Angularly tuned frequency agile relativistic magnetron

Abstract

This invention discloses an angularly tuned, frequency-agile relativistic magnetron, belonging to the field of high-power microwave source technology. The magnetron includes first and second anode cylinders coaxial along the axial direction and with the same inner radius. A cathode structure is located inside the anode cylinder, and a radial extraction structure that mates with the anode cylinder is located on the outer side. The inner wall of the first anode cylinder has several small fan-shaped tuning blades, and the second anode cylinder has a large fan-shaped fixed blade with a fitting groove. The fixed blade extends into the first anode cylinder, and the fitting groove matches the tuning blade. The tuning blade rotates angularly with the first anode cylinder and embeds into the fixed blade, forming a dynamically variable anode blade. This invention achieves broadband continuous tuning of the operating frequency by rotating the first anode cylinder angularly to drive the tuning blade, thereby changing the equivalent radius and equivalent angle of the resonant cavity. It satisfies the requirement for broadband tuning while maintaining a compact and lightweight magnetron design.

Description

Technical Field

[0001] This invention belongs to the field of high-power microwave source technology, and particularly relates to an angularly tuned, frequency-agile relativistic magnetron. Background Technology

[0002] The book "High-power microwave" points out that, from the perspective of developing practical high-power microwave systems, future high-power microwave sources will develop in four directions: compactness and lightweight; long lifespan; continuous or pulse repetition frequency operation; and broadband tuning.

[0003] Since its invention in the last century, the relativistic magnetron has received widespread attention as a stable, broadband-tunable high-power microwave source. Initially, most high-power microwave sources, including the relativistic magnetron, were designed to operate only at a single frequency. As the applications of high-power microwave technology have expanded to multiple dimensions, the inherent limitations of its single-frequency operation mode have become a key factor restricting the further development of this technology. Currently, many researchers are dedicated to solving the application requirements of achieving broadband continuous tuning of high-power microwave sources in a compact form. The frequency-agile relativistic magnetron is a high-power microwave source that can achieve rapid broadband continuous tuning at its operating frequency.

[0004] Currently, the most mature frequency-agile relativistic magnetron tuning methods are mainly mechanical tuning, which can be divided into axial tuning and radial tuning based on the direction of motion of the tuning structure. In technical route 1, by adjusting the axial length of the coupling slot of the relativistic magnetron, a tuning bandwidth of 1.23 GHz to 1.7 GHz was achieved, with a maximum in-band output power of 1.8 GW and a maximum efficiency of 54% (see "F. Qin, Y. Zhang, S. Xu, L.-R. Lei, B.-Q. Ju and D. Wang, 'A Frequency-Agile Relativistic Magnetron With Axial Tuning,' in IEEE Electron Device Letters"). In technical route 2, a tuning bandwidth of 1.28 GHz to 2.43 GHz was achieved by adjusting the anode radius of the relativistic magnetron, with a maximum conversion efficiency of 72% (see "Kunpeng Chen, HaodongXu, Zeyang Liu, Yuwei Fan; "A high-efficiency tunable relativistic magnetron with diffraction output, ". in AIP Advances 1.").

[0005] From a working principle perspective, the operating frequency of a relativistic magnetron is closely related to the resonant frequency of its interaction region resonant cavity. Changing the resonant frequency within a certain range will result in a corresponding change in its operating frequency. Furthermore, as an orthogonal field device, the relativistic magnetron requires a constant axial magnetic field to maintain the angular cyclotron motion of electrons within the interaction region. Therefore, the size of the interaction region directly affects the design dimensions of the external magnetic field mechanism. In particular, increasing the radial dimension of the interaction region significantly increases the design difficulty and manufacturing cost of the external magnetic field mechanism. This also means that when designing a compact and lightweight relativistic magnetron, the adaptability of the external magnetic field structure must be considered simultaneously. Moreover, in cylindrical coordinates, the resonant frequency of the resonant cavity is affected not only by changes in radial and axial dimensions but also by changes in angular dimensions. Currently, research on angularly tuned frequency-agile relativistic magnetrons is still relatively scarce. Summary of the Invention

[0006] To address the issue that existing frequency-agile relativistic magnetrons mostly employ axial and radial tuning methods, which easily alter the radial / axial dimensions of the interaction region, increasing the design difficulty of the external magnetic field mechanism and making it difficult to simultaneously meet the requirements of compactness, lightweight design, and wideband tuning, this invention provides an angularly tuned frequency-agile relativistic magnetron. This invention innovatively improves the resonant cavity structure, employing angular tuning to achieve wideband continuous tuning while retaining the original compactness and lightweight characteristics of the relativistic magnetron. It successfully achieves wideband frequency agility on a compact basis, adapting to the development requirements of practical high-power microwave systems.

[0007] The technical solution adopted in this invention is as follows:

[0008] An angularly tuned frequency-agile relativistic magnetron includes a first anode cylinder and a second anode cylinder arranged coaxially along the axial direction and having the same inner radius, a cathode structure arranged along the anode axis, and a radial extraction structure that cooperates with the first anode cylinder and the second anode cylinder.

[0009] The inner wall of the first anode cylinder is uniformly distributed with N small fan-shaped tuning blades along the circumference, where N is an even number not less than 4;

[0010] The second anode cylinder is provided with N large fan-shaped fixed blades with fitting grooves; the fixed blades extend into the first anode cylinder, and the fitting grooves match the shape of the tuning blades;

[0011] The tuning blade can rotate angularly with the first anode cylinder, so that the tuning blade is embedded in the fixed blade; the tuning blade and the fixed blade form a dynamically variable anode blade, thereby changing the equivalent radius and equivalent angle of the resonant cavity between adjacent fixed blades, and realizing broadband continuous tuning of the relativistic magnetron operating frequency.

[0012] Preferably, the radial extraction structure includes N coupling seams, a vacuum chamber shell, N / 2 insert plates, and a sealing assembly;

[0013] Among them, N coupling seams are evenly distributed on the second anode cylinder;

[0014] The outer shell of the vacuum chamber is coaxially disposed outside the first anode cylinder and the second anode cylinder, forming an annular columnar vacuum chamber;

[0015] A sealing assembly is provided between the vacuum chamber shell and the first anode cylinder, and the vacuum chamber shell and the first anode cylinder can rotate relative to each other at an angle; the sealing assembly is used to ensure the airtightness of the vacuum chamber;

[0016] N / 2 of the aforementioned insert plates are evenly distributed along the circumference at the front end of the vacuum chamber, dividing the front end of the vacuum chamber into N / 2 fan-shaped waveguide cavities;

[0017] Two adjacent coupling seams correspond to a sector waveguide cavity on their outer sides. Microwave energy is radially extracted to the sector waveguide cavity through the coupling seams and then combined into a single output in the coaxial cavity at the rear end of the vacuum chamber.

[0018] Preferably, the maximum angle of rotation of the first anode cylinder is 6°-12°.

[0019] Preferably, the sealing assembly is a fluororubber sealing ring or a magnetohydrodynamic sealing assembly.

[0020] Preferably, the cathode structure includes a cathode support rod, an upstream cathode end cap, a cathode emitter, and a downstream cathode end cap arranged coaxially and sequentially.

[0021] The beneficial effects of this invention are as follows:

[0022] The relativistic magnetron provided by this invention employs an angular tuning method. By angularly rotating the first anode cylinder, the tuning blades are moved, altering the equivalent radius and equivalent angle of the relativistic magnetron's internal resonant cavity. This causes corresponding changes in the cavity's equivalent electrical parameters (equivalent inductance and equivalent capacitance), thereby achieving broadband continuous tuning of the magnetron's operating frequency. This invention fills a gap in current research on angularly tuned relativistic magnetrons and addresses previous shortcomings in understanding and practice within related technologies. Furthermore, the angular tuning method does not alter the magnetron's radial and axial dimensions, thus not affecting the design dimensions of the external magnetic field mechanism. It maximizes the compactness and lightweight characteristics of the relativistic magnetron at a single frequency point, eliminating the need for additional structures and successfully achieving broadband frequency agility in a compact relativistic magnetron, meeting the development needs of practical high-power microwave systems. Attached Figure Description

[0023] Figure 1 This is a cross-sectional view of the angularly tuned, frequency-agile relativistic magnetron of the present invention.

[0024] Figure 2 This is a schematic diagram of the angularly tuned, frequency-agile relativistic magnetron of the present invention when the rotation angle is 0°;

[0025] Figure 3 This is a schematic diagram of the angularly tuned, frequency-agile relativistic magnetron of the present invention when the rotation angle is 12°;

[0026] Figure 4 This is a schematic cross-sectional view of the angularly tuned, agile, relativistic magnetron of the present invention after removing the radial extraction structure;

[0027] Figure 5 This is a schematic diagram of the output end of the radial extraction structure of the angularly tuned, frequency-agile relativistic magnetron of the present invention;

[0028] Figure 6 This is a simulation result curve of the angularly tuned agile relativistic magnetron of the present invention when it rotates from 0° to 8°.

[0029] Explanation of reference numerals in the attached drawings: 11. First anode cylinder; 12. Second anode cylinder; 13. Tuning blade; 14. Fixed blade; 15. Fitting groove; 21. Coupling seam; 22. Vacuum chamber shell; 23. Insert plate; 24. Fluororubber sealing ring; 25. Coaxial output section; 31. Cathode support rod; 32. Upstream cathode end cap; 33. Cathode emitter; 34. Downstream cathode end cap. Detailed Implementation

[0030] To make the objectives, technical solutions, and problems solved by this invention clearer, the invention will be further described quantitatively below with reference to the accompanying drawings and specific examples. The following examples are merely illustrative of the invention and do not limit its scope.

[0031] This example provides an angularly tuned, frequency-agile relativistic magnetron operating in the X-band, such as... Figures 1-5 As shown, the relativistic magnetron includes a first anode cylinder and a second anode cylinder, both with a diameter of 38 mm, arranged coaxially along the axial direction, a cathode structure arranged along the anode axis, and a radial extraction structure that cooperates with the first anode cylinder and the second anode cylinder.

[0032] The inner wall of the first anode cylinder has eight small fan-shaped tuning blades of the same size evenly distributed along the circumference; the tuning blades are 35mm long, have an inner radius of 16.5mm, and have a corresponding central angle of 15°.

[0033] The second anode cylinder is provided with eight large fan-shaped fixed blades with fitting grooves. The fixed blades are 40mm long, have an inner radius of 14mm, and a corresponding central angle of 20°. The fixed blades extend into the first anode cylinder, and the fitting grooves match the shape of the tuning blades.

[0034] The tuning blade can rotate angularly with the first anode cylinder, so that the tuning blade is completely embedded in the fixed blade; the tuning blade and the fixed blade form a dynamically variable anode blade, thereby changing the equivalent radius and equivalent angle of the resonant cavity between adjacent fixed blades, and realizing broadband continuous tuning of the relativistic magnetron operating frequency.

[0035] The radial extraction structure includes eight coupling seams, a vacuum chamber shell, four insert plates, and a sealing assembly.

[0036] The eight coupling seams are evenly distributed on the second anode cylinder and located between adjacent fixed blades; the length of the coupling seam is 18 mm and the central angle corresponding to the seam width is 25°.

[0037] The outer shell of the vacuum chamber is coaxially disposed outside the first anode cylinder and the second anode cylinder, forming an annular cylindrical vacuum chamber with an inner radius of 22 mm and an outer radius of 24 mm.

[0038] A fluororubber sealing ring is provided between the outer shell of the vacuum chamber and the first anode cylinder to ensure the airtightness of the vacuum chamber.

[0039] Four 50 mm long insert plates are evenly distributed around the front of the vacuum chamber, dividing the front of the vacuum chamber into four fan-shaped waveguide cavities with a central angle of 70°.

[0040] Two adjacent coupling seams correspond to a fan-shaped waveguide cavity on their outer sides. Microwave energy is radially extracted to the fan-shaped waveguide cavity through the coupling seams and then combined into a single output in the coaxial output section at the rear end of the vacuum chamber.

[0041] The cathode structure includes a cathode support rod, an upstream cathode end cap, a cathode emitter, and a downstream cathode end cap arranged coaxially and sequentially; wherein, the cathode support rod is a metal rod with a radius of 3 mm, the cathode emitter is a graphite ring with an outer radius of 5 mm and an inner radius of 3 mm, and the cathode end cap is a metal cylinder with an inner radius of 3 mm, a thickness of 4 mm, and rounded corners on both sides.

[0042] The angularly tuned, frequency-agile relativistic magnetron provided in this embodiment employs an angular tuning method, adjusting the anode blades from 0° to 8° by angular rotation. Figure 6 As shown, the tuning range is from 7.75 GHz to 8.33 GHz, the output power within the band is greater than 600 MW, and the maximum conversion efficiency is 47%.

Claims

1. An angularly tuned frequency agile relativistic magnetron, characterized in that, It includes a first anode cylinder and a second anode cylinder arranged coaxially along the axial direction and having the same inner radius, a cathode structure arranged along the anode axis, and a radial extraction structure that cooperates with the first anode cylinder and the second anode cylinder; The inner wall of the first anode cylinder is uniformly distributed with N small fan-shaped tuning blades along the circumference, where N is an even number not less than 4. The second anode cylinder is provided with N large fan-shaped fixed blades with fitting grooves; the fixed blades extend into the first anode cylinder, and the fitting grooves match the shape of the tuning blades; The tuning blade can rotate angularly with the first anode cylinder, so that the tuning blade is embedded in the fixed blade; The tuning blades and fixed blades form dynamically variable anode blades, thereby changing the equivalent radius and equivalent angle of the resonant cavity between adjacent fixed blades, and realizing broadband continuous tuning of the relativistic magnetron's operating frequency.

2. A corner tuned tunable relativistic magnetron as defined in claim 1, characterized in that, The radial extraction structure includes N coupling seams, a vacuum chamber shell, N / 2 insert plates, and a sealing assembly; Among them, N coupling seams are evenly distributed on the second anode cylinder; The outer shell of the vacuum chamber is coaxially disposed outside the first anode cylinder and the second anode cylinder, forming an annular columnar vacuum chamber; A sealing assembly is provided between the vacuum chamber shell and the first anode cylinder, and the vacuum chamber shell and the first anode cylinder can rotate relative to each other at an angle; the sealing assembly is used to ensure the airtightness of the vacuum chamber; N / 2 of the aforementioned insert plates are evenly distributed along the circumference at the front end of the vacuum chamber, dividing the front end of the vacuum chamber into N / 2 fan-shaped waveguide cavities; Two adjacent coupling seams correspond to a sector waveguide cavity on their outer sides. Microwave energy is radially extracted to the sector waveguide cavity through the coupling seams and then combined into a single output in the coaxial cavity at the rear end of the vacuum chamber.

3. A corner tuned tunable relativistic magnetron as defined in claim 2, characterized in that, The maximum angular rotation angle of the first anode cylinder is 6°-12°.

4. The angularly tuned, frequency-agile relativistic magnetron as described in claim 3, characterized in that, The sealing assembly is a fluororubber sealing ring or a magnetohydrodynamic sealing assembly.

5. An angularly tuned, frequency-agile, relativistic magnetron as described in claim 3 or 4, characterized in that, The cathode structure includes a cathode support rod, an upstream cathode end cap, a cathode emitter, and a downstream cathode end cap arranged coaxially and sequentially.

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