Relativistic magnetron for angular slotting coupling output

Abstract

The invention discloses a relativistic magnetron with angular slotting coupling output, the magnetron adopts a radial extraction rectangular output structure, the magnetron comprises an anode, a cathode and a magnet, the anode comprises a long anode block and a short anode block, the end part of the short anode block is provided with an angular coupling slot, the end part of the long anode block is provided with a reflection ring, and the end part of the short anode block is provided with an angular coupling slot. A high-frequency magnetic field is distributed in a fan-shaped cavity formed among the short anode block, the long anode block and the reflecting ring, and the high-frequency magnetic field is coupled into an external waveguide through the angular coupling slot to realize output; according to the relativistic magnetron disclosed by the invention, the adopted output structure is positioned at the end part of the anode block, and all the resonant cavities participate in microwave energy extraction, so that the angular periodic symmetry of the resonant cavities is hardly influenced by the output structure; and the coupling output structure and the output structure are axially separated from the resonant cavity area, the external space of the resonant cavity can be used for arranging magnets, the excitation space is small, and the realization of light and small size of the system is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of high-power microwaves, and in particular to a relativistic magnetron with angular slot coupling output. Background Art

[0002] High Power Microwave (HPM) refers to electromagnetic waves with a peak power greater than 100MW and a frequency between 1GHz and 300GHz. It is an interdisciplinary research field that has developed since the 1970s with the development of pulse power technology, relativistic electronics, and plasma physics. High-power microwave sources are devices that mainly use relativistic electron beams to generate high-power microwave radiation and are one of the key components in high-power microwave systems.

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

[0004] In the early days, relativistic magnetrons used a radial output structure, which coupled microwave energy through an axial slot on the outer wall of the resonant cavity. Since this output structure occupies the radial space outside the resonant cavity, it is impossible to arrange magnets in this area. In order to ensure that a uniform axial guide magnetic field is provided to the resonant cavity, a pair of Helmholtz coils or permanent magnets must be arranged at both ends of the resonant cavity. This excitation system is too large and does not meet the requirements of system miniaturization. In addition, due to the breakdown threshold limit of a single coupling slot, the output efficiency is low.

[0005] In 2006, Greenwood, Hoff and others proposed a full-cavity extraction axial output structure, which can be regarded as an improvement of the traditional radial output structure. This structure connects the coupling slits of adjacent resonant cavities to a fan-shaped output waveguide in a symmetrical 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 output waveguide and transmitted axially. Compared with the traditional radial output structure, the full-cavity extraction axial output structure has periodic symmetry and has little effect on the working state of the magnetron; and microwaves are transmitted axially, and the periphery of the fan-shaped waveguide can still be used to lay out magnets, which has a certain improvement in compactness compared to the traditional radial output structure. However, due to the existence of the fan-shaped output waveguide outside the resonant cavity, the lateral size of the entire system is still larger than the outer radius of the anode, resulting in a larger inner diameter of the magnet, and the level of system miniaturization is still limited. Summary of the invention

[0006] In view of the shortcomings of the existing technology, a relativistic magnetron with angular slit coupled output is proposed, which solves the problem of the existence of a fan-shaped output waveguide outside the resonant cavity in the prior art. The lateral dimension of the entire system is still large compared with the outer radius of the anode, resulting in a large inner diameter of the magnet and the system's miniaturization level is still limited.

[0007] To achieve the above objectives, the present invention proposes the following technologies to achieve the above objectives: A relativistic magnetron with angular slot coupling output, the magnetron adopts a radial extraction rectangular output structure, and the magnetron comprises an anode, a cathode and a magnet; The anode includes a long anode block and a short anode block, an angular coupling slot is provided at the end of the short anode block, a reflection ring is provided at the end of the long anode block, a high-frequency magnetic field is distributed in the fan-shaped cavity formed between the short anode block, the long anode block and the reflection ring, and the high-frequency magnetic field is coupled into an external waveguide through the angular coupling slot to realize output.

[0008] Furthermore, the fan-shaped cavity is located at one end of the short anode block close to the reflective ring, the fan-shaped cavity is located inside the outer cylinder, and the angular coupling slot is opened on the outer cylinder and connected to the fan-shaped cavity.

[0009] Furthermore, the long anode block and the short anode block are respectively located inside the outer cylinder, and one end of the long anode block away from the fan-shaped cavity is flush with one end of the short anode block away from the fan-shaped cavity.

[0010] Furthermore, the number of the long anode blocks and the number of the short anode blocks are respectively n, n is not less than 2, and the n long anode blocks and the n short anode blocks are evenly distributed along the circumference of the inner wall of the outer cylinder.

[0011] Furthermore, the long anode blocks and the short anode blocks are alternately arranged on the inner wall of the outer cylinder, gaps are arranged between adjacent long anode blocks and short anode blocks to form a resonance cavity, and the fan-shaped cavity is located between two adjacent long anode blocks.

[0012] Furthermore, the reflection ring is fixed on the inner wall of the outer cylinder, the outer diameter of the reflection ring is equal to the inner diameter of the outer cylinder, and the end of the long anode block abuts against the reflection ring.

[0013] Furthermore, the waveguide includes a fan-shaped transition waveguide connected to the fan-shaped cavity, and the fan-shaped transition waveguide is located outside the outer cylinder to facilitate output of the high-frequency magnetic field in the fan-shaped cavity.

[0014] Furthermore, the waveguide also includes a rectangular output waveguide arranged at the end of the fan-shaped transition waveguide, and the output end of the rectangular output waveguide is arranged parallel to the axis of the outer cylinder.

[0015] Furthermore, the cathode is located inside the outer cylinder and is coaxially arranged with the outer cylinder, and the anode and the reflection ring are respectively arranged around the cathode.

[0016] Furthermore, the magnet includes a first magnet and a second magnet which are sleeved on the periphery of the outer cylinder, and the first magnet and the second magnet are respectively arranged on both sides of the fan-shaped transition waveguide.

[0017] Compared with the prior art, the comprehensive effects brought by the present invention include: (1) In the relativistic magnetron of the present invention, since the output structure is located at the end of the anode block and all the resonant cavities participate in microwave energy extraction, the angular periodic symmetry of the resonant cavity is almost unaffected by the output structure; the coupled output structure and the output structure are axially separated from the resonant cavity area, and the external space of the resonant cavity can be used to arrange the magnet, and the excitation space is small, which is conducive to realizing the lightweight and miniaturization of the system.

[0018] (2) In the present application, multiple output waveguides are provided, and multiple equal-phase rectangular waveguide fundamental mode electromagnetic waves are output, which is convenient for feeding into array antennas such as waveguide slot arrays for direct radiation. This structure has the characteristics of large output power, high conversion efficiency, compact system, easy combination and output with waveguide slot array antennas, and easy miniaturization of permanent magnet packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall external structure of an embodiment of the present invention; Figure 2 It is a schematic diagram of the overall internal structure of an embodiment of the present invention; Figure 3 This is a schematic diagram of the anode and cathode installation positions of an embodiment of the present invention; Figure 4 This is a schematic diagram of the distribution structure of long anode blocks and short anode blocks in an embodiment of the present invention; Figure 5 This is a schematic diagram of the connection structure between the angular coupling slot and the waveguide according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the magnetic field distribution structure of a magnet according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the electric field distribution of the output port of an embodiment of the present invention; Figure 8 This is a schematic diagram of the magnetic field distribution of the output port of an embodiment of the present invention; Fig. 9 is a total output power signal diagram of an embodiment of the present invention; Fig.10 Output microwave spectrum diagram for the embodiment of the present invention.

[0020] Legend: 1. Outer cylinder; 2. Long anode block; 3. Short anode block; 4. Reflection ring; 5. Cathode; 6. First magnet; 7. Angular coupling slot; 8. Fan-shaped transition waveguide; 9. Rectangular output waveguide; 10. Second magnet. DETAILED DESCRIPTION

[0021] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the protection scope of the present invention.

[0022] In this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. The orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "top", etc. is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0023] like Figures 1 to 10 As shown, a relativistic magnetron with angular slot coupling output, the magnetron adopts a radial extraction rectangular output structure, and the magnetron includes an anode, a cathode 5 and a magnet; The anode includes a long anode block 2 and a short anode block 3, an angular coupling slot 7 is provided at the end of the short anode block 3, a reflection ring 4 is provided at the end of the long anode block 2, a high-frequency magnetic field is distributed in the fan-shaped cavity formed among the short anode block 3, the long anode block 2 and the reflection ring 4, and the high-frequency magnetic field is coupled into the external waveguide through the angular coupling slot 7 to realize output.

[0024] The relativistic magnetron of the present invention has an output structure located at the end of the anode block, and all the resonant cavities between the long anode blocks 2 and the short anode blocks 3 participate in microwave energy extraction, so that the angular periodic symmetry of the resonant cavity is almost unaffected by the output structure; the coupled output structure and the output structure are axially separated from the resonant cavity area, and the outer space of the resonant cavity can be used to arrange the magnet, and the excitation space is small, which is conducive to realizing the lightweight and miniaturization of the system; multiple equal-phase rectangular waveguide fundamental mode electromagnetic wave outputs are arranged to facilitate feeding into array antennas such as waveguide slot arrays for direct radiation.

[0025] Specifically, the anode is made of non-magnetic stainless steel, titanium alloy and other materials; the magnet is a permanent magnet made of hard magnetic material or an electromagnetic coil according to actual needs; the cathode 5 base material is non-magnetic stainless steel, titanium alloy and other materials, and the cathode 5 emission material is set at a certain position according to needs to emit electrons, and the emission material can be graphite, velvet and the like.

[0026] In the relativistic magnetron with angular slot coupled output of this embodiment, the fan-shaped cavity is located at one end of the short anode block 3 close to the reflection ring 4, the fan-shaped cavity is located inside the outer cylinder 1, and the angular coupling slot 7 is opened on the outer cylinder 1 and connected to the fan-shaped cavity.

[0027] Specifically, the long anode block 2 and the short anode block 3 are respectively located inside the outer cylinder 1 , and one end of the long anode block 2 away from the fan-shaped cavity is flush with one end of the short anode block 3 away from the fan-shaped cavity.

[0028] Through the above arrangement, the ends of the long anode block 2 and the short anode block 3 close to the reflection ring 4 are of different lengths, thereby leaving space to form a fan-shaped cavity and facilitating the opening of an angular coupling slit 7 on the outer cylinder 1 .

[0029] By arranging anode blocks of alternating lengths and shorts, a resonant cavity is formed between the long anode block 2 and the short anode block 3 to generate electromagnetic waves. At the same time, an angular coupling slot 7 is opened on the fan-shaped cavity opened by the length difference of the anode block, so that the electromagnetic waves are output from the angular coupling slot 7. At the same time, the radius of the magnet is reduced, so that the distance between the magnet and the resonant cavity is reduced. Compared with the currently available commonly used magnetrons, the radius of the magnet is much larger than the radius of the resonant cavity, resulting in a heavier magnet and a larger excitation space.

[0030] The present application mainly moves the output port to the downstream of the anode terminal, and the wide side of the output waveguide is distributed along the angular direction, and the narrow side is distributed along the axial direction. In this way, the inner radius of the magnet can be reduced to the outer radius of the resonant cavity, thereby reducing the size of the magnet and facilitating the realization of lightness and miniaturization; and the magnet is moved to the interaction area where the axial magnetic field needs to be provided, so that the excitation space is basically equal to the cylindrical space with a radius equal to the radius of the resonant cavity.

[0031] In the angular slot coupled output relativistic magnetron of this embodiment, n long anode blocks 2 and n short anode blocks 3 are respectively provided, n is not less than 2, and the n long anode blocks 2 and n short anode blocks 3 are evenly distributed along the circumference of the inner wall of the outer tube 1.

[0032] In the relativistic magnetron with angular slot coupled output of this embodiment, the long anode blocks 2 and the short anode blocks 3 are alternately arranged on the inner wall of the outer tube 1, and gaps are provided between adjacent long anode blocks 2 and short anode blocks 3 to form a resonant cavity, and the fan-shaped cavity is located between two adjacent long anode blocks 2.

[0033] When the magnetron operates in π mode, there is a 180° phase difference between the electric field and the magnetic field of adjacent resonant cavities; according to the continuity of the magnetic field, two adjacent axial magnetic fields with a phase difference of 180° form an angular magnetic field at both ends of the anode block; that is, there is an angularly distributed high-frequency magnetic field in the n fan-shaped cavities composed of the short anode block 3, the long anode block 2, and the reflection ring 4, and the high-frequency magnetic field is coupled into the waveguide through the angular coupling slot 7 to achieve output.

[0034] In the relativistic magnetron with angular slot coupled output of this embodiment, the waveguide includes a fan-shaped transition waveguide 8 connected to the fan-shaped cavity, and the fan-shaped transition waveguide 8 is located outside the outer cylinder 1 to facilitate the output of the high-frequency magnetic field in the fan-shaped cavity. The waveguide also includes a rectangular output waveguide 9 arranged at the end of the fan-shaped transition waveguide 8, and the output end of the rectangular output waveguide 9 is parallel to the axis of the outer cylinder.

[0035] Specifically, the high-frequency magnetic field is coupled into the fan-shaped transition waveguide 8 through the angular coupling slot 7, and excites a TE10-like mode in the fan-shaped transition waveguide 8, and then enters the rectangular output waveguide 9 to be converted into a TE10 mode and further output outward; the n TE10 mode electromagnetic waves are equal in amplitude and phase.

[0036] In the relativistic magnetron with angular slot coupled output of the present embodiment, the reflection ring 4 is fixed on the inner wall of the outer cylinder 1, the outer diameter of the reflection ring 4 is equal to the inner diameter of the outer cylinder 1, the end of the long anode block 2 is against the reflection ring 4, the cathode 5 is located inside the outer cylinder 1 and is coaxially arranged with the outer cylinder 1, and the anode and the reflection ring 4 are respectively arranged around the cathode 5; the magnet includes a first magnet 6 and a second magnet 10 which are sleeved on the periphery of the outer cylinder 1, and the first magnet 6 and the second magnet 10 are respectively arranged on both sides of the fan-shaped transition waveguide 8.

[0037] A reflection ring 4 is arranged at one side of the sector-shaped cavity and connected to the end of the long anode block 2 to reflect the electromagnetic waves moving from the resonant cavity into the sector-shaped cavity, thereby enhancing the high-frequency magnetic field in the sector-shaped cavity and further enhancing the coupling output capability.

[0038] This embodiment is an A6 type angular slot coupled output relativistic magnetron, such as Figure 2 As shown, six anode blocks are arranged, uniformly surrounding the outer periphery of the cathode 5 along the angular direction, close to the anode outer tube 1, and forming six resonant cavities. There are three long anode blocks 2, with an inner radius of 33.3mm, an outer radius of 60mm, an axial length of 92mm, and an opening angle of 40°; there are three short anode blocks 3, with an inner radius of 33.3mm, an outer radius of 60mm, an axial length of 68mm, and an opening angle of 40°; the six anode blocks are alternately distributed in length and short and aligned at one end. The reflection ring 4 is located at the end of the long anode block 2 and is connected to the long anode block 2, with an outer radius of 60mm, an inner radius of 44mm, and an axial thickness of 6mm. As shown Figure 4 and Figure 5As shown, the short anode block 3, the long anode block 2 and the reflective ring 4 form three fan-shaped cavities with an opening angle of 80° at the end of the outer tube 1. The cathode 5 is a transparent cathode, which consists of three parts, namely, a cathode bottom column, an end cap, and three metal columns of the same size. The cathode bottom column is a cylinder with a radius of 15.8mm and a length of 80mm; the cathode end caps are two cylinders with a radius of 25.8mm and a thickness of 20mm; the cross-sections of the three metal columns are all fan-shaped columns with an inner radius of 10mm, an outer radius of 15.8mm, and an angle of 40°. The length of the metal column is 77mm. There are three angular coupling slits 7, which are respectively located on the side walls of the three fan-shaped cavities with an opening angle of 80° at the end of the short anode block 3, and on the common wall connecting the three 80° fan-shaped cavities and the three fan-shaped transition waveguides 8. The inner radius of the angular coupling slit 7 is 60mm, the outer radius is 68mm, the opening angle is 80°, and the axial length is 20mm. There are three fan-shaped transition waveguides 8, the inner radius of the fan-shaped waveguide 8 is 68mm, the outer radius is 90.5mm, the opening angle is 85°, and the axial length of the fan-shaped transition waveguide 8 is 32mm. The three rectangular output waveguides 9 radially connected to the three fan-shaped transition waveguides 8 have a wide side of 110mm, a narrow side of 32mm, and a length of 80m. The permanent magnet is divided into three sections, and the material is selected from N48sh neodymium iron boron with a remanence of 1.4T and a coercive force of 1.1146e6 (A / m), and the inner radius is 63mm; the first magnet 6 includes: the leftmost permanent magnet is radially magnetized, the outer radius is 123mm, and the axial length is 45mm; the middle section permanent magnet is axially magnetized, the outer radius is 73mm, and the axial length is 100mm; the second magnet 10 includes: the rightmost permanent magnet is radially magnetized, the outer radius is 108mm, and the axial length is 140mm.

[0039] The particle simulation software is used to calculate the output relativistic magnetron with angular slot coupling output under the above structural dimensions under the conditions of feed voltage of about 610 kV and guide magnetic field of about 0.34 T. The results are as follows Fig. 9 He Ru Fig.10 As shown: an L-band microwave output with a resonant frequency of 1.832 GHz, an output power of 1.82 GW, and a power conversion efficiency of 50.4% was obtained. The total weight of the magnet in this embodiment is about 42.36 kg. This shows that the invention can maintain a relatively high beam conversion efficiency under low guide magnetic field conditions and can be applied to high-power microwave systems with strict requirements for lightness and miniaturization.

[0040] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "rotation" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0041] Although the embodiments of the present invention have been shown and described in detail, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A relativistic magnetron with angular slot coupled output, characterized in that: The magnetron adopts a radial extraction rectangular output structure, and the magnetron includes an anode, a cathode and a magnet; The anode includes a long anode block and a short anode block, an angular coupling slot is provided at the end of the short anode block, a reflection ring is provided at the end of the long anode block, a high-frequency magnetic field is distributed in the fan-shaped cavity formed between the short anode block, the long anode block and the reflection ring, and the high-frequency magnetic field is coupled into an external waveguide through the angular coupling slot to realize output.

2. A relativistic magnetron with angular slot coupling output according to claim 1, characterized in that: The fan-shaped cavity is located at one end of the short anode block close to the reflective ring, the fan-shaped cavity is located inside the outer cylinder, and the angular coupling slot is opened on the outer cylinder and connected to the fan-shaped cavity.

3. The relativistic magnetron with angular slot coupling output according to claim 2, characterized in that: The long anode block and the short anode block are respectively located inside the outer cylinder, and one end of the long anode block away from the fan-shaped cavity is flush with the other end of the short anode block away from the fan-shaped cavity.

4. The relativistic magnetron with angular slot coupled output according to claim 3, characterized in that: The number of the long anode blocks and the number of the short anode blocks are respectively n, n is not less than 2, and the n long anode blocks and the n short anode blocks are evenly distributed along the circumference of the inner wall of the outer cylinder.

5. The relativistic magnetron with angular slot coupling output according to claim 4, characterized in that: The long anode blocks and the short anode blocks are alternately arranged on the inner wall of the outer cylinder, gaps are arranged between adjacent long anode blocks and short anode blocks to form a resonance cavity, and the fan-shaped cavity is located between two adjacent long anode blocks.

6. The relativistic magnetron with angular slot coupling output according to claim 2, characterized in that: The reflection ring is fixed on the inner wall of the outer cylinder, the outer diameter of the reflection ring is equal to the inner diameter of the outer cylinder, and the end of the long anode block abuts against the reflection ring.

7. The relativistic magnetron with angular slot coupling output according to claim 2, characterized in that: The waveguide comprises a fan-shaped transition waveguide connected to the fan-shaped cavity, and the fan-shaped transition waveguide is located outside the outer cylinder so as to output the high-frequency magnetic field in the fan-shaped cavity.

8. The relativistic magnetron with angular slot coupling output according to claim 7, characterized in that: The waveguide further comprises a rectangular output waveguide arranged at the end of the fan-shaped transition waveguide, and the output end of the rectangular output waveguide is arranged parallel to the axis of the outer cylinder.

9. The relativistic magnetron with angular slot coupling output according to claim 2, characterized in that: The cathode is located inside the outer cylinder and is coaxially arranged with the outer cylinder, and the anode and the reflection ring are arranged around the cathode respectively.

10. The relativistic magnetron with angular slot coupling output according to claim 7, characterized in that: The magnet comprises a first magnet and a second magnet which are sleeved on the periphery of the outer cylinder, and the first magnet and the second magnet are respectively arranged on two sides of the fan-shaped transition waveguide.

Images