Wide high-frequency radiation leaky coaxial cable

Abstract

The invention relates to a wide high-frequency radiation leaky coaxial cable which comprises an inner conductor, an insulating layer, an outer conductor and a sheath. And the insulating layer is arranged outside the inner conductor and is formed by blending physical foaming polyethylene and fluorinated ethylene propylene copolymer. The outer conductor is arranged outside the insulating layer. The outer conductor is provided with a plurality of large slotted hole groups which are distributed at intervals in the axial direction of the outer conductor. Each large slotted hole group comprises a fission splayed slot group, a linear slot group and a circular slotted hole. The fission splayed groove group comprises a plurality of splayed groove rows, each splayed groove row comprises at least two splayed groove holes with overlapped axes, and the axis of each splayed groove row and the axis of the outer conductor are arranged at different included angles. The linear groove set comprises at least two linear groove rows, each linear groove row comprises at least one linear long groove hole and at least one linear short groove hole, the axes of the linear long groove holes and the linear short groove holes coincide, and the arrangement sequences of the linear long groove holes and the linear short groove holes of every two adjacent linear groove rows are different. And the circular slotted hole is formed between the fission splayed slot group and the linear slot group.

Description

Technical Field

[0001] The present invention relates to the technical field of leaky cables, in particular to a wide and high frequency radiation leaky cable. Background Art

[0002] Leaky coaxial cables, which combine transmission line and antenna functions and offer excellent field coverage, have been widely used in wireless communication systems in tunnel environments, such as rail transit. With the development of 5G communication technology, the communication frequency band is expanding to higher frequencies.

[0003] However, the widely used 13 / 8" leaky coaxial cable, with a cutoff frequency generally limited to 2.8 GHz, is no longer able to meet the requirements for supporting high-frequency bands such as 3.5 GHz and 4.9 GHz. This is due to the following main problems: First, the traditional periodic slot structure limits the effective radiation of high-frequency signals, resulting in significant signal attenuation in frequency bands above 2.8 GHz. Second, this frequency limitation prevents it from directly supporting the core 3.5 GHz and 4.9 GHz bands of operators' 5G NR. Compatibility requires the deployment of additional distributed antenna systems, increasing construction costs and system complexity. Third, the single slot structure (such as the figure-eight slot) used in existing leaky cables is prone to resonance at high frequencies, resulting in an increase in the standing wave ratio (SWR), which seriously affects system transmission performance. Fourth, the periodic slot arrangement also causes distortion in the high-frequency radiation pattern, resulting in uneven wireless coverage in tunnels. Summary of the Invention

[0004] The purpose of the present invention is to provide a wide-frequency radiation leaky cable, which can improve the electromagnetic wave radiation capability and directionality control capability of the slot, significantly optimize the radiation pattern, effectively reduce the energy radiation in non-target areas, thereby improving the radiation efficiency and reducing the transmission loss, and effectively expand the frequency support range to 3.5GHz and 4.9GHz to meet the communication requirements of 5G NR.

[0005] To achieve the above object, the present invention provides a wide-high-frequency radiation leaky cable, comprising:

[0006] inner conductor;

[0007] an insulating layer, disposed outside the inner conductor, the insulating layer being formed by blending physically foamed polyethylene and fluorinated ethylene propylene copolymer;

[0008] The outer conductor is arranged outside the insulating layer, and the outer conductor is provided with a plurality of large slot groups, wherein the plurality of large slot groups are spaced apart along the axial direction of the outer conductor, and a single large slot group includes:

[0009] a fission figure-eight groove group, comprising a plurality of figure-eight groove rows spaced apart along the axis of the outer conductor, each figure-eight groove row comprising at least two figure-eight slot holes with overlapping axes, and the axis of each figure-eight groove row being arranged at a different angle to the axis of the outer conductor;

[0010] A straight slot group includes at least two straight slot rows spaced apart along the axis of the outer conductor, each straight slot row including at least one straight long slot hole and at least one straight short slot hole whose axes coincide with each other, and the arrangement order of the straight long slot holes and the straight short slot holes of two adjacent straight slot rows is different;

[0011] A circular slot hole is provided between the fission splayed slot group and the straight slot group;

[0012] The sheath is arranged outside the outer conductor.

[0013] Optionally, the outer conductor is provided with a plurality of special-shaped slots spaced apart along the axial direction of the outer conductor, and two adjacent special-shaped slots are mirror-imaged. A single special-shaped slot includes a first sub-slot and a second sub-slot that are arranged parallel to the axial direction of the outer conductor and are connected to each other. The first sub-slot and the second sub-slot are staggered in a direction perpendicular to the axial direction of the outer conductor. The edges at both ends of the special-shaped slot are correspondingly provided with chamfered corners and micro-groove arrays. The connecting corners of the first sub-slot and the second sub-slot are correspondingly provided with chamfered corners, and open annular grooves are correspondingly provided at both ends of the special-shaped slot.

[0014] Optionally, the figure-eight slot row includes two figure-eight slot holes, the angle between the axis of the figure-eight slot row and the axis of the outer conductor is ±15°-±25°, the gap between the two figure-eight slot holes in the same figure-eight slot row is 2mm-4mm, the center of the figure-eight slot row and the axis of the outer conductor are located on the same plane, the interval between the centers of two adjacent figure-eight slot rows is P / 12, the length of the figure-eight slot hole is 10mm-14mm, and the width of the figure-eight slot hole is 3mm-4mm.

[0015] Optionally, the S-shaped slot row includes one S-shaped long slot hole and one S-shaped short slot hole, the axis of the S-shaped slot row is perpendicular to the axis of the outer conductor, the gap between the S-shaped long slot hole and the S-shaped short slot hole of the same S-shaped slot row is 2mm-4mm, the center of the S-shaped slot row and the axis of the outer conductor are located on the same plane, the interval between the centers of two adjacent S-shaped slot rows is P / 10, the length of the S-shaped short slot hole is 4mm-8mm, the length of the S-shaped long slot hole is 12mm-16mm, and the widths of the S-shaped long slot hole and the S-shaped short slot hole are both 3mm-4mm.

[0016] Optionally, the center of the circular slot is located on the same plane as the axis of the outer conductor, the intervals between the circular slot and the fission figure-eight slot group and the figure-slot group are P / 8, and the diameter of the circular slot is 1.8mm-2.2mm.

[0017] Optionally, the center of the special-shaped slot and the axis of the outer conductor are located on the same plane, the interval between two adjacent special-shaped slots is P / 8, the length of the first sub-slot and the second sub-slot are both 20mm-25mm, the width of the first sub-slot and the second sub-slot are both 8mm-10mm, the radius of the chamfered corner is 0.5mm-1mm, the open annular groove is a semicircular structure and the diameter of the circle it is in is 5mm-7mm, and the length of the connecting corner of the first sub-slot and the second sub-slot is 4mm-6mm.

[0018] Optionally, the mixing ratio of physically foamed polyethylene and fluorinated ethylene propylene copolymer in the insulating layer is 70-90:10-30, and the foaming degree of the insulating layer gradually increases from the inner conductor to the outer conductor.

[0019] Optionally, a ratio of the inner diameter of the outer conductor to the outer diameter of the inner conductor is 3.08-3.12.

[0020] Optionally, the wide high frequency radiation leaky cable further includes at least one of a flame retardant layer and a wrapping layer arranged between the outer conductor and the sheath.

[0021] The beneficial effect of the present invention is that the 13 / 8" leaky cable is provided with a vertically polarized fission eight-shaped slot group, a horizontally polarized straight slot group and an omnidirectionally polarized circular slot on the outer conductor, so that the leaky cable slot type is transformed from the previous single polarization slot mode to a periodic slot structure with multiple polarization modes. This not only improves the electromagnetic wave radiation capability and directionality control capability of the slot type, but also significantly optimizes the radiation pattern, effectively reduces the energy radiation in non-target areas, thereby improving the radiation efficiency and reducing the transmission loss, and effectively expanding the frequency support range to 3.5GHz and 4.9GHz, meeting the requirements of 5G. NR communication requirements; by designing the eight-shaped slots to be arranged at irregular angles and the straight slots to be arranged asymmetrically, the slots are made to have subwavelength characteristics, thereby improving high-frequency radiation efficiency and suppressing TE mode conversion. At the same time, the overall structure of the leaky cable approaches the waveguide mode, which can utilize the TE / TM mode collaborative radiation to effectively reduce conductor loss and achieve low-loss and high-efficiency transmission in a wide band; by optimizing the insulation layer structure, using a blend of physically foamed polyethylene (FPPE) and fluorinated ethylene propylene copolymer (FEP), and setting the foaming degree to be non-uniformly distributed from the inner conductor to the outer conductor, while maintaining mechanical strength, optimizing the dielectric constant distribution, thereby suppressing high-order mode excitation in a wide frequency band, ensuring single-mode transmission, reducing transmission loss, and achieving low-loss and high-efficiency transmission in the full frequency band of 5MHz to 5GHz;

[0022] By opening special-shaped slots on the outer conductor to replace the traditional U-shaped slots, while inheriting the advantages of the U-shaped slots in multi-band compatibility, harmonic suppression capability and radiation directionality control, the radiation capability of specific high-frequency signals is enhanced, effectively suppressing the signal interference that may occur between different frequency bands, and improving the spectrum utilization efficiency of the system, thereby ensuring the stable coexistence and efficient collaborative transmission of multi-band signals in complex electromagnetic environments.

[0023] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 1 is a schematic diagram of the cross-sectional structure of a wide-high-frequency radiation leaky cable shown in one embodiment of the present invention;

[0025] Figure 2 This is a schematic structural diagram of a wide-high-frequency radiation leaky cable shown in one embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the arrangement of a large group of slots in a cycle of a wide-band high-frequency radiation leaky cable shown in one embodiment of the present invention;

[0027] Figure 4Schematic diagram of arrangement of special-shaped slots in a period of a wide-range high-frequency radiation leaky cable shown in another embodiment of the present invention;

[0028] Figure 5 Schematic diagram of attenuation simulation of a wide-high-frequency radiation leaky cable shown in one embodiment of the present invention;

[0029] Figure 6 Schematic diagram of a wide-high-frequency radiation leaky cable performing standing wave simulation according to one embodiment of the present invention;

[0030] Figure 7 Schematic diagram of attenuation simulation of a wide-high-frequency radiation leaky cable shown in another embodiment of the present invention;

[0031] Figure 8 Schematic diagram of a wide-high-frequency radiation leaky cable performing standing wave simulation according to another embodiment of the present invention;

[0032] In the figure: 1. inner conductor; 2. insulation layer; 3. outer conductor; 4. sheath; 5. large slot group; 51. fission figure-eight slot group; 511. figure-eight slot row; 512. figure-eight slot hole; 52. figure-one slot group; 521. figure-eight slot row; 522. figure-one long slot hole; 523. figure-one short slot hole; 53. circular slot hole; 6. special-shaped slot hole; 61. first sub-slot; 62. second sub-slot; 63. chamfered corner; 64. open annular groove; 7. flame retardant layer. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0036] See Figures 1 to 3 A wide-band high-frequency radiation leaky cable, as shown in a preferred embodiment of the present application, comprises an inner conductor 1, an insulating layer 2, an outer conductor 3, and a sheath 4. The insulating layer 2 is disposed outside the inner conductor 1 and is formed by a blend of physically foamed polyethylene and a fluorinated ethylene propylene copolymer. The foaming degree of the insulating layer 2 gradually increases from the inner conductor 1 to the outer conductor 3. The outer conductor 3 is disposed outside the insulating layer 2 and is provided with a plurality of large slot groups 5. The plurality of large slot groups 5 are spaced apart along the axial direction of the outer conductor 3. Each large slot group 5 includes a fission splayed slot group 51, a straight slot group 52, and a circular slot 53. The fission splayed slot group 51 includes a plurality of splayed slot rows 511 spaced apart along the axis of the outer conductor 3. Each splayed slot row 511 includes at least two splayed slots 512 whose axes coincide with each other. The axes of each splayed slot row 511 are arranged at different angles to the axis of the outer conductor 3. The slot group 52 comprises at least two slot rows 521 spaced apart along the axis of the outer conductor 3. Each slot row 521 includes at least one long slot 522 and at least one short slot 523, whose axes coincide. The order of the long slots 522 and short slots 523 in two adjacent slot rows 521 differs. A circular slot 53 is provided between the fission splayed slot group 51 and the slot group 52. The jacket 4 is disposed over the outer conductor 3.

[0037] According to the solution of the embodiment of the present invention, by combining the vertical polarization fission eight-shaped grooves, the horizontal polarization straight grooves and the omnidirectional polarization circular slots 53 on the outer conductor 3, a multi-polarization composite periodic slot structure is constructed, which significantly enhances the radiation capability and directionality control of the leaky cable, and realizes efficient radiation in high frequency bands (such as 3.5GHz and 4.9GHz), meeting the communication requirements of 5G NR. Through the design of slots with irregular angles and asymmetrical arrangements, the slot type has subwavelength characteristics, effectively improving the high-frequency radiation efficiency and suppressing TE mode conversion. At the same time, the overall structure approaches the waveguide mode, and the TE / TM mode synergistic radiation is used to reduce conductor loss. In terms of the insulating layer 2, FPPE and FEP blended materials are used and a non-uniform foaming structure is set to optimize the dielectric constant distribution. While ensuring mechanical strength, the excitation of high-order modes is suppressed, and low-loss single-mode high-efficiency transmission is achieved in the full frequency range of 5MHz to 5GHz.

[0038] See Figure 3 In one embodiment, the splayed slot row 511 includes two splayed slots 512. The included angle between the axis of the splayed slot row 511 and the axis of the outer conductor 3 is ±15°-±25°. The gap between the two splayed slots 512 in the same splayed slot row 511 is 2mm-4mm. The center of the splayed slot row 511 is coplanar with the axis of the outer conductor 3. The spacing between the centers of two adjacent splayed slot rows 511 is P / 12 (P is one period of the slot group 5). The length of the splayed slots 512 is 10mm-14mm, and the width of the splayed slots 512 is 3mm-4mm. The fission splayed slot group 51 has a dominant radiation frequency of 3.5GHz. By optimizing the slot structure to improve the uniformity of the longitudinal electric field, break the periodic resonance condition, block the conduction path of the harmonic current, meet the subwavelength radiation requirements, and thus achieve efficient and stable electromagnetic radiation performance.

[0039] See Figure 3 In one embodiment, the inline slot row 521 includes a long inline slot hole 522 and a short inline slot hole 523. The axis of the inline slot row 521 is perpendicular to the axis of the outer conductor 3. The gap between the long inline slot hole 522 and the short inline slot hole 523 of the same inline slot row 521 is 2mm-4mm. The center of the inline slot row 521 and the axis of the outer conductor 3 are located on the same plane. The interval between the centers of two adjacent inline slot rows 511 is P / 10. The length of the short inline slot hole 523 is 4mm-8mm, the length of the long inline slot hole 522 is 12mm-16mm, and the width of the long inline slot hole 522 and the short inline slot hole 523 are both 3mm-4mm. The slot group 52 enhances the radiation capability in the 4.9 GHz frequency band and destroys the current continuity in the slot structure, converting part of the energy into TM mode for effective radiation, thereby suppressing the formation of TM mode surface waves and reducing conductor losses. At the same time, the structural design effectively increases the waveguide cutoff frequency, ensuring stable single-mode transmission in the high frequency band.

[0040] See Figure 3 In one embodiment, the center of the circular slot 53 is coplanar with the axis of the outer conductor 3. The spacing between the circular slot 53 and the fission splayed slot group 51 and the splayed slot group 52 is P / 8. The diameter of the circular slot 53 is 1.8 mm to 2.2 mm. The circular slot 53 fills the zero-point region of high-frequency current, effectively enhancing current continuity and thus reducing transmission loss.

[0041] See Figure 4 In another embodiment, the outer conductor 3 is provided with a plurality of special-shaped slots 6 spaced apart along the axial direction of the outer conductor 3. By providing the special-shaped slots 6 on the outer conductor 3 instead of the traditional U-shaped slot, while inheriting the advantages of the U-shaped slot in multi-band compatibility, harmonic suppression capability, and radiation directionality control, the radiation capability of specific high-frequency signals is enhanced, the signal interference that may be generated between different frequency bands is effectively suppressed, and the spectrum utilization efficiency of the system is improved, thereby ensuring the stable coexistence and efficient collaborative transmission of multi-band signals in a complex electromagnetic environment.

[0042] Specifically, see Figure 4 The two adjacent special-shaped slots 6 are mirror-imaged. A single special-shaped slot 6 includes a first sub-slot 61 and a second sub-slot 62 that are arranged parallel to the axial direction of the outer conductor 3 and are connected to each other. The first sub-slot 61 and the second sub-slot 62 are staggered in a direction perpendicular to the axial direction of the outer conductor 3. The edges of the two ends of the special-shaped slot 6 are correspondingly provided with chamfered corners 63 and micro-groove arrays. The connecting corners of the first sub-slot 61 and the second sub-slot 62 are correspondingly provided with chamfered corners 63. Open annular grooves 64 are correspondingly opened at both ends of the special-shaped slot 6. The center of the irregular slot 6 is coplanar with the axis of the outer conductor 3. The spacing between adjacent irregular slots 6 is P / 8. The length of the first and second slots 61, 62 is 20mm-25mm, and the width of the first and second slots 61, 62 is 8mm-10mm. The radius of the chamfered corner 63 is 0.5mm-1mm. The open annular groove 64 is semicircular with a diameter of 5mm-7mm. The length of the corner connecting the first and second slots 61, 62 is 4mm-6mm. The chamfered corner 63 effectively reduces edge diffraction loss in the frequency band after the cutoff frequency, enhancing millimeter-wave compatibility. Subwavelength microgrooves are etched in the main radiating section of the irregular slot 6 to form a 3.5GHz-5GHz passband, achieving multi-band filtering. The open annular grooves 64 at each end of the irregular slot 6 suppress high-frequency clutter radiation, improving the signal's spectral purity and transmission stability.

[0043] In the above embodiment, the mixing ratio of physically foamed polyethylene and fluorinated ethylene propylene copolymer in the insulating layer 2 is 70-90:10-30. The ratio of the inner diameter of the outer conductor 3 to the outer diameter of the inner conductor 1 is 3.08-3.12. It should be noted that the insulating layer 2 of the conventional 13 / 8" leaky cable adopts physically foamed polyethylene (FPPE) material, with an equivalent dielectric constant ε of 1.248±0.015 and a foaming degree distribution of 80% uniform distribution. In one embodiment, the insulating layer 2 of the present application is made of physically foamed polyethylene (FPPE) and fluorinated ethylene propylene copolymer (FEP), and the mixing ratio is 17:3, the equivalent dielectric constant ε is 1.248±0.005, and the foaming degree distribution is a gradient distribution, which is 78%-82% from the inner conductor 1 to the outer conductor 3.

[0044] According to electromagnetic field theory, the cutoff frequency f of the leaky cable and the structural dimensions satisfy the following formula:

[0045]

[0046] Where c is the speed of light, D is the inner diameter of the outer conductor, d is the outer diameter of the inner conductor, and ε is the equivalent dielectric constant.

[0047] Conventional leaky cables are prone to severe TE / TM high-order mode interference in frequency bands above 2.8 GHz, resulting in a radiation efficiency drop of over 30%. To meet the requirements for low-loss transmission across the entire 5 MHz–5 GHz frequency band, this application, on the one hand, limits the ratio of the inner diameter D of the outer conductor 3 to the outer diameter d of the inner conductor 1. On the other hand, controlling the equivalent dielectric constant of the insulating layer 2 effectively suppresses high-order mode excitation, ensuring stable single-mode transmission within the 5 GHz frequency band, thereby achieving low-loss and high-efficiency transmission performance across the entire frequency band.

[0048] See Figure 1 and Figure 2 In the above embodiment, the wide-band high-frequency radiation leaky cable further includes a flame-retardant layer 7 and at least one of the wrapping layers disposed between the outer conductor 3 and the sheath 4 to enhance the flame retardancy or other functions of the leaky cable. In one embodiment, the flame-retardant layer 7 is disposed between the outer conductor 3 and the sheath 4 of the leaky cable.

[0049] Specifically, in the above embodiment, the thickness of the jacket 4 is 1.9±0.2mm, the thickness of the flame-retardant layer 7 / wrapping layer is 0.13±0.01mm, the thickness of the outer conductor 3 is 0.065mm-0.09mm, the thickness of the inner conductor 1 is 0.2mm-0.45mm, and the thickness of the insulation layer 2 is 12.4±0.3mm. The jacket 4 is made of materials such as halogen-free, low-smoke, flame-retardant polyolefin or low-density linear polyolefin. The flame-retardant layer 7 / wrapping layer is wrapped with mica tape, non-woven fabric, or other suitable tape. The outer conductor 3 is longitudinally wrapped with embossed copper tape. The insulation layer 2 is composed of FPPE and FEP. The inner conductor 1 is a spiral copper tube or a smooth copper tube.

[0050] In order to illustrate the various performance effects of the embodiments of the present invention, the following specific embodiments are described in detail:

[0051] Example 1:

[0052] See Figures 1 to 3 The wide-band high-frequency radiation leaky cable of this embodiment comprises an inner conductor 1, an insulating layer 2, an outer conductor 3 and a sheath 4. The insulating layer 2 is formed by blending physically foamed polyethylene and fluorinated ethylene propylene copolymer.

[0053] The outer conductor 3 is provided with a plurality of slot groups 5, which are spaced apart along the axial direction of the outer conductor 3. Each slot group 5 includes a fission splayed slot group 51, a straight slot group 52, and a circular slot 53. The fission splayed slot group 51 includes four splayed slot rows 511 spaced apart along the axis of the outer conductor 3. Each splayed slot row 511 includes two splayed slots 512 whose axes coincide. Figure 3 From left to right, the angles between the axis of each splayed slot row 511 and the axis of the outer conductor 3 are 15°, 22°, 22°, and 15°, respectively. The gap between two splayed slot holes 512 in the same splayed slot row 511 is 3 mm. The center of the splayed slot row 511 and the axis of the outer conductor 3 are coplanar. The spacing between the centers of two adjacent splayed slot rows 511 is P / 12. The length of the splayed slot hole 512 is 12 mm, and the width of the splayed slot hole 512 is 3 mm.

[0054] The slot group 52 comprises two slot rows 521 spaced apart along the axis of the outer conductor 3. Each slot row 521 includes a long slotted hole 522 and a short slotted hole 523. The long slotted holes 522 and short slotted holes 523 of the two slot rows 521 are arranged alternately. The axis of the slot rows 521 is perpendicular to the axis of the outer conductor 3. The gap between the long slotted holes 522 and the short slotted holes 523 in the same slot row 521 is 3 mm. The center of the slot row 521 is flush with the axis of the outer conductor 3. The spacing between the centers of adjacent splayed slot rows 511 is P / 10. The short slotted holes 523 are 6 mm long, the long slotted holes 522 are 14 mm long, and the width of each of the long slotted holes 522 and the short slotted holes 523 is 3 mm.

[0055] The circular slot 53 is disposed between the fission splayed groove group 51 and the straight groove group 52. The center of the circular slot 53 is coplanar with the axis of the outer conductor 3. The spacing between the circular slot 53 and the fission splayed groove group 51 and the straight groove group 52 is P / 8. The diameter of the circular slot 53 is 2 mm.

[0056] The performance of the composite slotted leaky cable of this embodiment was verified by HFSS2023R2 simulation and darkroom testing. Figure 5 As shown in Figure 2, the attenuation curve of the leaky cable is smooth overall, without obvious mutations, indicating that there is no cutoff frequency transition phenomenon; Figure 6 As shown, the standing wave ratio (VSWR) in the entire frequency band remains within 1.4, fully demonstrating the stability of single-mode transmission. In addition, the performance of the composite slot-type leaky cable of this embodiment is compared with that of the traditional single-slot-type leaky cable. It should be noted that the difference between the single-slot-type leaky cable used as a comparison and the composite slot-type leaky cable of this embodiment is only the slot type. In this embodiment, the slot type of the single-slot-type leaky cable is an eight-shaped slot. The specific comparison results are shown in Table 1 below:

[0057]

[0058] Result analysis: According to Table 1, compared with the traditional single-slot leaky cable, the radiation efficiency and field strength uniformity of the composite slot leaky cable in this embodiment are significantly improved, the transmission loss is reduced, the TE mode suppression ratio is higher, and the proportion of high-order modes is lower.

[0059] Example 2:

[0060] See Figure 4The difference between the leaky cable of this embodiment and the leaky cable of Example 1 is only the difference in the groove type on the outer conductor 3. The outer conductor 3 of the leaky cable of this embodiment is provided with four special-shaped slots 6 distributed along the axial direction of the outer conductor 3 in a period. Two adjacent special-shaped slots 6 are arranged in a mirror image. A single special-shaped slot 6 includes a first sub-slot 61 and a second sub-slot 62 arranged parallel to the axial direction of the outer conductor 3 and connected to each other. The first sub-slot 61 and the second sub-slot 62 are staggered in a direction perpendicular to the axial direction of the outer conductor 3. The edges of the special-shaped slot 6 at both ends are correspondingly provided with chamfered corners 63 and a micro-groove array. The connecting corners of the first sub-slot 61 and the second sub-slot 62 are correspondingly provided with chamfered corners 63. Open annular grooves 64 are correspondingly provided at both ends of the special-shaped slot 6. The center of the special-shaped slot 6 is located on the same plane as the axis of the outer conductor 3. The interval between two adjacent special-shaped slots 6 is P / 8. The length of the first sub-slot 61 and the second sub-slot 62 are both 22 mm. The width of the first sub-slot 61 and the second sub-slot 62 are both 8 mm. The radius of the chamfer 63 is 0.5 mm. The open annular groove 64 is a semicircular structure and the diameter of the circle in which it is located is 6 mm. The length of the connecting corner of the first sub-slot 61 and the second sub-slot 62 is 5 mm.

[0061] HFSS2023R2 was used to simulate and model the special-shaped slot 6 structure proposed in this embodiment and to conduct sample testing and verification. Figure 7 As shown in Figure 2, it can be seen that the attenuation curve of the leaky cable is generally stable, and there is no sudden change in the cutoff frequency, indicating that the transmission characteristics are continuous and stable. Figure 8 As shown, the standing wave ratio (VSWR) does not exceed 1.4 in the entire frequency band, verifying the stability of single-mode transmission. The performance indicators of the traditional U-shaped slot leaky cable and the special-shaped slot hole 6 leaky cable of this embodiment are compared. It should be noted that the difference between the U-shaped slot leaky cable used as a comparison and the special-shaped slot hole 6 leaky cable of this embodiment is only the difference in the slot shape. Specific results are shown in Table 2 below:

[0062]

[0063] Result analysis: According to Table 2, compared with the traditional U-shaped slot leaky cable, the radiation efficiency of the leaky cable with the special-shaped slot 6 in this embodiment is significantly improved, the harmonic suppression ratio and spectrum efficiency are higher, and the directivity non-circularity is lower.

[0064] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A wide-high-frequency radiation leaky cable, characterized in that: include: inner conductor; an insulating layer disposed outside the inner conductor, the insulating layer being formed by a blend of physically foamed polyethylene and fluorinated ethylene propylene copolymer, wherein the foaming degree of the insulating layer gradually increases from the inner conductor to the outer conductor; The outer conductor is arranged outside the insulating layer, and the outer conductor is provided with a plurality of large slot groups, wherein the plurality of large slot groups are spaced apart along the axial direction of the outer conductor, and a single large slot group includes: a fission figure-eight groove group, comprising a plurality of figure-eight groove rows spaced apart along the axis of the outer conductor, each figure-eight groove row comprising at least two figure-eight slot holes with overlapping axes, and the axis of each figure-eight groove row being arranged at a different angle to the axis of the outer conductor; A straight slot group includes at least two straight slot rows spaced apart along the axis of the outer conductor, each straight slot row including at least one straight long slot hole and at least one straight short slot hole whose axes coincide with each other, and the arrangement order of the straight long slot holes and the straight short slot holes of two adjacent straight slot rows is different; A circular slot hole is provided between the fission splayed slot group and the straight slot group; The sheath is arranged outside the outer conductor.

2. The wide-band high-frequency radiation leaky cable according to claim 1, characterized in that: The outer conductor is provided with a plurality of special-shaped slots spaced apart along the axial direction of the outer conductor. Two adjacent special-shaped slots are arranged in a mirror image. A single special-shaped slot includes a first sub-slot and a second sub-slot arranged parallel to the axial direction of the outer conductor and connected to each other. The first sub-slot and the second sub-slot are staggered along a direction perpendicular to the axial direction of the outer conductor. The edges at both ends of the special-shaped slot are correspondingly provided with chamfered corners and micro-groove arrays. The connecting corners of the first sub-slot and the second sub-slot are correspondingly provided with chamfered corners. Open annular grooves are correspondingly provided at both ends of the special-shaped slot.

3. The wide-band high-frequency radiation leaky cable according to claim 1, characterized in that: The figure-eight slot row includes two figure-eight slot holes, the angle between the axis of the figure-eight slot row and the axis of the outer conductor is ±15°-±25°, the gap between the two figure-eight slot holes in the same figure-eight slot row is 2mm-4mm, the center of the figure-eight slot row and the axis of the outer conductor are located on the same plane, the interval between the centers of two adjacent figure-eight slot rows is P / 12, the length of the figure-eight slot hole is 10mm-14mm, and the width of the figure-eight slot hole is 3mm-4mm.

4. The wide-band high-frequency radiation leaky cable according to claim 1, characterized in that: The inline slot row includes one inline long slot hole and one inline short slot hole, the axis of the inline slot row is perpendicular to the axis of the outer conductor, the gap between the inline long slot hole and the inline short slot hole in the same inline slot row is 2mm-4mm, the center of the inline slot row and the axis of the outer conductor are located on the same plane, the interval between the centers of two adjacent inline slot rows is P / 10, the length of the inline short slot hole is 4mm-8mm, the length of the inline long slot hole is 12mm-16mm, and the width of the inline long slot hole and the inline short slot hole are both 3mm-4mm.

5. The wide-band high-frequency radiation leaky cable according to claim 1, characterized in that: The center of the circular slot is located on the same plane as the axis of the outer conductor. The intervals between the circular slot and the fission figure-eight slot group and the figure-slot group are both P / 8. The diameter of the circular slot is 1.8mm-2.2mm.

6. The wide-band high-frequency radiation leaky cable according to claim 2, characterized in that: The center of the special-shaped slot is located on the same plane as the axis of the outer conductor. The interval between two adjacent special-shaped slots is P / 8. The lengths of the first sub-slot and the second sub-slot are both 20mm-25mm. The widths of the first sub-slot and the second sub-slot are both 8mm-10mm. The radius of the chamfered corner is 0.5mm-1mm. The open annular groove is a semicircular structure and the diameter of the circle in which it is located is 5mm-7mm. The length of the connecting corner of the first sub-slot and the second sub-slot is 4mm-6mm.

7. The wide-band high-frequency radiation leaky cable according to claim 1, characterized in that: The mixing ratio of the physically foamed polyethylene to the fluorinated ethylene propylene copolymer in the insulating layer is 70-90:10-30.

8. The wide-band high-frequency radiation leaky cable according to claim 1, characterized in that: The ratio of the inner diameter of the outer conductor to the outer diameter of the inner conductor is 3.08-3.

12.

9. The wide-band high-frequency radiation leaky cable according to claim 1, characterized in that: The invention also includes at least one of a flame retardant layer and a wrapping layer disposed between the outer conductor and the jacket.

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