A method for zero-point correction of S-parameter models, electronic devices and storage media

Abstract

A method for zero-point correction of an S-parameter model includes: calculating the S-parameters at zero frequency based on the constructed S-parameter model; calculating the error matrix between the S-parameter model and the original S-parameters at zero frequency; calculating the residues corresponding to the preset real poles based on preset real poles and the error matrix; and adding a term to the S-parameter model using the preset real poles and their corresponding residues to obtain the zero-point corrected S-parameter model. This method further corrects the S-parameters after vector fitting and passivity correction, ensuring that the values ​​of the S-parameters at zero frequency remain consistent with the original S-parameters while minimizing disruption of the original model's passivity and maintaining accuracy. This corrects the error of the original model's S-parameters at zero frequency, eliminating errors in subsequent simulations caused by the inaccuracy of the S-parameters at zero frequency.

Description

Technical Field

[0001] This invention relates to the field of S-parameter modeling technology for passive devices, and in particular to a method for zero-point correction of S-parameter models. Background Technology

[0002] S-parameters (Scattering parameters) are widely used in modeling passive devices. In practical applications, S-parameters are frequently measured and post-processed. S-parameters represent the signal relationships between ports in a circuit, such as reflection, loss, and crosstalk, and are used to simulate the behavior of electronic components at different frequencies. To introduce a complex passive device into circuit simulation, the S-parameters of this complex structure are usually extracted, and then the complex structure is considered as a black box with specific S-parameters in the circuit simulation. Before using S-parameters for circuit simulation, S-parameters need to be modeled. Then, the modeled S-parameters need to be converted into impulse responses or circuits of a certain scale for subsequent circuit simulation. The process involves first obtaining the original S-parameter data, performing S-parameter modeling, and then using the S-parameter model for circuit simulation.

[0003] Experimentally obtained S-parameters cannot usually be directly converted to impulse response because they are only given within a certain frequency range, while the time-domain impulse response requires S-parameters across the entire frequency range. To use S-parameters for circuit simulation, they need to be modeled, correcting any parts of the original S-parameters that do not conform to causality and passivity, and simultaneously expanding the frequency range of the original S-parameters. This is equivalent to extending the S-parameters in the frequency domain, which is crucial for obtaining correct results in subsequent circuit simulations.

[0004] A common approach to S-parameter modeling is to first perform vector fitting on the S-parameters, then apply passive correction, and finally convert the processed frequency-domain S-parameters into impulse response or circuit form. Since the S-parameters originate from experiments or device models, the modeled S-parameters should match the original S-parameter data as closely as possible within a given frequency range. Because the modeling process inevitably introduces errors, it is desirable to minimize these errors. Although the modeled S-parameters may have some errors compared to the original experimental data at various frequencies, as long as these errors are small, they generally will not adversely affect the system. However, the S-parameters at zero frequency determine the DC characteristics of the system and usually need to be precisely determined. Especially in some cases, the S-parameters are almost zero at zero frequency; errors here may adversely affect transient simulations. In the above modeling process, since error control is performed on the S-parameters at all frequencies, algorithms for individually controlling the error of S-parameters at a specific frequency are complex and computationally expensive. The method proposed in this patent ensures that the S-parameters and the original S-parameters have the same value at zero frequency while minimizing the loss of passivity of the original model and maintaining accuracy, thus providing a new option for S-parameter modeling. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for zero-point correction of S-parameter models. This method further corrects the S-parameters after vector fitting and passivity correction, ensuring that the values ​​of the S-parameter models at the zero-frequency point are consistent with the original S-parameters, while maximizing the accuracy and passivity of the zero-point corrected S-parameters.

[0006] To achieve the above objectives, the present invention provides a method for zero-point correction of an S-parameter model, comprising:

[0007] Calculate the S-parameters when the frequency is zero based on the constructed S-parameter model;

[0008] Calculate the error matrix of the S-parameter model and the original S-parameters at the zero frequency;

[0009] Calculate the residues corresponding to the preset real poles based on the preset real poles and the error matrix;

[0010] By adding a term to the S-parameter model using the preset real poles and their corresponding residues, a zero-corrected S-parameter model is obtained.

[0011] Furthermore, the step of calculating the S-parameters when the frequency is equal to zero based on the constructed S-parameter model also includes,

[0012] The original S-parameter data are subjected to vector fitting and passivity correction to obtain an S-parameter model, which is expressed as follows.

[0013]

[0014] Among them, a kc and C is the k-th pair of complex conjugate poles obtained through fitting. kc and These are the complex conjugate poles a kc and The corresponding residue, N qc It is the logarithm of the complex conjugate poles, a mr It is the m-th real pole, C mr It is a mr The corresponding residue, N qr is the number of real poles, and D is a constant term;

[0015] The S-parameters at zero frequency are calculated based on the S-parameter model, and the S-parameter values ​​of the S-parameter model at zero frequency are obtained as follows.

[0016] S(0) represents the S-parameters of the S-parameter model at a frequency of zero.

[0017] Furthermore, the step of calculating the error matrix of the S-parameter model and the original S-parameters at the zero frequency adopts the following calculation formula:

[0018]

[0019] Where ΔS is the error matrix. S is the value of the original S-parameters when the frequency is zero, and S(0) is the value of the S-parameters of the constructed S-parameter model at the zero frequency.

[0020] Furthermore, the preset real poles are real numbers less than zero.

[0021] Furthermore, the step of calculating the residue corresponding to the preset real pole based on the preset real pole and the error matrix further includes taking the minimum value of the real part of all poles in the S-parameter model and dividing it by a positive number as the preset real pole, wherein the positive number is greater than 1 and less than 10.

[0022] Furthermore, the step of calculating the residue corresponding to the preset real pole based on the preset real pole and the error matrix is ​​performed using the following formula:

[0023] c0=-a0ΔS

[0024] Where c0 is the residue corresponding to the preset real pole, a0 is the preset real pole, and ΔS is the error matrix.

[0025] Furthermore, the zero-point corrected S-parameter model is as follows:

[0026]

[0027] Where S′(f) is the S-parameter after zero correction, a0 is the preset real pole, and c0 is the residue corresponding to the preset real pole.

[0028] To achieve the above objectives, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor is configured to execute the computer program stored in the memory to implement the S-parameter model zero-point correction method as described above.

[0029] To achieve the above objectives, the present invention also provides a computer-readable storage medium storing at least one instruction, which is loaded and executed by a processor to implement the S-parameter model zero-point correction method as described above.

[0030] The S-parameter model zero-point correction method provided by this invention has the following advantages compared with the prior art:

[0031] By adding a pole term to the original S-parameter model, the error of the S-parameters at the zero frequency is corrected, thereby eliminating the error in subsequent simulations caused by the inaccuracy of the S-parameters at the zero frequency.

[0032] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0033] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0034] Figure 1 This is a flowchart of the S-parameter model zero-point correction method according to an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram illustrating the variation of each component of the S-parameter with frequency according to an embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram of the simulation circuit structure for the S-parameter according to an embodiment of the present invention;

[0037] Figure 4 This is a transient simulation voltage waveform diagram without S-parameter zero-point correction according to an embodiment of the present invention;

[0038] Figure 5 The transient simulation voltage waveform is shown in the embodiment of the present invention after S-parameter zero-point correction.

[0039] Figure 6 This is a schematic diagram of an electronic device structure according to an embodiment of the present invention. Detailed Implementation

[0040] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0041] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the invention. It should be understood that the accompanying drawings and embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the invention.

[0042] The term "comprising" and its variations as used herein are open-ended inclusions, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the description below.

[0043] It should be noted that the concepts of "first" and "second" may be mentioned in this invention only to distinguish different devices, components or parts, and are not used to limit the order of the functions performed by these devices, components or parts or their interdependence.

[0044] It should be noted that the terms "one" and "multiple" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless explicitly stated otherwise in the context, they should be understood as "one or more". "Multiple" should be understood as two or more.

[0045] In this embodiment of the invention, a method for zero-point correction of an S-parameter model is provided, comprising:

[0046] Calculate the S-parameters when the frequency is zero based on the constructed S-parameter model;

[0047] Calculate the error matrix of the S-parameter model and the original S-parameters at the zero frequency;

[0048] Calculate the residues corresponding to the preset real poles based on the preset real poles and the error matrix;

[0049] By adding a term to the S-parameter model using the preset real poles and their corresponding residues, a zero-corrected S-parameter model is obtained.

[0050] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0051] Figure 1 The following is a flowchart of the S-parameter model zero-point correction method according to an embodiment of the present invention, which will be referred to below. Figure 1 The method for zero-point correction of the S-parameter model of the present invention will be described in further detail.

[0052] In step 101, the S-parameters of the existing S-parameter model are calculated when the frequency is zero. The S-parameter model is obtained after vector fitting and passivity correction.

[0053] In this embodiment of the invention, for a given dataset i = 1, ..., N, where f i It is the i-th frequency point. It is f i The corresponding S-parameter values ​​are shown, where N is the total number of frequency points and the number of S-parameters. The superscript * indicates that the dataset is raw S-parameter data from an experiment or user. The frequency points are arranged in ascending order, and the first frequency point usually corresponds to a frequency of 0, i.e., f1 = 0.

[0054] The S-parameters can be a matrix whose dimension is equal to the number of ports in the system. Assuming that the system represented by the S-parameters has M ports, then the S-parameters at each frequency point are an M×M matrix.

[0055] After vector fitting and passivity correction, the modeled S-parameters can be written in the following form.

[0056]

[0057] Here a kc and C is the k-th pair of complex conjugate poles obtained through fitting. kc and These are the complex conjugate poles a kc and The corresponding residue, N qc It is the logarithm of the complex conjugate poles. mr It is the m-th real pole, C mr It is its corresponding residue, N qr This represents the number of real poles. D is a constant term.

[0058] It should be noted that since the S-parameters themselves are M×M matrices, all residues and constant terms are also M×M matrices, while the poles are scalars.

[0059] Using formula (1), the S-parameters at any frequency point after modeling can be calculated at the input frequency point, especially at the original frequency point:

[0060] S i =S(f i ), i = 1, 2, ..., N (2)

[0061] S was calculated i and raw data There will be some error, especially at the frequency point of zero.

[0062] In this embodiment of the invention, the S-parameters of the existing model are calculated when the frequency is equal to zero, that is, S(0) = S(f1 = 0) is calculated using formula (1). According to formula (1), S(0) can be expressed as:

[0063]

[0064] In step 102, the error matrix of S(0) and the original S-parameters at the zero point (the frequency point where the frequency is zero) is calculated.

[0065] In this embodiment of the invention, the error matrix ΔS of S(0) and the original S-parameters at the zero point (the frequency point where the frequency is zero) is calculated using the following formula (4).

[0066]

[0067] Given that the pre-established model is relatively accurate, the norm of ΔS will be relatively small. Here, ΔS is an M×M matrix.

[0068] In step 103, a real pole a0 less than zero is preset.

[0069] In this embodiment of the invention, the setting of a0 is somewhat arbitrary. The smaller the absolute value of a0, the smaller the correction to the original model. However, the length of the impulse response obtained after transferring to the time domain will be relatively long, which is not conducive to transient simulation. A0 can be set as the minimum value of the real part of all poles divided by a positive number as the preset real pole.

[0070] Preferably, a0 is set to the minimum value of the real parts of all poles divided by a positive number greater than 1 and less than 10, for example, the minimum value of the real parts of all poles divided by 2, i.e.:

[0071]

[0072] Here, a0 is negative to ensure system stability.

[0073] In step 104, based on the error matrix ΔS and the set real pole a0, the residue corresponding to a0 is calculated. The residue corresponding to a0 is:

[0074] c0=-a0ΔS (6)

[0075] ΔS is defined by formula (4).

[0076] In step 105, the S-parameter model is corrected using the set real pole a0 and its corresponding residue.

[0077] In this embodiment of the invention, based on the set real pole a0 and its corresponding residue, a term is added to the original S-parameter model:

[0078]

[0079] This is equivalent to adding a real pole to the original S-parameter model for correction, and the corrected formula (1) becomes:

[0080]

[0081] Formula (8) will replace Formula (1) for subsequent simulations.

[0082] In this embodiment of the invention, as can be seen from the above process,

[0083]

[0084] That is, the S-parameter values ​​of the corrected model at the zero frequency are exactly the same as those of the original model data.

[0085] The following example illustrates the implementation process of the above method.

[0086] A two-port S-parameter input file is used, containing 1001 frequency points ranging from 0 to 100 GHz. In other words, the original S-parameters contain 1001 S-parameter values, each a 2×2 matrix. This corresponds to the parameters N = 1001 and M = 2.

[0087] Figure 2 This is a schematic diagram illustrating the variation of each component of the S-parameter with frequency according to an embodiment of the present invention, such as... Figure 2 As shown, since the S-parameters are complex numbers, Figure 2 It includes the real part, imaginary part, and absolute value (abs) as a function of frequency (G). Additionally, since the S-parameter in this example is a 2×2 matrix, Figure 2From left to right and top to bottom, the numbers are S11, S12, S21, and S22. It can be seen that the values ​​of S12 and S21 are both 0 at the zero frequency. Therefore, if there is a certain error at the zero frequency after S-parameter modeling, the signal output of S12 or S21 may have a significant impact.

[0088] Figure 3 This is a schematic diagram of the simulation circuit structure for the S-parameter according to an embodiment of the present invention, as shown below. Figure 3 As shown, port 1 is connected to the power supply, and a voltage signal V is applied simultaneously. in Port 2 is connected to the load (a 50-ohm resistor in this embodiment) and then grounded, while its output voltage V is monitored. out Waveform.

[0089] In this invention example, when modeling the S-parameters with 2 ports, vector fitting is performed using different numbers of poles. After passive correction, transient simulation is performed without zero-point correction of the S-parameters. Figure 4 This is a transient simulation voltage waveform diagram without S-parameter zero-point correction according to an embodiment of the present invention. The vertical axis represents voltage, and the horizontal axis represents time. Figure 4 As shown, the transient simulation voltage waveforms of port 2 obtained using 6, 8, 12, and 16 poles respectively show significant differences. This is mainly because different models have different errors at the zero-frequency point, leading to substantial differences in the simulated waveforms.

[0090] The following section uses the zero-point correction method for the S-parameter model described above to perform zero-point correction on the S-parameters. Assume the current S-parameter model is obtained by vector fitting of 10 poles and passivity correction.

[0091] Referring to step 101, a vector fit is performed on the S-parameters using 10 poles. After passivity correction, the S-parameter model is obtained, and the S-parameter values ​​with zero frequencies are calculated.

[0092]

[0093] Referring to step 102, calculate the error matrix of S(0) and the original S-parameters at frequency 0. The original S-parameters at frequency zero have values...

[0094]

[0095] According to formula (4), we can obtain

[0096]

[0097] ΔS represents the modeling error, and its norm is relatively small. At points S11 and S22, due to the large size of the original data, the relative error is approximately 10. -4 The magnitude is small, but at S12 and S21, since the original data is 0, even if the error is 10... -5 The magnitude can also have a significant impact on the output waveform.

[0098] Continuing with step 103, set a new pole a0. According to formula (5) and the pole values ​​obtained from the vector fitting of the original model, we can obtain a0 = -291G. Note that taking 1 / 2 of the minimum real part of all poles is not the only fixed choice; other ratios greater than 1 / 10 and less than 1 can also be taken, such as 1 / 3 or 1 / 5. While ensuring accuracy, the absolute value of a0 should be as large as possible.

[0099] Referring to step 104, based on formula (7) and the ΔS and a0 calculated in steps 102 and 103, calculate the residue of the new pole, and obtain...

[0100]

[0101] Therefore, by adding a new term to the model, we can obtain the S-parameter model after zero-point correction.

[0102] Figure 5 This is a transient simulation voltage waveform diagram after S-parameter zero-point correction according to an embodiment of the present invention. The vertical axis represents voltage, and the horizontal axis represents time. Figure 5 As shown in the figure, the output waveforms of different pole models after S-parameter zero-point correction are displayed. It can be seen that after zero-point correction, the output waveforms of each pole are greatly improved and basically remain consistent. The waveforms corresponding to fewer poles show greater variation, which is because the model error with fewer poles is inherently larger, resulting in greater differences in the output waveforms.

[0103] In the embodiments of the present invention, as shown in Tables 1 and 2 below, Table 1 shows the changes in the relative error of the S-parameters under different poles (i.e., different vector models) without and after correction using the method described above. It can be seen that the error introduced by the method described in the present invention is very small. Table 2 shows the output waveform values ​​of the S-parameter models established with and without S-parameter zero-point correction under different poles at T = 2.5 ns and T = 10 ns after transient simulation. It can be seen that the differences between the various models are significantly reduced after correction.

[0104] Table 1. Variation of relative errors of S-parameters of the original and modified models at different poles.

[0105] number of poles 2 4 6 8 10 12 14 16 Uncorrected 0.0388 0.013 <![CDATA[3.5×10 -3 ]]> <![CDATA[3.3×10 -3 ]]> <![CDATA[6.2×10 -4 ]]> <![CDATA[4.3×10 -4 ]]> <![CDATA[1.6×10 -4 ]]> <![CDATA[8.5×10 -5 ]]> Revised 0.0390 0.012 <![CDATA[3.6×10 -3 ]]> <![CDATA[3.4×10 -3 ]]> <![CDATA[6.5×10 -4 ]]> <![CDATA[4.4×10 -4 ]]> <![CDATA[1.6×10 -4 ]]> <![CDATA[8.6×10 -5 ]]>

[0106] Table 2. Waveform values ​​of the original model and the modified model at different time points in transient simulation under different poles.

[0107]

[0108]

[0109] The zero-point correction method for S-parameter models provided by this invention has the advantage of correcting the error of the original model's S-parameters at the zero-frequency point by adding a pole term to the original model, thereby eliminating the error in subsequent simulations caused by the inaccuracy of the S-parameters at zero frequency. This method further corrects the S-parameters after vector fitting and passivity correction, ensuring that the values ​​of the S-parameter model at zero frequency are consistent with the original S-parameters, while preserving the accuracy and passivity of the zero-point corrected S-parameters as much as possible.

[0110] In embodiments of the present invention, an electronic device is also provided. Figure 6 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention, such as... Figure 6 As shown, the electronic device of the present invention includes a processor 601 and a memory 602, wherein,

[0111] The memory 602 stores a computer program, which, when read and executed by the processor 601, performs the steps described above in the embodiment of the S-parameter model zero-point correction method.

[0112] In embodiments of the present invention, a computer-readable storage medium is also provided, wherein a computer program is stored in the computer program, wherein the computer program is configured to execute the steps in the embodiments of the S-parameter model zero-point correction method as described above when running.

[0113] In this embodiment, the aforementioned computer-readable storage medium may include, but is not limited to, various media capable of storing computer programs, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0114] It will be understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for zero-point correction of an S-parameter model, characterized in that, Includes the following steps: Calculate the S-parameters when the frequency is zero based on the constructed S-parameter model; Calculate the error matrix of the S-parameter model and the original S-parameters at the zero frequency; Calculate the residues corresponding to the preset real poles based on the preset real poles and the error matrix; By adding a term to the S-parameter model using the preset real poles and their corresponding residues, a zero-corrected S-parameter model is obtained. The zero-point corrected S-parameter model is as follows. Where S′(f) are the S-parameters after zero-point correction, a0 is the preset real pole, c0 is the residue corresponding to the preset real pole, and a kc and C is the k-th pair of complex conjugate poles obtained through fitting. kc and These are the complex conjugate poles a kc and The corresponding residue, N qc It is the logarithm of the complex conjugate poles, a mr It is the m-th real pole, C mr It is a mr The corresponding residue, N qr is the number of real poles, and D is a constant term.

2. The method for zero-point correction of the S-parameter model according to claim 1, characterized in that, The step of calculating the S-parameters when the frequency is zero based on the constructed S-parameter model further includes, The original S-parameter data are subjected to vector fitting and passivity correction to obtain an S-parameter model, which is expressed as follows. Among them, a kc and C is the k-th pair of complex conjugate poles obtained through fitting. kc and These are the complex conjugate poles a kc and The corresponding residue, N qc It is the logarithm of the complex conjugate poles, a mr It is the m-th real pole, C mr It is a mr The corresponding residue, N qr is the number of real poles, and D is a constant term; The S-parameters at zero frequency are calculated based on the S-parameter model, and the S-parameter values ​​of the S-parameter model at zero frequency are obtained as follows. S(0) represents the S-parameters of the S-parameter model at a frequency of zero.

3. The method for zero-point correction of the S-parameter model according to claim 1, characterized in that, The step of calculating the error matrix of the S-parameter model and the original S-parameters at a frequency of zero uses the following formula: Where ΔS is the error matrix. S is the value of the original S-parameters when the frequency is zero, and S(0) is the value of the S-parameters of the constructed S-parameter model at the zero frequency.

4. The method for zero-point correction of the S-parameter model according to claim 1, characterized in that, The preset real poles are real numbers less than zero.

5. The method for zero-point correction of the S-parameter model according to claim 4, characterized in that, The step of calculating the residue corresponding to the preset real pole based on the preset real pole and the error matrix further includes taking the minimum value of the real part of all poles in the S-parameter model and dividing it by a positive number as the preset real pole, wherein the positive number is greater than 1 and less than 10.

6. The method for zero-point correction of the S-parameter model according to claim 1, characterized in that, The step of calculating the residue corresponding to the preset real pole based on the preset real pole and the error matrix is ​​performed using the following formula. c0=-a0ΔS Where c0 is the residue corresponding to the preset real pole, a0 is the preset real pole, and ΔS is the error matrix.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor is configured to execute the computer program stored in the memory to implement the S-parameter model zero-point correction method according to any one of claims 1 to 6.

8. A computer-readable storage medium, characterized in that, The storage medium stores at least one instruction, which is loaded and executed by a processor to implement the S-parameter model zero-point correction method according to any one of claims 1 to 6.

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