A high frequency cable test platform

Abstract

The application is suitable for the field of radio frequency and microwave test technology, and provides a high-frequency cable test platform, which comprises an interface contact impedance characterization module, which is used for acquiring the tightening torque, surface roughness and conductor material conductivity of a connector interface, calculating the dynamic contact resistance based on the coupling mechanism of contact mechanics and electromagnetic skin effect, and outputting the cascaded discontinuous impedance at the connector interface according to the dynamic contact resistance and the nominal characteristic impedance of the test platform interface. Through the cascaded cooperation of the interface contact impedance characterization module, the temperature drift correction module, the bending deformation reflection coefficient calculation module and the error de-embedding module, the dynamic resistance of the connector contact interface, the temperature dispersion effect of the insulating medium and the geometric eccentricity effect caused by the bending deformation of the cable are first included in a unified error model.

Description

Technical Field

[0001] This invention belongs to the field of radio frequency and microwave testing technology, and particularly relates to a high-frequency cable testing platform. Background Technology

[0002] High-frequency cable assemblies, as key interconnect components in radio frequency and microwave test systems, are widely used in communication equipment, radar systems, vector network analyzers, and automated test equipment.

[0003] Currently, the industry commonly uses scattering parameter measurement based on vector network analyzers to evaluate the performance of high-frequency cables. This method obtains the inherent electrical parameters of the cable by measuring the reflection and transmission coefficients at both ends of the cable and using standard calibration components for error correction. However, this traditional testing process faces multiple technical bottlenecks in practical engineering applications.

[0004] The actual conductivity of the connector interface is affected by multiple factors, including tightening torque, contact surface roughness, and conductor material conductivity. Under the high-frequency skin effect, the actual current-carrying cross section is drastically reduced, resulting in a significant frequency dependence of the contact resistance. Traditional calibration algorithms treat the connector interface as an ideal uniform transmission line, failing to effectively isolate the cascaded discontinuous impedance caused by the contact impedance, thus introducing parasitic system errors that are not inherent to the cable into the test results.

[0005] Temperature fluctuations in the testing environment can cause nonlinear drift in the characteristic impedance and dielectric constant of cables. The complex relative dielectric constant of the insulating medium exhibits dispersion with temperature changes, and the dielectric loss tangent also responds due to the temperature sensitivity of polarization relaxation strength. Current testing methods lack dynamic temperature correction mechanisms, making it difficult to guarantee the repeatability of measurement results at different times in industrial testing environments with large temperature differences. The bending deformation of cables in testing fixtures inevitably induces coaxial geometric eccentricity effects. The local characteristic impedance of the bending region deviates from the design value of the straight state, forming distributed reflection sources. Traditional testing schemes completely ignore the reflection component introduced by bending, incorrectly attributing it to the intrinsic attenuation of the cable or connector mismatch, interfering with the determination of the true transmission characteristics.

[0006] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0007] The purpose of this invention is to provide a high-frequency cable testing platform to solve the above-mentioned problems.

[0008] This invention is implemented as follows: a high-frequency cable testing platform, comprising:

[0009] The interface contact impedance characterization module is used to obtain the tightening torque, surface roughness and conductor material conductivity of the connector interface, calculate the dynamic contact resistance based on the coupling mechanism of contact mechanics and electromagnetic skin effect, and output the cascaded discontinuity impedance at the connector interface according to the dynamic contact resistance and the nominal characteristic impedance of the test platform interface.

[0010] The temperature drift correction module, connected to the interface contact impedance characterization module, is used to collect the real-time temperature of the test environment and obtain the reference relative permittivity, reference dielectric loss tangent, volume thermal expansion coefficient, and temperature response sensitivity coefficient of dielectric loss of the insulating medium. It reconstructs the complex relative permittivity under temperature dispersion and, combined with the reference characteristic impedance constant of the cable and the complex relative permittivity, outputs the temperature-corrected dynamic characteristic impedance and complex propagation constant of the cable.

[0011] The bending deformation reflection coefficient calculation module, connected to the temperature drift correction module, is used to obtain the outer diameter, measured bending radius and total length of the high-frequency cable, calculate the dynamic bending impedance based on the coaxial geometric eccentricity effect caused by bending deformation, and output the comprehensive dynamic reflection coefficient of the cable input end based on the dynamic bending impedance, the dynamic characteristic impedance, the complex propagation constant and the total length of the cable.

[0012] The error de-embedding module, connected to the bending deformation reflection coefficient calculation module, is used to receive the original scattering parameter matrix measured by the test instrument, perform signal flow graph decoupling and de-embedding operations on the original scattering parameter matrix according to the comprehensive dynamic reflection coefficient, and output the true input reflection coefficient and the true transmission scattering coefficient after removing the comprehensive parasitic errors of mechanical, thermal and electromagnetic components.

[0013] In a further technical solution, the dynamic contact resistance in the interface contact impedance characterization module is calculated based on the following physical relationship: Based on the skin effect, where the actual conductive cross-sectional area of ​​the contact interface decreases with increasing frequency, and combined with the plastic deformation behavior of the contact spots under applied tightening torque, the specific calculation steps for the dynamic contact resistance are as follows:

[0014] Divide 2 by the product of the test signal angular frequency, vacuum permeability and the conductor material reference conductivity, and then take the square root of the quotient to obtain the skin depth value; divide the microscopic average roughness of the contact surface by the skin depth value to obtain the first ratio, and then calculate 1 plus the square of the first ratio to obtain the skin effect correction factor.

[0015] The square root of the skin effect correction factor is taken, and then the square root is multiplied by the reference conductivity of the conductor material to obtain the equivalent conductivity correction term. The tightening torque is divided by the product of the dimensionless torque coefficient of the thread, the nominal diameter of the connector thread, and the Vickers hardness of the contact material, and the square root of the quotient is taken to obtain the contact spot plastic deformation term. The contact spot plastic deformation term is divided by the equivalent conductivity correction term, and the quotient is used as the dynamic contact resistance.

[0016] In a further technical solution, the cascaded discontinuous impedance is the sum of the dynamic contact resistance and the nominal characteristic impedance.

[0017] In a further technical solution, the complex relative permittivity in the temperature drift correction module is reconstructed based on the physical mechanism of the change in molecular density caused by the change in the volume of the insulating medium with temperature, and the change in the polarization relaxation intensity of the medium with temperature. The specific calculation steps are as follows:

[0018] The temperature change is obtained by subtracting the reference temperature from the measured ambient temperature; the real part correction factor is obtained by subtracting the product of the volume thermal expansion coefficient and the temperature change; the real part of the complex relative permittivity is obtained by multiplying the real part correction factor by the reference relative permittivity.

[0019] The imaginary part correction factor is obtained by multiplying the temperature response sensitivity coefficient of the dielectric loss by the temperature change; the imaginary part coefficient of the complex relative permittivity is obtained by multiplying the imaginary part correction factor by the reference dielectric loss tangent.

[0020] By combining the real and imaginary parts, with the coefficient before the imaginary unit being negative, the complex relative permittivity under temperature coupling is obtained.

[0021] A further technical solution is that the dynamic characteristic impedance of the cable and the complex propagation constant are calculated based on the cable's reference characteristic impedance constant and complex relative permittivity:

[0022] The dynamic characteristic impedance of the cable is obtained by correcting the reference characteristic impedance constant, which is determined by the physical geometry of the cable, for dielectric temperature dispersion. The specific calculation steps are as follows:

[0023] The first step is to calculate the difference between the measured ambient temperature and the reference temperature. The second step is to calculate the product of the volumetric thermal expansion coefficient and the difference. The third step is to calculate the result by subtracting the product, which is used as the temperature correction factor. The fourth step is to calculate the product of the reference relative permittivity and the temperature correction factor, and then take the square root of the product. The fifth step is to divide the reference characteristic impedance constant by the square root, and the quotient is used as the dynamic characteristic impedance of the cable after temperature change correction.

[0024] The complex propagation constant is calculated based on the complex relative permittivity and the speed of light in vacuum. Specifically, the quotient obtained by dividing the angular frequency of the test signal by the speed of light in vacuum is multiplied by the square root of the complex relative permittivity, and the product is then multiplied by the imaginary unit.

[0025] A further technical solution involves using the bending deformation reflection coefficient calculation module to calculate the dynamic bending impedance based on the physical mechanism that causes geometric eccentricity of the inner and outer conductors during coaxial cable bending, resulting in a deviation of the local characteristic impedance from the original characteristic impedance. Specifically:

[0026] The difference between multiplying the temperature-corrected dynamic characteristic impedance of the cable by one and subtracting the following ratio is calculated: the numerator of this ratio is the square of the high-frequency cable outer diameter divided by eight times the measured bending radius, and the denominator is twice the square of the high-frequency cable outer diameter.

[0027] A further technical solution is that the comprehensive dynamic reflection coefficient is based on the attenuation and phase shift characteristics of the transmission line termination, and is determined by the degree of mismatch between the dynamic bending impedance and the dynamic characteristic impedance at the bending interface, as well as the propagation attenuation and phase change of the signal along the cable length direction, specifically:

[0028] First, calculate the reflection coefficient at the curved interface. Specifically, use the difference between the dynamic bending impedance and the dynamic characteristic impedance as the numerator, and the sum of the dynamic bending impedance and the dynamic characteristic impedance as the denominator. Divide the numerator by the denominator to obtain the interface reflection coefficient.

[0029] Next, calculate the propagation attenuation and phase change terms. Specifically, take the product of the complex propagation constant and twice the total cable length as an exponential function with the natural constant as the base. The value of this exponential function is a negative power.

[0030] Finally, the interface reflection coefficient is multiplied by the propagation attenuation and phase change terms to obtain the comprehensive dynamic reflection coefficient.

[0031] In a further technical solution, in the error de-embedding module, the true input reflection coefficient and the true transmitted scattering coefficient are extracted from the original scattering parameter matrix through the following signal flow graph operation:

[0032] The calculation method for the true input reflection coefficient is as follows: the difference between the original input reflection coefficient measured by the testing instrument and the comprehensive dynamic reflection coefficient is used as the numerator, and the product of the original output reflection coefficient and the comprehensive dynamic reflection coefficient is subtracted from the numerator as the denominator. The quotient obtained by dividing the numerator by the denominator is used as the true input reflection coefficient after de-embedding and reconstruction.

[0033] The true transmission scattering coefficient is calculated as follows: First, subtract the square of the comprehensive dynamic reflection coefficient from 1 to obtain the first factor. Then, subtract the product of the original output reflection coefficient and the comprehensive dynamic reflection coefficient from 1 to obtain the second factor. Divide the first factor by the second factor, and multiply the quotient by the original forward transmission coefficient to obtain the reconstructed true transmission scattering coefficient.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] This invention, through the cascaded collaboration of an interface contact impedance characterization module, a temperature drift correction module, a bending deformation reflection coefficient calculation module, and an error de-embedding module, for the first time incorporates the dynamic resistance of the connector contact interface, the temperature dispersion effect of the insulating medium, and the geometric eccentricity effect caused by cable bending deformation into a unified error model. Based on signal flow graph theory, it performs comprehensive de-embedding calculations, effectively eliminating mechanical, thermal, and electromagnetic parasitic errors, and outputting the input reflection coefficient and transmission scattering coefficient that truly reflect the intrinsic performance of the cable. This solves the problem of indistinguishable parasitic errors in traditional testing, and significantly improves testing accuracy.

[0036] The interface contact impedance characterization module comprehensively considers the reduction of conductive cross-sectional area with frequency under the skin effect and the plastic deformation behavior of contact spots under tightening torque. By introducing skin depth correction factor and contact spot plastic deformation term, it establishes a quantitative physical relationship between dynamic contact resistance and signal frequency, tightening torque, surface roughness and material parameters. This overcomes the frequency indifference defect of traditional fixed contact resistance model and makes the calculation of cascaded discontinuous impedance of connectors more consistent with high-frequency actual working conditions.

[0037] The temperature drift correction module reconstructs the temperature-dependent complex relative permittivity based on the change in molecular density caused by the thermal expansion of the insulating medium and the temperature sensitivity of the polarization relaxation intensity. Based on this, it dynamically corrects the characteristic impedance and complex propagation constant of the cable, achieving synchronous temperature compensation for the dielectric loss tangent and the real part of the dielectric constant. Even in industrial test sites with large temperature differences, it can maintain the repeatability and consistency of measurement results and significantly reduce the interference of ambient temperature fluctuations on test data.

[0038] The bending deformation reflection coefficient calculation module is based on the coaxial geometric eccentricity effect. It uses the measured bending radius and cable outer diameter to accurately calculate the dynamic bending impedance and combines the transmission line attenuation phase shift characteristics to map the reflection from the bending interface to the cable input end, forming a comprehensive dynamic reflection coefficient. The error de-embedding module uses this coefficient to decouple the original scattering parameters from the signal flow graph, effectively eliminating the false reflection components introduced by bending and avoiding them from being misjudged as cable intrinsic attenuation or connector mismatch. This provides true and reliable transmission scattering parameters and provides an accurate basis for the performance evaluation of high-frequency cables. Attached Figure Description

[0039] Figure 1This is a schematic diagram of the overall structure of the high-frequency cable testing platform;

[0040] Figure 2 Schematic diagram of the interface contact impedance characterization module;

[0041] Figure 3 This is a schematic diagram of the temperature drift correction module;

[0042] Figure 4 This is a schematic diagram of the module for calculating the reflection coefficient of bending deformation.

[0043] Figure 5 A schematic diagram of the error embedding module. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0045] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0046] like Figures 1-5 As shown, a high-frequency cable testing platform provided in one embodiment of the present invention includes:

[0047] The interface contact impedance characterization module acquires the tightening torque, surface roughness, and conductor material conductivity of the connector interface. For example, tightening torque can be monitored or recorded in real-time using a tool with a torque sensor during connector tightening; surface roughness can be obtained through pre-measurement or sampling of the connector contact surface using an optical profilometer or contact roughness meter; conductor material conductivity can be found in the material supplier's datasheet or measured using a conductivity meter. Based on these acquired parameters, the module calculates the dynamic contact resistance using the coupling mechanism of contact mechanics and the electromagnetic skin effect. For example, an empirical model can be established that correlates the actual conductive area of ​​the contact interface with tightening torque and surface roughness, considering the effect of the current skin effect at high frequencies leading to a reduction in effective conductive area, thereby estimating the dynamic contact resistance. Subsequently, the module outputs the cascaded discontinuity impedance at the connector interface based on the calculated dynamic contact resistance and the nominal characteristic impedance of the test platform interface. For example, the dynamic contact resistance can be considered as a small resistor connected in series on an ideal transmission line, thus calculating the impact of this discontinuity on signal transmission.

[0048] The temperature drift correction module is connected to the aforementioned interface contact impedance characterization module. This module is used to acquire the real-time temperature of the test environment. For example, the ambient temperature can be continuously monitored by deploying high-precision temperature sensors (such as thermocouples or platinum resistance thermometers) near the test platform. Simultaneously, this module acquires the reference relative permittivity, reference dielectric loss tangent, volumetric thermal expansion coefficient, and temperature response sensitivity coefficient of the dielectric loss of the insulating medium. These parameters are typically obtained by pre-calibrating the cable insulation material through dielectric performance and thermal expansion tests and stored in the platform's database. Based on these parameters, the module can reconstruct the complex relative permittivity under temperature dispersion. For example, polynomial fitting or a function based on a physical model can be used to describe the variation of the dielectric constant and dielectric loss tangent with temperature, thereby obtaining the complex relative permittivity at the current real-time temperature. Subsequently, the module combines the cable's reference characteristic impedance constant with this complex relative permittivity to output the temperature-corrected dynamic characteristic impedance and complex propagation constant of the cable.

[0049] The bending deformation reflection coefficient calculation module is connected to the aforementioned temperature drift correction module. This module is used to obtain the outer diameter, measured bending radius, and total length of the high-frequency cable. For example, the outer diameter can be obtained from the cable specification sheet; the measured bending radius can be measured using a simple mechanical measuring tool on a testing fixture, or estimated by analyzing the profile of the bent cable using image recognition technology; the total length of the cable can be measured using a measuring tape or a laser rangefinder. Based on the coaxial geometric eccentricity effect caused by bending deformation, this module can calculate the dynamic bending impedance. For example, a geometric model can be established that correlates the relative eccentricity between the inner and outer conductors during cable bending with the bending radius, thereby estimating the local characteristic impedance change in the bending region. Subsequently, based on the dynamic bending impedance, the aforementioned dynamic characteristic impedance, the aforementioned complex propagation constant, and the total length of the cable, the module outputs the comprehensive dynamic reflection coefficient at the cable input end.

[0050] The error de-embedding module is connected to the aforementioned bending deformation reflection coefficient calculation module. This module receives the raw scattering parameter matrix measured by the testing instrument. For example, this module can communicate with a vector network analyzer via a standard interface (such as GPIB, USB, or Ethernet) to obtain the raw S-parameter measurement results in real time. Based on the aforementioned comprehensive dynamic reflection coefficient, this module can perform signal flow graph decoupling and de-embedding operations on the raw scattering parameter matrix. For example, a signal flow graph model including the connector interface, cable body, and bending region can be constructed, and the calculated comprehensive dynamic reflection coefficient can be used as a key parameter in this model to correct the raw S-parameters using a signal flow graph algorithm. Thus, this module outputs the true input reflection coefficient and true transmitted scattering coefficient after removing mechanical, thermal, and electromagnetic parasitic errors. These corrected parameters can more accurately reflect the electrical performance of the high-frequency cable itself.

[0051] In this embodiment, the aforementioned high-frequency cable testing platform provides a systematic solution by integrating multiple functional modules, including interface contact impedance characterization, temperature drift correction, bending deformation reflection coefficient calculation, and error de-embedding. Compared to existing methods that rely solely on standard calibration components for error correction, this platform can more comprehensively and deeply identify and quantify the combined mechanical, thermal, and electromagnetic parasitic errors introduced during testing by connector contact, ambient temperature, and cable bending deformation. For example, in the above example, traditional methods directly use the raw S-parameters as the cable's performance indicators, without distinguishing how much of it is caused by improper connector tightening, ambient temperature changes, or cable bending. This platform, however, can characterize and comprehensively correct these influencing factors one by one, thereby outputting the cable's true electrical characteristics, unaffected by the external environment. Therefore, this platform significantly improves the accuracy and repeatability of high-frequency cable test results, providing a more reliable basis for the performance evaluation of high-frequency cable assemblies and effectively solving the technical problems of low reliability and poor repeatability of test data in existing technologies.

[0052] In a preferred embodiment of the present invention, the dynamic contact resistance in the interface contact impedance characterization module is calculated based on the following physical relationship:

[0053] Based on the skin effect, where the actual conductive cross-sectional area of ​​the contact interface decreases with increasing frequency, and considering the plastic deformation behavior of the contact spot under applied tightening torque, the dynamic contact resistance satisfies the following relationship with the angular frequency of the test signal, the tightening torque, the surface roughness, the reference conductivity of the conductor material, the vacuum permeability, the dimensionless torque coefficient of the thread, the nominal diameter of the connector thread, and the Vickers hardness of the contact material:

[0054]

[0055] Wherein, the dimensionless torque coefficient of the thread, the Vickers hardness, the reference conductivity of the conductor material, and the vacuum permeability are all known material properties or physical constants;

[0056] In the above formula, Indicates dynamic contact resistance; Indicates the angular frequency of the test signal. Indicates the tightening torque of the connector; This represents the average microscopic roughness of the contact surface. The reference conductivity of a conductor material; Indicates the permeability of free space; The dimensionless torque coefficient representing the thread; Indicates the nominal diameter of the connector thread; This indicates the Vickers hardness of the material in contact with it.

[0057] In this embodiment, the calculation of the physical relationship of dynamic contact resistance aims to accurately quantify the resistance at the interface of the high-frequency cable connector, which is a key factor affecting signal integrity. This can be achieved by integrating a dedicated mathematical processor or digital signal processor within the interface contact impedance characterization module. This processor is pre-programmed with the aforementioned physical relationship formula and can receive input parameters and perform calculations in real time. Alternatively, the calculation function can be performed by a general-purpose computer or embedded system connected to the interface contact resistance characterization module, running specific software algorithms to analyze and calculate the dynamic contact resistance.

[0058] The skin effect refers to the phenomenon where, under high-frequency current, current tends to flow along the surface of a conductor, resulting in a reduction in the actual conductive cross-sectional area. Considering the skin effect in the calculation of dynamic contact resistance can more accurately reflect the loss of high-frequency signals at the connector contact interface. This can be achieved by introducing frequency-related terms into the formula, for example, by calculating the skin depth and combining it with the geometry of the contact spot to correct for the effective conductive area.

[0059] The plastic deformation behavior of contact spots refers to the formation of microscopic contact spots at the contact interface of a connector under tightening torque. These spots undergo plastic deformation, thus affecting the actual contact area and contact resistance. Incorporating this plastic deformation behavior into the computational model allows for a more accurate reflection of the impact of tightening torque on contact resistance. This can be achieved by introducing parameters related to tightening torque and material hardness to characterize the formation and degree of contact spot deformation, for example, by modifying models based on Hertzian contact theory or more complex elastoplastic contact models.

[0060] Test signal angular frequency The instantaneous angular frequency of a high-frequency test signal is a key parameter affecting the skin effect and dielectric loss. It can be obtained directly by reading the settings of the test instrument (such as a vector network analyzer), or by measuring the period or frequency of the test signal and then converting the result.

[0061] Connector tightening torque This indicates the rotational torque applied during connector installation, which directly affects the pressure at the contact interface and the actual contact area. It can be obtained either through real-time measurement using a specialized tool with a torque sensor during connector installation, or by inputting a preset tightening torque value.

[0062] Microscopic average roughness of the contact surface This is a statistical measure representing the degree of microscopic unevenness on the connector contact surface, which affects the formation and distribution of contact spots. It can be obtained by pre-measuring and characterizing the connector contact surface using precision measuring equipment such as optical profilometers and atomic force microscopes, or by setting typical values ​​based on the connector material and manufacturing process.

[0063] Reference conductivity of conductor materials The conductivity value indicates the ability of a conductor material to conduct electricity under DC or low-frequency conditions, and is a fundamental parameter for calculating the skin effect and resistive loss. It can be obtained by consulting material handbooks or supplier datasheets to obtain standard values, or by performing conductivity tests such as the four-probe method on conductor material samples.

[0064] Vacuum permeability It is a physical constant representing the magnetic permeability in a vacuum. It is obtained by directly using known physical constant values, such as 4π × 10⁻⁶. -7 H / m.

[0065] Dimensionless torque coefficient of thread It is an empirical coefficient related to thread geometry, friction coefficient, etc., used to convert tightening torque into axial preload. It can be obtained by consulting relevant engineering manuals and standards to obtain typical values, or by calibrating actual values ​​for different thread types and material combinations through experiments.

[0066] Connector thread nominal diameter The nominal diameter of the connector thread is a geometric parameter used to calculate the contact area and stress. It can be obtained by consulting the connector product specification sheet or design drawings, or by actual measurement using measuring tools such as calipers or micrometers.

[0067] Vickers hardness of contact materials This indicates the hardness of the connector contact material, which affects the plastic deformation behavior of the contact spots. It can be obtained by consulting material handbooks or supplier datasheets to obtain standard values, or by testing material samples using a Vickers hardness tester.

[0068] In a preferred embodiment of the present invention, the cascaded discontinuous impedance is the sum of the dynamic contact resistance and the nominal characteristic impedance:

[0069]

[0070] in, Indicates the cascaded discontinuity impedance at the connector interface; This indicates the nominal characteristic impedance of the test platform interface.

[0071] In this embodiment, the discontinuous impedance is connected. This refers to the overall impedance change at the connector interface due to physical contact and electrical connection. It includes not only the resistive effect of the contact points themselves but also the inherent impedance characteristics of the test platform interface. The concept is to provide a comprehensive parameter to quantify the degree of impedance matching or mismatch at this interface for high-frequency signal transmission paths. This cascaded discontinuity impedance... It can be characterized in various ways, such as through time-domain reflectometry or through theoretical model calculation. Dynamic contact resistance It is calculated based on the above physical relationships and reflects the resistive characteristics of the connector contact surface under specific mechanical and electromagnetic conditions. It is an important component of interface impedance discontinuity. Nominal characteristic impedance This refers to the nominal impedance value of the test platform interface, such as 50 ohms or 75 ohms, which represents the ideal transmission line impedance on which the test system design is based.

[0072] The solution in this application is to achieve dynamic contact resistance Nominal characteristic impedance of the interface with the test platform A simple yet effective superposition is used to construct the cascaded discontinuity impedance at the connector interface. Dynamic contact resistance It accurately captures the actual resistance loss at the connector interface caused by factors such as tightening torque, surface roughness, and skin effect. Nominal characteristic impedance. This represents the reference impedance of the test platform interface. By adding these two, the scheme can comprehensively reflect the total impedance discontinuity encountered by high-frequency signals when passing through the connector interface. This combination expands the characterization of interface impedance from a single contact resistance to a holistic view including the system reference impedance, thereby enabling a more accurate assessment of the impact of the connector interface on signal reflection and transmission loss, and providing a more precise input for subsequent error de-embedding calculations.

[0073] In a preferred embodiment of the present invention, the complex relative permittivity in the temperature drift correction module is reconstructed based on the physical mechanisms of changes in molecular density caused by temperature variations in the volume of the insulating medium and changes in the polarization relaxation intensity of the medium with temperature variations.

[0074]

[0075] The volume thermal expansion coefficient and the temperature response sensitivity coefficient of the dielectric loss are obtained through pre-testing and calibration of the insulating dielectric material;

[0076] In the above formula, Indicates the complex relative permittivity under temperature coupling; Indicates the relative permittivity of the dielectric reference; Indicates the coefficient of thermal expansion of the volume; Indicates the measured ambient temperature; Indicates the reference temperature; Represents the imaginary unit; Indicates the tangent of the reference dielectric loss angle; This represents the temperature response sensitivity coefficient for dielectric loss.

[0077] In this embodiment, the complex relative permittivity is a key parameter describing the polarization response and energy loss of the dielectric under an electric field. Its imaginary part is related to dielectric loss, while its real part is related to energy storage. The volume of the insulating dielectric expands or contracts with temperature changes, leading to changes in the molecular density within the dielectric. Changes in molecular density directly affect the number of polarizable molecules per unit volume, thus affecting the overall polarizability of the dielectric, i.e., the real part of the relative permittivity. Furthermore, the polarization relaxation processes within the dielectric (e.g., dipole polarization, interfacial polarization, etc.) are highly sensitive to temperature. Increased temperature typically accelerates the thermal motion of molecules and reduces intermolecular forces, thereby altering the polarization relaxation time and affecting the loss characteristics of the dielectric, i.e., the imaginary part of the relative permittivity. By considering these two physical mechanisms in a coupled manner, this application can more comprehensively and accurately reflect the true dielectric properties of the insulating dielectric at different temperatures.

[0078] Coefficient of thermal expansion The volumetric thermal expansion coefficient is a physical quantity that measures the degree to which a material's volume expands or contracts with changes in temperature. For insulating media, this expansion or contraction directly leads to changes in the intermolecular spacing and molecular density within the medium. When reconstructing the complex relative permittivity, the volumetric thermal expansion coefficient is used to quantify the effect of temperature changes on the molecular density of the medium, thereby correcting the real part of the relative permittivity. This coefficient can be obtained through various experimental methods. For example, a thermomechanical analyzer (TMA) can be used to measure the dimensional changes of the material at different temperatures, and then the volumetric thermal expansion coefficient can be calculated; alternatively, the density of the medium at different temperatures can be measured using a densitometer, and the volumetric thermal expansion coefficient can be derived using the principle of mass conservation.

[0079] Temperature response sensitivity coefficient of dielectric loss This coefficient characterizes the sensitivity of the dielectric loss tangent of the insulating medium to temperature changes. Dielectric loss is a crucial component of transmission loss in high-frequency cables, and its magnitude directly affects signal attenuation. This coefficient quantifies the impact of temperature changes on the dielectric polarization relaxation strength and loss characteristics, thereby correcting the imaginary part of the complex relative permittivity. Obtaining this coefficient typically requires specialized dielectric property testing of the insulating medium material. For example, the dielectric loss tangent can be measured at different temperatures using a dielectric spectrometer, and then the temperature response sensitivity coefficient of the dielectric loss can be extracted through data fitting or differential analysis. Pre-test calibration refers to determining the bulk thermal expansion coefficient and the temperature response sensitivity coefficient of the dielectric loss of the insulating medium material through precise measurements and experiments in a laboratory environment before actual high-frequency cable testing. This usually involves placing the insulating medium sample under test in a precisely controlled temperature environment and using specialized testing equipment (such as a thermomechanical analyzer and dielectric spectrometer) to perform multi-point measurements of its physical dimensions and dielectric properties. By analyzing and fitting these measurement data, a mathematical model of the relationship between these parameters and temperature can be established, thereby obtaining accurate coefficient values. This pre-calibration ensures that the temperature drift correction module can perform calculations based on accurate material parameters during actual testing, improving the reliability and accuracy of the correction.

[0080] The temperature drift correction module of this application reconstructs the complex relative permittivity by introducing the physical mechanisms of changes in molecular density caused by temperature variations in the volume of the insulating dielectric and changes in the dielectric polarization relaxation intensity with temperature. Specifically, the module first acquires the real-time temperature of the test environment. And obtain the reference relative permittivity of the insulating medium. Reference dielectric loss tangent Coefficient of thermal expansion and the temperature response sensitivity coefficient of dielectric loss .

[0081] Among them, the coefficient of thermal expansion of volume Temperature response sensitivity coefficient of dielectric loss This is obtained through pre-testing and calibration of the insulating dielectric material. Based on the above parameters, the temperature drift correction module uses the provided mathematical model to calculate the temperature at the current measured ambient temperature. The complex relative permittivity under the following conditions The real part of the formula This reflects the effect of dielectric volume expansion or contraction on molecular density, thus correcting the real part of the relative permittivity; the imaginary part term... This reflects the effect of temperature on the polarization relaxation strength and loss characteristics of the dielectric, thus correcting the imaginary part of the relative permittivity.

[0082] In this way, the temperature drift correction module can accurately reconstruct the complex relative permittivity considering the temperature dispersion effect. Subsequently, this module combines the cable's reference characteristic impedance constant with the reconstructed complex relative permittivity to output the temperature-corrected dynamic characteristic impedance and complex propagation constant of the cable. These corrected parameters serve as input to the subsequent bending deformation reflection coefficient calculation module, ensuring more accurate and reliable evaluation of the electrical performance of high-frequency cables under different temperature conditions. Compared to schemes that only consider connector interface impedance, this application, by introducing the influence of temperature on the permittivity, enables the entire test platform to more comprehensively simulate the complex electrical behavior of high-frequency cables in actual working environments, significantly improving the realism and accuracy of the test results.

[0083] In a preferred embodiment of the present invention, the dynamic characteristic impedance of the cable and the complex propagation constant are calculated based on the cable reference characteristic impedance constant and the complex relative permittivity:

[0084] The dynamic characteristic impedance of the cable is obtained by correcting the reference characteristic impedance constant, which is determined by the physical geometry of the cable, for dielectric temperature dispersion:

[0085]

[0086] The complex propagation constant is calculated based on the complex relative permittivity and the speed of light in vacuum:

[0087]

[0088] In the above formula, This represents the dynamic characteristic impedance of the cable after temperature change correction. This represents the reference characteristic impedance constant of the cable in a vacuum environment; Represents the complex propagation constant; This represents the speed of light in a vacuum.

[0089] In this embodiment, the dynamic characteristic impedance of the cable Characteristic impedance refers to the impedance exhibited by a high-frequency cable at a specific operating temperature. Its function is to accurately characterize the signal transmission matching characteristics of the cable under actual temperature conditions, and it is a key parameter for evaluating signal reflection and transmission efficiency. This impedance dynamically adjusts with temperature changes to reflect changes in the dielectric properties.

[0090] Cable reference characteristic impedance constant Dynamic characteristic impedance refers to the inherent characteristic impedance of a high-frequency cable under ideal or standard conditions (such as a vacuum environment or a specific reference temperature), determined by its physical geometry. This constant serves as a reference value for calculating dynamic characteristic impedance and can be obtained through theoretical calculations of cable design parameters or through precise measurement and calibration of the cable under standard test conditions.

[0091] Dielectric temperature dispersion correction refers to the process of adjusting the characteristic impedance of a cable based on the variation of the dielectric constant of the insulating medium with temperature. Its purpose is to eliminate or reduce the influence of ambient temperature changes on the measurement or calculation results of the cable's characteristic impedance, making the calculated characteristic impedance closer to the true value of the cable at its actual operating temperature. This correction can be achieved by looking up tables in a pre-established database of dielectric material temperature characteristics, or by dynamically calculating the temperature in real time and combining it with a temperature response model of the material.

[0092] Complex propagation constant The complex propagation constant is a physical quantity that describes the attenuation and phase changes of a high-frequency signal during its transmission along a cable. Its function is to comprehensively evaluate the transmission loss, propagation speed, and time delay of the signal in the cable, making it an important indicator for analyzing cable transmission performance. The complex propagation constant consists of a real part (attenuation constant) and an imaginary part (phase constant), reflecting the attenuation of the signal amplitude and the lag in phase, respectively.

[0093] Complex relative permittivity The relative permittivity of an insulating medium at specific temperatures and frequencies comprises a real part (dielectric constant) and an imaginary part (dielectric loss). Its function is to comprehensively reflect the energy storage capacity and energy loss characteristics of the medium, and it forms the basis for calculating the propagation constant and characteristic impedance of cables. This parameter can be reconstructed using a physical model of the dielectric material combined with measured temperature and frequency, or obtained through broadband dielectric spectroscopy measurement techniques.

[0094] speed of light in vacuum It refers to the speed of electromagnetic waves in a vacuum and is a fundamental physical constant. Its function is to serve as a benchmark for calculating the speed and propagation constant of electromagnetic waves in a medium, and it is a core parameter in electromagnetic field theory.

[0095] This application's solution combines the complex relative permittivity output by the temperature drift correction module with the cable's reference characteristic impedance constant, achieving accurate calculation of the cable's dynamic characteristic impedance and complex propagation constant. Specifically, the calculation of the cable's dynamic characteristic impedance first uses the reference characteristic impedance constant determined by the cable's physical geometry as a basis, and then introduces dielectric temperature dispersion correction. This correction mechanism utilizes the temperature-affected dielectric constant reconstructed by the temperature drift correction module, allowing the calculated characteristic impedance to dynamically reflect the cable's true electrical characteristics under different ambient temperatures. Simultaneously, the calculation of the complex propagation constant directly utilizes the complex relative permittivity provided by the temperature drift correction module, combined with the speed of light in a vacuum, to comprehensively characterize the signal attenuation and phase change during propagation in the cable. This method of calculating the cable's dynamic characteristic impedance and complex propagation constant based on temperature-corrected dielectric parameters enables the subsequent bending deformation reflection coefficient calculation module to obtain more accurate cable electrical parameters. This allows for more effective removal of mechanical, thermal, and electromagnetic parasitic errors in the error de-embedding module, ultimately outputting more realistic cable scattering parameters.

[0096] In a preferred embodiment of the present invention, the dynamic bending impedance in the bending deformation reflection coefficient calculation module is calculated based on the physical mechanism that the inner and outer conductors of the coaxial cable become geometrically eccentric during bending, causing the local characteristic impedance to deviate from the original characteristic impedance.

[0097]

[0098] The bending radius is obtained in real time by a displacement sensor or a visual measurement device installed on a high-frequency cable testing fixture.

[0099] In the above formula, This represents the dynamic bending resistance after eccentric deformation occurs in the mechanical bending region. Indicates the outer diameter of the high-frequency cable; This indicates the measured bending radius of the cable.

[0100] In this embodiment, the dynamic bending impedance is calculated based on the physical mechanism by which the geometric eccentricity of the inner and outer conductors of a coaxial cable causes a deviation of the local characteristic impedance from its original characteristic impedance when the cable is bent. Dynamic bending impedance refers to the deformation of the internal coaxial structure of a high-frequency cable under external bending force, resulting in a change in the relative position between the inner and outer conductors, and consequently causing the local characteristic impedance to deviate from its original design value or the characteristic impedance under straight-line conditions. This deviation is dynamic because it depends on the degree and location of the bend. When a coaxial cable bends, the inner and outer conductors become geometrically eccentric, specifically, the inner conductor is no longer precisely located on the central axis of the outer conductor. This eccentricity alters the electric and magnetic field distribution on the cable cross-section, thus affecting the capacitance and inductance per unit length of the cable, ultimately leading to a change in the local characteristic impedance. The physical mechanism for calculating this dynamic bending impedance can be derived based on electromagnetic field theory by analyzing the capacitance and inductance of the eccentric coaxial line. For example, the finite element method can be used to model the cable cross-section under different bending radii, calculate its capacitance and inductance, and then derive the characteristic impedance. Alternatively, an empirical formula or approximate model can be used to establish a mathematical relationship between the geometric eccentricity and the change in characteristic impedance.

[0101] The formula for calculating dynamic bending resistance provides a specific method for quantifying dynamic bending resistance. Indicates at a specific temperature and bending radius The dynamic bending resistance after eccentric deformation occurs in the mechanical bending region. This is the temperature-corrected dynamic characteristic impedance of the cable, output by the aforementioned temperature drift correction module. It represents the characteristic impedance of the cable in a straight state, taking into account the effects of temperature. The correction term in the formula... It is specifically designed to characterize impedance changes caused by bending deformation. This indicates the outer diameter of a high-frequency cable and is an inherent geometric parameter of the cable. The measured cable bending radius is a key parameter for measuring the degree of cable bending. This formula calculates the dynamic bending impedance under bending conditions by multiplying the dynamic characteristic impedance under straight conditions by a correction factor based on the cable's outer diameter and bending radius. It intuitively reflects the physical phenomenon that the greater the degree of bending, the more significantly the impedance deviates from the original value.

[0102] Furthermore, the bending radius is acquired in real time using a displacement sensor or a vision measurement device mounted on a high-frequency cable testing fixture. Real-time acquisition of the bending radius is crucial for accurately calculating dynamic bending impedance. A displacement sensor can be mounted on the testing fixture and, by measuring the displacement of a specific point on the cable during bending, combined with the fixture's geometry, indirectly calculate the cable's bending radius. For example, a linear displacement sensor or rotary encoder can be used to monitor the fixture's movement, thereby inferring the cable's bending state. A vision measurement device can directly measure the cable's bending profile using image processing technology. For instance, a high-resolution camera can be used to capture images of the cable's bending area, and then edge detection, curve fitting, and other algorithms can be used to accurately extract the cable's bending radius. Additionally, a laser scanner or 3D point cloud technology can be used to acquire 3D geometric data of the cable's bending area, thereby calculating a more accurate bending radius.

[0103] The bending deformation reflection coefficient calculation module of this application receives the temperature-corrected dynamic characteristic impedance of the cable from the temperature drift correction module. and complex propagation constant Then, the outer diameter of the high-frequency cable is first obtained in real time. and measured bending radius In conjunction with the total cable length L, the dynamic bending impedance of the cable under bending conditions can be accurately calculated. Specifically, based on the physical mechanism that the geometric eccentricity of the inner and outer conductors causes the local characteristic impedance to deviate from the original characteristic impedance when a coaxial cable is bent, this module uses a provided mathematical model to adjust the temperature-corrected dynamic characteristic impedance of the cable. As a reference, by introducing a value related to the cable outer diameter and measured bending radius By applying relevant correction factors, the dynamic bending impedance of the bending region is calculated. This calculation method allows for the accurate quantification of local impedance changes in the cable under different degrees of bending. Subsequently, the module utilizes the calculated dynamic bending impedance... Dynamic characteristic impedance Complex propagation constant In addition to the total cable length L, considering the reflection caused by impedance mismatch at the bending interface, as well as the signal propagation attenuation and phase change along the cable length, the final output cable input end comprehensive dynamic reflection coefficient is calculated. .

[0104] In this way, the proposed solution can accurately incorporate the mechanical bending deformation effect of the cable into the scattering parameter test model of the high-frequency cable. This provides a more accurate input for the subsequent error de-embedding module, taking into account multiple parasitic error sources such as connector interface, temperature drift and cable bending deformation, thus significantly improving the authenticity and reliability of the high-frequency cable test results.

[0105] In a preferred embodiment of the present invention, the integrated dynamic reflection coefficient is based on the attenuation and phase shift characteristics of the transmission line termination, and is determined by the degree of mismatch between the dynamic bending impedance and the dynamic characteristic impedance at the bending interface, as well as the propagation attenuation and phase change of the signal along the cable length direction.

[0106]

[0107] In the above formula, Indicates the overall dynamic reflection coefficient; This indicates the total length of the high-frequency cable.

[0108] In this embodiment, the transmission line termination attenuation and phase shift characteristics refer to the physical phenomenon that when an electromagnetic wave propagates in a transmission line, its amplitude decreases due to energy loss (attenuation), and its phase changes due to propagation distance and medium characteristics (phase shift). This characteristic is unavoidable when high-frequency signals are transmitted in actual cables, and it directly affects signal integrity and latency. This characteristic can be accurately described by the complex propagation constant of the transmission line, which includes the attenuation constant and the phase constant, and is a key parameter for evaluating transmission line performance. The degree of mismatch between dynamic bending impedance and dynamic characteristic impedance at the bending interface refers to the difference between the characteristic impedance of the bent region (i.e., dynamic bending impedance) and the characteristic impedance of the unbent part of the cable (i.e., dynamic characteristic impedance) when the local geometry of the high-frequency cable changes due to mechanical bending. This impedance discontinuity causes the incident signal to be reflected at the bending interface. The degree of mismatch is usually quantified by the reflection coefficient, which is calculated based on the reflection formula for impedance discontinuities in transmission line theory, reflecting the proportion of signal energy reflected at the bending point. Signal propagation attenuation and phase change along the cable length refer to the phenomenon where the amplitude of a signal gradually decreases and its phase continuously changes as it propagates from a specific point on the cable (e.g., the location of a bend) to the input end. This change is determined by factors such as the cable's dielectric loss, conductor loss, and dielectric constant, and is jointly determined by the cable's complex propagation constant and the actual distance the signal travels. Attenuation leads to signal energy loss, while phase change affects the signal's arrival time and waveform. The comprehensive dynamic reflection coefficient refers to the overall reflection characteristics obtained at the input end of a high-frequency cable after comprehensively considering the reflection effects caused by all dynamic factors (such as mechanical bending, temperature changes, etc.). It is not merely a local reflection generated at a single discontinuity point, but rather the equivalent result of local reflections (e.g., reflections generated at a bend) after attenuation and phase shifting by the cable transmission line, presented at the cable input end. This coefficient comprehensively reflects the dynamic electrical performance of the cable under actual operating conditions.

[0109] The solution in this application combines the impedance mismatch effect caused by local bending with the signal attenuation and phase shift characteristics during cable transmission to calculate the comprehensive dynamic reflection coefficient at the cable input end. Specifically, firstly, the dynamic bending impedance obtained by the aforementioned bending deformation reflection coefficient calculation module is used... The cable dynamic characteristic impedance output by the aforementioned temperature drift correction module The local reflection coefficient of the signal at the cable bend interface is calculated. This local reflection coefficient characterizes the signal reflection intensity caused by impedance discontinuity at the bend point. Secondly, considering the transmission line termination attenuation and phase shift characteristics experienced by the signal propagating from the bend point back to the cable input, this scheme further introduces an exponential attenuation term. .

[0110] Among them, the complex propagation constant output by the temperature drift correction module mentioned above This describes the attenuation and phase change of the signal as it propagates through the cable, while the total cable length L determines the distance the signal travels. The factor "2" in the exponent term represents the round-trip path of the signal from the input to the bend and back to the input.

[0111] In this way, the proposed scheme "maps" the local bending effect to the cable input and takes into account signal loss and phase accumulation along the transmission path, thus providing a comprehensive and accurate integrated dynamic reflection coefficient. This calculation method effectively solves the error caused by considering only local effects while ignoring the overall transmission line influence, making the evaluation of the electrical performance of high-frequency cables under complex dynamic conditions more accurate.

[0112] In a preferred embodiment of the present invention, in the error de-embedding module, the true input reflection coefficient and the true transmitted scattering coefficient are extracted from the original scattering parameter matrix through the following signal flow graph operation:

[0113]

[0114]

[0115] In the above formula, This represents the true input reflection coefficient after de-embedding and reconstruction; This represents the reconstructed true transmission scattering coefficient; , as well as These represent the original input reflection coefficient, original forward transmission coefficient, and original output reflection coefficient measured by the testing instrument, respectively.

[0116] In this embodiment, the error de-embedding module aims to extract parasitic errors related to the test environment and connectors from the raw data measured by the test instrument, thereby obtaining the true electrical characteristics of the high-frequency cable under test. Its function is to eliminate responses in the measurement path that are not related to the component under test itself through mathematical models and algorithms, thereby improving the accuracy and reliability of the measurement. This module can be implemented by a dedicated digital signal processor (DSP) for high-speed data processing and complex algorithm execution; or it can be implemented by a general-purpose computer in conjunction with professional measurement software, providing flexible algorithm configuration and data visualization capabilities.

[0117] True input reflection coefficient This represents the true reflection characteristics at the input end of the high-frequency cable after error de-embedding processing. It reflects the signal reflection caused by impedance mismatch at the cable input port, and has eliminated interference from external factors such as test fixtures and connectors. This coefficient is a key indicator for evaluating the matching performance of the cable input end and can be used to analyze the impedance uniformity or defects of the cable.

[0118] True transmission scattering coefficient This represents the true transmission characteristics of a high-frequency cable after error de-embedding processing. It reflects the attenuation and phase change of the signal from the cable input to the output, and has eliminated interference from external factors such as test fixtures and connectors. This coefficient is a key indicator for evaluating cable transmission loss, insertion loss, and phase response performance, and can be used to analyze the signal integrity of the cable. Signal flow graph decoupling and de-embedding is a mathematical processing method based on signal flow graph theory, used to separate the scattering parameters of a specific device under test from measurement data containing multiple reflections and transmission paths. Its function is to deduce the true response of the device under test by establishing a signal transmission model between the test system and the device under test, using known calibration data (such as the aforementioned comprehensive dynamic reflection coefficient). This operation can be implemented using matrix inversion algorithms to transform complex signal transmission relationships into a system of linear equations for solution; or it can be implemented using iterative optimization algorithms to gradually approximate the true scattering parameters.

[0119] The raw scattering parameter matrix contains the raw S-parameters directly measured by the testing instrument, including the raw input reflectance coefficient. Original forward transmission coefficient and original output reflection coefficient These parameters encompass the characteristics of the high-frequency cable under test, as well as parasitic effects introduced by environmental factors such as test fixtures, connectors, temperature, and bending. They serve as the raw data input for error de-embedding calculations.

[0120] Overall dynamic reflection coefficient The reflection coefficient calculated by the aforementioned bending deformation reflection module characterizes the input-end reflection properties of the high-frequency cable under specific temperature and bending deformation conditions, encompassing the combined effects of various parasitic factors such as mechanical bending, temperature drift, and connector interface contact impedance. In the error de-embedding operation, this coefficient serves as a known calibration term, used to extract these parasitic effects from the raw measurement data.

[0121] The solution in this application receives the raw scattering parameter matrix measured by the test instrument through an error de-embedding module. This matrix contains the comprehensive response of the high-frequency cable under actual test conditions, which is mixed with parasitic errors introduced by factors such as connector interface, temperature changes, and mechanical bending. To remove these parasitic errors, the error de-embedding module utilizes the comprehensive dynamic reflection coefficient provided by the bending deformation reflection coefficient calculation module. The integrated dynamic reflection coefficient precisely quantifies the reflection characteristics caused by the combined mechanical, thermal, and electromagnetic effects under specific test conditions. The error de-embedding module, based on signal flow graph theory, treats the entire test link as a system composed of multiple interconnected networks. By performing signal flow graph decoupling and de-embedding operations on the original scattering parameter matrix and the pre-calculated integrated dynamic reflection coefficient, this module effectively separates parasitic effects in the test system from the true response of the high-frequency cable under test. Specifically, this operation establishes a mathematical model describing the signal transmission path between the test port, connector, cable, and test instrument, and then uses the known integrated dynamic reflection coefficient as a calibration term to deduce the true input reflection coefficient belonging only to the high-frequency cable itself. and true transmission scattering coefficient This method ensures that the final S-parameters accurately reflect the inherent electrical performance of the high-frequency cable without being affected by external test conditions and connector characteristics.

[0122] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-frequency cable testing platform, characterized in that, include: The interface contact impedance characterization module is used to obtain the tightening torque, surface roughness and conductor material conductivity of the connector interface, calculate the dynamic contact resistance based on the coupling mechanism of contact mechanics and electromagnetic skin effect, and output the cascaded discontinuity impedance at the connector interface according to the dynamic contact resistance and the nominal characteristic impedance of the test platform interface. The temperature drift correction module, connected to the interface contact impedance characterization module, is used to collect the real-time temperature of the test environment and obtain the reference relative permittivity, reference dielectric loss tangent, volume thermal expansion coefficient, and temperature response sensitivity coefficient of dielectric loss of the insulating medium. It reconstructs the complex relative permittivity under temperature dispersion and, combined with the reference characteristic impedance constant of the cable and the complex relative permittivity, outputs the temperature-corrected dynamic characteristic impedance and complex propagation constant of the cable. The bending deformation reflection coefficient calculation module, connected to the temperature drift correction module, is used to obtain the outer diameter, measured bending radius and total length of the high-frequency cable, calculate the dynamic bending impedance based on the coaxial geometric eccentricity effect caused by bending deformation, and output the comprehensive dynamic reflection coefficient of the cable input end based on the dynamic bending impedance, the dynamic characteristic impedance, the complex propagation constant and the total length of the cable. The error de-embedding module, connected to the bending deformation reflection coefficient calculation module, is used to receive the original scattering parameter matrix measured by the test instrument, perform signal flow graph decoupling and de-embedding operations on the original scattering parameter matrix according to the comprehensive dynamic reflection coefficient, and output the true input reflection coefficient and the true transmission scattering coefficient after removing the comprehensive parasitic errors of mechanical, thermal and electromagnetic components.

2. The high-frequency cable testing platform according to claim 1, characterized in that, In the interface contact impedance characterization module, the dynamic contact resistance is calculated based on the following physical relationship: Based on the skin effect, where the actual conductive cross-sectional area of ​​the contact interface decreases with increasing frequency, and combined with the plastic deformation behavior of the contact spot under applied tightening torque, the specific calculation steps for the dynamic contact resistance are as follows: Divide 2 by the product of the test signal angular frequency, vacuum permeability and the conductor material reference conductivity, and then take the square root of the quotient to obtain the skin depth value; divide the microscopic average roughness of the contact surface by the skin depth value to obtain the first ratio, and then calculate 1 plus the square of the first ratio to obtain the skin effect correction factor. The square root of the skin effect correction factor is taken, and then the square root is multiplied by the reference conductivity of the conductor material to obtain the equivalent conductivity correction term. The tightening torque is divided by the product of the dimensionless torque coefficient of the thread, the nominal diameter of the connector thread, and the Vickers hardness of the contact material, and the square root of the quotient is taken to obtain the contact spot plastic deformation term. The contact spot plastic deformation term is divided by the equivalent conductivity correction term, and the quotient is used as the dynamic contact resistance.

3. The high-frequency cable testing platform according to claim 2, characterized in that, The cascaded discontinuous impedance is the sum of the dynamic contact resistance and the nominal characteristic impedance.

4. The high-frequency cable testing platform according to claim 3, characterized in that, In the temperature drift correction module, the complex relative permittivity is reconstructed based on the physical mechanisms of changes in molecular density caused by temperature variations in the volume of the insulating medium and changes in the polarization relaxation intensity of the medium with temperature variations. The specific calculation steps are as follows: The temperature change is obtained by subtracting the reference temperature from the measured ambient temperature; the real part correction factor is obtained by subtracting the product of the volume thermal expansion coefficient and the temperature change; the real part correction factor is obtained by multiplying the reference relative permittivity by the real part correction factor. The imaginary part correction factor is obtained by multiplying the temperature response sensitivity coefficient (which includes the dielectric loss) by the temperature change. The imaginary part coefficient of the complex relative permittivity is obtained by multiplying the tangent of the reference dielectric loss angle by the imaginary part correction factor. By combining the real and imaginary parts, with the coefficient before the imaginary unit being negative, the complex relative permittivity under temperature coupling is obtained.

5. The high-frequency cable testing platform according to claim 4, characterized in that, The cable dynamic characteristic impedance and the complex propagation constant are calculated based on the cable reference characteristic impedance constant and the complex relative permittivity: The dynamic characteristic impedance of the cable is obtained by correcting the reference characteristic impedance constant, which is determined by the physical geometry of the cable, for dielectric temperature dispersion. The specific calculation steps are as follows: The first step is to calculate the difference between the measured ambient temperature and the reference temperature; the second step is to calculate the product of the volume thermal expansion coefficient and this difference. The third step is to calculate the result of subtracting the product from the product and use it as a temperature correction factor. The fourth step is to calculate the product of the reference relative permittivity and the temperature correction factor, and then take the square root of the product. The fifth step is to divide the reference characteristic impedance constant by its square root, and the resulting quotient is used as the dynamic characteristic impedance of the cable after temperature change correction. The complex propagation constant is calculated based on the complex relative permittivity and the speed of light in vacuum. Specifically, the quotient obtained by dividing the angular frequency of the test signal by the speed of light in vacuum is multiplied by the square root of the complex relative permittivity, and the product is then multiplied by the imaginary unit.

6. The high-frequency cable testing platform according to claim 5, characterized in that, In the bending deformation reflection coefficient calculation module, the dynamic bending impedance is calculated based on the physical mechanism that the inner and outer conductors of the coaxial cable become geometrically eccentric during bending, causing the local characteristic impedance to deviate from the original characteristic impedance. Specifically: The difference between multiplying the temperature-corrected dynamic characteristic impedance of the cable by one and subtracting the following ratio is calculated: the numerator of this ratio is the square of the high-frequency cable outer diameter divided by eight times the measured bending radius, and the denominator is twice the square of the high-frequency cable outer diameter.

7. The high-frequency cable testing platform according to claim 6, characterized in that, The comprehensive dynamic reflection coefficient is based on the attenuation and phase shift characteristics of the transmission line termination, and is determined by the degree of mismatch between the dynamic bending impedance and the dynamic characteristic impedance at the bending interface, as well as the signal propagation attenuation and phase change along the cable length direction. Specifically: First, calculate the reflection coefficient at the curved interface. Specifically, use the difference between the dynamic bending impedance and the dynamic characteristic impedance as the numerator, and the sum of the dynamic bending impedance and the dynamic characteristic impedance as the denominator. Divide the numerator by the denominator to obtain the interface reflection coefficient. Next, calculate the propagation attenuation and phase change terms. Specifically, take the product of the complex propagation constant and twice the total cable length as an exponential function with the natural constant as the base. The value of this exponential function is a negative power. Finally, the interface reflection coefficient is multiplied by the propagation attenuation and phase change terms to obtain the comprehensive dynamic reflection coefficient.

8. The high-frequency cable testing platform according to claim 7, characterized in that, In the error de-embedding module, the true input reflection coefficient and the true transmitted scattering coefficient are extracted from the original scattering parameter matrix through the following signal flow graph operation: The calculation method for the true input reflection coefficient is as follows: the difference between the original input reflection coefficient measured by the testing instrument and the comprehensive dynamic reflection coefficient is used as the numerator, and the product of the original output reflection coefficient and the comprehensive dynamic reflection coefficient is subtracted from the numerator as the denominator. The quotient obtained by dividing the numerator by the denominator is used as the true input reflection coefficient after de-embedding and reconstruction. The true transmission scattering coefficient is calculated as follows: First, subtract the square of the comprehensive dynamic reflection coefficient from 1 to obtain the first factor. Then, subtract the product of the original output reflection coefficient and the comprehensive dynamic reflection coefficient from 1 to obtain the second factor. Divide the first factor by the second factor, and multiply the quotient by the original forward transmission coefficient to obtain the reconstructed true transmission scattering coefficient.

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