Frequency response measuring device

Abstract

To provide a frequency characteristics measurement device capable of easily measuring frequency characteristics of a DUT at low cost.SOLUTION: A frequency characteristics measurement device includes: a calibration unit 3 configured to perform SOLT calibration at a cable end surface; a first measurement unit configured to measure an S parameter of a first substrate on which a DUT is mounted after SOLT calibration by the calibration unit 3; a second measurement unit configured to measure the S parameter of a second substrate that has a structure in which a portion on which the DUT is mounted from the first substrate is removed after SOLT calibration by the calibration unit 3; and an extraction unit 5 that is configured to extract the S parameter of the DUT by performing vector calculation on measurement results of the first measurement unit and measurement results of the second measurement unit. The extraction unit 5 regards reflection at a second substrate end surface of each of first fixture and second fixture obtained by virtually dividing the second substrate into two at a center as less than reflection at an end surface of the second substrate when it is not virtually divided into two at the center.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The invention disclosed in this specification relates to a technique for measuring the frequency characteristics of a DUT (Device Under Test).

Background Art

[0002] The frequency characteristics of a DUT are measured by a frequency characteristic measuring device such as a vector network analyzer. In a conventional general measurement method, first, SOLT (Short-Open-Load-Thru) calibration described in Non-Patent Document 1 is performed at the cable end face. Then, a substrate shorted instead of the DUT, a substrate opened instead of the DUT, a substrate with a load mounted instead of the DUT, and a Thru substrate obtained by removing the portion where the DUT is mounted from a sample substrate with the DUT mounted are sequentially attached between the cables, and SOLT calibration is performed. Thereafter, the S-parameters of only the DUT are extracted from the measurement results of the S-parameters of the sample substrate with the DUT mounted. Thereby, the frequency characteristics of a pure DUT can be obtained.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the above-described conventional general measurement method requires four types of calibration substrates, so there are problems that the calibration substrates cost a great deal and the calibration work takes time.

Means for Solving the Problems

[0005] The frequency response measuring apparatus disclosed herein comprises: a calibration unit configured to perform SOLT calibration at the cable end face; a first measuring unit configured to measure the S-parameters of a first substrate on which a DUT is mounted after the SOLT calibration by the calibration unit; a second measuring unit configured to measure the S-parameters of a second substrate after the SOLT calibration by the calibration unit; and an extraction unit configured to extract the S-parameters of the DUT by performing vector calculations on the measurement results of the first measuring unit and the measurement results of the second measuring unit, wherein the extraction unit obtains the S-parameters by virtually dividing the second substrate in half down the middle. The reflections of the first and second fixtures at the end faces of the second substrate are considered to be less than or equal to the reflections at the end faces of the second substrate when it is not virtually divided in the center, the first substrate has a structure in which it is provided with at least one connector on each of its first and second end faces, the second substrate has a structure in which the portion on which the DUT is mounted is removed from the first substrate and any two connectors from all of the connectors provided on the first substrate are selected and connected through, and the number of second substrates is the total number of combinations of selecting two from all of the connectors provided on the first substrate (first configuration).

[0006] In the frequency response measuring apparatus of the first configuration described above, the extraction unit may be configured such that the amplitude of the S-parameter indicating the reflection of the first fixture at the end face of the second substrate is set to a single first fixed value over the entire frequency range of the measurement range, the phase of the S-parameter indicating the reflection of the first fixture at the end face of the second substrate is set to zero over the entire frequency range of the measurement range, the amplitude of the S-parameter indicating the reflection of the second fixture at the end face of the second substrate is set to the first fixed value over the entire frequency range of the measurement range, and the phase of the S-parameter indicating the reflection of the second fixture at the end face of the second substrate is set to zero over the entire frequency range of the measurement range (second configuration).

[0007] In the frequency response measuring apparatus of the first or second configuration described above, the extraction unit may be configured such that the transmission characteristics of the first fixture and the transmission characteristics of the second fixture are considered to be symmetrical (third configuration).

[0008] In the frequency response measuring apparatus of the first or second configuration described above, the extraction unit may be configured in a way that does not consider the transmission characteristics of the first fixture and the transmission characteristics of the second fixture to be symmetrical (fourth configuration).

[0009] In a frequency response measuring device of any of the above configurations 1 to 4, the distance between the two end faces to which the cable of the second substrate is connected may be less than twice the reciprocal of the lowest frequency in the measurement range (fifth configuration).

[0010] The computer program disclosed herein is a computer program for processing measurement results of a frequency response measuring apparatus comprising: a calibration unit configured to perform SOLT calibration at the cable end face; a first measurement unit configured to measure the S-parameters of a first substrate on which a DUT is mounted after the SOLT calibration by the calibration unit; and a second measurement unit configured to measure the S-parameters of a second substrate after the SOLT calibration by the calibration unit, wherein the computer is configured to perform vector operations on the S-parameters of the DUT by a first acquisition unit for acquiring the measurement results of the first measurement unit, a second acquisition unit for acquiring the measurement results of the second measurement unit, and the S-parameters of the DUT by performing vector operations on the measurement results of the first measurement unit and the measurement results of the second measurement unit. The extraction unit is configured to extract the following, and the extraction unit considers the reflections at the end faces of the second substrate of the first and second fixtures obtained by virtually dividing the second substrate in half down the center to be less than or equal to the reflections at the end faces of the second substrate when it is not virtually divided in half down the center, the first substrate has a structure in which at least one connector is provided on each of the first and second end faces, the second substrate has a structure in which the portion on which the DUT is mounted is removed from the first substrate and any two connectors are selected from all the connectors provided on the first substrate and connected through, and the number of second substrates is the total number of combinations of selecting two from all the connectors provided on the first substrate (sixth configuration). [Effects of the Invention]

[0011] According to the invention disclosed in this specification, the frequency characteristics of the DUT can be measured at low cost and easily.

Brief Description of the Drawings

[0012] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a frequency characteristic measuring apparatus according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram showing a schematic structure of a first substrate. [Figure 3] FIG. 3 is a schematic diagram showing a schematic structure of a second substrate. [Figure 4] FIG. 4 is a flowchart showing an operation example of an extraction unit. [Figure 5] FIG. 5 is a diagram schematically showing S parameters of a first fixture. [Figure 6] FIG. 6 is a diagram schematically showing S parameters of a second fixture. [Figure 7] FIG. 7 is a diagram schematically showing S parameters of a second substrate.

Embodiments for Carrying Out the Invention

[0013] FIG. 1 is a block diagram showing a schematic configuration of a frequency identification measuring apparatus according to an embodiment. The frequency characteristic measuring apparatus 10 (hereinafter abbreviated as "frequency characteristic measuring apparatus 10") according to the embodiment shown in FIG. 1 is a vector network analyzer.

[0014] The frequency characteristic measuring apparatus 10 includes a first port 1, a second port 2, a calibration unit 3, a measurement unit 4, and an extraction unit 5.

[0015] The first port 1 is configured such that one end E11 of the first coaxial cable CX1 can be connected. The second port 2 is configured such that one end E21 of the second coaxial cable CX2 can be connected.

[0016] The calibration unit 3 is configured to perform SOLT calibration on the cable end faces. Specifically, with one end E11 of the first coaxial cable CX1 connected to the first port 1 and one end E21 of the second coaxial cable CX2 connected to the second port 2, the calibration unit 3 is configured to perform SOLT calibration on the end face of the other end E12 of the first coaxial cable CX1 and the end face of the other end E22 of the second coaxial cable CX2, respectively. Since the SOLT calibration on the cable end face is a well-known technique disclosed in, for example, Non-Patent Document 1, a detailed description thereof is omitted here. The calibration unit 3 provides the calibration result to the measurement unit 4.

[0017] The measurement unit 4 measures the S parameters. The measurement unit 4 functions as both a first measurement unit and a second measurement unit.

[0018] The first measurement unit is configured to measure the S parameters of the first substrate SUB1 (see FIG. 2) on which the DUT is mounted after the SOLT calibration by the calibration unit 3. That is, when the first measurement unit executes the measurement, the first substrate SUB1 is connected to the frequency characteristic measurement device 10 via the first coaxial cable CX1 and the second coaxial cable CX2.

[0019] The second measurement unit is configured to measure the S parameters of the second substrate SUB2 (see FIG. 3), which has a structure in which the portion where the DUT is mounted is removed from the first substrate SUB1, after the SOLT calibration by the calibration unit 3. That is, when the second measurement unit executes the measurement, the second substrate SUB2 is connected to the frequency characteristic measurement device 10 via the first coaxial cable CX1 and the second coaxial cable CX2.

[0020] FIG. 2 is a schematic diagram showing the schematic structure of the first substrate SUB1. FIG. 3 is a schematic diagram showing the schematic structure of the second substrate SUB2. The first substrate SUB1 has a portion P1 where the DUT is mounted, a first fixture P2, and a second fixture P3. The second substrate SUB2 has a first fixture P2 and a second fixture P3. In the second substrate SUB2, the first fixture P2 and the second fixture P3 can be obtained by virtually dividing the second substrate SUB2 into two at the center.

[0021] The first fixture P2 has a first connector CN1 that can be connected to the other end E12 of the first coaxial cable CX1. The first connector CN1 is located at the left end of the first fixture P2. The second fixture P3 has a second connector CN2 that can be connected to the other end E22 of the second coaxial cable CX1. The second connector CN2 is located at the right end of the second fixture P3. The first fixture P2 and the second fixture P3 have a symmetrical structure. However, the first fixture P2 and the second fixture P3 are not perfectly symmetrical and may have some manufacturing variations.

[0022] The extraction unit 5 is configured to extract the S-parameters of the DUT by performing vector operations on the measurement results of the first measurement unit and the measurement results of the second measurement unit. The extraction results of the extraction unit 5 may be stored in a portable storage medium that can be attached to or detached from the frequency response measuring device 10, displayed on a display unit provided on the frequency response measuring device 10, or output to the outside of the frequency response measuring device 10 via communication.

[0023] The extraction unit 5 can be realized, for example, by installing a computer program on a computer such as a microcomputer to process the measurement results of the first measurement unit and the measurement results of the second measurement unit, and then executing the computer program. In this embodiment, the extraction unit 5 is built into the frequency response measuring device 10, but a computer provided outside the frequency response measuring device 10 may also function as the extraction unit 5.

[0024] Figure 4 is a flowchart illustrating an example of the operation of the extraction unit 5. First, the extraction unit 5 acquires the measurement result from the first measurement unit (step S10). Next, the extraction unit 5 acquires the measurement result from the second measurement unit (step S20). In this embodiment, however, step S20 may be executed first, followed by step S10, or steps S10 and S20 may be executed in parallel.

[0025] After obtaining the measurement results from the first measurement unit and the second measurement unit, the extraction unit 5 extracts the S-parameters of the DUT by performing a vector operation on the measurement results from the first measurement unit and the second measurement unit (step S30), and then terminates the flow operation.

[0026] Next, the details of the process in step S30 will be described. Figure 5 schematically shows the S-parameters of the first fixture P2. Figure 6 schematically shows the S-parameters of the second fixture P3. Figure 7 schematically shows the S-parameters of the second substrate SUB2.

[0027] Due to the left-right symmetry between the first fixture P2 and the second fixture P3, the extraction unit 5 sets S21A = S12B and S12A = S21B. Furthermore, the extraction unit 5 considers the reflection at the second substrate end face of each of the first fixture P2 and the second fixture P3 to be less than or equal to the reflection at the end face of the second substrate SUB2, but does not consider the reflection at the virtual dividing surface of each of the first fixture P2 and the second fixture P3 to be less than or equal to the reflection at the end face of the second substrate SUB2. Note that "considering the reflection at the second substrate end face of each of the first fixture P2 and the second fixture P3 to be less than or equal to the reflection at the end face of the second substrate SUB2" means that, in the frequency range of the measurement range, the reflection at the second substrate end face of each of the first fixture P2 and the second fixture P3 should be considered to be less than or equal to the reflection at the end face of the second substrate SUB2, either generally or completely. In other words, this does not exclude cases in the frequency range of the measurement range where the reflection at the end face of the second substrate of the first fixture P2 and the second fixture P3 is partially higher than the reflection at the end face of the second substrate SUB2. The extraction unit 5 then determines the S-parameters of the first fixture P2 and the S-parameters of the second fixture P3 from the measurement results of the second measurement unit. Specifically, the S-parameters of the first fixture P2 and the S-parameters of the second fixture P3 are as follows. (1) The amplitude of S11A (the S-parameter indicating the reflection at the second substrate end face of the first fixture P2) is a single first fixed value across the entire frequency range of the measurement range. (2) The phase of S11A is zero across the entire frequency range of the measurement. (3) S22A = (S22C - S11A) / S12C (4) S21A = (1 - S11B 2 ×S21C) 0.5 (5) S12A = (1 - S22A 2 ×S12C) 0.5 (6) S11B = (S11C - S11A) / S21C (7) The amplitude of S22B (the S-parameter indicating the reflection at the second substrate end face of the second fixture P3) is a single first fixed value across the entire frequency range of the measurement range. (8) The phase of S22B is zero across the entire frequency range of the measurement. (9) S21B = S12A (10) S12B = S21A

[0028] The extraction unit 5 subtracts the S-parameters of the first fixture P2 and the S-parameters of the second fixture P3 from the measurement results of the first measurement unit using vector calculations to obtain the S-parameters of the DUT only.

[0029] Measurements using the frequency response measuring device 10 do not require a shorted circuit board, an open circuit board, or a circuit board with a load mounted on it instead of a DUT. Therefore, the frequency response measuring device 10 can measure the frequency characteristics of a DUT easily and at low cost.

[0030] If the S-parameter S11A of the first fixture P2 is a value indicating low reflectivity, then if the DUT has high transmittance characteristics, the S-parameter S11 of the first substrate SUB1 will be almost entirely determined by the S-parameter S11B of the second fixture P3. Conversely, if the DUT has high reflectivity characteristics, the S-parameter S11 of the first substrate SUB1 will be almost entirely determined by the S-parameter S11 of the DUT. We have explained two extreme cases: when the DUT has high transmittance characteristics and when the DUT has high reflectivity. However, even in other cases, the S-parameter S11 of the first substrate SUB1 will be almost entirely determined by the S-parameter S11B of the second fixture P3 and the S-parameter S11 of the DUT.

[0031] Similarly, if the S-parameter S22B of the second fixture P3 is a value indicating low reflectivity, then if the DUT has high transmittance characteristics, the S-parameter S22 of the first substrate SUB1 will be almost entirely determined by the S-parameter S22A of the first fixture P2. Conversely, if the DUT has high reflectivity characteristics, the S-parameter S22 of the first substrate SUB1 will be almost entirely determined by the S-parameter S22 of the DUT. We have described two extreme cases: when the DUT has high transmittance characteristics and when the DUT has high reflectivity. However, even in other cases, the S-parameter S22 of the first substrate SUB1 will be almost entirely determined by the S-parameter S22A of the first fixture P2 and the S-parameter S22 of the DUT.

[0032] In other words, it is reasonable for the extraction unit 5 to consider the reflections at the second substrate end faces of the first fixture P2 and the second fixture P3 to be below a predetermined level across the entire frequency range of the measurement.

[0033] Similar to the frequency response measurement device 10, a measurement device that does not require a shorted board instead of a DUT, an open board instead of a DUT, or a board with a load mounted instead of a DUT is disclosed in “Design criteria of automatic fixture removal (AFR) for asymmetric fixture dembedding” (IEEE Conference Paper, pp. 654-659, August 2014). However, it is presumed that the virtual division between the first and second fixtures described in Fig. 2 of “Design criteria of automatic fixture removal (AFR) for asymmetric fixture dembedding” (IEEE Conference Paper, pp. 654-659, August 2014) cannot be properly performed unless the distance between the two end faces to which the cables of the second board SUB2 are connected is at least twice the reciprocal of the lowest frequency in the measurement range. On the other hand, in the frequency response measuring device 10, in order to determine each of the S parameters (1) to (10) above, the distance between the two end faces to which the cables of the second substrate SUB2 are connected does not need to be more than twice the reciprocal of the lowest frequency in the measurement range. Therefore, from the viewpoint of miniaturizing and reducing the cost of the second substrate SUB2, it is preferable that the distance between the two end faces to which the cables of the second substrate SUB2 are connected is less than twice the reciprocal of the lowest frequency in the measurement range.

[0034] In the embodiment described above, the extraction unit 5 assumed that the permeability characteristics of the first fixture P2 and the permeability characteristics of the second fixture P3 were symmetrical. However, the extraction unit 5 does not have to assume that the permeability characteristics of the first fixture P2 and the permeability characteristics of the second fixture P3 are symmetrical. If the extraction unit 5 does not assume that the permeability characteristics of the first fixture P2 and the permeability characteristics of the second fixture P3 are symmetrical, then (9) above changes to (9)' below, and (10) above changes to (10)' below. (9)'S21B=(1-S11B 2 ×S21C) 0.5 (10)'S12B=(1-S22A 2 ×S12C) 0.5

[0035] In the embodiment described above, the first substrate SUB1 has a structure that includes two connectors (first connector CN1 and second connector CN2), but the number of connectors provided on the first substrate SUB1 may be three or more.

[0036] In other words, the first board SUB1 only needs to have a structure that includes at least one connector on each of its first and second end faces. The second board SUB2 only needs to have a structure that removes the portion on which the DUT is mounted from the first board SUB1 and connects any two connectors from all the connectors provided on the first board SUB1 through. The number of second boards SUB2 is the total number of combinations of selecting two connectors from all the connectors provided on the first board SUB1.

[0037] The following outlines the measurement procedure, using the example of a first substrate SUB1 having a structure with four connectors (connectors 1 to 4).

[0038] If the first board SUB1 has a structure with four connectors (first to fourth connectors), then the number of connectors on the second board SUB2 will be six (=4C2).

[0039] The first second board, SUB2, has a structure in which the portion on which the DUT is mounted is removed from the first board SUB1, and the first connector and the second connector provided on the first board SUB1 are connected through.

[0040] The second board, SUB2, has a structure in which the portion on which the DUT is mounted is removed from the first board SUB1, and the first connector and third connector provided on the first board SUB1 are connected through.

[0041] The third board, SUB2, has a structure in which the portion on which the DUT is mounted is removed from the first board SUB1, and the first connector and the fourth connector provided on the first board SUB1 are connected through.

[0042] The fourth board, SUB2, is constructed by removing the portion on which the DUT is mounted from the first board SUB1 and through-connecting the second and third connectors provided on the first board SUB1.

[0043] The fifth board, SUB2, is constructed by removing the portion on which the DUT is mounted from the first board SUB1 and through-connecting the second and fourth connectors provided on the first board SUB1.

[0044] The sixth board, SUB2, is constructed by removing the portion on which the DUT (Device Under Test) is mounted from the first board, SUB1, and through-connecting the third and fourth connectors provided on the first board, SUB1.

[0045] Similar to the embodiment described above, a virtual division is performed for each of the 1st to 6th second substrates SUB2, the S-parameters of the first fixture and the S-parameters of the second fixture are determined, and the S-parameters of the DUT only are determined using the S-parameters of the first fixture and the S-parameters of the second fixture.

[0046] Now, let's focus on the first and second SUB2 boards. The S-parameters of the first fixture on the first SUB2 board are S11A, S12A, S21A, and S22A. Also, the S-parameters of the second fixture on the first SUB2 board are S11B, S12B, S21B, and S22B. The S-parameters of the first fixture on the second SUB2 board are S11A, S31A, S13A, and S33A. Also, the S-parameters of the second fixture on the second SUB2 board are S11B, S31B, S13B, and S33B. Therefore, S11B can be found from the first SUB2 board and also from the second SUB2 board.

[0047] Thus, the diagonal components of the S-parameters are obtained redundantly. Therefore, for each of the redundantly obtained diagonal components, a criterion is established, such as adopting the one with the highest reflection, or using an average, and the value of each diagonal component is determined based on that criterion.

[0048] Furthermore, after the values ​​of each diagonal component have been determined, the values ​​of each off-diagonal component may be recalculated. Then, the values ​​of each off-diagonal component before recalculation and the values ​​of each off-diagonal component after recalculation are compared, and a criterion such as adopting the one with the highest reflection or using averaging is established, and the values ​​of each off-diagonal component are finally determined based on that criterion.

[0049] Furthermore, if the number of ports on the frequency response measuring device is greater than the number of connectors on the first board SUB1, the unused ports on the frequency response measuring device should be terminated with 50Ω. [Explanation of Symbols]

[0050] 1. Port 1 2. Port 2 3. Proofreading Department 4 Measuring part 5 Extraction part 10 Frequency determination measuring device according to one embodiment CN1 First Connector CN2 Second Connector CX1 First Coaxial Cable CX2 Second Coaxial Cable E11 One end of the first coaxial cable E12 The other end of the first coaxial cable E21 Second coaxial cable, one end E22 Second coaxial cable, other end The part where P1 DUT is implemented P2 First Fixture P3 Second Fixture SUB1 First board SUB2 Second board

Claims

1. A calibration unit configured to perform SOLT calibration at the cable end face, A first measuring unit is configured to measure a plurality of first S parameters of the first substrate, including a first fixture, a second fixture, and a DUT, after the SOLT calibration by the calibration unit. A second measuring unit is configured to measure a plurality of second S parameters of a second substrate, including the first and second fixtures, after the SOLT calibration by the calibration unit, Extraction section, Equipped with, The extraction unit is The amplitude of one of the multiple third S-parameters of the second fixture on the second substrate is set to a first fixed value over the entire frequency range of the measurement range. The phase of one of the aforementioned multiple third S-parameters is set to zero over the entire frequency range of the measurement range. Based on the setting of the amplitude of one of the plurality of third S parameters, the setting of the phase of one of the plurality of third S parameters, and the plurality of second S parameters, the plurality of third S parameters are determined. Based on the plurality of second S parameters and the plurality of third S parameters, a plurality of fourth S parameters of the second substrate are determined. Based on the plurality of first S parameters, the plurality of third S parameters, and the plurality of fourth S parameters, a vector operation is performed. In the aforementioned vector operation, multiple fifth S parameters of the DUT are extracted, The extraction unit is The reflections at the end faces of the second substrate, obtained by virtually dividing the second substrate in half down the center, for both the first fixture and the second fixture of the second substrate, are considered to be less than or equal to the reflections at the end faces of the second substrate when it is not virtually divided in half down the center. The first substrate has a structure that includes at least one connector on each of its first and second end faces, The second board has a structure in which the portion on which the DUT is mounted is removed from the first board, the first fixture and the second fixture are directly connected, and any two of the connectors provided on the first board are selected and connected through. A frequency response measuring device in which the number of the second substrates is the total number of combinations of selecting two connectors from all the connectors provided on the first substrate.

2. The extraction unit is The amplitude of one of the plurality of fourth S-parameters is set to the first fixed value over the entire frequency range of the measurement range. The phase of one of the aforementioned multiple fourth S-parameters is set to zero over the entire frequency range of the measurement range. One of the plurality of third S parameters indicates the reflection of the first fixture at the end face of the second substrate, The frequency response measuring apparatus according to claim 1, wherein one of the plurality of fourth S parameters indicates the reflection of the second fixture at the second substrate end face.

3. The extraction unit is The frequency response measuring apparatus according to claim 1 or claim 2, wherein the transmission characteristics of the first fixture and the transmission characteristics of the second fixture are considered to be symmetrical.

4. The extraction unit is The frequency response measuring apparatus according to claim 1 or claim 2, wherein the transmission characteristics of the first fixture and the transmission characteristics of the second fixture are not considered to be symmetrical.

5. The frequency response measuring device according to any one of claims 1 to 4, wherein the distance between the two end faces to which the cable of the second substrate is connected is less than twice the reciprocal of the lowest frequency in the measurement range.

6. A calibration unit configured to perform SOLT calibration at the cable end face, A first measuring unit is configured to measure a plurality of first S parameters of the first substrate, including a first fixture, a second fixture, and a DUT, after the SOLT calibration by the calibration unit. A second measuring unit is configured to measure a plurality of second S parameters of a second substrate, including the first and second fixtures, after the SOLT calibration by the calibration unit, A computer program for processing measurement results of a frequency response measuring device comprising: A step of obtaining the measurement result of the first measuring unit, A step of obtaining the measurement result of the second measuring unit, A step of setting the amplitude of one of the multiple third S-parameters of the second fixture of the second substrate to a first fixed value over the entire frequency range of the measurement range. The step of setting the phase of one of the S parameters to zero over the entire frequency range of the measurement range, A step of setting the amplitude of one S-parameter, setting the phase of one S-parameter, and determining the plurality of third S-parameters based on the plurality of second S-parameters, A step of determining a plurality of fourth S parameters of the second substrate based on the plurality of second S parameters and the plurality of third S parameters, and A step of performing a vector operation based on the plurality of first S parameters, the plurality of third S parameters, and the plurality of fourth S parameters. Have the computer run it, In the aforementioned vector operation, multiple fifth S parameters of the DUT are extracted, When processing the measurement results of the frequency response measuring device, the reflections at the end faces of the second substrate, for both the first fixture and the second fixture of the second substrate obtained by virtually dividing the second substrate in half down the center, are considered to be less than or equal to the reflections at the end faces of the second substrate when it is not virtually divided in half down the center. The first substrate has a structure that includes at least one connector on each of its first and second end faces, The second board has a structure in which the portion on which the DUT is mounted is removed from the first board, the first fixture and the second fixture are directly connected, and any two of the connectors provided on the first board are selected and connected through. A computer program in which the number of the second circuit boards is the total number of combinations of selecting two connectors from all the connectors provided on the first circuit board.

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