A calibration device, differential clamp, and related devices and systems

Abstract

Embodiments of the present application provide a calibration device, a differential clamp, and related devices and systems. The calibration device includes a non-equivalent length reflection calibration piece for calibrating a scattering parameter of a differential signal obtained based on the differential clamp. The non-equivalent length reflection calibration piece includes a first line and a second line. An electrical length of the first line is not equivalent to an electrical length of the second line. A difference between a length of the first line and a length of the second line is within a preset range. The preset range is determined based on a bandwidth of the differential signal. Embodiments of the present application can accurately obtain the scattering parameter of the differential signal in the case of using the differential clamp.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a calibration device, differential clamp, and related devices and systems. Background Technology

[0002] With the development of communication technology, the number of differential devices and connectors is increasing, and the transmission rate of differential signals is also improving. However, this increase in transmission rate can lead to signal integrity problems during transmission, such as crosstalk, ringing, ground bounce, and impedance mismatch, resulting in degraded transmission link performance. Therefore, it is necessary to detect the scattering parameters of the differential signals output by these devices to evaluate the performance of the transmission structure. For example, a vector network analyzer can be used for this detection.

[0003] However, the ports of this vector network analyzer are led out via coaxial cables, and in many cases, the relevant differential devices do not have corresponding coaxial connectors to connect to the vector network analyzer. To address this, a differential clamp can be used to connect the connectors of the differential devices to the connectors of the vector network analyzer, allowing the vector network analyzer to detect the differential signals output by the differential devices. However, while the differential clamp achieves the connection between the differential device under test and the vector network analyzer, it also introduces measurement errors.

[0004] To address this measurement error, current methods typically employ through-reflect-line (TRL) calibration to eliminate the error introduced by the differential fixture. However, the TRL calibration method requires specialized calibration components to de-embed the differential fixture. Furthermore, the complex manufacturing process of existing calibration components (e.g., introducing loads into the components) and the inability to eliminate near-end and far-end crosstalk result in low actual calibration accuracy.

[0005] Therefore, how to accurately obtain the scattering parameters of differential signals when using differential fixtures is a technical problem that urgently needs to be solved. Summary of the Invention

[0006] This application provides a calibration device, a differential fixture, and related devices and systems to accurately obtain the scattering parameters of differential signals when using a differential fixture.

[0007] In a first aspect, embodiments of this application provide a calibration device, which may include: a non-uniform length reflection calibration component, the non-uniform length reflection calibration component being used to calibrate and determine the scattering parameters of a differential signal obtained based on a differential fixture; wherein the non-uniform length reflection calibration component includes a first line and a second line, the electrical length of the first line and the electrical length of the second line are not equal, and the difference between the length of the first line and the length of the second line is within a preset range, the preset range being determined based on the bandwidth of the differential signal.

[0008] To ensure the accuracy of the differential signal acquired by the vector network analyzer, when using a differential fixture, it is necessary to de-embed the differential fixture, that is, eliminate the influence of the differential fixture on the differential signal. However, existing calibration devices based on the TRL calibration method cannot eliminate problems such as near-end crosstalk and far-end crosstalk during the calibration process, reducing the calibration accuracy of the TRL calibration method. In response, the first aspect of this application provides a calibration device that can solve this problem. Specifically, the calibration device includes a non-uniform length reflection calibration device, which can be used to calibrate and determine the scattering parameter S of the differential signal. The differential signal is the differential signal acquired based on the differential fixture to be de-embedded and calibrated. The scattering parameter can reflect the transmission characteristics of differential mode, common mode, and differential-common mode conversion when the differential device transmits the differential signal. The non-uniform length reflection calibration component includes two lines (i.e., a first line and a second line), and the difference in length between the two lines is within a preset range. This preset range can be determined based on the bandwidth of the differential signal under test; for example, the preset range can be 2μm-500μm. The bandwidth can refer to the difference between the highest and lowest frequencies of the differential signal under test. During calibration, the first and second lines can be connected to a differential fixture to obtain the scattering parameters corresponding to the differential fixture. The scattering parameters corresponding to the differential fixture can be de-embedded and corrected using a relevant error model after the scattering parameters of the differential signal are subsequently obtained. Most importantly, the two lines have different electrical lengths. The electrical length can be expressed as the ratio of the physical length of the line (i.e., mechanical or geometric length) multiplied by the transmission time of the electric or electromagnetic signal in the line (e.g., time T1) to the time required for the signal to travel a distance equal to the physical length of the line in free space (e.g., time T2). For example, the electrical length of the first line is the length between the first and second ends of the first line multiplied by the ratio of the transmission time of the differential signal in the line to the time required for the differential signal to travel through the length between the first and second ends in free space. Since the electrical lengths of the first and second lines are different, the reflection state coefficients corresponding to the first and second lines are also different. For example, when the reflection state coefficient of the first line is 1, the reflection state coefficient of the second line can be 0.8. Therefore, in subsequent calibration, the error caused by near-end crosstalk and / or far-end crosstalk between the first and second lines can be calculated using a relevant error model. This error can be eliminated during subsequent de-embedding correction of the differential signal's scattering parameters, improving calibration accuracy and allowing for more precise acquisition of the differential signal's scattering parameters when using a differential fixture.

[0009] In one possible implementation, the maximum value within the aforementioned preset range is inversely proportional to the bandwidth of the aforementioned differential signal.

[0010] In this embodiment, the maximum value within the preset range is inversely proportional to the bandwidth of the differential signal. That is, the larger the bandwidth of the differential signal, the smaller the maximum value within the preset range. When the bandwidth of the differential signal to be detected is larger, it indicates greater frequency fluctuation and a greater difference between the two signals. Therefore, to prevent excessive differences between the first and second lines from causing poor calibration accuracy, the maximum value within the preset range is inversely proportional to the bandwidth of the differential signal to ensure high calibration accuracy. Simultaneously, the smaller the maximum value within the preset range, the smaller the difference between the first and second lines.

[0011] In one possible implementation, both the first and second lines are made of metallic conductors.

[0012] In this embodiment, since metallic conductors can conduct electricity, the first and second lines can be made of metallic conductors. For example, they can be made of copper, oxygen-free copper, gold, aluminum, iron, etc. Furthermore, to reduce calibration errors caused by different materials, the materials of the first and second lines must be consistent.

[0013] In one possible implementation, the aforementioned non-uniform reflection calibration element includes two circuit groups, which are axially symmetrically distributed along a first direction; each circuit group includes the first circuit and the second circuit distributed parallel to each other along a second direction, wherein the first direction and the second direction are perpendicular to each other.

[0014] In this embodiment of the application, in order to ensure that the vector network analyzer requires two differential probes to acquire differential signals, the non-equal length reflection calibrator requires two circuit groups to calibrate it. Moreover, in order to ensure the consistency of the signals acquired by the two differential probes, the two circuit groups need to maintain consistency in structure and be axially symmetrically distributed along the first direction to reduce errors.

[0015] In one possible implementation, the first end of the first line and the third end of the second line are flush in the first direction, and the first distance between the second end of the first line and the preset reference surface is not equal to the second distance between the fourth end of the second line and the preset reference surface; both the first distance and the second distance are inversely proportional to the bandwidth of the differential signal, and both the first distance and the second distance are less than or equal to a preset threshold.

[0016] In this embodiment, after determining the preset reference surface, one end of the first line and one end of the second line need to be flush to ensure the consistency of the differential probe in acquiring the differential signal, thereby reducing errors. The different distances of the first line and the second line from the preset reference surface result in different reflection state coefficients for the first and second lines. This helps to determine the errors caused by near-end crosstalk and far-end crosstalk between the first and second lines near the preset reference surface, improving the calibration accuracy of the non-uniform length reflection calibrator and reducing detection errors.

[0017] In one possible implementation, each of the aforementioned line groups further includes a plurality of grounding lines; the plurality of grounding lines are distributed at intervals from the first line and the second line along the first direction, each of the aforementioned grounding lines is distributed parallel to the first line along the second direction, and the fifth end of each of the aforementioned grounding lines is flush with the first end along the first direction.

[0018] In the embodiments of this application, differential probes often have various structures, such as GSSG and GSGSG structures. To make the non-uniform length reflection calibrator applicable to various differential probes, each line group of the non-uniform length reflection calibrator also includes multiple ground lines corresponding to the ground ports of the differential probes. To ensure the consistency of differential signal acquisition at each port of the differential probe, one end of the ground line also needs to be flush with one end of the first and second lines to reduce detection errors.

[0019] In one possible implementation, the differential clamp is a differential probe; the first end of the first line corresponds to the first signal port of the differential probe, and the third end of the second line corresponds to the second signal port of the differential probe; wherein, the differential probe is used to acquire the differential signal output based on the differential clamp through the first signal port and the second signal port, the first signal port is used to acquire a first sub-signal, the second signal port is used to acquire a second sub-signal, and the first sub-signal and the second sub-signal constitute the differential signal.

[0020] In the embodiments of this application, the first and second lines in the non-equal length reflection calibration device correspond to the two signal ports of the differential probe, respectively, to obtain the scattering parameters of the differential signal, thereby reflecting its differential mode, common mode, and differential-common mode conversion transmission characteristics.

[0021] In one possible implementation, the aforementioned non-uniform length reflection calibrator is a non-uniform length open / short circuit calibrator, wherein the first line is short-circuited and the second line is open-circuited, or the first line is open-circuited and the second line is short-circuited.

[0022] In the embodiments of this application, the non-equal length open and short circuit calibration component does not include a load circuit, which can eliminate the processing of matching load. The open and short circuits can be fabricated using conventional circuit etching, avoiding inconsistencies between the two circuit groups in the non-equal length open circuit calibration component due to differences in process technology. This makes it easier to achieve and control the consistency of the two circuit groups in the non-equal length open and short circuit calibration component, and better reduces detection errors.

[0023] In one possible implementation, the aforementioned non-uniform length reflection calibrator is a non-uniform length open-circuit calibrator, and both the aforementioned first circuit and the aforementioned second circuit are open circuits.

[0024] In the embodiments of this application, the non-equal length open circuit calibration component includes two open circuits and does not include a load circuit. This eliminates the need for the matching load processing process. The open circuits can be fabricated using conventional circuit etching, avoiding inconsistencies between the two line groups in the non-equal length open circuit calibration component due to differences in the process. This makes it easier to achieve and control the consistency of the two line groups in the non-equal length open circuit calibration component, and better reduces detection errors.

[0025] In one possible implementation, the aforementioned non-equal length reflection calibrator is a non-equal length short-circuit calibrator, and both the aforementioned first line and the aforementioned second line are short-circuited.

[0026] In the embodiments of this application, the non-equal length short circuit calibrator includes two short circuits and does not include a load circuit. This eliminates the need for the matching load processing and allows the short circuit to be fabricated using conventional circuit etching. This avoids inconsistencies between the two line groups in the non-equal length open circuit calibrator due to differences in the manufacturing process. It makes it easier to achieve and control the consistency of the two line groups in the non-equal length short circuit calibrator, and better reduces detection errors.

[0027] In one possible implementation, the above-mentioned device also includes a through-line calibrator and a delay line calibrator.

[0028] In this embodiment of the application, the calibration device further includes a through calibration component and a delay line calibration component. By setting the delay and loss of the fixture, the influence of the delay and loss of the fixture is eliminated, so that the vector network analyzer determines the error model by measuring the above two transmission standard components and one reflection standard component, thereby reducing the detection error.

[0029] Secondly, embodiments of this application provide a differential fixture, which includes a differential probe and a calibration device electrically connected to the first aspect embodiment, wherein the differential probe is used to acquire a differential signal acquired based on the differential fixture, and the calibration device is used to calibrate and determine the scattering parameters of the differential signal.

[0030] Thirdly, embodiments of this application provide a vector network analyzer, which includes a differential fixture and a calibration device provided in the first aspect embodiment, wherein the differential fixture is used to acquire differential signals, and the calibration device is used to calibrate and determine the scattering parameters of the differential signals.

[0031] Fourthly, embodiments of this application provide a calibration system, which includes a vector network analyzer, a differential probe, and a calibration device provided in the first aspect embodiment, wherein the vector network analyzer acquires a differential signal through the differential probe, and the calibration device is used to calibrate and determine the scattering parameters of the differential signal. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the background art, the accompanying drawings used in the embodiments of this application or the background art will be described below.

[0033] Figure 1 This is a schematic diagram of a detection scenario for a vector network analyzer and a differential device under test, provided in an embodiment of this application.

[0034] Figure 2 These are schematic diagrams of the structures of several differential fixtures provided in the embodiments of this application.

[0035] Figure 3This is a schematic diagram of a calibration system architecture provided in an embodiment of this application.

[0036] Figure 4 This is a schematic diagram of the structure of a calibration device provided in an embodiment of this application.

[0037] Figure 5 This is a schematic diagram of another calibration device provided in the embodiments of this application.

[0038] Figure 6 This is a schematic diagram of the structure of a non-uniform reflection calibration component provided in an embodiment of this application.

[0039] Figure 7 The embodiments of this application are based on Figure 2 A schematic diagram of a non-uniform length reflection calibration component is provided.

[0040] Figure 8 This is a schematic diagram of the circuit group structure of several non-equal length open and short circuit calibration devices provided in the embodiments of this application.

[0041] Figure 9 This is a schematic diagram of the circuit group structure of several non-equal length open circuit calibration components provided in the embodiments of this application.

[0042] Figure 10 This is a schematic diagram of the circuit group structure of several non-equal length short-circuit calibration devices provided in the embodiments of this application.

[0043] Figure 11 This is a schematic diagram of the circuit group structure of another non-equal length short-circuit calibration device provided in the embodiments of this application.

[0044] Figure 12 This is a schematic diagram of the structure of a through calibration component and a delay line calibration component provided in an embodiment of this application.

[0045] Figure 13 This is a schematic diagram of a calibration application scenario based on a through-calibration component provided in an embodiment of this application.

[0046] Figure 14 This is a schematic diagram of a calibration application scenario based on a time delay line calibration component provided in an embodiment of this application.

[0047] Figure 15A This is a schematic diagram of a calibration application scenario based on a non-uniform length reflective calibration component provided in an embodiment of this application.

[0048] Figure 15B This is a schematic diagram of another calibration application scenario based on non-uniform length reflective calibration components provided in the embodiments of this application.

[0049] Figure 16 This is a schematic diagram of an application scenario based on the differential device under test in an embodiment of this application. Detailed Implementation

[0050] The embodiments of this application will now be described with reference to the accompanying drawings.

[0051] The terms "first," "second," "third," "fourth," and "fifth," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0052] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0053] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0054] First, to facilitate understanding of the embodiments of this application, the following detailed analysis of the technical problems to be solved and the application scenarios of the embodiments of this application.

[0055] In existing technologies, differential devices are often measured using a Vector Network Analyzer (VNA). The link information is analyzed by the scattering parameters S of the differential signal output by the VNA. Typically, the VNA's ports are led out from a coaxial line, and calibration is performed before measurement using precise standard or electronic calibration kits to move the calibration reference plane to the end of the coaxial line. However, in many cases, the differential lines of the Devise Under Test (DUT) do not have coaxial connectors at both ends. The docking of the VNA and the DUT requires an additional adapter structure (i.e., a differential clamp). The introduction of this adapter structure makes it impossible for current VNA calibration to measure the true and accurate transmission characteristics of the DUT. A common method is to refer to the appendix... Figure 1 , Figure 1 This is a schematic diagram of a detection scenario involving a vector network analyzer and a differential device under test, provided in an embodiment of this application. Figure 1 As shown, the VNA docks with the DUT via a differential probe, and then calibrates the calibration reference surface to the end of the differential probe through calibration or de-embedding, removing the influence of the differential probe, and finally obtaining the S-parameters of the DUT itself. The calibration device in this embodiment is also applicable to the above scenario.

[0056] It should be noted that differential probes are a type of differential clamp. Please refer to the appendix. Figure 2 , Figure 2 These are schematic diagrams illustrating the structures of several differential fixtures provided in the embodiments of this application. For example... Figure 2 As shown, the differential fixture is a differential probe, which, in addition to the above... Figure 1 The illustrated GSSG structure also includes the GGSSG structure. Furthermore, the differential probe includes multiple ports. For example, the GSSG structure includes four signal probes, each corresponding to one of the four ports of the DUT. For instance, two G-terminal probes are used to acquire the signal output from the DUT's ground terminal; and two S-terminal probes are used to acquire the differential signal output from the DUT's ground terminal. This application does not specifically limit the structure and type of the differential clamp in its embodiments.

[0057] The existing calibration method involves connecting one signal line (e.g., differential) of the differential fixture to different types of calibration components and calibrating the measured S-parameters using the two-port SOLT method. However, this method ignores near-end and far-end crosstalk between channels near the calibration reference plane. For example, a differential probe with a GSSG structure has two S-end probes (as described above). Figure 2As shown, signal probes P and N are used to acquire differential signals. Because signal probes P and N are very close together, near-end crosstalk and far-end crosstalk can occur between the signals acquired by the two probes, and this error cannot be ignored. Furthermore, as the distance between signal probes P and N gradually decreases, or when testing a DUT that outputs a higher frequency differential signal, this error becomes more pronounced, leading to significant deviations in the calibration results.

[0058] To address this issue, this application provides a calibration device. Specifically, the calibration device includes a non-uniform length reflection calibration component, which comprises two lines with unequal electrical lengths (i.e., a first line and a second line). Because the electrical lengths of the first and second lines differ, the reflection state coefficients corresponding to the first and second lines are different. For example, when the reflection state coefficient of the first line is 1, the reflection state coefficient of the second line can be 0.8. Furthermore, during subsequent calibration, the error caused by near-end crosstalk and / or far-end crosstalk between the first and second lines can be calculated using a relevant error model. This error is then eliminated during subsequent de-embedding correction of the differential signal's scattering parameters, improving calibration accuracy and enabling more precise acquisition of the differential signal's scattering parameters when using a differential fixture. The specific structure of this calibration device can be referenced in the following related embodiments, which will not be elaborated upon here.

[0059] Based on the technical problems mentioned above, and in order to facilitate understanding of the embodiments of this application, one of the network architectures on which the embodiments of this application are based will be described below.

[0060] Please see Figure 3 , Figure 3 This is a schematic diagram of a calibration system architecture provided in an embodiment of this application. Figure 3 As shown: The calibration system in this application may include: a vector network analyzer 10, a differential probe 20, and a calibration device 30. Wherein,

[0061] Vector network analyzer 10 is an electromagnetic wave energy testing device. It can measure the amplitude of various parameters of single-port or two-port networks. For example, in this embodiment, the vector network analyzer 10 can measure the differential signal of a differential device under test to determine the performance of the transmission structure of the differential device under test.

[0062] The differential probe 20 is a differential clamp. When the differential device under test lacks a coaxial adapter and cannot be directly connected to the appropriate network analyzer 10, the differential probe 20 can connect the appropriate network analyzer 10 and the differential device under test. This allows the appropriate network analyzer 10 to measure the differential signal of the differential device under test to determine the performance of its transmission structure. For example, in the case of a two-port network being tested by the vector network analyzer 10, to obtain signal consistency, two differential probes with identical structures can be used to measure the differential device under test. The structure of this differential probe can be referenced accordingly above. Figure 2 The embodiments shown are not described in detail in this application.

[0063] The calibration device 30 can be used to eliminate errors introduced by the differential fixture when measuring signals via a differential fixture such as the differential probe 20. For example, in the embodiments of this application, such as Figure 3 The calibration system architecture shown allows the vector network analyzer 10 to calibrate the differential probe 20 by using the calibration device 30 to determine the scattering parameters of the differential signal obtained from the differential probe 20, in order to determine the performance of the transmission structure of the differential device under test.

[0064] Understandable, Figure 3 The calibration system architecture described above is merely an exemplary implementation in this application. The calibration system architecture in this application includes, but is not limited to, the above-described calibration system architecture. For example, when measuring a single-port network with a network analyzer 10, it can be measured using only a single differential probe 20.

[0065] Based on the above calibration system architecture, this application provides a calibration device applied to the above calibration system architecture, so as to accurately obtain the scattering parameters of differential signals when using differential fixtures. Please refer to... Figure 4 , Figure 4 This is a schematic diagram of the structure of a calibration device provided in an embodiment of this application.

[0066] like Figure 4 As shown, the calibration device may include: a non-uniform length reflection calibration component, which is used to calibrate and determine the scattering parameters of the differential signal obtained based on the differential fixture; wherein the non-uniform length reflection calibration component includes a first line and a second line, the electrical length of the first line is not equal to the electrical length of the second line, and the difference between the length of the first line and the length of the second line is within a preset range, the preset range being determined based on the bandwidth of the differential signal.

[0067] It should be noted that the calibration method used in this application involves calibrating or de-embedding the calibration reference surface to the end of the differential fixture, thereby eliminating the influence of the differential fixture and obtaining the true differential signal output by the differential device under test (as described above). Figure 1 (As shown). Therefore, the calibration reference surface can be preset to at least the end of the differential fixture. For example: Figure 4 As shown, the preset reference surface is the pre-set calibration reference surface, which is located at the end of the second line.

[0068] Specifically, such as Figure 4 As shown, the non-uniform length reflection calibration device includes two lines with unequal electrical lengths (i.e., a first line and a second line). The electrical length can be expressed as the ratio of the physical length of the line (i.e., mechanical or geometric length) multiplied by the transmission time of the electrical or electromagnetic signal in the line (e.g., time T1) to the time required for the signal to travel a distance equal to the physical length of the line in free space (e.g., time T2). For example, the electrical length of the first line is the length between the first end and the second end of the first line multiplied by the ratio of the transmission time T1 of the differential signal in the line to the transmission time T2 of the differential signal in free space across the length between the first and second ends. For example, the first line includes a first end a and a second end b; the second line includes a third end c and a fourth end d. Correspondingly, the electrical length of the first line is the length between the first end a and the second end b. The electrical length of the second line is the length between the third terminal c and the fourth terminal d.

[0069] Therefore, the electrical lengths of the first and second lines are different, resulting in different reflection state coefficients for the first and second lines. Furthermore, since the preset calibration surface is located at the end of the second line (position d, the fourth end), when the electrical lengths of the first and second lines are unequal and both are open circuits, the reflection state coefficient of the first line is less than 1, while the reflection state coefficient of the second line is equal to 1. Given this difference in reflection state coefficients, the vector analyzer can determine the impact of near-end crosstalk and far-end crosstalk near the preset reference surface on the measurement data based on the TRL calibration method. Combining this data with the 16 S-parameter data (i.e., scattering parameters) of the DUT itself can improve calibration accuracy. These scattering parameters reflect the transmission characteristics of differential-mode, common-mode, and differential-common-mode conversion when the differential device under test transmits differential signals.

[0070] Furthermore, to ensure calibration accuracy, the resistance and cross-sectional area of ​​the circuit need to remain within a certain range. Therefore, the lengths of the first and second circuits must also fall within a certain range (e.g., the length of the circuit is generally between 150μm and 500μm). The specific length is related to both the resistance and cross-sectional area of ​​the circuit. When the material and resistance of the circuit are constant, the larger the cross-section of the circuit, the longer the length of the circuit.

[0071] It should be noted that since the first and second lines correspond to different signal ports of the differential clamp, and the differential clamp acquires differential signals, the difference between the lengths of the first and second lines must be within a preset range to ensure the basic signal characteristics of the differential signal. This preset range is determined based on the bandwidth of the differential signal. Bandwidth can refer to the difference between the highest and lowest frequencies of the differential signal under test. Optionally, this preset range can also be determined based on the frequency of the differential signal.

[0072] It should also be noted that the non-uniform length reflection calibration component is fabricated on a substrate, which can be a printed circuit board (PCB) or ceramic, etc. This application does not impose specific limitations on this. The material of the substrate needs to be consistent with the material of the substrate corresponding to the differential device under test to reduce errors.

[0073] Optionally, the maximum value in the above preset range is inversely proportional to the bandwidth of the differential signal.

[0074] In this embodiment, the maximum value within the preset range refers to the maximum difference between the first line and the second line, and this maximum value is inversely proportional to the bandwidth of the differential signal. That is, the larger the bandwidth of the differential signal, the smaller the maximum value within the preset range, meaning the smaller the difference between the first line and the second line. When the bandwidth of the differential signal to be detected is larger, it indicates that the frequency fluctuation of the differential signal is greater, and the difference is also greater. Therefore, to prevent the calibration accuracy from being poor due to an excessively large difference between the first line and the second line, the maximum value within the preset range is inversely proportional to the bandwidth of the differential signal to ensure high calibration accuracy. For example, if the bandwidth of the differential signal to be detected is 100 GHz, the maximum value of its preset range can be less than or equal to 12 μm; if the bandwidth of the differential signal to be detected is 10 GHz, the maximum value of its preset range can be less than or equal to 40 μm. This application does not impose specific limitations on this. In addition, to avoid near-end crosstalk and far-end crosstalk during the calibration process, as well as differences in related fabrication processes, the minimum value in the preset range generally needs to be greater than or equal to 2 μm, so that the reflection state coefficient values ​​of the first line and the second line are different.

[0075] Optionally, both the first and second lines mentioned above are made of metal conductors.

[0076] In some embodiments, since metallic conductors can conduct electricity, the first and second lines can be made of metallic conductors. For example, they can be made of copper, oxygen-free copper, gold, aluminum, iron, etc. Furthermore, to reduce calibration errors caused by different materials, at least one of the materials, circuit losses, conductivity, or impedance of the first and second lines is kept consistent. In other embodiments, the first and second lines can be transmission lines. This application does not impose specific limitations on the specific materials of the first and second lines.

[0077] Optionally, the aforementioned non-uniform length reflection calibration component includes two circuit groups, and the two circuit groups are axially symmetrically distributed along a first direction; each circuit group includes the aforementioned first circuit and the aforementioned second circuit distributed parallel to each other along a second direction, wherein the aforementioned first direction and the aforementioned second direction are perpendicular to each other.

[0078] Please see Figure 5 , Figure 5 This is a schematic diagram of another calibration device provided in an embodiment of this application. Figure 5 As shown, to ensure that the vector network analyzer needs two differential fixtures to acquire differential signals when measuring two-port network structures, the corresponding non-uniform length reflection calibration component requires two circuit groups to calibrate the two differential fixtures respectively. Furthermore, to ensure the consistency of the signals acquired by the two differential probes, the non-uniform length reflection calibration component includes two circuit groups. These two circuit groups need to be structurally consistent and axially symmetrically distributed, with their axis of symmetry parallel to the first direction and perpendicular to the second direction. Moreover, to reduce calibration errors, the first and second circuits in each circuit group are distributed parallel to the second direction to prevent crosstalk or inaccurate reflection state coefficients caused by mutual tilting between the first and second circuits, thus avoiding problems such as low calibration accuracy.

[0079] Optionally, the first end of the first line and the third end of the second line are flush in the first direction, and the first distance between the second end of the first line and the preset reference surface is not equal to the second distance between the fourth end of the second line and the preset reference surface; both the first distance and the second distance are inversely proportional to the bandwidth of the differential signal, and both the first distance and the second distance are less than or equal to a preset threshold.

[0080] Taking a circuit group in a non-uniform length reflection calibration component as an example, please refer to... Figure 6 , Figure 6 This is a schematic diagram of the structure of a non-uniform length reflection calibration component provided in an embodiment of this application. Figure 6As shown in (1), when the first end a of the first line and the third end c of the second line are flush in the first direction, the first distance L1 between the second end b of the first line and the preset reference surface and the second distance L2 between the fourth end d of the second line and the preset reference surface are not equal and neither reaches the preset reference surface. This can make the electrical length of the first line and the electrical length of the second line not equal, such as L1 being less than L2, which in turn makes the reflection state coefficient corresponding to the first line different from the reflection state coefficient corresponding to the second line.

[0081] It should be noted that the first distance is the distance between the second end of the first line (the end that is not flush with the second line) and the preset reference plane. Therefore, the first line can be in any of the following states: not reaching the preset reference plane, coinciding with the preset reference plane, or exceeding the preset reference plane, as described above. Figure 6 As shown in (2), the first line is in a state that exceeds the preset reference plane. Similarly, the second line can also be in any of the following states: not reaching the preset reference plane, coinciding with the preset reference plane, or exceeding the preset reference plane.

[0082] Furthermore, it should be noted that, while ensuring the difference between the lengths of the first and second lines is within a preset range, both the first and second distances are less than or equal to a preset threshold. The size of this preset threshold is independent of the size of the preset range. The first and second distances are inversely proportional to the bandwidth of the differential signal; therefore, the preset threshold can also be determined based on the bandwidth of the differential signal. For example, if the bandwidth of the differential signal to be detected is 100 GHz, its preset threshold can be less than or equal to 10 μm; if the bandwidth of the differential signal to be detected is 10 GHz, its preset threshold can be less than or equal to 20 μm. This application does not impose specific limitations on this.

[0083] Furthermore, based on this non-uniform length reflection calibration component, the differential-mode and common-mode reflection coefficients of the differential signal obtained by the vector network analyzer can be respectively:

[0084] Differential mode reflection coefficient:

[0085] Differential common-mode reflection coefficient:

[0086] Where j is the imaginary part, M1 is the reflection state coefficient corresponding to the first line, and M2 is the reflection state coefficient corresponding to the second line. The signs of the reflection state coefficients differ depending on the type of the line. For example, when the first line is open, M1 is greater than 0 and less than or equal to 1; when the first line is short-circuited, M1 is greater than or equal to -1 and less than 0. Similarly, when the second line is open, M2 is greater than 0 and less than or equal to 1; when the second line is short-circuited, M2 is greater than or equal to -1 and less than 0.

[0087] B is the propagation constant, which is determined by the materials of the first and second lines.

[0088] The value of L1 is the first distance between the second end b of the first line and the preset reference surface; the value of L2 is the second distance between the fourth end d of the second line and the preset reference surface. Furthermore, the values ​​of L1 and L2 are negative when the distance does not reach the preset reference surface, zero when they coincide with the preset reference surface, and positive when they exceed the preset reference surface. For example: as described above. Figure 6 As shown in (1), both L1 and L2 are less than 0; as mentioned above Figure 6 As shown in (2), L1 is greater than 0 and L2 is less than 0.

[0089] In addition, to avoid near-end crosstalk and far-end crosstalk during the calibration process, as well as differences in related manufacturing processes, it is necessary to avoid the following in subsequent calculations: when the signs of L1 and L2 are opposite, the sum of L1 and L2 should be 0, or when the signs of L1 and L2 are the same, the subtraction of L1 and L2 should be 0. Therefore, the first distance between the second end of the first line and the preset reference surface is not equal to the second distance between the fourth end of the second line and the preset reference surface, that is, the values ​​of L1 and L2 are also different.

[0090] Therefore, in this application embodiment, a preset reference surface needs to be determined in advance in order to obtain the corresponding differential mode, common mode, or differential-common mode reflection coefficients.

[0091] Furthermore, after determining the preset reference surface, one end of the first and second lines needs to be flush to ensure the consistency of the differential probe in acquiring differential signals, thereby reducing errors. The different distances of the first and second lines from the preset reference surface result in different reflection state coefficients for the first and second lines. This allows for the determination of errors caused by near-end crosstalk and far-end crosstalk between the first and second lines near the preset reference surface, improving the calibration accuracy of non-uniform length reflection calibrators and reducing detection errors.

[0092] Optionally, each of the above-mentioned line groups further includes multiple grounding lines; the multiple grounding lines are distributed at intervals with the first line and the second line along the first direction, each of the above-mentioned grounding lines is distributed parallel to the first line along the second direction, and the fifth end of each of the above-mentioned grounding lines is flush with the first end along the first direction.

[0093] As mentioned above Figure 2 As shown, differential probes often have various structures, such as GSSG and GSGSG structures. To make the non-uniform length reflection calibrator compatible with various differential probes, each line group of the non-uniform length reflection calibrator also includes multiple ground lines, corresponding to the ground ports of the differential probes. Please refer to [link to relevant documentation]. Figure 7 , Figure 7 The embodiments of this application are based on Figure 2 A schematic diagram of a non-uniform length reflection calibration component is provided. (See diagram below.) Figure 7 As shown in Figure (1), each of the above-mentioned line groups also includes multiple grounding lines. In order to ensure the consistency of the differential signal acquired by each port of the differential probe, one end of the grounding line also needs to be flush with one end of the first line and the second line to reduce detection error. It can also be understood that the end of the grounding line that is flush with the first line and the second line is the fifth end.

[0094] In addition, such as Figure 7 The non-uniform reflection calibration piece shown in (1) is suitable for the above. Figure 2 Differential probes with GSSG structures, such as Figure 7 The non-uniform reflection calibration piece shown in (2) is suitable for the above. Figure 2 In the differential probe with a GSGSG structure, the length of the grounding line is not specifically limited in this embodiment. For example, the length of the grounding line can be greater than or less than the length of the first line. Furthermore, the grounding lines of two line groups can be directly connected; this embodiment does not impose specific limitations on this aspect.

[0095] Optionally, the differential fixture is a differential probe; the first end of the first line corresponds to the first signal port of the differential probe, and the third end of the second line corresponds to the second signal port of the differential probe; wherein, the differential probe is used to acquire the differential signal output based on the differential fixture through the first signal port and the second signal port, the first signal port is used to acquire the first sub-signal, the second signal port is used to acquire the second sub-signal, and the first sub-signal and the second sub-signal constitute the differential signal.

[0096] Among them, as mentioned above Figure 2The differential probe of the GSSG structure is shown in the figure. The differential probe includes a first signal port P and a second signal port N. Correspondingly, the differential probe of this GSSG structure is similar to the one described above. Figure 7 In the non-uniform length reflection calibration device shown in (1), the first and second lines correspond to each other, for example: the first signal port P of the differential probe corresponds to the first line, and the second signal port N corresponds to the second line. This allows the scattering parameters of the differential signal to be obtained, thereby reflecting its differential-mode, common-mode, and differential-common-mode conversion transmission characteristics. Furthermore, the first signal port P of the differential probe is used to acquire the first sub-signal, and the second signal port N is used to acquire the second sub-signal, wherein the first sub-signal and the second sub-signal have different phases and can constitute a differential signal.

[0097] It should be noted that the spacing between the first and second lines in each line group of the non-equal length reflection calibration component in the first direction is consistent with the spacing between the first and second signal ports in the corresponding differential probe in the first direction, thereby ensuring the consistency of the reflection coefficient obtained by the differential probe and reducing calibration error.

[0098] Similarly, in the non-equal length reflection calibration fixture, the spacing between adjacent lines in the first direction within each line group must be consistent with the spacing of the corresponding ports of the differential fixture in the first direction.

[0099] Optionally, the aforementioned non-equal length reflection calibration component is a non-equal length open / short circuit calibration component, wherein the aforementioned first line is short circuit and the aforementioned second line is open circuit, or the aforementioned first line is open circuit and the aforementioned second line is short circuit.

[0100] The non-uniform length reflection calibrator in this embodiment is a non-uniform length open / short circuit calibrator, meaning that one of the first and second lines is open and the other is short-circuited. For example, please refer to [link to example document] for a single line group within the non-uniform length open / short circuit calibrator. Figure 8 , Figure 8 This is a schematic diagram of the circuit group structure of several non-equal length open / short circuit calibration devices provided in the embodiments of this application. For example... Figure 8 As shown in Figure (1), the first circuit is short-circuited and the second circuit is open-circuited. Based on the above... Figure 6 According to the relevant description, the first line exceeds the preset reference plane, and the second line coincides with the preset reference plane. Therefore, the differential mode reflection coefficient Sdd11 of this non-equal length open-short circuit calibrator is greater than 0, and the differential common mode reflection coefficient Sdc11 is less than 0. Figure 8 As shown in Figure (2), the first circuit is short-circuited and the second circuit is open-circuited. Based on the above... Figure 6 According to the relevant description, the first line did not reach the preset reference plane, while the second line coincided with the preset reference plane. Therefore, the differential mode reflection coefficient Sdd11 of this non-equal length open-short circuit calibrator is greater than 0, and the differential common mode reflection coefficient Sdc11 is less than 0. Figure 8As shown in (3), the first line is an open circuit and coincides with the preset reference plane, while the second line is a short circuit and exceeds the preset reference plane. Based on the above... Figure 6 According to the relevant description, the differential mode reflection coefficient Sdd11 of this non-equal length open-short circuit calibrator is greater than 0, and the differential common mode reflection coefficient Sdc11 is greater than 0; for example Figure 8 As shown in (4), the first line is an open circuit and coincides with the preset reference plane, while the second line is a short circuit and does not reach the preset reference plane. Based on the above... Figure 6 According to the relevant description, the differential mode reflection coefficient Sdd11 of the non-equal length open-short circuit calibrator is greater than 0, and the differential common mode reflection coefficient Sdc11 is greater than 0.

[0101] It should be noted that the above Figure 8 The circuit group structures of the various non-equal length open / short circuit calibration components shown are merely exemplary embodiments of this application, and the embodiments of this application are not limited to the above-mentioned structures. For example, when the second line is open, the second line may exceed the preset reference plane or not reach the preset reference plane. Another example: when the differential probe is a GSGSG structure, a grounding line also exists between the first line and the second line.

[0102] It should also be noted that, as can be seen from the above formulas for differential mode reflection coefficient and differential common mode reflection coefficient, the above... Figure 8 The circuit group structures of the various non-equal length open / short circuit calibration components shown are only applicable to differential signals where the phase deviation between the first sub-signal and the aforementioned second sub-signal is not 180°.

[0103] It should also be noted that since the non-equal length open and short circuit calibration component does not include a load circuit, the matching load processing process can be omitted. The open and short circuits can be fabricated using conventional circuit etching, thus avoiding inconsistencies between the two circuit groups in the non-equal length open and short circuit calibration component due to differences in the manufacturing process, which could cause calibration errors.

[0104] Optionally, the aforementioned non-uniform length reflection calibration component is a non-uniform length open circuit calibration component, and both the aforementioned first circuit and the aforementioned second circuit are open circuits.

[0105] In this embodiment, the non-uniform length reflection calibrator is a non-uniform length open-circuit calibrator, meaning that both the first and second lines are open circuits. For an example of a line group within the non-uniform length open-circuit calibrator, please refer to [link to relevant documentation]. Figure 9 , Figure 9 This is a schematic diagram of the circuit group structure of several non-equal length open-circuit calibration components provided in the embodiments of this application. Both the first and second circuits are open circuits, such as... Figure 9 As shown in Figure (1), the first line exceeds the preset reference plane, and the second line coincides with the preset reference plane. Based on the above... Figure 6According to the relevant description, the differential mode reflection coefficient Sdd11 of this non-equal length open-circuit calibrator is greater than 0, and the differential common mode reflection coefficient Sdc11 is less than 0; for example Figure 9 As shown in (2), the first line does not reach the preset reference plane, while the second line coincides with the preset reference plane. Based on the above... Figure 6 According to the relevant description, the differential mode reflection coefficient Sdd11 of the non-equal length open circuit calibrator is greater than 0, and the differential common mode reflection coefficient Sdc11 is less than 0.

[0106] This non-equal-length open-circuit calibration component comprises two open circuits and does not include a load circuit, eliminating the need for load matching. The open circuits can be fabricated using conventional circuit etching, avoiding inconsistencies between the two circuit groups due to process differences. This makes it easier to achieve and control the consistency of the two circuit groups, thus reducing detection errors. Furthermore, compared to the aforementioned non-equal-length open-short circuit calibration components, this component is suitable not only for differential signals where the phase deviation between the first and second sub-signals is not 180°, but also for differential signals where the phase deviation between the first and second sub-signals is 180°.

[0107] Optionally, the aforementioned non-equal length reflection calibrator is a non-equal length short-circuit calibrator, and both the aforementioned first line and the aforementioned second line are short-circuited.

[0108] In this embodiment, the non-uniform length reflection calibrator is a non-uniform length short-circuit calibrator, meaning that both the first and second lines are short-circuited. For an example of a group of lines in the non-uniform length short-circuit calibrator, please refer to [link to relevant documentation]. Figure 10 , Figure 10 This is a schematic diagram of the circuit structure of several non-equal-length short-circuit calibration devices provided in the embodiments of this application. Both the first and second circuits are short-circuited, such as... Figure 10 As shown in (1), both the first and second lines exceed the preset reference plane, based on the above. Figure 6 According to the relevant description, the differential mode reflection coefficient Sdd11 of this non-equal length open-circuit calibrator is less than 0, and the differential common mode reflection coefficient Sdc11 is greater than 0; for example Figure 10 As shown in (2), the first line did not reach the preset reference plane, while the second line exceeded the preset reference plane. Based on the above... Figure 6 According to the relevant description, the differential mode reflection coefficient Sdd11 of the non-equal length open circuit calibrator is less than 0, and the differential common mode reflection coefficient Sdc11 is greater than 0.

[0109] This non-equal-length short-circuit calibrator includes two short circuits. Similar to the aforementioned non-equal-length open-short-circuit calibrator and non-equal-length open-circuit calibrator, this non-equal-length short-circuit calibrator also lacks a load circuit, eliminating the need for load matching. The open circuit can be fabricated using conventional circuit etching, making it easier to achieve and control the consistency of the two circuit groups in the non-equal-length short-circuit calibrator, thus reducing detection errors. Furthermore, compared to the aforementioned non-equal-length open-short-circuit calibrator, this non-equal-length short-circuit calibrator, like the non-equal-length open-circuit calibrator, is applicable not only to differential signals where the phase deviation between the first and second sub-signals is not 180°, but also to differential signals where the phase deviation between the first and second sub-signals is 180°.

[0110] It should be noted that the above Figure 8 and Figure 10 In the short-circuit structure of the non-uniform length reflection calibrator shown, the short-circuit length or area between the line and the ground line in the second direction is not specifically limited. For example, one-third or one-quarter of the line length can be shorted. Furthermore, the location of the short-circuit area on the line is generally at the end of the line closer to the preset reference surface, but it can also be located in the middle of the line. This application embodiment does not impose specific limitations on this.

[0111] It should also be noted that the above Figures 8-10 The circuit assembly structure of the non-uniform length reflection calibration component shown is only applicable to the above. Figure 2 The circuit group of the differential probe with the GSSG structure. This application does not specifically limit the distribution and structure of the grounding line, the first line, and the second line in the circuit group. For example: applicable to the above... Figure 2 For example, regarding the circuit group of a differential probe with a GSGGSG structure, please refer to [link / reference]. Figure 11 , Figure 11 This is a schematic diagram of the circuit group structure of another non-equal length short-circuit calibration device provided in an embodiment of this application. For example... Figure 11 As shown, one of the circuit groups in this non-equal-length short-circuit calibrator includes three parallel grounding lines spaced apart, with the first and second lines respectively short-circuited to two adjacent grounding lines. The circuit group structure of this non-equal-length short-circuit calibrator is suitable for the aforementioned... Figure 2 The differential probe has a GSGSG structure. At this time, the differential mode reflection coefficient Sdd11 of the non-equal length short-circuit calibrator is less than 0, and the differential common mode reflection coefficient Sdc11 is greater than 0.

[0112] In one possible implementation, the above-mentioned device also includes a through-line calibrator and a delay line calibrator.

[0113] In this embodiment, the calibration device further includes a through-line calibrator and a delay-line calibrator, enabling the vector network analyzer to determine the error model by measuring the two transmission standards and one reflection standard, thereby reducing detection errors. Both the through-line calibrator and the delay-line calibrator include multiple lines distributed parallel to each other along a second direction, with the length of the lines in the through-line calibrator being shorter than the length of the lines in the delay-line calibrator.

[0114] Please see Figure 12 , Figure 12 This is a schematic diagram of a through-type calibration component and a delay line calibration component provided in an embodiment of this application. Figure 12 As shown in (1), the through calibration component includes multiple lines distributed parallel to each other along the second direction, with both ends of the multiple lines flush with the first direction to facilitate the calibration of the differential fixture. Figure 12 As shown in (2), the delay line calibration component also includes multiple lines distributed parallel to the second direction, with both ends of these multiple lines flush with the first direction, to facilitate the calibration of the differential fixture. From the above... Figure 12 As shown in (1) and (2), the length of the line in the delay line calibration component is greater than the length of the line in the through calibration component, and the number of multiple lines in the through calibration component and the delay line calibration component corresponds one-to-one with the number of ports or probes of the corresponding differential fixture; the spacing between adjacent lines in the multiple lines in the through calibration component and the delay line calibration component is also consistent with the spacing between adjacent ports or probes of the corresponding differential fixture.

[0115] Additionally, it should be noted that when the electrical length of the line in the through-through calibration component is 0, the through-through calibration component has no loss and no reflection, and the corresponding transmission coefficient is 1; when the electrical length is not 0, the characteristic impedance of the through-through standard component must be the same as that of the delay line calibration component, and the loss does not need to be known. If the through-through standard component is used as a reference measurement surface, the specific value of the electrical length must be known. At the same time, if the group delay is set to 0 at this time, the preset reference measurement surface is located in the middle of the through-through standard component.

[0116] It should also be noted that the through calibration component and the delay line calibration component can also be fabricated on a substrate, which can be a printed circuit board (PCB) or ceramic, etc. In this application, the embodiments do not impose specific limitations on this.

[0117] In addition, based on the above Figure 2 The differential probe of the GSSG structure shown above, and the above Figures 4-12 The structure of the calibration device provided in the illustrated embodiment, combined with the calibration method provided in this application, exemplarily illustrates the relevant application scenarios involved in the embodiments of this application.

[0118] The vector network analyzer 10 detects the differential signal of the differential device under test via the differential probe GSSG. To reduce the influence of the differential probe GSSG on the differential signal, the vector network analyzer 10 can first connect a calibration device through the differential probe GSSG to reduce errors.

[0119] The aforementioned vector network analyzer 10 has four coaxial cables leading out, which are respectively connected to two differential probes GSSG. The differential probes GSSG include: two S-end probes (as described above). Figure 2 As shown: signal probes P and N, and two G-end probes, arranged from top to bottom as probe G, signal probe P, signal probe N, and probe G. Please refer to the following for relevant calibration steps. Figures 13-15B Related embodiments.

[0120] Step 1: Please refer to Figure 13 , Figure 13 This is a schematic diagram illustrating a calibration application scenario based on a through-type calibration component, as provided in an embodiment of this application. Figure 13 As shown,

[0121] The through-calibrator is located on the PCB board. This through-calibrator comprises four long, thin metal lines, which can be considered as four lines in this embodiment. Each metal line is 150µm x 75µm in length and width, and the distance between adjacent metal lines is 200µm (this distance is determined by the spacing between adjacent differential probes; in this example, a GSSG200 probe is used). From top to bottom, the four metal lines are ground 1 (001), signal N (002), signal P (003), and ground 2 (004), serving as the through-calibrator. Two differential probes (GSSG) are used, and their four tips are connected to ground 1 (001), signal N (002), signal P (003), and ground 2 (004) of the through-calibrator from the left and right ends, respectively. The other end of the probe is connected to a vector network analyzer 10, allowing testing to begin and obtaining the scattering parameters S corresponding to the through-calibrator.

[0122] Step Two: Please refer to Figure 14 , Figure 14 This is a schematic diagram illustrating a calibration application scenario based on a delay line calibration component, as provided in an embodiment of this application. Figure 14 As shown,

[0123] The delay line calibration component is located on the PCB board in Scenario 1 above. This component also includes four long, strip-shaped metal lines, each 2000µm x 75µm in length and width, with a 200µm spacing between adjacent lines. Its width is consistent with the metal line of the through-calibrator in Step 1. These four metal lines, from top to bottom, are ground 1 (005), signal N (006), signal P (007), and ground 2 (008), serving as the delay line calibration component. Two differential probes (GSSGs) are used, and their four probes are connected to ground 1 (005), signal N (006), signal P (007), and ground 2 (008) of the delay line calibration component from the left and right ends, respectively. The other end of the differential probes (GSSGs) is connected to the vector network analyzer 10, allowing testing to begin and obtain the scattering parameters S corresponding to the delay line calibration component.

[0124] Step 3: Taking the non-uniform length reflection calibrator as an example, please refer to [link to relevant documentation]. Figure 15A , Figure 15A This is a schematic diagram illustrating a calibration application scenario based on a non-uniform length reflective calibration component, as provided in an embodiment of this application. Figure 15A As shown,

[0125] The non-uniform length open circuit calibration component is located on the PCB board and consists of six long strip metal lines: Ground 1 (009), Signal N1 (010), Signal N2 (011), Signal P1 (012), Signal P2 (013), and Ground 2 (014). Each of the six strips is 75µm wide, with a 200µm spacing between adjacent strips. Ground 1 (009) and Ground 2 (014) serve as grounding lines for different line groups, each with a length of 2000µm. Signal N1 (010) and Signal N2 (011) serve as the first line of a different line group, each with a length of 240µm. Signal P1 (012) and Signal P2 (013) serve as the second line of a different line group, each with a length of 140µm. Take two differential probes (GSSGs). Connect the four probes of one GSSG to the corresponding ground 1 (009), signal N1 (010), signal P1 (012), and ground 2 (014) on the left side of the non-uniform length open-circuit calibrator, respectively. Connect the four probes of the other GSSG to the corresponding ground 1 (009), signal N2 (011), signal P2 (013), and ground 2 (014) on the right side of the non-uniform length open-circuit calibrator, respectively. Connect the other side of the differential probes (GSSGs) to the vector network analyzer 10 and begin testing to obtain the scattering parameters S corresponding to the non-uniform length open-circuit calibrator.

[0126] Taking the non-uniform length reflection calibrator as an example of the non-uniform length short-circuit calibrator, please refer to [link / reference]. Figure 15B , Figure 15BThis is a schematic diagram illustrating another calibration application scenario based on a non-uniform length reflective calibration component provided in this application embodiment. For example... Figure 15B As shown,

[0127] The non-uniform length short-circuit calibrator is located on the PCB board and consists of six long strip metal lines: ground 1 (025), signal N1 (026), signal N2 (027), signal P1 (028), signal P2 (029), and ground 2 (030). Each of the six strips is 75µm wide, with a 200µm spacing between adjacent strips. Ground 1 (025) and ground 2 (030) are 2000µm long, signal N1 (026) and signal N2 (027) are 240µm long and are shorted to ground 1 (025), and signal P1 (028) and signal P2 (029) are 140µm long and are shorted to ground 2 (030). Take two differential probes (GSSGs). Connect the four probes of one GSSG to ground 1 (025), signal N1 (026), signal P1 (028), and ground 2 (030) on the left side of the non-equal length short-circuit calibrator. Connect the four probes of the other GSSG to ground 1 (025), signal N2 (027), signal P2 (029), and ground 2 (030) on the right side of the non-equal length short-circuit calibrator. Connect the other side of the differential probes (GSSGs) to the vector network analyzer 10 and begin testing to obtain the scattering parameters S corresponding to the non-equal length open-circuit calibrator.

[0128] It should be noted that the above Figure 15B The illustrated embodiment simply replaces the non-equal length open-circuit calibrator with a non-equal length short-circuit calibrator. In other possible embodiments, the non-equal length reflection calibrator may also be a non-equal length open-short-circuit calibrator, which will not be described in detail in this application.

[0129] Step 4: Please refer to Figure 16 , Figure 16 This is a schematic diagram illustrating an application scenario based on the differential device under test, as described in this application. Figure 16 As shown,

[0130] The differential device under test (DUT) is a four-port unknown differential device on the PCB mentioned above. The DUT has four pads on each side, with each pad measuring 500um x 75um and a spacing of 200um between adjacent pads. The pads on the left end of the DUT, from top to bottom, are Ground 1 (017), Signal N1 (018), Signal P1 (019), and Ground 2 (020). The pads on the right end of the DUT, from top to bottom, are Ground 3 (021), Signal N2 (022), Signal P2 (023), and Ground 4 (024). Take two differential probes GSSG. Connect the four probes of one differential probe GSSG to ground 1 (017), signal N1 (018), signal P1 (019), and ground 2 (020) on the left side of the DUT. Connect the four probes of the other differential probe GSSG to ground 3 (021), signal N2 (022), signal P2 (023), and ground 4 (024) on the right side of the DUT. Connect the other side of the differential probe GSSG to the vector network analyzer 10. Start testing to obtain the four-port scattering parameters S of the DUT with differential fixture.

[0131] Using the above four sets of test data (steps one to four), the 16 S-parameters of the DUT itself are obtained through de-embedding calculation according to the multimode TRL calibration method. This can be understood as follows: based on the test results of through and line, the complex propagation constants of the differential and common modes of the transmission line are calculated, and the propagation constant matrix is ​​obtained by sorting them according to the propagation direction; then, using the test results of the reflector and the propagation constant matrix, the S-parameters of the reflector calibration component itself are calculated in reverse. If the S-parameter Sdd11 > 0, the sign coefficient is 1; if the S-parameter Sdd11 < 0, the sign coefficient is -1. Similarly, if Sdc11 > 0, the sign coefficient is -1; if Sdc11 < 0, the sign coefficient is 1.

[0132] Therefore, in summary, the first aspect of this application provides a calibration device that can accurately obtain the scattering parameters of a differential signal when using a differential fixture. Specifically, the calibration device includes a non-uniform length reflection calibration component, which can be used to calibrate and determine the scattering parameters S of the differential signal. The differential signal is a differential signal to be de-embedded and calibrated based on the differential fixture. The scattering parameters can reflect the transmission characteristics of differential-mode, common-mode, and differential-common-mode conversion when the differential device transmits the differential signal. The non-uniform length reflection calibration component includes two lines (i.e., a first line and a second line), and the difference in length between the two lines is within a preset range. This preset range can be determined according to the bandwidth of the differential signal to be measured; for example, the preset range can be 2μm-500μm. The bandwidth can refer to the difference between the highest and lowest frequencies of the differential signal to be measured. During the calibration process, the first line and the second line can be connected to the differential fixture to obtain the scattering parameters corresponding to the differential fixture. The scattering parameters corresponding to the differential clamp can be de-embedded and corrected using a relevant error model after the scattering parameters of the differential signal are subsequently obtained. Most importantly, the two lines have different electrical lengths. The electrical length can be expressed as the ratio of the physical length of the line (i.e., mechanical or geometric length) multiplied by the transmission time of the electrical or electromagnetic signal in the line (e.g., time T1) to the time required for the signal to travel the same distance in free space as the physical length of the line (e.g., time T2). For example, the electrical length of the first line is the length between the first and second ends of the first line multiplied by the ratio of the transmission time of the differential signal in the line to the time required for the differential signal to travel through the length between the first and second ends in free space. The electrical lengths of the first and second lines differ, resulting in different reflection state coefficients for the first and second lines. For instance, if the reflection state coefficient of the first line is 1, the reflection state coefficient of the second line can be 0.8. Furthermore, in subsequent calibration, the error caused by near-end crosstalk and / or far-end crosstalk between the first and second lines can be calculated using a relevant error model. This error can be eliminated during subsequent de-embedding correction of the differential signal's scattering parameters, improving calibration accuracy and allowing for more precise acquisition of the differential signal's scattering parameters when using a differential fixture.

[0133] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0134] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0135] In the several embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of the units described above is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical or other forms.

[0136] The units described above as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0137] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A calibration device, characterized in that, The device includes: a non-uniform length reflection calibrator, which is used to calibrate and determine the scattering parameters of the differential signal obtained based on the differential fixture; The non-equal length reflection calibration component includes a first line and a second line. The electrical lengths of the first line and the second line are not equal, and the difference between the lengths of the first line and the second line is within a preset range. The preset range is determined based on the bandwidth of the differential signal, and the maximum value in the preset range is inversely proportional to the bandwidth of the differential signal. The electrical length is determined based on the length of the corresponding line and the ratio of the transmission time of the differential signal in the corresponding line to the transmission time in free space over the same length of the corresponding line.

2. The apparatus according to claim 1, characterized in that, Both the first and second lines are made of metallic conductors.

3. The apparatus according to claim 1, characterized in that, The non-uniform length reflection calibration component includes two circuit groups, and the two circuit groups are axially symmetrically distributed along the first direction; Each of the line groups includes a first line and a second line distributed parallel to each other along a second direction, wherein the first direction and the second direction are perpendicular to each other.

4. The apparatus according to claim 3, characterized in that, The first end of the first line and the third end of the second line are flush in the first direction, and the first distance between the second end of the first line and the preset reference surface is not equal to the second distance between the fourth end of the second line and the preset reference surface; Both the first distance and the second distance are inversely proportional to the bandwidth of the differential signal, and both the first distance and the second distance are less than or equal to a preset threshold.

5. The apparatus according to claim 3, characterized in that, Each of the line groups further includes multiple grounding lines; the multiple grounding lines are distributed at intervals with the first line and the second line along the first direction, each grounding line is distributed parallel to the first line along the second direction, and the fifth end of each grounding line is flush with the first end along the first direction.

6. The apparatus according to any one of claims 1-5, characterized in that, The differential clamp is a differential probe; the first end of the first line corresponds to the first signal port of the differential probe, and the third end of the second line corresponds to the second signal port of the differential probe. The differential probe is used to acquire the differential signal output by the differential fixture through the first signal port and the second signal port. The first signal port is used to acquire a first sub-signal, and the second signal port is used to acquire a second sub-signal. The first sub-signal and the second sub-signal constitute the differential signal.

7. The apparatus according to any one of claims 1-5, characterized in that, The non-equal length reflection calibration component is a non-equal length open-short circuit calibration component, wherein the first line is short-circuited and the second line is open-circuited, or the first line is open-circuited and the second line is short-circuited.

8. The apparatus according to any one of claims 1-5, characterized in that, The non-uniform length reflection calibration component is a non-uniform length open circuit calibration component, where both the first and second lines are open circuits.

9. The apparatus according to any one of claims 1-5, characterized in that, The non-equal length reflection calibration device is a non-equal length short circuit calibration device, and both the first line and the second line are short circuits.

10. The apparatus according to any one of claims 1-5, characterized in that, The device also includes a through-line calibrator and a delay line calibrator.

11. A differential fixture, characterized in that, The differential fixture includes a differential probe and a calibration device as described in any one of claims 1-10, wherein the differential probe is used to acquire a differential signal, and the calibration device is used to calibrate and determine the scattering parameters of the differential signal.

12. A vector network analyzer, characterized in that, The vector network analyzer includes a differential fixture and a calibration device as described in any one of claims 1-10, wherein the vector network analyzer uses the differential fixture to acquire differential signals, and the calibration device is used to calibrate and determine the scattering parameters of the differential signals.

13. A calibration system, characterized in that, The system includes a vector network analyzer, a differential probe, and a calibration device as described in any one of claims 1-10, wherein the vector network analyzer is used to acquire a differential signal based on a differential fixture through the differential probe, and the calibration device is used to calibrate and determine the scattering parameters of the differential signal.

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