Device and method for determining size of inner tuning nail of distributed klystron

Abstract

The invention provides a device and method for determining the size of an internal tuning nail of a multi-gap cavity of a distributed action klystron, and the device comprises a cold testing mold which is provided with a mounting hole extending in a first direction, and the mounting hole is suitable for the insertion of a ladder core plate of the internal tuning nail to be matched; each tuning plug block group comprises at least one tuning plug block, a first end of each tuning plug block is arranged in the cold test mold in a penetrating manner and is pressed against each opening formed by the ladder core plate, each first end is provided with a convex part, and the convex part extends into each resonant cavity formed by the ladder core plate and the cold test mold from the opening of the ladder core plate; the fastening assembly is used for limiting each tuning plug block in the same tuning plug block group on the ladder core plate so as to seal each resonant cavity through the tuning plug blocks and the cold test mold; wherein each tuning plug block group is arranged on the cold test mold in a replaceable manner, and the thickness, matched with the design frequency of the resonant cavity, of the test frequency corresponding to the convex part extending into the resonant cavity is determined as the target thickness of the inner tuning nail.

Description

Technical Field

[0001] The present disclosure relates to the technical field of microwave and millimeter wave electric vacuum devices, and in particular to a device and method for determining the size of an internal tuning pin of a distributed action klystron. Background Art

[0002] Millimeter-wave distributed-action klystrons operate in the frequency range of 30-300 GHz, and can meet the application requirements of mobile platforms such as vehicles, aircraft, and satellites for miniaturized, high-power microwave sources. In this type of device, in order to effectively improve the characteristic impedance, withstand voltage, and heat capacity of the resonant cavity and minimize the circuit length, a multi-gap cavity structure is usually used as a high-frequency circuit unit.

[0003] The internal tuning pin realizes the electromagnetic characteristics of the resonant cavity (such as resonant frequency and quality factor (Q value)) by changing the electric field distribution inside the resonant cavity.

[0004] During the high-frequency circuit design phase, the length of the internal tuning pins in each resonant cavity has been calculated. However, in the actual structure, due to the frequency deviation introduced by the processing and technological process, the appropriate length of the internal tuning pins is often different from the design value. Summary of the invention

[0005] In view of this, the present disclosure provides a device and method for determining the size of an internal tuning pin by cold measurement, which can eliminate the frequency deviation introduced by the processing error of the parts.

[0006] As one aspect of the embodiments of the present disclosure, there is provided a device for determining the size of the internal tuning pin of a distributed action klystron, comprising a cold test mold, a plurality of tuning plug groups and a fastening assembly. The cold test mold has a mounting hole extending along a first direction, and the mounting hole is suitable for inserting a ladder core plate to be matched with the internal tuning pin. Each of the above-mentioned tuning plug groups includes at least one tuning plug, and the first end of each of the above-mentioned tuning plugs is inserted into the above-mentioned cold test mold and pressed against each opening formed by the above-mentioned ladder core plate, and each of the above-mentioned first ends has a convex portion, and the above-mentioned convex portion extends from the opening of the above-mentioned ladder core plate to each resonant cavity formed by the above-mentioned ladder core plate and the above-mentioned cold test mold, and the convex portions of the above-mentioned tuning plugs in different above-mentioned tuning plug groups have different thicknesses. The fastening assembly is suitable for restricting each of the above-mentioned tuning plugs in the same above-mentioned tuning plug group on the above-mentioned ladder core plate, so as to seal each of the above-mentioned resonant cavities through the above-mentioned tuning plug and the above-mentioned cold test mold. Each group of the above tuning plugs can be replaceably arranged on the above cold test mold, and the thickness of the test frequency corresponding to the protrusion extending into the above resonance cavity and matching the design frequency of the above resonance cavity is determined as the target thickness of the above internal tuning pins.

[0007] According to an embodiment of the present disclosure, the fastening assembly includes a first clamp, a second clamp and an installation unit. The first clamp abuts against the tuning plug, the second clamp is opposite to the first clamp, and the second clamp abuts against the side wall of the cold test mold away from the tuning plug. The installation unit is arranged on the first clamp and the second clamp, and is located at the periphery of the cold test mold and the tuning plug, and is suitable for making the first clamp and the second clamp cooperate to extrude the tuning plug and the cold test mold in a second direction orthogonal to the first direction.

[0008] According to an embodiment of the present disclosure, the above-mentioned fastening assembly also includes a plurality of pressing members, which are respectively installed on the first clamping member, and each of the pressing members is suitable for cooperating with the first clamping member in the second direction to press each of the tuning plugs against the ladder core plate.

[0009] According to an embodiment of the present disclosure, each of the above-mentioned pressing members includes a pressing rod and a pressing plate, wherein the first end of the above-mentioned pressing rod abuts against the above-mentioned tuning plug, and the second end of the above-mentioned pressing rod extends in a direction away from the above-mentioned tuning plug and protrudes from the above-mentioned first clamping member. The pressing plate is installed on the above-mentioned first clamping member by bolts and abuts against the second end of the above-mentioned pressing rod. The above-mentioned bolt is threadedly engaged with the above-mentioned first clamping member, so that the above-mentioned pressing plate pushes the above-mentioned pressing rod to move toward the above-mentioned tuning plug.

[0010] According to an embodiment of the present disclosure, the mounting unit includes a plurality of rods and a plurality of locking members. Each of the rods passes through the first clamp and the second clamp, and extends from two side surfaces of the first clamp and the second clamp that are away from each other. Every two locking members are threadedly coupled to both ends of one of the rods, so that the tuning plug and the cold test mold are clamped between the first clamp and the second clamp by tightening the locking members.

[0011] According to an embodiment of the present disclosure, a plurality of coupling holes respectively penetrating the plurality of resonant cavities are formed on the side wall of the cold test mold near the second clamping member. The second clamping member is configured in a ring shape to allow one end of a plurality of waveguides from the outside to pass through the ring-shaped second clamping member and be coupled and connected to the plurality of resonant cavities through the plurality of coupling holes; an external analyzer is connected to the other end of the plurality of waveguides to obtain the test frequency through the waveguides.

[0012] According to an embodiment of the present disclosure, the cold test mold comprises a main body and two blocking parts. The mounting hole is formed on the main body, and the two blocking parts extend from both sides of the main body in the first direction, respectively, in a direction toward the first clamping member, wherein the first clamping member is arranged between the two blocking parts to limit the relative position between the first clamping member and the cold test mold in the first direction.

[0013] According to an embodiment of the present disclosure, a second end of each tuning plug opposite to the first end protrudes from the cold test mold.

[0014] As another aspect of the embodiments of the present disclosure, a method for determining the thickness of an internal tuning pin of a distributed action klystron using any of the above-mentioned devices for determining the size of an internal tuning pin of the distributed action klystron is provided, comprising:

[0015] Insert the ladder core plate with the internal tuning pin to be matched into the mounting hole of the cold test mold;

[0016] Placing each tuning plug in the first tuning plug group on the opening formed by the ladder core plate;

[0017] The fastening assembly presses each of the above-mentioned tuning plugs against the opening formed by the above-mentioned ladder core plate, so as to seal each of the above-mentioned resonant cavities through each of the above-mentioned tuning plugs and the above-mentioned cold test mold;

[0018] The test frequency of the resonant cavity under the first tuning plug group is obtained, and the thickness of the convex portion extending into the resonant cavity that matches the corresponding test frequency of the resonant cavity and the design frequency of the resonant cavity is determined as the target thickness of the inner tuning pin.

[0019] According to an embodiment of the present disclosure, the above method further includes:

[0020] In the case where the above test frequency does not match the above design frequency,

[0021] Taking out the first tuning plug group pressed against the ladder core plate;

[0022] Another tuning plug group having a convex portion with a different thickness from that of the first tuning plug group is used as the first tuning plug group, and the test frequency is reacquired until the test frequency matches the design frequency.

[0023] According to the device for determining the size of the inner tuning pin of the multi-gap resonant cavity of the distributed action klystron according to the embodiment of the present disclosure, each group of tuning plugs is replaceably arranged on the cold test mold, and by replacing the tuning plugs, the size of the protrusion of the tuning plug extending into the resonant cavity is made different. When the corresponding test frequency of the protrusion extending into the resonant cavity matches the design frequency of the resonant cavity, the thickness of the protrusion is determined as the target thickness of the inner tuning pin, so as to achieve the determination of the target thickness of the inner tuning pin during the cold test, and there is no need to adjust the frequency of the resonant cavity through the diaphragm of the distributed action klystron during the cold test stage. In the subsequent assembly brazing process, the frequency change caused by the slight deformation of the resonant cavity or other structures can be compensated for twice during the hot test stage by raising the pressure of the diaphragm. Not only the frequency adjustment range of the resonant cavity is guaranteed while reducing the adjustment amount of the diaphragm deformation, but also the risk of vacuum sealing failure caused by diaphragm rupture can be significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0025] Figure 1 A half-cutaway perspective view of a device according to an embodiment of the present disclosure is schematically shown;

[0026] Figure 2 Schematically shows Figure 1 A partial enlarged view of the device shown;

[0027] Figure 3 A perspective view schematically shows a tuning plug according to an embodiment of the present disclosure;

[0028] Figure 4 Schematically shows a perspective view of an inner tuning pin according to an embodiment of the present disclosure;

[0029] Figure 5 schematically illustrates a side view of an inner tuning pin according to an embodiment of the present disclosure;

[0030] Figure 6 A partial cross-sectional view of a determined distributed action klystron according to an embodiment of the present disclosure is schematically shown;

[0031] Figure 7 A flowchart schematically shows a method for determining the thickness of an inner tuning pin according to an embodiment of the present disclosure; and

[0032] Figure 8 The figure schematically shows a cavity group delay curve in a cold test state according to an embodiment of the present disclosure.

[0033] The following are the descriptions of the reference numerals:

[0034] 1-Cold test mold;

[0035] 11- coupling hole;

[0036] 12-main body;

[0037] 13- blocking part;

[0038] 2-Internal tuning nail tuning plug;

[0039] 21-Protrusion;

[0040] 3- Fastening components;

[0041] 31- first clamping member;

[0042] 32- second clamping member;

[0043] 33-installation unit;

[0044] 331- rod;

[0045] 332-locking member;

[0046] 34-pressing member;

[0047] 341-pressure rod;

[0048] 342-pressing plate;

[0049] 343-bolt;

[0050] 4- ladder core plate;

[0051] 5- diaphragm;

[0052] 6-External tuning nails;

[0053] 7-Internal tuning nail;

[0054] 8-Tuning rod;

[0055] 9-Tuning bracket;

[0056] 10-Tuning plate. DETAILED DESCRIPTION

[0057] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0058] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. 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.

[0059] All terms used herein, including technical and scientific terms, 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.

[0060] When using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, and C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc. When using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, or C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.

[0061] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only reference directions of the drawings and are not intended to limit the scope of protection of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present disclosure.

[0062] In the process of implementing the present disclosure, it was found that in order to obtain a higher interaction efficiency, the diameter of the electron injection channel is about 1 / 10 of the working wavelength, which makes it difficult to use the traditional double-probe excitation method to detect the electric field of the resonant cavity working mode, especially when the inherent quality factor of the resonant cavity is low, the method will face the problem of failure.

[0063] The method of using dual probes to measure the frequency of the resonant cavity is that the swept frequency signal generated by the swept frequency signal source passes through the excitation source probe to establish a high-frequency field inside the resonant cavity. The changing electric field is then transmitted to the receiving probe. The amplitude of the electric field in the resonant cavity gap changes with frequency and is displayed on the oscilloscope through the detector. The extreme position of the corresponding amplitude-frequency response curve is the resonant frequency of the cavity.

[0064] However, as the size of the cavity continues to decrease and the operating frequency enters the millimeter wave band, the diameter of the cavity drift channel also becomes very small, usually less than 1mm in the millimeter wave band. At this time, in order to ensure the accuracy of frequency measurement, a coaxial probe with a thinner outer diameter is required, which reduces the energy input into the cavity through the probe, making it difficult to offset the influence of parasitic capacitance, and the test error becomes larger.

[0065] What is more serious is that for a cavity with a low intrinsic quality factor, the use of a thinner coaxial probe will not be able to effectively excite the working mode electric field, causing the method to fail.

[0066] Figure 1 Schematically shows a half-cutaway perspective view of a device according to an embodiment of the present disclosure, Figure 2 Schematically shows Figure 1 A partial enlarged view of the device shown, Figure 3 A perspective view of a tuning block according to an embodiment of the present disclosure is schematically shown.

[0067] As one aspect of an embodiment of the present disclosure, a device for determining the size of an inner tuning pin of a multi-gap cavity of a distributed action klystron is provided. Figures 1 to 3 As shown, the device includes a cold test mold 1, a plurality of tuning plug groups and a fastening assembly 3. The cold test mold 1 has a mounting hole extending along a first direction, and the mounting hole is suitable for inserting a ladder core plate 4 to be matched with an internal tuning pin 7. Each tuning plug group includes at least one tuning plug 2, and the first end of each tuning plug 2 is inserted into the cold test mold 1 and pressed against each opening formed by the ladder core plate 4. Each first end has a convex portion 21, and the convex portion 21 extends from the opening of the ladder core plate 4 to each resonant cavity formed by the ladder core plate 4 and the cold test mold 1. The convex portions 21 of the tuning plugs 2 in different tuning plug groups have different thicknesses. The fastening assembly 3 is suitable for restricting each tuning plug 2 in the same tuning plug 2 group to the ladder core plate 4, so as to seal each resonant cavity through the tuning plug 2 and the cold test mold 1. Among them, each group of tuning plugs 2 are replaceably arranged on the cold test mold 1, and the thickness of the protrusion 21 extending into the resonance cavity corresponding to the test frequency and matching the design frequency of the resonance cavity is determined as the target thickness of the internal tuning pin 7.

[0068] According to the device for determining the size of the inner tuning pin 7 of the multi-gap resonant cavity of the distributed action klystron according to the embodiment of the present disclosure, each group of tuning plugs 2 are replaceably arranged on the cold test mold 1, and by replacing the tuning plugs 2, the size of the protrusion 21 of the tuning plug 2 extending into the resonant cavity is different. When the corresponding test frequency of the protrusion 21 extending into the resonant cavity matches the design frequency of the resonant cavity, the thickness of the protrusion 21 is determined as the target thickness of the inner tuning pin 7, so as to achieve the determination of the target thickness of the inner tuning pin 7 during the cold test, and there is no need to adjust the frequency of the resonant cavity through the diaphragm 5 of the distributed action klystron in the cold side stage. In the subsequent assembly brazing process, the frequency change caused by the slight deformation of the resonant cavity or other structures can be compensated for twice in the hot test stage by pressing the diaphragm 5. Not only the frequency adjustment range of the resonant cavity is guaranteed while reducing the deformation adjustment amount of the diaphragm 5, but also the risk of vacuum sealing failure caused by the rupture of the diaphragm 5 can be significantly reduced.

[0069] In an exemplary embodiment, the protrusions 21 of the tuning plugs 2 in each tuning plug group may have the same thickness.

[0070] In another exemplary embodiment, the protrusions 21 of the tuning plugs 2 in each tuning plug group may have different thicknesses.

[0071] In an illustrative embodiment, the thicknesses of the protrusions 21 of the tuning plugs 2 in each group of the multiple tuning plug groups are arranged in equal and different thicknesses.

[0072] According to the embodiments of the present disclosure, each group of tuning plugs has convex portions 21 of different thicknesses, which can cover a wider frequency range and facilitate finding the tuning plug 2 closest to the design frequency of the resonant cavity.

[0073] According to the embodiment of the present disclosure, each group of tuning plugs is tightly pressed against the opening of the ladder core plate 4 through the cooperation of the cold test mold and the fastening assembly 3 .

[0074] According to an embodiment of the present disclosure, the thickness of the protrusion of the tuning plug 2 is the dimension of the protrusion in the second direction.

[0075] Figure 4 Schematically shows a perspective view of an inner tuning pin according to an embodiment of the present disclosure, Figure 5 A side view of an inner tuning pin according to an embodiment of the present disclosure is schematically shown.

[0076] According to the embodiments of the present disclosure, Figures 3 to 5 As shown, the shape of the protrusion 21 of the tuning plug 2 is similar to the shape of the inner tuning pin 7 .

[0077] like Figure 4 and Figure 5 As shown, one end of the inner tuning pin 7 is provided with a connection portion for welding to the diaphragm 5 of the distributed action klystron. The thickness h of the protrusion 21 of the tuning plug 2 is the target thickness of the inner tuning pin 7 as a whole. , that is, h = .

[0078] According to an embodiment of the present disclosure, the ladder core board 4 is a high-frequency ladder core board 4 .

[0079] According to the embodiment of the present disclosure, the cold test mold 1 is equivalent to distributing the actual high frequency band of the klystron.

[0080] According to the embodiment of the present disclosure, a series of tuning plugs 2 with equidistantly arranged thicknesses (h) of the convex blocks can be pre-processed. The thickness of each tuning plug 2 extending into the resonant cavity (composed of the high-frequency ladder core plate 4 and the cold test mold 1) is different. The convex blocks of different thicknesses will correspond to different resonant frequencies. By replacing the tuning plugs 2 with different thicknesses h, the test frequency of the resonant cavity is made close to the design value. The thickness h value at this time is recorded as the target thickness of the inner tuning pin 7. .

[0081] According to the determined thickness h of the tuning plug 2, the target thickness of the inner tuning pin 7 is cut off. =h of the internal tuning pin 7, which is used in the actual resonant cavity.

[0082] Figure 6 A partial cross-sectional view of a determined distributed action klystron according to an embodiment of the present disclosure is schematically shown.

[0083] In the process of implementing the present disclosure, it is found that Figure 6 As shown, in the determined distributed action klystron, an inner tuning pin 7 is provided below the diaphragm 5, and an outer tuning pin 6 with a built-in thread is provided above the diaphragm 5. The diaphragm 5 can be effectively lifted up or pressed down by a screw mechanism that can rotate around an axis, thereby changing the position of the inner tuning pin 7 in the cavity, thereby achieving frequency adjustment.

[0084] like Figure 6 As shown, the screw mechanism includes a tuning plate 10, a tuning rod 8 and a tuning bracket 9. The tuning rod 8 is a mechanism for adjusting the position of the diaphragm 5. By rotating, the diaphragm 5 can be moved up and down, thereby adjusting the position of the internal tuning pin 7 in the cavity to achieve frequency adjustment. The tuning bracket 9 fixes the tuning rod 8 on the high-frequency band structure to provide support. The tuning plate 10 further fixes the tuning rod 8 to prevent it from being displaced or tilted during rotation.

[0085] The fixing method of the tuning rod 8 ensures that it remains stable during the rotation process, avoiding frequency adjustment errors caused by displacement or tilt. The fixing structure can withstand certain mechanical stresses to avoid damage to the tuning rod 8 during use.

[0086] An external tuning pin 6 is welded to the outside of the diaphragm 5. To improve the displacement accuracy, the tuning rod 8 is screwed to the external tuning pin 6 by a fine thread. The position of the tuning rod 8 is fixed on the high frequency band by the tuning bracket 9 and the tuning pressure plate 10. The tuning rod 8 can only rotate around its own axis and cannot move along the axis.

[0087] like Figures 3 to 6As shown, the structure of the first end of the inner tuning pin 7 is exactly the same as the structure of the protrusion 21 of the tuning plug 2. The second end of the inner tuning pin 7 is a connection portion that contracts radially inward, so that when the second end is welded to the diaphragm 5, the inner tuning pin 7 can be welded to the inner side of the diaphragm 5 through a smaller connection portion, so that the diaphragm 5 can move within a certain range of lifting or pressing down, eliminating the frequency deviation introduced again by slight deformation of the cavity structure in the subsequent process. Since the diaphragm 5 is in an undeformed equilibrium position during the cold test stage, the diaphragm 5 can be lifted and pressed to perform secondary compensation during the hot test stage, effectively reducing the deformation of the diaphragm 5 and reducing the risk of rupture.

[0088] According to the embodiments of the present disclosure, Figure 1 and Figure 2 As shown, the ladder core plate 4 contains one or more resonant cavities, which are usually made of metal and can be adjusted to a specific microwave frequency. The design of the resonant cavity determines the operating frequency of the klystron.

[0089] According to the embodiments of the present disclosure, Figure 1 As shown, the fastening assembly 3 includes a first clamping member 31, a second clamping member 32 and a mounting unit 33. The first clamping member 31 abuts against the tuning plug 2, the second clamping member 32 is opposite to the first clamping member 31, and the second clamping member 32 abuts against the side wall of the cold test mold 1 away from the tuning plug 2. The mounting unit 33 is arranged on the first clamping member 31 and the second clamping member 32, and is located at the periphery of the cold test mold 1 and the tuning plug 2, and is suitable for making the first clamping member 31 and the second clamping member 32 cooperate to extrude the tuning plug 2 and the cold test mold 1 in a second direction orthogonal to the first direction, so that the tuning plug 2 and the cold test mold 1 can be uniformly stressed, local stress concentration can be avoided, and the reliability of the device can be improved.

[0090] In such an embodiment, the first clamping member 31 and the second clamping member 32 are brought close to each other through the installation unit 33, driving a group of tuning plugs 2 to move toward the direction close to the ladder core plate 4, so that a plurality of tuning plugs 2 in a group of tuning plugs 2 correspond one by one to a plurality of openings on the ladder core plate 4, and are pressed against the plurality of openings, thereby closing each resonant cavity.

[0091] According to the embodiments of the present disclosure, Figure 1 As shown, the fastening assembly 3 further includes a plurality of pressing members 34 , which are respectively mounted on the first clamping member 31 and are adapted to cooperate with the first clamping member 31 in the second direction to press the plurality of tuning plugs 2 against the ladder core plate 4 .

[0092] According to the embodiment of the present disclosure, the plurality of pressing members 34 cooperate with the first clamping member 31 to further squeeze the tuning plug 2 in a direction perpendicular to the ladder core plate 4, thereby enhancing the sealing of the resonance cavity and avoiding test errors. In addition, the presence of the pressing members 34 can squeeze the tuning plug 2 in multiple directions, transmit force more evenly, and further ensure the sealing of the resonance cavity.

[0093] According to the embodiments of the present disclosure, Figure 1 As shown, each pressing member 34 includes a pressing rod 341 and a pressing plate 342. The first end of the pressing rod 341 abuts against the tuning plug 2, and the second end of the pressing rod 341 extends away from the tuning plug 2 and protrudes from the first clamping member 31. The pressing plate 342 is mounted on the first clamping member 31 by a bolt 343 and abuts against the second end of the pressing rod 341. The bolt 343 is threadedly engaged with the first clamping member 31, so that the pressing plate 342 pushes the pressing rod 341 to move toward the tuning plug 2.

[0094] According to the embodiment of the present disclosure, the high-frequency ladder core plate 4 is inserted into the cold test mold 1, and the cold test mold 1 is used to be equivalent to the high frequency band of the actual millimeter-wave distributed action klystron. The tuning plug 2 contacts the upper end of the high-frequency ladder core plate 4. The tuning plug 2 is tightly fitted with the high-frequency ladder core plate 4 by the force applied by the pressure rod 341 and the pressure plate 342. The pressure plate 342 is fixed to the upper surface of the first clamp 31 by screws on both sides, and applies a downward force to the tuning plug 2 through the pressure rod 341. The first clamp 31 and the second clamp are locked with screws and nuts to ensure that the cold test mold 1, the high-frequency ladder core plate 4 and the tuning plug 2 located between the first clamp 31 and the second clamp are in close contact, so as to minimize the test error.

[0095] In an illustrative embodiment, Figure 1 As shown, the second end of the pressure rod 341 has a mating portion extending upward, and the size of the mating portion in the radial direction is smaller than the size of the pressure rod 341, so that the pressure plate 342 can be pressed against the second end of the pressure rod 341, and the mating portion can extend in the second direction into the sliding hole on the pressure plate 342 that passes through in the second direction. The sliding hole guides the mating portion to position the pressure rod 341 in the second direction, so that the pressure rod 341 can evenly press the tuning plug 2 against the ladder core plate 4, thereby achieving good contact between the ladder core plate 4 and the tuning plug 2.

[0096] According to the embodiments of the present disclosure, Figure 1As shown, the mounting unit 33 includes a plurality of rods 331 and a plurality of locking members 332. Each rod 331 passes through the first clamping member 31 and the second clamping member 32 respectively, and extends from two side surfaces of the first clamping member 31 and the second clamping member 32 that are away from each other. Every two locking members 332 are threadedly coupled to both ends of a rod 331, so that the tuning plug 2 and the cold test mold 1 are clamped between the first clamping member 31 and the second clamping member 32 by tightening the locking members 332.

[0097] According to the embodiment of the present disclosure, each rod 331 passes through the first clamping member 31 and the second clamping member 32 respectively to form a multi-point clamping structure, which ensures uniform force between the tuning plug 2 and the cold test mold 1, more effectively ensures the sealing of the resonance cavity, and avoids test errors.

[0098] In an illustrative embodiment, the rod 331 may be a screw, and the locking member 332 may be a nut that matches the screw thread.

[0099] According to the embodiments of the present disclosure, Figure 1 and Figure 2 As shown, a plurality of coupling holes 11 respectively penetrating the plurality of resonant cavities are formed on the side wall of the cold test mold 1 near the second clamping member 32. The second clamping member 32 is configured in a ring shape to allow one end of a plurality of waveguides from the outside to pass through the ring-shaped second clamping member 32 and be coupled and connected to the plurality of resonant cavities through the plurality of coupling holes 11; the external analyzer is connected to the other end of the plurality of waveguides to obtain the test frequency through the waveguides.

[0100] In an illustrative embodiment, a coupling hole 11 is provided on the cold test mold 1, and the coupling hole 11 corresponds to the position of the intermediate resonant cavity on the high-frequency ladder core plate 4. In this way, the cold test mold 1, the high-frequency ladder core plate 4 and the tuning plug 2 can be used to form a testable external waveguide resonant cavity through an external waveguide. The resonant cavity is connected to an external straight waveguide through the coupling hole 11 to form a single-port system. When cold testing, the output port of the straight waveguide is connected to a vector network analyzer to measure the frequency of the intermediate resonant cavity.

[0101] In one illustrative embodiment, the analyzer includes a vector network analyzer.

[0102] According to the embodiments of the present disclosure, a testable external waveguide resonant cavity is constructed by using a dedicated cold test mold 1, a tuning plug 2 and a coupling hole 11, thereby realizing frequency measurement of a resonant cavity with a small channel diameter and a low quality factor.

[0103] According to the device for determining the size of the internal tuning pin 7 of the distributed action klystron according to the embodiment of the present disclosure, a coupling hole 11 penetrating the resonant cavity is opened on the cold test mold 1, and a small hole coupling method is used to couple the coupling hole 11 with the resonant cavity through the external waveguide. The working mode of the resonant cavity can be easily found, and the problem of failure of the double probe method for testing the resonant cavity with a low quality factor in a small drift channel is effectively overcome. The probe method cannot be used mainly due to three factors. First, it is difficult for a thinner coaxial probe to feed enough energy into the resonant cavity. Second, it is difficult to establish an electric field of sufficient strength in a resonant cavity with a low quality factor. Third, the parasitic capacitance between the probe and the resonant cavity causes a large deviation in the test results. For the small hole coupling method, it is only necessary to note that the frequency of the resonant cavity with a coupling hole 11 is slightly lower than that of a closed cavity without a coupling hole 11, and appropriate frequency compensation can be performed during adjustment.

[0104] According to the embodiments of the present disclosure, for an input-output cavity (i.e., a resonant cavity) having a coupling port and an external waveguide, when selecting the length of the internal tuning pin 7, a cold test can be performed directly on the cold test mold 1 in a real installation state, and only the frequency deviation generated during part processing needs to be eliminated. The target thickness of the internal tuning pin 7 can be determined by replacing the tuning plug 2 without introducing a correction amount on the target frequency (the input-output cavity itself is a non-enclosed cavity having a coupling port).

[0105] According to an embodiment of the present disclosure, the cold test mold 1 includes a main body 12 and two blocking parts 13. The mounting hole is formed on the main body 12, and the two blocking parts 13 extend from both sides of the main body 12 in the first direction, respectively, in the direction toward the first clamping member, wherein the first clamping member is arranged between the two blocking parts 13 to limit the relative position between the first clamping member and the cold test mold 1 in the first direction.

[0106] According to the embodiment of the present disclosure, the two blocking parts 13 limit the relative position between the first clamping member and the cold test mold 1, ensuring that the device remains stable during the test, avoiding vibration or tilting, and improving the accuracy of the test results.

[0107] In an exemplary embodiment, a limiting portion extending radially inward is provided at the other end of the mounting hole opposite to the insertion end, and the limiting portion limits the depth of the ladder core plate 4 inserted into the mounting hole, so that each opening on the ladder core plate 4 can correspond to each tuning plug 2 in the second direction.

[0108] In an illustrative embodiment, the mounting hole on the main body 12 may be a blind hole.

[0109] According to an embodiment of the present disclosure, the second end of each tuning plug 2 opposite to the first end protrudes out of the cold test mold 1, so that the tuning plug 2 can be replaced by using the second end.

[0110] Figure 7The flowchart of the method for determining the thickness of the inner tuning pin 7 according to the embodiment of the present disclosure is schematically shown.

[0111] As another aspect of an embodiment of the present disclosure, a method for determining the thickness of an inner tuning pin using any of the above-mentioned devices is provided, and the method includes operations S710 to S740.

[0112] In operation S710, a ladder core plate to be matched with an internal tuning pin is inserted into a mounting hole of a cold test mold.

[0113] In operation S720, each tuning plug in the first tuning plug group is placed on an opening formed by the ladder core plate.

[0114] In operation S730, the fastening assembly presses each tuning plug against the opening formed in the ladder core plate to seal each resonant cavity through each tuning plug and the cold test mold.

[0115] In operation S740, a test frequency of the resonant cavity under the first tuning plug group is obtained, and a thickness at which the test frequency corresponding to the protrusion extending into the resonant cavity matches the design frequency of the resonant cavity is determined as a target thickness of the inner tuning pin.

[0116] According to the method provided in the embodiment of the present disclosure, the length of the internal tuning pin 7 is first determined by the tuning plug 2 to eliminate the frequency deviation introduced by the processing error of the parts. At this time, the diaphragm 5 is centered and does not deform. The adjustment of the diaphragm 5 is used to eliminate the cavity frequency changes caused by subsequent process steps during thermal measurement, which effectively reduces the deformation of the cavity diaphragm 5 in the actual device and improves the reliability of the device.

[0117] According to an embodiment of the present disclosure, a method for determining the thickness of an inner tuning pin using any of the above-mentioned devices further includes:

[0118] In the case of a mismatch between the test frequency and the design frequency,

[0119] Take out the first tuning plug group pressed against the ladder core plate 4;

[0120] Another tuning plug group having a different thickness from the convex portion 21 of the first tuning plug group is used as the first tuning plug group, and the test frequency is reacquired until the test frequency matches the design frequency.

[0121] According to an embodiment of the present disclosure, removing the first tuning plug group pressed against the ladder core plate 4 includes: after loosening the fastening assembly 3, removing the first tuning plug group, and repeating operations S720 to S740 with another tuning plug group as the first tuning plug group until the test frequency approaches the design frequency.

[0122] According to the embodiments of the present disclosure, in actual use, it is noted that when measuring the single-port group delay of the coupling hole 11, the frequency of the cavity working mode will be slightly lower than the resonant frequency of the mode in the actual closed state. Therefore, the measured frequency should be slightly lower than the design value. The specific deviation value can be determined through simulation and combined with experience.

[0123] The method for determining the thickness of the internal tuning pin 7 provided in the embodiment of the present disclosure is different from the commonly used method of correcting the cavity frequency simply by deforming the diaphragm 5. In the method for determining the thickness of the internal tuning pin 7 provided in the present disclosure, the diaphragm 5 is in an undeformed equilibrium position during the cold test stage, and the working mode frequency of the resonant cavity can meet the design requirements by selecting different lengths of the internal tuning pin 7, that is, the frequency deviation introduced during the processing has been compensated by the appropriate internal tuning pin 7. In the subsequent assembly and brazing process, the frequency change caused by the slight deformation of the cavity or other structures is compensated for again during the hot test stage by pressing the diaphragm 5. Not only does it ensure the frequency adjustment range of the resonant cavity while reducing the deformation adjustment amount of the diaphragm 5, but it can also significantly reduce the risk of vacuum sealing failure caused by rupture of the diaphragm 5.

[0124] In an illustrative embodiment, a Ka-band multi-gap intermediate cavity is taken as an example to further illustrate the cavity frequency adjustment test.

[0125] Figure 8 The figure schematically shows a cavity group delay curve in a cold test state according to an embodiment of the present disclosure.

[0126] like Figure 8 As shown, the horizontal axis represents frequency / gigahertz (GHz), and the vertical axis represents time / nanosecond (ns).

[0127] The diameter of the coupling hole 11 in the cold test mold 1 is 2.6 mm, and the hole depth is 0.5 mm. The group delay calculation result for a certain middle cavity is as follows: Figure 8 As shown, the resonant frequency is 35.246 GHz, while the mode frequency of the closed cavity is 35.295 GHz. The cold test requires the test result to be as close to the former as possible. After replacing different tuning plugs 2 to measure the mode frequency, the final selected internal tuning pin 7 is 1.6 mm long, corresponding to a frequency of 35.234 GHz.

[0128] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A device for determining the size of an internal tuning pin of a distributed action klystron, characterized in that: include: A cold test mold having a mounting hole extending in a first direction, wherein the mounting hole is suitable for inserting a ladder core plate to be matched with an internal tuning pin; A plurality of tuning plug groups, each of which includes at least one tuning plug, a first end of each of which is inserted into the cold test mold and pressed against each opening formed by the ladder core plate, each of which has a convex portion, which extends from the opening of the ladder core plate to each resonant cavity formed by the ladder core plate and the cold test mold, and the convex portions of the tuning plugs in different tuning plug groups have different thicknesses; A fastening assembly, adapted to constrain each of the tuning plugs in the same tuning plug group to the ladder core plate, so as to seal each of the resonant cavities through the tuning plugs and the cold test mold; Each group of the tuning plug blocks is replaceably arranged on the cold test mold, and the thickness of the test frequency corresponding to the protrusion extending into the resonant cavity and matching the design frequency of the resonant cavity is determined as the target thickness of the internal tuning pin.

2. The device according to claim 1, characterized in that The fastening assembly comprises: A first clamping member resting against the tuning plug; a second clamping member, opposite to the first clamping member, the second clamping member abutting against a side wall of the cold test mold away from the tuning plug; and The mounting unit is arranged on the first clamping member and the second clamping member and is located at the periphery of the cold test mold and the tuning plug, and is suitable for making the first clamping member and the second clamping member cooperate to extrude the tuning plug and the cold test mold in a second direction orthogonal to the first direction.

3. The device according to claim 2, characterized in that The fastening assembly further comprises: A plurality of pressing members are respectively mounted on the first clamping member, and each of the pressing members is suitable for cooperating with the first clamping member in the second direction to press each of the tuning plugs against the ladder core plate.

4. The device according to claim 3, characterized in that Each of the pressing members comprises: A pressure rod, wherein a first end of the pressure rod abuts against the tuning plug, and a second end of the pressure rod extends away from the tuning plug and protrudes from the first clamping member; and A pressing plate, mounted on the first clamping member by bolts and resting against the second end of the pressing rod; The bolt is threadably matched with the first clamping member, so that the pressure plate pushes the pressure rod to move toward the tuning plug.

5. The device according to claim 2, characterized in that The installation unit comprises: a plurality of rods, each of which passes through the first clamping member and the second clamping member respectively and extends from two side surfaces of the first clamping member and the second clamping member that are away from each other; and A plurality of locking members, each two of which are threadedly coupled to two ends of a rod, so that the tuning plug and the cold test mold are clamped between the first clamping member and the second clamping member by tightening the locking members.

6. The device according to claim 2, characterized in that A plurality of coupling holes respectively penetrating the plurality of resonant cavities are formed on a side wall of the cold test mold close to the second clamping member; The second clamp is constructed in a ring shape to allow one end of multiple waveguides from the outside to pass through the second ring-shaped clamp and be coupled and connected to the multiple resonant cavities through the multiple coupling holes; the external analyzer is connected to the other end of the multiple waveguides to obtain the test frequency through the waveguides.

7. The device according to any one of claims 1 to 6, characterized in that The cold test mold comprises: a main body portion, the mounting hole being formed on the main body portion; and Two blocking portions extend from both sides of the main body in the first direction respectively in the direction toward the first clamping member, wherein the first clamping member is arranged between the two blocking portions to limit the relative position between the first clamping member and the cold test mold in the first direction.

8. The device according to any one of claims 1 to 6, characterized in that A second end of each tuning plug, which is opposite to the first end, protrudes from the cold test mold.

9. A method for determining the thickness of an internal tuning pin using the device according to any one of claims 1 to 8, characterized in that: include: Insert the ladder core plate with the internal tuning pin to be matched into the mounting hole of the cold test mold; Placing each tuning plug in the first tuning plug group on the opening formed by the ladder core plate; The fastening assembly presses each of the tuning plugs against the opening formed by the ladder core plate, so as to seal each of the resonant cavities through each of the tuning plugs and the cold test mold; The test frequency of the resonant cavity under the first tuning plug group is obtained, and the thickness of the protrusion extending into the resonant cavity corresponding to the test frequency and matching the design frequency of the resonant cavity is determined as the target thickness of the inner tuning pin.

10. The method according to claim 9, characterized in that Also includes: In the case where the test frequency does not match the design frequency, Taking out the first tuning plug group pressed against the ladder core plate; Another tuning plug group having a convex portion with a different thickness from that of the first tuning plug group is used as the first tuning plug group, and the test frequency is reacquired until the test frequency matches the design frequency.

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