A rotary circular waveguide waveguide switch with high power capacity

Abstract

The application discloses a rotary circular waveguide switch with high power capacity and belongs to the technical field of microwave transmission. The structure comprises a microwave stator, a microwave rotor, a microwave transmission channel, a bottom bearing, a rotating shaft, a shaft sealing assembly, a shaft sealing assembly limiting block, a limiting assembly and a choke structure. The circular waveguide switch can realize high isolation and high power capacity between waveguide switch ports without increasing assembly difficulty and implementation difficulty, guaranteeing high reliability, and can realize small insertion loss and low reflection.

Description

Technical Field

[0001] This invention relates to the field of microwave transmission technology, and more specifically to a rotary circular waveguide switch with high power capacity. Background Technology

[0002] To enable the conversion of microwave signals between different channels, microwave switches are inevitably required. Depending on the transmission line type, electromechanical microwave switches are divided into two types: electromechanical coaxial switches and electromechanical waveguide switches. Generally, electromechanical coaxial switches have a wider bandwidth, but they have a high voltage standing wave ratio (VSWR) and high insertion loss, which cannot meet the requirements of precision electronic systems. Electromechanical waveguide switches, due to their low VSWR, low insertion loss, and high power capacity, are increasingly attracting the attention of engineers and system designers and are widely used in radar, electronic countermeasures, measuring instruments, satellite communications, and other fields.

[0003] Rotary waveguide switches rely on the rotation of a microwave rotor within a microwave stator to switch signals between different microwave channels.

Zhao Na, He Fenrong, Kou Mingdong, et al. Design of a high-isolation, low-loss, full-bandwidth electromechanical waveguide switch [C] / / Chinese Institute of Electronics. Proceedings of the 2021 National Microwave and Millimeter Wave Conference (Volume 2). [Publisher unknown], 2021:3.DOI:10.26914 / c.cnkihy.2021.023680.

Wang Jingxin, Niu Zhiyou, Wen Chunhua. Design of a U-band electromechanical waveguide switch [J]. Space Electronics Technology, 2020, 17(03):24-29.

[0004] In the field of high-power microwaves, to reduce the electric field intensity within the waveguide and avoid power breakdown, waveguides with cross-sectional dimensions several times larger than the corresponding operating wavelength are generally used; these are called overmode waveguides. Furthermore, the transmission mode within them is typically either the microwave source operating mode (TM01 mode) or the transmission radiation mode (TE11 mode). Therefore, traditional waveguide switches based on rectangular waveguides cannot be used in the high-power microwave field.

[0005] In summary, there is a need to design a high-performance rotary waveguide switch for use in over-mode circular waveguides to solve the channel selection problem in microwave transmission and to address the limitation of traditional waveguide switches in high-power applications due to their structural constraints. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a rotary over-mode circular waveguide switch with high power capacity. It can achieve high isolation and high power capacity between waveguide switch ports while ensuring high reliability without increasing assembly or implementation difficulty, and also achieves low insertion loss and low reflection.

[0007] The technical solution adopted in this invention is as follows:

[0008] A rotary circular waveguide switch with high power capacity includes a microwave stator, a microwave rotor, a microwave transmission channel, a bottom bearing, a rotating shaft, a shaft sealing assembly, a shaft sealing assembly limit block, and a limit assembly;

[0009] The microwave stator includes a cylindrical switch outer cylinder, a microwave stator sealing cover at the upper end of the switch outer cylinder, and a microwave stator base plate at the lower end; the switch outer cylinder is provided with one circular waveguide input port and two circular waveguide output ports, the input port is located between the two output ports and has a 90° angle with the two output ports; the microwave stator sealing cover is provided with a through hole at the center position;

[0010] The microwave rotor is disposed inside the microwave stator and includes a cylindrical switch inner cylinder, a microwave rotor sealing cover disposed at the upper end of the switch inner cylinder, and a microwave rotor base plate disposed at the lower end.

[0011] The microwave transmission channel is a transmission waveguide installed inside the microwave rotor to achieve a 90° turn in the microwave transmission direction. Its two waveguide ports are located on the inner cylinder of the switch, and the two waveguide ports are respectively aligned with the input port and the output port.

[0012] The bottom bearing is located between the microwave stator base plate and the microwave rotor base plate;

[0013] The lower end of the rotating shaft is fixedly connected to the microwave rotor sealing cover, and the upper end extends into the through hole of the microwave stator sealing cover and is connected to the external drive system. The rotating shaft drives the microwave rotor to rotate under the drive of the external drive system, thereby realizing the relative rotation of the microwave rotor and the microwave stator, and thus switching the output port aligned with the waveguide port of the microwave transmission channel.

[0014] The shaft sealing assembly is a magnetohydrodynamic shaft seal disposed between the rotating shaft and the microwave stator sealing cover, used to achieve dynamic sealing;

[0015] The shaft sealing assembly limiting block is a stepped columnar structure with an internal through hole; the shaft sealing assembly limiting block is located above the shaft sealing assembly and fixed to the microwave stator sealing cover, used to fix the position of the shaft sealing assembly, and the internal through hole is used to provide space for the shaft to connect with the external drive system;

[0016] The limiting component includes a limiting groove disposed on the limiting block of the shaft sealing component and a limiting pointer disposed on the rotating shaft; the limiting pointer can rotate 90° within the limiting groove, and through the matching use of the limiting groove and the limiting pointer, the rotating shaft can only rotate 90°, thereby realizing the switching of the output port.

[0017] Furthermore, the microwave transmission channel includes a first curved waveguide segment, a circular waveguide segment, and a second curved waveguide segment connected in sequence; wherein the first curved waveguide segment and the second curved waveguide segment are curved waveguides with a 45° turn.

[0018] Furthermore, there is a certain gap between the microwave rotor and the microwave stator, and the gap is no greater than 2mm.

[0019] Furthermore, the inner wall of the switch outer cylinder is provided with a choke structure; the choke structure includes a first annular choke groove; the first annular choke groove is concentrically arranged with the input port or the output port, the spacing is a quarter wavelength, and the groove depth is a quarter wavelength.

[0020] Furthermore, the choke structure also includes an annular matching gap concentrically arranged with the first annular choke groove; the inner radius of the annular matching gap is the same as the radius of the input port or output port, the outer radius is the same as the inner radius of the first annular choke groove, and the thickness is greater than the gap thickness between the inner cylinder and the outer cylinder of the switch and less than the groove depth of the first annular choke groove.

[0021] Furthermore, the choke structure also includes a second annular choke groove arranged concentrically with the first annular choke groove; the distance between the second annular choke groove and the first annular choke groove is one-quarter wavelength, and the groove depth is one-quarter wavelength.

[0022] Furthermore, the limiting component also includes positioning screw holes disposed in the limiting block and the limiting pointer of the shaft seal component, and positioning screws that match the positioning screw holes; by inserting the positioning screws into the positioning screw holes, the relative positions of the limiting block and the limiting pointer of the shaft seal component are fixed, thereby aligning the waveguide port of the microwave transmission channel with the input port and the output port.

[0023] Furthermore, the edges of the annular matching gap are rounded to further increase the power capacity.

[0024] Furthermore, annular grooves for filling sealing rings are provided between the inner cylinder of the switch and the rotor sealing cover and the rotor base plate, as well as between the outer cylinder of the switch and the stator sealing cover and the rotor base plate.

[0025] Furthermore, the microwave rotor sealing cover is provided with a shaft groove for mounting the shaft.

[0026] The advantages of this invention compared to the prior art are:

[0027] (1) The present invention is a single-pole double-throw switch, which performs the function of two switches with one switch, thus greatly reducing the overall cost of the microwave system.

[0028] (2) This invention is applicable to high power levels, up to the GW level.

[0029] (3) The microwave rotor and microwave stator used in this invention have a gap between them, which enables contactless rotation of the microwave rotor and improves the service life of the microwave rotor. At the same time, the rotation driving method has the advantages of being easier to drive, having a more compact structure, and having more stable performance compared to linear push-pull.

[0030] (4) The microwave rotor used in this invention is a hollow cylindrical shell formed by combining a switch inner cylinder, a microwave rotor sealing cover and a microwave rotor base plate. The hollow structure greatly reduces the weight of the entire metal system, facilitates the rotation of the microwave rotor, and saves processing costs to the greatest extent.

[0031] (5) By setting multiple choke structures on the microwave stator, the present invention realizes the electrical contact of waveguide transmission and the separation of microwave rotor and microwave stator structure. While ensuring the safe movement gap of waveguide switch, it achieves high isolation of waveguide switch, further improves the power capacity of waveguide switch, and has stable and reliable performance and high safety.

[0032] (6) The present invention achieves the characteristics of low reflection and low insertion loss of waveguide switch by using a microwave transmission channel with a 90° bend; and the bend waveguide of the present invention can be applied to the TM01 mode and TE11 mode of the overmode circular waveguide respectively.

[0033] (7) The present invention uses a limiting component to control rotation and then uses a positioning screw to precisely align and fix it. The limiting block and the limiting pointer of the shaft sealing component are located outside the microwave rotor and microwave stator of the microwave system, which facilitates replacement and maintenance. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall structure of the waveguide switch of the present invention;

[0035] Figure 2 This is a longitudinal cross-sectional view of the waveguide switch of the present invention;

[0036] Figure 3 This is a cross-sectional view of the waveguide switch of the present invention.

[0037] Figure 4 This is a schematic diagram of the microwave stator structure of the present invention;

[0038] Figure 5 This is a schematic diagram of the microwave rotor structure of the present invention;

[0039] Figure 6 This is a schematic diagram of the rotating shaft structure of the present invention;

[0040] Figure 7 This is a schematic diagram of the shaft sealing assembly limiting block and limiting assembly of the present invention;

[0041] Figure 8 This is an exploded view of the waveguide switch of the present invention;

[0042] Figure 9 The S21 curve is shown at the frequency range of 9.5GHz to 9.9GHz when propagating the TM01 mode in this embodiment.

[0043] Figure 10 The S11 and S31 curves are shown at the frequency points from 9.5 GHz to 9.9 GHz when propagating the TM01 mode in this embodiment.

[0044] Figure 11 The S21 curve is shown at the frequency range of 9.5GHz to 9.9GHz when propagating the TE11 mode in this embodiment.

[0045] Figure 12 The S11 and S31 curves are shown at the frequency points from 9.5 GHz to 9.9 GHz when propagating the TE11 mode in this embodiment.

[0046] Figure 13 The electric field distribution at a frequency of 9.7 GHz is shown in the example diagram when propagating the TM01 mode.

[0047] Figure 14 The electric field distribution at 9.7 GHz is shown in the example diagram when the TE11 mode is propagated.

[0048] Explanation of reference numerals in the attached drawings: 1. Microwave stator, 2. Microwave rotor, 3. Shaft, 4. Shaft sealing assembly limiting block, 5. Limiting assembly, 6. Microwave stator sealing cover, 7. Switch outer cylinder, 8. Microwave stator base plate, 9. Microwave rotor sealing cover, 10. Switch inner cylinder, 11. Microwave transmission channel, 12. Microwave rotor base plate, 13. Shaft sealing assembly, 14. Bottom bearing, 15. Sealing ring, 16. Shaft groove, 17. Positioning screw, 18. First port, 19. Second port, 20. Third port, 21. First annular choke groove, 22. Second annular choke groove. Detailed Implementation

[0049] To better illustrate the purpose, advantages, and technical concept of this invention, this paper takes the propagation of high-power microwaves in TM01 and TE11 modes using a C-type single-pole double-throw switch with a diameter of 49.5 mm through-mode circular waveguide in the 9.5–9.9 GHz frequency band as an example to further explain the technical solution of this invention. It should be noted that the specific examples given below are only for illustrative purposes, and the scope of protection of this invention is not limited to what is described below.

[0050] This embodiment provides a rotary circular waveguide switch with high power capacity, such as... Figures 1 to 7 As shown, it includes a microwave stator, a microwave rotor, a microwave transmission channel, a bottom bearing, a rotating shaft, a shaft sealing assembly, a shaft sealing assembly limit block, a limit assembly, and a choke structure.

[0051] The microwave stator includes a cylindrical switch outer cylinder, a microwave stator sealing cover at the upper end of the switch outer cylinder, and a microwave stator base plate at the lower end; an annular groove for filling sealing rings is provided between the switch outer cylinder, the stator sealing cover, and the rotor base plate; a through hole is provided at the center of the microwave stator sealing cover; the switch outer cylinder is provided with a first port, a second port, and a third port, the first port being a circular waveguide input port, and the second and third ports being circular waveguide output ports, with a 90° angle between the input port and the two output ports.

[0052] The microwave rotor, located inside the microwave stator, includes a cylindrical switch inner cylinder, a microwave rotor sealing cover at the upper end of the switch inner cylinder, and a microwave rotor base plate at the lower end. The microwave rotor structure forms a hollow cylindrical shell, which greatly reduces the weight of the entire metal system, facilitates the rotation of the microwave rotor, and saves processing costs to the greatest extent. An annular groove for filling sealing rings is provided between the switch inner cylinder, the rotor sealing cover, and the rotor base plate. A shaft groove is provided on the microwave rotor sealing cover for mounting a shaft.

[0053] The microwave transmission channel is a transmission waveguide installed within the microwave rotor to achieve a 90° turn in the microwave transmission direction. It includes a first curved waveguide section, a circular waveguide section, and a second curved waveguide section connected in sequence; wherein the first and second curved waveguide sections are curved waveguides with a 45° turn. The two waveguide ports of the microwave transmission channel are located on the inner cylinder of the switch, and the two waveguide ports are respectively aligned with the input port and the output port. The microwave transmission channel is designed based on coupled wave theory, enabling high-purity propagation of both TM01 and TE11 modes of the overmode circular waveguide, and features low return loss and GW-level power capacity.

[0054] The bottom bearing is located between the microwave stator base plate and the microwave rotor base plate.

[0055] The lower end of the rotating shaft is fixedly installed to the microwave rotor sealing cover through the rotating shaft groove, and the upper end extends into the through hole of the microwave stator sealing cover and is connected to the external drive system. The rotating shaft drives the microwave rotor to rotate under the drive of the external drive system, thereby realizing the relative rotation of the microwave rotor and the microwave stator, and thus switching the output port aligned with the waveguide port of the microwave transmission channel.

[0056] The shaft sealing assembly includes a magnetohydrodynamic shaft seal disposed between the rotating shaft and the microwave stator sealing cover, thereby achieving a dynamic sealing connection.

[0057] The shaft sealing assembly limiting block is a stepped columnar structure with an internal through hole; the shaft sealing assembly limiting block is located above the shaft sealing assembly and fixed to the microwave stator sealing cover, used to fix the position of the shaft sealing assembly, and the internal through hole is used to provide space for the shaft to connect with the external drive system.

[0058] The limiting component includes a limiting groove on the limiting block of the shaft seal assembly and a limiting pointer on the rotating shaft. It also includes positioning screw holes on the limiting block and the limiting pointer, and positioning screws that match the positioning screw holes. The limiting pointer can rotate 90° within the limiting groove. Through the matching use of the limiting groove and the limiting pointer, the rotating shaft can only rotate 90°, thereby realizing the switching of the output port. Furthermore, by inserting the positioning screw into the positioning screw hole, the relative position of the limiting block and the limiting pointer of the shaft seal assembly is fixed, thereby ensuring that the waveguide port of the microwave transmission channel is precisely aligned with the input port and the output port.

[0059] There is a certain gap between the microwave rotor and the microwave stator, and the gap width is 0.5mm. The gap ensures that the microwave rotor can rotate within the microwave stator. At the same time, by controlling the shape of the gap between the microwave rotor and the microwave stator structure, the resonant cavity structure of the gap connected in parallel with the microwave transmission channel is controlled to prevent resonance.

[0060] The choke structure is disposed on the inner wall of the switch outer cylinder to solve microwave leakage caused by the unavoidable gap between the microwave rotor and the microwave stator. The choke structure includes a first annular choke groove concentric with the input port and the output port, an annular matching gap, and a second annular choke groove. The first annular choke groove is spaced one-quarter wavelength from the input or output port, and its groove depth is one-quarter wavelength. The annular matching gap has the same inner radius as the input or output port, the same outer radius as the first annular choke groove, and a thickness greater than the gap thickness between the switch inner cylinder and the switch outer cylinder but less than the groove depth of the first annular choke groove. The second annular choke groove is spaced one-quarter wavelength from the first annular choke groove, and its groove depth is one-quarter wavelength. By setting the choke structure for impedance matching, quarter-wavelength open-circuit points and half-wavelength short-circuit points are introduced at different locations, ensuring both electrical connection and mechanical disconnection of the structure without disrupting microwave transmission. The edges of the annular matching gap are rounded to further increase power capacity and prevent arcing caused by electrical breakdown under high field strength.

[0061] A C-type waveguide switch enables microwave transmission with specific functions between three ports: when the two waveguide ports of the microwave transmission channel are aligned with the first and second ports respectively, microwaves are transmitted from the first port to the second port via the microwave transmission channel; when the shaft is rotated 90° using an external drive system, i.e., the microwave rotor is controlled to rotate 90°, the two waveguide ports of the microwave transmission channel are aligned with the first and third ports respectively, and microwave transmission from the first port to the third port can be completed in this state. By changing the position of the microwave rotor relative to the microwave stator, the connection and switching between different ports are realized, thereby achieving the single-pole double-throw function.

[0062] Figure 9 The S21 curve for propagating TM01 mode in this embodiment at the frequency range of 9.5GHz to 9.9GHz shows that the propagation of TM01 mode in this embodiment can achieve an insertion loss of less than 0.21dB.

[0063] Figure 10 The S11 and S31 curves at the frequency points of 9.5GHz to 9.9GHz are shown for the propagation of TM01 mode in this embodiment. It can be seen that the propagation of TM01 mode in this embodiment can achieve a high isolation requirement of greater than 87dB and a reflection of less than -27dB.

[0064] Figure 11 The S21 curve for propagating TE11 mode in this embodiment at the frequency points from 9.5GHz to 9.9GHz shows that the propagation of TE11 mode in this embodiment can achieve an insertion loss of less than 0.1dB.

[0065] Figure 12The S11 and S31 curves at the frequency points of 9.5GHz to 9.9GHz are shown for the propagation of TE11 mode in this embodiment. It can be seen that the propagation of TE11 mode in this embodiment can achieve a port isolation of greater than 83dB and a reflection of less than -31dB.

[0066] Figure 13 The image shows the electric field distribution at a frequency of 9.7 GHz when propagating the TM01 mode in an example. Figure 14 The electric field distribution at 9.7 GHz is shown in the example diagram when propagating the TE11 mode. It can be seen that this example achieves a power capacity of GW level when propagating high-power microwaves in both the TM01 and TE11 modes, without increasing the difficulty of processing and assembly or introducing additional non-metallic materials, thus ensuring the high reliability and universality of the waveguide switch design.

[0067] The examples of parameters mentioned above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the design concept of the present invention are within the scope of protection of the present invention.

Claims

1. A rotary circular waveguide waveguide switch with high power capacity, characterized in that, The microwave stator, microwave rotor, microwave transmission channel, bottom bearing, rotating shaft, shaft sealing assembly, shaft sealing assembly limiting block and limiting assembly are provided. The microwave stator comprises a cylindrical switch outer cylinder, a microwave stator sealing cover arranged at the upper end of the switch outer cylinder and a microwave stator bottom plate arranged at the lower end of the switch outer cylinder. The microwave rotor is arranged inside the microwave stator and comprises a cylindrical switch inner cylinder, a microwave rotor sealing cover arranged at the upper end of the switch inner cylinder and a microwave rotor bottom plate arranged at the lower end of the switch inner cylinder. The microwave transmission channel is a transmission waveguide arranged inside the microwave rotor and used for realizing 90° turning of the microwave transmission direction. The bottom bearing is arranged between the microwave stator bottom plate and the microwave rotor bottom plate. The lower end of the rotating shaft is fixedly connected with the microwave rotor sealing cover, and the upper end of the rotating shaft extends into the through hole of the microwave stator sealing cover and is connected with an external driving system. The shaft sealing assembly is a magnetic fluid shaft seal arranged between the rotating shaft and the microwave stator sealing cover and used for realizing dynamic sealing. The shaft sealing assembly limiting block is a stepped columnar structure with a through hole arranged therein. The limiting assembly comprises a limiting slot arranged on the shaft sealing assembly limiting block and a limiting pointer arranged on the rotating shaft.

2. A rotary circular waveguide switch with high power capacity as claimed in claim 1, characterized in that, The limiting pointer can rotate 90° in the limiting slot.

3. A rotary circular waveguide switch with high power capacity according to claim 1 or 2, characterized in that The microwave transmission channel comprises a first bend waveguide section, a circular waveguide section and a second bend waveguide section connected in sequence.

4. A rotary circular waveguide switch with high power capacity as claimed in claim 3, characterized in that, The microwave rotor and the microwave stator have a certain gap, and the gap is not greater than 2 mm.

5. A rotary circular waveguide switch with high power capacity as claimed in claim 4, characterized in that, The inner wall of the switch outer cylinder is provided with a choke structure. The choke structure comprises a first annular choke groove. The first annular choke groove is concentrically arranged with the input port or the output port, the interval is one quarter of the wavelength, and the groove depth is one quarter of the wavelength. The choke structure further comprises an annular matching gap concentrically arranged with the first annular choke groove. The inner radius of the annular matching gap is the same as the radius of the input port or the output port, the outer radius is the same as the inner radius of the first annular choke groove, and the thickness is greater than the gap thickness between the switch inner cylinder and the switch outer cylinder and smaller than the groove depth of the first annular choke groove.

6. A rotary circular waveguide switch with high power capacity as claimed in claim 5, characterized in that, The choke structure further includes a second annular choke groove arranged concentrically with the first annular choke groove; the distance between the second annular choke groove and the first annular choke groove is one-quarter wavelength, and the groove depth is one-quarter wavelength.

7. A rotary circular waveguide switch with high power capacity as claimed in claim 6, characterized in that The edges of the annular matching gap are rounded to further increase power capacity.

8. A rotary circular waveguide switch with high power capacity as claimed in claim 3, wherein, The limiting component also includes positioning screw holes provided in the limiting block and the limiting pointer of the shaft seal component, and positioning screws that match the positioning screw holes; by inserting the positioning screws into the positioning screw holes, the relative positions of the limiting block and the limiting pointer of the shaft seal component are fixed, thereby aligning the waveguide port of the microwave transmission channel with the input port and the output port.

9. A rotary circular waveguide switch with high power capacity as claimed in claim 3, wherein, Annular grooves for filling sealing rings are provided between the inner cylinder of the switch and the rotor sealing cover and the rotor base plate, as well as between the outer cylinder of the switch and the stator sealing cover and the rotor base plate.

10. A rotary circular waveguide switch with high power capacity as claimed in claim 9, characterized in that, The microwave rotor sealing cover is provided with a shaft groove for installing the shaft.

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