Rotating multi-beam magnetron injection electron gun for planar gyrotron traveling wave tube

Abstract

The application discloses a rotating emission zone multi-injection magnetron injection electron gun structure applied to a planar gyrotron, and relates to the microwave, millimeter wave and electron optical technical fields.The structure comprises an anode and a cathode; the cathode is a central symmetrical structure and comprises a post-shaping electrode, an emission zone and a front-shaping electrode; wherein the emission zone is provided with an elliptical arc surface electron emission area which is rotated by a certain angle, and the electron emission area is laterally displaced; meanwhile, the post-shaping electrode and the front-shaping electrode are arranged as a special-shaped convex structure so as to adjust the electric field distribution.The application can control the shaping track of the elliptical electron injection to a certain extent, reduce the speed dispersion of the shaped electron injection, improve the working current of the magnetron injection electron gun, thereby increasing the output power of the planar magnetron injection electron gun and improving the efficiency of the planar gyrotron.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of microwave, millimeter wave technology and electron optics, and particularly relates to a rotating emission band multi-beam magnetron injection electron gun structure applied to a planar gyrotron. BACKGROUND

[0002] A gyrotron is a vacuum amplifier based on the mechanism of electron cyclotron maser instability, and has the characteristics of high frequency, wide frequency band and high power, and has important application prospects in the technical fields of electronic countermeasures and radar imaging. With the increasing requirements of microwave system performance, the research and development of high-frequency gyrotrons have also attracted widespread attention.

[0003] A traditional gyrotron mainly comprises a magnetron injection electron gun, a high-frequency interaction structure, a collector, a microwave input and output system. Electrons are first emitted from the magnetron injection electron gun under the action of an orthogonal electromagnetic field, and then perform cyclotron motion along a longitudinal magnetic field. At the high-frequency interaction structure, the cyclotron electrons exchange energy with the microwave injected from the input system, and the amplified microwave is output along the collector and the output system in the longitudinal direction. The remaining electrons after the wave injection interaction are intercepted by the collector. Limited by the challenges of current density and thermal power capacity, the pulse power of a traditional Ka-band gyrotron is 100-150 kW. With the development of the output power of the gyrotron to the MW level, a planar gyrotron electron beam is proposed. Compared with the traditional circular symmetric electron beam, the main technical feature of the planar gyrotron electron beam is that its aspect ratio is very large. The electron beam can have a small scale in one direction matched with the high-frequency wavelength, and a large size in the other direction according to the output power requirement of the device, so that the spatial charge effect and current density are reduced by increasing the cross section of the electron beam under the condition of constant total current, to ensure sufficient output power and improve the high-frequency interaction efficiency of the electron beam, thereby a higher output efficiency can be obtained. Therefore, the planar gyrotron electron beam has the advantages of small spatial charge, small current density and large transverse size. The planar gyrotron electron beam has great potential for the development of new vacuum electron devices with high power, high frequency and high efficiency.

[0004] However, the formation of planar electron beam is difficult, and the design of the corresponding planar magnetron injection electron gun is more difficult. Unlike the traditional circular gyrotron, when the planar electron beam is transmitted in the focusing magnetic field, the velocity shear caused by the space charge field and the external magnetic field between the beams will lead to the kink and break of the beam, which is called Diocotron instability. With the increase of the current density of the electron beam, the Diocotron instability becomes more and more serious. For the elliptical strip electron beam, when it is transmitted in the focusing magnetic field, the beam will rotate because the magnetic field forces on the two ends of the beam in the x direction are in opposite directions. In the uniform region where the magnetic field is constant, the rotation of the electron beam can be suppressed by reducing the distance between the electron beam and the waveguide wall. However, there is no good suppression measure in the process of forming the electron beam. The result of the rotation of the electron beam is that the formed electron beam has a certain angle with the x axis, so that the beams in different parts of the planar cavity have obviously different beam-wave interaction conditions, which leads to the decrease of the efficiency of the planar gyrotron and the deterioration of the output characteristics. If the rotation angle of the electron beam is too large, the height of the electron beam is greater than the length of the narrow side of the high-frequency interaction channel, which will cause a part of the electrons to be intercepted by the high-frequency interaction channel.

[0005] The performance optimization of the planar electron beam also faces challenges. In the two transverse dimensions of the circular electron beam, the angular dimension is uniform, and only the radial dimension is non-uniform; however, the two transverse dimensions of the planar electron beam are non-uniform, so the transverse non-uniformity of the planar electron beam is stronger than that of the circular electron beam, which leads to the deterioration of the velocity dispersion of the electron beam.

[0006] The Russian Academy of Sciences designed a planar magnetron injection gun for a 140GHz gyro oscillator tube, as shown in Figure 1 At a working voltage of 50kV and a current of 30A, a rectangular electron beam with a velocity ratio of 1.3, a velocity dispersion of 24%, a length of 30mm and a width of 1.8mm is formed, the interaction efficiency is 20%, and the output power is 300kW. At present, the research on planar gyrotron is mainly focused on low current, and the research on high current is less. The main reason is that high current leads to strong Diocotron instability, which increases the difficulty of forming and focusing the planar electron beam, and also affects the efficiency of beam-wave interaction, and then affects the output power. Most of the planar magnetron injection electron guns reported in the existing research are applied to planar gyro oscillator tubes, and the planar gyrotron has higher requirements for the stability of the electron beam and the design of the magnetron injection electron gun, so the research in this field is still very lacking. At present, there is no structure case that can compensate for the Diocotron instability in the process of forming the planar electron beam and the transverse inconsistency of the planar electron beam. SUMMARY

[0007] In order to solve the problems of shaping and velocity dispersion optimization of the existing Ka-band planar gyro-electron beam, the application provides a rotating emission zone multi-beam magnetron injection electron gun of a planar gyro-TWT.

[0008] In order to achieve the above-mentioned purpose, the technical scheme adopted by the application is as follows:

[0009] A rotating emission zone multi-beam magnetron injection electron gun of a planar gyro-TWT comprises an anode, a cathode arranged inside the anode, and a certain distance between the anode and the cathode.

[0010] Characterized in that the cathode is 180-degree rotationally symmetrical around the z-axis and comprises a rear shaping pole, an emission zone and a front shaping pole arranged in sequence along the z-axis.

[0011] The rear shaping pole is a special-shaped racetrack-shaped cylinder with the same shape of any cross section along the z-axis.

[0012] The special-shaped racetrack-shaped cylinder is composed of a rectangular column part, a semicircular column part arranged on both sides of the short side of the rectangular column part and a special-shaped protruding part arranged on both sides of the long side of the rectangular column part, wherein the long side of the rectangular column part is parallel to the x-axis and the short side is parallel to the y-axis; the outer side of the special-shaped protruding part is divided into four planes connected in sequence, wherein the first plane is outwardly inclined, the second plane is a parallel plane, the third plane is outwardly inclined, and the fourth plane is a transition connecting plane.

[0013] The emission zone is a racetrack-shaped structure in any cross section along the z-axis, and the size along the z-axis gradually decreases, forming an inclined emission zone; two electron emission areas coated with an emission coating are arranged on the emission zone, the electron emission areas are elliptical and located in the central region of the xy plane projection of the first to third faces of the special-shaped protruding part, and one side close to the vertex of the special-shaped protruding part is inclined to the rear shaping pole, and the other side is inclined to the front shaping pole.

[0014] The front shaping pole is a special-shaped racetrack-shaped structure in any cross section along the z-axis, and the top is chamfered to form a smooth arc surface.

[0015] Further, the distance between the midpoint of the electron emission area and the cathode central axis in the x direction is d, the projection of the transition connecting plane of the special-shaped protruding part on the x axis is 2d, and the value of d is determined by the trajectory difference between the upper and lower electron beams.

[0016] Further, the emission zone is an arc surface emission zone.

[0017] Further, the inclination angles of the first inclined surface and the third inclined surface of the special-shaped protruding part are the same or different, and the projection lengths on the x-axis are the same or different; when the projection areas of the first inclined surface and the third inclined surface on the x-axis are different, the boundary positions on both sides of the parallel surface are changed to meet the electric field matching requirement.

[0018] Further, a rear shaping pole transition section is arranged between the rear shaping pole and the emission band to realize transition connection therebetween; a front shaping pole transition section is arranged between the front shaping pole and the emission band to realize transition connection therebetween.

[0019] Further, the rear shaping pole transition section is divided into an arc-shaped transition section and a linear transition section along the z-axis; the front shaping pole transition section is divided into a linear transition section and an arc-shaped transition section along the z-axis; the two-section transition can make the electric field change more smoothly and is convenient for processing.

[0020] Further, the electron emission area is tangent to the upper and lower boundaries of the emission band respectively to reduce the size in the z-axis direction, so that the structure is more compact.

[0021] Principles and beneficial effects of the present application:

[0022] 1) The planar-type rotating electron beam can have small size and high frequency wavelength matching in one direction, and a larger size in another direction according to the output power requirement of the device, so as to maintain a high total current under the premise of maintaining a small space charge force, ensure a large enough output power, improve the high-frequency interaction efficiency of the electron beam, and further obtain a higher output efficiency.

[0023] 2) The present application sets the electron emission area as an ellipse and rotates the electron emission area to control the angular trajectory of the electron beam, compensate the influence of the Diocotron instability of the strip-shaped electron beam, and improve the beam-wave interaction efficiency.

[0024] 3) The present application laterally displaces the electron emission area to the direction to control the lateral trajectory of the electron beam, thereby eliminating the lateral drift caused by the electric field of the electron gun gun area and the axial magnetic field, making the positions of the upper and lower strip-shaped electron beams consistent, and reducing the difficulty of subsequent mode synthesis.

[0025] 4) The present application adjusts the parameters of the special-shaped protruding part of the front and rear shaping poles to adjust the electric field distribution on the emission band, compensates the inconsistency of the electromagnetic field caused by the rotating emission band and the high aspect ratio emission band, thereby optimizing the velocity dispersion of the electron beam and improving the performance of the electron beam. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1is a planar magnetron injection gun designed by the Russian Academy of Sciences.

[0027] Figure 2 is a schematic diagram of the cathode structure of a Ka-band rotating emission zone multi-beam planar magnetron injection electron gun in an embodiment.

[0028] Figure 3 is a schematic diagram of the cathode structure of a Ka-band rotating emission zone multi-beam planar magnetron injection electron gun in an embodiment.

[0029] Figure 4 is a schematic diagram of the cathode structure of a Ka-band rotating emission zone multi-beam planar magnetron injection electron gun in an embodiment.

[0030] Figure 5 is a schematic diagram of the structure of the emission zone of a Ka-band rotating emission zone multi-beam planar magnetron injection electron gun in an embodiment.

[0031] Figure 6 is a schematic diagram of the structure of the emission zone y-z section of a Ka-band rotating emission zone multi-beam planar magnetron injection electron gun in an embodiment.

[0032] Figure 7 is a schematic diagram of the structure of a Ka-band rotating emission zone multi-beam planar magnetron injection electron gun and the electron beam y-z section in an embodiment.

[0033] Figure 8 is a schematic diagram of the structure of a Ka-band rotating emission zone multi-beam planar magnetron injection electron gun and the electron beam x-z section in an embodiment.

[0034] Figure 9 is a cross-sectional view of the output electron beam of a Ka-band rotating emission zone multi-beam planar magnetron injection electron gun in an embodiment, the left image is a cross-sectional view of the output electron beam without rotating the emission zone and without performing lateral displacement on the emission zone, and the right image is a cross-sectional view of the output electron beam after rotating the emission zone and performing lateral displacement on the emission zone.

[0035] Figure 10 is a long-axis electromagnetic field distribution diagram of an elliptical emission zone of a Ka-band rotating emission zone multi-beam planar magnetron injection electron gun in an embodiment, the left image is an electromagnetic field distribution without a stepped structure, and the right image is an electromagnetic field distribution with a stepped structure.

[0036] Figure 11 is a diagram of the beam-wave interaction result of a planar gyrotron electron beam output by a Ka-band rotating emission zone multi-beam planar magnetron injection electron gun in an embodiment.

[0037] BRIEF DESCRIPTION OF DRAWINGS 1. rear forming electrode, 2. emission band, 3. front forming electrode, 4. electron gun anode shell, 5. strip-shaped electron beam, 6. transition connection structure, 7. semicircular table structure, 8. anode partition, 11. first surface of rear forming electrode, 12. second surface of rear forming electrode, 13. third surface of rear forming electrode, 14. fourth surface of rear forming electrode, 21. first surface of front forming electrode, 22. second surface of front forming electrode, 23. third surface of front forming electrode, 24. fourth surface of front forming electrode. DETAILED DESCRIPTION

[0038] The technical scheme of the present application will be further described in detail below with the example of a Ka-band rotating emission band multi-beam planar magnetron injection electron gun combined with the drawings:

[0039] The embodiment provides a rotating emission band multi-beam planar magnetron injection electron gun structure working in a Ka band, and a working mode is a rectangular waveguide TE 01 mode.

[0040] The electron gun of the embodiment comprises an anode, a cathode arranged in the anode, and an axial spacing of 12.2 mm between the anode and the cathode.

[0041] The anode is a central-symmetrical metal shell structure, and any cross section along the z axis is rectangular, and the wide side is constant and the narrow side decreases along the z axis; a layer of partition is arranged in the middle of the front end narrow side, so that the upper and lower electron beams are separated, and the influence of the space charge effect is reduced.

[0042] As shown in the drawings, the cathode in the embodiment is a central-symmetrical structure, and comprises a rear forming electrode, an emission band and a front forming electrode arranged in sequence along the z axis. Figures 2-5

[0043] The rear forming electrode is a special-shaped racetrack-shaped column with the same shape of any cross section along the z axis.

[0044] The emission band is a racetrack-shaped structure in any cross section along the z axis, and the size gradually decreases along the z axis to form an inclined arc surface emission band; two electron emission areas coated with an emission coating are arranged on the emission band, the electron emission areas are elliptical and located in the central region of the xy plane projection of the first to third special-shaped protrusions, and one side close to the vertex of the special-shaped protrusion is inclined to the rear forming electrode, and the other side is inclined to the front forming electrode. The distance between the midpoint of the electron emission area and the cathode central axis in the x direction is d; the value of d is determined by the trajectory difference between the upper and lower electron beams. The electron emission areas are tangent to the upper and lower boundaries of the emission band, so as to reduce the size in the z axis direction and make the structure more compact.

[0045] The front forming electrode is a special-shaped racetrack-shaped structure in any cross section along the z axis, and the top is chamfered to form a smooth arc surface.

[0046] ​The special-shaped runway-shaped column is composed of a rectangular column part, semicircular column parts arranged on both sides of the short edges of the rectangular column part, and special-shaped protruding parts arranged on both sides of the long edges of the rectangular column part, wherein the long edges of the rectangular column part are parallel to the x-axis, and the short edges are parallel to the y-axis; the outer side surface of the special-shaped protruding part is divided into four planes connected in sequence, wherein the first plane is outwardly inclined, the second plane is a parallel plane, the third plane is outwardly inclined, and the fourth plane is a transition connecting plane.

[0047] The rear-shaped pole and the emission band are connected by a rear-shaped pole transition section for transition connection therebetween; the front-shaped pole and the emission band are connected by a front-shaped pole transition section for transition connection therebetween.

[0048] The rear-shaped pole transition section is divided into an arc-shaped transition section and a linear transition section along the z-axis; the front-shaped pole transition section is divided into a linear transition section and an arc-shaped transition section along the z-axis; the two-section transition can make the electric field change more smoothly and is convenient for processing.

[0049] In the rear-shaped pole, the length of the first plane projected on the x-axis is db4=52 mm, and the length projected on the y-axis is db2=0.864 mm; the second plane is projected on the x-axis by a distance of db5=1 mm; the length of the third plane projected on the x-axis is db3=56 mm, and the length projected on the y-axis is db1=0.672 mm; the length of the fourth plane projected on the x-axis is 2d=14 mm.

[0050] In the front-shaped pole, the shape of any cross section along the z-axis is the same as that of any cross section along the z-axis of the rear-shaped pole, and the size is proportionally reduced, wherein df1=0.672 mm, df2=0.864 mm, df3=56 mm, df4=52 mm, and df5=1 mm.

[0051] The special-shaped runway-shaped column can improve the emission band electric field of the left half part (the third plane corresponding area) and weaken the emission band electric field of the right half part (the first plane corresponding area), so as to realize the regulation of the surface electric field of the emission band, reduce the velocity dispersion of the electron beam, and improve the performance of the electron beam.

[0052] As shown in Figure 5 two elliptical arc electron emission areas with a certain rotation angle are centrally symmetrically distributed in the electron gun, the major axis a of the elliptical emission band is 50 mm, the minor axis b is 2.5 mm, the rotation angle θ of the emission band is 4°, the total length of the emission band (i.e. the length of the first plane to the third plane projected on the x-axis) L is 109 mm, and the relative offset d of the emission band from the center of the electron gun is 7 mm. The rotated emission band can effectively regulate the trajectory of the electron beam, so that the electron beam enters the high-frequency structure in a horizontal state, and improves the interaction efficiency of the electron beam and the electromagnetic wave.

[0053] As shown in Figure 6As shown, the emitting band, the surface of which is a circular arc surface with a radius r=185mm, the arc surface emitting band is designed to help weaken the inconsistency of the surface electric field of the emitting band and improve the performance of the electron beam.

[0054] As shown in the drawings, Figure 7 , Figure 8 Two planar electron beams are emitted from the cathode. The revolving electrons pass through the acceleration zone and the adiabatic zone. Through magnetic adiabatic compression, the longitudinal energy is converted into transverse energy.

[0055] In terms of trajectory control of the planar revolving electron beam, due to the design of the emitting band, the trajectory of the electron beam can be well controlled. As shown in the drawings, Figure 9 It can be seen that the electron beam at the outlet of the electron gun has a certain angle θ2=4.6° with the horizontal plane without rotation and transverse displacement processing of the electron emitting area, and the upper and lower emitting bands have a certain position difference d1=5.2mm in the x-axis direction. After rotation and transverse displacement of the electron emitting area, the electron beam at the outlet of the electron gun has an angle θ2=0.2° with the horizontal plane, which is greatly reduced compared with the current planar magnetic control injection electron gun, which generates an electron beam with an angle θ2=1.71° with the horizontal plane. The length of the electron beam is 30mm, and the width of the electron beam is 2mm. And due to the design of the transverse displacement of the emitting band, the positions of the upper and lower electron beams in the x direction are consistent, which is beneficial to the subsequent power synthesis.

[0056] In terms of velocity dispersion optimization of the planar revolving electron beam, due to the rotation of the electron gun emitting band and the design of the high aspect ratio emitting band, the electromagnetic field distribution difference on the long axis of the emitting band will be increased, which will lead to the deterioration of the velocity dispersion. As shown in the drawings, Figure 10 The electric field of the emitting area without special-shaped protrusions shows a left-high right-low trend, which is opposite to the left-low right-high trend of the magnetic field, and the highest point of the electric field at the left end is the minimum of the magnetic field, which is prone to cause insufficient magnetic confinement and electron escape, thereby limiting the improvement of the magnetic pressure ratio. By setting the special-shaped protrusion structure, the electric field at the left end of the emitting band is significantly reduced, and the electric field at the right end is increased, which conforms to the trend of the change of the magnetic field. The velocity dispersion of the electron beam is reduced from 6.53% to 3.33%, and the performance of the electron beam is optimized. Compared with the current planar magnetic control injection electron gun with a velocity dispersion of 25% to 30%, the equivalent velocity dispersion of the electron beam of the embodiment is 6.7% under the same velocity dispersion algorithm, and the performance of the electron beam is improved.

[0057] In terms of beam-wave interaction of the planar revolving electron beam, as shown in the drawings, Figure 11 In the case of a single electron beam, the output power of the TE 01 mode is about 535kW, and the beam-wave interaction efficiency is 35%. Therefore, at 34GHz, the total output power of the two high-frequency structures is 1.070MW, which is much larger than the output power of the traditional circular revolving traveling wave tube.

[0058] Table 1

[0059]

[0060] As shown in Table 1, the Ka-band rotating emission zone multi-beam planar magnetron injection electron gun of the embodiment has a single electron emission zone area S1 = 392 mm 2 , a single electron beam current I1 = 25 A, an emission zone current density J C1 = 6.36 A / cm 2 , an electron beam area S2 = 47.1 mm 2 at the outlet, and a corresponding current density J 01 = 53.05 A / cm 2 . The conventional Ka-band outlet injection electron gun has a working current I2 = 10 A, an emission zone current density J C1 = 11.2 A / cm 2 , and an electron gun outlet current density J 01 = 78.9 A / cm 2 . In comparison, the total working current of the double electron emission zone of the present application is 50 A, which is 5 times larger, the emission zone current density is reduced to 0.56 times, the electron gun outlet current density is reduced to 0.67 times, the final electron beam speed ratio is 1.43, and the speed dispersion is 3.33%. Therefore, the present application can significantly increase the output power of the electron gun, reduce the current density of the electron beam, and reduce the space charge effect of the electron beam.

[0061] In summary, the present application can control the shaping trajectory of the planar rotating electron beam to a certain extent, reduce the speed dispersion of the shaped electron beam, thereby increasing the working current of the magnetron injection electron gun, increasing the output power of the magnetron injection electron gun, and improving the efficiency of the planar rotating wave tube. The output power of the planar magnetron injection electron gun at the present stage is 300 kW, and the efficiency is 20%. The output total power of the embodiment of the present application reaches the MW level, and the efficiency is 35%. In addition, the present application has a simple and compact structure, and has high application and promotion value.

[0062] The above examples are only for the convenience of illustrating the present application, and the present application proposes a rotating emission zone multi-beam magnetron injection electron gun structure applied to a planar rotating wave tube. In other frequency bands, it is also applicable under a larger working current, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application should be considered as equivalent replacement methods, and all are included in the protection scope of the present application.

Claims

1. A multi-beam electron gun for a planar gyrotron, comprising an anode, a cathode disposed inside the anode, and a certain distance between the anode and the cathode; characterized in that The cathode is 180-degree rotationally symmetrical about the z-axis and comprises a rear shaping pole, an emission zone, and a front shaping pole disposed in sequence along the z-axis; The rear shaping pole is a special-shaped racetrack-shaped cylinder with the same shape in any cross section along the z-axis; The special-shaped racetrack-shaped cylinder is composed of a rectangular column part, half-cylinder parts disposed on both sides of the short side of the rectangular column part, and special-shaped protrusion parts disposed on both sides of the long side of the rectangular column part, wherein the long side of the rectangular column part is parallel to the x-axis, and the short side is parallel to the y-axis;The outer side of the special-shaped protrusion part is divided into four planes connected in sequence, wherein the first plane is outwardly inclined, the second plane is a parallel plane, the third plane is outwardly inclined, and the fourth plane is a transition connecting plane; The emission zone is a racetrack-shaped structure in any cross section along the z-axis, and the size along the z-axis gradually decreases, forming an inclined emission zone;Two electron emission areas coated with an emission coating are disposed on the emission zone, the electron emission areas are elliptical and located in the central region of the xy plane projection of the special-shaped protrusion first plane to third plane, and one side close to the vertex of the special-shaped protrusion is inclined to the rear shaping pole, and the other side is inclined to the front shaping pole; The front shaping pole is a special-shaped racetrack-shaped structure in any cross section along the z-axis, and the top is chamfered to form a smooth arc surface.

2. A rotating multi-beam magnetron injection electron gun for a planar gyrotron traveling wave tube according to claim 1, wherein The distance between the midpoint of the electron emission area and the cathode axis in the x direction is d, and the projection of the transition connecting plane of the special-shaped protrusion on the x axis is 2d;The value of d is determined by the trajectory difference between the upper and lower electron beams.

3. A rotating multi-beam magnetron injection electron gun for a planar gyrotron traveling wave tube according to claim 2, wherein The emission zone is an arc surface emission zone.

4. A rotating multi-beam magnetron injection electron gun for a planar gyrotron traveling wave tube according to claim 3, wherein A rear shaping pole transition section is disposed between the rear shaping pole and the emission zone for transition connection therebetween;A front shaping pole transition section is disposed between the front shaping pole and the emission zone for transition connection therebetween.

5. A rotating multi-beam magnetron injection electron gun for a planar gyrotron traveling wave tube according to claim 4, wherein The rear shaping pole transition section is divided into an arc transition section and a linear transition section along the z-axis;The front shaping pole transition section is divided into a linear transition section and an arc transition section along the z-axis;The two-section transition can make the electric field change more smoothly and is also convenient for processing.

6. A rotating multi-beam magnetron injection electron gun for a planar gyrotron of the claim 4 or 5, characterized in that, The inclination angles of the first inclined plane and the third inclined plane of the special-shaped protrusion part are the same or different, and the projections on the x-axis have the same or different lengths;When the projection areas of the first inclined plane and the third inclined plane on the x-axis are different, the boundary positions on both sides of the parallel plane are changed to meet the electric field matching requirement.

7. A rotating multi-beam magnetron injection electron gun for a planar gyrotron traveling wave tube according to claim 6, wherein The electron emission areas are tangent to the upper and lower boundaries of the emission zone, respectively.

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