkably improved.

The present application adopts a spiral corrugated copper tube as an inner conductor, and at the same time, the outer surface of the outer conductor is pressed into a V-shaped roll by a roll fabric device, so that the cable itself has good bending resistance. In addition, the leaky coaxial cable is applied to a wider frequency band, and the copper strip as the outer conductor is continuous, uniform, and free from defects, and the controlled electromagnetic wave energy can be radiated and received uniformly along the line to achieve coverage of the electromagnetic field blind zone. In order to achieve the purpose of smooth mobile communication.

The above description is only for the preferred embodiment of the present application, and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application are included in the present application. Within the scope of protection.

Claims (6)

1. A bending-resistant wide-band radiation type leaky coaxial cable, comprising: an inner conductor extending in the axial direction; and an insulator, an outer conductor and an outer sheath arranged in sequence from the inside to the outside of the inner conductor; wherein the inner conductor is a spiral corrugated copper tube; the outer conductor is tightly coated on the insulator, which periodically slots the hole in the axial direction, and is provided on its outer surface with a V-shaped cross section.
2. A bend-resistant broadband radiation leaky coaxial cable according to claim 1, wherein said insulator is a continuous foamed polyethylene insulation layer concentrically wrapped around said inner conductor.
3. A bending-resistant broadband radiation type leaky coaxial cable according to claim 1 or 2, wherein said insulator has a nominal diameter of 22 mm.
4. A bending-resistant broadband radiation type leaky coaxial cable according to claim 1, wherein the slotted holes in the insulator are a plurality of groups arranged at equal intervals, and each group includes two slots correspondingly disposed. The two form a figure-eight structure.
5. A bending-resistant broadband radiation-type leaky coaxial cable according to claim 1, wherein said inner conductor has a spiral corrugated copper tube having a pitch of 7.60 mm ± 0.30 mm.
6. A bending-resistant broadband radiation type leaky coaxial cable according to claim 1 or 5, wherein the outer diameter of the spiral wrinkle copper tube used in the inner conductor is 9.40 ± 0.20 mm, and the outer diameter of the valley It is 7.30 ± 0.30 mm.