Coaxial magnetron with externally loaded metamaterial

Abstract

This invention discloses a coaxial magnetron with an externally loaded metamaterial, comprising, from the inside out, an anode blade assembly, an anode cylinder, a metamaterial layer, and an outer cylinder. The anode blade assembly consists of multiple anode blades arranged in a uniform ring array, with adjacent anode blades forming a resonant inner cavity. The anode cylinder is fitted outside the anode blade assembly, and its wall has multiple coupling slots. The anode cylinder and the outer cylinder form a coaxial outer cavity, and the inner and outer cavities are connected and communicate with each other through the coupling slots. The metamaterial layer is disposed between the anode cylinder and the outer cylinder to connect the two. The metamaterial layer consists of multiple metamaterial units arranged in a ring array, and each metamaterial unit is a copper sheet with a hollow dumbbell pattern. This invention improves the compactness of the coaxial magnetron while ensuring efficiency, suppresses the competitive mode of the coaxial magnetron, and enhances the anode heat dissipation performance of the coaxial magnetron.

Description

Technical Field

[0001] This invention relates to vacuum electronic devices, and more specifically to a coaxial magnetron with an external cavity loaded with metamaterial. Background Technology

[0002] As a re-entrant resonant quadrature field oscillator, the magnetron is an important high-power source in the field of microwave technology. It possesses significant advantages such as high efficiency, compact structure, and low cost, making it one of the most widely used high-power microwave electronic devices. Currently, the applications of magnetrons have gradually expanded to microwave heating, biomedical therapy, industrial non-destructive testing, and materials processing, demonstrating broad technological adaptability and market potential.

[0003] During operation, a mutually perpendicular DC electric field and a DC magnetic field are simultaneously applied inside the magnetron. Electrons interact with the high-frequency microwave signal under the combined influence of these two fields, converting the energy gained from the DC electric field into high-frequency microwave energy output. However, traditional magnetrons often face mode degeneracy problems, where multiple resonant modes have the same or similar resonant frequencies, easily leading to mode competition and output instability. Among these, the π mode (with a phase shift of 180° between adjacent resonant cavities) has high stability due to the absence of degenerate modes, making it the preferred operating mode for magnetrons.

[0004] Based on their working principles and structural forms, magnetrons can be classified into several types, including coaxial magnetrons and heterocavity magnetrons. Coaxial magnetrons, as one common type, add a coaxial external cavity to the traditional resonant cavity system (internal cavity), forming a dual-cavity resonant structure. Typically, the internal cavity operates in the π mode, while the external cavity operates in the TE mode. 011 Mode control. In this structure, the inner cavity typically handles about 10% of the total energy, while the outer cavity handles about 90%. This distribution effectively improves overall efficiency and frequency stability. Coaxial magnetrons, through their unique mode control mechanism, have significant advantages in improving frequency stability and efficiency. However, their structure also has certain limitations: the introduction of the outer cavity usually results in a larger device size, and similar to traditional magnetrons, their heat dissipation performance is often poor. This, to some extent, restricts their application in certain high-power, high-integration scenarios. Summary of the Invention

[0005] The purpose of this invention is to propose a coaxial magnetron with an external cavity loaded with metamaterial.

[0006] The technical solution for achieving the objective of this invention is: a coaxial magnetron with an externally loaded metamaterial, comprising, from the inside out, an anode blade assembly, an anode cylinder, a metamaterial layer, and an outer cylinder, wherein:

[0007] The anode blade group is composed of multiple anode blades arranged in a uniform ring array, with adjacent anode blades forming a resonant cavity.

[0008] The anode cylinder is sleeved outside the anode blade assembly, and multiple coupling gaps are opened on its cylinder wall. The anode cylinder and the outer cylinder form a coaxial outer cavity, and the inner cavity and the outer cavity are connected and communicate with each other through the coupling gaps.

[0009] The metamaterial layer is disposed between the anode cylinder and the outer cylinder to connect the two; the metamaterial layer is composed of multiple metamaterial units arranged in a ring array, and the metamaterial unit is a metal copper sheet with a hollow dumbbell pattern.

[0010] Furthermore, the anode blade assembly includes 28 anode blades, each anode blade being 5.96 mm long, 1.78 mm wide, and 8.2 mm high.

[0011] Furthermore, the anode cylinder has a thickness of 1.5 mm, a height of 23.1 mm, and a diameter of 35.68 mm.

[0012] Furthermore, there are 14 coupling gaps arranged in a uniform ring array; each coupling gap has a height of 20.1 mm, a width of 0.8 mm, and is located in the middle of the two anode blades.

[0013] Furthermore, the outer cylinder has a diameter of 71mm, a height of 22mm, and a thickness of 1.5mm.

[0014] Furthermore, the thickness of the metamaterial unit is 0.5 mm; the total length of the hollow dumbbell pattern is 15 mm, the gap in the middle is 1.2 mm, and the diameter of the circular parts at both ends is 5.6 mm; the metamaterial units are arranged in a uniform ring array with an interval angle of 15°.

[0015] Furthermore, the metamaterial layer has a resonant peak at a frequency of 9.2 GHz, which is used to suppress the competing modes of the coaxial magnetron.

[0016] Furthermore, the metamaterial layer is made of metallic copper to improve the heat dissipation performance of the anode cylinder.

[0017] Compared with existing technologies, the significant advantages of this invention are as follows: by introducing a metallic metamaterial layer between the anode cylinder and the outer cylinder, the structure is miniaturized and its performance optimized. This metamaterial structure can effectively regulate the electromagnetic field distribution and suppress non-operating modes (especially competing modes), thereby enhancing mode purity and output stability. Simultaneously, the introduced metamaterial possesses excellent thermal conductivity, which can significantly improve the heat dissipation capacity of the device, contributing to improved reliability and lifespan of the magnetron under high-power operating conditions. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of the coaxial magnetron with external cavity loading metamaterial of the present invention.

[0019] Figure 2 This is a top view of the coaxial magnetron with external cavity loading metamaterial of the present invention.

[0020] Figure 3 This is a schematic diagram of the metamaterial unit of the present invention and its S-parameters.

[0021] Figure 4 This is the electric field distribution diagram of the coaxial magnetron of the present invention.

[0022] Figure 5 This is a temperature comparison chart of electrothermal combined simulation between the structure of this invention and the structure without metamaterials. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0024] like Figure 1 , 2 As shown, the coaxial magnetron with the metamaterial loaded in the outer cavity consists of an anode blade assembly 1, an anode cylinder 2, a metamaterial layer 3, and an outer cylinder 4.

[0025] Anode blade assembly 1 is located in the middle of anode cylinder 2. Each anode blade has the following dimensions: length 5.96 mm, width 1.78 mm, and height 8.2 mm. There are 28 anode blades in total, arranged in a uniform ring array. Adjacent anode blades form a resonant cavity.

[0026] The anode cylinder 2 has the following dimensions: thickness 1.5 mm, height 23.1 mm, and diameter 35.68 mm. Coupling slots 5 are formed on the cylinder wall. Each coupling slot has a height of 20.1 mm and a width of 0.8 mm. These coupling slots are located at the midpoint between every two anode blades and are arranged in a uniform ring array, totaling 14 slots. These coupling slots 5 serve as energy channels between the inner and outer cavities.

[0027] The outer cylinder 4 has the following dimensions: diameter 71mm, height 22mm, and thickness 1.5mm. The anode cylinder 2 and the outer cylinder 4 form a coaxial external cavity.

[0028] Metamaterial layer 3 is located precisely between the anode cylinder 2 and the outer cylinder 4, serving to connect the two. The metamaterial layer consists of multiple independent units, each unit being a piece of copper metal with a hollowed-out dumbbell pattern, its specific shape as shown in the image. Figure 3 As shown. The specific parameters of each metamaterial unit are: thickness 0.5 mm, total length of the dumbbell pattern 15 mm, spacing between the patterns 1.2 mm, and diameter of the circular portions at both ends of the pattern 5.6 mm. These metamaterial units are uniformly arranged in a ring array with a 15° interval. The electromagnetic properties of the metamaterial structure exhibit a distinct resonance peak at a frequency of 9.2 GHz.

[0029] The electric field distribution of the π-mode of the coaxial magnetron structure of this invention is as follows: Figure 4 As shown, the electric field phase difference between adjacent cavities is π. The operating frequency of the π mode is 9.28 GHz, the frequency of the π±1 mode is 9.56 GHz, and the mode isolation is 0.28 GHz. Compared with the conventional structure without metamaterial loading (whose π±1 mode frequency is 9.35 GHz), this invention improves the mode isolation by 0.21 GHz. Simultaneously, the π mode Q value of this structure is as high as 8624.

[0030] Its thermodynamic diagram was obtained through electrothermal coupling simulation and compared with the structure without metamaterial loading. Figure 5 As shown, this invention can reduce the anode temperature by 200°C. Compared with traditional coaxial magnetrons of the same type, this invention can reduce the outer diameter of the coaxial magnetron by 35% and improve heat dissipation performance by 31%.

[0031] In summary, this invention integrates a specially designed metamaterial into the outer cavity and utilizes the metamaterial's resonance capability with electromagnetic fields to achieve frequency selection of the coaxial magnetron's outer cavity within a smaller volume, suppressing the competing modes of the coaxial magnetron. At the same time, by leveraging the metamaterial's excellent thermal conductivity and metallic properties, the anode heat dissipation performance of the coaxial magnetron is improved.

[0032] The embodiments described above merely illustrate the implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A coaxial magnetron with an externally loaded metamaterial, characterized in that, It includes, from the inside out, an anode blade assembly (1), an anode cylinder (2), a metamaterial layer (3), and an outer cylinder (4), wherein: The anode blade group (1) is composed of multiple anode blades arranged in a uniform ring array, with adjacent anode blades forming a resonant cavity; The anode cylinder (2) is sleeved outside the anode blade assembly (1), and multiple coupling gaps (5) are provided on its cylinder wall. The anode cylinder (2) and the outer cylinder (4) form a coaxial outer cavity, and the inner cavity and the outer cavity are connected and communicated through the coupling gaps (5). The metamaterial layer (3) is disposed between the anode cylinder (2) and the outer cylinder (4) to connect the two; the metamaterial layer (3) is composed of multiple metamaterial units arranged in a ring array, and the metamaterial unit is a metal copper sheet with a hollow dumbbell pattern.

2. The coaxial magnetron with external cavity loading metamaterial according to claim 1, characterized in that, The anode blade group (1) includes 28 anode blades, each anode blade being 5.96 mm long, 1.78 mm wide, and 8.2 mm high.

3. The coaxial magnetron with externally loaded metamaterial according to claim 1, characterized in that, The anode cylinder (2) has a thickness of 1.5 mm, a height of 23.1 mm, and a diameter of 35.68 mm.

4. The coaxial magnetron with externally loaded metamaterial according to claim 1, characterized in that, The number of coupling gaps (5) is 14, arranged in a uniform ring array; each coupling gap (5) has a height of 20.1 mm, a width of 0.8 mm, and is located in the middle of the two anode blades.

5. The coaxial magnetron with externally loaded metamaterial according to claim 1, characterized in that, The outer cylinder (4) has a diameter of 71 mm, a height of 22 mm, and a thickness of 1.5 mm.

6. The coaxial magnetron with externally loaded metamaterial according to claim 1, characterized in that, The thickness of the metamaterial unit is 0.5 mm; the total length of the hollow dumbbell pattern is 15 mm, the gap in the middle is 1.2 mm, and the diameter of the circular parts at both ends is 5.6 mm; the metamaterial units are arranged in a uniform ring array with an interval of 15°.

7. The coaxial magnetron with an externally loaded metamaterial according to any one of claims 1 to 6, characterized in that, The metamaterial layer (3) has a resonant peak at a frequency of 9.2 GHz, which is used to suppress the competing modes of the coaxial magnetron.

8. The coaxial magnetron with an externally loaded metamaterial according to any one of claims 1 to 6, characterized in that, The metamaterial layer (3) is made of metallic copper and is used to improve the heat dissipation performance of the anode cylinder (2).

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