Method for constructing data-based s-parameter calibration fixture

Abstract

This invention provides a method for constructing a data-based S-parameter calibration component, comprising the following steps: setting calibration parameters of a vector network analyzer; using the vector network analyzer to calibrate an open-circuit standard, a short-circuit standard, and a load-matching standard based on LRM and MTRL algorithms; and, upon successful calibration, acquiring the data-based S-parameters of the open-circuit standard, the short-circuit standard, and the load-matching standard. This method for constructing a data-based S-parameter calibration component effectively improves the accuracy of the calibration algorithm while ensuring the convenience of the calibration operation.

Description

Technical Field

[0001] This invention relates to the technical field of calibration components, and in particular to a method for constructing a data-based S-parameter calibration component. Background Technology

[0002] The main difference between using a vector network analyzer for testing and using other instruments is that a calibration step is required before testing. In existing technologies, calibration typically requires the use of S-parameter calibrators. Therefore, the manufacturing precision and parameter quality of the S-parameter calibrators directly determine the accuracy of the calibration results. With the increasing use of S-parameter calibrators in applications such as 5G and 6G satellite-network communication, automotive radar, and security, the frequency of use of S-parameter calibrators is gradually rising to the millimeter-wave band, making it increasingly difficult to guarantee calibration accuracy based on data obtained through model fitting.

[0003] Currently, the most commonly used S-parameter calibration kits are SOLT (Short-Open-Load-Thru) / SOLR (Short-Open-Load-Reciprocal) calibration kits based on 0th to 3rd order polynomial model fitting data. Due to the limitations of their mathematical models, no matter how weighted fitting is performed, it is difficult to maintain model accuracy across the DC to 40GHz frequency range or even wider, especially in terms of the accuracy of parameter description for load matching standards. This results in poor calibration accuracy, and the residual error gradually increases with increasing frequency.

[0004] In addition, the LRM (Line-Reflect-Match) + MTRL (Multiline Thru Reflection Load) calibration kit has the following drawbacks:

[0005] (1) The operation is complicated and high-risk, and it is very easy to damage the calibration parts or cables;

[0006] (2) For coaxial applications above 50GHz, the physical size of the center conductor air wire structure is too small to be operated in a typical laboratory.

[0007] The aforementioned problems greatly limit the application scope of the LRM+MTRL calibration method in practical applications, and ultimately, due to the complexity of the operation, too many errors are introduced, which may prevent the achievement of the expected accuracy. Summary of the Invention

[0008] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for constructing a data-based S-parameter calibration component, which effectively improves the accuracy of the calibration algorithm and ensures the convenience of the calibration operation.

[0009] To achieve the above and other related objectives, the present invention provides a method for constructing a data-based S-parameter calibration component, comprising the following steps: setting calibration parameters of a vector network analyzer; using the vector network analyzer to calibrate an open-circuit standard, a short-circuit standard, and a load-matching standard based on LRM and MTRL algorithms; and, after the calibration is successful, acquiring the data-based S-parameters of the open-circuit standard, the short-circuit standard, and the load-matching standard.

[0010] In one embodiment of the present invention, the calibration parameters include power-on warm-up time, test start frequency, frequency step, intermediate frequency bandwidth, input power, source and receiver settings, and average number of tests.

[0011] In one embodiment of the present invention, the air wire structure of the open circuit standard, the short circuit standard and the load matching standard adopts a ballless structure.

[0012] In one embodiment of the present invention, the load matching standard is composed of a resistive element connected to a coaxial standard, and has a DC impedance of 50Ω.

[0013] In one embodiment of the present invention, an auxiliary testing tool is used to calibrate the open-circuit standard, the short-circuit standard, and the load-matching standard based on the LRM and MTRL algorithms. This tool is used to move and fix the open-circuit standard, the short-circuit standard, and the load-matching standard.

[0014] In one embodiment of the present invention, the auxiliary testing tool includes a support platform, a precision guide rail placed on the support platform, a sliding mechanism, a micrometer, a first limiting mechanism, and a second limiting mechanism; the first limiting mechanism is disposed at one end of the support platform; the micrometer is connected to the first limiting mechanism and is used to set the precise position of the first limiting mechanism; the precision guide rail is disposed on the support platform; the sliding mechanism is disposed on the precision guide rail; the second limiting mechanism is disposed on the precision guide rail to limit the range of motion of the sliding mechanism between the first limiting mechanism and the second limiting mechanism.

[0015] In one embodiment of the present invention, the following formula is used to calibrate the open-circuit standard, short-circuit standard, and load-matching standard based on the LRM and MTRL algorithms:

[0016]

[0017]

[0018]

[0019] E 01 E 10 =ΔE+E 00E 11 ;

[0020] Among them, E 00 Indicates the forward directional term, E 01 Indicates reverse error, E 10 Indicates positive error, E 11 Indicates the forward source match, Γ O ,Γ S ,Γ L Γ represents the reflection coefficients of the open-circuit standard, the short-circuit standard, and the load-matching standard, respectively. MO ,Γ MS ,Γ ML These represent the reflection coefficients of the open-circuit standard, the short-circuit standard, and the load-matching standard, respectively, when calibrated to the coaxial end face.

[0021] In one embodiment of the present invention, the data set S-parameter calibration component is further encapsulated.

[0022] As described above, the data-based S-parameter calibration method of the present invention has the following beneficial effects:

[0023] (1) The data base SOLT / SOLR calibration kit used combines the advantages of SOLT / SOLR calibration kit and LRM+MTRL calibration kit. Its accuracy is only slightly inferior to LRM+MTRL calibration kit, but its operation is no different from SOLT / SOLR calibration kit, making it the best choice to balance accuracy and ease of operation in actual coaxial calibration applications.

[0024] (2) It effectively improves the accuracy of the calibration algorithm and ensures the convenience of calibration operation. Attached Figure Description

[0025] Figure 1 The flowchart shown is an embodiment of the data base S-parameter calibration method of the present invention;

[0026] Figure 2 The diagram shown is a structural schematic of the coaxial load matching standard component of the present invention in one embodiment.

[0027] Figure 3 The diagram shown is a structural schematic of the on-chip load matching calibration component of the present invention in one embodiment.

[0028] Figure 4(a) shows a top view of an embodiment of the LRM+MTRL calibration auxiliary mechanism of the present invention;

[0029] Figure 4(b) shows a side view of the LRM+MTRL calibration auxiliary mechanism of the present invention in one embodiment;

[0030] Figure 4(c) shows a cross-sectional view of the LRM+MTRL calibration auxiliary mechanism of the present invention in one embodiment;

[0031] Figure 5 The diagram shown is a signal flow graph of a single-port calibration model of the present invention in one embodiment. Detailed Implementation

[0032] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0033] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0034] The data-based S-parameter calibration component construction method of the present invention improves the accuracy of the calibration algorithm and ensures the convenience of calibration operation by designing key manufacturing processes and special auxiliary tools, and correcting the core formula.

[0035] like Figure 1 As shown, in one embodiment, the data base S-parameter calibration component construction method of the present invention includes the following steps:

[0036] Step S1: Set the calibration parameters for the vector network analyzer.

[0037] The construction of the data-based S-parameter calibration component of this invention relies on a vector network analyzer. A vector network analyzer is a device for testing electromagnetic wave energy. It can measure the amplitude of various parameters of single-port or two-port networks, as well as the phase. The vector network analyzer can display the test data using a Smith chart.

[0038] Specifically, in an environment with precise temperature and humidity control (e.g., temperature variation ±0.5℃, relative humidity 40%–60%), a vector network analyzer in good working order and within its metrological validity period should be used, and all accessory cables should be metrological grade and in good condition. Before testing, the vector network analyzer should be powered on and warmed up for at least 30 minutes, and calibration parameters should be set, such as the test start frequency, frequency step (e.g., 10MHz or 100MHz), intermediate frequency bandwidth (e.g., 100Hz), input power (e.g., 0dBm), source and receiver settings (e.g., set to 0dB), and average number of tests (e.g., 10).

[0039] Step S2: Using the vector network analyzer, calibrate the open-circuit standard, short-circuit standard, and load-matching standard based on the LRM and MTRL algorithms.

[0040] Specifically, when constructing the data-based S-parameter calibration component, the key process control items are the load matching standard and the through standard. The structure of the coaxial load matching standard is as follows: Figure 2 As shown, the error of the load matching standard increases significantly with increasing frequency, leading to greater manufacturing difficulty. Preferably, the load matching standard of this invention consists of a resistive element connected to a coaxial standard, typically using a thin-film circuit coated with tantalum nitride (TaN), and requires precise resistance adjustment to ensure a DC impedance of 50Ω. The structure of the on-chip load matching calibration component is as follows... Figure 3 As shown. Preferably, a laser trimming machine is used in conjunction with a semiconductor parameter analyzer, a precision power supply, or a high-precision multimeter to employ a "four-wire method" with real-time feedback closed-loop control to precisely control the sheet resistance of the resistor layer to within 50Ω / sq. Process control requires that the DC resistance error be controlled within 0.1% after adjustment. Furthermore, for through-type standard parts, 3D electromagnetic field simulation is used to obtain the optimal dimensional parameters, which, combined with precise processing, ensures that the characteristic impedance of the transmission line is 50Ω.

[0041] In one embodiment of the present invention, the air wire structure of the open-circuit standard, the short-circuit standard, and the load matching standard adopts a beadless structure. The beadless air wire is the most precise component in microwave calibration and is ultimately traceable to the fundamental length dimension in metrology.

[0042] In one embodiment of the present invention, an auxiliary testing tool is used to calibrate the open-circuit standard, short-circuit standard, and load-matching standard based on LRM and MTRL algorithms. This tool is used to move and fix the open-circuit standard, the short-circuit standard, and the load-matching standard. Specifically, since the operation of the beadless air wire in coaxial LRM+MTRL calibration is difficult and risky, the present invention employs... Figures 4(a)-4(b)The specialized auxiliary testing tool shown can precisely control the XYZ stroke and is equipped with mechanical limit and locking protection mechanisms, greatly reducing the difficulty and risk of manual operation, while eliminating data jitter and noise caused by cable displacement during testing. Specifically, the auxiliary testing tool includes a support platform 1, a precision guide rail 2 placed on the support platform 1, a sliding mechanism 3, a micrometer 4, a first limiting mechanism 5, and a second limiting mechanism 6. The first limiting mechanism 5 is located at one end of the support platform 1. The micrometer 4 is connected to the first limiting mechanism 5 and is used to set the precise position of the first limiting mechanism 5. The precision guide rail 2 is located on the support platform 1, the sliding mechanism 3 is located on the precision guide rail 2, and the second limiting mechanism 6 is located on the precision guide rail 2 to limit the range of motion of the sliding mechanism 3 between the first limiting mechanism 5 and the second limiting mechanism 6. Preferably, the auxiliary testing tool also includes a locking protection mechanism 7 for locking the precision guide rail 2 on the support platform 1. More preferably, the first limiting mechanism 5 and the sliding mechanism 6 are set at the same height.

[0043] The signal flow graph of the single-port calibration model is as follows: Figure 5 As shown. According to the signal flow graph, the error equation satisfies and ΔE=E 01 E 10 -E 00 E 11 Among them, E 00 Indicates the forward directional term, E 01 Indicates reverse error, E 10 Indicates positive error, E 11 Indicates the forward source match, Γ O ,Γ S ,Γ L Γ represents the reflection coefficients of the open-circuit standard, the short-circuit standard, and the load-matching standard, respectively. MO ,Γ MS ,Γ ML These represent the reflection coefficients of the open-circuit standard, the short-circuit standard, and the load-matching standard, respectively, when calibrated to the coaxial end face. To simplify calculations, assume Γ... L =0, then we can get E 00 =Γ ML , and However, the above assumptions lead to deviations in accuracy for high-frequency data. To ensure accuracy, this invention uses the following formula to calibrate the open-circuit standard, short-circuit standard, and load-matching standard:

[0044]

[0045]

[0046]

[0047] E 01 E 10 =ΔE+E 00 E 11 .

[0048] Step S3: After the calibration is passed, obtain the data base S parameters of the open circuit standard, the short circuit standard, and the load matching standard.

[0049] Specifically, after LRM and MTRL calibrations are passed, the open-circuit standard, short-circuit standard, and load-matching standard are measured one by one, and the measured data-based S-parameters are stored in .s1p or .dat format. Since the air wire calibration component can be traced back to the length dimension, its length uncertainty data can ultimately be converted into the uncertainty data of the data-based calibration component for storage.

[0050] In one embodiment of the present invention, the method for constructing a data-based S-parameter calibration component further includes encapsulating the dataset S-parameter calibration component. Specifically, the data-based S-parameters are encapsulated using software that supports data-based S-parameter calibration components, the vector network analyzer's own software, or third-party calibration software to form a data-based S-parameter calibration component format that can be called by the software.

[0051] In summary, the data-based S-parameter calibration method of this invention utilizes a data-based SOLT / SOLR calibration component that combines the advantages of both the SOLT / SOLR and LRM+MTRL calibration components. While its accuracy is only slightly lower than the LRM+MTRL calibration component, its operation is identical to the SOLT / SOLR calibration component, making it the optimal choice for practical coaxial calibration applications that balances accuracy and ease of operation. This effectively improves the accuracy of the calibration algorithm while ensuring the convenience of calibration operations. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and possesses high industrial applicability.

[0052] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for constructing a data-based S-parameter calibration component, characterized in that, Includes the following steps: Set the calibration parameters for the vector network analyzer; The vector network analyzer is used to calibrate open-circuit, short-circuit, and load-matching standards based on LRM and MTRL algorithms. Once the calibration is successful, the data base S-parameters of the open-circuit standard, the short-circuit standard, and the load matching standard are obtained; The following formula is used to calibrate open-circuit, short-circuit, and load-matching standards based on LRM and MTRL algorithms: ； ； ； ； Among them, E 00 Indicates the forward directional term, E 01 Indicates reverse error, E 10 Indicates positive error, E 11 Indicates the forward source match, Γ O ,Γ S ,Γ L Γ represents the reflection coefficients of the open-circuit standard, the short-circuit standard, and the load-matching standard, respectively. MO ,Γ MS ,Γ ML These represent the reflection coefficients of the open-circuit standard, the short-circuit standard, and the load-matching standard, respectively, when calibrated to the coaxial end face.

2. The method for constructing a data-based S-parameter calibration component according to claim 1, characterized in that: The calibration parameters include power-on warm-up time, test start frequency, frequency step, intermediate frequency bandwidth, input power, source and receiver settings, and average number of tests.

3. The method for constructing a data-based S-parameter calibration component according to claim 1, characterized in that: The air wire structure of the open circuit standard component, the short circuit standard component, and the load matching standard component adopts a ball-free structure.

4. The method for constructing a data-based S-parameter calibration component according to claim 1, characterized in that: The load matching standard is composed of a resistive element connected to a coaxial standard, and has a DC resistance of 50Ω.

5. The method for constructing a data-based S-parameter calibration component according to claim 1, characterized in that: The calibration of open-circuit, short-circuit, and load-matching standards based on LRM and MTRL algorithms employs auxiliary testing tools for moving and fixing the open-circuit, short-circuit, and load-matching standards.

6. The method for constructing a data-based S-parameter calibration component according to claim 5, characterized in that: The auxiliary testing tool includes a support platform, a precision guide rail placed on the support platform, a sliding mechanism, a micrometer, a first limiting mechanism, and a second limiting mechanism; the first limiting mechanism is located at one end of the support platform; the micrometer is connected to the first limiting mechanism and is used to set the precise position of the first limiting mechanism; the precision guide rail is located on the support platform; the sliding mechanism is located on the precision guide rail; the second limiting mechanism is located on the precision guide rail to limit the range of motion of the sliding mechanism between the first limiting mechanism and the second limiting mechanism.

7. The method for constructing a data-based S-parameter calibration component according to claim 1, characterized in that: It also includes encapsulating the data base S-parameter calibration component.

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