Relativistic magnetron and method for determining parameters thereof

Abstract

The present application relates to the field of microwave technology, and discloses a relativistic magnetron and a parameter determination method thereof to improve power conversion efficiency. The present application has a symmetrical structure as a whole, comprising a coaxial input structure, a resonance structure, a transition section structure and an output circular waveguide. The transition section structure is provided with outwardly protruding gradient stepped diffraction extraction cavities on the hollow circular truncated cone of the left and right end faces. Each gradient stepped diffraction extraction cavity is connected with a sector-shaped vacuum cavity, and two adjacent gradient stepped diffraction extraction cavities are separated by a sector-shaped vacuum cavity. The first outer truncated cone of the gradient stepped diffraction extraction cavity is perpendicular to the outer surface of the sector-shaped vacuum cavity and located in the same plane as the left end face of the circular truncated cone. The second outer truncated cone is parallel to the first outer truncated cone. The annular radius of the connecting part between the first outer truncated cone and the second outer truncated cone increases linearly from left to right. The circular truncated cone is provided with an extension of the sector-shaped vacuum cavity that is outwardly protruding and not connected with the gradient stepped diffraction extraction cavity.

Description

Technical Field

[0001] This invention relates to the field of microwave technology, and in particular to a relativistic magnetron and a method for determining its parameters. Background Technology

[0002] High-power microwaves refer to strong electromagnetic pulses with peak power exceeding 100MW and operating in the frequency range of 0.3 to 30GHz.

[0003] High-power microwave technology is rapidly developing, primarily involving key technologies such as primary energy technology, pulse drive source technology, high-power microwave generation technology, and high-power microwave transmission technology. Among these, high-power microwave generation technology, which converts high-power electrical pulse energy into high-power microwave energy, is the core of the entire high-power microwave technology. The relativistic magnetron, as one of the mature high-power microwave sources, possesses characteristics such as simple and compact structure, ease of fabrication, high power conversion efficiency, and the ability to operate with long-repetition-rate pulses. It plays an increasingly crucial role and occupies an increasingly important position in the field of high-power microwave sources.

[0004] The output structure of a relativistic magnetron can be divided into radial output structure and axial output structure, which are used to extract and output high-frequency field energy stored in the resonant cavity. The axial output structure can avoid the problem of high-frequency breakdown at the extraction port in the traditional radial extraction structure, and has a more stable operating mode and higher power conversion efficiency. At the same time, different numbers of diffraction extraction cavities can be used to output high-power microwaves in different modes. Currently, many scholars are using different types of extraction structures to improve the power conversion efficiency of relativistic magnetrons under different operating conditions. Summary of the Invention

[0005] The purpose of this invention is to disclose a relativistic magnetron and a method for determining its parameters, so as to improve power conversion efficiency.

[0006] To achieve the above objectives, the relativistic magnetron disclosed in this invention has a symmetrical structure, comprising, from left to right, an adjacent coaxial input structure, a resonant structure, a transition section structure, and an output circular waveguide. The coaxial input structure includes an anode shell and a cathode inner conductor. The cathode inner conductor includes a cylindrical core connected to the left cathode cap and a transmitting rod connecting the left and right cathode caps. The resonant structure includes a fan-shaped anode block and a fan-shaped vacuum cavity. The transition section structure has outwardly protruding, stepped diffraction extraction cavities on hollow truncated cones at its left and right ends. The output circular waveguide is a cylindrical structure with a radius matching the radius of the lower end face of the truncated cone. Each of the stepped diffraction extraction cavities... Each cavity is connected to a fan-shaped vacuum cavity, and two adjacent stepped diffraction extraction cavities are separated by a fan-shaped vacuum cavity. The left end face of the frustum is located between the two cathode caps to allow each of the emission rods to pass through, and the radius of the right end face is the same as the inner radius of the fan-shaped vacuum cavity. The first outer platform of the stepped diffraction extraction cavity is perpendicular to the outer surface of the fan-shaped vacuum cavity and is located on the same plane as the left end face of the frustum. The second outer platform is parallel to the first outer platform. The radius of the torus of the connecting part between the first and second outer platforms increases linearly from left to right. The frustum is provided with an outwardly protruding extension of the fan-shaped vacuum cavity that is not connected to the stepped diffraction extraction cavity.

[0007] Preferably, the number of gradient stepped diffraction extraction cavities is three.

[0008] Preferably, the fan-shaped anode block has an opening angle of 40°, and the fan-shaped vacuum cavity has an opening angle of 20°.

[0009] Preferably, the relativistic magnetron operates in the S-band, corresponding to TE. 01 The structural dimensions of the mode are as follows: the length of the coaxial input structure is 55.5 mm; the inner radius of the cylindrical anode shell is 42.6 mm; the length of the cylindrical inner core is 44 mm and the radius is 10 mm; the thickness of the two disc-shaped cathode caps is 5 mm and the radius is 18.6 mm; the length of each transmitting rod is 78 mm and the radius is 1.5 mm; in the resonant structure, the length of the sector-shaped anode block and the sector-shaped vacuum cavity is 54.5 mm, the inner radius is 22 mm, and the outer radius is 42.6 mm; the distance between the left and right end faces of the hollow frustum is 220 mm, the radius of the left end face is 22 mm, and the radius of the right end face is 87 mm; the radial height h1 of the first outer stage in the gradient stepped diffraction extraction cavity is 15 mm; the gradient angle α of the toroidal surface of the connecting part between the first and second outer stages is 13.1°; the radial height h2 of the second outer stage is 16.8 mm; the length of the output circular waveguide is 40 mm and the radius is 87 mm.

[0010] To achieve the above objectives, the present invention also discloses a method for determining the parameters of a relativistic magnetron, applied to the relativistic magnetron described above. When determining the parameters of the gradient step diffraction extraction cavity, a set of initial parameters is first determined. Then, in the simulation platform, with the optimal power conversion efficiency as the target, the optimal radius difference between the left and right end faces of the frustum is first found based on the initial parameters of the initial diffraction length. Then, the optimal diffraction length is found based on the optimal radius difference. Then, keeping the initial gradient length unchanged, the optimal gradient angle and step height between the first and second outer stage faces are found.

[0011] The present invention has the following beneficial effects:

[0012] Based on the unique gradient-step diffraction extraction cavity structure and parameter determination method of this invention, high-efficiency extraction of high-frequency field energy from the resonant cavity can be achieved; energy within the high-frequency field can be extracted and radiated as TE. 01 Microwave mode, and avoid TE 11 The mode is unstable due to uneven processing, resulting in unstable polarization direction or TE. 31 This invention addresses issues such as low mode transmission efficiency. It improves the power conversion efficiency of relativistic magnetrons under low magnetic field conditions in the S-band, enabling their application in miniaturized, high-power microwave systems such as airborne and automotive applications.

[0013] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0014] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0015] Figure 1 This is a schematic diagram of the segmented structure of the relativistic magnetron disclosed in an embodiment of the present invention.

[0016] Figure 2 This is a schematic diagram of the axial cross-section of a relativistic magnetron disclosed in an embodiment of the present invention.

[0017] Figure 3 This is a cross-sectional schematic diagram of the high-frequency resonant structure disclosed in an embodiment of the present invention.

[0018] Figure 4 This is a two-dimensional schematic diagram of a single gradient stepped diffraction extraction cavity disclosed in an embodiment of the present invention.

[0019] Figure 5 This invention discloses a method for determining the output radius r of a diffraction cavity under the condition that the transmission length ls of the diffraction cavity is constant. o A schematic diagram showing the relationship between the device output parameters.

[0020] Figure 6 The output radius r of the diffraction cavity disclosed in the embodiments of the present invention is... o A schematic diagram showing the relationship between the diffraction cavity transmission length ls and the device output parameters under certain conditions.

[0021] Figure 7 This is a schematic diagram of the simulation results disclosed in the embodiments of the present invention, which shows the influence of the gradient angle α on the output parameters of the magnetron under different values ​​of the first step height h1 of the gradient transition section while keeping the gradient length l constant.

[0022] Figure 8 This is a schematic diagram of the cross-section and electromagnetic field distribution of the transition section structure 3 disclosed in an embodiment of the present invention.

[0023] Figure 9 This is a schematic diagram of the cross-section and electromagnetic field distribution of the circular waveguide output structure 4 disclosed in an embodiment of the present invention.

[0024] Figure 10 This is a schematic diagram of the input power simulation results disclosed in an embodiment of the present invention.

[0025] Figure 11 This is a schematic diagram of the simulation results of instantaneous output power and average output power disclosed in the embodiments of the present invention.

[0026] Figure 12 This is a schematic diagram of the output microwave power spectrum simulation result disclosed in an embodiment of the present invention. Detailed Implementation

[0027] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0028] Example 1

[0029] This embodiment discloses a relativistic magnetron with a gradually increasing step-type diffraction structure, such as... Figure 1 As shown, the overall structure is symmetrical, consisting of, from left to right, an adjacent coaxial input structure 1, a resonant structure 2, a transition section structure 3, and an output circular waveguide 4.

[0030] The coaxial input structure includes an anode shell and a cathode inner conductor. The cathode inner conductor includes a cylindrical inner core connected to the left cathode cap and an emission rod connected between the left and right cathode caps.

[0031] The resonant structure includes a sector-shaped anode block and a sector-shaped vacuum cavity.

[0032] The transition section structure has outwardly protruding stepped diffraction extraction cavities on hollow circular platforms at both ends. The output circular waveguide is a cylindrical structure with a radius consistent with the radius of the lower end face of the circular platform. Each stepped diffraction extraction cavity is connected to a fan-shaped vacuum cavity, and a fan-shaped vacuum cavity separates two adjacent stepped diffraction extraction cavities. The left end face of the circular platform is located between two cathode caps to allow each of the transmitting rods to pass through, and the radius of the right end face is consistent with the inner radius of the fan-shaped vacuum cavity. The first outer platform of the stepped diffraction extraction cavity is perpendicular to the outer surface of the fan-shaped vacuum cavity and is located on the same plane as the left end face of the circular platform. The second outer platform is parallel to the first outer platform. The radius of the torus of the connecting part between the first and second outer platform increases linearly from left to right. The circular platform has an outwardly protruding extension of the fan-shaped vacuum cavity that is not connected to the stepped diffraction extraction cavity.

[0033] A schematic diagram of the axial cross-section of a compact relativistic magnetron with high-efficiency output in a specific S-band TE01 mode is shown below. Figure 2 As shown, the coaxial input structure 1 includes a cylindrical anode shell 1-1 with a length of 55.5 mm and an inner radius of 42.6 mm, and a cathode inner conductor 1-2. The cathode inner conductor 1-2 includes a cylindrical inner core 1-2-1 with a length of 44 mm and a radius of 10 mm, a left disc-shaped cathode cap 1-2-2 with a thickness of 5 mm and a radius of 18.6 mm, three emission rods 1-2-3 with a length of 78 mm and a radius of 1.5 mm, and a right disc-shaped cathode cap 1-2-4 with a thickness of 5 mm and a radius of 18.6 mm. The cross-section of the high-frequency resonant structure is shown below. Figure 3 As shown, the high-frequency resonant structure 2 includes six angles θ. a =40° sector-shaped anode block 2-1 and six opening angles θ c The fan-shaped vacuum cavity 2-2 has a radius of 20°. The length of the fan-shaped anode block 2-1 and the fan-shaped vacuum cavity 2-2 are 54.5 mm, the inner radius is 22 mm, and the outer radius is 42.6 mm. The transition section structure 3 includes a hollow frustum 3-1 and three gradually stepped diffraction extraction cavities 3-2. The distance between the left and right end faces of the hollow frustum 3-1 is 220 mm, the radius of the left end face is 22 mm, and the radius of the right end face is 87 mm. The first section of the three gradually stepped diffraction extraction cavities 3-2 has a radial height h1 of 15 mm and a gradient angle α = 13.1°. The second section has a radial height h2 of 16.8 mm. The three gradually stepped diffraction extraction cavities 3-2 are connected to the fan-shaped vacuum cavity 2-2 in the high-frequency resonant structure 2 and are symmetrically distributed with one fan-shaped vacuum cavity 2-2 between them. The circular waveband output structure 4 consists of a cylinder 4-1 with a length of 40 mm and a radius of 87 mm.

[0034] A two-dimensional schematic diagram of a single gradient stepped diffraction extraction cavity in this embodiment is shown below. Figure 4As shown, it mainly consists of a first radial height h1, a gradient angle α, a second radial height h2, and a tilt angle β. Among these, the tilt angle β, the first step height h1, the gradient angle α, and the second radial height h2 are crucial factors for improving the device's power conversion efficiency. First, the tilt angle β of the diffraction extraction cavity needs to be determined, as the tilt angle β of the diffraction extraction cavity is related to the diffraction length ls and the output radius r. o Related; Figure 5 This demonstrates that, under the condition that the transmission length ls of the diffraction cavity is constant, the output radius r of the diffraction cavity is... o The relationship between the device's output parameters and the output radius is analyzed through simulation to optimize the output radius r. o =87mm; Figure 6 This demonstrates the output radius r of the diffraction cavity. o Under certain conditions, the relationship between the diffraction cavity transmission length ls and the device output parameters was analyzed through simulation to optimize the transmission length, which was determined to be ls = 220 mm. Therefore, the tilt angle β = 21.6° can be determined.

[0035] The key structure in this embodiment is the gradually changing stepped structure composed of a first radial height h1, a gradient angle α, and a second radial height h2. Keeping the gradient length l constant, the influence of the gradient angle α on the magnetron output parameters is analyzed under different values ​​of the first step height h1 of the gradually changing stepped transition section. Figure 7 As shown in the simulation results, when the gradient length l remains constant, the gradient angle α required for the device to achieve optimal conversion efficiency decreases as the height of the first step h1 increases. When the device achieves optimal conversion efficiency, the height of the first step in the gradient transition section is h1 = 15 mm, the gradient angle α = 13.1°, and the height of the second step is h2 = 16.8 mm.

[0036] In this embodiment, the gradient step-type diffraction extraction cavities 3-2-1, 3-2-2, and 3-2-3 are distributed at 120° intervals to extract high-frequency field energy. The cross-section and electromagnetic field distribution of the transition section structure 3 are as follows. Figure 8 As shown, the cross-section and electromagnetic field distribution of the circular waveguide output structure 4 are as follows. Figure 9 As shown, it can be observed that the microwave energy in transition section structure 3 is gradually converted into the TE in circular waveguide output structure 4. 01 mold.

[0037] Electromagnetic particle simulation calculations performed according to the above structure show that the relativistic magnetron of this embodiment has an output power of 218MW, a power conversion efficiency of 71%, an operating frequency of 2.375GHz, and an output mode of TE under the conditions of operating voltage of 220kV and magnetic field of 0.25T. 01The model is relatively pure, and the simulation results of the input power are as follows: Figure 10 As shown, the simulation results for instantaneous output power and average output power are as follows: Figure 11 As shown, the simulation results of the output microwave power spectrum are as follows: Figure 12 As shown.

[0038] Example 2

[0039] Corresponding to the above embodiments, this embodiment discloses a method for determining the parameters of a relativistic magnetron, applied to the relativistic magnetron described in the above embodiments. When determining the parameters of the gradient step diffraction extraction cavity, a set of initial parameters is first determined. Then, in the simulation platform, with the goal of optimal power conversion efficiency, the optimal radius difference between the left and right end faces of the frustum is first found based on the initial parameters of the initial diffraction length. Then, the optimal diffraction length is found based on the optimal radius difference. Then, keeping the initial gradient length unchanged, the optimal gradient angle and step height between the first outer stage and the second outer stage are found.

[0040] In summary, the relativistic magnetrons and their parameter determination methods disclosed in the embodiments of this invention, based on the unique graded-step diffraction extraction cavity structure and parameter determination method of this invention, can achieve high-efficiency extraction of high-frequency field energy from the resonant cavity; they can extract energy within the high-frequency field and radiate TE. 01 Microwave mode, and avoid TE 11 The mode is unstable due to uneven processing, resulting in unstable polarization direction or TE. 31 This invention addresses issues such as low mode transmission efficiency. It improves the power conversion efficiency of relativistic magnetrons under low magnetic field conditions in the S-band, enabling their application in miniaturized, high-power microwave systems such as airborne and automotive applications.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A relativistic magnetron, characterized in that, The overall structure is symmetrical, consisting of, from left to right, adjacent coaxial input structures, resonant structures, transition sections, and output circular waveguides. The coaxial input structure includes an anode shell and a cathode inner conductor. The cathode inner conductor includes a cylindrical core connected to the left cathode cap and a transmitting rod connecting the left and right cathode caps. The resonant structure includes a fan-shaped anode block and a fan-shaped vacuum cavity. The transition section structure has outwardly protruding, stepped diffraction extraction cavities on hollow circular truncated cones at its left and right ends. The output circular waveguide is a cylindrical structure with a radius matching the radius of the lower end face of the circular truncated cone. Each stepped diffraction extraction cavity is connected to a fan-shaped vacuum cavity. The cavities are interconnected, and a fan-shaped vacuum cavity separates two adjacent stepped diffraction extraction cavities. The left end face of the frustum is located between the two cathode caps to allow each of the emission rods to pass through, and the radius of the right end face is the same as the inner radius of the fan-shaped vacuum cavity. The first outer platform of the stepped diffraction extraction cavity is perpendicular to the outer surface of the fan-shaped vacuum cavity and is located on the same plane as the left end face of the frustum. The second outer platform is parallel to the first outer platform. The radius of the torus of the connecting part between the first and second outer platforms increases linearly from left to right. The frustum is provided with an outwardly protruding extension of the fan-shaped vacuum cavity that is not connected to the stepped diffraction extraction cavity.

2. The relativistic magnetron according to claim 1, characterized in that, The number of gradient stepped diffraction extraction cavities is three.

3. The relativistic magnetron according to claim 2, characterized in that, The fan-shaped anode block has an opening angle of 40°, and the fan-shaped vacuum cavity has an opening angle of 20°.

4. The relativistic magnetron according to any one of claims 1 to 3, characterized in that, The relativistic magnetron operates in the S-band, corresponding to the TE band. 01 The structural dimensions of the patterns are as follows: The coaxial input structure is 55.5 mm long, the cylindrical anode shell has an inner radius of 42.6 mm, the cylindrical inner core is 44 mm long and has a radius of 10 mm; the two disc-shaped cathode caps on the left and right are each 5 mm thick and have a radius of 18.6 mm; each emission rod is 78 mm long and has a radius of 1.5 mm. In the resonant structure, the length of the sector-shaped anode block and the sector-shaped vacuum cavity are 54.5 mm, the inner radius is 22 mm, and the outer radius is 42.6 mm. The distance between the left and right end faces of the hollow frustum is 220mm, the radius of the left end face is 22mm, the radius of the right end face is 87mm, the radial height h1 of the first outer stage in the gradient stepped diffraction extraction cavity is 15mm, the gradient angle α of the toroidal surface of the connecting part between the first and second outer stages is 13.1°, and the radial height h2 of the second outer stage is 16.8mm. The output circular waveguide has a length of 40mm and a radius of 87mm.

5. A method for determining the parameters of a relativistic magnetron, applied to a relativistic magnetron as described in any one of claims 1 to 4, characterized in that, When determining the parameters of the gradient stepped diffraction extraction cavity, a set of initial parameters is first determined. Then, in the simulation platform, with the optimal power conversion efficiency as the target, the optimal radius difference between the left and right end faces of the frustum is first found based on the initial parameters of the initial diffraction length. Then, the optimal diffraction length is found based on the optimal radius difference. Then, keeping the initial gradient length unchanged, the optimal gradient angle and step height between the first outer stage and the second outer stage are found.

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