A design method for a low-loss cable connector without resonance point

Abstract

The invention belongs to the technical field of connectors and discloses a design method for a low-loss cable connector without resonance points, comprising: designing a spiral gradient groove structure on the surface of an inner conductor based on the impedance continuity principle, establishing a composite gradient impedance theoretical model of the connector, constructing a dielectric constant gradient distribution model of a double insulating layer, and setting a transition function between an inner layer and an outer layer; solving the S parameters and electric field distribution of the connector through electromagnetic-thermal coupling finite element simulation, optimizing the spiral angle θ and the gradient index n, establishing a quantitative model of the surface roughness of the conductor and high-frequency loss, and determining a threshold range of the surface roughness through calculation of the quantitative model; performing global optimization of structural parameters based on a multi-objective genetic algorithm, outputting a theoretical design parameter set and a report collection of performance verification, eliminating the resonance point problem of traditional connectors, and providing excellent low-loss performance in the full frequency band, which is particularly suitable for high-frequency and high-power transmission environments.

Description

Technical Field

[0001] The invention relates to the technical field of cables, and in particular to a design method for a low-loss cable connector without a resonance point. Background Art

[0002] From home appliances to smartphones, computers, network equipment, etc., cable connectors play a vital role as important components for connecting and transmitting signals. Especially in applications such as high-definition video transmission, high-definition audio equipment, and computer network connections in home and office environments, the performance requirements for cable connectors are getting higher and higher. In order to ensure signal integrity and reduce signal interference and loss, the market demand for low-loss, resonance-free cable connectors is increasing. The quality of cable connectors directly affects the performance stability of the equipment, especially in the transmission of high-frequency signals. High-quality cable connectors can greatly improve the efficiency and stability of signal transmission between devices.

[0003] Most existing cable connectors use traditional impedance matching technology, which is usually based on a fixed impedance design and can meet the needs of ordinary low-frequency signal transmission. However, as the signal frequency increases, especially in high-frequency scenarios such as high-definition video and high-speed data transmission, the impedance matching of traditional connectors often leads to signal reflection and loss problems, which manifests as higher insertion loss and return loss. In addition, due to the simple structure of traditional connectors, they cannot effectively avoid the resonance phenomenon of high-frequency signals, resulting in resonance points in the frequency response, which not only affects the stability of the signal, but also increases the overall power consumption of the device.

[0004] In view of this, it is necessary to improve the design and development of the cable connector in the prior art to solve the technical problems of signal reflection and resonance caused by impedance mutation. Summary of the invention

[0005] The purpose of the present invention is to provide a design method for a low-loss cable connector without a resonance point, so as to solve the above technical problems.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A design method for a low-loss cable connector without a resonance point, comprising:

[0008] S1, based on the impedance continuity principle, the spiral gradient groove structure on the surface of the inner conductor is designed, the composite gradient impedance theoretical model of the connector is established, and the mapping relationship between the geometric parameters of the spiral gradient groove of the inner conductor and the equivalent impedance Z (x) is defined; the geometric parameters include the groove depth h, the spiral angle θ and the spiral period Λ;

[0009] S2, constructing a dielectric constant gradient distribution model of the double insulating layer and setting the transition function between the inner layer and the outer layer; wherein the inner layer radius is R1 and the outer layer radius is R2;

[0010] S3, through electromagnetic-thermal coupling finite element simulation, solve the S parameters and electric field distribution of the connector, optimize the spiral angle θ and the gradient index n, so that the voltage standing wave ratio VSWR is lower than the first preset value and the insertion loss IL does not exceed the second preset value;

[0011] S4, establishing a quantitative model of conductor surface roughness and high-frequency loss, and determining a threshold range of surface roughness through calculation of the quantitative model;

[0012] S5, structural parameters based on multi-objective genetic algorithm Perform global optimization, the objective function is , weight coefficients w1=0.5, w2=0.3, w3=0.2;

[0013] S6, outputting a set of theoretical design parameter sets and a report collection of performance verification, wherein the report collection includes an impedance distribution curve, an electric field uniformity analysis result, and a full-band scattering parameter matrix.

[0014] Optionally, the inner layer is made of foamed polytetrafluoroethylene with a low dielectric constant. =1.8; the outer layer is a high dielectric constant boron nitride nanotube composite medium filled with a dielectric constant of =3.2.

[0015] Optionally, the S1 specifically includes:

[0016] S11, construct a segmented spiral gradient groove on the axial surface of the inner conductor of the connector, wherein the spiral gradient groove is composed of alternating deep groove segments and shallow groove segments, and the depth of the deep groove segment is =0.3mm, shallow groove depth =0.1mm, the helix angle θ changes linearly from 30° to 60°, and adjacent groove segments are connected by a smooth transition zone;

[0017] S12, define the equivalent impedance distribution function Z (x) of the spiral gradient groove, and establish the mapping relationship between the groove depth h, the spiral angle θ and the equivalent impedance through the mathematical method of exponential decay superposition sine modulation, where the groove depth h (x) changes with the axial position x according to Regular attenuation, the helix angle θ(x) and the axial projection length satisfy the linear constraint of tanθ(x)=k·x+b;

[0018] S13, the spiral period Λ and the attenuation coefficient α are optimized by parametric scanning, and the impedance continuity is verified by finite element simulation, so that the impedance fluctuation ΔsZ between adjacent slot segments is ≤1Ω, and the full axial impedance deviation |Z(x)-50Ω| is ≤2Ω.

[0019] Optionally, after S13, the step further includes:

[0020] S14, a chamfer structure is set at the bottom of the deep groove section, and the field-circuit collaborative simulation is used to calculate the smoothing effect of the chamfer on the electric field distribution, reducing the maximum field strength from 350V / m to below 220V / m;

[0021] S15, based on parameter sensitivity analysis, determine the allowable range of key geometric parameters: helix angle θ∈[30°, 60°], helix period Λ∈[2mm, 5mm], attenuation coefficient α∈[0.1, 0.3]. If the allowable range is exceeded, an impedance mutation alarm is triggered;

[0022] S16, generating a three-dimensional parameterized model and an impedance distribution curve of the spiral gradient groove, and outputting a design specification file.

[0023] Optionally, the S2 specifically includes:

[0024] S21, determine the material composite system of the double insulation layer, the inner layer is a mixed material of foamed polytetrafluoroethylene and hollow glass microspheres, and the outer layer is a boron nitride nanotube / liquid silicone composite material. The nonlinear relationship between the dielectric constant and the component changes is determined through a material compounding experiment, thereby obtaining a material ratio table;

[0025] S22, define the transition function of the dielectric constant gradient and establish the dielectric constant distribution equation with radial position r as the variable:

[0026] ,

[0027] Where n is the gradient index;

[0028] S23, develop parametric modeling tools to import the dielectric constant distribution equation into 3D electromagnetic simulation software, generate solid models of insulating layers with non-uniform material properties, and verify the design goal of the peak electric field strength not exceeding 150 V / mm.

[0029] Optionally, after S23, the step further includes:

[0030] S24, setting a periodic microstructure in the transition zone, wherein the periodic microstructure is specifically a honeycomb through-hole array with a pore diameter of 50 μm and a spacing of 100 μm, optimizing the microstructure morphology through finite element simulation, and obtaining a microstructure processing tolerance;

[0031] S25, determining the polarization characteristics of the material composite system based on a dielectrophoresis experiment, modifying the dielectric constant theoretical model, and establishing a three-dimensional relationship map of component-dielectric constant-temperature to optimize the material ratio table;

[0032] S26, output the design specification file of the double insulation layer, including the material ratio table, the allowable range of gradient index and the microstructure processing tolerance.

[0033] Optionally, the S3 specifically includes:

[0034] S31, establish the coupling simulation model of the connector, and transform the geometric parameters (h, θ, Λ) of the spiral gradient groove and the gradient distribution parameters of the double insulation layer Import electromagnetic-thermal joint solver;

[0035] S32, divide the adaptive grid in the target frequency band, use local encrypted grid for the spiral groove area, and set the boundary condition as radiation absorption boundary;

[0036] S33, perform full-wave electromagnetic simulation to extract the S parameter matrix, calculate the voltage standing wave ratio VSWR and the insertion loss IL, and calculate the conductor loss power density distribution through the Joule heat model.

[0037] Optionally, after S33, the step further includes:

[0038] S34, based on parameter sensitivity analysis, determine the influence weights of the helix angle θ and the gradient index n on VSWR and IL, and establish the parameter adjustment priority: , by iteratively optimizing the spiral angle θ and the gradient index n, where the step size of the optimization iteration is set to θ±1° and n±0.2;

[0039] S35, setting dynamic convergence criteria, when VSWR changes <0.01 for three consecutive iterations and IL changes <0.005dB / m, it is determined to be converged, the voltage standing wave ratio VSWR after convergence is lower than the first preset value, and the insertion loss IL does not exceed the second preset value.

[0040] Optionally, the S4 specifically includes:

[0041] S41, using a three-dimensional surface profiler to measure the surface morphology of the conductor, extract the roughness amplitude Δs, the average spacing RSm and the fractal dimension D, and construct a non-Gaussian random surface model, where the fractal dimension D∈[2.3, 2.6];

[0042] S42, based on the modified skin effect theory, establish a rough surface AC resistance frequency-dependent model, define the functional relationship between high-frequency loss and roughness parameters (Δs, RSm, D), and calibrate the model coefficients by measuring the target frequency band 10-40GHz loss data with a vector network analyzer, and calibrate the rough surface AC resistance frequency-dependent model;

[0043] S43, generating a plurality of groups of random rough surface samples based on Monte Carlo simulation, inputting the calibrated rough surface AC resistance frequency-dependent model to calculate the loss distribution at each frequency point, and determining the critical roughness threshold ΔS.

[0044] Optionally, the S5 specifically includes:

[0045] S51, construct a multidimensional parameter space and define the optimization variable set: spiral groove depth h∈[0.1mm, 0.3mm], spiral angle θ∈[30°, 60°], spiral period Λ∈[2mm, 5mm], gradient index n∈[2.0, 3.0], inner radius =2.5mm±0.1mm, outer radius =4.0mm±0.2mm;

[0046] S52, initializing the multi-objective genetic algorithm population, setting the population size, the crossover probability 0, the mutation probability, and loading the simulation database as the initial training set;

[0047] S53, define the fitness function:

[0048] ,

[0049] Set up constraints:

[0050] ;

[0051] S54, performs adaptive optimization iterations, screens non-inferior solution sets in each generation, and dynamically adjusts crossover / mutation probabilities;

[0052] S55, evaluate the quality of structural parameters by Monte Carlo method, perform process tolerance analysis on the optimal solution set, and eliminate solutions with sensitivity > 0.5dB / m / μm;

[0053] S56, output the Pareto optimal solution set and three-dimensional performance cloud diagram, generate a parameter combination priority ranking table, and mark the manufacturability level.

[0054] Compared with the prior art, the present invention has the following beneficial effects: firstly, a mapping model of the geometric parameters of the spiral gradient groove of the inner conductor and the equivalent impedance is established based on the impedance continuity principle, and the interface electric field distortion is eliminated by the double insulating layer dielectric gradient distribution model; then, the key parameters are optimized by electromagnetic-thermal coupling simulation, and the quantitative relationship between surface roughness and high-frequency loss is established; finally, the structural parameters are globally optimized by a multi-objective genetic algorithm, and a theoretical design specification and a verification report are output; the method solves the resonance problem caused by impedance mutation in the prior art through the spiral gradient groove structure and the double insulating layer gradient design, avoids high-frequency signal reflection and insertion loss, and at the same time, by optimizing the surface roughness of the conductor, reduces the high-frequency loss caused by the skin effect, thereby effectively improving the stability and efficiency of signal transmission; this design not only eliminates the resonance point problem of the traditional connector, but also provides excellent low-loss performance in the full frequency band, and is particularly suitable for high-frequency and high-power transmission environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0056] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical contents disclosed by the present invention.

[0057] Figure 1 This is one of the flow charts of the design method of the low-loss cable connector without resonance point according to the first embodiment of the present invention;

[0058] Figure 2 This is a second flow chart of the design method of the low-loss cable connector without resonance point according to the first embodiment of the present invention;

[0059] Figure 3 It is a simplified cross-sectional schematic diagram of a low-loss cable connector without resonance points according to the second embodiment of the present invention. DETAILED DESCRIPTION

[0060] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] In the description of the present invention, it should be understood that the terms "upper", "lower", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. It should be noted that when a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally arranged component at the same time.

[0062] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0063] Embodiment 1:

[0064] Combination Figures 1 to 3 As shown, an embodiment of the present invention provides a design method for a low-loss cable connector without a resonance point, comprising:

[0065] S1, based on the impedance continuity principle, the spiral gradient groove structure on the surface of the inner conductor is designed, the composite gradient impedance theoretical model of the connector is established, and the mapping relationship between the geometric parameters of the spiral gradient groove of the inner conductor and the equivalent impedance Z (x) is defined; the geometric parameters include the groove depth h, the spiral angle θ and the spiral period Λ;

[0066] By adjusting the groove depth and spiral angle, a smooth transition of equivalent impedance from the center to the edge is achieved, avoiding signal reflection caused by step-like mutations.

[0067] S2, constructing a dielectric constant gradient distribution model of the double insulating layer and setting the transition function between the inner layer and the outer layer; wherein the inner layer radius is R1 and the outer layer radius is R2;

[0068] By setting the transition function between the inner layer and the outer layer, the continuous gradual change of the dielectric constant between the two layers is controlled to eliminate the electric field distortion at the interface.

[0069] S3, through electromagnetic-thermal coupling finite element simulation, solve the S parameters and electric field distribution of the connector, optimize the spiral angle θ and the gradient index n, so that the voltage standing wave ratio VSWR is lower than the first preset value and the insertion loss IL does not exceed the second preset value;

[0070] The electromagnetic field and thermal field coupling simulation technology is used to optimize the spiral groove geometric parameters and the gradient distribution of the insulation layer to ensure that the voltage standing wave ratio of the connector is lower than 1.1 within the target frequency band and the insertion loss does not exceed 0.15dB / m.

[0071] S4, establishing a quantitative model of conductor surface roughness and high-frequency loss, and determining a threshold range of surface roughness through calculation of the quantitative model;

[0072] A correlation model between conductor surface roughness and high-frequency loss is established, and the threshold range of surface roughness is determined through theoretical calculation to guide the plating process design to suppress the skin effect.

[0073] S5, structural parameters based on multi-objective genetic algorithm Perform global optimization, the objective function is , weight coefficients w1=0.5, w2=0.3, w3=0.2;

[0074] A multi-objective optimization algorithm is used to balance impedance matching, loss suppression and structural manufacturability to generate the optimal parameter combination that meets the requirements of no resonance point and low loss.

[0075] S6, outputs a report collection of theoretical design parameter sets and performance verification, which includes impedance distribution curves, electric field uniformity analysis results and full-band scattering parameter matrix.

[0076] It should be noted that the main part of the cable connector in this solution does not include the connection terminal part, but the part for connecting the cable connector to the cable, which is also the key position to ensure low-loss performance without resonance point.

[0077] The working principle of the present invention is as follows: first, a mapping model of the geometric parameters of the spiral gradient groove of the inner conductor and the equivalent impedance is established based on the impedance continuity principle, and the interface electric field distortion is eliminated through the double insulation layer dielectric gradient distribution model; then, the key parameters are optimized by electromagnetic-thermal coupling simulation, and the quantitative relationship between the surface roughness and the high-frequency loss is established; finally, the structural parameters are globally optimized by a multi-objective genetic algorithm, and the theoretical design specification and verification report are output; the method solves the resonance problem caused by impedance mutation in the prior art through the spiral gradient groove structure and the double insulation layer gradient design, avoids high-frequency signal reflection and insertion loss, and at the same time, by optimizing the surface roughness of the conductor, reduces the high-frequency loss caused by the skin effect, thereby effectively improving the stability and efficiency of signal transmission; this design not only eliminates the resonance point problem of the traditional connector, but also provides excellent low-loss performance in the full frequency band, and is particularly suitable for high-frequency and high-power transmission environments.

[0078] In this embodiment, it is specifically described that the inner layer is made of foamed polytetrafluoroethylene with a low dielectric constant. =1.8; the outer layer is filled with high dielectric constant boron nitride nanotube composite medium, its dielectric constant =3.2.

[0079] In this embodiment, it is specifically described that S1 specifically includes:

[0080] S11, a segmented spiral gradient groove is constructed on the axial surface of the inner conductor of the connector. The spiral gradient groove consists of alternating deep groove segments and shallow groove segments. The depth of the deep groove segment is =0.3mm, shallow groove depth =0.1mm, the helix angle θ changes linearly from 30° to 60°, and adjacent groove segments are connected by a smooth transition zone; the transition length accounts for 15%-20% of the helix period Λ;

[0081] The step-by-step impedance change is achieved by alternating deep and shallow grooves, avoiding the local impedance mismatch of the traditional single groove depth; the linear change of the spiral angle compensates for the impedance drop caused by the high-frequency skin effect. The segmented design breaks the periodic structure and suppresses the generation of resonance points (traditional continuous spiral grooves are prone to forming standing waves at specific frequencies).

[0082] S12, define the equivalent impedance distribution function Z (x) of the spiral gradient groove, and establish the mapping relationship between the groove depth h, the spiral angle θ and the equivalent impedance through the mathematical method of exponential decay superposition sine modulation, where the groove depth h (x) changes with the axial position x according to Regular attenuation, the helix angle θ(x) and the axial projection length satisfy the linear constraint of tanθ(x)=k·x+b;

[0083] The physical structural parameters (h, θ) are converted into quantifiable impedance distribution Z(x), providing a theoretical basis for simulation optimization. Exponential decay dominates the impedance gradient trend, and the sinusoidal term (implicit in the groove depth fluctuation) suppresses the periodic impedance fluctuation (amplitude ±0.05mm).

[0084] S13, the spiral period Λ and the attenuation coefficient α are optimized by parametric scanning, and the impedance continuity is verified by finite element simulation, so that the impedance fluctuation ΔsZ between adjacent slot segments is ≤1Ω, and the full axial impedance deviation |Z(x)-50Ω| is ≤2Ω.

[0085] Screen the combination of Λ and α that meets impedance continuity to ensure broadband matching performance. Parameter scanning combined with electromagnetic simulation replaces the traditional trial and error method, improving efficiency by 80%. Generate simulation input based on the mathematical model of S12, and the optimization results are used to modify the structural parameters of S11 (for example, impedance continuity is optimal when Λ=3.2mm).

[0086] S14, a chamfer structure is set at the bottom of the deep groove section, and the field-circuit collaborative simulation is used to calculate the smoothing effect of the chamfer on the electric field distribution, reducing the maximum field strength from 350V / m to below 220V / m;

[0087] Eliminate the electric field concentration caused by the sharp corners at the bottom of the slot and improve the withstand voltage level (from 300V RMS to 500V RMS). The chamfer design improves the uniformity of the electric field distribution by 40% and avoids the risk of local breakdown. The optimized Λ and α determine the slot geometry, and the chamfer parameters need to be consistent with the slot depth. Compatible (Chamfer radius ).

[0088] S15, based on parameter sensitivity analysis, determine the allowable range of key geometric parameters: helix angle θ∈[30°, 60°], helix period Λ∈[2mm, 5mm], attenuation coefficient α∈[0.1, 0.3]. If the allowable range is exceeded, an impedance mutation alarm is triggered;

[0089] Quantify the impact of manufacturing tolerances on performance and define acceptable parameter fluctuation ranges. Parameter sensitivity thresholds (e.g., Δθ = ±1° leads to ΔZ = ±0.5Ω) are directly related to process control criteria. Determine parameter boundaries based on S13 simulation data and S14 electric field optimization results.

[0090] S16, generates a three-dimensional parametric model and impedance distribution curve of the spiral gradient groove, and outputs a design specification file, including the groove geometry tolerance (±0.02mm), axial position coding rules and impedance tolerance threshold.

[0091] In this embodiment, it is specifically described that S2 specifically includes:

[0092] S21, determine the material composite system of the double insulation layer, the inner layer is a mixed material of foamed polytetrafluoroethylene and hollow glass microspheres, and the outer layer is a boron nitride nanotube / liquid silicone composite material. The nonlinear relationship between the dielectric constant and the component changes is determined through a material compounding experiment, thereby obtaining a material ratio table;

[0093] Choose low dielectric constant inner layers ( =1.8) to reduce signal loss, high dielectric constant outer layer ( =3.2) Enhance mechanical strength and quantify component-property relationships through experimental data.

[0094] Hollow glass microspheres (30μm in diameter) make the inner layer porosity reach 40%, and the dielectric constant is 15% lower than that of pure PTFE; boron nitride nanotubes (aspect ratio > 200) are arranged in a directional manner to form a thermal conductive network.

[0095] The material ratio table is used as the core input of the S22 gradient function to ensure that the deviation between the theoretical value of the dielectric constant and the measured value is less than 2%.

[0096] S22, defines the transition function of the dielectric constant gradient, based on the inner radius =2.5mm, outer radius =4.0mm, the dielectric constant distribution equation with radial position r as variable is established:

[0097] ,

[0098] Where n is the gradient index;

[0099] The change law of the dielectric constant of the double insulating layer is mathematically calculated to avoid the electric field distortion caused by step mutation. The power function model (n=2.5) makes the dielectric constant change smoothly in the transition zone, and the fluctuation of the gradient change rate is compressed to ±5% (the fluctuation of the traditional linear model is >±15%).

[0100] S21 material ratio table ( =1.8, =3.2) is directly substituted into the equation to provide a theoretical basis for the parametric modeling of S23.

[0101] S23, develop parametric modeling tools to import the dielectric constant distribution equation into 3D electromagnetic simulation software, generate solid models of insulating layers with non-uniform material properties, and verify the design goal of the peak electric field strength not exceeding 150 V / mm.

[0102] The theoretical model was converted into a simulable 3D entity to verify the uniformity of the electric field distribution. The model was generated based on the gradient equation, and the simulation results (the peak field strength dropped from 280V / m to 150V / m) were fed back to the microstructure optimization of S24.

[0103] S24, a periodic microstructure is set in the transition zone. The periodic microstructure is specifically a honeycomb through-hole array with a pore size of 50μm and a spacing of 100μm. The microstructure morphology is optimized by finite element simulation to obtain the microstructure processing tolerance; the fluctuation range of the dielectric constant gradient change rate is controlled within ±5%.

[0104] S25, based on the dielectrophoresis experiment, the polarization characteristics of the composite material system are determined, the dielectric constant theoretical model is modified, and a three-dimensional relationship map of component-dielectric constant-temperature is established to optimize the material ratio table; (temperature range -55℃ to 125℃);

[0105] Quantify the effect of temperature on dielectric properties (e.g. The dielectric anisotropy of the nanotubes was Δε=±0.05, which was 3.25 at -55°C and 3.15 at 125°C, supporting the wide temperature range design. The dielectrophoresis experiment revealed the influence of nanotube orientation on dielectric anisotropy (Δε=±0.05), correcting the deviation of the theoretical model.

[0106] A material ratio table adjusted based on experimental data feedback (e.g. the upper limit of the volume fraction of outer layer boron nitride is tightened from 25% to 23%), and temperature compensation rules are added to the specification document.

[0107] S26, output the design specification file of the double insulation layer, including the material ratio table, the allowable range of gradient index and the microstructure processing tolerance.

[0108] Allowable range of gradient index: S22 (gradient transition function): The gradient index n=2.5 is initially set, but its allowable range needs to be verified through subsequent steps.

[0109] S24 (microstructure optimization): Simulation found that when n < 2.0, the dielectric constant gradient change rate fluctuates by more than ±10%, resulting in electric field distortion; when n > 3.0, the proportion of outer layer material is too high, and the mechanical strength decreases. Therefore, n∈[2.0, 3.0].

[0110] S25 (Temperature Effect): When the temperature changes, the value of n needs to compensate for the difference in the thermal expansion coefficient of the material, further constraining the allowable range of n.

[0111] In this embodiment, it is specifically described that S3 specifically includes:

[0112] S31, establish the coupling simulation model of the connector, and transform the geometric parameters (h, θ, Λ) of the spiral gradient groove and the gradient distribution parameters of the double insulation layer Import the electromagnetic-thermal joint solver; integrate structural parameters and material properties to achieve collaborative simulation of electromagnetic loss (S parameters) and temperature rise (Joule heat).

[0113] S32, divide the adaptive grid in the target frequency band, use local refined grid for the spiral groove area (minimum grid size λ / 50, λ is the wavelength corresponding to the highest frequency), and set the boundary condition as radiation absorption boundary (PML layer number = 8);

[0114] An adaptive grid is divided within the target frequency band (DC-40GHz), a local encrypted grid is used for the spiral groove area (minimum size λ / 50, λ=40GHz corresponds to a wavelength of 7.5mm), and 8 perfectly matched layers (PMLs) are set as radiation absorption boundaries.

[0115] Improve the simulation accuracy of high-frequency field distribution (λ / 50 grid can resolve 0.15mm details), suppress boundary reflection errors (PML attenuates reflection to below -60dB). Dynamic mesh encryption technology allows computing resources to be concentrated in key areas (spiral grooves), and the geometric parameters of S31 (such as Λ=3.2mm) determine the mesh division density to ensure accurate capture of the field distribution at the groove edge.

[0116] S33, performing full-wave electromagnetic simulation to extract the S parameter matrix, calculating the voltage standing wave ratio VSWR and the insertion loss IL, and calculating the conductor loss power density distribution through the Joule heat model;

[0117] Verify impedance matching (VSWR) and signal integrity (IL), and evaluate thermal reliability (temperature rise <15°C). The joint solver realizes real-time interaction between electromagnetic and thermal fields, for example, the power loss at 40GHz frequency is directly mapped to heat source input.

[0118] S34, based on parameter sensitivity analysis, determine the influence weights of the helix angle θ and the gradient index n on VSWR and IL, and establish the parameter adjustment priority: , by iteratively optimizing the spiral angle θ and the gradient index n, where the step size of the optimization iteration is set to θ±1° and n±0.2.

[0119] S36, set dynamic convergence criteria, and determine convergence when VSWR changes less than 0.01 and IL changes less than 0.005dB / m for three consecutive iterations. The voltage standing wave ratio VSWR after convergence is lower than the first preset value, and the insertion loss IL does not exceed the second preset value.

[0120] Set dynamic convergence conditions: Convergence is determined when VSWR changes less than 0.01 for three consecutive iterations and IL changes less than 0.005 dB / m, ultimately ensuring VSWR ≤ 1.1 and IL (f = 20 GHz) ≤ 0.15 dB / m.

[0121] In this embodiment, it is specifically described that S4 specifically includes:

[0122] S41, a three-dimensional surface profiler is used to measure the surface morphology of the conductor, extract the roughness amplitude Δs, average spacing RSm and fractal dimension D, and construct a non-Gaussian random surface model, where the fractal dimension D∈[2.3, 2.6]; the measurement data is directly used to construct the rough surface AC resistance model, and the fractal dimension D is used as the key input parameter.

[0123] S42, based on the modified skin effect theory, establishes a frequency-dependent model of AC resistance of rough surface, defines the functional relationship between high-frequency loss and roughness parameters (Δs, RSm, D), and calibrates the model coefficients by measuring the loss data of the target frequency band 10-40GHz with a vector network analyzer. The frequency-dependent model of AC resistance of rough surface is calibrated; the roughness parameters are converted into quantifiable high-frequency loss indicators to support the determination of critical thresholds.

[0124] S43, based on Monte Carlo simulation, several groups of random rough surface samples are generated, and the calibrated rough surface AC resistance frequency-dependent model is input to calculate the loss distribution of each frequency point, and the critical roughness threshold ΔS is determined. The output threshold ΔSmax is used for process tolerance analysis in S5.

[0125] The critical roughness threshold ΔSmax=0.05 μm is actually determined, and when ΔS>0.05 μm, the 40 GHz loss increases sharply by>0.02 dB / m.

[0126] In this embodiment, it is specifically described that S5 specifically includes:

[0127] S51, construct a multidimensional parameter space and define the optimization variable set: spiral groove depth h∈[0.1mm, 0.3mm], spiral angle θ∈[30°, 60°], spiral period Λ∈[2mm, 5mm], gradient index n∈[2.0, 3.0], inner radius =2.5mm±0.1mm, outer radius =4.0mm±0.2mm;

[0128] The parameter range is based on the simulation and experimental data of S1-S4, and the roughness threshold ΔSmax is used as one of the constraints to limit the optimization range of h and θ.

[0129] S52, initialize the multi-objective genetic algorithm population, set the population size, crossover probability 0, mutation probability, and load the simulation database as the initial training set.

[0130] S53, define the fitness function:

[0131] ,

[0132] Set up constraints:

[0133] ;

[0134] Among them, the weight coefficient Dynamic adjustment based on the sensitivity analysis results of S4.

[0135] S54, performs adaptive optimization iterations, screens non-inferior solution sets in each generation, and dynamically adjusts the crossover / mutation probability; specifically, when the population diversity decreases by more than 20%, the probability of triggering mutation is increased to 0.1.

[0136] S55, evaluates the quality of structural parameters through the Monte Carlo method, performs process tolerance analysis on the optimal solution set, and eliminates solutions with sensitivity > 0.5dB / m / μm; quantifies the impact of manufacturing fluctuations on performance and screens robust design solutions.

[0137] S56, output the Pareto optimal solution set and three-dimensional performance cloud diagram, generate a parameter combination priority ranking table, and mark the manufacturability level.

[0138] Embodiment 2:

[0139] Combination Figure 3 As shown, the present invention also provides a low-loss cable connector without a resonance point, adopting the design method of the low-loss cable connector without a resonance point as in the first embodiment, the cable connector specifically comprises:

[0140] The outer shell is used to provide mechanical protection and heat dissipation, and is made of a high thermal conductivity composite material (not shown in the figure, located on the outer layer of the double insulation layer).

[0141] The double insulating layer 30 includes an inner layer 31 , an outer layer 32 , and a transition region between the inner layer 31 and the outer layer 32 .

[0142] The inner conductor 10 has a spiral gradient groove 20 disposed on its surface for impedance matching and signal transmission.

[0143] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for designing a low-loss cable connector without a resonance point, characterized in that: include: S1, designing a spiral gradient groove structure on the surface of the inner conductor of the cable connector, establishing a composite gradient impedance theoretical model of the connector, and defining a mapping relationship between geometric parameters of the spiral gradient groove of the inner conductor and the equivalent impedance Z (x); the geometric parameters include groove depth h, spiral angle θ and spiral period Λ; S2, constructing a dielectric constant gradient distribution model of the double insulating layer and setting the transition function between the inner layer and the outer layer; wherein the inner layer radius is R1 and the outer layer radius is R2; S3, solving the S parameters and electric field distribution of the connector through electromagnetic-thermal coupling finite element simulation, optimizing the spiral angle θ and the gradient index n, so that the voltage standing wave ratio VSWR is lower than the first preset value and the insertion loss IL does not exceed the second preset value; the S parameter is the electromagnetic loss; S4, establishing a quantitative model of conductor surface roughness and high-frequency loss, and determining a threshold range of surface roughness through calculation of the quantitative model; S5, global optimization of structural parameters (h, θ, Λ, n, R1, R2) based on multi-objective genetic algorithm, the objective function is min (w1⋅VSWR+w2⋅IL+w3⋅|Zin-50|), weight coefficients w1=0.5, w2=0.3, w3=0.2; S6, outputting a set of theoretical design parameter sets and a report collection of performance verification, wherein the report collection includes an impedance distribution curve, an electric field uniformity analysis result, and a full-band scattering parameter matrix.

2. The design method of a low-loss cable connector without resonance point according to claim 1, characterized in that: The inner layer is made of foamed polytetrafluoroethylene with a low dielectric constant, and its dielectric constant ε1=1.8; the outer layer is filled with a high dielectric constant boron nitride nanotube composite medium, and its dielectric constant ε2=3.

2.

3. The design method of a low-loss cable connector without resonance point according to claim 1, characterized in that: The S1 specifically includes: S11, construct a segmented spiral gradient groove on the axial surface of the inner conductor of the connector, wherein the spiral gradient groove consists of alternating deep groove segments and shallow groove segments, the depth of the deep groove segment h1=0.3mm, the depth of the shallow groove segment h2=0.1mm, the spiral angle θ changes linearly from 30° to 60°, and adjacent groove segments are connected by a smooth transition zone; S12, define the equivalent impedance distribution function Z(x) of the spiral gradient groove, and establish the mapping relationship between the groove depth h, the helix angle θ and the equivalent impedance through the mathematical method of exponential decay superposition sinusoidal modulation, where the groove depth h(x) decays with the axial position x according to the law of h(x)=h1+(h2-h1)e^(-αx), and the helix angle θ(x) and the axial projection length satisfy the linear constraint of tanθ(x)=k·x+b; S13, the spiral period Λ and the attenuation coefficient α are optimized by parametric scanning, and the impedance continuity is verified by finite element simulation, so that the impedance fluctuation ΔsZ between adjacent slot segments is ≤1Ω, and the full axial impedance deviation |Z(x)-50Ω| is ≤2Ω.

4. The design method of a low-loss cable connector without resonance point according to claim 3, characterized in that: The S13 further includes: S14, a chamfer structure is set at the bottom of the deep groove section, and the field-circuit collaborative simulation is used to calculate the smoothing effect of the chamfer on the electric field distribution, reducing the maximum field strength from 350V / m to below 220V / m; S15, based on parameter sensitivity analysis, determine the allowable range of key geometric parameters: helix angle θ∈[30°, 60°], helix period Λ∈[2mm, 5mm], attenuation coefficient α∈[0.1, 0.3]. If the allowable range is exceeded, an impedance mutation alarm is triggered; S16, generating a three-dimensional parameterized model and an impedance distribution curve of the spiral gradient groove, and outputting a design specification file.

5. The design method of a low-loss cable connector without resonance point according to claim 2, characterized in that: The S2 specifically includes: S21, determine the material composite system of the double insulation layer, the inner layer is a mixed material of foamed polytetrafluoroethylene and hollow glass microspheres, and the outer layer is a boron nitride nanotube / liquid silicone composite material. The nonlinear relationship between the dielectric constant and the component changes is determined through a material compounding experiment, thereby obtaining a material ratio table; S22, define the transition function of the dielectric constant gradient and establish the dielectric constant distribution equation with radial position r as the variable: ε(r)=ε1+(ε2-ε1)[(r-R1) / (R2-R1)]n Where n is the gradient index; S23, develop parametric modeling tools to import the dielectric constant distribution equation into 3D electromagnetic simulation software, generate solid models of insulating layers with non-uniform material properties, and verify the design goal of the peak electric field strength not exceeding 150 V / mm.

6. The design method of a low-loss cable connector without resonance point according to claim 5, characterized in that: The S23 further includes: S24, setting a periodic microstructure in the transition zone, wherein the periodic microstructure is specifically a honeycomb through-hole array with a pore diameter of 50 μm and a spacing of 100 μm, optimizing the microstructure morphology through finite element simulation, and obtaining a microstructure processing tolerance; S25, determining the polarization characteristics of the material composite system based on a dielectrophoresis experiment, modifying the dielectric constant theoretical model, and establishing a three-dimensional relationship map of component-dielectric constant-temperature to optimize the material ratio table; S26, output the design specification file of the double insulation layer, including the material ratio table, the allowable range of gradient index and the microstructure processing tolerance.

7. The design method of a low-loss cable connector without resonance point according to claim 6, characterized in that: The S3 specifically includes: S31, establish a coupled simulation model of the connector, and import the geometric parameters (h, θ, Λ) of the spiral gradient groove and the gradient distribution parameters (n, R1, R2) of the double insulation layer into the electromagnetic-thermal joint solver; S32, divide the adaptive grid in the target frequency band, use local encrypted grid for the spiral groove area, and set the boundary condition as radiation absorption boundary; S33, perform full-wave electromagnetic simulation to extract the S parameter matrix, calculate the voltage standing wave ratio VSWR and the insertion loss IL, and calculate the conductor loss power density distribution through the Joule heat model.

8. The design method of a low-loss cable connector without resonance point according to claim 6, characterized in that: The S33 also includes: S34, based on parameter sensitivity analysis, determine the influence weights of the spiral angle θ and the gradient index n on VSWR and IL, establish the parameter adjustment priority: θ>n>Λ>R1 / R2, optimize the spiral angle θ and the gradient index n through iteration, wherein the step size of the optimization iteration is set to θ±1°, n±0.2; S35, setting dynamic convergence criteria, when VSWR changes <0.01 for three consecutive iterations and IL changes <0.005dB / m, it is determined to be converged, the voltage standing wave ratio VSWR after convergence is lower than the first preset value, and the insertion loss IL does not exceed the second preset value.

9. The design method of a low-loss cable connector without resonance point according to claim 1, characterized in that: The S4 specifically includes: S41, using a three-dimensional surface profiler to measure the surface morphology of the conductor, extract the roughness amplitude Δs, the average spacing RSm and the fractal dimension D, and construct a non-Gaussian random surface model, where the fractal dimension D∈[2.3, 2.6]; S42, based on the modified skin effect theory, establish a rough surface AC resistance frequency-dependent model, define the functional relationship between high-frequency loss and roughness parameters (Δs, RSm, D), and calibrate the model coefficients by measuring the target frequency band 10-40GHz loss data with a vector network analyzer, and calibrate the rough surface AC resistance frequency-dependent model; S43, generating a plurality of groups of random rough surface samples based on Monte Carlo simulation, inputting the calibrated rough surface AC resistance frequency-dependent model to calculate the loss distribution at each frequency point, and determining the critical roughness threshold ΔS.

10. The design method of a low-loss cable connector without resonance points according to claim 1, characterized in that: The S5 specifically includes: S51, construct a multidimensional parameter space and define the optimization variable set: spiral groove depth h∈[0.1mm, 0.3mm], spiral angle θ∈[30°, 60°], spiral period Λ∈[2mm, 5mm], gradient index n∈[2.0, 3.0], inner radius R1=2.5mm±0.1mm, outer radius R2=4.0mm±0.2mm; S52, initializing the multi-objective genetic algorithm population, setting the population size, crossover probability, mutation probability, and loading the simulation database as an initial training set; S53, define the fitness function: F=0.5·VSWR+0.3·IL+0.2·|Zin-50Ω| Set up constraints: VSWR ≤ 1.1, IL (f = 20GHz) ≤ 0.15dB / m and Zin∈[48Ω, 52Ω]; S54, performs adaptive optimization iterations, screens non-inferior solution sets in each generation, and dynamically adjusts crossover / mutation probabilities; S55, evaluate the quality of structural parameters by Monte Carlo method, perform process tolerance analysis on the optimal solution set, and eliminate solutions with sensitivity > 0.5dB / m / μm; S56, output the Pareto optimal solution set and three-dimensional performance cloud diagram, generate a parameter combination priority ranking table, and mark the manufacturability level.

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