Passive hydrogen maser compact magnetron microwave cavity

Abstract

The present application relates to the technical field of small magnetron microwave cavity, and discloses a passive hydrogen atom frequency standard small magnetron microwave cavity.The passive hydrogen atom frequency standard small magnetron microwave cavity comprises a cavity tube and four pole pieces, a sealed microwave resonant cavity is formed in the cavity tube, one coupling ring is arranged on each side of the side surface of the cavity tube, the two coupling rings are respectively used for input and output of microwave signals, the outer diameter of the cavity tube is 111mm, the inner diameter of the cavity tube is 105mm, and the height is 188.5mm; the pole piece is in an arc structure, four pole pieces are arranged in a ring in the sealed microwave resonant cavity, a connecting column is protrudingly arranged on the side of each pole piece away from the center of the plurality of pole pieces, the connecting column is connected to the side wall of the cavity tube, the annular inner diameter surrounded by the four pole pieces is 61.6mm, the annular outer diameter is 67.4mm, the height of the pole piece is 145mm, and the spacing between each adjacent two pole pieces is 3.8mm.The passive hydrogen atom frequency standard small magnetron microwave cavity is light in mass, small in size, and meets the magnetic field environment requirement of hydrogen atom transition of the passive hydrogen atom frequency standard.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of small magnetron microwave cavity, and particularly relates to a passive hydrogen maser small magnetron microwave cavity. BACKGROUND

[0002] The hydrogen maser is widely used in satellite navigation, aviation and communication fields due to its excellent medium and long-term stability. The passive hydrogen maser is divided into a physical part and a circuit part, the physical part is a core component of the whole machine, and the performance of the physical part determines the frequency stability of the hydrogen maser. The microwave cavity is an important component of the physical part, provides an electromagnetic field environment for the hydrogen atom hyperfine level transition, and makes the hydrogen atom produce high level to low level transition. The volume and weight of the microwave cavity are key components to determine the volume and weight of the physical part. At present, the microwave cavity used by the passive hydrogen maser is a magnetron microwave cavity with an internal diameter of 118 mm, and the physical part accounts for more than 65% of the weight of the passive hydrogen maser. That is, the volume of the passive hydrogen maser is large, and the weight is heavy, which limits the application of small frequency markers. SUMMARY

[0003] Based on the above, the purpose of the present application is to provide a passive hydrogen maser small magnetron microwave cavity which is lighter in quality and smaller in volume, and meets the frequency performance of the passive hydrogen maser.

[0004] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0005] A passive hydrogen maser small magnetron microwave cavity comprises:

[0006] A cavity barrel is formed with a sealed microwave resonant cavity inside, and one coupling ring is arranged on each side of the side wall of the cavity barrel, the two coupling rings are respectively used for input and output of microwave signals, the outer diameter of the cavity barrel is 111 mm, the inner diameter of the cavity barrel is 105 mm, and the height is 188.5 mm.

[0007] Four pole pieces are arranged in the form of an arc structure, and the four pole pieces are arranged in a ring in the sealed microwave resonant cavity, one side of each pole piece away from the center of the ring is provided with a connecting column, the connecting column is connected to the side wall of the cavity barrel, the inner diameter of the ring surrounded by the four pole pieces is 61.6 mm, the outer diameter is 67.4 mm, and the height of the pole piece is 145 mm, and the spacing between each adjacent two pole pieces is 3.8 mm.

[0008] As a preferred scheme of the passive hydrogen maser small magnetron microwave cavity, one side of each pole piece away from the center of the ring is provided with two connecting columns, the two connecting columns are arranged in a spaced relationship along the height direction of the pole piece, and are flush with the two end surfaces of the pole piece, respectively.

[0009] As a preferred solution of the passive hydrogen atom frequency standard small magnetron microwave cavity, the application further comprises:

[0010] Four filling media, each of which is arranged between one of the pole pieces and the cavity barrel and connected between two of the connecting columns on one of the pole pieces.

[0011] As a preferred solution of the passive hydrogen atom frequency standard small magnetron microwave cavity, opposite surfaces of the two connecting columns on each of the pole pieces are provided with mounting grooves, and two ends of the filling media are respectively inserted into the two mounting grooves.

[0012] As a preferred solution of the passive hydrogen atom frequency standard small magnetron microwave cavity, the filling media are quartz or polytetrafluoroethylene.

[0013] As a preferred solution of the passive hydrogen atom frequency standard small magnetron microwave cavity, each of the connecting columns is connected to the sidewall of the cavity barrel by a screw.

[0014] As a preferred solution of the passive hydrogen atom frequency standard small magnetron microwave cavity, the pole pieces and the connecting columns are integrally formed.

[0015] As a preferred solution of the passive hydrogen atom frequency standard small magnetron microwave cavity, the cavity barrel comprises a barrel body in a hollow cylindrical structure, and a first cavity cover and a second cavity cover are respectively detachably sealed at two ends of the barrel body, so that the closed microwave resonant cavity is formed between the barrel body, the first cavity cover and the second cavity cover.

[0016] As a preferred solution of the passive hydrogen atom frequency standard small magnetron microwave cavity, a heating wire is wound on the outer wall of the cavity barrel.

[0017] As a preferred solution of the passive hydrogen atom frequency standard small magnetron microwave cavity, the outer wall of the cavity barrel is provided with a plurality of accommodation grooves in a spiral distribution, and the heating wire is embedded in the accommodation grooves.

[0018] The application has the following beneficial effects:

[0019] The application provides a passive hydrogen atom frequency standard small magnetron microwave cavity, which comprises a cavity barrel and four pole pieces, and the pole pieces are fixed in the cavity barrel by connecting columns, so that the stability is better. In use, a storage bubble containing hydrogen atoms is placed in the closed microwave resonant cavity, and a microwave signal is input through a coupling ring, electromagnetic waves in the microwave cavity oscillate in the form of standing waves, an electromagnetic field of a TE011 mode with a resonance center frequency close to a hydrogen atom transition frequency is formed, and hydrogen atoms in the storage bubble realize F=1, m F =0 and F=0, m FThe hyperfine level transition between the energy levels of 2F=1, mF=0 and 2F=0, mF=0, with a center frequency of 1.420405751 GHz, is used as the standard signal of the passive hydrogen atom frequency standard. That is, by reasonably arranging four pole pieces in a small size cavity, the small magnetron microwave cavity of the passive hydrogen atom frequency standard is small in overall volume and weight while meeting the performance of the passive hydrogen atom frequency standard. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art according to the contents of the embodiments of the present application and the drawings without any creative labor.

[0021] Figure 1 is a structural schematic diagram of a cavity provided by the embodiments of the present application;

[0022] Figure 2 is a structural schematic diagram of a cylinder and a pole piece provided by the embodiments of the present application;

[0023] Figure 3 is a structural schematic diagram of a pole piece and a storage bubble provided by the embodiments of the present application;

[0024] Figure 4 is a structural schematic diagram of a pole piece and a filling medium provided by the embodiments of the present application;

[0025] Figure 5 is a structural schematic diagram of a single pole piece provided by the embodiments of the present application.

[0026] In the drawings:

[0027] 1, cavity; 11, cylinder; 110, accommodating groove; 12, first cavity cover; 13, second cavity cover;

[0028] 2, pole piece; 21, connecting column; 210, threaded hole;

[0029] 3, filling medium;

[0030] 4, heating wire;

[0031] 5, coupling ring;

[0032] 100, storage bubble. DETAILED DESCRIPTION

[0033] The application will be further described below in conjunction with the drawings and embodiments. It is to be understood that the specific embodiments described herein are intended to be illustrative only and not limiting of the application. It is also to be understood that the terminology used herein is for the purpose of describing the particular embodiments only and is not intended to be limiting.

[0034] In the description of the present application, unless otherwise clearly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or detachably connected, or integrated; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0035] In the present application, unless otherwise clearly specified and limited, the first feature "on" or "under" the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "under", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0036] In the description of the present embodiment, the terms "up", "down", "left", "right" and other orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, unless otherwise stated, the meaning of "a plurality of" is two or more. In addition, the terms "first", "second" are only used to distinguish in the description, and have no special meaning.

[0037] As Figures 1 to 5As shown, the embodiment provides a passive hydrogen atom frequency standard small magnetron microwave cavity, which comprises a cavity tube 1 and four pole pieces 2, a sealed microwave resonant cavity is formed in the cavity tube 1, and one coupling ring 5 is arranged on each side of the side wall of the cavity tube 1, and the two coupling rings 5 are respectively used for input and output of microwave signals. The outer diameter of the cavity tube 1 is 111 mm, the inner diameter of the cavity tube 1 is 105 mm, and the height is 188.5 mm. The pole piece 2 is in an arc structure, and the four pole pieces 2 are arranged in a ring in the sealed microwave resonant cavity. One side of each pole piece 2 away from the center of the plurality of pole pieces 2 is provided with a connecting column 21, and the connecting column 21 is connected to the side wall of the cavity tube 1. The annular inner diameter surrounded by the four pole pieces 2 is 61.6 mm, and the outer diameter is 67.4 mm. The height of the pole piece 2 is 145 mm, and the spacing between each adjacent two pole pieces 2 is 3.8 mm. The pole piece 2 is fixed in the cavity tube 1 through the connecting column 21, and the stability is better. In use, the storage bubble 100 containing hydrogen atoms is placed in the sealed microwave resonant cavity, and the microwave signal is input through the coupling ring 5. The electromagnetic wave in the microwave cavity oscillates in the form of standing wave, forms an electromagnetic field with a resonance center frequency close to the hydrogen atom transition frequency TE011 mode, and the hydrogen atoms in the storage bubble 100 realize the transition between the hyperfine energy levels F=1, m F =0 and F=0, m F =0. The transition center frequency is 1.420405751 GHz, which is used as the standard signal of the passive hydrogen atom frequency standard. The microwave signal coupled out of the magnetron microwave cavity carries frequency difference information, which is processed by the external circuit part to lock the crystal oscillator frequency on the hydrogen atom transition frequency, and outputs a high-stability signal. That is, by reasonably arranging four pole pieces 2 in a small size cavity tube 1, the passive hydrogen atom frequency standard small magnetron microwave cavity meets the performance of the passive hydrogen atom frequency standard while the overall volume and weight are small, and the volume is reduced by 21% compared with the magnetron microwave cavity in the prior art.

[0038] Specifically, the cavity tube 1 comprises a cylinder body 11, the cylinder body 11 is in a hollow cylindrical structure, and the first cavity cover 12 and the second cavity cover 13 are detachably sealed at both ends of the cylinder body 11 respectively, and a sealed microwave resonant cavity is formed between the cylinder body 11, the first cavity cover 12 and the second cavity cover 13. The first cavity cover 12 and the second cavity cover 13 are detachable, which facilitates the disassembly and assembly of the internal pole piece 2, and also facilitates the placement and removal of the hydrogen atom storage bubble 100. Among them, the first cavity cover 12 and the second cavity cover 13 are detachably connected to the two end faces of the cylinder body 11, respectively, by bolts, which has high connection stability, is convenient to disassemble and assemble, and has low cost.

[0039] More specifically, the cavity cylinder 1 is wrapped with a heating wire 4, and the heating wire 4 is wrapped around the outer circumferential wall of the cylinder body 11, so as to control the temperature of the microwave cavity and make the resonant frequency of the microwave cavity not affected by the ambient temperature. Preferably, the outer wall of the cavity cylinder 1, i.e., the cylinder body 11, is provided with a plurality of accommodation grooves 110 distributed in a spiral manner, and the heating wire 4 is embedded in the accommodation grooves 110, so as to improve the appearance and neatness of the cylinder body 11, and the accommodation grooves 110 can limit the heating wire 4, so as to avoid displacement and slippage of the heating wire 4 and improve the stability and reliability in use. The cross section of the accommodation groove 110 is in a U shape or an arc shape, which is set according to actual requirements. For example, when the cross section of the accommodation groove 110 is in a U shape, the depth and the width are both 1.2 mm, and the spiral distribution is on the outer surface of the cylinder body 11 for 19 turns.

[0040] In the embodiment, two connecting columns 21 are protruded on the side of each pole piece 2 away from the center of the plurality of pole pieces 2, and the two connecting columns 21 are oppositely arranged along the height direction of the pole piece 2 and are flush with the two end surfaces of the pole piece 2, respectively. Under the above structure, the connection stability of each pole piece 2 to the cavity cylinder 1 is better, and the pole piece 2 is not prone to position deviation or shaking, so that the use reliability of the passive hydrogen maser small-size magnetron microwave cavity is better. The length, width and height of each connecting column 21 are 25 mm, 10 mm and 28 mm, respectively, which ensures better connection stability of the pole piece 2 while occupying less space and weighing less, so as to ensure that the overall weight of the passive hydrogen maser small-size magnetron microwave cavity is lighter.

[0041] Preferably, the pole piece 2 and the connecting column 21 on the pole piece 2 are an integral structure, which has better structural integrity and is easy to process. In the embodiment, the pole piece 2 and the connecting column 21 are both made of aluminum material with a silver-plated outer surface.

[0042] Alternatively, each connecting column 21 is connected to the side wall of the cavity cylinder 1 through a screw, and a threaded hole 210 is formed on the side of the connecting column 21 away from the pole piece 2, and a connecting hole is formed on the side wall of the cylinder body 11, and the screw is threadedly connected to the threaded hole 210 through the connecting hole, so as to realize the connection and fixation of the connecting column 21 and the cylinder body 11, which has strong structural stability and is convenient to disassemble and assemble.

[0043] Further, the passive hydrogen maser small-size magnetron microwave cavity further comprises four filling media 3, each of which is arranged between one pole piece 2 and the cavity cylinder 1 and is connected between the two connecting columns 21 on the pole piece 2. The filling medium 3 is quartz or polytetrafluoroethylene, and preferably is polytetrafluoroethylene, which is convenient to process. By arranging the filling medium 3, the medium in the sealed microwave resonant cavity is increased, which can effectively suppress the magnetic field strength of the modes near the TE011 mode, i.e., there is no other mode within 80 MHz from the center frequency of the TE011 mode, so as to avoid the influence of the transverse magnetic field component on the hydrogen atom transition and further improve the performance of the passive hydrogen maser small-size magnetron microwave cavity.

[0044] Preferably, opposite surfaces of the two connecting posts 21 on each pole piece 2 are provided with mounting grooves, and the two ends of the filling medium 3 are respectively inserted into the two mounting grooves. The filling medium 3 is fixed by the mounting grooves on the two connecting posts 21, and no additional connecting member is needed, so that the overall structure is better.

[0045] The passive hydrogen atomic frequency standard small magnetron microwave cavity provided by the embodiment is simulated and calculated by using HFSS electromagnetic simulation software, and the result shows that the resonance center frequency of the TE011 mode in the passive hydrogen atomic frequency standard small magnetron microwave cavity is close to the hydrogen atomic transition frequency, and there is no other mode within 80MHz from the center frequency of the TE011 mode, which not only meets the frequency performance of the passive hydrogen atomic frequency standard, but also realizes miniaturization and light weight.

[0046] Note that the above are only preferred embodiments of the present application and the technical principles applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, readjustments and substitutions without departing from the scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A passive hydrogen maser compact magnetron microwave cavity, characterized in that, The utility model relates to a microwave cavity, which comprises: a cavity cylinder, in which a sealed microwave resonant cavity is formed, and two coupling rings are arranged on the side wall of the cavity cylinder respectively, the two coupling rings are used for input and output of microwave signals respectively, the outer diameter of the cavity cylinder is 111mm, the inner diameter of the cavity cylinder is 105mm, and the height of the cavity cylinder is 188.5mm; four pole pieces, which are arranged in the form of an arc, the four pole pieces are arranged in a ring in the sealed microwave resonant cavity, a connecting column is arranged on the side of each pole piece away from the center of the ring of the pole pieces, the connecting column is connected to the side wall of the cavity cylinder, the inner diameter of the ring surrounded by the four pole pieces is 61.6mm, the outer diameter of the ring is 67.4mm, the height of the pole piece is 145mm, and the distance between every two adjacent pole pieces is 3.8mm; two connecting columns are arranged on the side of each pole piece away from the center of the ring of the pole pieces, the two connecting columns are arranged opposite to each other along the height direction of the pole piece, and the two ends of the pole piece are flush with the two connecting columns respectively, the pole piece and the connecting column are an integral structure; four filling media, each of which is arranged between a pole piece and the cavity cylinder and is connected between the two connecting columns on the pole piece; mounting grooves are arranged on the opposite sides of the two connecting columns on each pole piece, and the two ends of the filling medium are inserted into the two mounting grooves respectively.

2. The passive hydrogen maser compact magnetron microwave cavity of claim 1, wherein, The filling medium is quartz or polytetrafluoroethylene.

3. The passive hydrogen maser compact magnetron microwave cavity of claim 1, wherein, Each connecting column is connected to the side wall of the cavity cylinder by a screw.

4. The passive hydrogen maser compact magnetron microwave cavity of claim 1, wherein, The cavity cylinder comprises a cylinder body, which is in the form of a hollow cylinder, a first cavity cover and a second cavity cover are detachably sealed at the two ends of the cylinder body respectively, and the sealed microwave resonant cavity is formed between the cylinder body, the first cavity cover and the second cavity cover.

5. The passive hydrogen maser compact magnetron microwave cavity of claim 1, wherein, A heating wire is wound on the outer wall of the cavity cylinder.

6. The passive hydrogen maser compact magnetron microwave cavity of claim 5, wherein, The outer wall of the cavity cylinder is provided with a plurality of accommodation grooves arranged in the form of a spiral, and the heating wire is embedded in the accommodation grooves.

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