Automatic measuring device for resonant cavity characteristic impedance

Abstract

The utility model discloses a kind of resonant cavity characteristic impedance automatic measuring devices, including the test platform for positioning measured resonant cavity, traction line, executing device, control processing equipment and measuring instrument, traction line is passed by the inside of measured resonant cavity and its one end hangs counterweight, executing device is driven connection with the other end of traction line;While fixed on traction line perturbing object, perturbing object is in measured resonant cavity;Control processing equipment is used to control executing device traction traction line, so that perturbing object moves along the central axis of measured resonant cavity;Measuring instrument is used to detect the parameter of measured resonant cavity in the moving process of perturbing object and transmit data to control processing equipment, control processing equipment is used to process the data transmitted by measuring instrument and output the characteristic impedance of measured resonant cavity.The utility model can realize the full-process automation measurement of resonant cavity characteristic impedance, and greatly simplify test procedure, improve measurement efficiency and measurement accuracy.

Description

Technical Field

[0001] This utility model relates to the field of resonant cavity characteristic impedance measurement technology, and in particular to an automatic resonant cavity characteristic impedance measurement device. Background Technology

[0002] A klystron is a high-power vacuum electronic amplifier based on transit radiation. Due to its advantages such as high power, high gain, high stability, and low phase noise, klystrons are widely used in large scientific facilities, medical accelerators, radar, and industrial irradiation. In the design of a klystron, the characteristic impedance is one of the important parameters of the resonant cavity, which depends on the geometry and resonant frequency of the cavity and determines the gain and electronic efficiency of the klystron. Accurate measurement of the characteristic impedance of the klystron's resonant cavity is necessary during its manufacturing process.

[0003] Currently, the main method for measuring the characteristic impedance of resonant cavities is the perturbation method. According to electromagnetic perturbation theory, when the size, shape, and internal materials of a resonant cavity undergo subtle changes, its characteristic impedance can be indirectly measured through changes in its resonant frequency. However, measuring the characteristic impedance by changing the shape of the resonant cavity during testing is clearly impractical. Therefore, methods that generate perturbations by introducing perturbing objects mainly take the following two forms: The first method involves introducing a small metal perturbation ball at the center axis of the drift tube. However, the ball needs to be moved continuously during the measurement process, which is currently done manually. This method requires manually moving the ball, adjusting the measuring equipment, and manually observing the experimental data. It is inconvenient and requires multiple people to work together, resulting in high manpower requirements and long testing time.

[0004] The second method involves introducing a very thin cylindrical perturbation into the resonant cavity gap. However, the thin cylindrical perturbation is difficult to manufacture and is easily damaged. It also requires constant replacement of the cylindrical perturbation, making the experimental steps cumbersome and inefficient.

[0005] With the continuous improvement of testing technology, simplifying testing procedures and increasing testing efficiency have become inevitable trends in the high-efficiency production of klystrons. Therefore, there is an urgent need for an automatic measurement device for the characteristic impedance of resonant cavities to achieve automated measurement of resonant cavity performance. Utility Model Content

[0006] The problem to be solved by this utility model is to provide an automatic measurement device for the characteristic impedance of a resonant cavity, so as to overcome the shortcomings of existing resonant cavity characteristic impedance measurement, such as high manpower requirements, long time consumption, cumbersome steps and low efficiency.

[0007] The technical solution adopted by this utility model to solve its technical problem is: an automatic measurement device for the characteristic impedance of a resonant cavity, comprising: Test platform used to locate the resonant cavity under test; A traction wire passes through the interior of the resonant cavity under test and a counterweight is suspended at one end of the traction wire. A perturbation object is fixed on the traction wire and is located inside the resonant cavity under test. An actuator is mounted on the test platform and drivenly connected to the other end of the traction line; A control processing device, which is communicatively connected to the actuator, is used to control the actuator to pull the traction line, so that the perturbation object moves along the central axis of the resonant cavity under test. The measuring instrument is communicatively connected to the control and processing device, and is used to detect the parameters of the resonant cavity under test during the movement of the perturbation object and transmit the data to the control and processing device. The control and processing device is used to process the data transmitted by the measuring instrument and output the characteristic impedance of the resonant cavity under test.

[0008] As a further improvement of this utility model, the resonant cavity under test is placed on the test platform in a horizontal direction, and the traction wire passes through the interior of the resonant cavity under test in a horizontal direction.

[0009] As a further improvement of this utility model, a traction wheel and a reversing wheel are rotatably mounted on the test platform. The traction wheel and the reversing wheel are respectively arranged on both sides of the resonant cavity under test. One end of the traction line passes around the reversing wheel and is connected to the counterweight, while the counterweight is in a free suspension state. The other end of the traction line is connected to the traction wheel.

[0010] As a further improvement of this utility model, the actuator is a motor connected to the traction wheel, and the actuator can drive the traction wheel to rotate according to the step length and number of steps set by the control processing equipment.

[0011] As a further improvement of this utility model, the test platform is provided with a fixture, the resonant cavity under test is fixed on the fixture, and the fixture is provided with an adjusting screw, which is used to finely adjust the position of the resonant cavity under test so that the traction wire coincides with the central axis of the resonant cavity under test.

[0012] As a further improvement of this utility model, the control processing device includes an instruction coordination unit and a data processing unit; the instruction coordination unit is configured to send drive control instructions to the execution device and measurement control instructions to the measuring instrument; the data processing unit is configured to acquire parameter measurement data of the resonant cavity under test from the measuring instrument and process it, thereby outputting the characteristic impedance of the resonant cavity under test.

[0013] As a further improvement of this utility model, the measuring instrument is a vector network analyzer, which is connected to the resonant cavity under test via a coaxial cable.

[0014] As a further improvement of this utility model, the control processing device is a computer, which is connected to the measuring instrument via a general interface bus and to the execution device via a serial port.

[0015] As a further improvement of this utility model, the perturbation object is a metal sphere.

[0016] As a further improvement of this utility model, the automatic measurement device for resonant cavity characteristic impedance also includes a display for displaying the measured value of the characteristic impedance of the resonant cavity under test.

[0017] The beneficial effects of this utility model are as follows: This utility model provides an automatic measurement device for the characteristic impedance of a resonant cavity. By integrating a test platform, a traction line with a counterweight and a perturbation object, an execution device, a control processing device, and a measuring instrument, it realizes the fully automated measurement of the characteristic impedance of the resonant cavity. It eliminates the need for manual movement of the perturbation object, manual adjustment of the equipment, or manual recording of data, thus solving the problems of the traditional manual small ball perturbation method, which requires multiple people, has high manpower requirements, and is time-consuming. It greatly simplifies the test steps and improves the measurement efficiency. At the same time, the control processing device coordinates the execution device and the measuring instrument in a unified manner, avoiding random errors caused by manual operation, improving the measurement accuracy, and can directly output the measurement results. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of the automatic measurement device for the characteristic impedance of the resonant cavity of this utility model; Figure 2 This is a cross-sectional view of the resonant cavity under test, the traction wire, and the perturbation object of this utility model. Figure 3 This is a system block diagram of the automatic measurement device for the characteristic impedance of the resonant cavity of this utility model.

[0020] Referring to the accompanying drawings, the following explanations are provided: 1. The resonant cavity under test; 2. The test platform; 3. The traction line; 4. The counterweight; 5. The perturbation object; 6. The actuator; 7. The control and processing equipment; 8. The measuring instrument; 9. The traction wheel; 10. The reversing wheel; 11. The display; 12. The metal probe; A. The measurement starting point; B. The measurement ending point. Detailed Implementation

[0021] The present application will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0022] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0024] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0025] Additionally, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that practice can be carried out without these specific details.

[0026] The technical solutions provided by the various embodiments of this application are described below with reference to the accompanying drawings.

[0027] See Figure 1 and Figure 3 This utility model provides an automatic measuring device for the characteristic impedance of a resonant cavity, used to test the characteristic impedance of the resonant cavity 1 under test. It includes a test platform 2, a traction line 3, a counterweight 4, a perturbation object 5, an actuator 6, a control and processing device 7, and a measuring instrument 8.

[0028] The test platform 2 is used to place and position the resonant cavity 1 under test. The actuator 6, control processing equipment 7, and measuring instruments 8 are all mounted on the test platform 2. The traction wire 3 passes through the interior of the resonant cavity 1 under test. The counterweight 4 is suspended at one end of the traction wire 3, providing continuous tension through its own weight to keep the traction wire 3 taut at all times. The other end of the traction wire 3 is driven and connected to the actuator 6. The perturbation object 5 is fixed in the middle of the traction wire 3 and is located inside the resonant cavity 1 under test.

[0029] Furthermore, the control processing device 7 is communicatively connected to the actuator 6 and is used to control the actuator 6 to pull the traction line 3, causing the perturbation object 5 to move along the central axis of the resonant cavity 1 under test. The measuring instrument 8 is communicatively connected to the control processing device 7 and is used to detect the parameters of the resonant cavity 1 under test during the movement of the perturbation object 5 and transmit the data to the control processing device 7. The control processing device 7 processes the data transmitted by the measuring instrument 8 and outputs the characteristic impedance of the resonant cavity 1 under test.

[0030] This invention achieves fully automated measurement of the characteristic impedance of a resonant cavity by integrating a "test platform 2, a traction line 3 with a counterweight 4 and a perturbation object 5, an execution device 6, a control and processing device 7, and a measuring instrument 8". It eliminates the need for manual movement of the perturbation object 5, manual adjustment of the equipment, or manual recording of data, thus solving the problems of the traditional manual ball perturbation method, which requires multiple people, has high manpower requirements, and is time-consuming. This significantly simplifies the testing steps and improves measurement efficiency. At the same time, the control and processing device 7 coordinates the execution device 6 and the measuring instrument 8, avoiding random errors caused by manual operation, improving measurement accuracy, and allowing direct output of measurement results.

[0031] In this invention, the resonant cavity 1 under test is placed horizontally on the test platform 2, meaning the central axis of the resonant cavity 1 extends horizontally. The middle section of the traction wire 3 passes horizontally through the interior of the resonant cavity 1. The perturbation object 5 is fixed to the horizontal section of the traction wire 3 and is located inside the resonant cavity 1. By placing the resonant cavity 1 horizontally and having the traction wire 3 pass horizontally through the interior of the resonant cavity 1, the displacement of the perturbation object 4 caused by the tilt of the resonant cavity 1 or the non-horizontal nature of the traction wire 3 can be avoided. Compared to a non-horizontal arrangement (such as a vertical arrangement which is easily affected by gravity, causing the traction wire to sag or shift), a horizontal arrangement ensures that the perturbation object always moves along the central axis of the resonant cavity 1, reducing measurement errors introduced by trajectory deviation, further ensuring the alignment accuracy of the perturbation object 5 with the central axis of the resonant cavity 1, and providing a stable displacement reference for characteristic impedance calculation.

[0032] like Figure 1 As shown, a traction wheel 9 and a reversing wheel 10 are rotatably mounted on the test platform 2. The traction wheel 9 and the reversing wheel 10 are respectively arranged on the left and right sides of the resonant cavity 1 under test. At the same time, the reversing wheel 10 is located at the edge of the test platform 2. One end of the traction line 3 passes around the reversing wheel 10 and is connected to the counterweight 4, while the counterweight 4 is in a free suspension state. The other end of the traction line 3 is fixedly connected to the traction wheel 9, wherein the traction wheel 9 is provided with a winding groove.

[0033] In this embodiment, the actuator 6 is a motor, specifically a stepper motor, whose motor shaft is fixedly connected to the traction wheel 9. The actuator 6 can drive the traction wheel 9 to rotate according to the step length and number of steps set by the control processing device 7, so as to wind the traction line 3 into the winding groove. At the same time, the traction line 3 drives the micro-perturbation object 5 to move along the central axis of the resonant cavity 1 under test, which can realize the precise quantitative displacement of the micro-perturbation object. Compared with traditional manual movement, the stepping control of the motor can strictly adjust the movement distance of the micro-perturbation object according to the preset parameters, reduce the distance error caused by manual movement, and improve the test accuracy.

[0034] Furthermore, in order to ensure that the horizontal section in the middle of the traction line 3 coincides with the central axis of the resonant cavity 1 under test, so that the perturbation object 5 can move along the central axis of the resonant cavity 1 under test, the present invention also provides a clamp (not shown in the figure) on the test platform 2. The resonant cavity 1 under test is fixed on the clamp, and the clamp is provided with an adjusting screw. The adjusting screw is used to fine adjust the position of the resonant cavity 1 under test so that the traction line 3 coincides with the central axis of the resonant cavity 1 under test.

[0035] It should be noted that the fixture used to fix the resonant cavity 1 under test and the fine-tuning screw used to fine-tune the position of the resonant cavity 1 under test to ensure that the perturbation object 5 is on the central axis of the resonant cavity 1 under test are both conventional and existing technologies. The core function of the fixture is to stably fix the resonant cavity 1 under test and prevent cavity displacement during measurement; the core function of the fine-tuning screw is to achieve precise calibration of the cavity position through minute adjustments. The design concepts and applications of both are already common in various precision component measuring devices; therefore, the fixture and fine-tuning screw are not considered improvements in this application.

[0036] Preferably, the perturbation object 5 is a metal sphere.

[0037] In addition, the automatic measurement device for characteristic impedance of resonant cavity also includes a display 11 for displaying the measured value of characteristic impedance of the resonant cavity 1 under test.

[0038] See Figure 3 In this embodiment, the control processing device 7 is specifically a computer, which is connected to the measuring instrument 8 via a General Purpose Interface Bus (GPIB) data line and to the execution device 6 via a serial port. The measuring instrument 8 is specifically a vector network analyzer, which is connected to the resonant cavity 1 under test via a coaxial cable. Figure 2 As shown, a metal probe 12 is connected to the end of the coaxial cable. The metal probe 12 extends into the resonant cavity 1 under test and is used to measure the S11 parameter of the resonant cavity 1 under test.

[0039] Among them, the S11 parameter reflects "the proportion of the signal that is reflected back to port 1 by the resonant cavity 1 after being emitted from port 1 of the vector network analyzer". The frequency point corresponding to its minimum value is the resonant frequency of the resonant cavity 1 under test. By measuring the S11 parameter at different positions of the perturbation object 5, the angular frequency ω corresponding to the current position and the angular frequency ω0 corresponding to the measurement starting point A can be obtained, and then the relative frequency deviation σ can be calculated. Finally, the characteristic impedance can be obtained by substituting it into the formula.

[0040] The control processing device 7 includes an instruction coordination unit and a data processing unit.

[0041] The command coordination unit is configured to send drive control commands to the execution device 6 to control the step length and number of steps of the stepper motor; and simultaneously send measurement control commands to the measuring instrument 8 to set measurement parameters such as frequency range and number of measurement points.

[0042] The data processing unit is configured to: acquire S11 parameter measurement data of the resonant cavity under test from the vector network analyzer; determine the resonant frequency at different displacements based on the S11 parameters; calculate the relative frequency deviation σ; and, combining the displacement element dz and radius a of the perturbation object 5, calculate the characteristic impedance R / Q of the resonant cavity under test 1 using the characteristic impedance formula. The characteristic impedance formula is:

[0043] Where c is the speed of light, in units of 2.998 × 10⁸ m / s; a is the radius of the perturbation object, in units of m; ω is the angular frequency corresponding to the minimum point of S11 in each measurement; ω₀ is the angular frequency corresponding to the minimum point of S11 measured from the measurement starting point A; σ is the relative frequency offset; To integrate the square root of the relative frequency offset σ along the axis of the resonant cavity under test.

[0044] The measurement process of this novel automatic resonant cavity characteristic impedance measuring device is as follows: Points A and B are set inside the resonant cavity 1 under test, serving as the starting and ending points of the measurement, respectively. Before automatic measurement, the perturbation object 5 should be moved to the starting point A. The measurement ends when the perturbation object 5 moves to the ending point B. The number of motor steps is set to the ratio of the length of the resonant cavity 1 under test to the step length.

[0045] First, the parameters are configured and acquired in the automatic measurement device for characteristic impedance of the resonant cavity. The resonant cavity under test 1 is a 2-gap resonant cavity. The vector network analyzer used is an Agilent E8363B. The command coordination unit is set to the vector network analyzer frequency of 1.5GHz-3.5GHz, the number of measurement points of 3000, the motor step length of 0.5mm, and the number of steps of 110. The material of the perturbation object 5 is copper, the radius is 1mm, and the weight of the object is 1kg.

[0046] Secondly, the control processing device 7 sends drive control commands to the execution device 6 through the command coordination unit, and at the same time sends measurement control commands to the measuring instrument 8.

[0047] After the test begins, the motor pulls the perturbation object 5 to move. At the measurement starting point A, the vector network analyzer automatically measures the S11 parameter, automatically finds the frequency point corresponding to the minimum point of the S11 parameter and saves it. This data corresponds to ω0. The motor pulls the perturbation object 5 to move according to the set step length and number of steps. At the same time, the vector network analyzer automatically measures the S11 parameter, automatically finds the frequency point corresponding to the minimum point of the S11 parameter and saves it. This data corresponds to ω. This continues until the number of steps is reached. Next, the control processing device 7 automatically calculates the characteristic impedance of the measured resonant cavity 1 according to the characteristic impedance formula through the data processing unit, and outputs the test results to the display 11.

[0048] This invention relates to the measurement of characteristic impedance of a resonant cavity based on electromagnetic perturbation theory. The position of the perturbation object 5 directly affects the uniformity and accuracy of the electromagnetic perturbation. If the perturbation object 5 deviates from the central axis, it will cause local electromagnetic environment distortion, resulting in deviation of the measured value of the S11 parameter, and thus causing errors in the characteristic impedance calculation result. The fixed measurement starting point A and measurement ending point B, along with the precise number of steps, can ensure that the perturbation object 5 covers the entire length of the resonant cavity 1 under test, obtain complete frequency offset data, and ensure the integrity of the measurement.

[0049] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An automatic measurement device for the characteristic impedance of a resonant cavity, characterized in that, include: Test platform (2) for locating the resonant cavity under test (1); A traction wire (3) passes through the inside of the resonant cavity (1) under test and a counterweight (4) is suspended at one end of the traction wire (3). Meanwhile, a perturbation object (5) is fixed on the traction wire (3) and the perturbation object (5) is located inside the resonant cavity (1) under test. An actuator (6) is mounted on the test platform (2) and driven to the other end of the traction line (3); A control processing device (7), which is communicatively connected to the execution device (6), is used to control the execution device (6) to pull the traction line (3) so that the perturbation object (5) moves along the central axis of the resonant cavity under test (1); And a measuring instrument (8), which is connected to the control processing device (7) for detecting the parameters of the resonant cavity (1) under test during the movement of the perturbation object (5) and transmitting the data to the control processing device (7). The control processing device (7) is used to process the data transmitted by the measuring instrument (8) and output the characteristic impedance of the resonant cavity (1) under test.

2. The automatic measurement device for characteristic impedance of a resonant cavity according to claim 1, characterized in that, The resonant cavity under test (1) is placed on the test platform (2) in a horizontal direction, and the traction wire (3) passes through the interior of the resonant cavity under test (1) in a horizontal direction.

3. The automatic measurement device for characteristic impedance of a resonant cavity according to claim 2, characterized in that, The test platform (2) is rotatably mounted with a traction wheel (9) and a reversing wheel (10). The traction wheel (9) and the reversing wheel (10) are respectively arranged on both sides of the resonant cavity (1) under test. One end of the traction line (3) passes around the reversing wheel (10) and is connected to the counterweight (4), while the counterweight (4) is in a free suspension state. The other end of the traction line (3) is connected to the traction wheel (9).

4. The automatic measurement device for characteristic impedance of a resonant cavity according to claim 3, characterized in that, The actuator (6) is a motor connected to the traction wheel (9). The actuator (6) can drive the traction wheel (9) to rotate according to the step length and number of steps set by the control processing device (7).

5. The automatic measurement device for characteristic impedance of a resonant cavity according to claim 1, characterized in that, The test platform (2) is provided with a fixture, the resonant cavity (1) under test is fixed on the fixture, and the fixture is provided with an adjusting screw. The adjusting screw is used to fine adjust the position of the resonant cavity (1) under test so that the traction line (3) coincides with the central axis of the resonant cavity (1) under test.

6. The automatic measurement device for characteristic impedance of a resonant cavity according to claim 1, characterized in that, The control processing device (7) includes an instruction coordination unit and a data processing unit; the instruction coordination unit is configured to send a drive control instruction to the execution device (6) and a measurement control instruction to the measuring instrument (8); the data processing unit is configured to obtain the parameter measurement data of the resonant cavity (1) under test from the measuring instrument (8) and process it, and then output the characteristic impedance of the resonant cavity (1) under test.

7. The automatic measurement device for characteristic impedance of a resonant cavity according to claim 1, characterized in that, The measuring instrument (8) is a vector network analyzer, which is connected to the resonant cavity (1) under test via a coaxial cable.

8. The automatic measurement device for characteristic impedance of a resonant cavity according to claim 1, characterized in that, The control processing device (7) is a computer, which is connected to the measuring instrument (8) via a general interface bus and to the actuator (6) via a serial port.

9. The automatic measurement device for characteristic impedance of a resonant cavity according to claim 1, characterized in that, The perturbation object (5) is a metal sphere.

10. The automatic measurement device for characteristic impedance of a resonant cavity according to claim 1, characterized in that, It also includes a display (11) for displaying the measured value of the characteristic impedance of the resonant cavity (1) under test.

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