Leaky coaxial cable for indoor distribution and method and system for designing same

Abstract

The application discloses an indoor distribution leaky coaxial cable and a design method and system thereof, and belongs to the technical field of communication cables. The design method comprises the following steps: according to the position of the electromagnetic wave target coverage area of a target scene space, designing different electromagnetic wave radiation direction angles of the leaky coaxial cable along a line; according to the designed different electromagnetic wave radiation direction angles of the leaky coaxial cable along the line, calculating different pitches of slot hole periodicity corresponding to the different electromagnetic wave radiation direction angles of the leaky coaxial cable; according to the designed different electromagnetic wave radiation direction angles and the calculated different pitches of slot hole periodicity corresponding thereto, and combining the requirement that the electromagnetic wave radiation intensity of the target coverage area is consistent, calculating the slot length of the slot hole in each pitch of the leaky coaxial cable. The application can guarantee that the leaky coaxial cable neither has an obvious weak coverage area on the target coverage area nor excessively overlaps with outdoor signals, so as to achieve the purpose of optimizing the indoor distribution coverage effect of the leaky coaxial cable.

Description

Technical Field

[0001] This invention belongs to the field of communication cable technology, and specifically relates to a leaky coaxial cable for indoor distribution and its design method and system. Background Technology

[0002] Leaky coaxial cable is a type of communication cable that can be used for both signal transmission and reception, and it is widely used in indoor distribution systems. For example... Figure 1 As shown, the leaky coaxial cable consists of an inner conductor 1, a foamed insulation layer 2, an outer conductor 4 with slots 3, and a sheath layer 5. Signal transmission and reception are achieved through the slots 3 on the outer conductor. In an indoor distribution system, the leaky cable covers the center of the target coverage area, and good signal coverage can be achieved along the route of the leaky coaxial cable.

[0003] In current wireless communication system coverage schemes, outdoor spaces are primarily covered by external base stations for wide-area coverage. However, due to building obstructions and other environmental factors, many indoor locations are not covered by outdoor signals. Existing indoor signal coverage mainly relies on leaky coaxial cables or indoor distributed antennas. Signals are routed from the equipment room, and the leaky coaxial cables or antennas provide wireless signal coverage for indoor areas. Leaky coaxial cables are widely used in indoor distribution systems, such as... Figure 2 As shown, commonly used leaky coaxial cables have electromagnetic signals with a consistent radiation direction (same angle θ) in a specific frequency band. However, there is still strong outdoor signal coverage in an area of ​​about one meter inside the windowsill of various buildings. This results in cross coverage of indoor and outdoor signals in areas such as the windowsill, while the signal is weaker near the corner of the wall.

[0004] Based on this, the present invention proposes a design method for leaky coaxial cables for indoor distribution, which ensures more adequate indoor signal coverage and avoids cross-over or weak signal coverage. Summary of the Invention

[0005] The main objective of this invention is to provide a leaky coaxial cable for indoor distribution, as well as its design method and system. By designing a combination of external radiating units of leaky coaxial cables with different slot sizes and slot pitches, the electromagnetic wave radiation direction of each radiating unit with different slot sizes and pitches can be aligned with the target coverage area, and the level of the radiated signal (i.e., coupling loss) within the target coverage area tends to be consistent, thereby optimizing the performance of the leaky coaxial cable in the indoor target coverage area.

[0006] To achieve the above objectives, the present invention provides a design method for a leaky coaxial cable for indoor distribution, comprising the following steps: Step S1: Based on the location of the electromagnetic wave target coverage area in the target scene space, design different electromagnetic wave radiation direction angles along the leaky coaxial cable. Step S2: Based on the different electromagnetic wave radiation direction angles along the leaky coaxial cable designed in Step S1, calculate the periodic pitch of the slots corresponding to the different electromagnetic wave radiation direction angles of the leaky coaxial cable. Step S3: Based on the different electromagnetic radiation direction angles designed in Step S1 and the different periodic pitches of the corresponding slots calculated in Step S2, and in combination with the requirement that the electromagnetic radiation intensity of the target coverage area is consistent, calculate the slot length of each pitch of the leaky coaxial cable.

[0007] Furthermore, in step S2, the formula for calculating the different pitches of the slot periodicity under different electromagnetic wave radiation direction angles is as follows: Formula 1; in, The equivalent dielectric constant of the insulation medium of the leaking coaxial cable; The wavelength is the frequency corresponding to the electromagnetic wave. To prevent leakage of the pitch between the coaxial cable slots; The angle between the electromagnetic radiation direction of the leaky coaxial cable and the transmission direction of the leaky coaxial cable.

[0008] Furthermore, in step S3, the formula for calculating the slot length of the slot in each pitch of the leaking coaxial cable is as follows: Formula 2; in, The leakage attenuation of the nth pitch segment of the coaxial cable is a constant; B is a fixed coefficient, also a constant; P n The nth segment pitch length between the slots of the leaky coaxial cable; θ n L is the angle between the electromagnetic radiation direction and the transmission direction of the leaky coaxial cable at the nth pitch length; n The slot length of the leaky coaxial cable is the length of the nth pitch segment.

[0009] Furthermore, in step S1, the angles of different electromagnetic wave radiation directions along the leaky coaxial cable are designed to be θ1 to θ2. n , and θ1 to θ n All intermediate values ​​should satisfy or (1≤x≤n); Where θ1 is the electromagnetic radiation angle of the leaky coaxial cable at the initial pitch along the transmission direction, θ n The angle of electromagnetic wave radiation at the last pitch of the coaxial cable along the transmission direction; When the length of the leaky coaxial cable is greater than the length of the first and last ends of the covered area, θ1≤θ nWhen the length of the leaky coaxial cable is less than the length of the first and last ends of the covered area, θ1 ≥ θ n ; The electromagnetic radiation direction angle is defined as the angle between the direction of the strongest electromagnetic wave amplitude in the electromagnetic radiation lobe diagram of the leaky coaxial cable and the transmission direction of the leaky coaxial cable.

[0010] Further, in step S1, based on the location of the electromagnetic wave target coverage area in the target scene space, the different electromagnetic wave radiation direction angles along the leaky coaxial cable are designed, including: Based on the initial and final boundaries of the electromagnetic wave target coverage area in the target scene space, and the initial and final boundary positions of the leaky coaxial cable, the slot radiation angle boundary values ​​θ1 and θ2 at the starting and ending positions of the leaky coaxial cable are calculated. n ; The angles of the electromagnetic radiation direction in the middle section of the leaky coaxial cable are treated as equal arithmetic steps, i.e., from θ1 to θ... n It is an arithmetic sequence, where θ1 to θ n The number of leaky coaxial cable structures, n, is gradually increased or decreased based on θ1 to θ2. n The tolerance is determined by the choice of the arithmetic sequence |θ n -θ n-1 |≥3°.

[0011] The present invention also provides an indoor distribution leaky coaxial cable designed using the aforementioned leaky coaxial cable design method. The leaky coaxial cable includes, from the inside out, an inner conductor, an insulation layer, an outer conductor, and a sheath layer. The outer conductor has periodic slots with different pitch intervals distributed along its axis. Each pitch of the leaky coaxial cable has the same coupling loss.

[0012] Furthermore, the slot width W of the leaky coaxial cable is consistent, and the slot width is 1 / 8 to 1 / 10 of the average slot length of multiple pitch structure slots.

[0013] The present invention also provides a design system for leaky coaxial cables for indoor distribution, comprising: The electromagnetic wave radiation direction design module is configured to design different electromagnetic wave radiation direction angles along the leaky coaxial cable based on the location of the electromagnetic wave target coverage area in the target scene space. The slot pitch estimation module is configured to estimate the periodic different pitches of the slots of the leaky coaxial cable at different electromagnetic radiation direction angles along the line designed by the electromagnetic radiation direction design module. The slot length estimation module is configured to estimate the slot length of each segment of the leaky coaxial cable based on the different electromagnetic radiation direction angles designed by the electromagnetic radiation direction design module and the periodic different pitches of the corresponding slots estimated by the slot pitch estimation module, and in combination with the requirement that the electromagnetic radiation intensity of the target coverage area is consistent.

[0014] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the program to implement the steps of the aforementioned design method for a leaky coaxial cable for indoor distribution.

[0015] The present invention also provides a computer-readable storage medium having a computer program stored thereon, characterized in that the computer-readable storage medium has a computer program stored thereon, and the computer program, when run by a processor, performs the steps of the aforementioned design method for a leaky coaxial cable.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) Based on the radiation theory of the radial leaky coaxial cable, the present invention designs different radiation directions along the line of the leaky coaxial cable according to the coverage area location of different scene spaces, and configures the pitch of the outer guide slot according to the radiation direction, so that the electromagnetic wave signal radiated by the leaky coaxial cable can fully cover the target coverage area in the indoor distribution scene, and can concentrate on covering a specific area.

[0017] (2) According to the pitch between slots and the preset electromagnetic wave radiation direction of the slots, the present invention sets the matching slot leakage radiation amount according to a specific formula relationship along the leaky coaxial cable, so that the slot length of the leaky coaxial cable along the line satisfies Formula 2, so that the leaky coaxial cable along the line has consistent coupling loss.

[0018] (3) After design and calculation, the leaky coaxial cable of the present invention adopts the same type of outer conductor slot combination and is manufactured according to the design length. Finally, a customized product with several different slot pitches and slot lengths on a section of leaky coaxial cable is produced. Its performance can ensure that the leaky coaxial cable does not have obvious weak coverage areas in the target coverage area, nor does it overlap too much with outdoor signals. The radiated signal is concentrated in a certain area of ​​the target coverage area to a certain extent, so as to achieve the purpose of optimizing the indoor coverage effect of the leaky coaxial cable. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of an existing leaky coaxial cable. Figure 2 This is a schematic diagram showing the electromagnetic wave radiation to the target radiation area under the typical conditions of an existing leaky coaxial cable. Figure 3 A schematic diagram of the outer conductor slot structure of a commonly used leaky coaxial cable; Figure 4 This is a flowchart illustrating the design method of the leaky coaxial cable for indoor distribution according to the present invention. Figure 5 A schematic diagram showing the radiation direction of a leaky coaxial cable slot. Figure 6 A schematic diagram showing the adjustment of the electromagnetic wave radiation direction of the leaky coaxial cable designed for this invention to the target area; Figure 7 Radiation lobe diagram of a leaky coaxial cable; Figure 8 This is a schematic diagram of the external guide slot structure of a leaky coaxial cable, which is an example of the present invention.

[0020] The above-mentioned figures include the following reference numerals: 1, inner conductor; 2, foamed insulation layer; 3, slot; 4, outer conductor; 5, sheath layer. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] Radial leaky coaxial cable is a coaxial cable with periodic slots on its outer conductor. Common slot arrangements include... Figure 3 As shown, based on these arrangements, the slots in a leaky coaxial cable can emit radiated waves with a wide frequency range. Radiation-type leaky coaxial cables couple a portion of the internal energy outwards through the slots. When the slot pitch and signal frequency meet certain conditions, the leaky coaxial cable emits radiated waves at a specific angle. Conventional leaky coaxial cables use a completely uniform external conductor slot structure, resulting in completely uniform electromagnetic wave radiation direction and intensity at specific frequency bands, leading to signal overlap or weak coverage issues.

[0023] To address the above problems, this invention proposes a design method for leaky coaxial cables used in indoor distribution, such as... Figure 4 As shown, it includes the following steps: Step S1: Based on the location of the electromagnetic wave target coverage area in the target scene space, design different electromagnetic wave radiation direction angles along the leaky coaxial cable. Step S2: Based on the different electromagnetic wave radiation direction angles along the leaky coaxial cable designed in Step S1, calculate the periodic pitch of the slots corresponding to the different electromagnetic wave radiation direction angles of the leaky coaxial cable. Step S3: Based on the different electromagnetic radiation direction angles designed in Step S1 and the different periodic pitches of the corresponding slots calculated in Step S2, and in combination with the requirement that the electromagnetic radiation intensity of the target coverage area is consistent, calculate the slot length of each pitch of the leaky coaxial cable.

[0024] Under typical conditions where radiating leaky coaxial cables operate in their optimal frequency band (i.e., without considering the radiation of higher-order mode electromagnetic waves; radiating leaky coaxial cables usually utilize only single-mode radiation for wireless communication in engineering to ensure transmission quality), the angle θ between the electromagnetic wave radiation direction and the transmission direction of the leaky coaxial cable (e.g., ...) Figure 5 ) can be obtained from The relationship is derived from this, where, To leak the longitudinal propagation constant of electromagnetic waves on a coaxial cable, is the propagation constant of electromagnetic waves in space. The equivalent dielectric constant of the insulation medium of the leaking coaxial cable; The wavelength is the frequency corresponding to the electromagnetic wave. The pitch between the slots of the leaky coaxial cable is given. Based on the above relationship, the periodic pitch of each slot in the leaky coaxial cable can be calculated using the following formula 1.

[0025] Formula 1; in, The equivalent dielectric constant of the insulation medium of the leaking coaxial cable; The wavelength is the frequency corresponding to the electromagnetic wave. To prevent leakage of the pitch between the coaxial cable slots; The angle between the electromagnetic radiation direction of the leaky coaxial cable and the transmission direction of the leaky coaxial cable.

[0026] For example, such as Figure 6 As shown, the leaky cable of this invention radiates electromagnetic waves towards the target coverage area. The direction of electromagnetic wave radiation is defined as the direction with the strongest electromagnetic wave amplitude in the electromagnetic wave radiation lobe diagram. There are still some weaker signals in other directions (when the radial leaky coaxial cable operates at its optimal operating frequency, the multimode signal, i.e., the electromagnetic waves in other directions, is suppressed by the slot arrangement, allowing the leaky coaxial cable to radiate a stronger electromagnetic wave in a certain direction in a single mode). Its electromagnetic wave lobe diagram is shown below. Figure 7 As shown, Figure 7 The layered, petal-like structure in the middle represents the electromagnetic waves of each mode in the leaky coaxial cable. The leaky coaxial cable of this invention only considers the electromagnetic waves in the strongest direction, with the electromagnetic wave radiation direction varying from θ1 to θ...n The selected leaky cable can be in sizes from 1 / 2" to 1-5 / 8", and its dielectric equivalent dielectric constant is [not specified]. It is generally between 1.2 and 1.4.

[0027] Electromagnetic radiation range of leaky coaxial cable (θ1, θ) n The value of θ can be calculated based on the actual dimensions and requirements of the site. Substituting the θ value into Formula 1, the range of periodic pitch P of the outer conductor slot of the leaky coaxial cable at a specific operating frequency wavelength λ can be calculated, and θ1 to θ n All intermediate values ​​should satisfy θ1≤θ x ≤θ n or θ1≥θ x ≥θ n (1≤x≤n) to avoid weak coverage areas in the coaxial cable coverage space. For example... For a 1-1 / 4" leaky cable with a diameter of 1.23, the main electromagnetic radiation direction in the 2100MHz operating frequency band is as follows: Figure 5 The preset angle is 88° to 104°, so the pitch value range for leaky coaxial cable design is 105.6mm to 132.7mm.

[0028] For example, the design of different electromagnetic wave radiation direction angles along the leaky coaxial cable involves: based on the initial and final boundaries of the electromagnetic wave coverage area of ​​the target scene space, and the initial and final boundary positions of the leaky coaxial cable, calculating the slot radiation angle boundary values ​​θ1 and θ2 at the beginning and end positions of the leaky coaxial cable. n The radiation direction of the middle section of a leaky coaxial cable should be uniformly directed towards the coverage area; therefore, for a change from θ1 to θ... n The angle change of each segment of the slot is treated as an arithmetic progression, i.e., from θ1 to θ... n It is an arithmetic sequence, from θ1 to θ n By gradually increasing or decreasing the number of leaky coaxial cables, a more uniform electromagnetic coverage can be ensured across the covered area without weak coverage. The selection of the number of leaky coaxial cable structures, n, is based on θ1 to θ... n The tolerance depends on the choice of tolerance, tolerance |θ n -θ n-1 |≥3°.

[0029] Conventional radial leaky coaxial cables have the same radiation intensity and electromagnetic wave radiation direction at all slots on the outer conductor with the same pitch P and slot size and shape. However, the leaky coaxial cable of this invention has different pitches P along its length. Therefore, slots with different pitch intervals at different points along the leaky coaxial cable need to be designed with different sizes to ensure that the radiation electromagnetic wave intensity is basically consistent over the coverage area.

[0030] Common structures for radial leaky coaxial cables include "I"-shaped and "V"-shaped slots. The radiation from these slots is primarily related to the frequency band in use and the slot area per unit length. Generally, the slot shapes and arrangements within the same leaky coaxial cable are largely consistent; only the slot length, width, and angle are adjusted to control the radiation. The main reason is that adjusting the slot shape and arrangement (including the number and arrangement of slots within a single pitch) alters the electromagnetic wave lobe pattern radiated from the slots. This causes inconsistent electromagnetic wave lobes to form at different pitches along the leaky coaxial cable, disrupting the superposition characteristics of the periodic electromagnetic radiation structure. Specifically, the electromagnetic signal fluctuates drastically where the slot shape changes, leading to a decrease in the intensity and uniformity of the coverage field.

[0031] Because the surface current of a leaky coaxial cable is parallel to its axial direction, and the slot width W is relatively small and much smaller than the slot length L, while the slot length direction is directly opposite to the surface current direction, the slot length L of a leaky coaxial cable generally has a more significant impact on coupling loss. Based on this, the leaky coaxial cable of this invention, in order to control the electromagnetic wave radiation direction, employs periodic slots with different pitch intervals P distributed along the axial direction. The intensity of the radiation level is mainly controlled by adjusting the slot length L; that is, different pitches P and corresponding slot lengths L are set to ensure that the coupling loss along the line is comparable and the radiation direction faces the target coverage area, while the slot arrangement remains consistent.

[0032] For the coupling loss of a radial leaky coaxial cable, the approximate formula is: Where A is a fixed coefficient, λ is the electromagnetic wavelength, r is the distance from the receiving antenna to the front of the leaky coaxial cable (generally, the coupling loss value at 2 meters is taken as the standard, i.e., r = 2 meters), a r To reduce radiation attenuation in leaky coaxial cables.

[0033] The amount of radiation radiated to the target coverage area, a rn With groove length L n Number of pitches per unit length 1 / P n Radiation direction θ n The relevant formula is as follows: Formula 2; in, The leakage attenuation of the nth pitch segment of the coaxial cable is a constant; B is a fixed coefficient, also a constant; P n The nth segment pitch length between the slots of the leaky coaxial cable; θ n L is the angle between the electromagnetic radiation direction and the transmission direction of the leaky coaxial cable at the nth pitch length; n The slot length of the leaky coaxial cable is the length of the nth pitch segment.

[0034] The leaky coaxial cable of the present invention radiates to the target area through slots at various points along the axis. It should be basically consistent, that is, for the entire leaky coaxial cable, If both B and B are constants, then the parameters of a certain slot in the coaxial cable can be leaked ( It can be determined The definite value. When the electrical performance parameters of a certain slot structure at a specific wavelength band λ are obtained through testing, then for the same performance parameters... The pitch P and slot length L corresponding to the value of B can be calculated by substituting the preset θ range into Formula 1 to obtain the range of P values, and then deriving L through Formula 2.

[0035] This invention also provides a leaky coaxial cable for indoor distribution, designed using the aforementioned design method for leaky coaxial cables for indoor distribution. Specifically, the leaky coaxial cable of this invention comprises, from the inside out, an inner conductor, an insulation layer, an outer conductor, and a sheath layer. The outer conductor has periodic slots with different pitch intervals distributed along its axis. Each pitch of the leaky coaxial cable has the same coupling loss. The slot width W of the leaky coaxial cable is consistent, and the slot width is 1 / 8 to 1 / 10 of the average slot length of the multiple pitch structures. The slots are figure-eight shaped, and the slot inclination angle α varies from 15° to 30°.

[0036] Once the attenuation and coupling loss values ​​of a certain slot type are determined through testing under known parameters such as slot length L, slot width W, slot inclination angle α, and pitch P, the slot length L and pitch P values ​​corresponding to the radiation angle θ of other slots of the same series of slot types under the same attenuation, coupling, slot width W, and slot inclination angle α can be calculated using Formula 2. For a slot parameter of a certain pitch P, industry technicians can select a suitable slot for testing based on experience to determine whether the attenuation and coupling loss of the leaky coaxial cable structure with a given pitch P and slot parameters meet the usage requirements. Based on the parameters of this structure, the slot length of other leaky coaxial cables with the same attenuation and coupling loss requirements can be further calculated.

[0037] For example, Figure 8The schematic diagram of the external guide slot of the leaky coaxial cable shows that it adopts an "eight"-shaped slot arrangement. At a frequency of 2100MHz, its coupling loss is approximately 70dB, and its attenuation is approximately 5dB / 100m. The pitch is 250mm, and the slot length is approximately 20mm. The radiation direction of the leaky coaxial cable is 55°. Under the same operating frequency, wavelength, attenuation, and coupling loss performance, and with the slot width and skew angle remaining unchanged, the slot pitch for a 70° radiation angle of the leaky coaxial cable is calculated to be 180mm using Formula 1, and the slot length is calculated to be 17.8mm using Formula 2, which is comparable to the actual slot length of 18.0mm.

[0038] The present invention also provides a design system for leaky coaxial cables for indoor distribution, comprising: The electromagnetic wave radiation direction design module is configured to design different electromagnetic wave radiation direction angles along the leaky coaxial cable based on the location of the electromagnetic wave target coverage area in the target scene space. The slot pitch estimation module is configured to estimate the periodicity of the slots of the leaky coaxial cable at different electromagnetic radiation direction angles along the line designed by the electromagnetic radiation direction design module. The slot length estimation module is configured to estimate the slot length of each segment of the leaky coaxial cable based on the different electromagnetic radiation direction angles designed by the electromagnetic radiation direction design module and the periodic different pitches of the corresponding slots estimated by the slot pitch estimation module, and in combination with the requirement that the electromagnetic radiation intensity of the target coverage area is consistent.

[0039] Furthermore, the present invention also provides an electronic device comprising at least one processor and at least one memory, the memory being data-connected to the processor, wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the steps of the aforementioned design method for leaky coaxial cables for indoor distribution.

[0040] For example, the processor can be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor, etc.

[0041] Finally, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the aforementioned design method for a leaky coaxial cable for indoor distribution.

[0042] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0043] Example For a target coverage area of ​​approximately 9 meters wide and 1 meter from a window, the total length of the leaky coaxial cable for indoor distribution in this invention is 10 meters, with a structure of 5 pitches corresponding to radiation angles θ1 to θ5. The lengths of each segment are 2 meters, 2 meters, 3 meters, 2 meters, and 1 meter. Electromagnetic waves at angle θ1 cover the corner area; when θ1 is 88°, the width of the weakly covered area at the corner can be reduced to within 0.1 meters. Electromagnetic waves at angle θ5 avoid the area 1 meter from the window, with an angle of approximately 104°. Electromagnetic waves at angles θ2 to θ4 are adjusted in direction to concentrate on covering areas where people are concentrated, with their values ​​selected between 88° and 104°. Actual testing verified that for a 1-1 / 4" leaky coaxial cable with a slot length L1=17mm, a radiation angle θ1=88°, and a pitch of 132.7mm, the attenuation and coupling loss are approximately 4.9dB / 100m and 70dB respectively, and the dielectric constant is approximately 1.23. Therefore, a leaky coaxial cable with five different slot pitches was designed, with a radiation angle range of (88°, 104°) to ensure that the signal radiation is concentrated in the target coverage area. A schematic diagram of adjusting the slot radiation direction to the target area is shown below. Figure 6 As shown, the required slot pitch and slot length for other corresponding radiation angles can be calculated using Formula 1 and Formula 2. The specific electrical performance and slot parameters of the leaky coaxial cable are shown in Table 1.

[0044] Table 1. Slot electrical performance and slot parameters of the target leaky coaxial cable.

[0045] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. The present invention can also be implemented in other specific ways or forms without departing from its spirit or essential characteristics. Therefore, the described embodiments should be considered illustrative rather than limiting in any respect. The scope of the present invention should be defined by the appended claims, and any variations equivalent to the intent and scope of the claims should also be included within the scope of the present invention.

Claims

1. A design method for a leaky coaxial cable for indoor distribution, characterized in that, Includes the following steps: Step S1: Based on the location of the electromagnetic wave target coverage area in the target scene space, design different electromagnetic wave radiation direction angles along the leaky coaxial cable. Step S2: Based on the different electromagnetic wave radiation direction angles along the leaky coaxial cable designed in Step S1, calculate the periodic pitch of the slots corresponding to the different electromagnetic wave radiation direction angles of the leaky coaxial cable; wherein, the calculation formula for the pitch is as follows: Official 1; in, The equivalent dielectric constant of the insulation medium of the leaking coaxial cable; The wavelength is the frequency corresponding to the electromagnetic wave. To prevent leakage of the pitch between the coaxial cable slots; The angle between the electromagnetic radiation direction of the leaky coaxial cable and the transmission direction of the leaky coaxial cable; Step S3: Based on the different electromagnetic wave radiation direction angles designed in Step S1 and the corresponding periodic pitches of the slots calculated in Step S2, and considering the requirement that the electromagnetic wave radiation intensity of the target coverage area be consistent, calculate the slot length of each pitch segment of the leaky coaxial cable; wherein, the formula for calculating the slot length is as follows: Official 2; in, The leakage attenuation of the nth pitch segment of the coaxial cable is a constant; B is a fixed coefficient, also a constant; P n The nth segment pitch length between the slots of the leaky coaxial cable; θ n L is the angle between the electromagnetic radiation direction and the transmission direction of the leaky coaxial cable at the nth pitch length; n The slot length of the leaky coaxial cable is the length of the nth pitch segment.

2. The design method for indoor distributed leaky coaxial cable according to claim 1, characterized in that, In step S1, based on the location of the electromagnetic wave target coverage area in the target scene space, the different electromagnetic wave radiation direction angles along the leaky coaxial cable are designed, including: Based on the initial and final boundaries of the electromagnetic wave target coverage area in the target scene space, and the initial and final boundary positions of the leaky coaxial cable, the slot radiation angle boundary values ​​θ1 and θ2 at the starting and ending positions of the leaky coaxial cable are calculated. n ; The angles of the electromagnetic radiation direction in the middle section of the leaky coaxial cable are adjusted to equal intervals, i.e., from θ1 to θ... n It is an arithmetic sequence, where θ1 to θ n The number of leaky coaxial cable structures, n, is gradually increased or decreased based on θ1 to θ2. n The tolerance is determined by the choice of the arithmetic sequence |θ n -θ n-1 |≥3°.

3. A leaky coaxial cable for indoor distribution designed using the design method for leaky coaxial cables as described in any one of claims 1 or 2, characterized in that, The leaky coaxial cable comprises, from the inside out, an inner conductor, an insulation layer, an outer conductor, and a sheath layer. The outer conductor has periodic slots with different pitch intervals distributed along its axis. Each pitch of the leaky coaxial cable has the same coupling loss.

4. The leaky coaxial cable for indoor distribution according to claim 3, characterized in that, The slot width W of the leaky coaxial cable is consistent, and the slot width is 1 / 8 to 1 / 10 of the average length of the slots of the multiple pitch structures.

5. A design system for a leaky coaxial cable for indoor distribution, characterized in that, include: The electromagnetic wave radiation direction design module is configured to design different electromagnetic wave radiation direction angles along the leaky coaxial cable based on the location of the electromagnetic wave target coverage area in the target scene space. The slot pitch calculation module is configured to calculate the periodic different slot pitches of the leaky coaxial cable at different electromagnetic radiation direction angles along the cable designed by the electromagnetic radiation direction design module; wherein, the pitch calculation formula is as follows: Official 1; in, The equivalent dielectric constant of the insulation medium of the leaking coaxial cable; The wavelength is the frequency corresponding to the electromagnetic wave. To prevent leakage of the pitch between the coaxial cable slots; The angle between the electromagnetic radiation direction of the leaky coaxial cable and the transmission direction of the leaky coaxial cable; The slot length estimation module is configured to estimate the slot length of each segment of the leaky coaxial cable based on the different electromagnetic radiation direction angles designed by the electromagnetic radiation direction design module and the periodic different pitches of the corresponding slots estimated by the slot pitch estimation module, and in conjunction with the requirement that the electromagnetic radiation intensity of the target coverage area is consistent; wherein, the formula for estimating the slot length is as follows: Official 2; in, The leakage attenuation of the nth pitch segment of the coaxial cable is a constant; B is a fixed coefficient, also a constant; P n The nth segment pitch length between the slots of the leaky coaxial cable; θ n L is the angle between the electromagnetic radiation direction and the transmission direction of the leaky coaxial cable at the nth pitch length; n The slot length of the leaky coaxial cable is the length of the nth pitch segment.

6. An electronic device, characterized in that, The electronic device includes at least one processor and at least one memory, the memory being data-connected to the processor, wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the steps of the design method for an indoor distributed leaky coaxial cable as described in any one of claims 1 or 2.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, performs the steps of the design method for an indoor distributed leaky coaxial cable as described in any one of claims 1 or 2.

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