A waveguide high-power coupler with online adjustable coupling degree

Abstract

A waveguide-type high-power coupler with online adjustable coupling includes a waveguide and a tuning device. The waveguide includes waveguide sidewalls that enclose a waveguide cavity. The waveguide sidewalls have mounting openings located at or near the peak of the microwave wave. The tuning device includes a tuning rod and a moving adjustment mechanism. Because the moving adjustment mechanism can move the tuning rod, changing the depth of the tuning rod's insertion into the waveguide cavity, the coupler can adjust its coupling in real time during operation. This allows for better matching of the power source and the cavity, ultimately ensuring the stable operation of the entire accelerator. Simultaneously, it significantly reduces the difficulty of adjustment, and due to the real-time nature, convenience, and wide range of adjustment, the machining accuracy requirements for the coupler components can be relaxed to some extent. Furthermore, the real-time adjustability of this coupler allows it to be applied to high-frequency accelerating cavities with beam loads of different energies.

Description

Technical Field

[0001] This invention relates to the field of waveguide-type coupling device technology, and specifically to a waveguide-type high-power coupler with online adjustable coupling. Background Technology

[0002] High-power couplers are crucial components of high-frequency systems in particle accelerators. Located between the power source and the high-frequency cavity, their function is to efficiently feed power from the power source into the high-frequency cavity through coupling. Furthermore, because they are directly connected to the high-frequency cavity, they can be considered part of the cavity itself. Based on past experience, high-power couplers are also among the most prone to failure in high-frequency systems. Any malfunction can affect the entire particle accelerator's operation, potentially even causing it to shut down. Troubleshooting these malfunctions requires significant human, material, and financial resources; therefore, research on high-power couplers has always been a key focus in the field of high-frequency microwave accelerators.

[0003] Currently, internationally used high-power couplers are classified into two types according to their structure: coaxial and waveguide. Coaxial high-power couplers have a compact structure, but their power capacity is relatively low and they are prone to arcing; waveguide high-power couplers have a simple design, high power capacity, and are less prone to arcing, so they are widely used in the megawatt-level power range. However, adjusting the coupling degree between waveguide couplers and high-frequency cavities is extremely difficult internationally. The methods either involve machining an aluminum model identical to the actual coupler to determine the final dimensions (Reference 1, Fan Mengxu, Liu Huachang, Li Ahong, et al., Cold Testing and Analysis of Power Couplers for Drift Tube Linear Accelerators in Spallation Neutron Source), or repeatedly machining the coupling holes of the coupler in actual use to determine the final dimensions (Reference 2, Xing Qing Zi, Du Lei, Zheng Shuxin, et al. Tuning and Cold Test of a Four-Vane RFQ with Ramped Inter-Vane Voltage for the Compact Pulsed Hadron Source. Chinese Physics Letters 30.5(2013):052901), or adding a three-column waveguide converter far from the coupler's input port (Reference 3, V. Veshcherevich and S. Belomestnykh. CORRECTION OF THE COUPLING OF CESR RF CAVITIES TO KLYSTRONSUSING THREE-POST). (WAVEGUIDETRANSFORMERS.SRF 020220-02) to achieve coupling adjustment, that is, to adjust the size of the coupling hole by processing or to find a combination of three-column waveguide converters to make the coupling as close as possible to the target value. However, the above three solutions are not only complicated to operate and cost a lot of time and manpower, but also cannot meet the requirements of real-time online adjustment of coupling. That is, under the condition of high power feed coupler and high vacuum sealing, the output power of the power source can be fed into the high-frequency cavity with high efficiency through the coupler by adjusting the tuning device on the coupler. Summary of the Invention

[0004] This invention provides a waveguide-type high-power coupler with online adjustable coupling, which can perform online real-time adjustment of coupling during coupler operation.

[0005] In one embodiment, the present invention provides a waveguide-type high-power coupler with online adjustable coupling, characterized in that it comprises:

[0006] A waveguide configured to transmit microwaves, the waveguide including waveguide sidewalls that enclose a waveguide cavity for the microwaves to pass through, and the waveguide sidewalls having mounting openings located at or near the crest of the microwaves.

[0007] The device includes a tuning device connected to the waveguide via the mounting port. The tuning device includes a tuning rod and a moving adjustment mechanism. The tuning rod extends at least partially into the waveguide cavity. The moving adjustment mechanism is configured to adjust the depth of the tuning rod extending into the waveguide cavity to adjust the coupling degree between the coupler and the waveguide cavity in real time online.

[0008] In one embodiment, the movable adjustment mechanism includes:

[0009] A fixed housing is provided, one end of which is fixedly connected to the mounting port. The fixed housing has a first mounting cavity at one end near the mounting port and a second mounting cavity at the other end along the axial direction of the fixed housing. The first mounting cavity communicates with the second mounting cavity and penetrates the fixed housing along the axial direction.

[0010] A transmission element, one end of which passes sequentially through the second mounting cavity and the first mounting cavity and is connected to the tuning rod;

[0011] The drive element is connected to the fixed housing, and the output end of the drive element extends into the second mounting cavity and is connected to the transmission element, which can drive the transmission element to move so that the tuning rod moves along its axial direction, thereby adjusting the depth of the tuning rod extending into the waveguide cavity.

[0012] In one embodiment, the driving element is a stepper motor, and the transmission element includes a first transmission element and a second transmission element. One end of the first transmission element is fixedly connected to the tuning rod, and the other end is threadedly connected to the second transmission element. The second transmission element is rotatably disposed in the second mounting cavity. The output end of the stepper motor is connected to the second transmission element, which can drive the second transmission element to rotate along its axis, thereby driving the first transmission element to move linearly along its axis, thereby adjusting the depth of the tuning rod inserted into the waveguide cavity.

[0013] In one embodiment, the tuning rod includes a first end near the waveguide cavity and a second end away from the waveguide cavity, the second end having a third mounting cavity, and the second end extending at least partially into the first mounting cavity, and one end of the first transmission element extending into the third mounting cavity and fixedly connected to the tuning rod;

[0014] It also includes an elastic element, one end of which extends into the third mounting cavity and is sealed to the tuning rod, and the other end extends into the first mounting cavity and is sealed to the bottom wall of the first mounting cavity, so as to seal the tuning device and compensate for the movement of the tuning rod. One end of the first transmission element is sealed and sleeved in the elastic element.

[0015] In one embodiment, the tuning rod, the first transmission element, the second transmission element, the elastic element, and the fixed housing are coaxially arranged, and there is a gap between the outer wall of the tuning rod and the inner wall of the mounting port, a gap between the outer wall of the elastic element and the inner wall of the third mounting cavity, and a gap between the outer wall of the second end of the tuning rod and the inner wall of the first mounting cavity, so as to avoid the tuning rod from rubbing against the mounting port and the inner wall of the first mounting cavity when it moves, and to realize high-frequency short circuit under non-physical contact conditions between the tuning rod and the inner wall of the mounting port.

[0016] In one embodiment, a first water return mechanism is further included. The first water return mechanism is configured to allow first water return to pass through in order to reduce the temperature of the tuning device. The first water return mechanism includes a first inlet pipe, a first outlet pipe, and a first spiral pipe. The spiral pipe is spirally disposed inside the tuning rod. The first water return enters from the first inlet pipe, flows through the first spiral pipe, and finally flows out through the first outlet pipe. The interior of the first transmission element is a hollow structure to form the first outlet pipe. The first inlet pipe is disposed inside the first transmission element and is coaxially disposed with the first transmission element.

[0017] In one embodiment, a displacement sensor is further included to monitor the travel of the motion adjustment mechanism.

[0018] In one embodiment, the waveguide sidewall is further provided with:

[0019] An input port, which is used to input microwaves;

[0020] An output port, the output port being used to output microwaves reflected by the tuning rod and the short road surface;

[0021] A vacuum port is connected to a vacuum pumping device to achieve a vacuum inside the waveguide cavity;

[0022] A vacuum monitoring port is provided, which is connected to a vacuum monitoring device to monitor the vacuum level inside the waveguide cavity.

[0023] The center lines of the input port, the output port, and the mounting port are all perpendicular to each other.

[0024] In one embodiment, the size of the input port is larger than the size of the output port.

[0025] In one embodiment, the output port includes:

[0026] The first sidewall encloses and forms an output cavity for the microwave output;

[0027] The first sidewall and the second sidewall surround the first sidewall and form a return water cavity with the first sidewall. The return water cavity is provided with a second return water mechanism, which is configured to allow second return water to pass through in order to reduce the temperature of the output port. The second return water mechanism includes a second inlet pipe and a second outlet pipe. The second inlet pipe and the second outlet pipe are connected and arranged around the first sidewall and the second sidewall. The second return water enters through the second inlet pipe and flows out through the second outlet pipe.

[0028] According to the waveguide-type high-power coupler with online adjustable coupling in the above embodiments, the movable adjustment mechanism can drive the tuning rod to move, changing the depth of the tuning rod extending into the waveguide cavity. This allows the coupler to adjust the coupling in real time during operation, better matching the power source and the cavity, and ultimately ensuring the stable operation of the entire accelerator. At the same time, it greatly reduces the difficulty of adjustment, and due to the real-time, convenient, and wide-range adjustment, the processing accuracy requirements for the coupler components can be relaxed to a certain extent. In addition, the adjustability of this coupler allows it to be applied to high-frequency accelerating cavities with beam loads of different energies. Attached Figure Description

[0029] Figure 1 The location of the high-power coupler within the high-frequency system of the particle accelerator;

[0030] Figure 2 This is a schematic diagram of a waveguide-type high-power coupler with online adjustable coupling.

[0031] Figure 3 The main view of the structure of a waveguide-type high-power coupler with online adjustable coupling.

[0032] Figure 4 for Figure 3 Schematic diagram of the AA section structure;

[0033] Figure 5 A top view of the structure of a waveguide-type high-power coupler with online adjustable coupling.

[0034] Figure 6 This is a schematic diagram of a waveguide structure;

[0035] Figure 7 This is a schematic diagram of the structure of one embodiment of the tuning device;

[0036] Figure 8 This is a cross-sectional view of a high-power coupler;

[0037] Figure 9 A schematic diagram showing the optimized dimensions of the tuning device;

[0038] Figure 10 This is a high-frequency electric field distribution diagram of a high-power coupler;

[0039] Figure 11 This is a high-frequency magnetic field distribution diagram of a high-power coupler;

[0040] Figure 12 A graph showing the relationship between the insertion depth of the tuning rod and the degree of coupling.

[0041] Wherein: 100, waveguide; 110, waveguide sidewall; 112, output port; 1121, first sidewall; 1122, second sidewall; 114, vacuum extraction port; 115, vacuum monitoring port; 116, mounting port; 120, waveguide cavity.

[0042] 200. Tuning device; 210. Tuning rod; 2121. Third mounting cavity; 220. Moving adjustment mechanism; 221. Fixed housing; 2211. First mounting cavity; 2212. Second mounting cavity; 222. Driving element; 223. Transmission element; 2231. First transmission element; 2232. Second transmission element; 230. Displacement sensor; 240. Elastic element; 250. First water return mechanism;

[0043] 300. Second water return mechanism; 310. Second water inlet pipe; 320. Second water outlet pipe. Detailed Implementation

[0044] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments. Similar elements in different embodiments are referred to by related similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the present application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to the present application are not shown or described in the specification. This is to avoid obscuring the core parts of the present application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0045] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments, and the operational steps involved in each embodiment can also be rearranged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the specification and drawings are only for clearly describing a particular embodiment and do not imply that they represent the necessary components and / or order.

[0046] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0047] refer to Figure 1 High-power couplers are used between power sources and high-frequency cavities and are one of the important devices in the high-frequency system of particle accelerators. They can couple the microwaves output from the power source and feed them into the high-frequency cavity with high efficiency. For accelerators, on the one hand, the accelerating cavity may operate in different states according to actual needs. For example, the beam-scattering cavity of the spallation neutron source needs to operate in multiple states such as acceleration, drift and deceleration. Its beam load is different, and the required coupling degree is also different. On the other hand, some accelerating cavities may be used for failure compensation, and their operating electric field may be much higher than the original design. If the beam load remains unchanged, the coupling degree of the coupler also needs to be adjustable.

[0048] This application provides a waveguide-type high-power coupler with online adjustable coupling, which enables the coupler to adjust the coupling in real time during operation, thereby better matching the power source and the cavity and ultimately ensuring the stable operation of the entire accelerator. At the same time, it greatly reduces the difficulty of adjustment, and due to the real-time, convenient and wide-range adjustment, the processing accuracy requirements of the coupler component can be relaxed to a certain extent. In addition, the adjustability of the coupler makes it applicable to high-frequency accelerating cavities with beam loads of different energies.

[0049] refer to Figure 2-9 The coupler includes a waveguide 100 and a tuning device 200, the waveguide 100 being configured to transmit microwaves, and the tuning device 200 being coupled to the waveguide 100.

[0050] refer to Figure 3-6 The waveguide 100 includes a waveguide sidewall 110, which encloses a waveguide cavity 120 for the microwave to pass through. The waveguide sidewall 110 is provided with a mounting port 116 in the region of the microwave at or near the peak of the wave, and the mounting port 116 is used for coupling connection with the tuning device 200.

[0051] Furthermore, the waveguide 100 is a rectangular waveguide, which includes six waveguide sidewalls 110. The inner wall of one of the waveguide sidewalls 110 forms a short surface, and the inner walls of the remaining waveguide sidewalls 110 form a high-frequency surface that contacts the microwave, so that the tuning device 200 and the waveguide sidewalls 110 are in high-frequency contact.

[0052] Furthermore, the waveguide sidewall 110 is also provided with an input port, an output port 112, a vacuum extraction port 114, and a vacuum monitoring port 115. The input port is used to input microwaves and is sealed to the power source. The input port is arranged parallel to the short surface. The output port 112 is used to output microwaves reflected by the tuning device 200 and the short surface. The vacuum extraction port 114 is connected to a vacuum pumping device to achieve a vacuum inside the waveguide cavity 120. The vacuum detection port 115 is connected to a vacuum monitoring device to monitor the vacuum level inside the waveguide cavity 120. The degree of vacuum pumping is adjusted by the detection data of the vacuum detection port 115 to ensure that the inside of the coupler is in a vacuum-sealed state.

[0053] Furthermore, the vacuum detection port 115 is positioned close to the mounting port 116, while the vacuum extraction port 114 is positioned away from the mounting port 116 to avoid airflow disturbing the microwaves during vacuuming and affecting microwave transmission. At the same time, since the mounting port 116 is the main coupling position, it is necessary to ensure the vacuum level of this position and the tuning device 200. Therefore, the vacuum detection port 115 is positioned close to the mounting port 116, which is close to the tuning device 200.

[0054] Furthermore, the centerlines of the input port, the output port 112, and the mounting port 116 are all perpendicular to each other, that is, the input port, the output port 112, and the mounting port 116 are set on different waveguide sidewalls 110. The microwave enters the waveguide cavity 120 through the input port, and after passing through the tuning device 200 and the short-circuit surface, the transmission direction changes by 90°, and is output through the output port 112, and finally fed into the high-frequency cavity to meet the needs of establishing an electromagnetic field and beam acceleration.

[0055] Specifically, taking the waveguide sidewall 110 where the input port is located as the front, the short surface is the corresponding back, the mounting port 116 and the vacuum detection port 115 are located on the right side, the vacuum extraction port 114 is located on the left side, and the output port 112 is located on the top.

[0056] Furthermore, in order to ensure the safety of forward power transmission, avoid the heat generation problem caused by high power flow density, and ensure connection with universal transmission waveguide, the size of the input port is larger than the size of the output port 112.

[0057] refer to Figure 5The tuning device 200 includes a cylindrical tuning rod 210, which has a choke structure inside. The tuning rod 210 is at least partially inserted into the waveguide cavity 120. By changing the depth of the tuning rod 210 in the waveguide cavity 120, the coupling degree between the coupler and the high-frequency cavity can be changed, thereby ultimately realizing the online adjustable coupling degree of the high-power coupler.

[0058] like Figure 8 As shown in the figure, Insert_l represents the insertion depth of the tuning rod 210, and the coupling degree can be adjusted by changing the size of Insert_l.

[0059] In other possible implementations, different sizes of tuning rods 210 can be designed and fabricated, along with corresponding matching waveguides 100, to form couplers with different coupling degrees. Alternatively, multiple coupling holes matching different sizes of tuning rods 210 can be fabricated on the same waveguide 100, allowing adjustment of the coupling degree using the corresponding tuning rod 210. This method requires shutting down the operating equipment and may involve exposure to the atmosphere, undoubtedly consuming significant manpower, material resources, and financial resources. Furthermore, the fabrication of different sizes of tuning rods 210 and corresponding waveguides 100 increases the design and fabrication difficulty and the cost of the coupler. Additionally, the replacement and installation of the tuning rods 210 require estimation based on experience, which undoubtedly increases installation errors, resulting in coupling degree errors and affecting equipment operation.

[0060] Unlike the above technical solutions, refer to Figure 3 and 4 The tuning device 200 also includes a movable adjustment mechanism 220, which is configured to adjust the depth of the tuning rod 210 extending into the waveguide cavity 120, so as to realize real-time online adjustment of the coupling degree of the coupler during device operation.

[0061] Furthermore, the movable adjustment mechanism 220 includes a fixed housing 221, a driving element 222, and a transmission element 223. One end of the fixed housing 221 is fixedly connected to the mounting port 116. The fixed housing 221 has a first mounting cavity 2211 at one end near the mounting port 116 and a second mounting cavity 2212 at the other end along the axial direction of the fixed housing 221. The first mounting cavity 2211 communicates with the second mounting cavity 2212 and passes through the fixed housing 221 along the axial direction. One end of the transmission element 223 passes through the second mounting cavity 2212 and the first mounting cavity 2211 in sequence and is connected to the tuning rod 210. The driving element 222 is connected to the fixed housing 221, and the output end of the driving element 222 extends into the second mounting cavity 2212 and is connected to the transmission element 223, which can drive the transmission element 223 to move, so as to realize the movement of the tuning rod 210 along its axis, thereby adjusting the depth of the tuning rod 210 into the waveguide cavity 120.

[0062] Furthermore, the inner diameter of the first mounting cavity 2211 is larger than that of the second mounting cavity 2212, forming a roughly T-shaped structure, so as to have sufficient internal mounting space and reduce the overall space occupied.

[0063] In a possible implementation, the mounting port 116 is connected to the fixed housing 221 via a flange.

[0064] Furthermore, the fixed housing 221 is made of stainless steel, the second transmission element 2232 is made of brass, and the waveguide 100 is also made of stainless steel to meet the strength requirements of the equipment; at the same time, the fixed housing 221 and the waveguide sidewall 110 are electrically connected through metal conduction.

[0065] In a possible implementation, the driving element 222 is a stepper motor, and the transmission element 223 includes a first transmission element 2231 and a second transmission element 2232. One end of the first transmission element 2231 is fixedly connected to the tuning rod 210, and the other end is threadedly connected to the second transmission element 2232. The second transmission element 2232 is rotatably disposed in the second mounting cavity 2. The output end of the stepper motor is connected to the second transmission element 2232, which can drive the second transmission element 2232 to rotate along its axis, thereby driving the first transmission element 2231 to move linearly along its axis, thereby adjusting the depth of the tuning rod 210 inserted into the waveguide cavity 120.

[0066] It is understood that the movement of the tuning rod 210 into the waveguide cavity 120 is a linear motion. Therefore, other devices that can drive the tuning rod 210 to make linear motion can also be used as driving devices, such as linear motors or hydraulic cylinders.

[0067] Furthermore, the tuning rod 210 includes a first end near the waveguide cavity 120 and a second end away from the waveguide cavity 120. The second end has a third mounting cavity 2121, and the second end extends at least partially into the first mounting cavity 2211. One end of the first transmission element 2231 extends into the third mounting cavity 2121 and is fixedly connected to the tuning rod 210. It also includes an elastic element 240. One end of the elastic element 240 extends into the third mounting cavity 2121 and is sealed to the tuning rod 210. The other end extends into the first mounting cavity 2211 and is sealed to the bottom wall of the first mounting cavity 2211 (the contact surface between the first mounting cavity 2211 and the second mounting cavity 2212), so as to seal the tuning device 200 and compensate for the movement of the tuning rod 210. One end of the first transmission element 2231 is sealed and sleeved in the elastic element 240.

[0068] Based on the above layout structure, the local structure in which the tuning rod 210, the elastic element 240, and the first transmission element 2231 overlap in multiple layers in the radial direction shortens the axial length of the entire tuning device 200, and the impedance of this local structure changes slowly during the adjustment process, making the adjustment process more stable.

[0069] Furthermore, the elastic element 240 compensates for the movement of the tuning rod 210 by utilizing its stretching and contraction properties. At the same time, the setting of the elastic element 240 can also ensure the vacuum requirement inside the tuning device 200, so that the vacuum outside the tuning rod 210 is isolated from the atmosphere inside it.

[0070] In one possible implementation, the elastic element 240 is a metal bellows.

[0071] To ensure better implementation of the adjustment function, a high-frequency short circuit is formed between the tuning device 200 and the waveguide 100. The tuning rod 210, the first transmission element 2231, the second transmission element 2232, the elastic element 240, and the fixed housing 221 are coaxially arranged. The dimensions of the tuning rod 210, the first transmission element 2231, the second transmission element 2232, and the fixed housing 221 can be optimized according to the following formula to achieve high-frequency contact between the tuning rod 210 and the moving adjustment mechanism 220 under non-contact conditions, thereby achieving power coupling. The specific dimensions are as follows: Figure 9 As shown, according to the circuit principle:

[0072] Characteristic impedance of coaxial structure: Z c1 =60*ln(D1 / d1)

[0073] Z c2 =60*ln(D² / d²)

[0074] Input impedance: Z 12 =j*Z c2 *tan(β*l2)

[0075] Z in =(Z 12 +j*Z c1 *tan(β·l1)) / (Z c1 +j*Z 12 *tan(β·l1))*Z c1

[0076] Where the wave number is: β=2*π*f / 3e 8 By optimizing the diameters D1 (diameter of mounting port 116), d1 (diameter of tuning rod 210), D2 (inner wall diameter of third mounting cavity 2121), d2 (diameter of bellows), and the lengths l1 (length of first mounting cavity 2211 along the axial direction) and l2 (length of third mounting cavity 2121 along the axial direction) of the coaxial structure, Z can be achieved. in ≈0, meaning the input impedance approaches 0, which means that a high-frequency short-circuit function is achieved between the tuning device 200 and the waveguide sidewall 110.

[0077] On the other hand, the above-mentioned size design can shorten the size of the tuning rod 210, providing space for the installation of the elastic element 240 without changing the space occupied by the entire tuning device 200.

[0078] Meanwhile, in previous solutions, since the coupler is made of metal, the tuning rod 210 will rub against the inner wall of the mounting port 116 during the movement of the tuning rod 210, which will cause arcing, resulting in equipment failure and failure to achieve power coupling.

[0079] To avoid this phenomenon and achieve stable, real-time, and online adjustable coupling, after optimization according to the above dimensions, the first transmission element 2231 serves as the internal support, and the fixed housing 221 serves as the external support. The tuning rod 210 is clearance-fitted with the mounting port 116, and the elastic element 240 is clearance-fitted with the fixed housing 221. The optimal clearance is greater than 0.3, i.e., D1 is greater than d1, and D2 is greater than d2. This ensures high-frequency contact while the tuning rod 210 is non-contactly installed with the mounting port 116. When vacuum and high power pass through, the probability of arcing is greatly reduced. The non-contact installation of the elastic element 240 with the fixed housing 221 ensures that the elastic element 240 can move linearly along the axis relative to the fixed housing 221, facilitating movement and adjustment. This, in turn, stably achieves online adjustable coupling during high-power feeding.

[0080] Furthermore, in order to achieve high power transmission and control heat generation, a copper layer of 90-100um is provided on the inner wall of the waveguide sidewall 110, and a copper layer of 90-100um is also provided on the inner wall of the mounting port 116.

[0081] Furthermore, since the temperature at the tuning rod 210 will rise due to heat generation during the coupling process, affecting the coupling effect, the tuning device 200 also includes a first water return mechanism 250. The first water return mechanism 250 is configured to allow first water return to pass through in order to reduce the temperature of the tuning device 200. The first water return mechanism 250 is disposed inside the tuning rod 210 and the fixed housing 221.

[0082] Specifically, the first water return mechanism 250 includes a first water inlet pipe, a first water outlet pipe, and a first spiral pipe. The first spiral pipe is spirally arranged inside the tuning rod 210. The first water return enters from the first water inlet pipe, flows through the first spiral pipe, and finally flows out through the first water outlet pipe. The first water return carries away the heat inside the tuning device 200, thereby reducing the temperature and ultimately controlling the internal temperature of the tuning device 200.

[0083] To make the structure more compact, the interior of the first transmission element 2231 is hollow to form the first water outlet pipe. The first water inlet pipe is located inside the first transmission element 2231 (that is, the first water outlet pipe) and is coaxially and parallel to the first transmission element 2231 (i.e., the center line coincides). That is, the first transmission element 2231 and the first water inlet pipe form a double-layer structure, and the gap between them forms a channel for the first return water to flow out of the tuning device 200. At the same time, the end of the first transmission element 2231 away from the waveguide 100 is provided with a water outlet. The direction of the water outlet is perpendicular to the center line of the first water inlet pipe and the second water outlet. The water flow direction of the first return water changes by 90° and flows out from the water outlet. The transmission element and the return water mechanism share the same pipe, saving space.

[0084] Furthermore, the first water return mechanism 250 is located inside the tuning device 200 and does not share a weld with the vacuum system, which can effectively reduce the risk of water leakage during actual operation; and the first water return mechanism 250 can move synchronously with the movement of the tuning rod 210.

[0085] In practical implementation, the electromagnetic design and optimization of this high-power coupler require attention to its operating frequency and corresponding coupling degree beta. The initial geometric dimensions of the coupler can be quickly determined by optimizing the geometric dimensions of the coupling port (mounting port 116) in the waveguide and the relative position of the short surface to the coupling port (mounting port 116). Subsequently, the position of the tuning device 200 on the waveguide sidewall 110 and the insertion depth of the tuning rod 210 are optimized to finally determine the design of the coupler. Figure 6and Figure 8 The key geometric dimensions that need to be optimized are given. Figure 6 In the diagram, h represents the height of output port 112, l represents its length, w represents its width, T_D represents the outer diameter of tuning rod 210, and Insert_l represents the insertion depth of tuning rod 210. The optimized high-power coupler has the following electric and magnetic field distributions: Figure 10 , Figure 11 As shown; Figure 12 The curves showing the variation of the coupling degree beta between the high-power coupler and the cavity with the tuner insertion depth are presented. It can be seen that when the Insert_l range is 70mm to 110mm, the coupling degree beta varies between 0.3 and 2.7, effectively achieving online adjustability of the coupling degree, exceeding the design specifications. The impact of adjusting the coupling degree on the cavity frequency is within a controllable range, meeting practical application requirements. Simultaneously, thermal and stress analysis was performed on the coupler using the thermal and stress analysis module in the CST program. Ultimately, the temperature rise and deformation of the coupler under operating conditions meet practical application requirements.

[0086] from Figure 10 and 11 As can be seen, for high-power couplers, the location with the largest electromagnetic field is at the coupling port. Because the electromagnetic field at the output port 112 is large, resulting in significant heat generation, a second water return mechanism 300 is also provided at the output port 112. This second water return mechanism 300 is configured to allow second water return to flow through, thereby reducing the temperature of the output port 112. The second water return mechanism 300 includes a second inlet pipe 310 and a second outlet pipe 320. The second water return enters through the second inlet pipe 310 and flows out through the second outlet pipe 320, thus achieving temperature control at the output port 112.

[0087] Furthermore, the output port 112 is a double-wall structure composed of a first sidewall 1121 and a second sidewall 1122. The first sidewall 1121 encloses and forms an output cavity for microwave output. The second sidewall 1122 surrounds the first sidewall 1121 and forms a return water cavity with the first sidewall 1121. A second return water mechanism 300 is provided in the return water cavity. The second water inlet pipe 310 and the second water outlet pipe 320 are connected and arranged around the return water cavity between the first sidewall 1121 and the second sidewall 1122.

[0088] In this embodiment, the waveguide 100 serves to change the direction of power transmission. After conversion, it cleverly avoids the beam and the waveguide window being visually visible to each other from a spatial angle. The input port and output port 112 are perpendicular. The incident power is reflected by the short surface after being tuned by the tuning device 200 and then output through the output port 112, thereby ensuring the transmission of TE-like waves. At the same time, it integrates the corresponding input port, short surface and output port 112 together. By adjusting the insertion depth Insert_l of the tuning rod 210 relative to the waveguide cavity 120 in the tuning device 200, the coupling degree can be adjusted. By setting the moving adjustment mechanism 220 and the displacement sensor 230, the coupling degree can be adjusted online in real time during the operation of the coupler, and the internal structure of the tuning device 200 meets the functions of vacuum sealing and water cooling.

[0089] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A waveguide type high power coupler whose coupling degree is adjustable on line, characterized by, include: A waveguide configured to transmit megawatt-level power microwaves, the waveguide including waveguide sidewalls that enclose a waveguide cavity for the microwaves to pass through, and the waveguide sidewalls having mounting openings located at or near the crest of the microwaves. A tuning device is coupled to the waveguide via the mounting port. The tuning device includes a tuning rod, an elastic element, and a movement adjustment mechanism. The tuning rod extends at least partially into the waveguide cavity. The movement adjustment mechanism is configured to adjust the depth of the tuning rod's insertion into the waveguide cavity to adjust the coupling degree of the coupler in real time. The elastic element seals the tuning device and compensates for the movement of the tuning rod. A gap exists between the outer wall of the tuning rod and the inner wall of the mounting port to prevent the tuning rod from rubbing against the inner wall of the mounting port during movement, and the input impedance approaches 0 to achieve high-frequency short circuit under non-physical contact conditions between the tuning rod and the inner wall of the mounting port. The movement adjustment mechanism includes a transmission element, comprising a first transmission element and a second transmission element. One end of the first transmission element is fixedly connected to the tuning rod, and one end of the first transmission element is sealed within the elastic element, while the other end is threadedly connected to the second transmission element. The tuning rod, the first transmission element, the second transmission element, and the elastic element are coaxially arranged. The first water return mechanism is configured to allow first water return to pass through in order to reduce the temperature of the tuning device. The first water return mechanism includes a first inlet pipe, a first outlet pipe, and a first spiral pipe. The first spiral pipe is spirally arranged inside the tuning rod. The first water return enters from the first inlet pipe, flows through the first spiral pipe, and finally flows out through the first outlet pipe. The interior of the first transmission element is a hollow structure to form the first outlet pipe. The first inlet pipe is arranged inside the first transmission element and is coaxially arranged with the first transmission element.

2. A waveguide high power coupler with online adjustable coupling degree according to claim 1, characterized in that, The movable adjustment mechanism includes: A fixed housing is provided, one end of which is fixedly connected to the mounting port. The fixed housing has a first mounting cavity at one end near the mounting port and a second mounting cavity at the other end along the axial direction of the fixed housing. The first mounting cavity communicates with the second mounting cavity and penetrates the fixed housing along the axial direction. One end of the transmission element passes through the second mounting cavity and the first mounting cavity in sequence and is connected to the tuning rod; The drive element is connected to the fixed housing, and the output end of the drive element extends into the second mounting cavity and is connected to the transmission element, which can drive the transmission element to move so that the tuning rod moves along its axial direction, thereby adjusting the depth of the tuning rod extending into the waveguide cavity.

3. A waveguide high power coupler with online adjustable coupling degree according to claim 2, characterized in that, The driving element is a stepper motor, and the second transmission element is rotatably disposed in the second mounting cavity. The output end of the stepper motor is connected to the second transmission element, which can drive the second transmission element to rotate along its axis, thereby driving the first transmission element to move linearly along its axis, thereby adjusting the depth of the tuning rod inserted into the waveguide cavity.

4. A waveguide high power coupler with online adjustable coupling degree as claimed in claim 3, wherein, The tuning rod includes a first end close to the waveguide cavity and a second end away from the waveguide cavity. The second end has a third mounting cavity, and the second end extends at least partially into the first mounting cavity. One end of the first transmission element extends into the third mounting cavity and is fixedly connected to the tuning rod. One end of the elastic element extends into the third mounting cavity and is sealed to the tuning rod, while the other end extends into the first mounting cavity and is sealed to the bottom wall of the first mounting cavity.

5. A waveguide high power coupler with online adjustable coupling degree as claimed in claim 4, wherein, The tuning rod, the first transmission element, the second transmission element, the elastic element, and the fixed housing are coaxially arranged. There is a gap between the outer wall of the elastic element and the inner wall of the third mounting cavity, and there is a gap between the outer wall of the second end of the tuning rod and the inner wall of the first mounting cavity, so as to avoid the tuning rod rubbing against the inner wall of the first mounting cavity when it moves.

6. A waveguide-type high-power coupler with online adjustable coupling as described in any one of claims 1-5, characterized in that, It also includes a displacement sensor for monitoring the travel of the moving adjustment mechanism.

7. A waveguide high power coupler with online adjustable coupling degree according to any one of claims 1-5, characterized in that, The waveguide sidewall is also provided with: An input port, which is used to input microwaves; The output port is formed by the inner wall of the waveguide sidewall forming a short surface, and the output port is used to output the microwaves reflected by the tuning rod and the short surface. A vacuum port is connected to a vacuum pumping device to achieve a vacuum inside the waveguide cavity; A vacuum monitoring port is provided, which is connected to a vacuum monitoring device to monitor the vacuum level inside the waveguide cavity. The center lines of the input port, the output port, and the mounting port are all perpendicular to each other.

8. A waveguide high power coupler with online adjustable coupling degree according to claim 7, characterized in that, The size of the input port is larger than the size of the output port.

9. A waveguide high power coupler with online adjustable coupling degree as claimed in claim 7, wherein, The output port includes: The first sidewall encloses and forms an output cavity for the microwave output; The first sidewall and the second sidewall surround the first sidewall and form a return water cavity with the first sidewall. The return water cavity is provided with a second return water mechanism, which is configured to allow second return water to pass through in order to reduce the temperature of the output port. The second return water mechanism includes a second inlet pipe and a second outlet pipe. The second inlet pipe and the second outlet pipe are connected and arranged around the first sidewall and the second sidewall. The second return water enters through the second inlet pipe and flows out through the second outlet pipe.

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