A coaxial magnetron with a dielectric material as an external cavity energy storage element and its application

Abstract

The present invention relates to a coaxial magnetron with a dielectric material as an external cavity energy storage element, which includes a cathode disposed at the center and anode vanes coaxial with the cathode; an inner cavity is formed between the cathode and the anode vanes, and an external cavity coaxial with the outer ring is formed by the anode vanes; wherein, the external cavity is filled with a dielectric as an energy storage element. The coaxial magnetron of the present invention using a dielectric to fill the external cavity has a reduced volume of the external cavity compared with a general coaxial magnetron, so the applicable frequency band and usage scenarios of the coaxial magnetron can be broadened; at the same time, a cathode with a larger emission area can be used while keeping the overall size of the magnetron unchanged to obtain a larger output power, thereby greatly improving the performance of the magnetron.

Description

Technical Field

[0001] The present invention relates to a coaxial magnetron, and particularly to a coaxial magnetron using a dielectric material as an external cavity energy storage element and its application. Background Art

[0002] A magnetron is a common vacuum electron tube, which is essentially an orthogonal field oscillator and a high-power microwave source in microwave technology. Compared with a klystron, the magnetron has the advantages of high efficiency, low operating voltage, simple structure, small size, light weight, and low cost. At present, magnetrons have been widely used in the fields of national defense, industry, agriculture, medical treatment, etc.

[0003] A coaxial magnetron is a common type of magnetron. In addition to having a cavity similar to that of an ordinary conventional magnetron as the inner cavity, it also has a coaxial outer cavity. During application, by adjusting the height of the frequency modulation cover plate, the purpose of tuning the frequency can be achieved. Compared with an ordinary magnetron, the coaxial magnetron has the characteristics of large output power, high efficiency, wide tuning range, good frequency stability, and long tube life. However, due to the introduction of the coaxial outer cavity, the volume of the magnetron has become larger. The introduction of the coaxial outer cavity generally makes the volume of the coaxial magnetron larger, which leads to two problems: First, since the lower the frequency of a microwave device, the larger its size, the coaxial magnetron can generally only be applied to high-frequency bands such as C and X, and cannot be applied to low-frequency bands such as S and L. Second, limited by the actual volume and weight, the cathode emission area of the coaxial magnetron is limited, resulting in limited emission current of the magnetron, and thus limited output power. Summary of the Invention

[0004] The purpose of the present invention is to provide a coaxial magnetron using a dielectric material as an external cavity energy storage element, including a cathode arranged at the center and anode vanes coaxial with the cathode; an inner cavity is formed between the cathode and the anode vanes, and a coaxial outer cavity is formed between the anode vanes and the outer ring;

[0005] The outer ring is the circular shell of the coaxial magnetron.

[0006] Wherein, the outer cavity is filled with a dielectric.

[0007] The coaxial magnetron is proposed to improve the stability of the magnetron, but in the prior art, a part of the compactness needs to be sacrificed. The design of the present invention can improve the compactness of the coaxial magnetron on the premise of ensuring efficiency, and further reduce the size of the coaxial magnetron.

[0008] The main advantage of a coaxial magnetron is its good stability, which benefits from the fact that most of its energy is stored in the outer cavity. In the prior art, the outer cavity of a coaxial magnetron is a vacuum cavity surrounded by oxygen-free copper material, while the present invention proposes to use a cavity filled with a dielectric as the energy storage element of the coaxial magnetron. At this time, it is necessary to perform magnetron microwave and electron dynamics simulations based on the electrical properties of the selectable dielectric materials, with the overall tube efficiency, output power, stability, etc. as the optimization objectives, and iterate repeatedly to obtain various mechanical parameters, including the sizes of the cathode, inner cavity, outer cavity, as well as the size and filling position of the dielectric material, and then conduct the design, trial production, and testing of the actual sample tube, and through multiple optimizations and improvements, finally determine various mechanical parameters.

[0009] Further, an upper pole shoe is provided at the upper end of the cathode, and a lower pole shoe is provided at the lower end.

[0010] Further, the inner cavity and the outer cavity are separated by a coupling slit between the inner and outer cavities.

[0011] The coupling slit is used for microwave coupling between the inner cavity and the outer cavity.

[0012] Further, the coaxial magnetron further includes a magnetron output port provided on the outer ring.

[0013] Further, the coaxial magnetron further includes a tuning cover plate for adjusting the output power of the magnetron.

[0014] Further, the dielectric is an electro-vacuum dielectric, preferably one or more of quartz glass, alumina ceramic (purity 99%), diamond, and single crystal alumina (synthetic sapphire); especially when quartz and ceramic are used as the dielectric, their filling effects are excellent; especially in combination with the partial filling method.

[0015] Further, the dielectric is filled entirely or partially in the outer cavity of the coaxial magnetron.

[0016] Preferably, the partial filling is outer filling. The outer filling specifically refers to the side of the outer cavity far from the cathode.

[0017] Among them, the connection method between the dielectric and the cavity is welding, clamping, or chiseling.

[0018] The application of the coaxial magnetron in the fields of non-destructive testing, industrial flaw detection, medical treatment, well logging, etc.

[0019] In the prior art, the coaxial magnetron was proposed to improve the stability of the magnetron; but it sacrifices a part of the compactness. On the basis of optimizing the above technical features, the present invention reasonably designs to improve the compactness of the coaxial magnetron, and the size of the magnetron can be adjusted according to actual needs.

[0020] The dielectric material used in the present invention can be a single dielectric, a mixed dielectric, or a stack of multiple dielectrics. The filling method of the dielectric in the outer cavity can be full filling or partial filling, including bottom filling, top filling, inner filling, outer filling, or a combined filling method combining the above situations.

[0021] Among them, it is preferred that the diameter of the cathode is 20 - 40 mm. When using a cathode of this size and using ceramics and / or quartz glass as the dielectric for partial filling, the effect is very ideal; in particular, when using outer filling with a filling thickness of 3 - 5 mm.

[0022] When the following filling methods are used, the output power is the most ideal:

[0023] 1. When the cathode diameter is about 24 mm, the filling dielectric is alumina ceramic with a thickness of 3 - 4 mm, and the outer filling method is used, the output power of the coaxial magnetron is the largest. It is suitable for smaller coaxial magnetrons.

[0024] 2. When the cathode diameter is about 30 mm, the filling dielectric is alumina ceramic with a thickness of 3 mm, and the outer filling method is used, the output power of the coaxial magnetron is the largest. It is suitable for medium-sized coaxial magnetrons.

[0025] 3. When the cathode diameter is about 36 mm, the filling dielectric is quartz glass with a thickness of 5 mm, and the outer filling method is used, the output power of the coaxial magnetron is the largest. It is suitable for coaxial magnetrons with slightly larger sizes.

[0026] A coaxial magnetron provided by the present invention using a dielectric material as an outer cavity energy storage element can greatly reduce the volume of the coaxial outer cavity by filling a suitable dielectric material in the coaxial outer cavity, thereby effectively solving the following two problems.

[0027] First, a coaxial magnetron with a dielectric-filled outer cavity has a smaller volume increase compared to a conventional magnetron. Thus, in the low-frequency band, coaxial magnetrons can also be used in applications with high anti-interference and high stability requirements, so the applicable frequency band and usage scenarios of coaxial magnetrons can be broadened.

[0028] Second, for a coaxial magnetron with a dielectric-filled outer cavity, a cathode with a larger emission area can be used while keeping the overall size of the magnetron unchanged, thereby achieving a higher output power. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of the coaxial magnetron provided for Example 1;

[0030] Figure 2 It is a schematic structural diagram of the coaxial magnetron provided for Examples 2 - 3;

[0031] Figure 3 Schematic diagram of the structure of the coaxial magnetron provided for Examples 4 to 6;

[0032] Figure 4 Schematic diagram of the structure of the coaxial magnetron provided for Example 7;

[0033] In the figure: 1, cathode; 2, anode vane; 3, inner cavity; 4, coupling slit between the inner and outer cavities; 5, outer cavity; 6, magnetron output port; 7, tuning cover plate; 8, upper pole shoe; 9, lower pole shoe; 10, filling medium. Specific embodiments

[0034] The following examples are used to illustrate the present invention, but do not limit the scope of the present invention.

[0035] Example 1

[0036] This example provides a coaxial magnetron with the outer cavity fully filled with quartz glass. As Figure 1 shown, it includes a cathode 1 arranged at the center and an anode vane 2 coaxial with the cathode 1; an inner cavity 3 is formed between the cathode 1 and the anode vane 2, and a coaxial outer cavity 5 is formed between the anode vane 2 and the outer ring; a tuning cover plate 7 is arranged on the cover plate.

[0037] Among them, the outer cavity 5 is filled with quartz glass, and the filling method is full filling, that is, the medium fills the outer cavity 5.

[0038] Among them, an upper pole shoe 8 is arranged at the upper end of the cathode 1, and a lower pole shoe 9 is arranged at the lower end of the cathode 1.

[0039] Among them, the inner cavity 3 and the outer cavity 5 are separated by a coupling slit 4 between the inner and outer cavities.

[0040] Among them, the coaxial magnetron further includes a magnetron output port 6 arranged on the outer ring.

[0041] This example uses a cathode of the same size as that of a general coaxial magnetron, but the outer diameter of the magnetron can be reduced to about 85 mm.

[0042] Example 2

[0043] This example provides a coaxial magnetron with 99% alumina ceramic partially filling the outer cavity. As Figure 2 shown, it includes a cathode 1 arranged at the center and an anode vane 2 coaxial with the cathode 1; an inner cavity 3 is formed between the cathode 1 and the anode vane 2, and a coaxial outer cavity 5 is formed between the anode vane 2 and the outer ring; a tuning cover plate 7 is arranged on the cover plate.

[0044] Among them, the outer cavity 5 is filled with 99% alumina ceramic, and the filling method is partial filling. Specifically, the medium is filled on the outside of the outer cavity 5, with a thickness of about 3 mm.

[0045] Among them, an upper pole shoe 8 is provided at the upper end of the cathode 1, and a lower pole shoe 9 is provided at the lower end.

[0046] Among them, the inner cavity 3 and the outer cavity 5 are separated by a coupling slit 4 between the inner and outer cavities.

[0047] Among them, the coaxial magnetron further includes a magnetron output port 6 provided on the outer ring.

[0048] This embodiment uses a cathode with the same size as that of a general coaxial magnetron, but the outer diameter of the magnetron can be reduced to about 85 mm.

[0049] Embodiment 3

[0050] This embodiment provides a coaxial magnetron with an outer cavity partially filled with alumina ceramics. As Figure 2 shown, the same as Embodiment 2 is that 99% alumina ceramics are used for filling, and the difference is that the thickness of the ceramics is about 4 mm. The corresponding outer diameter of the magnetron can be further reduced to 80 mm.

[0051] Embodiment 4

[0052] This embodiment provides a coaxial magnetron with an outer cavity partially filled with quartz glass. As Figure 3 shown, it includes a cathode 1 provided at the center, and anode vanes 2 coaxial with the cathode 1; an inner cavity 3 is formed between the cathode 1 and the anode vanes 2, and a coaxial outer cavity 5 is formed between the anode vanes 2 and the outer ring; a tuning cover plate 7 is provided on the cover plate.

[0053] Among them, the outer cavity 5 is filled with quartz glass, and the filling method is partial filling. Specifically, the medium is filled on the outside of the outer cavity 5 with a thickness of about 3 mm.

[0054] Among them, an upper pole shoe 8 is provided at the upper end of the cathode 1, and a lower pole shoe 9 is provided at the lower end.

[0055] Among them, the inner cavity 3 and the outer cavity 5 are separated by a coupling slit 4 between the inner and outer cavities.

[0056] Among them, the coaxial magnetron further includes a magnetron output port 6 provided on the outer ring.

[0057] This embodiment uses a magnetron outer diameter with the same size as that of a general coaxial magnetron, that is, 120 mm, but uses a cathode with a larger size. Specifically, the diameter of the cathode is about 30 mm.

[0058] Embodiment 5

[0059] This embodiment provides a coaxial magnetron with an outer cavity partially filled with quartz glass. As Figure 3 shown.

[0060] The same as in Example 4 is that quartz glass is used, and the difference is that the thickness of the quartz glass is about 4 mm.

[0061] The same as in Example 4 is that the outer diameter of the magnetron is the same as that of a general coaxial magnetron, that is, 120 mm, and the difference is that the cathode diameter is about 36 mm.

[0062] Example 6

[0063] This example provides a coaxial magnetron with an outer cavity partially filled with alumina ceramics, as Figure 3 shown.

[0064] The difference from Example 4 is that the outside of the alumina ceramics is filled, and the ceramic thickness is about 3 mm.

[0065] The same as in Example 4 is that the outer diameter of the magnetron is the same as that of a general coaxial magnetron, that is, 120 mm, and the difference is that the cathode diameter is about 36 mm.

[0066] Example 7

[0067] This example provides a coaxial magnetron with an outer cavity partially filled with quartz glass, as Figure 4 shown, including a cathode 1 arranged at the center and anode vanes 2 coaxial with the cathode 1; an inner cavity 3 is formed between the cathode 1 and the anode vanes 2, and an outer cavity 5 coaxial with the outer ring is formed by the anode vanes 2; a tuning cover plate 7 is arranged on the cover plate.

[0068] Among them, the outer cavity 5 is filled with quartz glass, and the filling method is full filling, that is, the medium fills the outer cavity 5.

[0069] Among them, an upper pole shoe 8 is arranged at the upper end of the cathode 1, and a lower pole shoe 9 is arranged at the lower end.

[0070] Among them, the inner cavity 3 and the outer cavity 5 are separated by an inner-outer cavity coupling slit 4.

[0071] Among them, the coaxial magnetron further includes a magnetron output port 6 arranged on the outer ring. The cathode size of this example is 36 mm, which is larger than that of a general coaxial magnetron, but the outer diameter is smaller than that of a general coaxial magnetron, about 100 mm.

[0072] Test comparison

[0073] The coaxial magnetrons provided in Examples 1 to 7, and the coaxial magnetrons without a medium filled in the outer cavity 5 (Reference Example 1 and Reference Example 2) were simulated by computer microwave and electron dynamics and compared. The results are as follows:

[0074]

[0075] It can be found that Example 1 using fully filled quartz material and Example 2 using partially filled alumina ceramic material have the same output power as a general coaxial magnetron without filled medium; however, the outer diameter can be reduced by about 30%; it can be seen that filling the medium can make the coaxial magnetron more compact and smaller in volume; it broadens the application market of the coaxial magnetron.

[0076] Examples 4 - 6 have the same appearance size as the coaxial magnetron without filled medium, but a cathode with a larger diameter can be used, so the output power can be correspondingly increased, which greatly improves the performance of the magnetron. The outer diameter of the coaxial provided in Example 7 is reduced by 17%, and at the same time the output power of the magnetron is increased by 35%.

[0077] Although the present invention has been described in detail above with general descriptions, specific embodiments and experiments, based on the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A coaxial magnetron with a dielectric material as an external cavity energy storage element, characterized in that, It includes a cathode (1) arranged at the center and an anode vane (2) coaxial with the cathode (1); an inner cavity (3) is formed between the cathode (1) and the anode vane (2), and an outer cavity (5) coaxial with the outer ring is formed by the anode vane (2); wherein, a medium is filled in the outer cavity (5); the medium is selected from one or more of fused quartz, alumina ceramics, diamond, and single crystal alumina; the medium is fully filled or partially filled in the outer cavity of the coaxial magnetron; the partial filling is the outer filling; the diameter of the cathode is 20 - 40 mm; the thickness of the partial filling is 3 - 5 mm.

2. The coaxial magnetron according to claim 1, characterized in that, An upper pole shoe (8) is arranged at the upper end of the cathode (1), and a lower pole shoe (9) is arranged at the lower end of the cathode (1).

3. The coaxial magnetron according to claim 1, characterized in that, The inner cavity (3) and the outer cavity (5) are separated by a coupling slit (4) between the inner and outer cavities.

4. The coaxial magnetron according to claim 1, characterized in that, It further includes a magnetron output port (6) arranged on the outer ring.

5. The coaxial magnetron according to claim 1, characterized in that, It further includes a tuning cover plate (7).

6. The coaxial magnetron according to any one of claims 1 to 5, characterized in that, The connection mode of the medium and the cavity is welding, clamping or chiseling.

7. Application of the coaxial magnetron according to any one of claims 1 - 6 in non-destructive testing.

8. Application of the coaxial magnetron according to any one of claims 1 - 6 in the fields of industrial flaw detection, medical treatment, and well logging.

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