Integrated rectangular resonant cavity structure and its frequency correction method

Abstract

The present invention provides an integrated rectangular resonant cavity structure and a frequency correction method thereof, and relates to the technical field of microwave vacuum devices. The structure comprises: a plurality of rectangular resonant cavities connected in series, each rectangular resonant cavity is a vacuum cavity, comprising a rectangular cavity, elastic diaphragms arranged on the upper and lower sides of the rectangular cavity, and a sealed cavity wall arranged on the outer side of the elastic diaphragm; wherein the rectangular cavity comprises cavity covers on the upper and lower sides and cavity walls on the left and right sides, each cavity cover is hollow and welded with a drift head, and a drift gap is left between two opposite drift heads for drifting the input electron beam; the elastic diaphragm electrically contacts the rectangular cavity, and a plurality of coupling windows are opened on the elastic diaphragm, and the center of each coupling window corresponds to the center of a drift gap; the sealed cavity wall is used to ensure the vacuum tightness of the rectangular resonant cavity. The present invention can be used for the high-frequency clustering section of a klystron.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave electric vacuum devices, and in particular to an integrated rectangular resonant cavity structure and a frequency correction method thereof. Background Art

[0002] The klystron is a microwave electric vacuum device that requires multiple reentrant resonant cavities to be connected in series as high-frequency clustering sections and output sections. Each resonant cavity needs to undergo cold measurement and frequency correction, as well as multiple brazing and welding processes to form a vacuum-sealed high-frequency section of the klystron. In each process, the resonant frequency of the resonant cavity must be consistent with the design value to ensure the overall electrical performance of the klystron. Although the design calculation can determine the structure and geometric dimensions of the resonant cavity, due to certain simulation calculation errors and processing tolerances, the resonant frequency of the resonant cavity obtained during the actual cold measurement of the machined parts will still deviate from its design value to a greater or lesser extent. Especially for high-frequency klystrons, the size of the resonant cavity is small and the frequency deviation will be greater. Therefore, during the initial cold measurement of the resonant cavity of the klystron and the cold measurement after welding, it is often necessary to correct the frequency of the resonant cavity. Regarding the correction of the frequency of the resonant cavity, in the cold measurement experiment of the resonant cavity, if the resonant frequency is found to be low after the cold measurement, the size of the drift gap can be increased, and if the frequency is high, the cavity height of the resonant cavity can be increased. Before the resonant cavity is brazed, the above correction process can be carried out by machining the part size through a processing machine to achieve the purpose of frequency correction. However, if the resonant cavity needs to be adjusted and corrected after brazing, the following methods are usually used: Figure 1 and Figure 2 The structure shown, Figure 1 The resonant cavity of the inductor tuning method is given. Figure 2 A resonant cavity with capacitance tuning is given.

[0003] For a resonant cavity with a higher operating frequency, the cavity size is small, and the installation of a bellows will increase the complexity of the cavity structure and welding processes. In this case, the bellows can be replaced with a 0.3 mm thick elastic diaphragm, as shown in Figure 3 The high-frequency cluster section structure of the X-band klystron shown is composed of an integrally processed rectangular resonant cavity cover, cavity wall, and a 0.3 mm elastic diaphragm cavity wall.

[0004] Whether using Figure 1 and Figure 2 The bellows in Figure 3 The elastic diaphragm in the resonant cavity is a part of the cavity wall. Both the bellows and the elastic diaphragm have two functions: the frequency can be adjusted by changing the geometric dimensions of the resonant cavity through elastic deformation, while maintaining the vacuum seal of the entire tube.

[0005] However, during the development of the klystron, the deviation in the size of the resonant cavity caused by calculation errors and processing tolerances often causes the resonant frequency to deviate from the design value. When the frequency deviation is large, the adjustment range of the 0.3 mm elastic diaphragm cannot meet the design requirements. In addition, if the resonant frequency needs to be corrected multiple times, the bellows and elastic diaphragm need to be stretched multiple times. Multiple over-stretching will cause the bellows and elastic diaphragm to rupture and leak, and the process of the tube production has to be interrupted or reversed, which is likely to delay the development of the klystron. Summary of the invention

[0006] In view of the above problems, the present invention provides an integrated rectangular resonant cavity structure and a frequency correction method thereof.

[0007] On the one hand, the present invention provides an integrated rectangular resonant cavity structure, including: a plurality of rectangular resonant cavities connected in series, each rectangular resonant cavity being a vacuum cavity, including a rectangular cavity body, elastic diaphragms arranged on the upper and lower sides of the rectangular cavity body, and a sealed cavity wall arranged on the outside of the elastic diaphragm; wherein the rectangular cavity body includes cavity covers on the upper and lower sides and cavity walls on the left and right sides, each cavity cover is hollow and welded with a drift head, and a drift gap is left between two opposite drift heads for drifting an input electron beam; the elastic diaphragm electrically contacts the rectangular cavity, a plurality of coupling windows are opened on the elastic diaphragm, and the center of each coupling window corresponds to the center of a drift gap; the sealed cavity wall is used to ensure the vacuum tightness of the rectangular resonant cavity.

[0008] Furthermore, the thickness of the elastic membrane is 0.3 to 0.5 mm.

[0009] Furthermore, exhaust holes are provided on the elastic diaphragm at the left and right sides of the coupling window.

[0010] Furthermore, a plurality of drift heads are coaxially arranged, and each drift head is provided with a plurality of through holes as drift channels.

[0011] Furthermore, each drift head is in the shape of a hollow cylinder, and a plurality of through holes are evenly distributed in the circumference of each drift head.

[0012] Furthermore, the cavity cover and cavity wall of the rectangular cavity are integrally formed, and multiple rectangular resonant cavities are connected in series, including: the cavity cover on the lower side of a rectangular cavity is shared with the cavity cover on the upper side of another adjacent rectangular cavity; and multiple rectangular resonant cavities share the cavity wall of a rectangular cavity along the left and right directions.

[0013] Furthermore, a plurality of grooves are formed on the sealing cavity wall, and the center of each groove corresponds to the center of a drift gap.

[0014] On the other hand, the present invention provides a frequency correction method using the above-mentioned integrated rectangular resonant cavity structure, including: during cold testing or welding, the elastic diaphragm is clamped with a clamp to ensure electrical contact between the elastic diaphragm and the rectangular cavity; when it is detected that the resonant frequency of the rectangular resonant cavity is lower than the design value, the elastic diaphragm is deformed into the rectangular cavity by external force, so that the volume of the rectangular cavity is reduced to increase the frequency until the resonant frequency reaches the design value; when it is detected that the resonant frequency of the rectangular resonant cavity is higher than the design value, the elastic diaphragm is deformed out of the rectangular cavity by external force, or the coupling window of the elastic diaphragm is enlarged, so that the volume of the rectangular cavity is increased to reduce the frequency until the resonant frequency reaches the design value; after the frequency tuning is completed, the sealed cavity wall is welded to the outside of the elastic diaphragm by low-temperature solder or argon arc welding to meet the vacuum airtightness requirements.

[0015] Furthermore, after the frequency tuning is completed, it also includes: after performing multiple high-temperature welding, cold testing or correcting the frequency again to ensure that the resonant frequency reaches the designed value.

[0016] Compared with the prior art, the integrated rectangular resonant cavity structure and the frequency correction method thereof provided by the present invention have at least the following beneficial effects:

[0017] (1) The integrated rectangular resonant cavity structure can be used for the high-frequency cluster section of the klystron, which not only eliminates the risk of damaging the vacuum tightness due to air leakage of the bellows or elastic diaphragm, but also can conveniently and quickly tune the frequency of the rectangular resonant cavity, which is particularly beneficial to the production of klystrons in the development stage;

[0018] (2) This method can correct the frequency of the resonant cavity by simply deforming the elastic diaphragm or expanding the size of the coupling window on the elastic diaphragm. It has a large tuning range and does not require processing in a processing workshop. The coupling window can be expanded by a simple file to achieve correction and tuning of the resonant frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0020] Figure 1 The structure of a resonant cavity of an inductive tuning method in the related art is schematically shown;

[0021] Figure 2 A schematic diagram of a structure of a resonant cavity using a capacitance tuning method in the related art is shown;

[0022] Figure 3 The structure diagram of a high frequency clustering section of an X-band klystron with an elastic diaphragm cavity wall in the related art is schematically shown;

[0023] Figure 4Schematically showing three views of an integrated rectangular resonant cavity structure according to an embodiment of the present invention;

[0024] Figure 5 The flowchart of the frequency correction method using the integrated rectangular resonant cavity structure according to the embodiment of the present invention is schematically shown.

[0025] [Description of Reference Numerals]

[0026] 1-drift head; 2-elastic diaphragm; 3-sealed cavity wall; 4-rectangular cavity. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0029] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0030] against Figure 3 The high-frequency clustering section composed of the integrated rectangular cavity shown in the figure removes the cavity wall made of the elastic diaphragm, adopts a new cavity wall structure, and provides a method for correcting the frequency. The present invention not only eliminates the risk of damaging the vacuum tightness such as leakage of the bellows or the elastic diaphragm, but also can conveniently and quickly tune the frequency of the rectangular resonant cavity, which is particularly beneficial to the production of the klystron in the development stage.

[0031] The integrated rectangular resonant cavity structure and its frequency correction method are described in detail below.

[0032] Figure 4 Three views of an integrated rectangular resonant cavity structure according to an embodiment of the present invention are schematically shown.

[0033] like Figure 4As shown, the integrated rectangular resonant cavity structure according to this embodiment includes: a plurality of rectangular resonant cavities connected in series with each other, each rectangular resonant cavity is a vacuum cavity, including a rectangular cavity 4, an elastic diaphragm 2 arranged on the upper and lower sides of the rectangular cavity 4, and a sealed cavity wall 3 arranged on the outside of the elastic diaphragm 2.

[0034] The rectangular cavity 4 includes cavity covers on the upper and lower sides and cavity walls on the left and right sides. Each cavity cover is hollow and welded with a drift head 1. A drift gap is left between two opposite drift heads 1 for drifting the input electron beam. The elastic diaphragm 2 is in electrical contact with the rectangular cavity 4. A plurality of coupling windows are provided on the elastic diaphragm 2, and the center of each coupling window corresponds to the center of a drift gap. The sealed cavity wall 3 is used to ensure the vacuum tightness of the rectangular resonant cavity.

[0035] Through the embodiment of the present invention, the cavity cover and cavity wall of the rectangular cavity 4 of the structure are processed in an integrated manner, the elastic diaphragm has a coupling window, and the sealing cavity wall 3 has a groove, wherein the elastic diaphragm with the coupling window is placed between the rectangular cavity 4 and the sealing cavity wall 3. The vacuum airtightness of the structure only needs to be ensured by the sealing cavity wall 3, and the elastic diaphragm and the rectangular cavity 4 only need good electrical contact, and there is no need to ensure the airtightness of brazing, which reduces the requirements for thin cavity walls, and has higher reliability and safety. The structure can be used for the high-frequency clustering section of the klystron.

[0036] In this embodiment, the thickness of the elastic membrane 2 is 0.3-0.5 mm.

[0037] In this embodiment, the elastic membrane 2 is provided with exhaust holes on the left and right sides of the coupling window.

[0038] Exhaust holes can also be added on the left and right sides of the coupling window. This is because the wall of the elastic diaphragm cavity is very thin. When the drift tube is leak-detecting or vacuum-evacuating, the drift tube is in a vacuum state and the elastic diaphragm will be deformed by external force. Therefore, opening an exhaust hole will release the pressure. The exhaust hole in the middle is used for both tuning the frequency and exhausting the air to release the pressure.

[0039] In this embodiment, a plurality of drift heads 1 are coaxially arranged, and each drift head 1 is provided with a plurality of through holes as drift channels.

[0040] Furthermore, each drift head 1 is in a hollow cylindrical shape, and a plurality of through holes are evenly distributed in the circumferential direction on each drift head 1 .

[0041] In this embodiment, the cavity cover and cavity wall of the rectangular cavity 4 are integrally formed, and multiple rectangular resonant cavities are connected in series, including: the cavity cover on the lower side of a rectangular cavity 4 is shared with the cavity cover on the upper side of another adjacent rectangular cavity 4; and multiple rectangular resonant cavities share the cavity wall of a rectangular cavity 4 along the left and right directions.

[0042] In this embodiment, the sealing cavity wall 3 is provided with a plurality of grooves, and the center of each groove corresponds to the center of a drift gap.

[0043] The following describes the installation method of the integrated rectangular resonant cavity structure provided by the embodiment of the present invention. After the processing of each part is completed, a preliminary cold test is required first. During the cold test, the rectangular cavity and the cold test fixture are installed in the following manner: first, the elastic diaphragm with the coupling window is installed into the integrated rectangular cavity, and then the sealing cavity wall with the groove is installed, and finally the above parts are fixed and tightened with a fixture to ensure good electrical contact.

[0044] Based on the above disclosure, the present invention also provides a frequency correction method using the above integrated rectangular resonant cavity structure. Figure 5 The method is described in detail.

[0045] Figure 5 A flow chart of a frequency correction method using the above-mentioned integrated rectangular resonant cavity structure according to an embodiment of the present invention is schematically shown.

[0046] like Figure 5 As shown, the frequency correction method using the above-mentioned integrated rectangular resonant cavity structure according to this embodiment may include operations S510 to S540.

[0047] In operation S510, during cold testing or welding, the elastic diaphragm is clamped by a clamp to ensure electrical contact between the elastic diaphragm and the rectangular cavity.

[0048] The elastic diaphragm with a coupling window is set between the rectangular cavity and the sealed cavity wall. It needs to be clamped with a fixture during cold testing or welding to ensure good electrical contact during testing and reduce detuning caused by high-temperature welding deformation and poor electrical contact.

[0049] In operation S520, when it is detected that the resonant frequency of the rectangular resonant cavity is lower than the design value, an external force is used to deform the elastic diaphragm into the rectangular cavity to reduce the volume of the rectangular cavity to increase the frequency until the resonant frequency reaches the design value.

[0050] In operation S530, when it is detected that the resonant frequency of the rectangular resonant cavity is higher than the design value, an external force is used to deform the elastic diaphragm out of the rectangular cavity, or the coupling window of the elastic diaphragm is enlarged to increase the volume of the rectangular cavity to reduce the frequency until the resonant frequency reaches the design value.

[0051] Specifically, when the resonant frequency of the rectangular resonant cavity is higher than the design value, the elastic diaphragm can be deformed outside the rectangular cavity by external force to increase the volume of the rectangular cavity to reduce the frequency; or the coupling window of the elastic diaphragm can be enlarged to couple out the magnetic field in the cavity, which is equivalent to increasing the volume of the rectangular cavity, thereby reducing the resonant frequency. The larger the coupling window, the more the frequency is reduced, until the resonant frequency reaches the design value.

[0052] It should be noted that there is no strict order between operation S520 and operation S530, and a corresponding frequency adjustment method can be adopted according to the magnitude of the detected real-time resonance frequency. Compared with operation S530, operation S520 is relatively simple.

[0053] In operation S540, after the frequency tuning is completed, the sealing cavity wall is welded to the outer side of the elastic diaphragm by using low temperature solder or argon arc welding to achieve vacuum airtightness requirements.

[0054] Through the embodiments of the present invention, the frequency of the resonant cavity can be corrected by simply deforming the elastic diaphragm or expanding the size of the coupling window on the elastic diaphragm, with a large tuning range, and no need to go to a processing workshop for processing. The coupling window can be expanded by a simple file to achieve correction and tuning of the resonant frequency. This also confirms that the above-mentioned integrated rectangular resonant cavity structure can be used for the high-frequency cluster section of the klystron.

[0055] In addition, if the detected resonant frequency of the rectangular resonant cavity is suitable and does not need to be corrected, a coupling window of a certain size needs to be reserved on the elastic diaphragm as a vent hole. The vent hole can ensure that the elastic diaphragm is not deformed by atmospheric pressure during leak detection, drying and exhaust, etc., which may cause the cavity frequency to change.

[0056] Furthermore, after the frequency tuning in the above operation S540 is completed, it may also include: after performing high temperature welding for multiple times, cold testing or correcting the frequency again to ensure that the resonant frequency reaches the designed value.

[0057] Therefore, the embodiment of the present invention not only eliminates the risk of damaging the vacuum tightness due to air leakage of the bellows or elastic diaphragm, but also can conveniently and quickly tune the frequency of the rectangular resonant cavity, which is particularly beneficial to the production of klystrons in the development stage.

[0058] Some block diagrams and / or flow charts are shown in the accompanying drawings. It should be understood that some blocks or combinations thereof in the block diagrams and / or flow charts may be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that these instructions, when executed by the processor, may create a device for implementing the functions / operations described in these block diagrams and / or flow charts.

[0059] In addition, the terms "first" and "second" are used only for descriptive purposes and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the feature. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In addition, the word "one" or "an" preceding an element does not exclude the presence of multiple such elements.

[0060] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An integrated rectangular resonant cavity structure, characterized in that: include: A plurality of rectangular resonant cavities connected in series, each of the rectangular resonant cavities being a vacuum cavity, comprising a rectangular cavity, elastic diaphragms disposed on upper and lower sides of the rectangular cavity, and a sealed cavity wall disposed outside the elastic diaphragm; The rectangular cavity includes cavity covers on the upper and lower sides and cavity walls on the left and right sides. Each cavity cover is hollow and welded with a drift head. A drift gap is left between two opposite drift heads for drifting the input electron beam. The elastic diaphragm is in electrical contact with the rectangular cavity, a plurality of coupling windows are formed on the elastic diaphragm, and the center of each coupling window corresponds to the center of one of the drift gaps; The sealed cavity wall is used to ensure the vacuum airtightness of the rectangular resonant cavity; When it is detected that the resonant frequency of the rectangular resonant cavity is lower than the design value, an external force is used to deform the elastic diaphragm into the rectangular cavity, so that the volume of the rectangular cavity is reduced to increase the frequency until the resonant frequency reaches the design value; When it is detected that the resonant frequency of the rectangular resonant cavity is higher than the design value, an external force is used to deform the elastic diaphragm out of the rectangular cavity, or the coupling window of the elastic diaphragm is enlarged to increase the volume of the rectangular cavity to reduce the frequency until the resonant frequency reaches the design value.

2. The integrated rectangular resonant cavity structure according to claim 1, characterized in that: The thickness of the elastic diaphragm is 0.3-0.5 mm.

3. The integrated rectangular resonant cavity structure according to claim 1, characterized in that: The elastic diaphragm is provided with exhaust holes on the left and right sides of the coupling window.

4. The integrated rectangular resonant cavity structure according to claim 1, characterized in that: The plurality of drift heads are coaxially arranged, and each of the drift heads is provided with a plurality of through holes as drift channels.

5. The integrated rectangular resonant cavity structure according to claim 4, characterized in that: Each of the drift heads is in a hollow cylindrical shape, and the plurality of through holes are evenly distributed in the circumference of each of the drift heads.

6. The integrated rectangular resonant cavity structure according to claim 1, characterized in that: The cavity cover and cavity wall of the rectangular cavity are integrally formed, and the multiple rectangular resonant cavities are connected in series with each other, including: The cavity cover on the lower side of one of the rectangular cavities is shared with the cavity cover on the upper side of another adjacent rectangular cavity; The plurality of rectangular resonant cavities share a cavity wall of the rectangular cavity along the left-right direction.

7. The integrated rectangular resonant cavity structure according to claim 1, characterized in that: The sealing cavity wall is provided with a plurality of grooves, and the center of each groove corresponds to the center of a drift gap.

8. A frequency correction method using the integrated rectangular resonant cavity structure according to any one of claims 1 to 7, characterized in that: include: During cold testing or welding, the elastic diaphragm is clamped with a clamp to ensure electrical contact between the elastic diaphragm and the rectangular cavity; When it is detected that the resonant frequency of the rectangular resonant cavity is lower than the design value, an external force is used to deform the elastic diaphragm into the rectangular cavity, so that the volume of the rectangular cavity is reduced to increase the frequency until the resonant frequency reaches the design value; When it is detected that the resonant frequency of the rectangular resonant cavity is higher than the design value, an external force is used to deform the elastic diaphragm out of the rectangular cavity, or the coupling window of the elastic diaphragm is enlarged to increase the volume of the rectangular cavity to reduce the frequency until the resonant frequency reaches the design value; After the frequency tuning is completed, the sealed cavity wall is welded to the outer side of the elastic diaphragm by using low temperature solder or argon arc welding to achieve the vacuum airtightness requirement.

9. The frequency correction method according to claim 8, characterized in that: After the frequency tuning is completed, the method further includes: After multiple high-temperature weldings, cold test or correct the frequency again to ensure that the resonant frequency reaches the designed value.

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