CN2859757Y

CN2859757Y - Leak coaxial cable

Info

Publication number: CN2859757Y
Application number: CNU2005200467829U
Authority: CN
Inventors: 姜耀鹏
Original assignee: CETC 23 Research Institute
Current assignee: CETC 23 Research Institute
Priority date: 2005-11-22
Filing date: 2005-11-22
Publication date: 2007-01-17
Anticipated expiration: 2015-11-22

Abstract

The utility relates to cable field, especially a leaky coaxial cable. The present cable of the utility has novel slot opening structure which can meet the need of mobile communication, broaden the leaky coaxial cable frequency band, promote radiation field intensity stability and uniformity. It is characterized in that the slot opening is U-shaped, slot opening middle part is parallel to cable axle, and notch at slot opening two ends are orthogonal to cable axle. Adjacent slot openings face opposite direction, while its span m is 200+/-10mm. Slot length parallel to cable axle is 77+/-3mm . Slot breath t vertical to cable axle is 10+/-3 mm. Transverse notch breadth is 3.5+/-1 mm, longitudinal notch breath p is 13+/-1mm. Slot opening span is suitable so most wide working frequency band, strengthened radiation field intensity and less transmission attenuation is achieved.

Description

A kind of leaky coaxial cable

Technical field:

The utility model relates to cable, is specifically related to a kind of leaky coaxial cable.

Background technology:

Leaky coaxial cable is one of major part in the mobile communication system, and generally it is made up of four parts from inside to outside successively: an inner wire, an insulator, an outer conductor, an oversheath.Insulator is tightly around inner wire, and vertical the packing tightly of outer conductor pasted around the insulator outer conductor outer wrapping one deck sheath.Usually inner wire is bare copper tube or wrinkle copper pipe, and dielectric is the physical blowing polyethylene, and outer conductor is smooth or wrinkle copper pipe (Copper Foil) and smooth or wrinkle aluminium foil, also useful wrinkle copper pipe etc., and sheath is generally polyethylene or low smoke halogen-free flame-retardant polyolefin.

In order to receive electromagnetic wave to outside radiated electromagnetic wave or from the outside, the leaky cable outer conductor has a series of lines of rabbet joint or hole, therefore also is opening feed cable.To the terminal transmission time, the also signal of telecommunication that is transmitted to the radiation of cable surrounding space, and also receive the signal of telecommunication of surrounding space has the dual-use function of transmission line and antenna to the signal of telecommunication from input.

The flexibility that the mobile communication system of forming with transmitting station, mobile station (portable), antenna, leaky coaxial cable has the stability and the radio communication of communication.This communication mode has obtained extensive use in all trades and professions, particularly in the environment that radio wave is difficult to propagate or in the blind area, obtain pay attention to day by day and application especially, as the safety devices of underground railway, highway, high-speed railway, mine, high buildings and large mansions, undergrond street, underground parking, national defense resource, ammunition depot, weapon manufactory etc. all must realize by the mobile communication system that leaky coaxial cable is formed between fixing point and transfer point, transfer point and the transfer point writing to each other and automation is controlled.

The existing leaky coaxial cable that adopts in the mobile communication system, its outer conductor irradiation structure adopt skewed slot or on the wrinkle copper pipe hole milling, the operating frequency of this radiation slotted eye is 150MHz～450MHz, working band is very narrow, radiation field intensity is inhomogeneous, fluctuates up and down up to ± 10dB.The flume structure that now generally uses is Eight characters flume structure, referring to Fig. 1, this structure is because the slotted eye pitch is long, radiation angle requires at ± 35 °, excursion is very narrow, standing wave crest frequency (resonance frequency) is very approaching, makes that the frequency band that can work is very narrow, and radiation characteristic and transmission characteristic do not reach working band that current mobile communication proposes far away in (900～2400) MHz, radiation field intensity fluctuation high-quality requirement about ± 3dB.

It is as follows that existing flume structure can not reach the analysis of causes of defective of high-quality requirement:

At first, in order to reach certain radiation field intensity, the length of skewed slot is greater than 13cm usually, operating frequency according to 150MHz, 450MHz, the skewed slot pitch is chosen in about 150cm, under this physical dimension, if operating frequency is brought up to more than the 900MHz, then cable just can not be operated in single mould state, and becomes the multimode state, and at this moment the radiation angle of radiation field intensity no longer is desired ± 35 °, become more than 60 °, therefore radiation field becomes and rises and falls unstablely, and fluctuation will arrive greatly ± and more than the 10dB, this is the major defect of flume structure.If change the fluting pitch, pitch is reduced to 53cm, and (during operating frequency 900MHz, pitch is just at 53cm, 30 ° of radiation angles) below, for guaranteeing that enough radiation field intensities are arranged, the flute length of skewed slot can not reduce, so just bring technologic difficulty, the lapping problem of the adjacent line of rabbet joint can occur.

On the other hand, though the radiation field intensity of flume structure is the transverse field based on perpendicular polarization, also have the radiation level polarization to be parallel to the longitudinal field of cable axle simultaneously, this is unwanted an of mobile communication.Because the effect of the longitudinal field that horizontal polarization produces by surrounding environment (wall, metal object etc.) and the transverse field mutual superposition of perpendicular polarization upset the transverse field of the needed perpendicular polarization of communicating by letter, make that the transverse field fluctuation of perpendicular polarization is unstable, amplitude variations is very big, and this also is the problem place that the working band of flume structure is difficult to widen.

Summary of the invention:

Technical problem to be solved in the utility model provides a kind of leaky coaxial cable, and it has new slot structure, can adapt to the requirement of present mobile communication, can widen the frequency band of leaky coaxial cable, improves the stability and the uniformity of radiation field intensity.

For solving the problems of the technologies described above, the utility model is to propose following technical scheme to realize:

A kind of leaky coaxial cable, interior to being made up of inner wire, insulator, outer conductor, oversheath successively outward, axially spaced-apart evenly has one group of line of rabbet joint of the same size on the described outer conductor; It is characterized in that: the described line of rabbet joint is " U " font, line of rabbet joint middle part is parallel with the cable axle, line of rabbet joint two ends notch is vertical with the cable axle, the adjacent line of rabbet joint is towards on the contrary, pitch m is 200 ± 10mm, and the line of rabbet joint flute length l parallel with the cable axle is 77 ± 3mm, and the groove width t that the line of rabbet joint is vertical with the cable axle is 10 ± 3mm, transverse notch width h is 3.5 ± 1mm, and vertically width of rebate p is 13 ± 1mm.

The utility model brings following beneficial effect:

1. novel, that unique line of rabbet joint shape is embodied in line of rabbet joint vertical-rise cable shaft portion is very short, and the part of parallel cable axle is longer relatively, narrower in width, because such slot structure, make it possible to both guarantee the requirement of amount of radiation, guaranteed well that again the original transmission characteristic of cable can not be affected because of the existence of the line of rabbet joint simultaneously.

2. the part of line of rabbet joint middle part parallel cable axle is very narrow, adjacent " coupling aperture " reverse configuration, can make the longitudinal field of horizontal polarization drop to minimum, the back reflective that comes that can eliminate owing to the longitudinal field of horizontal polarization reverses the transverse field of perpendicular polarization, and makes the transverse field phase mutual interference of original perpendicular polarization and destroyed the stability and the inhomogeneity problem of the transverse field of perpendicular polarization.

3. the mutual arrangement of the line of rabbet joint is the most reasonable, combination the most cleverly, the adjacent line of rabbet joint forms one positive one anti-" coupling aperture ", make the transverse field (needed of mobile communication) of perpendicular polarization obtain strengthening to greatest extent, curb simultaneously the longitudinal field of horizontal polarization again, make radiance subtract and drop to minimum, coupling loss and transmission attenuation also drop to minimum thereupon.Just for the leaky coaxial cable of same size, this structure is wideer than other arrangement works frequency bands, and radiation field intensity is stronger, the reason that transmission attenuation is littler.

4. the pitch design owing to the line of rabbet joint gets the very suitable requirement that adapts to present mobile communication, can widen the frequency band of leaky coaxial cable.

Description of drawings:

Fig. 1: the flume structure schematic diagram of existing leaky coaxial cable

Fig. 2: the slot structure schematic diagram of the utility model embodiment

Fig. 3: the enlarged diagram of the line of rabbet joint A of the utility model embodiment

Embodiment:

Below in conjunction with the drawings and specific embodiments the utility model is described further:

It is wide that a kind of slot structure of the best must embody working band, reach (900～2400) MHz or higher, radiation field intensity is uniform and stable, fluctuation range about ± (3～5) dB, radiation characteristic and transmission characteristic are all very excellent.

In the present embodiment, the outer conductor material therefor is the copper belt that 0.12mm is thick, 150mm is wide, axially spaced-apart evenly has one group of line of rabbet joint of the same size on the outer conductor, the line of rabbet joint is " U " font, line of rabbet joint middle part is parallel with the cable axle, line of rabbet joint two ends notch is vertical with the cable axle, the adjacent line of rabbet joint is towards on the contrary, pitch m is 200mm, the line of rabbet joint flute length l parallel with the cable axle is 77 ± 0.1mm, the groove width t that the line of rabbet joint is vertical with the cable axle is 10 ± 0.05mm, and transverse notch width h is 3.5 ± 0.05mm, and vertically width of rebate p is 13 ± 0.05mm.

Below in conjunction with Fig. 2, the important feature of the utility model embodiment is described:

1, about pitch " m "

Reaching above-mentioned requirements, be key parameter for the leaky coaxial cable outer conductor in the pitch of the line of rabbet joint, and pitch determines radiation angle.Pitch must be enough little, makes the radiation angle of line of rabbet joint radiation field can adhere to operating frequency and change in a suitable and bigger scope, thereby obtain broad working band.

The spacing that skewed slot has been described in the background technology of front can not be done very for a short time, and the utility model has adopted the method for transversal slotting, and just the line of rabbet joint and cable axle are parallel to each other, accumbency is seen Fig. 2 on outer conductor, arrange like this, can be closer apart between groove and the groove, and can not interact.This be the most novel, the most reasonable at present also be state-of-the-art a kind of alignment arrangements method.See that from Fig. 2 landscape configuration makes each line of rabbet joint both can independently lay, can suffer very closely again mutually that the spacing of the adjacent like this line of rabbet joint just can be done as much as possible for a short time.

2, about line of rabbet joint length " l "

The size of line of rabbet joint length decision radiation field intensity, in order to obtain desirable amount of radiation from each line of rabbet joint is by controlling the selection of line of rabbet joint length " l ", i.e. control passes that the lateral displacement electric current of the line of rabbet joint realizes, also controls along the radiance of cable length direction signal simultaneously in this to subtract.

3, about the width " t " of the line of rabbet joint

The width of the line of rabbet joint " t " will design enough narrowly, makes the cross-polarized amount of radiation of the line of rabbet joint reach minimum.

If the broadening working band, under the situation that keeps single wave beam operating state, the spacing and the line of rabbet joint length that only need suitably reduce the adjacent line of rabbet joint can obtain wideer working band.

4, about " coupling aperture "

In order to go out the transverse field of the opposite perpendicular polarization of both direction from the cable inner couplings, an edge along the line of rabbet joint, and one of design right in the middle " coupling aperture " on one side of the line of rabbet joint, see Fig. 2, " coupling aperture " of adjacent slot is configured in rightabout, and what this " coupling aperture " must be enough is narrow, the radiation angle of radiation field is littler with frequency change like this, help the fixed location received signal, also enlarge the working range of single wave beam simultaneously, make working band wideer.

Adjacent slot " coupling aperture " another benefit of configuration in the other direction is to make to cancel out each other along the horizontal direction radiation field of cable axle, thereby eliminates along the axial radiation loss of cable.

Present embodiment is owing to the pitch design of the line of rabbet joint gets the very suitable the wideest working band that obtained, and the working band of this structure can reach (900～2400) MHz, and this is the most outstanding advantage of this structure.And cable is compared with the perpendicular polarization field along the cross-polarization field and is wanted little 15dB, therefore coupling loss is stably arranged in the passband scope, obtains even, smooth perpendicular polarization field along the cable length direction.All about ± (3～5) dB, this is most important to high quality communication, particularly to Digital Transmission, can reach 10 for their fluctuation range ^-8The requirement of the error rate, be used for the distortion of analog communication signal, distortion all seldom.

Claims

1. leaky coaxial cable, interior to being made up of inner wire, insulator, outer conductor, oversheath successively outward, axially spaced-apart evenly has one group of line of rabbet joint of the same size on the described outer conductor; It is characterized in that: the described line of rabbet joint is " U " font, line of rabbet joint middle part is parallel with the cable axle, line of rabbet joint two ends notch is vertical with the cable axle, the adjacent line of rabbet joint is towards on the contrary, pitch (m) is 200 ± 10mm, and the line of rabbet joint flute length (1) parallel with the cable axle is 77 ± 3mm, and the groove width that the line of rabbet joint is vertical with the cable axle (t) is 10 ± 3mm, transverse notch width (h) is 3.5 ± 1mm, and vertically width of rebate (p) is 13 ± 1mm.