Impedance adjusting device of magnetron waveguide system

Abstract

The invention discloses an impedance adjusting device of a magnetron waveguide system, which is characterized by comprising a waveguide tube body, a waveguide cavity is formed in the waveguide tube body, the waveguide tube body is correspondingly provided with an impedance adjusting piece capable of moving longitudinally and transversely relative to the waveguide tube body, and one end of the impedance adjusting piece can be transversely inserted into the waveguide cavity. The impedance adjusting device is beneficial to flexible adjustment of parameters of the waveguide system.

Description

Technical Field

[0001] This invention relates to the field of microwave waveguide devices, and more specifically to an impedance adjustment device for a magnetron waveguide system. Background Technology

[0002] Currently, microwave ovens are equipped with magnetrons. During the magnetron production process, testing equipment is required to perform characteristic testing on the magnetron. The aforementioned testing equipment can be referenced in Chinese Utility Model Patent Publication No. CN216310247U, "A Magnetron Primary Characteristic Testing and Adjustment Machine," and Chinese Invention Patent Application Publication No. CN120630063A, "A Magnetron Primary Characteristic Testing Device and its Calibration Method." The aforementioned testing equipment includes a waveguide system. The waveguide system has two main parameters: one is the "Standing Wave Ratio (SWR)," a key indicator measuring the impedance matching degree between the magnetron and the load (i.e., the waveguide system, which includes the terminating load). An excessively high SWR indicates severe mismatch, causing a large amount of energy to be reflected back to the magnetron, leading to reduced magnetron efficiency, increased heating, and even damage. The other parameter is the "phase," which is mainly the phase difference between the microwaves emitted by the magnetron and those reflected by the load, also reflecting the matching status of the waveguide to the magnetron. For testing purposes, it is often necessary to adjust the parameters of the waveguide system. For example, sometimes to improve test stability, we need to adjust the parameters to a state that better matches the magnetron; other times, to test the magnetron's extreme states, we need to adjust the parameters to a state that is more challenging for the magnetron. To adjust these parameters, waveguide parameter adjustment components are needed to adjust the standing wave ratio (SWR) and phase of the waveguide system. Currently, the most commonly used is the "three-pin adjuster," such as the "three-pin tuner" in Chinese Utility Model Publication No. CN217306725U. Some experiments require the control variable method, which involves keeping one of the two parameters, SWR and phase, constant while adjusting the other. For example, experiments testing the frequency pulling or phase drop of the magnetron are like this. However, the disadvantage of the three-pin adjuster is that both the SWR and phase parameters change during the adjustment process, making it difficult to adjust the SWR while maintaining a roughly constant phase. Therefore, existing impedance adjusters (impedance tuners) are not conducive to flexible adjustment of waveguide system parameters and cannot meet the requirements of the above magnetron testing. It is necessary to improve them. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide an impedance adjustment device for a magnetron waveguide system, which facilitates flexible adjustment of the waveguide system parameters.

[0004] The objective of this invention is achieved through the following technical solution.

[0005] The impedance adjustment device for a magnetron waveguide system disclosed in this invention includes a waveguide body, a waveguide cavity formed within the waveguide body, and an impedance adjustment member that can move longitudinally and laterally relative to the waveguide body. One end of the impedance adjustment member can be laterally inserted into the waveguide cavity.

[0006] Preferably, the waveguide body has a top plate, and a longitudinal adjustment and clearance groove is formed on the top plate, and the impedance adjustment element is adapted to pass through the longitudinal adjustment and clearance groove.

[0007] Preferably, the longitudinal adjustment and avoidance groove cover is provided with a movable reflective cover plate, and a cover plate through groove is formed on the movable reflective cover plate, and the impedance adjustment component adapts to pass through the corresponding cover plate through groove.

[0008] Preferably, the waveguide body is slidably connected to a longitudinal adjustment seat, and the impedance adjustment element is disposed on the longitudinal adjustment seat.

[0009] Preferably, the longitudinal adjustment seat is provided with a transverse adjustment component, and the impedance adjustment element is disposed on the transverse adjustment component.

[0010] Preferably, the lateral adjustment assembly includes a bracket, a lateral adjustment block, an adjustment screw, and a nut. The lower end of the bracket is connected to the longitudinal adjustment seat, the lateral adjustment block is slidably connected to the bracket, the nut is rotatably connected to the bracket, the adjustment screw is screwed to the nut, the adjustment screw is slidably connected to the bracket, the lower end of the adjustment screw is connected to the lateral adjustment block, and the other end of the impedance adjustment component is connected to the lateral adjustment block.

[0011] Preferably, the nut is fitted with a lateral adjustment handwheel.

[0012] Preferably, the longitudinal adjustment seat includes a platform, which is disposed on the upper side of the top plate, the bracket is installed on the upper side of the platform, a platform through groove is formed on the platform, the impedance adjustment member is adapted to pass through the corresponding platform through groove, and the movable reflective cover is disposed between the platform and the top plate.

[0013] Preferably, the longitudinal adjustment seat is provided with a front foot plate and a rear foot plate. The front foot plate is installed and connected to the front end of the platform, and the rear foot plate is installed and connected to the rear end of the platform. A first longitudinal guide rod is provided on the front side of the waveguide body. Rollers are respectively rolled on the upper and lower sides of the first longitudinal guide rod. The rollers are rotatably connected to the front foot plate. A second longitudinal guide rod is provided on the rear side of the waveguide body. The second longitudinal guide rod is adapted to pass through the rear foot plate.

[0014] Preferably, a leak-proof cover is installed on the platform, and the upper part of the impedance adjustment component is located inside the leak-proof cover.

[0015] Compared with the prior art, the beneficial effects of this invention are: by setting a waveguide cavity to be formed in the waveguide body, and the waveguide body is provided with an impedance adjustment component that can move longitudinally and laterally relative to the waveguide body, one end of the impedance adjustment component can be inserted laterally into the waveguide cavity, which is conducive to the flexible adjustment of the waveguide system parameters. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural schematic diagram of the impedance adjustment device according to the first embodiment of the present invention.

[0017] Figure 2 This is an exploded view of the impedance adjustment device of the present invention.

[0018] Figure 3 This is a schematic diagram of the impedance adjustment device of the present invention from the left side.

[0019] Figure 4 for Figure 3 A schematic diagram of the AA-direction cross-section structure.

[0020] Figure 5 for Figure 3 Schematic diagram of the BB-direction cross-section structure.

[0021] Figure 6 This is a cross-sectional view of the lateral adjustment component of the present invention from the front view.

[0022] Figure 7 This is a three-dimensional structural diagram of the lateral adjustment component of the present invention.

[0023] Figure 8 This is a schematic diagram of a waveguide system equipped with the impedance adjustment device of the present invention.

[0024] Figure 9 This is a rear-view perspective view of the impedance adjustment device according to a second embodiment of the present invention.

[0025] Figure 10 This is a cross-sectional structural schematic diagram of the impedance adjustment device according to the second embodiment of the present invention.

[0026] Labeling: Waveguide body 1; Waveguide cavity 100; Top plate 11; Longitudinal adjustment clearance groove 101; First longitudinal guide rod 12; Second longitudinal guide rod 13; Guide frame 14; Impedance adjustment component 2; Longitudinal adjustment seat 3; Platform 31; Front foot plate 32; Rear foot plate 33; Platform through groove 301; Roller 302; Lateral adjustment assembly 4; Bracket 40; Lateral adjustment block 41; Adjustment screw 42; Nut 43; Lateral adjustment handwheel 431; Guide sleeve 44; Positioning cover 45; Lateral guide post 46; Movable reflective cover 5; Leak-proof cover 6; Longitudinal adjustment handwheel 7; Gear 71; Rack 131; Cover through groove 501; Magnetron 99; Excitation cavity 901; Detection waveguide 902; Microwave load 903. Detailed Implementation

[0027] The present invention will now be further described with reference to the accompanying drawings.

[0028] The impedance adjustment device of the magnetron waveguide system of the present invention, such as Figures 1 to 7 As shown, the system includes a waveguide body 1, within which a waveguide cavity 100 is formed. The waveguide body 1 is equipped with an impedance adjustment element 2 that can move longitudinally and laterally relative to the waveguide body 1. That is, microwaves are transmitted longitudinally within the waveguide body 1. For example, the waveguide body 1 extends in the left-right direction, so "longitudinal" means "left-right." "Lateral" refers to a direction approximately perpendicular to the longitudinal direction. Therefore, the impedance adjustment element 2 can move both longitudinally and laterally. Figure 5 As shown, one end of the impedance adjustment element 2 can be inserted laterally into the waveguide cavity 100.

[0029] like Figure 8As shown, the waveguide system includes an excitation cavity 901, a detection waveguide 902, and a microwave load 903. The waveguide system can be referenced from the Chinese invention patent application publication number CN120630063A, "A magnetron primary characteristic detection device and its calibration method". The antenna of the magnetron 99 is connected to the excitation cavity 901. The waveguide body 1 of the impedance adjustment device of the present invention is connected between the excitation cavity 901 and the detection waveguide 902. The magnetron 99's antenna emits microwaves, which are transmitted through the waveguide body 1 to the detection waveguide 902, and then reach the microwave load 903. The impedance adjustment element 2 is then inserted laterally into the waveguide cavity 100. The impedance adjustment element 2 reflects the microwaves, thus creating impedance. As the depth of insertion of the impedance adjustment element 2 into the waveguide cavity 100 increases, its effect on hindering microwave transmission becomes more pronounced, meaning the impedance of the impedance adjustment device increases. Similarly, when the depth of insertion of the impedance adjustment element 2 into the waveguide cavity 100 decreases, the microwave impedance of the waveguide system is reduced. After adjustment, the impedance adjustment element 2 can be brought to a standstill, allowing the magnetron 99 to be tested under different impedance matching conditions, i.e., under different standing wave ratio parameters. After the impedance adjustment element 2 is inserted into the waveguide cavity 100, the impedance adjustment element 2 reflects microwaves (actually diffuse reflection). Combined with the effect of microwave reflection by the inner wall of the waveguide body 1, this affects the phase of the microwaves in the waveguide system. As the lateral insertion depth of the impedance adjustment element 2 increases, the impedance adjustment element 2 reflects microwaves over a larger range, and the interference of the impedance adjustment element 2 on the microwave phase also changes. When the impedance adjustment element 2 is laterally adjusted to the correct position, it can be moved longitudinally, that is, moved in the microwave transmission direction. The timing of the microwave reaching the impedance adjustment element 2 changes, which can more directly change the phase of the microwaves passing through the waveguide body 1. Thus, the left and right adjustment of the impedance adjustment element 2 can compensate for the microwave phase change caused by the change in the lateral insertion depth of the impedance adjustment element 2, so that the microwave phase is approximately kept constant. That is to say, it is equivalent to only adjusting the standing wave ratio parameter. When only the phase parameter needs to be changed, keeping the insertion depth of the impedance adjustment element 2 constant, simply adjusting the impedance adjustment element 2 left and right allows for sensitive adjustment of the phase difference between the microwave emitted by the magnetron and the microwave reflected by the load. The left and right movement of the impedance adjustment element 2 has a relatively minor impact on the impedance. After the impedance adjustment element 2 is adjusted, it can be kept stationary. As can be seen from the above, the impedance adjustment device of the magnetron waveguide system of the present invention, by setting an impedance adjustment element 2 that can move horizontally and vertically relative to the waveguide body 1, facilitates flexible adjustment of the waveguide system parameters.The impedance adjustment element 2 can be made of materials that can reflect microwaves, such as steel, copper, silver, aluminum, or metal ceramics. For example, for metal ceramics, please refer to the Chinese invention patent publication number CN112846182B, "A method for microwave in-situ synthesis of iron-based metal ceramics and iron-based metal ceramics". The number of impedance adjustment elements 2 can be set to one or two, with the two impedance adjustment elements 2 set apart from each other.

[0030] Furthermore, such as Figure 2 As shown, the waveguide body 1 has a top plate 11, and a longitudinal adjustment and clearance groove 101 is formed on the top plate 11. That is, the longitudinal adjustment and clearance groove 101 extends in the left-right direction, as shown. Figure 1 and Figure 5 As shown, the impedance adjustment element 2 adapts to pass through the longitudinal adjustment clearance groove 101, that is to say, in Figure 1 From the visual direction, the width of the longitudinal adjustment clearance groove 101 (in the front-back direction) is adapted to the thickness of the impedance adjustment member 2 (in the front-back direction), so that the impedance adjustment member 2 and the longitudinal adjustment clearance groove 101 have a small gap in the front-back direction. When the impedance adjustment member 2 is longitudinally adjusted (i.e., adjusted left and right), the impedance adjustment member 2 can move within the longitudinal adjustment clearance groove 101. The structure of the longitudinal adjustment clearance groove 101 allows one end of the impedance adjustment member 2 to be inserted into the waveguide cavity 100, while avoiding the opening of a large area on the waveguide body 1.

[0031] Furthermore, such as Figure 1 , Figure 2 and Figure 5 As shown, the longitudinal adjustment clearance groove 101 is covered with a movable reflective cover plate 5, and a cover plate through groove 501 is formed on the movable reflective cover plate 5. The impedance adjustment member 2 is adapted to pass through the corresponding cover plate through groove 501. In other words, the gap between the impedance adjustment member 2 and the cover plate through groove 501 in the horizontal direction is set to be small, but the impedance adjustment member 2 needs to be able to move up and down relative to the movable reflective cover plate 5. The movable reflective cover plate 5 can be made of aluminum. Since the movable reflective cover plate 5 covers the longitudinal adjustment clearance groove 101, the microwaves directed towards the longitudinal adjustment clearance groove 101 will be reflected back to the waveguide cavity 100 by the movable reflective cover plate 5, which can avoid significant microwave leakage. When the impedance adjustment member 2 is longitudinally adjusted, the impedance adjustment member 2 can drive the movable reflective cover plate 5 to move left and right. Since the area of ​​the movable reflective cover plate 5 is significantly larger than the area of ​​the longitudinal adjustment clearance groove 101 (at the top view angle), the movable reflective cover plate 5 still covers the longitudinal adjustment clearance groove 101.

[0032] Furthermore, such as Figure 1 and Figure 2As shown, the waveguide body 1 is slidably connected to a longitudinal adjustment seat 3, and the impedance adjustment component 2 is disposed on the longitudinal adjustment seat 3. That is to say, the longitudinal adjustment seat 3 can move left and right relative to the waveguide body 1, so that the waveguide body 1 and the longitudinal adjustment seat 3 form a sliding connection. This allows the impedance adjustment component 2 and the waveguide body 1 to be assembled into a single unit, which facilitates the easy assembly of the impedance adjustment device of the magnetron waveguide system of the present invention. Figure 8 The waveguide system shown.

[0033] Furthermore, such as Figures 1 to 5 As shown, the longitudinal adjusting seat 3 is equipped with a transverse adjusting component 4, and the impedance adjusting element 2 is mounted on the transverse adjusting component 4. That is, when the longitudinal adjusting seat 3 moves left or right, it can drive the transverse adjusting component 4 to move synchronously left or right. The transverse adjusting component 4 is used to drive the impedance adjusting element 2 to adjust laterally. Figure 1 In the embodiment shown, "lateral adjustment" specifically refers to "vertical adjustment". By setting the above-mentioned linkage structure between the lateral adjustment component 4 and the vertical adjustment seat 3, it is not necessary to set up a separate mechanism to drive the lateral adjustment component 4 to move left and right with the vertical adjustment seat 3, which helps to simplify the impedance adjustment device of the present invention.

[0034] Furthermore, the lateral adjustment assembly 4 includes a bracket 40, a lateral adjustment block 41, an adjustment screw 42, and a nut 43. The lower end of the bracket 40 is connected to the longitudinal adjustment seat 3 via a corresponding screw. The lateral adjustment block 41 is slidably connected to the bracket 40, meaning that the lateral adjustment block 41 moves in the "lateral" direction, approximately perpendicular to the "longitudinal" direction. Figure 1 In the embodiment shown, the lateral adjustment block 41 moves up and down, and the nut 43 rotates to connect the bracket 40, as shown. Figure 6 As shown, a guide sleeve 44 is installed on the upper part of the bracket 40, and a flange is formed at the lower end of the nut 43. The flange is rotatably disposed inside the upper part of the guide sleeve 44. A positioning cover 45 is installed on the top of the guide sleeve 44. The flange is disposed between the positioning cover 45 and the guide sleeve 44 in the vertical direction, thereby axially positioning the nut 43. An adjusting screw 42 is screwed onto the nut 43. The adjusting screw 42 is slidably connected to the bracket 40. Specifically, the adjusting screw 42 is adapted to pass through the guide sleeve 44, and the lower end of the adjusting screw 42 is connected to the transverse adjusting block 41 by a corresponding screw. Figure 7As shown, the other end of the impedance adjusting component 2 is connected to the transverse adjusting block 41. When the nut 43 is turned, the nut 43 drives the adjusting screw 42 to move up and down, which in turn moves the impedance adjusting component 2 laterally. To prevent the adjusting screw 42 from rotating, the bracket 40 is equipped with a transverse guide post 46, which is connected to the left end of the transverse adjusting block 41 via a linear bearing. Since turning the nut 43 allows the impedance adjusting component 2 to be adjusted laterally, stopping the turning of the nut 43 allows the impedance adjusting component 2 to remain in the working position due to the self-locking effect of the thread, making it easy to switch between adjustment and stillness for the impedance adjusting component 2.

[0035] Furthermore, such as Figure 6 As shown, the nut 43 is fitted with a transverse adjustment handwheel 431, which can be screwed with a corresponding set screw. One end of the set screw presses against the outer wall of the nut 43, allowing the user to squeeze the transverse adjustment handwheel 431 to rotate the nut 43, which facilitates operation.

[0036] Furthermore, such as Figure 1 , Figure 2 and Figure 5 As shown, the longitudinal adjustment seat 3 includes a platform 31, which is located on the upper side of the top plate 11. A bracket 40 is installed on the upper side of the platform 31. A platform through groove 301 is formed on the platform 31. The impedance adjustment member 2 adapts to pass through the corresponding platform through groove 301. A movable reflective cover plate 5 is located between the platform 31 and the top plate 11. Since the impedance adjustment member 2 moves left and right with the longitudinal adjustment seat 3, the longitudinal adjustment seat 3 does not interfere with the impedance adjustment member 2. By setting the impedance adjustment member 2 to pass through the longitudinal adjustment seat 3, rather than setting the impedance adjustment member 2 off to the outside of the longitudinal adjustment seat 3, the bracket 40 can be set at approximately the middle position of the platform 31 (in the left and right direction), which is beneficial to the force balance of the platform 31.

[0037] Furthermore, such as Figure 1 , Figure 2 and Figure 5As shown, the longitudinal adjustment seat 3 is provided with a front foot plate 32 and a rear foot plate 33. The front foot plate 32 is installed on the front end of the connecting platform 31, and the rear foot plate 33 is installed on the rear end of the connecting platform 31. The front side of the waveguide body 1 is provided with a first longitudinal guide rod 12. The upper and lower sides of the first longitudinal guide rod 12 are respectively connected to rollers 302 in a rolling manner. The rollers 302 are rotatably connected to the front foot plate 32. The front foot plate 32 is equipped with a rotating shaft. The rollers 302 are coaxially arranged on the corresponding rotating shafts. The rollers 302 are cylindrical in shape. The rear side of the waveguide body 1 is provided with The second longitudinal guide rod 13 is adapted to pass through the rear foot plate 33. Thus, the second longitudinal guide rod 13 positions the longitudinal adjustment seat 3 in a plane perpendicular to the left and right directions, while the roller 302 positions the longitudinal adjustment seat 3 vertically. When there is an error in the installation position of the front foot plate 32 in the front-back direction, the small front-back deviation of the roller 302 relative to the first longitudinal guide rod 12 does not affect the operation of the roller 302, which can compensate for the above-mentioned installation position error of the front foot plate 32 and facilitate the flexible left and right movement of the longitudinal adjustment seat 3.

[0038] Furthermore, such as Figure 1 , Figure 2 and Figure 5 As shown, a guide frame 14 is installed on the outer side of the waveguide body 1. The left and right ends of the first longitudinal guide rod 12 are respectively adapted to be inserted into the corresponding guide frame 14, and the left and right ends of the second longitudinal guide rod 13 are respectively adapted to be inserted into the corresponding guide frame 14. The guide frame 14 can be connected to the first longitudinal guide rod 12 and the second longitudinal guide rod 13 by corresponding set screws. The left and right ends of the movable reflective cover plate 5 are respectively located between the corresponding guide frame 14 and the top plate 11. Thus, the guide frame 14 can guide the movable reflective cover plate 5, which can prevent the end of the movable reflective cover plate 5 from tilting up. Specifically, a guide groove is formed on the inner side of the guide frame 14, and the movable reflective cover plate 5 is adapted to be connected to the above-mentioned guide groove.

[0039] In some embodiments, such as Figure 9 and Figure 10 As shown, a leak-proof cover 6 is installed on the platform 31. The upper part of the impedance adjustment component 2 is located inside the leak-proof cover 6. Thus, the platform through groove 301 is located within the range of the leak-proof cover 6. The top of the leak-proof cover 6 is attached to the upper end surface of the guide sleeve 44. A small amount of microwave leakage between the platform through groove 301 and the impedance adjustment component 2 is intercepted by the leak-proof cover 6, which can prevent microwave leakage to the outside. The leak-proof cover 6 can be made of steel, and a microwave absorbing sheet can be installed on the inner wall of the leak-proof cover 6.

[0040] In some embodiments, such as Figure 9 and Figure 10As shown, a groove is formed on the second longitudinal guide rod 13, and a rack 131 is installed in the groove. The longitudinal adjustment seat 3 is rotatably connected to a gear shaft. A longitudinal adjustment handwheel 7 is coaxially installed on one end of the gear shaft, and a gear 71 is formed on the other end of the gear shaft. The gear 71 meshes with the rack 131. Since the rack 131 is fixedly set, rotating the longitudinal adjustment handwheel 7 can make the gear 71 move longitudinally (i.e., left and right), thereby driving the longitudinal adjustment seat 3 and the impedance adjustment component 2 to adjust left and right, which is beneficial for the impedance adjustment component 2 to be easily adjusted longitudinally.

Claims

1. An impedance adjustment device for a magnetron waveguide system, characterized by: The application relates to a waveguide tube body (1) which is provided with a waveguide cavity (100) and an impedance adjusting part (2) which can move longitudinally and transversely relative to the waveguide tube body (1).

2. Impedance adjustment means for a magnetron waveguide system according to claim 1, characterized in that: The waveguide tube body (1) is provided with a top plate (11) which is provided with a longitudinal position adjusting avoiding slot (101), and the impedance adjusting part (2) is adapted to pass through the longitudinal position adjusting avoiding slot (101).

3. Impedance adjustment means for a magnetron waveguide system according to claim 2, characterised in that: The longitudinal position adjusting avoiding slot (101) is provided with a movable reflecting cover plate (5) which is provided with a cover plate through slot (501), and the impedance adjusting part (2) is adapted to pass through the corresponding cover plate through slot (501).

4. Impedance adjusting means for a magnetron waveguide system as claimed in claim 3, characterized in that: The waveguide tube body (1) is slidably connected with a longitudinal position adjusting base (3), and the impedance adjusting part (2) is arranged on the longitudinal position adjusting base (3).

5. Impedance adjustment means for a magnetron waveguide system according to claim 4, characterized in that: The longitudinal position adjusting base (3) is provided with a transverse position adjusting assembly (4), and the impedance adjusting part (2) is arranged on the transverse position adjusting assembly (4).

6. Impedance adjustment means for a magnetron waveguide system according to claim 5, characterized in that: The transverse position adjusting assembly (4) comprises a support (40), a transverse position adjusting block (41), a position adjusting screw (42) and a nut (43), the lower end of the support (40) is connected with the longitudinal position adjusting base (3), the transverse position adjusting block (41) is slidably connected with the support (40), the nut (43) is rotatably connected with the support (40), the position adjusting screw (42) is screwed with the nut (43), the position adjusting screw (42) is slidably connected with the support (40), the lower end of the position adjusting screw (42) is connected with the transverse position adjusting block (41), and the other end of the impedance adjusting part (2) is connected with the transverse position adjusting block (41).

7. Impedance adjustment means for a magnetron waveguide system according to claim 6, characterised in that: The nut (43) is sleeved with a transverse position adjusting hand wheel (431).

8. Impedance adjustment means for a magnetron waveguide system according to claim 7, characterised in that: The longitudinal position adjusting base (3) comprises a table plate (31) which is arranged on the upper side of the top plate (11), the support (40) is arranged on the upper side of the table plate (31), the table plate (31) is provided with a table plate through slot (301), the impedance adjusting part (2) is adapted to pass through the corresponding table plate through slot (301), and the movable reflecting cover plate (5) is arranged between the table plate (31) and the top plate (11).

9. Impedance adjustment means for a magnetron waveguide system according to claim 8, characterised in that: The longitudinal position adjusting base (3) is provided with a front foot plate (32) and a rear foot plate (33), the front end of the table plate (31) is connected with the front foot plate (32), the rear end of the table plate (31) is connected with the rear foot plate (33), the front side of the waveguide tube body (1) is provided with a first longitudinal guide rod (12), the upper and lower sides of the first longitudinal guide rod (12) are respectively connected with a roller (302) in a rolling mode, the roller (302) is rotatably connected with the front foot plate (32), the rear side of the waveguide tube body (1) is provided with a second longitudinal guide rod (13), and the second longitudinal guide rod (13) is adapted to pass through the rear foot plate (33).

10. The impedance adjusting means for the magnetron waveguide system of claim 8, wherein: The platform (31) is provided with a leakage-proof cover (6), and the upper part of the impedance adjusting member (2) is arranged in the leakage-proof cover (6).

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