Calibrator and calibration method for multi-port waveguide antenna test system, and test method and test system for multi-port waveguide antenna

Abstract

The invention provides a calibration piece and a calibration method for a multi-port waveguide antenna test system, and a test method and a test system for a multi-port waveguide antenna, in the calibration piece, a positioning structure can ensure the repeatability of each connection, which is the premise of high-precision calibration, and the calibration accuracy is greatly improved. The load unit, the offset short circuit unit and the offset load unit are provided with a plurality of waveguide ports which are the same as those of a tested piece and can be directly butted, the internal structure of the waveguide port of the load unit is an antenna, electromagnetic wave energy can be radiated out instead of being absorbed internally, and high precision and stability of the load standard are guaranteed; according to the method, the reference surface can be determined at the interface of the tested piece, the calibration error model can be directly tested on the reference surface, the accuracy is good, and the solved calibration error model contains all time-varying characteristics of the whole test link during each calibration, so that the method can be used for frequently calibrating according to requirements, and the calibration accuracy is high. Measurement errors caused by temperature drift and link loss can be handled, and the efficiency is high.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and in particular to a calibration component, calibration method, test method and test system for a multi-port waveguide antenna test system. Background Technology

[0002] Multiport waveguide antennas are a key technology for achieving multi-functionality and multi-beam capabilities in millimeter-wave radar. Utilizing waveguide structures, they control signal transmission and reception through multiple ports, providing radar systems with more precise detection, tracking, and imaging capabilities. They hold particular promise for applications in autonomous driving, intelligent transportation, and robot navigation. Production lines for multiport waveguide antennas require rapid and stable testing of key parameters such as port reflection S11 parameters and VSWR. Unlike single-port coaxial antennas, multiport waveguide antennas contain multiple independent radiating ports (or feed ports), resulting in complex test links typically including waveguide switching matrices and waveguide conversion fixtures. These introduced components introduce losses, mismatches, and time-varying factors, making calibration and de-embedding essential prerequisites for quality control.

[0003] Because multi-port waveguide antennas typically use non-standard, customized interfaces (such as small-section ridge waveguides), readily available calibration standards are lacking, making it difficult to implement the linear independent standard required for a one-port three-term error model on the DUT interface reference plane. In existing technologies, the calibration and de-embedding methods for multi-port waveguide antenna testing typically involve: calibrating at a standard waveguide interface (such as WR10 / WR12) on the output of a vector network analyzer (VNA) or switch matrix to establish a preliminary reference plane; using a "simulation + baseline correction" approach, first obtaining the simulation S-parameter file of the waveguide conversion fixture through full-wave simulation, then correcting its amplitude and phase using a "dry test / metal part" baseline to obtain the corrected S-parameter file; during testing, based on the port load relationships in the corrected S-parameter file, the reference plane is moved from the preliminary reference plane to the interface of the device under test (DUT) using a de-embedding algorithm.

[0004] However, this existing technology has the following drawbacks: Simulation and offline calibration methods cannot overcome the performance deviation between simulation and physical waveguide conversion fixtures caused by factors such as assembly tolerances, flange torque, wear, and oxidation. This results in the corrected S-parameter file used for de-embedding not matching the actual situation. The final measurement result is the composite performance of the "waveguide conversion fixture + DUT". The de-embedding algorithm is extremely sensitive to the S-parameter error of the waveguide conversion fixture. Even a small error can cause serious distortion of the measured value of the DUT's performance, failing to accurately reflect the DUT antenna performance. Components such as the waveguide switch matrix and waveguide conversion fixture will experience performance drift (temperature drift, aging, etc.) due to factors such as temperature, mechanical fatigue, and clamping force, leading to a decrease in de-embedding accuracy. In order to maintain accuracy, frequent interruptions of testing and recalibration and characterization of the waveguide conversion fixture are necessary, which severely restricts production efficiency and introduces connection repeatability risks and operational uncertainties.

[0005] In summary, traditional calibration methods for multi-port waveguide antenna testing suffer from technical problems such as poor accuracy and low efficiency. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a calibration component, calibration method, test method and test system for a multi-port waveguide antenna test system, so as to alleviate the technical problems of poor calibration accuracy and low efficiency in traditional multi-port waveguide antenna testing.

[0007] In a first aspect, embodiments of the present invention provide a calibration component for a multi-port waveguide antenna test system, comprising: a positioning structure and multiple standard units; The positioning structure is used to ensure accurate positioning of each calibration connection, so that the interface of the calibration component and the interface of the device under test are in the same position, thereby ensuring repeatable high-precision calibration. The plurality of standard units are used to provide different standard states, wherein the plurality of standard units include: a short-circuit unit, a load unit, an offset short-circuit unit, and an offset load unit; The load unit, the offset short-circuit unit, and the offset load unit have multiple waveguide ports identical to those of the device under test, which are used to directly connect to the waveguide conversion fixture of the multi-port waveguide antenna test system. The internal structure of the waveguide port of the load unit is an antenna, which is used to radiate the incident electromagnetic wave energy into free space to achieve impedance matching.

[0008] Furthermore, the positioning structure includes: a positioning pin and a positioning hole that cooperate with each other, or a limiting step.

[0009] Furthermore, the antenna includes one of the following: a horn antenna, a Vivaldi antenna, a helical antenna, and a log-periodic antenna.

[0010] Secondly, embodiments of the present invention also provide a calibration method for calibrating a multi-port waveguide antenna test system using a calibration device as described in any of the first aspects, comprising: By sequentially connecting the vector network analyzer, waveguide switch, waveguide conversion fixture, and the calibration component, a measurement link is obtained; A test channel is selected by the waveguide switch, and different standard units of the calibration component are connected to the test channel in sequence. The S-parameters of the test channel on the interface reference surface of the device under test are measured by the vector network analyzer until the measurement of all test channels is completed. The vector network analyzer calculates and saves the calibration error model from the system's original reference plane to the interface reference plane of the device under test based on the S-parameters of all test channels on the interface reference plane of the device under test.

[0011] Furthermore, the standard unit includes: a short-circuit unit, a load unit, an offset short-circuit unit, and an offset load unit.

[0012] Thirdly, embodiments of the present invention also provide a testing method for a multi-port waveguide antenna, comprising: The multi-port waveguide antenna test system is calibrated using the calibration method described in the second aspect to obtain a calibration error model. Replace the calibration component with the device under test (DUT), keeping the rest of the measurement link unchanged, and measure the original S-parameters of the DUT. The original S-parameters of the device under test (DUT) are mathematically corrected using the calibration error model to obtain the true S-parameters of the DUT on the interface reference surface.

[0013] Fourthly, embodiments of the present invention also provide a multi-port waveguide antenna test system for implementing the test method as described in the third aspect. The test system includes: a vector network analyzer, a waveguide switch, a waveguide conversion fixture, and a calibration component as described in any one of the first aspects.

[0014] In this embodiment of the invention, a calibration component for a multi-port waveguide antenna test system is provided, comprising: a positioning structure and multiple standard units; the positioning structure is used to ensure accurate positioning of each calibration connection, so that the interface of the calibration component is in the same position as the interface of the device under test, thereby ensuring repeatable high-precision calibration; the multiple standard units are used to provide different standard states, wherein the multiple standard units include: a short-circuit unit, a load unit, an offset short-circuit unit, and an offset load unit; wherein the load unit, the offset short-circuit unit, and the offset load unit have multiple waveguide ports identical to those of the device under test, for directly connecting to the waveguide conversion fixture of the multi-port waveguide antenna test system, and the internal structure of the waveguide port of the load unit is an antenna, used to radiate incident electromagnetic wave energy into free space to achieve impedance matching. As described above, the calibration component for a multi-port waveguide antenna test system of the present invention features a positioning structure that ensures repeatability of each connection, a prerequisite for high-precision calibration. The load unit, offset short-circuit unit, and offset load unit have multiple waveguide ports identical to those of the device under test (DUT), allowing for direct docking. The internal structure of the waveguide ports in the load unit is an antenna, radiating electromagnetic energy instead of internal absorption, fundamentally solving the problems of wideband matching, heat dissipation, and power capacity. This ensures the high precision and stability of the load standard itself. Furthermore, a reference plane can be established at the interface of the DUT, allowing direct testing of the calibration error model without the need for waveguide conversion fixtures. The simulated S-parameter file fundamentally eliminates the errors caused by inaccurate simulated S-parameter files of waveguide conversion fixtures, resulting in high accuracy. Furthermore, the calibration error model solved during each calibration already includes all time-varying characteristics (temperature drift, aging, clamping changes) of the entire test link (switches, cables, fixtures, etc.). Therefore, this invention can perform frequent calibrations as needed to address measurement errors caused by temperature drift and link loss. Calibration can be performed quickly by simply disconnecting the port of the device under test from the test link and connecting the calibration component via automated equipment or manually. This high efficiency alleviates the technical problems of poor calibration accuracy and low efficiency in traditional multi-port waveguide antenna testing. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 A top view of a short-circuit unit provided in an embodiment of the present invention; Figure 2 A perspective view of a short-circuit unit provided in an embodiment of the present invention; Figure 3 A side view of a short-circuit unit provided in an embodiment of the present invention; Figure 4 A top view of the load unit provided in an embodiment of the present invention; Figure 5 A perspective view of the load unit provided in an embodiment of the present invention; Figure 6 A side view of a load unit provided in an embodiment of the present invention; Figure 7 This is a top view of the offset short-circuit unit provided in an embodiment of the present invention; Figure 8 A perspective view of the offset short-circuit unit provided in an embodiment of the present invention; Figure 9 This is a side view of the offset short-circuit unit provided in an embodiment of the present invention; Figure 10 A top view of the offset load unit provided in an embodiment of the present invention; Figure 11 A perspective view of the offset load unit provided in an embodiment of the present invention; Figure 12 A side view of the offset load unit provided in an embodiment of the present invention; Figure 13 A flowchart of a calibration method for calibrating a multi-port waveguide antenna test system using a calibration device provided in an embodiment of the present invention; Figure 14 A schematic diagram of the measurement link provided in an embodiment of the present invention; Figure 15 A flowchart illustrating a testing method for a multi-port waveguide antenna provided in an embodiment of the present invention. Detailed Implementation

[0017] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Traditional multi-port waveguide antenna testing suffers from poor calibration accuracy and low efficiency.

[0019] Based on this, in the calibration component of the multi-port waveguide antenna test system of the present invention, the positioning structure ensures the repeatability of each connection, which is a prerequisite for high-precision calibration. The load unit, offset short-circuit unit, and offset load unit have multiple waveguide ports identical to the device under test (DUT), which can be directly connected. The internal structure of the waveguide port of the load unit is an antenna, which can radiate electromagnetic wave energy instead of absorbing it internally, fundamentally solving the problems of wideband matching, heat dissipation, and power capacity, and ensuring the high precision and stability of the load standard itself. In addition, a reference plane can be established at the interface of the DUT, and the calibration error mode can be directly measured and obtained on this reference plane. This invention eliminates the need for simulation S-parameter files of waveguide conversion fixtures, fundamentally eliminating errors caused by inaccurate simulation S-parameter files. It offers high accuracy. Furthermore, the calibration error model solved during each calibration already includes all time-varying characteristics (temperature drift, aging, clamping changes) of the entire test link (switch, cable, fixture, etc.). Therefore, this invention can perform frequent calibrations as needed to address measurement errors caused by temperature drift and link loss. Calibration can be performed quickly and efficiently simply by disconnecting the port of the device under test from the test link and connecting the calibration component via automated equipment or manually.

[0020] To facilitate understanding of this embodiment, a calibration component for a multi-port waveguide antenna testing system disclosed in this embodiment of the invention will first be described in detail.

[0021] Example 1: According to an embodiment of the present invention, a calibration component for a multi-port waveguide antenna test system is provided. The calibration component includes: a positioning structure and multiple standard units; The positioning structure is used to ensure accurate positioning of each calibration connection, so that the interface of the calibration component is in the same position as the interface of the component under test, thereby ensuring repeatable high-precision calibration. Multiple standard units are used to provide different standard states, including: Short unit, Load unit, Offset Short unit, and Offset Load unit. Among them, the load unit, the offset short-circuit unit, and the offset load unit have multiple waveguide ports identical to the device under test, which are used to directly connect to the waveguide conversion fixture of the multi-port waveguide antenna test system. The internal structure of the waveguide port of the load unit is an antenna, which is used to radiate the incident electromagnetic wave energy into free space to achieve impedance matching.

[0022] Specifically, the calibration component of this invention is used to calibrate a multi-port waveguide antenna test system. The aforementioned interface can be understood as a radio frequency interface. The aforementioned load unit, offset short-circuit unit, and offset load unit have multiple waveguide ports identical to those of the device under test (DUT), meaning the number, layout, size, and interface type of the ports are all the same. The aforementioned offset short-circuit unit and offset load unit are implemented by introducing a transmission line of known length (e.g., whose electrical length is one-quarter of the waveguide wavelength). Figure 1 A top view of the short-circuit element is shown, where S stands for Short. The short-circuit element can be implemented as a solid metal or surface metallized. Figure 1 The two circles indicate the positioning holes (the same applies below). Figure 2 The image shows a three-dimensional perspective view of the short-circuit cell. Figure 3 The image shows a side view of the short-circuit unit. Figure 4 The diagram shows a top view of the load cell, where L stands for Load. The eight rectangles on the diagram represent eight waveguide ports, which are the same as the waveguide ports of the device under test (DUT) (hereinafter the same). Figure 5 The image shows a perspective view of the load unit. In this embodiment, the load design uses a horn antenna. Figure 6 The image shows a side view of the load cell. Figure 7 The diagram shows a top view of an offset short-circuit unit. An offset short-circuit unit is typically a short circuit plus a waveguide transmission line of a preset length. In this embodiment, it is a short circuit plus a waveguide transmission line of one-quarter of the waveguide wavelength (S+1 / 4). Figure 8 The image shows a three-dimensional perspective view of the offset short-circuit unit. Figure 9 The image shows a side view of the offset short-circuit unit. Figure 10 The diagram shows a top view of an offset load unit. An offset load unit is typically a load plus a waveguide transmission line of a preset length. In this embodiment, it is a load plus a waveguide transmission line of one-quarter of the waveguide wavelength (L+1 / 4). Figure 11 The image shows a three-dimensional perspective view of the offset load cell. Figure 12 The image shows a side view of the offset load unit. In this embodiment, the load design uses a horn antenna.

[0023] In this embodiment of the invention, a calibration component for a multi-port waveguide antenna test system is provided, comprising: a positioning structure and multiple standard units; the positioning structure is used to ensure accurate positioning for each calibration connection, so that the interface of the calibration component is at the same position as the interface of the device under test (DUT), that is, when the calibration component is in the connected state, the physical position of its interface is the same as the physical position of the interface of the DUT when it is in the connected state, so that the reference plane defined by the interface of the calibration component always coincides with the physical plane of the interface of the DUT, thereby ensuring repeatable high-precision calibration; the multiple standard units are used to provide different standard states, wherein the multiple standard units include: a short-circuit unit, a load unit, an offset short-circuit unit, and an offset load unit; wherein the load unit, the offset short-circuit unit, and the offset load unit have multiple waveguide ports identical to those of the DUT, for directly connecting to the waveguide conversion fixture of the multi-port waveguide antenna test system, and the internal structure of the waveguide port of the load unit is an antenna, used to radiate incident electromagnetic wave energy into free space to achieve impedance matching. As described above, in the calibration component of the multi-port waveguide antenna test system of the present invention, the positioning structure ensures the repeatability of each connection, which is a prerequisite for high-precision calibration. The load unit, offset short-circuit unit, and offset load unit have multiple waveguide ports identical to the device under test (DUT), allowing direct docking. The internal structure of the waveguide port of the load unit is an antenna, which radiates electromagnetic wave energy instead of absorbing it internally, fundamentally solving the problems of wideband matching, heat dissipation, and power capacity, and ensuring the high precision and stability of the load standard itself. In addition, by establishing the reference plane directly at the interface of the DUT, the calibration error model can be directly tested and obtained on this reference plane without the need for waveguide converters. The simulation S-parameter file for the tooling change fundamentally eliminates the errors caused by the inaccuracy of the simulation S-parameter file for the waveguide conversion tooling. In addition, the calibration error model solved during each calibration already includes all time-varying characteristics (temperature drift, aging, clamping changes) of the entire test link (switches, cables, tooling, etc.). Therefore, this invention can perform frequent calibrations as needed to address measurement errors caused by temperature drift and link loss. Simply disconnect the port of the device under test from the test link, and calibration can be performed quickly by connecting the calibration component through automated equipment or manually. This is highly efficient and alleviates the technical problems of poor calibration accuracy and low efficiency in traditional multi-port waveguide antenna testing.

[0024] The above provides a brief overview of the calibration component for a multi-port waveguide antenna test system of the present invention. The specific details involved are described below.

[0025] In an optional embodiment of the present invention, the positioning structure includes: a positioning pin and a positioning hole that cooperate with each other, or a limiting step.

[0026] In an optional embodiment of the present invention, the small antenna radiator includes one of the following: a small horn antenna, a Vivaldi antenna, a helical antenna, and a log-periodic antenna.

[0027] Example 2: According to an embodiment of the present invention, a calibration method for calibrating a multi-port waveguide antenna test system using the calibration component of Embodiment 1 is provided, with reference to... Figure 13 It includes the following steps: Step S1302: Connect the vector network analyzer, waveguide switch, waveguide conversion fixture and calibration component in sequence to obtain the measurement link; Step S1304: Select a test channel by using a waveguide switch, connect different standard units of the calibration component to the test channel in sequence, and measure the S-parameters of the test channel on the interface reference surface of the test component using a vector network analyzer until the measurement of all test channels is completed. In step S1306, the vector network analyzer calculates and saves the calibration error model between the original system reference plane and the actual interface reference plane of the device under test based on the S-parameters of all test channels on the interface reference plane of the device under test.

[0028] Specifically, let's take an 8-port waveguide antenna as an example for explanation. (Refer to...) Figure 14 Connect the measurement link, and then connect the vector network analyzer, the 1-to-8 waveguide switch 100, the waveguide conversion fixture 200, and the calibration kit 300 in sequence. On the VNA (vector network analyzer), select the calibration type, and use the waveguide switch 100 to sequentially select each test channel (i.e., port channel). For each port channel, connect the four standard units of the calibration kit in sequence, so that the port presents different standard states in sequence. Measure the S-parameters of the port on the interface reference surface of the device under test through the VNA. After completing the measurement of all standards for the port, switch to the next port and repeat the above operation. After completing the calibration measurement of all ports, the VNA calculates and saves the calibration error model, that is, the error between the original system reference surface and the interface reference surface of the device under test.

[0029] In an optional embodiment of the present invention, the standard unit includes: a short-circuit unit, a load unit, an offset short-circuit unit, and an offset load unit.

[0030] The calibration method of the present invention can directly and stably establish the test reference surface at the actual physical interface of the test piece, and is suitable for batch testing on the production line.

[0031] Example 3: According to an embodiment of the present invention, a test method for a multi-port waveguide antenna is provided, with reference to... Figure 15 It includes the following steps: Step S152: The multi-port waveguide antenna test system is calibrated using the calibration method of Example 2 to obtain the calibration error model; Step S154: Replace the calibration component with the device under test, keeping the other parts of the measurement link unchanged, and measure the original S-parameters of the device under test; Step S156: The original S-parameters of the test device are mathematically corrected using the calibration error model to obtain the true S-parameters of the test device on the interface reference surface of the test device.

[0032] Specifically, during testing, the standard component is replaced with the component under test (DUT), while keeping other connections unchanged, and the test can be performed to obtain the original S-parameters of the DUT (i.e., the S-parameters of the DUT on the original reference plane of the system). After the test is completed, the S-parameters of the DUT on the original reference plane of the system are mathematically corrected according to the calibration error model obtained from the calibration, so as to obtain the true S-parameters of the DUT on the interface reference plane of the DUT.

[0033] Example 4: According to an embodiment of the present invention, a multi-port waveguide antenna test system is provided for implementing the test method as described in Embodiment 3. The test system includes: a vector network analyzer, a waveguide switch, a waveguide conversion fixture, and a calibration component.

[0034] Compared with existing technologies, this solution has the following advantages: Firstly, in the design of the calibration component, the load element is designed using a small antenna radiator, and its technical effects are described in detail here. The design goal of the waveguide load is to reduce port reflection and achieve a low voltage standing wave ratio (VSWR). One existing implementation involves placing a gradient-shaped absorber inside the load sheet; however, this significantly increases the physical size of the load when the bandwidth is wide. Another existing implementation uses a precisely calculated resonant absorption structure, but this is typically only suitable for point frequencies or narrow bands. Designing the waveguide calibration load as a small antenna changes the core design concept from "absorbing energy" to "radiating energy." This implementation has excellent ultra-wideband potential. Theoretically, electrically small antennas can achieve matching with a size much smaller than the wavelength. In other words, with proper antenna design, good matching characteristics (low reflection, low VSWR) can be maintained over an extremely wide bandwidth without requiring a physical size proportional to the wavelength, making it very suitable for waveguide antenna test components with strict space constraints. Furthermore, the antenna-type load radiates energy to the external space during use, rather than converting it into heat internally, thus solving the heat dissipation problem. This allows for higher power capacity and avoids performance drift caused by temperature changes (impedance changes with temperature). In summary, the design of this calibration component reduces the error of the load standard itself, improves the accuracy and precision of broadband calibration, and further lays the foundation for measurement accuracy. In the load unit shown in the attached figure, the port reflection coefficient is less than -25dB.

[0035] Secondly, existing technologies place the initial reference plane at the standard waveguide interface of the test instrument output or switch matrix output, and then move the reference plane from the initial reference plane to the DUT interface by combining the simulation S-parameter file of the conversion fixture with baseline correction. This solution, however, establishes the reference plane directly at the DUT's test interface. The calibration error model can be directly obtained from this reference plane without using the simulation S-parameter file of the conversion fixture, fundamentally eliminating the errors caused by the inaccuracy of the simulation S-parameter file. Furthermore, the error term solved during each calibration already includes all time-varying characteristics (temperature drift, aging, clamping variations) of the entire test link (switches, cables, fixtures, etc.). Therefore, this solution can perform frequent calibrations as needed to address measurement errors caused by temperature drift and link loss. Calibration can be quickly performed by simply disconnecting the DUT port from the test link and connecting the calibration component via automated equipment or manually.

[0036] The calibration process in this solution can be standardized and automated, eliminating the need for complex and inaccurate simulations or offline calibrations of non-standard tooling, as well as the need to establish and maintain a large tooling S-parameter library. This reduces the technical requirements for operators, minimizes human error, improves efficiency, and makes the production line testing cycle controllable. This solution has shown good results for the production line testing of eight-port ridge waveguide antennas for automotive radar antennas. Of course, the components under test are not limited to this; this solution is also applicable to testing scenarios for other multi-port waveguide antennas.

[0037] The inventive points of this invention are as follows: Design of a dedicated integrated calibration kit for non-standard multi-port waveguides Technical problem to be solved: Existing technologies lack readily available calibration components suitable for non-standard, multi-port, small-size waveguide interfaces, making it impossible to directly establish a calibration reference surface on the DUT interface.

[0038] Technical means: A special calibration component integrating multiple standard units was designed.

[0039] Its innovation lies in: Precision positioning structure: Includes positioning pins / holes or limiting steps to ensure repeatability of each connection, which is a prerequisite for high-precision calibration.

[0040] Port matching design: Standard units such as loads have the exact same number of ports, layout and interface type as the DUT, ensuring direct docking and physically establishing the reference plane at the DUT interface.

[0041] Innovative load implementation: The load unit is designed as a miniaturized antenna radiating structure (such as a horn antenna), which radiates energy instead of absorbing it internally. This fundamentally solves the problems of wideband matching, heat dissipation and power capacity, and ensures the high precision and stability of the load standard itself.

[0042] Invention Point 2: Error Model Establishment Method Based on Direct Calibration Technical problem to be solved: Traditional methods rely on simulation and offline calibration to convert the S-parameters of the tooling, which has large errors and cannot cope with the time-varying drift of the system.

[0043] Technical approach: Using the aforementioned calibration components, the calibration process is performed directly at the actual physical interface of the DUT. By sequentially connecting each test port to four standard states—short circuit, load, offset short circuit, and offset load—and measuring the S-parameters, the Vector Network Analyzer (VNA) can directly calculate the complete calibration error model from the system's original reference plane to the DUT interface. This method eliminates the need for inaccurate simulation S-parameter files; the calibration error model directly includes all time-varying characteristics of the test link.

[0044] Invention Point 3: Online, repeatable, and automated high-frequency calibration capability Technical problems to be solved: Traditional calibration methods are complex and time-consuming, and cannot cope with factors such as temperature drift and aging, resulting in low production efficiency.

[0045] Technical means: Due to the ingenious design of the calibration components, their quick and reliable connection, and the fact that the calibration process can be automatically controlled by VNA, frequent calibration is possible. The production line can quickly disconnect the DUT, connect the calibration components, and perform fully automatic calibration as needed (such as during timed or temperature changes), thereby continuously correcting errors introduced by time-varying factors such as temperature drift and aging, ensuring the consistency and reliability of long-term measurements.

[0046] Furthermore, in the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0047] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0048] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A calibration piece for a multi-port waveguide antenna test system, the calibration piece comprising: The calibration device comprises: a positioning structure and a plurality of standard units; the positioning structure is used to ensure accurate positioning of the calibration device each time, so that the interface of the calibration device is in the same position as the interface of the measured device, thereby ensuring repeatable high-precision calibration; the plurality of standard units are used to provide different standard states, wherein the plurality of standard units comprise a short-circuit unit, a load unit, an offset short-circuit unit and an offset load unit; the load unit, the offset short-circuit unit and the offset load unit have a plurality of waveguide ports which are the same as those of the measured device, and are used to directly connect to a waveguide conversion tool of a multi-port waveguide antenna test system; and the waveguide ports of the load unit have an internal structure of an antenna, and are used to radiate incident electromagnetic wave energy to free space, thereby achieving impedance matching.

2. The calibration piece of claim 1, wherein, The positioning structure comprises a positioning pin and a positioning hole which cooperate with each other, or a limiting step.

3. The calibration piece of claim 1, wherein, The antenna comprises one of a horn antenna, a Vivaldi antenna, a spiral antenna and a log-periodic antenna.

4. A calibration method of calibrating a multi-port waveguide antenna test system using the calibration piece according to any one of claims 1 to 3, characterized in that, The calibration method comprises: connecting a vector network analyzer, a waveguide switch, a waveguide conversion tool and the calibration device in sequence to obtain a measurement link; selecting one test channel through the waveguide switch, connecting different standard units of the calibration device to the test channel in sequence, and measuring S parameters of the test channel on a reference surface of a measured device interface through the vector network analyzer until the measurement of all test channels is completed; the vector network analyzer calculates and saves a calibration error model from a system original reference surface to the reference surface of the measured device interface according to the S parameters of all test channels on the reference surface of the measured device interface.

5. The method of calibration of claim 4, wherein, The standard units comprise a short-circuit unit, a load unit, an offset short-circuit unit and an offset load unit.

6. A method of testing a multi-port waveguide antenna, the method comprising: The test method comprises: calibrating a multi-port waveguide antenna test system by using the calibration method of claim 4 or 5 to obtain a calibration error model; replacing the calibration device with a measured device while keeping other parts of the measurement link unchanged to measure original S parameters of the measured device; mathematically correcting the original S parameters of the measured device by using the calibration error model to obtain real S parameters of the measured device on a reference surface of the measured device interface.

7. A multi-port waveguide antenna test system, characterized by, The test system used to implement the test method of claim 6 comprises a vector network analyzer, a waveguide switch, a waveguide conversion tool and the calibration device of any one of claims 1 to 3.

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