Passive type hydrogen atom frequency standard small magnetron microwave cavity

Abstract

The invention relates to the technical field of small magnetron microwave cavities, 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 cylinder and four pole pieces, a closed microwave resonant cavity is formed in the cavity cylinder, the two sides of the side face of the cavity cylinder are respectively provided with a coupling ring, the two coupling rings are respectively used for inputting and outputting microwave signals, 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 188.5 mm; the pole pieces are of an arc-shaped structure, the four pole pieces are annularly arranged in the closed microwave resonant cavity at intervals, a connecting column is arranged on the face, away from the annular center of the multiple pole pieces, of each pole piece in a protruding mode, the connecting columns are connected to the side wall of the cavity cylinder, the inner diameter of a ring defined by the four pole pieces is 61.6 mm, the outer diameter of the ring defined by the four pole pieces is 67.4 mm, the height of the pole pieces is 145 mm, and the distance between every two adjacent pole pieces is 3.8 mm. The mass is light, the size is small, and meanwhile the magnetic field environment requirement of hydrogen atom transition of the passive hydrogen atom frequency standard is met.

Description

Technical Field

[0001] The invention relates to the technical field of small magnetron microwave cavities, in particular to a passive hydrogen atom frequency standard small magnetron microwave cavity. Background Art

[0002] The hydrogen atomic frequency standard is widely used in satellite navigation, aviation, communications and other fields due to its excellent medium- and long-term stability. The passive hydrogen atomic frequency standard is divided into a physical part and a circuit part. The physical part is the core component of the whole machine, and its performance determines the frequency stability of the hydrogen atomic frequency standard. Among them, the microwave cavity, as an important component of the physical part, provides an electromagnetic field environment for the hyperfine energy level transition of hydrogen atoms, so that hydrogen atoms can make transitions from high energy levels to low energy levels. The volume and weight of the microwave cavity are key components that determine the volume and weight of the physical part. At present, the microwave cavity used by the passive hydrogen atomic frequency standard is a magnetron microwave cavity with an internal diameter of 118mm. The physical part accounts for more than 65% of the weight of the passive hydrogen atomic frequency standard, that is, the current passive hydrogen atomic frequency standard is large in size and heavy in weight, which limits its application in small frequency standard scenarios. Summary of the invention

[0003] Based on the above, the purpose of the present invention is to provide a small magnetron microwave cavity for a passive hydrogen atomic frequency standard, which has a light weight and a small volume while meeting the frequency performance of a passive hydrogen atomic frequency standard.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A passive hydrogen atomic frequency standard small magnetron microwave cavity, comprising:

[0006] A cavity tube, wherein a closed microwave resonant cavity is formed in the cavity tube, a coupling ring is respectively arranged on both sides of the side wall of the cavity tube, and the two coupling rings are respectively used for input and output of microwave signals, the outer diameter of the cavity tube is 111 mm, the inner diameter of the cavity tube is 105 mm, and the height is 188.5 mm;

[0007] Four pole pieces, each of which has an arc-shaped structure, and four pole piece spacing rings are arranged in the closed microwave resonant cavity. A connecting column is protruding from one side of each pole piece away from the center of the multiple pole piece rings, and the connecting column is connected to the side wall of the cavity tube. The inner diameter of the ring formed by the four pole pieces is 61.6mm, and the outer diameter is 67.4mm. The height of the pole piece is 145mm, and the spacing between each two adjacent pole pieces is 3.8mm.

[0008] As a preferred solution for a passive hydrogen atomic frequency standard small magnetron microwave cavity, each pole piece is provided with two connecting columns protruding from one side away from the center of the plurality of pole piece rings, and the two connecting columns are arranged opposite to each other at intervals along the height direction of the pole piece and are respectively flush with the two end surfaces of the pole piece.

[0009] As a preferred solution for a passive hydrogen atom frequency standard small magnetron microwave cavity, it also includes:

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

[0011] As a preferred solution for a passive hydrogen atomic frequency standard small magnetron microwave cavity, mounting grooves are provided on opposite surfaces of the two connecting posts on each pole piece, and the two ends of the filling medium are respectively plugged into the two mounting grooves.

[0012] As a preferred solution for a passive hydrogen atom frequency standard small magnetron microwave cavity, the filling medium is quartz or polytetrafluoroethylene.

[0013] As a preferred solution for a passive hydrogen atom frequency standard small magnetron microwave cavity, each of the connecting columns is connected to the side wall of the cavity tube by means of screws.

[0014] As a preferred solution for a passive hydrogen atom frequency standard small magnetron microwave cavity, the pole piece and the connecting column are an integrally formed structure.

[0015] As a preferred solution for a passive hydrogen atomic frequency standard small magnetron microwave cavity, the cavity tube includes a cylinder body, which has a hollow cylindrical structure. The two ends of the cylinder body are respectively detachably sealed with a first cavity cover and a second cavity cover, and the closed microwave resonant cavity is formed between the cylinder body, the first cavity cover and the second cavity cover.

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

[0017] As a preferred solution for a passive hydrogen atom frequency standard small magnetron microwave cavity, the outer wall of the cavity tube is provided with spirally distributed receiving grooves, and the heating wire is embedded in the receiving grooves.

[0018] The beneficial effects of the present invention are:

[0019] The present invention provides a passive hydrogen atom frequency standard small magnetron microwave cavity, which includes a cavity tube and four pole pieces, which are fixed in the cavity tube through connecting columns and have good stability. When in use, a storage bubble containing hydrogen atoms is placed in a closed microwave resonant cavity, and a microwave signal is input through a coupling ring. The electromagnetic wave in the microwave cavity oscillates in the form of a standing wave, forming an electromagnetic field of the TE011 mode whose resonant center frequency is close to the hydrogen atom transition frequency, and the hydrogen atoms in the storage bubble realize F=1, m F =0 and F = 0, m F= 0, the transition center frequency is 1.420405751GHz, which is used as the standard signal of the passive hydrogen atom frequency standard. That is, by properly arranging four pole pieces in a small-sized cavity tube, the small magnetron microwave cavity of the passive hydrogen atom frequency standard can meet the performance of the passive hydrogen atom frequency standard while having a small overall volume and weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0021] Figure 1 is a schematic diagram of the structure of the cavity provided by an embodiment of the present invention;

[0022] Figure 2 is a schematic structural diagram of a cylinder and a pole piece provided in an embodiment of the present invention;

[0023] Figure 3 is a schematic diagram of the structure of the pole piece and the storage bubble provided by an embodiment of the present invention;

[0024] Figure 4 is a schematic diagram of the structure of a pole piece and a filling medium provided in an embodiment of the present invention;

[0025] Figure 5 It is a schematic diagram of the structure of a single pole piece provided in an embodiment of the present invention.

[0026] In the figure:

[0027] 1. Cavity tube; 11. Cylinder body; 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 bubbles. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0034] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0036] In the description of the present embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0037] like Figures 1 to 5As shown, this embodiment provides a passive hydrogen atomic frequency standard small magnetron microwave cavity, which includes a cavity tube 1 and four pole pieces 2. A closed microwave resonant cavity is formed in the cavity tube 1. A coupling ring 5 is respectively arranged on both sides of the side wall of the cavity tube 1. 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 an arc structure, and four pole pieces 2 are arranged in a ring in the closed microwave resonant cavity. A connecting column 21 is convexly arranged on a side of each pole piece 2 away from the center of the multiple pole pieces 2. The connecting column 21 is connected to the side wall of the cavity tube 1. The inner diameter of the ring formed by the four pole pieces 2 is 61.6 mm, the outer diameter is 67.4 mm, the height of the pole piece 2 is 145 mm, and the spacing between each two adjacent pole pieces 2 is 3.8 mm. The pole piece 2 is fixed in the cavity tube 1 by the connecting column 21, and has good stability. When in use, the storage bubble 100 containing hydrogen atoms is placed in a closed microwave resonant cavity, and a microwave signal is input through the coupling ring 5. The electromagnetic wave in the microwave cavity oscillates in the form of a standing wave, forming an electromagnetic field of the TE011 mode whose resonant center frequency is close to the transition frequency of the hydrogen atoms. The hydrogen atoms in the storage bubble 100 realize F=1, m F =0 and F = 0, m F =0, the transition center frequency is 1.420405751GHz, as the standard signal of the passive hydrogen atom frequency standard, the microwave signal coupled out of the magnetron microwave cavity carries the frequency difference information, and after being processed by the external circuit part, the crystal oscillator frequency can be locked on the hydrogen atom transition frequency, and a high-stability signal can be output. That is, by reasonably arranging four pole pieces 2 in the small-sized cavity tube 1, the passive hydrogen atom frequency standard small magnetron microwave cavity has a small overall volume and weight while meeting the performance of the passive hydrogen atom frequency standard, and the volume of the magnetron microwave cavity in the prior art is reduced by 21%.

[0038] Specifically, the cavity tube 1 includes a cylinder 11, which is a hollow cylindrical structure. The two ends of the cylinder 11 are detachably sealed with a first cavity cover 12 and a second cavity cover 13, respectively. A closed microwave resonant cavity is formed between the cylinder 11, the first cavity cover 12 and the second cavity cover 13. The detachability of the first cavity cover 12 and the second cavity cover 13 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 surfaces of the cylinder 11 by bolts, for example, respectively, with high connection stability, convenient disassembly and assembly, and low cost.

[0039] More specifically, a heating wire 4 is wound around the outside of the cavity tube 1, and the heating wire 4 is specifically wound around the outer peripheral wall of the cylinder 11, which is used for temperature control of the microwave cavity so that its resonant frequency is not affected by the ambient temperature. Preferably, the outer wall of the cavity tube 1, that is, the outside of the cylinder 11, is provided with a spirally distributed receiving groove 110, and the heating wire 4 is embedded in the receiving groove 110, which improves the appearance and neatness of the cylinder 11, and the receiving groove 110 can limit the heating wire 4, avoid displacement and slippage of the heating wire 4, and improve the stability and reliability of use. Among them, the cross-section of the receiving groove 110 is U-shaped or arc-shaped, which is specifically set according to actual needs. For example, when the cross-section of the receiving groove 110 is U-shaped, the depth and width are both 1.2 mm, and the spiral is distributed on the outer surface of the cylinder 11 for 19 turns.

[0040] In this embodiment, two connecting posts 21 are convexly provided on one side of each pole piece 2 away from the center of the ring of multiple pole pieces 2. The two connecting posts 21 are arranged opposite to each other along the height direction of the pole piece 2 and are flush with the two end surfaces of the pole piece 2. Under the above structure, the connection stability between each pole piece 2 and the cavity tube 1 is better, and it is not easy to have position displacement or jitter, so that the reliability of the use of the passive hydrogen atomic frequency standard small magnetron microwave cavity is better. Among them, each connecting post 21 is 25mm in length, 10mm in width, and 28mm in height, which ensures that the connection stability of the pole piece 2 is better while occupying less space and being lighter, thereby ensuring that the overall weight of the passive hydrogen atomic frequency standard small magnetron microwave cavity is lighter.

[0041] Preferably, the pole piece 2 and the connecting post 21 on the pole piece 2 are an integrally formed structure, which has good structural integrity and is easy to process. In this embodiment, the pole piece 2 and the connecting post 21 are both made of aluminum with silver-plated outer surfaces.

[0042] Optionally, each connecting column 21 is connected to the side wall of the cavity tube 1 by a screw, a threaded hole 210 is opened on the side of the connecting column 21 away from the pole piece 2, and a connecting hole is opened on the side wall of the cylinder 11. The screw passes through the connecting hole and is threadedly connected to the threaded hole 210 to achieve the connection and fixation between the connecting column 21 and the cylinder 11. The structure has strong stability and is easy to disassemble and assemble.

[0043] Furthermore, the passive hydrogen atom frequency standard small magnetron microwave cavity also includes four filling media 3, each of which is arranged between a pole piece 2 and the cavity tube 1, and connected between two connecting pillars 21 on a pole piece 2. The filling medium 3 is quartz or polytetrafluoroethylene, preferably polytetrafluoroethylene, which is easy to process. By setting the filling medium 3, the medium in the closed microwave resonant cavity is increased, and the magnetic field strength of the mode near the TE011 mode can be effectively suppressed, that is, there can be no other modes within 80MHz of the center frequency of the TE011 mode, avoiding the transverse magnetic field component from affecting the hydrogen atom transition, and further improving the performance of the passive hydrogen atom frequency standard small magnetron microwave cavity.

[0044] Preferably, mounting grooves are provided on the opposite sides of the two connecting posts 21 on each pole piece 2, and the two ends of the filling medium 3 are respectively inserted into the two mounting grooves. The filling medium 3 is fixed and limited by the mounting grooves on the two connecting posts 21, without the need for additional connectors, so that the structural integrity is better.

[0045] The passive hydrogen atom frequency standard small magnetron microwave cavity provided in this embodiment is simulated and calculated by HFSS electromagnetic simulation software. The results show that the resonant center frequency of the TE011 mode in the passive hydrogen atom frequency standard small magnetron microwave cavity is close to the hydrogen atom transition frequency, and there is no other mode within 80 MHz of the TE011 mode center frequency, which not only meets the frequency performance of the passive hydrogen atom frequency standard, but also achieves miniaturization and lightweight.

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

Claims

1. A passive hydrogen atom frequency standard small magnetron microwave cavity, characterized in that: include: A cavity tube, wherein a closed microwave resonant cavity is formed in the cavity tube, a coupling ring is respectively arranged on both sides of the side wall of the cavity tube, and the two coupling rings are respectively used for input and output of microwave signals, the outer diameter of the cavity tube is 111 mm, the inner diameter of the cavity tube is 105 mm, and the height is 188.5 mm; Four pole pieces, each of which has an arc-shaped structure, and four pole piece spacing rings are arranged in the closed microwave resonant cavity. A connecting column is protruding from one side of each pole piece away from the center of the multiple pole piece rings, and the connecting column is connected to the side wall of the cavity tube. The inner diameter of the ring formed by the four pole pieces is 61.6mm, and the outer diameter is 67.4mm. The height of the pole piece is 145mm, and the spacing between each two adjacent pole pieces is 3.8mm.

2. The passive hydrogen atomic frequency standard small magnetron microwave cavity according to claim 1 is characterized in that: Two connecting columns are protruding from one side of each pole piece away from the center of the plurality of pole pieces in a ring arrangement. The two connecting columns are arranged opposite to each other at intervals along the height direction of the pole piece and are respectively flush with the two end surfaces of the pole piece.

3. The passive hydrogen atomic frequency standard small magnetron microwave cavity according to claim 2 is characterized in that: Also includes: Four filling media, each of which is arranged between one of the pole pieces and the cavity tube, and connected between two of the connecting posts on one of the pole pieces.

4. The passive hydrogen atom frequency standard small magnetron microwave cavity according to claim 3 is characterized in that: Mounting grooves are provided on opposite surfaces of the two connecting posts on each of the pole pieces, and two ends of the filling medium are respectively plugged into the two mounting grooves.

5. The passive hydrogen atomic frequency standard small magnetron microwave cavity according to claim 3 is characterized in that: The filling medium is quartz or polytetrafluoroethylene.

6. The passive hydrogen atom frequency standard small magnetron microwave cavity according to claim 2, characterized in that: Each of the connecting columns is connected to the side wall of the cavity tube by means of screws.

7. The passive hydrogen atomic frequency standard small magnetron microwave cavity according to claim 2, characterized in that: The pole piece and the connecting column are an integrally formed structure.

8. The passive hydrogen atomic frequency standard small magnetron microwave cavity according to claim 1, characterized in that: The cavity tube comprises a cylinder body, which is a hollow cylindrical structure. Both ends of the cylinder body are detachably sealed with a first cavity cover and a second cavity cover, and the closed microwave resonant cavity is formed between the cylinder body, the first cavity cover and the second cavity cover.

9. The passive hydrogen atomic frequency standard small magnetron microwave cavity according to claim 1, characterized in that: A heating wire is wound around the outer wall of the cavity tube.

10. The passive hydrogen atom frequency standard small magnetron microwave cavity according to claim 9, characterized in that: The outer wall of the cavity tube is provided with a spirally distributed receiving groove, and the heating wire is embedded in the receiving groove.

Images