Coaxial resonant cavity with high micro-discharge threshold and filter

Abstract

The coaxial resonant cavity with the high micro-discharge threshold value comprises a resonant cavity body and a bearing column coaxially arranged at the inner bottom of the resonant cavity body, and further comprises a loading disc coaxially arranged in the resonant cavity body and fixedly arranged on the upper surface of the bearing column, the lower surface of the loading disc is a perfect circle, and the upper surface of the loading disc is of a non-planar structure. Through reasonable arrangement of component structures, a flat plate structure can be prevented from being formed between the loading disc and the inner top surface of the resonant cavity to the maximum extent, under the condition of the same size, when the loading disc is applied to a filter or a multiplexer, the micro-discharge threshold value can be remarkably improved, meanwhile, the smaller size and weight are achieved for the same power requirement, and the cost is reduced. The current requirements on miniaturization, light weight and high power of satellite-borne products are met; the technical problems that a conventional high-power coaxial filter is large in size, heavy in mass and limited in power are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of microwave communications, and in particular relates to a coaxial resonant cavity and a filter with a high micro-discharge threshold. Background Art

[0002] In recent years, with the continuous improvement of satellite development technology and microwave devices, the required RF power and channels have also been increasing. The application of high-power RF has put forward new and higher requirements for the safe operation of satellites and microwave devices. High-power microwave devices are prone to resonant discharge in a vacuum, that is, micro-discharge. Designing microwave devices with appropriate micro-discharge suppression is of great significance to ensure the normal operation of equipment in orbit.

[0003] Coaxial cavity filters are widely used in civil, commercial, and military communication systems. Coaxial cavity filters are generally used in the design of satellite-borne high-power products. In order to suppress the occurrence of micro-discharge, the distance between the inner conductor and the cover plate and the cavity wall is generally increased to increase the micro-discharge threshold, resulting in large volume and heavy weight of high-power coaxial cavity filters. In order to meet the development trend of communication satellite technology, miniaturized, lightweight, high-reliability, and high micro-discharge threshold coaxial filters have become an urgent need for current communication satellite microwave communications. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a coaxial resonant cavity and filter with a high micro-discharge threshold, which solves the technical problems of large volume, heavy mass and limited power capacity of conventional high-power coaxial filters.

[0005] To achieve the above object, the technical solution adopted by the present invention includes:

[0006] A coaxial resonant cavity with a high micro-discharge threshold comprises a resonant cavity and a bearing column coaxially arranged at the inner bottom of the resonant cavity, and also comprises a loading plate coaxially arranged in the resonant cavity and fixed on the upper surface of the bearing column, wherein the lower surface of the loading plate is a perfect circle and the upper surface of the loading plate is a non-planar structure.

[0007] Preferably, the upper surface of the loading disk is a spherical surface, a curved surface or an inclined surface.

[0008] Preferably, the upper surface of the loading disk is a semi-spherical surface.

[0009] Preferably, the wide side of the resonant cavity is D, the outer diameter of the supporting column is d1, the outer diameter of the lower surface of the loading plate is d2, the value of d2 / d1 is close to 2 / 1, and the value of D / d1 is close to 10 / 3; the vertical distance from the highest point of the upper surface of the loading plate to the top surface of the resonant cavity is df, and the value of df is ≥0.5mm.

[0010] Preferably, the value of d2 / d1 is close to 2 / 1, the value of D / d1 is close to 10 / 3, and the value of df is ≥ 0.5 mm.

[0011] A coaxial filter comprises the coaxial resonant cavity with a high micro-discharge threshold disclosed in the present application.

[0012] Compared with the prior art, the advantages of the present invention are:

[0013] (1) The coaxial resonant cavity with a high micro-discharge threshold of the present invention can avoid the formation of a flat structure between the loading disk and the top surface of the resonant cavity to the greatest extent by reasonably setting the component structure. Under the same size conditions, when applied to a filter or a multiplexer, its micro-discharge threshold can be significantly improved. At the same time, for the same power requirement, a smaller size and weight can be achieved, meeting the current demand for miniaturization, lightweight and high power of satellite-borne products.

[0014] (2) The coaxial resonant cavity and filter with a high micro-discharge threshold of the present invention achieve different resonant frequencies and improve the scope of use by reasonably setting the component structure and changing the diameter d2 of the lower surface of the loading disk and the vertical distance df from the highest point of the upper surface of the loading disk to the top surface of the resonant cavity during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0016] Figure 1 It is a schematic structural diagram of a coaxial resonant cavity with a high micro-discharge threshold according to Example 1;

[0017] Figure 2 It is a schematic structural diagram of a coaxial resonant cavity with a high micro-discharge threshold according to Example 2;

[0018] Figure 3 The coaxial resonant cavity in the comparative example is conventionally loaded with a capacitor column;

[0019] Figure 4 This is a field distribution diagram of the coaxial resonant cavity with a high micro-discharge threshold in Example 1;

[0020] Figure 5 This is a field distribution diagram of the coaxial resonant cavity with a high micro-discharge threshold in Example 2;

[0021] Figure 6 is a field distribution diagram of a coaxial resonant cavity traditionally loaded with a capacitor column in a comparative example;

[0022] Figure 7 It is a structural schematic diagram of the coaxial resonant cavity of Example 1 applied to a coaxial filter;

[0023] Figure 8It is a schematic structural diagram of the coaxial resonant cavity of Example 2 applied to a coaxial filter;

[0024] Fig. 9 A schematic diagram of the structure of a coaxial resonant cavity used in a coaxial filter in a comparative example;

[0025] Fig.10 The micro-discharge threshold simulation result of the coaxial filter in Example 1;

[0026] Fig.11 The micro-discharge threshold simulation result of the coaxial filter of Example 2;

[0027] Fig.12 The micro-discharge threshold simulation result of the coaxial filter of the comparative example of the embodiment;

[0028] Fig.13 This is a comparison chart of the simulation results of the three filters in the comparative example.

[0029] The symbols in the figure represent:

[0030] 1 resonant cavity, 2 bearing column, 3 loading plate DETAILED DESCRIPTION

[0031] The invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the invention.

[0032] It should be noted that the directional terms mentioned in this article, such as "inner cavity", "inner periphery", "inner wall" and "outside", are consistent with the specific directions on the paper of the drawings in the specification or the corresponding directions of the space shown in the drawings; all components and equipment in the present invention, unless otherwise specified, are all components and equipment known in the prior art.

[0033] Example 1

[0034] This embodiment discloses a coaxial resonant cavity with a high micro-discharge threshold, comprising a resonant cavity 1 and a bearing column 2 coaxially arranged on the inner bottom of the resonant cavity 1, and also comprising a loading plate 3 coaxially arranged in the resonant cavity 1 and fixed on the upper surface of the bearing column 2, wherein the lower surface of the loading plate 3 is a perfect circle, and the upper surface of the loading plate 3 is a non-planar structure;

[0035] Its function is: it can avoid the formation of a flat plate structure between the loading disk 3 and the top surface of the resonant cavity 1 to the greatest extent. Under the same size conditions, the resonant cavity of the present application can significantly improve its micro-discharge threshold when applied to a filter or a multiplexer. At the same time, for the same power requirements, it can achieve a smaller size and weight, meeting the current demand for miniaturization, lightweight and high power of satellite-borne products.

[0036] Among them, the materials of various components of the resonant cavity can be selected from conventional metal materials such as aluminum alloy, Invar, copper, etc., and the inner surface of the resonant cavity 1 and the outer surface of the supporting column 2 can be silver-plated or gold-plated; the resonant cavity 1, the supporting column 2 and the loading plate 3 can be partially processed separately, or they can be processed separately by high-precision CNC machine tools, and the product processing accuracy is high. Finally, the supporting column 2 and the resonant cavity 1 are interconnected by screw fastening or welding.

[0037] Specifically, the upper surface of the loading plate 3 is a spherical surface or an arc surface, that is, the upper surface of the loading plate 3 and the top surface of the resonance cavity 1 are avoided to be parallel to each other to the greatest extent, so as to avoid forming a stable electronic resonance structure.

[0038] The upper surface of the loading plate 3 disclosed in this embodiment is a semi-spherical surface. The outer diameter of the bearing column 2 is d1, and the outer diameter of the lower surface of the loading plate 3 is d2, and the value of d2 / d1 is about 2 / 1, preferably 2 / 1; the vertical distance from the highest point of the upper surface of the loading plate 3 to the top surface of the resonance cavity 1 is df, and the value of df is ≥0.5mm, preferably 2mm; the width of the resonance cavity is D, and the value of D / d1 is close to about 10 / 3, preferably 10 / 3, to maximize the energy storage of the resonator.

[0039] Its function is: when in use, the diameter d2 of the lower surface of the loading disk 3, the width D of the resonant cavity, and the vertical distance df from the highest point of the upper surface of the loading disk 3 to the top surface of the resonant cavity 1 are changed to achieve different resonant frequencies, thereby improving the application range of the coaxial resonant cavity of the present application in filters and multiplexers.

[0040] The size of the resonant cavity 1 disclosed in this embodiment is 35mm×35mm×40mm, the outer diameter d1 of the bearing column 2 is 5mm, the height h1 is 25mm, the outer diameter d2 of the lower surface of the loading plate 3 is 10mm, the height h2 is 10mm

[0041] This embodiment also discloses a coaxial filter, including the coaxial resonant cavity with a high micro-discharge threshold disclosed in this embodiment, such as Figure 7 shown.

[0042] Example 2

[0043] like Figure 2 This embodiment discloses a coaxial resonant cavity with a high micro-discharge threshold. The difference from Embodiment 1 is that the upper surface of the loading plate 3 is an inclined surface, that is, the upper surface of the loading plate 3 and the top surface of the resonant cavity 1 are avoided to the greatest extent to be parallel to each other, thereby avoiding the formation of a stable electronic resonance structure.

[0044] This embodiment also discloses a coaxial filter, including the coaxial resonant cavity with a high micro-discharge threshold disclosed in this embodiment, such as Figure 8 shown.

[0045] Comparative Example

[0046] This comparative example discloses a coaxial resonant cavity that is also loaded with a capacitor column. The difference between the coaxial resonant cavity and the resonant cavity disclosed in Example 1 is that the loading disk is a cylinder, and the other dimensions are the same as those in Example 1.

[0047] like Figure 4 —— Figure 6 The electric field distribution diagrams of the coaxial resonant cavity of Example 1, the coaxial resonant cavity of Example 2 and the coaxial resonant cavity of the comparative example are shown respectively. The characteristic of the electric field is that it is emitted vertically from the metal surface and incident vertically on another metal surface. The electric field in the resonator is an alternating resonant electric field. Figure 4 is the electric field distribution in the spherical resonator, Figure 5 is the electric field distribution diagram in the slant resonator, Figure 6 The electric field distribution in a conventional loaded disk resonator. Figure 6 It can be seen from the electric field distribution diagram shown that the top of the traditional resonator and the lower surface of the cover form a flat structure. Driven by the electric field, the free electrons inside the resonant cavity are accelerated to hit the metal surface, exciting more secondary electrons. Driven by the electric field, the secondary electrons are accelerated to hit the metal surface at the other end to produce more secondary electrons. This cycle repeats to form a resonant discharge phenomenon. Figure 4 and Figure 5 It can be seen from the electric field distribution diagram that a flat structure cannot be formed between the outer surface of the top of the resonator and the cavity wall and cover of the resonant cavity, so that a resonant discharge phenomenon cannot be formed inside the resonant cavity, which is manifested as an increase in the micro-discharge threshold of the resonator.

[0048] This comparative example also discloses a coaxial filter, which is a conventional loaded disk resonator, including a coaxial resonant cavity with a high micro-discharge threshold disclosed in this comparative example, such as Fig. 9 shown.

[0049] The coaxial filter of Example 1, the coaxial filter of Example 2 and the conventional loaded disk resonator of the comparative example are compared respectively. The three filters have the same external dimensions, and the frequencies and bandwidths of the filters are consistent. The comparison of the dimensions of the three filters and their respective power capacities is shown in Table 1.

[0050] Table 1 Comparison of three filter sizes and their power capacity

[0051]

[0052]

[0053] like Fig.10 —— Fig.13 As shown, Fig.10 The figure shows the simulation results of the micro-discharge threshold of the filter designed with spherical resonator. Fig.11 The figure shows the simulation results of the micro-discharge threshold of the filter designed with a slope resonator. Fig.12Shown are the simulation results of the micro-discharge threshold of filters designed with traditional loaded disk resonators. The simulation results of the micro-discharge threshold of the three filters are based on the micro-discharge simulation software SPARK3D. Fig.13 These are the simulated S parameters of three third-order filters based on resonator design. The dimensions of the three filters are exactly the same. By adjusting the dimensions of the resonator, the center frequency of the three filters is 1.5 GHz and the bandwidth is 100 MHz. S parameters are an important parameter in microwave transmission, also known as scattering parameters, which are used to describe the transmission and reflection characteristics of microwave signals in filters. Among them, S11 describes the reflection characteristics of microwave signals in filters, and S21 describes the transmission characteristics of microwave signals in filters, so S11 and S21 are two aspects that characterize the transmission and reflection characteristics of filters. Fig.13 Among the 6 curves, S11_plane represents the reflection characteristics of the third-order filter designed with a traditional loading disk resonator, and S21_plane represents the transmission characteristics of the third-order filter designed with a traditional loading disk resonator; S11_sphere represents the reflection characteristics of the third-order filter designed with a spherical resonator, and S21_sphere represents the transmission characteristics of the third-order filter designed with a spherical resonator; S11_slope represents the reflection characteristics of the third-order filter designed with a slope resonator, and S21_slope represents the transmission characteristics of the third-order filter designed with a slope resonator. Among the 6 curves, 3 S11 and 3 S21 overlap, further indicating that the simulation results of the three filters are consistent.

[0054] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0055] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0056] In addition, the various different implementation modes disclosed in this solution may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the content invented by the present disclosure.

Claims

1. A coaxial resonant cavity with a high micro-discharge threshold, comprising a resonant cavity (1) and a bearing column (2) coaxially arranged on the inner bottom of the resonant cavity (1), characterized in that: It also comprises a loading plate (3) coaxially arranged in the resonant cavity (1) and fixedly arranged on the upper surface of the bearing column (2); the lower surface of the loading plate (3) is a perfect circle, and the upper surface of the loading plate (3) is a non-planar structure.

2. The coaxial resonant cavity with a high micro-discharge threshold as claimed in claim 1, characterized in that: The upper surface of the loading plate (3) is a non-planar structure such as a spherical surface, a curved surface or an inclined surface.

3. The coaxial resonant cavity with a high micro-discharge threshold as claimed in claim 2, characterized in that: The upper surface of the loading disk (3) is a semi-spherical surface.

4. The coaxial resonant cavity with a high micro-discharge threshold as described in any one of claims 1 to 3, characterized in that: The wide side of the resonant cavity (1) is D, the outer diameter of the bearing column (2) is d1, the outer diameter of the lower surface of the loading plate (3) is d2, the value of d2 / d1 is close to 2 / 1, and the value of D / d1 is close to 10 / 3; The vertical distance from the highest point on the upper surface of the loading plate (3) to the top surface of the resonant cavity (1) is df, and the value of df is ≥0.5 mm.

5. The coaxial resonant cavity with a high micro-discharge threshold as claimed in claim 4, characterized in that: The value of d2 / d1 is close to 2 / 1, the value of D / d1 is close to 10 / 3, and the value of df is ≥0.5 mm.

6. A coaxial filter, characterized in that: A coaxial resonant cavity with a high micro-discharge threshold comprising the coaxial resonant cavity as described in any one of claims 1-5.

Images