Relativistic magnetron for full-cavity extraction and radial output

Abstract

The utility model relates to a relativistic magnetron for full-cavity extraction and radial output, which belongs to the technical field of high-power microwaves and comprises an anode, a cathode and a magnet, the anode comprises an anode block and an anode shell, a fan-shaped waveguide and a rectangular waveguide are arranged on the periphery of the anode shell, and the rectangular waveguide is arranged along the radial direction of the anode shell. The fan-shaped waveguide is provided with two short-circuit surfaces along the axial direction of the anode shell, one end part of the rectangular waveguide is connected with one short-circuit surface of the fan-shaped waveguide, and the technical problems in the prior art that the periodic symmetry of an interaction region is poor, the inner diameter of the magnet is larger, and the light and small size cannot be realized can be solved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of high power microwave technology, concretely relates to a full cavity extraction radial output relativistic magnetron. BACKGROUND

[0002] High power microwave (HPM) refers to electromagnetic wave with peak power greater than 100 MW and frequency between 1 GHz and 300 GHz, which is a cross research field developed since the 1970s along with the development of pulse power technology, relativistic electronics and plasma physics. High power microwave source is a device for generating high power microwave radiation by using relativistic electron beam, and is one of key components in high power microwave system.

[0003] Relativistic magnetron (RM) has the advantages of simple structure, low operating magnetic field, high power and repeated pulse working capacity, and is one of the most practical high power microwave sources with small size. At present, the research focus of relativistic magnetron is to improve power and conversion efficiency, reduce the volume and weight of the whole system, and realize the design of small size. Among them, the output structure is a key factor affecting the small size.

[0004] The early relativistic magnetron adopts radial output structure, and the microwave energy is coupled out along the axial direction by slits on the outer wall of a resonant cavity. Since the output structure occupies the radial outer space of the resonant cavity, the region cannot be arranged with magnets. In order to ensure that the resonant cavity has a uniform axial guiding magnetic field, a pair of Helmholtz coils or permanent magnets must be arranged at both ends of the resonant cavity. However, compared with the single magnet system arranged directly in the radial outer space of the resonant cavity, the magnet system is more complex. Due to the existence of a single coupling slit, the periodic symmetry of the interaction region is poor, which affects the stability of the magnetron; and due to the limitation of the breakdown threshold of the slit, the output efficiency is low.

[0005] In 2006, Greenwood and Hoff proposed a full cavity extraction axial output structure, which can be regarded as an improvement of the traditional radial output structure. The structure connects the coupling slits of adjacent resonant cavities with a fan-shaped rectangular waveguide in a symmetric form along the center line. When the working mode of the magnetron is π mode, the TE11 mode will be excited in the fan-shaped rectangular waveguide and transmitted along the axial direction. Compared with the traditional radial output structure, the full cavity extraction axial output structure has periodic symmetry and less influence on the working state of the magnetron; and the microwave is transmitted along the axial direction, so the periphery of the fan-shaped waveguide can still be used to arrange magnets, and the magnet structure is simplified compared with the traditional radial output structure. However, due to the existence of the fan-shaped rectangular waveguide in the periphery of the resonant cavity, the transverse size of the whole system is still larger than the outer radius of the anode, which leads to a larger inner diameter of the magnet, and the level of light and small size of the system is still limited. Utility Model Content

[0006] To address the shortcomings of existing technologies, a relativistic magnetron with full-cavity radial output extraction is proposed to solve the technical problems of poor periodic symmetry in the interaction region, large internal diameter of the magnet, and inability to achieve miniaturization in existing technologies.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A relativistic magnetron with full cavity extraction radial output includes an anode, a cathode, and a magnet. The anode includes an anode block and an anode shell. A fan-shaped waveguide and a rectangular waveguide are disposed around the periphery of the anode shell. The rectangular waveguide is arranged radially along the anode shell. The fan-shaped waveguide has two short surfaces along the axial direction of the anode shell. One end of the rectangular waveguide is connected to one of the short surfaces of the fan-shaped waveguide.

[0009] The technical solution is further configured such that the anode shell is cylindrical, and several anode blocks are periodically distributed along the angular direction of the anode shell, with the cavity between adjacent anode blocks forming a resonant cavity.

[0010] The technical solution is further configured such that the number of anode blocks is 2N, where N is a positive integer not less than 2, and the number of resonant cavities is equal to the number of anode blocks.

[0011] The technical solution is further configured such that an axial coupling slit is formed on the cavity wall of the resonant cavity, extending along the axial direction of the anode shell. The number of axial coupling slits is equal to the number of resonant cavities, and all axial coupling slits are periodically distributed along the angular direction of the anode shell.

[0012] The technical solution is further configured such that the two axial coupling seams located in adjacent resonant cavities are connected to the same sector waveguide in a manner symmetrical about the central axis of the anode shell.

[0013] The technical solution is further configured such that a waveguide coupling slot is provided at the junction of the fan-shaped waveguide and the rectangular waveguide, and the length of the waveguide coupling slot is not greater than the width of the rectangular waveguide.

[0014] The technical solution is further configured such that the magnet is disposed on the periphery of the anode shell, and the inner diameter of the magnet is equal to the outer diameter of the anode shell.

[0015] The technical solution is further configured such that the magnet adopts a two-segment combined structure, and the two magnet segments are respectively located on both sides of the fan-shaped waveguide.

[0016] The technical solution is further configured such that the magnet is a permanent magnet or an electromagnet.

[0017] The cathode comprises a bottom column, a connecting rod and end caps, the bottom column is coaxially arranged with the anode shell, the end caps are provided in two and symmetrically arranged at two ends of the connecting rod.

[0018] The present application has the following beneficial effects:

[0019] The rectangular waveguide is arranged along the radial direction of the anode shell, one end of the rectangular waveguide is connected with one short circuit surface of the fan-shaped waveguide, all the resonance cavities participate in microwave energy extraction, the angular periodic symmetry of the resonance cavities is hardly affected by the output structure, meanwhile, the axial length of the fan-shaped waveguide is shortened, the magnet can be arranged on both sides of the fan-shaped waveguide, which is beneficial to realize miniaturization, multi-path equal-phase rectangular waveguide fundamental mode electromagnetic wave output, which is convenient for feeding into waveguide slot array and direct radiation, and is beneficial to reduce the axial size of the magnetron. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a side view of the relativistic magnetron with full-cavity extraction and radial output according to the embodiment of the present application;

[0021] Figure 2 It is a side view of the relativistic magnetron with full-cavity extraction and radial output according to the embodiment of the present application;

[0022] Figure 3 It is a front view of the relativistic magnetron with full-cavity extraction and radial output according to the embodiment of the present application; Figure 2 It is an A-A sectional view according to the embodiment of the present application;

[0023] Figure 4 It is a front view of the relativistic magnetron with full-cavity extraction and radial output according to the embodiment of the present application;

[0024] Figure 5 It is a B-B sectional view according to the embodiment of the present application; Figure 4 It is a B-B sectional view according to the embodiment of the present application;

[0025] Figure 6 It is a schematic view of the cathode according to the embodiment of the present application;

[0026] Figure 7 It is a C-C sectional view according to the embodiment of the present application; Figure 6 It is a C-C sectional view according to the embodiment of the present application;

[0027] Figure 8 It is a schematic view of the total output power signal according to the embodiment of the present application;

[0028] Figure 9 It is a schematic view of the output microwave frequency spectrum according to the embodiment of the present application.

[0029] In the drawings: 1, anode shell; 2, rectangular waveguide; 3, magnet; 4, anode block; 5, resonance cavity; 6, fan-shaped waveguide; 7, waveguide coupling slot; 8, bottom column; 9, end cap; 10, connecting rod. DETAILED DESCRIPTION

[0030] In order to make the technical scheme of the utility model better understood by the people in the art, the technical scheme of the utility model will be described clearly and completely below in combination with the drawings of the utility model, based on the embodiments in the present application, other similar embodiments obtained by the people in the art without making creative efforts should belong to the scope of protection of the present application. In addition, the directional words mentioned in the following embodiments, such as 'up', 'down', 'left', 'right', etc. are only the directions of the drawings, therefore, the directional words used are used to explain but not to limit the utility model.

[0031] According to the utility model embodiments, a kind of cavity extraction radial output's relativistic magnetron is provided, please refer to Figures 1 to 7 , including anode, cathode and magnet 3, the anode includes anode block 4 and anode shell 1, the periphery of the anode shell 1 is provided with fan-shaped waveguide 6 and rectangular waveguide 2, the rectangular waveguide 2 is along the radial of anode shell 1 and is provided, the fan-shaped waveguide 6 has two short-circuit surfaces along the axial direction of anode shell 1, and one end of the rectangular waveguide 2 is connected with one short-circuit surface of the fan-shaped waveguide 6.

[0032] Preferably, the anode is made of non-magnetic stainless steel, titanium alloy or other materials;Magnet 3 is made of permanent magnet or electromagnetic coil according to actual needs;The base material of the cathode is non-magnetic stainless steel, titanium alloy or other materials, and the cathode emission material is arranged at a certain position according to needs to emit electrons, and the emission material can be graphite, velvet, etc.

[0033] It should be noted that the rectangular waveguide 2 is arranged along the radial direction of the anode shell 1, and one end of the rectangular waveguide 2 is connected with one short-circuit surface of the fan-shaped waveguide 6, all the resonant cavities 5 participate in microwave energy extraction, the angular periodic symmetry of the resonant cavity 5 is almost not affected by the output structure, at the same time, the axial length of the fan-shaped waveguide 6 is shortened, and the magnet 3 can be arranged on both sides of the fan-shaped waveguide 6, which is conducive to realizing miniaturization;Multi-path equal-phase rectangular waveguide fundamental mode electromagnetic wave output is convenient for feeding into waveguide slot array antenna for direct radiation, which is conducive to reducing the axial size of the magnetron.

[0034] In the present embodiment, the cavity extraction radial output's relativistic magnetron is provided, please refer to Figures 1 to 7 , the anode shell 1 is set as a cylindrical shape, and the anode block 4 is periodically distributed along the angular direction of the anode shell 1, and the cavity between the adjacent anode blocks 4 constitutes a resonant cavity 5.

[0035] Specifically, the number of the anode blocks 4 is 2N, N is a positive integer not less than 2, the 2N anode blocks 4 are uniformly arranged around the central axis of the anode shell 1, and the 2N anode blocks 4 form 2N resonant cavities 5, that is, the number of the resonant cavities 5 is equal to the number of the anode blocks 4.

[0036] In the full-cavity extraction radial output relativistic magnetron of the embodiment, please refer to Figures 1 to 7 The cavity wall of the resonant cavity 5 is provided with an axial coupling slot extending along the axial direction of the anode shell 1, the number of the axial coupling slots is equal to the number of the resonant cavities 5, and all the axial coupling slots are periodically distributed along the angular direction of the anode shell 1.

[0037] It should be noted that the cavity wall of each resonant cavity 5 is provided with an axial coupling slot, the axial coupling slots extend along the axial direction of the anode shell 1, and a total of 2N axial coupling slots are provided on the 2N resonant cavities 5, and the 2N axial coupling slots are uniformly arranged around the central axis of the anode shell 1.

[0038] In the full-cavity extraction radial output relativistic magnetron of the embodiment, please refer to Figures 1 to 7 The two axial coupling slots of adjacent resonant cavities 5 are connected to the same sector waveguide 6 in a symmetrical manner with respect to the central axis of the anode shell 1.

[0039] It should be noted that the two adjacent axial coupling slots are connected to the same sector waveguide 6, and N sector waveguides 6 are required for the 2N axial coupling slots.

[0040] In the full-cavity extraction radial output relativistic magnetron of the embodiment, please refer to Figures 1 to 7 The sector waveguide 6 is provided with a waveguide coupling slot 7 at the joint with the rectangular waveguide 2, and the length of the waveguide coupling slot 7 is not greater than the length of the wide side of the rectangular waveguide 2.

[0041] Specifically, in the embodiment, the wide side of the rectangular waveguide 2 is aligned with the right end short-circuit surface of the sector waveguide 6, and along the angular direction of the anode shell 1, the rectangular waveguide 2 and the sector waveguide 6 are distributed one by one, that is, N sector waveguides 6 correspond to N rectangular waveguides 2, and N waveguide coupling slots 7 are arranged at the connection between the N rectangular waveguides 2 and the N sector waveguides 6. The 2N axial coupling slots sequentially couple the energy in the resonant cavities 5 to the N sector waveguides 6 and the N rectangular waveguides 2 in the radial direction, and the output direction of the rectangular waveguide 2 is parallel to the central axis of the anode shell 1.

[0042] In the full-cavity extraction radial output relativistic magnetron of the embodiment, please refer to Figures 1 to 7 The magnet 3 is arranged on the periphery of the anode shell 1, and the inner diameter of the magnet 3 is equal to the outer diameter of the anode shell 1.

[0043] Specifically, the magnet 3 adopts a two-segment combined structure, and the two segments of the magnet 3 are located at two sides of the fan-shaped waveguide 6.

[0044] It should be noted that the radial coupling extraction structure of the rectangular waveguide 2 shortens the axial length of the fan-shaped waveguide 6, the magnet 3 can be arranged at two sides of the fan-shaped waveguide 6, the radius of the magnet 3 is equal to the outer diameter of the anode shell 1, and the magnet 3 is beneficial to realize the miniaturization of the system.

[0045] In the full-cavity extraction radial output relativistic magnetron of the embodiment, the cathode comprises a bottom column 8, a connecting rod 10 and end caps 9, the bottom column 8 is coaxially arranged with the anode shell 1, and the end caps 9 are symmetrically arranged at two ends of the connecting rod 10. Figures 1 to 7

[0046] Preferably, the cathode emission material is arranged between the two end caps 9.

[0047] The working principle of the full-cavity extraction radial output relativistic magnetron is as follows: when the magnetron works in a π mode, there is a 180° phase difference between electric fields and magnetic fields between adjacent resonant cavities 5; adjacent resonant cavities 5 excite fan-shaped TE11 modes in corresponding fan-shaped waveguides 6 through axial coupling slots, then excite rectangular waveguide 2 TE10 modes further to output outward through waveguide coupling slots 7 at right end short-circuit surfaces of the fan-shaped waveguides 6; N-way TE10 mode electromagnetic waves are in phase and have the same amplitude. Specific embodiments:

[0049] 6 anode blocks 4 are uniformly circumferentially arranged at the periphery of the cathode and closely contact the anode shell 1 to form 6 resonant cavities 5. The inner radius of the anode block 4 is 32 mm, the outer radius is 60 mm, the axial length is 80 mm, and the opening angle is 40°; the length of the axial coupling slot is 53 mm, and the angle is 20°.

[0050] The cathode is a transparent cathode and comprises three parts, namely, a bottom column 8, end caps 9 and six same-size cylinders (as connecting rods 10); the bottom column 8 is a cylinder with a radius of 15 mm and a length of 80 mm; the end caps 9 are two cylinders with a radius of 24 mm and a thickness of 20 mm; the six cylinders all have a cross-section radius of 5 mm and a length of 120 mm, of which only three emit, and the emission area has a length of 50 mm.

[0051] There are three waveguide coupling slots 7, which are respectively located on the common walls of the three 85° fan-shaped waveguides 6 and the three rectangular waveguides 2; the width of the waveguide coupling slot 7 is 16 mm, and the length thereof is equal to the length of the wide side of the rectangular waveguide 2.

[0052] ​The three sector waveguides 6 have an inner radius of 68 mm, an outer radius of 91 mm, an opening angle of 85°, and an axial length of 94 mm. The three rectangular waveguides 2 radially connected to the three sector waveguides 6 have a width of 110 mm, a narrow side length of 32 mm, and a radial length of 80 mm.

[0053] The magnet 3 is composed of two segments with a distance of 100 mm, and the material is selected as a residual magnetism of 1.4T neodymium iron boron, and the inner radius is 63 mm; both of the two segments are radially magnetized, and the outer radius is 109 mm, and the axial length is 82 mm.

[0054] The particle simulation software is used to calculate the relativistic magnetron with the full cavity extraction radial output under the structure size, the feeding voltage is about 630kV, and the guide magnetic field is about 0.36T, and the results are as shown in Figure 8 and as Figure 9 shown: the L-band microwave output with a resonance frequency of 1.556GHz, an output power of 1.8GW, and a power conversion efficiency of 56.7% is obtained, and the total weight of the magnet is about 32.04kg, which shows that the utility model can maintain a relatively high beam-wave conversion efficiency under the condition of a lower guide magnetic field, and can be applied to a high-power microwave system with strict requirements on light and miniaturization.

[0055] The utility model has been described in detail above, and the above is only a preferred embodiment of the utility model, and cannot limit the utility model implementation range, that is, all equivalent changes and modifications made according to the application range should still belong to the utility model coverage.

Claims

1. A full cavity extraction radial output relativistic magnetron comprising an anode, a cathode and a magnet, the anode comprising an anode block and an anode housing, the periphery of the anode housing being provided with a sectorial waveguide and a rectangular waveguide, characterized in that, The rectangular waveguide is arranged along the radial direction of the anode shell, the sector waveguide has two short-circuit surfaces along the axial direction of the anode shell, and one end of the rectangular waveguide is connected to one short-circuit surface of the sector waveguide. The anode blocks are periodically arranged along the angular direction of the anode shell, and the cavities between adjacent anode blocks form resonant cavities, and the cavity walls of the resonant cavities are provided with axial coupling slots extending along the axial direction of the anode shell.

2. A full interaction extraction radial output relativistic magnetron according to claim 1, characterized in that, The anode shell is in the shape of a cylinder.

3. A full interaction extraction radial output relativistic magnetron according to claim 2, characterized in that, The number of the anode blocks is 2N, N is a positive integer not less than 2, and the number of the resonant cavities is equal to the number of the anode blocks.

4. A full- cavity extraction radial output relativistic magnetron according to claim 2 or 3, characterized in that, The number of the axial coupling slots is equal to the number of the resonant cavities, and all the axial coupling slots are periodically arranged along the angular direction of the anode shell.

5. A full interaction extraction radial output relativistic magnetron according to claim 4, characterized in that, Two axial coupling slots of adjacent resonant cavities are symmetrically connected to the same sector waveguide along the central axis of the anode shell.

6. A full- cavity extracted relativistic magnetron for radial output according to claim 1, characterized in that, The sector waveguide is provided with a waveguide coupling slot at the joint with the rectangular waveguide, and the length of the waveguide coupling slot is not greater than the length of the wide side of the rectangular waveguide.

7. A full- cavity extraction, radial output, relativistic magnetron according to claim 1, wherein, The magnet is arranged at the periphery of the anode shell, and the inner diameter of the magnet is equal to the outer diameter of the anode shell.

8. A full interaction extraction radial output relativistic magnetron according to claim 7, characterized in that, The magnet has a two-segment combined structure, and the two segments of the magnet are arranged on the two sides of the sector waveguide.

9. A full- wave extraction radial output relativistic magnetron according to claim 7 or 8, characterized in that, The magnet is a permanent magnet or an electromagnet.

10. A full- cavity extraction, radially output, relativistic magnetron according to claim 1, characterized in that, The cathode comprises a bottom column, a connecting rod and end caps, the bottom column is coaxially arranged with the anode shell, and two end caps are symmetrically arranged at the two ends of the connecting rod.

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