Radio frequency coaxial cable and manufacturing method thereof

Abstract

The invention provides a radio frequency coaxial cable and a manufacturing method thereof, the radio frequency coaxial cable comprises an inner conductor, the inner conductor comprises a fiber reinforced plastic matrix, the outer side of the fiber reinforced plastic matrix is concentrically coated with a first PE foaming insulation layer, and the outer side of the first PE foaming insulation layer is lapped and longitudinally coated with a copper foil layer to form the inner conductor; therefore, comprehensive performance improvement of low loss, high flexibility, light weight and long-term reliability of the cable is realized.

Description

Technical Field

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

[0002] RF coaxial cables are key components for high-frequency signal transmission in fields such as wireless communications, broadcasting, and radar systems. Their performance is directly dependent on the conductivity of the inner conductor, the dielectric loss of the insulation layer, and the mechanical properties of the overall structure. Traditional RF coaxial cables often use pure copper or copper alloys as inner conductors, produced through drawing or stranding to create solid or stranded wire structures. However, the high density of metal conductors results in excessive cable weight, making installation difficult and prone to sagging and deformation in long-distance overhead installations or mobile device applications. Furthermore, metal conductors are highly rigid, and repeated bending can easily lead to fatigue fracture, resulting in reduced signal transmission stability.

[0003] To reduce cable weight and improve flexibility, existing technologies attempt to replace pure metal conductors with lightweight composite structures. For example, existing technologies disclose a composite inner conductor with a fiber-reinforced plastic (FRP) core material and an outer copper layer, which reduces cable weight by leveraging the lightweight and high-strength properties of FRP. However, in this solution, the interfacial bonding between the copper layer and the FRP core is insufficient, and delamination and peeling easily occur under dynamic bending or temperature cycling conditions, resulting in degraded conductive performance. In addition, the thermal expansion coefficients of the FRP and copper layers differ significantly, and after long-term use, the structure is prone to cracking due to accumulated thermal stress, affecting cable reliability.

[0004] In terms of insulation layer design, traditional solutions often use solid polyethylene (PE) or physically foamed PE materials. Although solid PE insulation layers have high mechanical strength, their dielectric constant is relatively high (usually 2.3-2.4), resulting in high signal transmission loss. Conventional physically foamed PE layers reduce the dielectric constant (to below 1.5) by introducing bubbles, but the foaming uniformity is poor and the closed-cell ratio is low (usually <85%). Moisture easily penetrates the bubble gaps, causing insulation performance to deteriorate. Existing technologies propose directly coating the FRP core with a foamed PE layer to reduce losses, but this does not address the interfacial bonding problem between the foamed layer and the conductive layer (such as copper foil). Uneven bubble distribution can easily cause local electric field distortion, deteriorating the cable's return loss (RL) and voltage standing wave ratio (VSWR) indicators.

[0005] The disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the present invention. It does not necessarily belong to the prior art of this patent application, nor does it necessarily provide technical guidance. In the absence of clear evidence that the above content has been disclosed before the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of this application. Summary of the Invention

[0006] In order to solve the technical contradictions that still exist in the existing radio frequency coaxial cables in terms of lightweight, mechanical flexibility, interface bonding strength and high-frequency low-loss performance: it is difficult to achieve both lightness and flexibility by using metal conductors, and the interface reliability of composite conductors is insufficient; although the foamed insulation layer can reduce the loss, its structural stability and interface compatibility restrict the overall performance of the cable. The present invention proposes a radio frequency coaxial cable and a manufacturing method thereof to achieve comprehensive performance improvement of the cable in terms of low loss, high flexibility, lightweight and long-term reliability.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows:

[0008] On the one hand, the present invention provides a radio frequency coaxial cable, comprising: an inner conductor, the inner conductor comprising: a fiber reinforced plastic matrix, the outer side of the fiber reinforced plastic matrix is concentrically coated with a first PE foam insulation layer, and the outer side of the first PE foam insulation layer is overlapped and longitudinally coated with a copper foil layer to form an inner conductor.

[0009] The present invention provides a radio frequency coaxial cable and a manufacturing method thereof, which achieves comprehensive performance improvement of the cable in terms of low loss, high flexibility, light weight and long-term reliability.

[0010] As a preferred technical solution, the diameter of the fiber reinforced plastic matrix is 0.8-1.2 mm, the outer diameter of the first PE foam insulation layer is 4.5-5.5 mm, and the outer diameter of the copper foil layer is 0.08-0.12 mm.

[0011] As a preferred technical solution, the foaming degree of the first PE foam insulation layer is 60-78%, the first PE foam insulation layer is a full high-density first PE foam insulation layer, and the density of the full high-density first PE foam insulation layer is 0.207-0.375 g / cm 3 , closed cell rate ≥90%.

[0012] As an optimal technical solution, the copper foil is extended longitudinally along the cable and wrapped around the outside of the first PE foam insulation layer through a 6-shaped overlapping longitudinal wrapping process to form a copper foil layer. The two ends of the copper foil are overlapped at a preset angle, and the overlap rate is greater than a set threshold. The preset angle is 15°~20°, and the set threshold is 4%.

[0013] As a preferred technical solution, the first PE foam insulation layer includes: an inner skin layer, and a physical foam layer and an outer skin layer arranged in sequence from the inside to the outside of the inner skin layer. The outer skin layer is connected to the copper foil layer through the adhesive layer.

[0014] As an optimal technical solution, corrugations are formed on the surface of the inner conductor, wherein the corrugation pitch is about 1.5 to 2 times the diameter of the inner conductor, the corrugation groove width is 0.1 to 0.2 times the diameter of the inner conductor, and the corrugation depth is 0.05 to 0.1 times the diameter of the inner conductor.

[0015] As an optimal technical solution, the outer side of the inner conductor is provided with a second PE foam insulation layer, a spiral corrugated aluminum tube and a sheath from the inside to the outside. The outer diameter of the second PE foam insulation layer is 12.2 to 12.8 mm, and the wall thickness of the spiral corrugated aluminum tube is 0.25 to 0.35 mm.

[0016] The present invention provides a method for manufacturing a radio frequency coaxial cable, wherein the radio frequency coaxial cable as described above is manufactured, comprising the following steps: S1 manufacturing an inner conductor, comprising the following steps:

[0017] S101 leads the coiled fiber reinforced plastic matrix to the traction mechanism through the pay-off device;

[0018] S102 forms an inner skin layer, a physical foaming layer and an outer skin layer in sequence on the outer side of the fiber reinforced plastic matrix by a co-extrusion process to form a first PE foam insulation layer;

[0019] S103 performs cooling treatment on the first PE foam insulation layer;

[0020] S104: Adhesive is applied to the surface of the outer skin layer, and copper foil is spirally wrapped longitudinally on the outer side of the outer skin layer through a preset overlapping longitudinal wrapping mold to form a continuous overlapping copper foil layer.

[0021] As a preferred technical solution, the manufacturing of the inner conductor in step S1 further includes the following steps:

[0022] S105 performs corrugation processing on the inner conductor covered with the copper foil layer to form spiral grooves on the surface thereof;

[0023] S106 controls the outer diameter of the inner conductor to a preset size through a drawing die and a sizing die;

[0024] S107 reels the finished inner conductor through the rear traction device.

[0025] As a preferred technical solution, the following steps are included:

[0026] S2 extrude a second PE foam insulation layer around the inner conductor through a physical foaming process;

[0027] S3 uses a sizing die to draw the inner conductor covered with the second PE foam insulation layer, and adjusts the outer diameter of the inner conductor to a preset size;

[0028] S4 welds the aluminum strip into a tubular structure through argon arc welding process, and rolls the surface of the aluminum tube to form a spiral corrugated aluminum tube;

[0029] S5 is extruded outside the spiral corrugated aluminum tube to form an outer sheath, completing the overall structure of the cable.

[0030] The present invention provides a radio frequency coaxial cable and a manufacturing method thereof, which have the following beneficial effects:

[0031] 1) The present invention provides a radio frequency coaxial cable and a method for manufacturing the same, which achieves comprehensive performance improvements in terms of low cable loss, high flexibility, lightweight, and long-term reliability;

[0032] 2) The present invention provides a radio frequency coaxial cable and its manufacturing method. The first PE foam insulation layer is formed into a high closed-cell structure (≥90%) through a physical foaming process, which reduces the dielectric constant (to below 1.5), thereby reducing the dielectric loss of signal transmission. Compared with the traditional solid PE layer (dielectric constant 2.3-2.4), the attenuation index can be improved by more than 10%;

[0033] The copper foil layer longitudinally covers the foam insulation layer to form a continuous conductive shield, suppressing signal reflection and standing wave ratio (VSWR) degradation caused by electromagnetic interference (EMI);

[0034] The fiber-reinforced plastic (FRP) matrix combined with the directional arrangement of fibers provides high specific strength (tensile strength ≥ 800 MPa) and flexural modulus, preventing fatigue fracture of the metal conductor during repeated bending;

[0035] The first PE foam insulation layer has elastic deformation ability and absorbs mechanical stress through the honeycomb structure, reducing the interfacial shear stress between the copper foil layer and the FRP substrate during bending, and delaying the risk of delamination;

[0036] The fiber reinforced plastic (FRP) matrix replaces the metal core material, and the fiber reinforced plastic (FRP) matrix density (1.6 ~ 2.0g / cm 33 ) is significantly lower than copper (8.96 g / cm 33 ), combined with the low density of foamed PE (0.207~0.375g / cm 3 ), reducing the weight of the inner conductor by 40% to 50%;

[0037] Thin copper foil reduces weight, with the thickness of the copper foil layer controlled at 0.08-0.12mm, reducing metal usage while ensuring conductivity. Interface stability is enhanced, and the longitudinal overlap process of the copper foil layer is combined with an adhesive layer to enhance the interface bonding strength with the foam layer, avoiding delamination failure under temperature cycling or dynamic bending.

[0038] The full high-density first PE foam insulation layer (closed-cell rate ≥ 90%) blocks moisture penetration and prevents degradation of insulation performance, ensuring the fiber-reinforced plastic (FRP) matrix's resistance to moisture and heat aging (strength retention rate after moisture and heat aging ≥ 85%) and guaranteeing long-term structural stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic structural diagram of a radio frequency coaxial cable provided by the present invention;

[0040] Figure 2 A schematic structural diagram of an inner conductor in a radio frequency coaxial cable provided by the present invention;

[0041] Figure 3 A cross-sectional view of a radio frequency coaxial cable provided by the present invention;

[0042] Among them, 1-inner conductor; 11-fiber reinforced plastic matrix; 12-first PE foam insulation layer; 13-copper foil layer; 2-second PE foam insulation layer; 3-spiral corrugated aluminum tube; 4-sheath. DETAILED DESCRIPTION

[0043] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0044] like Figure 1-3 As shown, the present invention provides a radio frequency coaxial cable, comprising: an inner conductor 1, the inner conductor 1 comprising: a fiber reinforced plastic matrix 11, the outer side of the fiber reinforced plastic matrix 11 is concentrically coated with a first PE foam insulation layer 12, and the outer side of the first PE foam insulation layer 12 is overlapped and longitudinally coated with a copper foil layer 13 to form the inner conductor 1.

[0045] The present invention provides a radio frequency coaxial cable, the inner conductor of which is 62% to 72% lighter than a conventional copper-clad aluminum inner conductor, thereby achieving comprehensive performance improvements in terms of low cable loss, high flexibility, lightweight, and long-term reliability.

[0046] Preferably, if Figure 2As shown, the diameter of the fiber reinforced plastic matrix 11 is 0.8-1.2 mm, the outer diameter of the first PE foamed insulation layer 12 is 4.5-5.5 mm, and the outer diameter of the copper foil layer 13 is 0.08-0.12 mm; the diameter of the fiber reinforced plastic matrix 11 is preferably 0.8 mm, 1 mm and 1.2 mm. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values included in the range. The outer diameter of the first PE foamed insulation layer 12 is preferably 4.5 mm, 5 mm and 5.5 mm. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values included in the range. The outer diameter of the copper foil layer 13 is preferably 0.08 mm, 0.1 mm and 0.12 mm. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values included in the range. The reinforced plastic matrix 11 is reinforced by fiber direction, and the diameter is controlled in the range of 0.8 to 1.2 mm. It can reduce the density while ensuring tensile strength, replace the traditional metal core material, and reduce the weight of the inner conductor. The design of the first PE foam insulation layer 12 with an outer diameter of 4.5 to 5.5 mm balances the insulation performance and mechanical strength, avoiding insufficient voltage resistance due to being too thin or the introduction of extra weight due to being too thick. The copper foil layer with a thickness of 0.08 to 0.12 mm forms a continuous conductive shield through a longitudinal wrapping process, suppressing electromagnetic interference (EMI) and signal reflection, and the standing wave ratio is also reduced; the thin layer of copper foil reduces the amount of metal while meeting the conductive requirements, and combined with the fiber reinforced plastic matrix 11 to achieve the overall lightweight of the inner conductor 1; the outer diameter precision control (±0.02 mm) ensures close fit with the first PE foam insulation layer 12, avoiding electric field distortion caused by interface air gaps.

[0047] Preferably, if Figure 2 As shown, the foaming degree of the first PE foam insulation layer 12 is 60-78%, and the foaming degree of the first PE foam insulation layer 12 is preferably 60%, 69% and 78%. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values included in the range. The first PE foam insulation layer 12 is a full high-density first PE foam insulation layer, and the density of the full high-density first PE foam insulation layer is 0.207-0.375 g / cm 3 , closed cell rate ≥90%; the foaming degree of the first PE foam insulation layer 12 is controlled in the range of 60-78%, which can reduce the dielectric constant to 1.3-1.6 (compared to 2.3-2.4 of traditional solid PE), significantly reducing the dielectric loss of signal transmission; when the foaming degree of the first PE foam insulation layer 12 is lower than 80%, the honeycomb structure can still maintain uniformity, avoiding the decrease in compressive strength of the insulation layer caused by excessive pores (≥15MPa), while giving the cable better bending flexibility and deformation resistance; the first PE foam insulation layer 12 is a full high-density first PE foam insulation layer with a density lower than that of traditional solid PE (0.92-0.96g / cm3 ), combined with the foaming structure, the weight of the insulation layer can be reduced by more than 60%, which is suitable for high-altitude laying or mobile equipment scenarios; the low-density first PE foam insulation layer 12 is formed into a uniform honeycomb structure with a closed-cell rate ≥ 90% through a high-precision physical foaming process, which can not only resist external extrusion deformation, but also avoid insufficient mechanical strength due to too low density; the high closed-cell rate of the first PE foam insulation layer (closed-cell rate ≥ 90%) blocks moisture penetration (water absorption rate ≤ 0.01%), prevents insulation performance degradation in humid environments, and ensures the long-term reliability of the cable in the range of -40°C to 85°C.

[0048] Preferably, if Figure 2 As shown, the copper foil is wrapped along the longitudinal extension of the cable on the outside of the first PE foam insulation layer 12 through a 6-shaped overlapping longitudinal wrapping process to form a copper foil layer 13. The two ends of the copper foil are overlapped at a preset angle, and the overlap rate is greater than a set threshold value. The preset angle is 15° to 20°, and the set threshold value is 4%; the preset angle is preferably 15°, 18° and 20°. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values included in the range. The continuity of electromagnetic shielding is optimized: through the 6-shaped path wrapping, the copper foil layer 13 forms a continuous conductive shield, reduces electromagnetic leakage caused by axial gaps, and suppresses the skin effect and radiation interference of high-frequency signals. ; The geometric design of the overlap path is combined with the elasticity of the foamed PE insulation layer to relieve the stress concentration of the copper foil layer 13 when the cable is bent, reducing the risk of breakage; the preset overlap angle of 15°~20° makes the shear stress distribution of the copper foil layer 13 and the first PE foam insulation layer 12 more uniform, and combined with the adhesive layer, the interface bonding strength is effectively improved to prevent delamination failure; the overlap rate ≥4% forms a multi-path conductive network, even if microcracks appear in the local overlap area due to mechanical impact, it can still maintain low contact resistance and signal integrity; the high overlap rate increases the effective contact area between the copper foil layer 13 and the first PE foam insulation layer 12, disperses the bending strain energy, and delays the fatigue failure of the copper foil layer 13.

[0049] Preferably, if Figure 2 As shown, the first PE foam insulation layer 12 includes: an inner skin layer (not shown) and a physical foam layer (not shown) and an outer skin layer (not shown) arranged in sequence from the inside to the outside of the inner skin layer (not shown), and the outer skin layer (not shown) is connected to the copper foil layer 13 through the adhesive layer (not shown); the inner skin layer (not shown) isolates the fiber reinforced plastic matrix 11 and the physical foam layer (not shown) to prevent bubbles from contacting the conductor and causing local discharge; the physical foam layer (not shown) reduces the equivalent dielectric constant of signal transmission and adapts to the high-frequency transmission requirements of 5G / 6G; the outer skin layer (not shown) encapsulates the physical foam layer (not shown) to suppress impedance fluctuations caused by bubble deformation; the elastic modulus of the adhesive layer (not shown) matches the copper foil layer 13 and the outer skin layer (not shown) to disperse dynamic bending stress.

[0050] Preferably, if Figure 1 and 2 As shown, corrugations are formed on the surface of the inner conductor 1, wherein the corrugation pitch is about 1.5 to 2 times the diameter of the inner conductor 1, the corrugation groove width is 0.1 to 0.2 times the diameter of the inner conductor, and the corrugation depth is 0.05 to 0.1 times the diameter of the inner conductor; the corrugation pitch (1.5 to 2 times the diameter of the inner conductor) and the matching design of the pitch and the diameter can disperse the stress concentration when the cable is bent, reduce the risk of plastic deformation of the conductor, and improve the mechanical reliability in dynamic scenarios (bending life is increased by ≥30%); at the same time, the pitch controls the effective surface area of the conductor, Reduce the skin depth difference in high-frequency signal transmission and reduce signal attenuation; the corrugated groove width (0.1 to 0.2 times the inner conductor diameter) and the ratio of groove width to diameter are adapted to the high-frequency signal wavelength, reducing signal reflection and ensuring transmission stability. The groove width avoids excessive reduction of the conductor cross-sectional area, retains mechanical strength (tensile strength ≥ 200MPa), and prevents breakage during processing or use; the corrugated depth (0.05 to 0.1 times the inner conductor diameter) and the depth parameter regulates the electric field distribution on the conductor surface, reduces the risk of partial discharge, and improves the long-term reliability of the insulation layer.

[0051] Preferably, if Figure 1 and 3 As shown, the outer side of the inner conductor 1 is provided with a second PE foam insulation layer 2, a spiral corrugated aluminum tube 3 and a sheath 4 in sequence from the inside to the outside. The outer diameter of the second PE foam insulation layer 2 is 12.2 to 12.8 mm, and the wall thickness of the spiral corrugated aluminum tube 3 is 0.25 to 0.35 mm; the sheath 4 is a polyethylene sheath or a low-smoke flame retardant sheath, and the second PE foam insulation layer 2 (outer diameter 12.2 to 12.8 mm) is provided. The dielectric constant is reduced (1.3 to 1.6) by a physical foaming process to reduce the dielectric loss of high-frequency signal transmission; the outer diameter range of the second PE foam insulation layer 2 is adapted to the inner diameter tolerance of the spiral corrugated aluminum tube 3, and the foaming structure absorbs bending stress to avoid Rigid friction between the conductor and the aluminum tube; spiral corrugated aluminum tube 3 (wall thickness 0.25~0.35mm), the corrugated structure allows the aluminum tube to be axially compressed / tensile deformed, reducing the risk of tube wall cracking during bending, and achieving a single bending radius of 30mm and a multiple bending radius of 70mm; the spiral corrugated aluminum tube replaces the traditional copper shielding layer, reducing the weight by 30%~40%, while maintaining a shielding effectiveness of ≥60dB, adapting to high-frequency signal transmission requirements; the wall thickness range of the spiral corrugated aluminum tube 3 balances mechanical strength and molding processability; the polyethylene sheath 4 provides wear-resistant and weather-resistant protection, and its elastic modulus matches the bending stiffness of the spiral corrugated aluminum tube to avoid peeling at the interface between the polyethylene sheath and the spiral corrugated aluminum tube.

[0052] The present invention provides a method for manufacturing a radio frequency coaxial cable, wherein the radio frequency coaxial cable as described above is manufactured, comprising the following steps: S1 manufacturing an inner conductor, comprising the following steps:

[0053] S101: Lead the coiled fiber reinforced plastic matrix 11 to the traction mechanism through the pay-off device;

[0054] S102: forming an inner skin layer (not shown), a physical foaming layer (not shown), and an outer skin layer (not shown) in sequence on the outer side of the fiber reinforced plastic matrix 11 by a co-extrusion process to form a first PE foamed insulation layer 12;

[0055] S103 cools the first PE foam insulation layer 12;

[0056] S104: Adhesive is applied to the surface of the outer skin layer (not shown), and copper foil is spirally wrapped longitudinally on the outside of the outer skin layer (not shown) through a preset overlapping longitudinal wrapping mold to form a continuous overlapping copper foil layer 13.

[0057] The present invention provides a method for manufacturing a radio frequency coaxial cable. The inner conductor of the cable reduces the weight by 62% to 72% compared with a conventional copper-clad aluminum inner conductor, thereby achieving a comprehensive improvement in the cable's low loss, high flexibility, lightweight, and long-term reliability.

[0058] Preferably, the manufacturing of the inner conductor 1 in step S1 further includes the following steps:

[0059] S105: corrugating the inner conductor 1 coated with the copper foil layer 13 to form spiral grooves on its surface;

[0060] S106: The outer diameter of the inner conductor 1 is controlled to a preset size by a drawing die and a sizing die;

[0061] S107 reels the finished inner conductor 1 through the rear traction device;

[0062] The corrugation depth and drawing compression ratio are designed in a linked manner to avoid the risk of fracture caused by work hardening; the traction and winding tension is matched with the yield strength of the conductor to achieve controllable plastic deformation.

[0063] Preferably, the steps include:

[0064] S2 extrude a second PE foam insulation layer 2 around the inner conductor 1 through a physical foaming process;

[0065] S3 uses a sizing die to draw the inner conductor 1 covered with the second PE foam insulation layer 2, and adjusts the outer diameter of the inner conductor 1 to a preset size;

[0066] S4 welds the aluminum strip into a tubular structure by argon arc welding, and rolls the surface of the aluminum tube to form a spiral corrugated aluminum tube 3;

[0067] S5 extrudes the outer surface of the spiral corrugated aluminum tube 3 to form an outer sheath, completing the overall structure of the cable;

[0068] The second PE foam insulation layer 2 and the spiral corrugated aluminum tube 3 work together to reduce dielectric loss and skin effect, adapting to the high-frequency transmission requirements of 5G / 6G millimeter waves; sizing die drawing ensures the dimensional accuracy of the conductor, which not only reduces impedance fluctuations, ensures consistent impedance in subsequent cable production, and improves return loss, but also ensures the consistency and roundness of the outer diameter; the argon arc welding process is combined with the spiral corrugated aluminum tube 3 forming technology to balance lightweight and fatigue resistance.

[0069] Example 1

[0070] like Figure 1-3 As shown, the present invention provides a radio frequency coaxial cable, comprising: an inner conductor 1, the inner conductor 1 comprising: a fiber reinforced plastic matrix 11, the outer side of the fiber reinforced plastic matrix 11 is concentrically coated with a first PE foam insulation layer 12, the outer side of the first PE foam insulation layer 12 is overlapped and longitudinally coated with a copper foil layer 13 to form the inner conductor 1, the diameter of the fiber reinforced plastic matrix 11 is 1 mm, the outer diameter of the first PE foam insulation layer 12 is 5 mm, and the outer diameter of the copper foil layer 13 is 0.1 mm, wherein the outer diameter of the inner conductor 1 is 5.2 mm, the foaming degree of the first PE foam insulation layer 12 is 69%, the first PE foam insulation layer 12 is a full high-density first PE foam insulation layer, and the density of the full high-density first PE foam insulation layer 12 is 0.25 g / cm 3 , closed cell rate ≥ 90%; copper foil is wrapped along the longitudinal direction of the cable on the outside of the first PE foam insulation layer 12 by a 6-shaped overlapping longitudinal wrapping process to form a copper foil layer 13, the two ends of the copper foil are overlapped at a preset angle of 18°, and the overlap rate is greater than 4%, the first PE foam insulation layer 12 includes: an inner skin layer (not shown) and a physical foaming layer (not shown) and an outer skin layer (not shown) arranged in sequence from the inside to the outside of the inner skin layer (not shown), the outer skin layer (not shown) is connected to the copper foil layer by the adhesive layer (not shown) 13 connection; corrugations are formed on the surface of the inner conductor 1, the corrugation pitch is approximately 1.8 times the diameter of the inner conductor 1, the corrugation groove width is 0.15 times the diameter of the inner conductor 1, and the corrugation depth is 0.08 times the diameter of the inner conductor 1; a second PE foam insulation layer 2, a spiral corrugated aluminum tube 3 and a sheath 4 are provided on the outside of the inner conductor 1 from the inside to the outside; the outer diameter of the second PE foam insulation layer 2 is 12.5 mm, the wall thickness of the spiral corrugated aluminum tube 3 is 0.3 mm, and the sheath 4 is a polyethylene sheath or a low-smoke flame-retardant sheath.

[0071] Experimental methods

[0072] The experimental means for performing performance testing on the coaxial radio frequency cable of Example 1 are as follows:

[0073] Bending radius test: A bending tester is used to simulate actual bending conditions to verify whether the cable sheath cracks, shielding layer breaks, or electrical performance degrades when the bending radius reaches 30cm.

[0074] Tensile test: Use a universal material testing machine to apply an axial tensile force of up to 1000N to the cable to monitor whether the connection between the conductor and the shielding layer is broken or slipped, and record whether the deformation meets the standard.

[0075] Operating frequency response test: A vector network analyzer (VNA) is used to scan within the range of 100MHz-8GHz to analyze the insertion loss, return loss, and bandwidth characteristics of signal transmission.

[0076] Characteristic impedance test: Use a multi-point impedance meter to sample the cable in sections along its length to ensure that the impedance value is stable within the range of 50Ω±2Ω.

[0077] Attenuation constant test: At 900 MHz, the signal loss of a 100-meter cable segment was measured using a signal generator and power meter. The signal loss was compared to a standard threshold of 7.5 dB / 100 m.

[0078] Insulation resistance test: Use an insulation resistance tester to apply a 500V DC voltage to the cable, measure the insulation resistance between the conductor and the shield, and convert the unit length value to ≥10000MΩ·km.

[0079] Withstand voltage test: Apply 8000V DC voltage using a high voltage tester and maintain it for 1 minute to observe whether insulation breakdown or leakage current abnormality occurs.

[0080] Intermodulation distortion test: Use an intermodulation analyzer to input dual-frequency signals (such as 900 MHz and 910 MHz) and detect the power level of the third-order intermodulation product (such as 920 MHz) to ensure it is ≤ -155 dBc.

[0081] Weight and density comparison: A precision electronic balance was used to measure the weight of the cable per unit length (1m). Copper foil thickness measurement tools (such as a micrometer) were used to verify the lightweight design of the sheath material and conductor structure. When comparing copper-clad aluminum feeder cables, the weight difference was calculated using a density conversion formula.

[0082] The above experimental method was used to perform performance testing on the coaxial radio frequency cable of Example 1, and the results were as follows:

[0083] (1) The bending radius of the coaxial RF cable can be at least 30cm;

[0084] (2) The maximum tensile strength can reach 1000N;

[0085] (3) The operating frequency range is 100MHz to 8GHz;

[0086] (4) Characteristic impedance is 50Ω±2Ω;

[0087] (5) 900 MHz attenuation constant is not greater than 7.5 dB / 100 m;

[0088] (6) Insulation resistance greater than or equal to 10000MΩ·km;

[0089] (7) DC voltage resistance 8000V and no breakdown within one minute.

[0090] (8) Intermodulation ≤ -155dbc

[0091] (9) Low smoke flame retardant sheathed cable weight 151 ~ 156g / m (inner conductor copper foil thickness 0.06 ~ 0.10mm)

[0092] PE sheathed cable total weight 127 ~ 132g / m (inner conductor copper foil thickness 0.06 ~ 0.10mm)

[0093] The above cables are 44 to 49 g / m lighter than the copper-clad aluminum feeder of the same specification with a density of 3.1.

[0094] The above cables are 38 to 43 g / m lighter than the copper-clad aluminum feeder of the same specification with a density of 2.8.

[0095] It will be appreciated that the present invention is described through some embodiments, and it will be appreciated by those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are subject to various changes or equivalent substitutions. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope protected by the present invention.

Claims

1. A radio frequency coaxial cable, characterized in that: include: The inner conductor comprises: a fiber reinforced plastic matrix, the outer side of the fiber reinforced plastic matrix is concentrically coated with a first PE foam insulation layer, and the outer side of the first PE foam insulation layer is overlapped and longitudinally coated with a copper foil layer to form an inner conductor.

2. The radio frequency coaxial cable according to claim 1, wherein: The diameter of the fiber reinforced plastic matrix is 0.8-1.2 mm, the outer diameter of the first PE foam insulation layer is 4.5-5.5 mm, and the outer diameter of the copper foil layer is 0.08-0.12 mm.

3. The radio frequency coaxial cable according to claim 1, wherein: The foaming degree of the first PE foam insulation layer is 60-78%, the first PE foam insulation layer is a full high-density first PE foam insulation layer, and the density of the full high-density first PE foam insulation layer is 0.207-0.375 g / cm 3 , closed cell rate ≥90%.

4. The radio frequency coaxial cable according to claim 1, wherein: The copper foil is extended longitudinally along the cable and wrapped around the outside of the first PE foam insulation layer through a 6-shaped overlapping longitudinal wrapping process to form a copper foil layer. The two ends of the copper foil are overlapped at a preset angle, and the overlap rate is greater than a set threshold. The preset angle is 15° to 20°, and the set threshold is 4%.

5. The radio frequency coaxial cable according to claim 1 or 4, characterized in that: The first PE foam insulation layer includes an inner skin layer, and a physical foam layer and an outer skin layer arranged in sequence from the inside to the outside of the inner skin layer. The outer skin layer is connected to the copper foil layer through the adhesive layer.

6. The radio frequency coaxial cable according to claim 1 or 4, characterized in that: Corrugations are formed on the surface of the inner conductor, wherein the corrugation pitch is about 1.5 to 2 times the diameter of the inner conductor, the corrugation groove width is 0.1 to 0.2 times the diameter of the inner conductor, and the corrugation depth is 0.05 to 0.1 times the diameter of the inner conductor.

7. The radio frequency coaxial cable according to claim 1, characterized in that: The outer side of the inner conductor is provided with a second PE foam insulation layer, a spiral corrugated aluminum tube and a sheath in sequence from the inside to the outside. The outer diameter of the second PE foam insulation layer is 12.2-12.8 mm, and the wall thickness of the spiral corrugated aluminum tube is 0.25-0.35 mm.

8. A method for manufacturing a radio frequency coaxial cable, characterized in that: The radio frequency coaxial cable according to any one of claims 1 to 7 is manufactured, comprising the following steps: S1 manufacturing the inner conductor, comprising the following steps: S101 leads the coiled fiber reinforced plastic matrix to the traction mechanism through the pay-off device; S102 forms an inner skin layer, a physical foaming layer and an outer skin layer in sequence on the outer side of the fiber reinforced plastic matrix by a co-extrusion process to form a first PE foam insulation layer; S103 performs cooling treatment on the first PE foam insulation layer; S104: Adhesive is applied to the surface of the outer skin layer, and copper foil is spirally wrapped longitudinally on the outer side of the outer skin layer through a preset overlapping longitudinal wrapping mold to form a continuous overlapping copper foil layer.

9. The method for manufacturing a radio frequency coaxial cable according to claim 8, wherein: The manufacturing of the inner conductor in step S1 further includes the following steps: S105 performs corrugation processing on the inner conductor covered with the copper foil layer to form spiral grooves on the surface thereof; S106 controls the outer diameter of the inner conductor to a preset size through a drawing die and a sizing die; S107 reels the finished inner conductor through the rear traction device.

10. The method for manufacturing a radio frequency coaxial cable according to claim 8, wherein: The following steps are involved: S2 extrude a second PE foam insulation layer around the inner conductor through a physical foaming process; S3 uses a sizing die to draw the inner conductor covered with the second PE foam insulation layer, and adjusts the outer diameter of the inner conductor to a preset size; S4 welds the aluminum strip into a tubular structure through argon arc welding process, and rolls the surface of the aluminum tube to form a spiral corrugated aluminum tube; S5 is extruded outside the spiral corrugated aluminum tube to form an outer sheath, completing the overall structure of the cable.

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