A method for testing high-frequency inductive impedance compensation of an electromagnetic launching device

Abstract

The application relates to the technical field of impedance compensation testing, in particular to a high-frequency inductive impedance compensation testing method for an electromagnetic emission device, which comprises the following steps: performing a wide-frequency open-circuit scanning calibration on a combination of a probe and a test fixture, and constructing a continuous stray capacitance curve covering target frequency points; determining a critical frequency based on physical parameters of a wire section, and determining winding alternating-current resistance in sections; collecting measured values of complex admittance of the measured electromagnetic emission device, combining the continuous stray capacitance curve to calculate real admittance, combining the winding alternating-current resistance to reconstruct real impedance; calculating a compensation admittance increment based on the real impedance to connect a compensation element, and reextracting the real impedance after the compensation element is connected to calculate a residual impedance vector, extracting a virtual part deviation of the residual impedance vector to perform iterative adjustment until the virtual part deviation falls within a preset tolerance band. The application effectively suppresses systematic deviation of a high-frequency compensation amount through double physical disturbance separation.

Description

Technical Field

[0001] This application relates to the field of impedance compensation testing technology, and in particular to a high-frequency inductive impedance compensation testing method for electromagnetic launching devices. Background Technology

[0002] In fields such as wireless communication, industrial IoT, and near-field power transmission, the high-frequency operating characteristics of electromagnetic transmission devices directly determine the overall system performance. Therefore, high-frequency impedance testing and compensation of inductive components such as coils, windings, and transmission antenna matching networks are core aspects of factory calibration and on-site commissioning. As operating frequencies continue to extend into the megahertz and above bands, the proportion of inductive impedance in the overall impedance gradually surpasses that of purely resistive components. If accurate testing of inductive impedance is not possible, the consistency of equipment performance will be constrained.

[0003] Chinese patent application CN113899952A discloses an automated impedance testing system and method, including a host computer, an impedance tester, a compensation and calibration circuit, and a switch matrix. The switch matrix is ​​mounted on a long test cable, which is connected to the input terminal of the impedance tester. The output terminal of the impedance tester is connected to the host computer. The impedance tester is used to automatically test the impedance of selected channels. The compensation and calibration circuit is used to eliminate the impedance introduced by the long test cable and the switch matrix. The output terminal of the compensation and calibration circuit is connected to the input terminal of the host computer. The host computer is used to correct the data measured by the impedance tester using the data obtained from the compensation and calibration circuit, compare the corrected data with a preset impedance criterion, and save the data.

[0004] Current high-frequency inductive impedance compensation testing typically relies on vector network analyzers or impedance analyzers, along with a standard SOLT calibration procedure. This process corrects the impedance contribution of the probe itself at the calibration plane and performs a frequency scan of the inductive element under test to extract the impedance magnitude and phase angle at different frequency points, thereby calculating the required compensation. This procedure provides reliable results in the low- or mid-frequency range and has become a mature standard in the industry.

[0005] However, when the test frequency exceeds 1MHz, the combined effect of the two types of physical effects fundamentally undermines the reliability of the aforementioned test procedure. The stray capacitance level formed by the residual lead length of the test probe and fixture and the pad area is typically between several picofarads and tens of picofarads, forming a parallel resonant circuit with the inductive component under test. This resonant frequency often falls within the target test frequency band, causing the measured impedance phase angle to deflect towards the capacitive direction before the true self-resonant frequency arrives. The phase error accumulates continuously with increasing frequency, reaching a non-negligible level at high frequencies. Simultaneously, the skin effect of the conductor increases the effective AC resistance of the winding wire with increasing frequency, compressing the quality factor Q value and further skewing the reference reference of the measured phase angle. SOLT calibration only corrects the port reflection once at the calibration plane and cannot separate these two effects from the measured data in subsequent actual measurements. If this data containing systematic phase deviation is used as the compensation reference, the calculated compensation amount itself carries the error, and this error monotonically accumulates with increasing frequency, ultimately leading to a false pass of the compensation verification on a mismatched reference. Summary of the Invention

[0006] To address the technical problem of systematic offset of compensation amount and false pass of compensation verification caused by the superposition of dual physical disturbances in the high-frequency band in the existing SOLT calibration process, this application provides a high-frequency inductive impedance compensation test method for electromagnetic launch devices.

[0007] This application provides a high-frequency inductive impedance compensation test method for electromagnetic launching devices, employing the following technical solution: S1. Perform wideband open-circuit scanning calibration on the probe and test fixture assembly, extract the stray capacitance corresponding to each frequency point, and construct a continuous stray capacitance curve covering the target frequency point. S2. Determine the critical frequency based on the physical parameters of the conductor cross-section, and determine the AC resistance of the winding in segments according to the relationship between the critical frequency and the current frequency. S3. Collect the measured value of the complex admittance of the electromagnetic transmitting device under test, calculate the true admittance in combination with the continuous stray capacitance curve, extract the pure reactance part based on the true admittance, and reconstruct the true impedance in combination with the AC resistance of the winding. S4. Calculate the compensation admittance increment based on the actual impedance to connect the compensation element, and re-extract the actual impedance after connecting the compensation element to calculate the residual impedance vector. Extract the imaginary part deviation of the residual impedance vector and perform iterative adjustment until the imaginary part deviation falls within the preset tolerance band.

[0008] By performing a wideband open-circuit scan of the probe and fixture assembly before formal measurement, the frequency dependence characteristics of stray capacitance are solidified, eliminating the continuous biasing effect of the probe parallel capacitor on the measured phase angle in the high-frequency band, so that the measurement results no longer drift systematically with batch differences in fixture condition.

[0009] Preferably, the process of performing wideband open-circuit scanning calibration on the probe and test fixture assembly, extracting stray capacitance corresponding to each frequency point, and constructing a continuous stray capacitance curve covering the target frequency point includes: suspending the probe and acquiring the real and imaginary parts of the admittance at each frequency point within the target frequency range; extracting the stray capacitance corresponding to each frequency point point by dividing the imaginary part of the admittance by twice the product of the current scanning frequency and pi; performing spline interpolation on the stray capacitance corresponding to each frequency point to finally obtain the continuous stray capacitance curve covering the target frequency point.

[0010] By constructing a continuous stray capacitance curve through wideband open-circuit scanning and spline interpolation, the frequency-dependent parasitic characteristics of the probe and fixture assembly are solidified, providing a high-frequency phase angle restoration numerical input for subsequent correction calculations and cutting off the path of fixture batch differences to the measurement results.

[0011] Preferably, the step of determining the critical frequency based on the physical parameters of the conductor cross-section, and determining the winding AC resistance in segments according to the relationship between the critical frequency and the current frequency, includes: obtaining the conductor radius, conductor resistivity, and permeability, and calculating the critical frequency based on the conductor radius, conductor resistivity, and permeability; when the current frequency is not greater than the critical frequency, using the winding DC resistance as the winding AC resistance; when the current frequency is greater than the critical frequency, correcting the DC resistance based on the ratio of the current frequency to the critical frequency, and finally obtaining the winding AC resistance.

[0012] By introducing a critical frequency determined by the physical parameters of the conductor cross-section and processing the frequency evolution of the winding AC resistance in segments according to frequency band, the true variation law of the winding resistive component is reconstructed in the entire frequency band, providing a correction benchmark for subsequent elimination of resistive error terms mixed in the calibration residuals.

[0013] Preferably, the step of acquiring the measured complex admittance of the electromagnetic transmitting device under test and calculating the true admittance in conjunction with the continuous stray capacitance curve includes: connecting the electromagnetic transmitting device under test to the test fixture and acquiring the measured complex admittance values ​​corresponding to each frequency point; calculating the product of the current angular frequency and the corresponding stray capacitance in the continuous stray capacitance curve to obtain the capacitive admittance contribution; and subtracting the measured complex admittance value from the capacitive admittance contribution to finally obtain the true admittance.

[0014] Preferably, the step of extracting the pure reactance portion based on the true admittance and reconstructing the true impedance by combining it with the winding AC resistance includes: taking the reciprocal of the true admittance to obtain a complex impedance after excluding interference from the probe parallel capacitor; extracting the imaginary part of the complex impedance as the pure reactance portion; combining the winding AC resistance as the real part and the pure reactance portion as the imaginary part to finally obtain the true impedance.

[0015] By performing a two-step operation of parallel admittance subtraction and explicit substitution of resistive components, the resistive drift caused by probe stray capacitance effect and skin effect is independently separated from the measured data, the true impedance of the measured inductive element is reconstructed, and the error propagation path driven by measured data containing systematic bias is cut off.

[0016] Preferably, the step of calculating the compensation admittance increment based on the actual impedance to connect the compensation element includes: obtaining the target matching impedance and calculating the reciprocal of the target matching impedance to obtain the target admittance; calculating the difference between the target admittance and the actual admittance to obtain the compensation admittance increment; determining the parameter values ​​of the compensation element according to the compensation admittance increment, and connecting the corresponding compensation element.

[0017] By basing the calculation of the compensation amount on a real, double-corrected admittance reference, a precise open-loop design for high-frequency inductive impedance compensation is achieved, and an optimal initial value is provided for closed-loop iterative adjustment, effectively suppressing the accumulation of compensation errors in the high-frequency band.

[0018] Preferably, the step of re-extracting the true impedance after connecting the compensation element to calculate the residual impedance vector, and extracting the imaginary deviation of the residual impedance vector for iterative adjustment, includes: re-executing the correction process combining the continuous stray capacitance curve and the winding AC resistance to extract the true impedance after connecting the compensation element; calculating the difference between the true impedance after connecting the compensation element and the target matching impedance to obtain the residual impedance vector; extracting the imaginary deviation of the residual impedance vector, and when the imaginary deviation exceeds the preset tolerance band, adjusting the compensation admittance increment for iterative adjustment.

[0019] Preferably, the step of waiting until the imaginary deviation falls within a preset tolerance band includes: obtaining the standing wave ratio (SWR) index of the device under test and deriving the port reflection coefficient based on the SWR index; calculating the allowable impedance deviation range of the port based on the port reflection coefficient and the system characteristic impedance; and calculating the ratio of the imaginary component of the impedance deviation range to the rated reactance amplitude to finally obtain the preset tolerance band.

[0020] Preferably, the step of combining the AC resistance of the winding as the real part and the pure reactance as the imaginary part to obtain the true impedance further includes: performing a rationality check on the real and imaginary parts of the true impedance respectively; determining whether the real part of the true impedance monotonically does not decrease with frequency, and whether the imaginary part of the true impedance monotonically increases with frequency below the self-resonant frequency; if there is an anomaly, backtracking to check the stray capacitance interpolation accuracy and DC resistance measurement value at the corresponding frequency point; the true impedance confirmed to be without anomalies after the rationality check is used as the input benchmark for subsequent compensation admittance increment calculation.

[0021] Before compensation calculation, a physical rationality defense is set up. Through two simple and clearly physically meaningful criteria, namely the monotonicity of the real part and the increasing nature of the imaginary part, as well as the corresponding anomaly backtracking guidance, it is ensured that the real impedance of the input compensation stage is reliable and without anomalies, thereby improving the accuracy of high-frequency inductive impedance compensation testing.

[0022] Preferably, the step of performing spline interpolation on the stray capacitance corresponding to each frequency point to finally obtain the continuous stray capacitance curve covering the target frequency point further includes: storing the continuous stray capacitance curve as an input parameter for subsequent correction calculations in the test record; obtaining the fixture model, probe specifications, and ambient temperature at the time of acquisition; and archiving and saving the continuous stray capacitance curve together with the fixture model, probe specifications, and ambient temperature.

[0023] This application has the following technical effects: By introducing a critical frequency determined based on the physical parameters of the conductor cross-section and employing a method that processes the frequency evolution of the winding AC resistance separately for each frequency band, resistive component correction values ​​are provided across the entire frequency band, avoiding the problem of confusing and superimposing resistive drift caused by the skin effect with measurement channel errors. In the residual verification stage, the upper and lower boundaries of the tolerance band are derived from the VSWR index of the device under test using existing reflection coefficient relationships, ensuring the physical consistency between the verification judgment criteria and the actual operating conditions of the device. The above processing ensures that the calculation and verification of the compensation amount are based on accurate physical references, effectively suppressing the systematic offset of the compensation amount caused by the superposition of dual physical disturbances in the high-frequency band, and improving the impedance matching consistency and repeatability of the electromagnetic launch device under wide-band operating conditions. Attached Figure Description

[0024] Figure 1 This is a flowchart of a high-frequency inductive impedance compensation test method for an electromagnetic launching device according to this application.

[0025] Figure 2 This is a schematic diagram comparing the frequency characteristics of the imaginary part of the winding impedance of this application with those of existing methods.

[0026] Figure 3This is a schematic diagram comparing the real part frequency characteristics of the winding impedance of this application with those of existing methods. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] This application discloses a high-frequency inductive impedance compensation test method for an electromagnetic launching device, referring to... Figure 1 This includes the following steps: S1. Wideband open-circuit scanning is used to construct continuous stray capacitance curves.

[0029] Before starting the formal test, a wideband open-circuit scan calibration is performed on the probe and test fixture assembly. With the probe suspended and not connected to any device under test, the real and imaginary parts of the admittance are sequentially acquired at uniform logarithmic intervals within the target frequency range. Since the probe impedance should tend to infinity under ideal open-circuit conditions, and the imaginary part of the measured admittance is not zero, its non-zero value is precisely the stray capacitance formed by the residual probe lead length and the pad area. The capacitive contribution generated at this frequency point. Due to the lead distribution effect, The stray capacitance is not strictly constant across the entire frequency band; it is extracted point by point using the following formula:

[0030] in, The stray capacitance of the probe and test fixture assembly at frequency f. The complex admittance measured in the open-circuit state. To take the imaginary part of a complex number, This is the current scanning frequency. The larger the value, the larger the residual length of the probe lead or the larger the pad area. The lower the parallel resonant frequency formed with the inductive component under test, the higher the risk of the resonant point falling into the target test frequency band, and the lower the measured phase angle deflection starting frequency. The smaller the value, the lower the aforementioned risk.

[0031] Furthermore, after completing the wideband scan, for each frequency point... Spline interpolation is performed on the dataset to construct a continuous stray capacitance curve covering all target frequency points. Since changes in the fixture geometry directly affect the equivalent length of the residual leads, this alters... The amplitude and frequency slope are calculated, therefore this curve is permanently saved with the current test task. Open-circuit calibration is not repeated without changing the fixture model or probe specifications. It should be noted that open-circuit calibration must be performed under the exact same fixture conditions as when the device under test was installed, and the probe clamping force and contact area must be consistent with the actual test to eliminate the impact of contact geometry changes. Interference with identification results. For batch testing scenarios, after the first piece in the same batch is calibrated, the calibration result can be directly reused for subsequent pieces. The curve effectively reduces the calibration cycle of a single piece while ensuring consistency within the batch.

[0032] Next, the interpolation will be completed. The curve is stored in the test record as an input parameter for subsequent correction calculations, along with the fixture model, probe specifications, and ambient temperature at the time of acquisition, for traceability of consistency in subsequent batches.

[0033] In this way, by constructing a continuous stray capacitance curve through wideband open-circuit scanning and spline interpolation, the frequency-dependent parasitic characteristics of the probe and fixture assembly are solidified, providing a high-frequency phase angle restoration numerical input for subsequent correction calculations. This cuts off the path of fixture batch differences to the measurement results and avoids operational consistency deviations introduced by repeated calibration of each piece.

[0034] S2. Determine the AC resistance of the winding based on the critical frequency segmentation.

[0035] DC resistance of inductive element winding Measurements were taken using a four-wire micro-ohmmeter under power frequency or DC conditions. As the current concentrates towards the surface of the conductor at higher frequencies, the effective conductive cross-section increases with the skin depth. The contraction reduces the size, of which For conductor resistivity, Permeability, The current scanning frequency. To determine the frequency boundary at which the skin effect begins to significantly affect the winding resistive components, a critical frequency is introduced. ,in Where is the radius of the conductor. For common copper circular cross-section windings, and All are inherent parameters. Determined by the physical dimensions of the conductor.

[0036] In an optional embodiment, the winding AC resistance Determined across the entire frequency band according to the following segmentation relationship: When At this time, the skin depth is not less than the conductor radius, and the current distribution within the conductor cross-section remains approximately uniform. ;when When the skin depth is less than the conductor radius, the effective conductive cross-section shrinks as the frequency increases, and the expression for the AC resistance of the winding is:

[0037] in, The AC resistance of the winding at frequency f is... The DC resistance of the inductive element winding, The critical frequency, This is the current scanning frequency.

[0038] because and All are positive values, and When the ratio is greater than 1, It increases monotonically with frequency. A larger value indicates a higher multiple of the current frequency relative to the critical frequency, a more severe shrinkage of the effective cross-section, and a lower quality factor. The greater the compression of the value, the smaller the value indicates that the current frequency is still in the early stages of the skin effect, and the resistive component deviates from the DC value by a limited margin. Compared to the step-like abrupt change at the threshold of hard gating, the above piecewise relationship... The natural continuity provides a gradual transition, avoiding the oscillation problem of repeated jumps near the threshold due to small fluctuations.

[0039] It should be noted that the reference load used for SOLT calibration is a pure resistance standard of 50Ω, which does not contain a frequency-dependent skin effect term. Therefore, the calibrated measurement channel will still use the winding itself. Frequency drift was mistakenly attributed to external environmental interference and retained in the measurement results. Since this source of error cannot be eliminated through port calibration, it was explicitly replaced with physically derived values ​​during data post-processing to restore the true frequency evolution of the winding resistive components. Extraction Then, the true values ​​of the resistive components of the complex impedance of the winding were obtained at each frequency point, providing input for the resistive substitution step in the subsequent correction.

[0040] Thus, by introducing a critical frequency determined by the physical parameters of the conductor cross-section and processing the frequency evolution of the winding AC resistance in segments according to frequency band, the true variation law of the winding resistive component is reconstructed in the entire frequency band, providing a correction benchmark for subsequent elimination of resistive error terms mixed in the calibration residuals.

[0041] S3. Reconstruct the true impedance by combining stray capacitance and AC resistance.

[0042] In one optional embodiment, after the electromagnetic transmitting device under test is formally connected to the test fixture, the measured values ​​of complex admittance are collected at each frequency point. Due to probe stray capacitance The true admittance of the inductive element under test is obtained by connecting the two ends of the inductive element in parallel. The following relationship exists between the measured admittance and the actual admittance:

[0043] in, For the inductive element under test at frequency The actual admittance below, For frequency Measured value of complex admittance under the given condition. The stray capacitance of the probe and test fixture assembly at frequency f. It is the imaginary unit.

[0044] The product of the current angular frequency and the corresponding stray capacitance in the continuous stray capacitance curve constitutes the capacitive admittance contribution. The larger the value, the greater the contribution of the parallel capacitive branch to the imaginary part of the measured admittance, and the more severe the measured phase angle deflection towards capacitiveness. The smaller the value, the less pronounced the deflection. Taking the reciprocal yields the complex impedance after removing the influence of the probe. Its imaginary part This is already a purely inductive reactance after eliminating interference from probe parallel capacitors; however, it still contains reactance that SOLT calibration cannot automatically separate. contribute.

[0045] Furthermore, after SOLT calibration has corrected the reflection at the measurement channel port to the nominal value, The magnitude of the residual resistive term in the instrument channel in the real part is much smaller than that in the instrument channel. The amount of drift with frequency, derived from physics. replace The approximation condition for the real part has been satisfied. Therefore, the pure reactance of the inductive component is extracted, and the true impedance is reconstructed:

[0046]

[0047] in, For the inductive element under test at frequency The pure sense of resistance, To take the imaginary part of a complex number, To eliminate the influence of the probe on the complex impedance at frequency f, This represents the reconstructed true impedance at frequency f. The AC resistance of the winding at frequency f is... It is the imaginary unit.

[0048] Next, regarding The real and imaginary parts are checked for rationality separately: the real part should monotonically increase with frequency, and the imaginary part should monotonically increase with frequency below the self-resonant frequency; for any abnormal trend at any frequency point, a backtracking check of that point is used. Interpolation accuracy and The measurement method is used to ensure data accuracy. The data has been verified to be normal and without abnormalities. This serves as the input benchmark for subsequent compensation admittance increment calculations. The two-step operation of subtracting the parallel admittance and explicitly replacing the resistive component together completes the separation and correction of two independent physical effects: the first step eliminates the phase angle deflection introduced by the probe's parallel capacitance, and the second step replaces the resistive error term mixed in with the calibration residual with the physically derived AC resistance. After this dual correction... This is the true impedance of the inductive element under test at each frequency point, which can be directly used as the reference for calculating the compensation amount.

[0049] Thus, through a two-step operation of subtracting the parallel admittance and explicitly replacing the resistive component, the resistive drift caused by the stray capacitance effect of the probe and the skin effect is independently separated from the measured data, the true complex impedance of the measured inductive element is reconstructed, and the error propagation path driven by the measured data containing systematic bias is cut off.

[0050] S4. Calculate the residual impedance vector and iteratively adjust it to the tolerance zone.

[0051] by Based on the target matching impedance The target admittance is obtained by calculating the reciprocal of the target matching impedance, and then the required compensation admittance increment at each frequency point is calculated. This process determines the parameter values ​​for the compensation element. After the compensation element is connected, the established correction process combining the continuous stray capacitance curve and the winding AC resistance is repeated to re-extract the true impedance of the entire network after compensation. .

[0052] In an optional embodiment, With target impedance The deviation is defined as the residual impedance vector. The real part of the offset (resistive residual) and the imaginary part of the offset (inductive residual) are extracted and tracked independently. Since the impedance matching quality of inductive components is mainly controlled by the imaginary offset, and the resistive residual usually only affects insertion loss and does not directly cause reflection, the imaginary residual is used as the main criterion for iterative convergence: if the imaginary residual at any frequency point exceeds the preset tolerance band, it is determined that the compensation at that frequency point is insufficient. The system automatically locates that frequency point and iteratively adjusts the compensation amount until the entire frequency band is reached. The absolute values ​​of the imaginary parts all fall within the tolerance range.

[0053] Furthermore, the upper and lower limits of the tolerance band are determined by the actual operating bandwidth requirements of the device under test. Using the rated reactance component amplitude within the device's operating frequency band as a benchmark, the tolerance ratio is derived from the VSWR (Standing Wave Ratio) specification: VSWR is related to the port reflection coefficient. There are existing relationships:

[0054] Port impedance Let the target impedance be... The maximum allowable impedance deviation amplitude is then... Simplifying, we get:

[0055] The above derivation is in This holds true under normal matching conditions (i.e., VSWR greater than 1). For example, the system characteristic impedance. The value can be 50Ω. Dividing the imaginary part of the impedance deviation range by the rated reactance amplitude determines the upper and lower bounds of the tolerance ratio. It should be noted that other indicators that can characterize port matching quality include return loss, etc. Those skilled in the art can choose different derivation paths to determine the tolerance band according to actual needs, and are not limited to the VSWR derivation method in this embodiment. After the full-band residual verification is passed, a compensation parameter report with dual separation correction is output, and the values ​​at each frequency point are recorded. and The correction amount is used for consistency traceability in subsequent batch testing.

[0056] In this way, by associating the tolerance band with the VSWR index of the device under test, and by tracking the resistive and inductive residuals separately and driving iterative convergence with the inductive residual as the main criterion, the residual verification stage confirms the adequacy of compensation under the physical consistency judgment standard, ensuring that the final output compensation parameters meet the impedance matching accuracy requirements of the actual working conditions of the device in the entire frequency band.

[0057] The technical effects of this application can also be illustrated in conjunction with the accompanying drawings. Figure 2 The horizontal axis represents frequency (MHz), and the vertical axis represents the imaginary part of impedance (Ω). The dashed line represents the imaginary part curve of the existing method with stray capacitance offset, while the solid line represents the real reactance curve restored by the method of this application after double correction. The difference between the two is particularly significant in the high-frequency range. Figure 3 The horizontal axis represents frequency (MHz), and the vertical axis represents the real part of impedance (Ω). The dashed line represents the resistive component of the existing method with skin error, and the solid line represents the true resistive component of the method in this application after the segmented AC resistor is replaced. It can be observed that the resistive component of the method in this application converges more smoothly across the entire frequency band.

[0058] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for testing high-frequency inductive impedance compensation in an electromagnetic launching device, characterized in that, Including the following steps: S1. Perform wideband open-circuit scanning calibration on the probe and test fixture assembly, extract the stray capacitance corresponding to each frequency point, and construct a continuous stray capacitance curve covering the target frequency point. This includes: suspending the probe and collecting the real and imaginary parts of the admittance at each frequency point within the target frequency range; extracting the stray capacitance corresponding to each frequency point by dividing the imaginary part of the admittance by twice the product of the current scanning frequency and pi; and performing spline interpolation on the stray capacitance corresponding to each frequency point to obtain a continuous stray capacitance curve covering the target frequency point. S2. Determine the critical frequency based on the physical parameters of the conductor cross-section. Based on the relationship between the critical frequency and the current frequency, determine the AC resistance of the winding in segments, including: obtaining the conductor radius, conductor resistivity, and permeability; calculating the critical frequency based on the conductor radius, conductor resistivity, and permeability; when the current frequency is not greater than the critical frequency, use the DC resistance of the winding as the AC resistance of the winding; when the current frequency is greater than the critical frequency, correct the DC resistance based on the ratio of the current frequency to the critical frequency to obtain the AC resistance of the winding. S3. Collect the measured complex admittance values ​​of the electromagnetic transmitting device under test, and calculate the true admittance by combining the continuous stray capacitance curve. This includes: connecting the electromagnetic transmitting device under test to the test fixture, collecting the measured complex admittance values ​​corresponding to each frequency point; calculating the product of the current angular frequency and the corresponding stray capacitance in the continuous stray capacitance curve to obtain the capacitive admittance contribution; and subtracting the measured complex admittance value from the capacitive admittance contribution to obtain the true admittance. The process involves extracting the pure reactance based on the true admittance and reconstructing the true impedance by combining it with the winding AC resistance. This includes: taking the reciprocal of the true admittance to obtain the complex impedance after excluding interference from the probe parallel capacitor; extracting the imaginary part of the complex impedance as the pure reactance; and combining the winding AC resistance as the real part and the pure reactance as the imaginary part to obtain the true impedance. S4. Calculate the compensation admittance increment based on the actual impedance to connect the compensation element. Re-extract the actual impedance after connecting the compensation element to calculate the residual impedance vector. Extract the imaginary part deviation of the residual impedance vector and perform iterative adjustment until the imaginary part deviation falls within the preset tolerance band.

2. The high-frequency inductive impedance compensation test method for an electromagnetic launching device according to claim 1, characterized in that, The step of calculating the compensation admittance increment based on the actual impedance to connect the compensation element includes: obtaining the target matching impedance and calculating the reciprocal of the target matching impedance to obtain the target admittance; calculating the difference between the target admittance and the actual admittance to obtain the compensation admittance increment; determining the parameter values ​​of the compensation element according to the compensation admittance increment, and connecting the corresponding compensation element.

3. The high-frequency inductive impedance compensation test method for an electromagnetic launching device according to claim 1, characterized in that, The process of re-extracting the true impedance after connecting the compensation element, calculating the residual impedance vector, and iteratively adjusting the imaginary part deviation of the residual impedance vector includes: The correction process combining the continuous stray capacitance curve and the winding AC resistance is re-executed to extract the true impedance after connecting the compensation element; the difference between the calculated true impedance and the target matching impedance is used to obtain the residual impedance vector; the imaginary part deviation of the residual impedance vector is extracted, and when the imaginary part deviation exceeds the preset tolerance band, the compensation admittance increment is adjusted iteratively.

4. The high-frequency inductive impedance compensation test method for an electromagnetic launching device according to claim 1, characterized in that, The process of ensuring that the imaginary deviation falls within the preset tolerance band includes: Obtain the standing wave ratio (SWR) of the device under test, and derive the port reflection coefficient based on the SWR; calculate the allowable impedance deviation range of the port based on the port reflection coefficient and the system characteristic impedance; calculate the ratio of the imaginary part of the impedance deviation range to the rated reactance amplitude to obtain the preset tolerance band.

5. The high-frequency inductive impedance compensation test method for an electromagnetic launching device according to claim 1, characterized in that, After combining the winding AC resistance as the real part and the pure reactance as the imaginary part to obtain the true impedance, the method further includes: verifying the rationality of the real and imaginary parts of the true impedance separately; determining whether the real part of the true impedance monotonically does not decrease with frequency, and whether the imaginary part of the true impedance monotonically increases with frequency below the self-resonant frequency; if there is an abnormality, backtracking to check the stray capacitance interpolation accuracy and DC resistance measurement value at the corresponding frequency point. The actual impedance, which has been verified to be normal and without any abnormalities, is used as the input reference for subsequent calculation of the compensation admittance increment.

6. The high-frequency inductive impedance compensation test method for an electromagnetic transmitting device according to claim 1, characterized in that, After performing spline interpolation on the stray capacitance corresponding to each frequency point to obtain a continuous stray capacitance curve covering the target frequency point, the method further includes: storing the continuous stray capacitance curve as an input parameter for subsequent correction calculations in the test record; obtaining the fixture model, probe specifications, and ambient temperature at the time of acquisition; and archiving and saving the continuous stray capacitance curve together with the fixture model, probe specifications, and ambient temperature.

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