A coaxial frequency-locked phase-locked structure and a magnetron array system formed by the same

Abstract

This invention belongs to the field of microwave source technology in vacuum electronic devices, and particularly relates to a coaxial frequency-locked phase-locked structure and a magnetron array system comprising it. The system includes magnetrons equipped with coaxial cables and at least one coaxial energy coupler. The coaxial energy couplers of adjacent magnetrons are connected by coaxial cables between them. The N+1 magnetrons include at least N coaxial cables, and the electrical parameters such as cable length, impedance, and power capacity can be flexibly selected. N>1 can also be any number. This invention introduces efficient frequency-locking and phase-locking between magnetrons, ensuring phase coherence of the output power between the tubes. This allows the use of a large number of magnetrons in an array to overcome the power capacity limitation of a single tube. It also solves the problem of fixed array configuration and inflexibility in existing frequency-locking and phase-locking hard-connection methods, while maintaining the advantages of high-efficiency frequency-locking and phase-locking. The structure offers high flexibility and efficiency, and the overall system is simple.

Description

Technical Field

[0001] This invention belongs to the field of microwave source technology in vacuum electronic devices, and specifically relates to a coaxial line frequency-locked phase-locked structure and the magnetron array system thereof. Background Technology

[0002] In the fields of microwave and vacuum electronics, the magnetron is a high-efficiency microwave tube that generates high-power ultra-high-frequency oscillations.

[0003] The anode of a modern practical magnetron is a cylinder made of a single piece of metal with many resonant cavities. At the center is a cylindrical cathode electron emitter, and permanent magnet poles are installed at both ends to form a fixed magnetic field. The electron flow emitted by the cylindrical hot cathode is affected by the electric field between the anode and cathode and the external axial constant magnetic field, forming a complex motion trajectory in the interaction space (the space between the cathode and anode), which excites the resonant cavity to generate ultra-high frequency oscillations.

[0004] Magnetrons are mainly used in radar transmitters, microwave ovens, and other high-power ultra-high frequency oscillators. However, when a magnetron wants to output higher power, it will face problems such as reaching the withstand voltage limit, insufficient cathode emission capability, and insufficient heat dissipation. Therefore, a single magnetron, whether it is a coaxial magnetron, a heterocavity magnetron, or a furnace magnetron with a diaphragm belt, cannot increase its power indefinitely due to its own power capacity limit.

[0005] In the development of frequency-locked and phase-locked loop (PLL) technology, magnetron connections have primarily been rigid connections. While rigid connections offer a robust structure, they also have significant drawbacks: the fixed length necessitates advance planning and design of the magnetron's structure to avoid assembly issues. This connection characteristic increases the difficulty of large-scale array configurations and makes equipment maintenance and replacement expensive and challenging. Summary of the Invention

[0006] To overcome the above technical problems, this invention provides a coaxial frequency-locked phase-locked structure and a magnetron array system thereof. It introduces efficient frequency-locking and phase-locking between magnetrons, ensuring phase coherence of the output power between the tubes. This allows the use of a large number of magnetrons in an array to overcome the power capacity limitation of a single tube. It also solves the problem of fixed array configuration and inflexibility in existing hard-connected frequency-locking and phase-locking methods, while maintaining the advantages of high-efficiency frequency-locking and phase-locking. The structure offers high flexibility and efficiency, and the overall system is simple.

[0007] The present invention provides a coaxial frequency-locked phase-locked structure to solve the above technical problems. The structure is characterized by comprising a magnetron with a coaxial cable and at least one coaxial energy coupler, wherein the coaxial energy couplers of two adjacent magnetrons are connected by a coaxial cable located between them; the N+1 magnetrons include at least N coaxial cables; N>1, which can also be a number.

[0008] The magnetron structure directly integrates at least one coaxial power coupler, and external connections only require coaxial cables of appropriate impedance and length. The overall system is simple and easy to assemble and process.

[0009] In this invention, multiple magnetrons utilize this structure to lock the frequency and phase, forming a coherent array with output power, allowing for power combining. The interaction space of the multiple magnetrons is mutually locked and coupled through this structure, and due to reduced reflection and the optimal coaxial cable length, the magnetrons lose very little energy during phase locking.

[0010] Meanwhile, the coaxial cable connection method is very flexible. The relative position of the magnetron and the orientation of the output port are no longer fixed, but can be changed quickly and accurately according to specific needs. The structure has great flexibility and high efficiency. In this invention, this array technology can be applied to frequency locking and phase locking of large-scale magnetrons and for subsequent power synthesis.

[0011] The impedance, power capacity, and length of the coaxial cable are determined by the difference in phase-locked frequency and the magnitude of coupling energy between the magnetrons. Different impedances, power capacities, and lengths are used depending on the difference in phase-locked frequency and the magnitude of coupling energy between the magnetrons. Generally, a coaxial cable consists of a sheath, an outer conductor layer, an insulating dielectric layer, and an inner conductor, from the outside in. Its length can be flexibly adjusted according to the different placement structures between the magnetrons, and different impedances and power capacities can be varied by adjusting the diameter of the outer conductor, the material of the insulating dielectric layer, and the diameter of the inner conductor.

[0012] Furthermore, the magnetron is provided with at least one coaxial energy coupler, and also includes a magnetron cathode, M anode blades, an anode cylinder wall, an output waveguide, and an output coupling slot. The coupling slot couples the microwave energy from the magnetron anode space into the output waveguide. The anode cylinder wall is a hollow cylinder with the magnetron cathode located at the center of the anode cylinder wall. One end of the anode blade is located on the inner circumference, and the other end extends from the center of the anode cylinder wall and is at a certain distance from the magnetron cathode. The anode blades form an interaction space with each other and with the magnetron cathode. The output waveguide is generally a hollow rectangle, connected to the anode cylinder wall through the output coupling slot. The bottom end of the output waveguide is provided with a dielectric window, which can seal the internal space of the magnetron, creating an internal vacuum and external air exchange. Waveguide flanges are provided at both ends of the dielectric window, which are used to connect to the external output. The coaxial energy coupler is located on the anode cylinder wall with an opening extending outward.

[0013] In the optimized scheme, M is 12 chips.

[0014] The coaxial energy coupler includes a conductor coupling ring, an impedance transformation section, a supporting dielectric window, an inner conductor, an outer conductor, and a connecting pin. The inner conductor is located between the outer conductors. The outer conductor is a hollow metal cylinder, while the inner conductor is a solid metal cylinder. One end of the inner conductor, closer to the interaction space of the magnetron, is connected to one end of the conductor coupling ring via an impedance transformation section with a stepped diameter. The other end of the inner conductor, away from the interaction space, is equipped with the connecting pin. The other end of the conductor coupling ring is located on the anode cylinder wall or blades, allowing microwave energy from the anode space to be coupled into the coaxial energy coupler in a certain proportion via electromagnetic coupling. The outer conductor is connected to the anode cylinder wall of the magnetron, with one end also connected at a specific location, and the other end extending away from the interaction space. The inner and outer conductors are connected by a supporting dielectric window. This specific location is the same position where the conductor coupling ring connects to the anode cylinder wall or blades.

[0015] The magnetron includes at least one coaxial energy coupler, which has a structure similar to a coaxial output window. The inner conductor of the coaxial output window is connected to the blade or the inner wall of the anode barrel, while the outer conductor extends directly from the opening in the anode barrel. The inner and outer conductors are supported by a window plate, which isolates the vacuum area inside the magnetron from the outside air.

[0016] In the optimized scheme, the conductor coupling ring is horizontally U-shaped.

[0017] The conductor coupling loop allows the electromagnetic wave field to gradually transform to the impedance transformation section under these boundary conditions. Its end is connected to a certain position on the anode cylinder wall or blade, and forms different shapes to adjust the magnitude of the electromagnetic energy coupled to the outside.

[0018] The specially designed conductor coupling ring is beneficial to the efficiency and stability of phase locking. The conductor coupling ring couples the high-frequency oscillation generated by the magnetron to the coaxial energy coupler. According to different frequency locking and phase locking requirements, the size, diameter, shape, and position of the conductor coupling ring connected to the magnetron need to be precisely calculated and measured to ensure that the required effect can be achieved.

[0019] The connecting pin is located at the center of the inner conductor port, which facilitates connection with a coaxial cable.

[0020] The thickness of the supporting medium window is 2mm, and the main material is sapphire, etc.

[0021] The length of the supporting medium window is determined according to actual needs. Different coaxial cable connection lengths are calculated based on the length and thickness of different supporting medium windows to maintain a high phase-locked loop efficiency.

[0022] In a further optimized version, the impedance transformation segment is an impedance transformation segment with a stepped diameter, where the larger diameter end is connected to the inner conductor and the smaller diameter end is connected to the conductor coupling ring.

[0023] The conductor coupling loop connects impedance transformation sections of different diameters. The specially designed impedance transformation sections reduce the reflection of the coupling energy output from the magnetron used for phase locking to the coaxial line.

[0024] This invention relates to a magnetron array system composed of a coaxial cable frequency-locked phase-locked structure. The impedance of the coaxial cable is matched to the impedance of the coaxial energy coupler. Any coaxial energy coupler of any magnetron is connected to any other magnetron via a coaxial cable. The interaction space of several magnetrons is mutually locked and coupled, thus forming a large-scale frequency-locked phase-locked magnetron array system with a specific topology. When magnetrons of this structure are arranged in a large-scale array, the overall energy utilization rate is very high.

[0025] The specific beneficial effects of this invention are as follows:

[0026] (1) The coaxial power coupler of the magnetron can couple less power and transmit its own signal to another magnetron through the coaxial cable, and can also receive signals from another magnetron. This coaxial power coupler is different from the general output port. The coaxial power coupler and the magnetron have specially designed impedance matching. Different impedance matching brings different coupling effects. For example, if the coupling is heavy at a certain size, more energy will be coupled out from the inside of the magnetron. Thus, without affecting the external load of the magnetron and without affecting the original working state of the magnetron, high-efficiency frequency locking and phase locking can be achieved. That is, after phase locking, the efficiency of the magnetron is almost unchanged, and the phase between the magnetrons remains constant.

[0027] (2) After frequency and phase locking, the high-power microwave phase coherence can be combined to form a large-scale microwave source array. Depending on the coupling distance and array requirements, the coaxial cable can be calculated to the most suitable length. Because the coaxial cable can be bent appropriately and its length can be changed easily, the topology of the large-scale frequency and phase locking array system is more flexible and adaptable to various application scenarios, which is very beneficial to the frequency and phase locking of large-scale arrays.

[0028] (3) Due to the symmetry of the two ends of the coaxial line and the very small difference of the coaxial power coupler itself, the whole system is highly symmetrical. As long as the coaxial cable is of a certain length, they can be replaced with each other. The coaxial power coupler is connected when in use and short-circuited with a short-circuit cap when not in use. At this time, the coaxial power coupler has almost no effect on the magnetron.

[0029] The technology in this invention has a very broad application prospect and has the potential to create a new system for the application of high-power microwave sources. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall system structure of the present invention.

[0031] Figure 2 This is a simplified cross-sectional view of the 12-cavity magnetron (i.e., 12 resonant cavities) with one coaxial energy coupler in this invention.

[0032] Figure 3 This is a schematic diagram of the coaxial energy coupler structure in this invention.

[0033] The diagram shows the following components: 1. Magnetron, 2. Coaxial cable, 1-1. Magnetron cathode, 1-2. Anode blade, 1-3. Anode cylinder wall, 1-4. Coaxial power coupler, 1-5. Output waveguide, 1-6. Output coupling seam, 1-7. Dielectric window, 1-8. Waveguide flange, 1-9. Interaction space, 1-4-1. Supporting dielectric window, 1-4-2. Outer conductor, 1-4-3. Inner conductor, 1-4-4. Conductor impedance transformation section, 1-4-5. Connecting pin, 1-4-6. Conductor coupling ring. Detailed implementation method:

[0034] The technical solution of the present invention will be further described below with reference to specific embodiments. Unless otherwise specified, the structural components and corresponding materials used in the following embodiments can be obtained from conventional commercial channels; unless otherwise specified, the processes employed are conventional processes in the art, and the structures are also conventional structures:

[0035] Example 1

[0036] like Figure 1 As shown, a frequency-locked phase-locked array structure includes magnetrons equipped with coaxial cables and at least one coaxial power coupler. The coaxial power couplers of two adjacent magnetrons are connected by a coaxial cable located between them. The N+1 magnetrons include at least N coaxial cables. N>1, which can also be a number.

[0037] If several coaxial power couplers 1 and coaxial cables 2 are provided, the coaxial power couplers 1-4 are connected by a coaxial cable of a specific length and impedance. The coaxial cable uses different impedances, power capacities, and lengths depending on the difference in phase-locked frequency between the magnetrons and the magnitude of the coupling energy. Generally, the coaxial cable consists of a sheath, an outer conductor layer, an insulating dielectric layer, and an inner conductor, from the outside in. Most of the structure and materials of the coaxial cable are conventional, but parameters affecting coupling capability, such as the diameter of the inner and outer conductors and the dielectric constant of the insulating dielectric layer, can be adjusted and selected according to different phase-locked requirements. Figure 1In the diagram, the coaxial cable forming the central "cross" is 20 cm long, has an impedance of 70 ohms, an inner conductor diameter of 1 mm, an outer conductor diameter of 3 mm, and a dielectric constant of 4. The outer, curved coaxial cable is 35 cm long, has an impedance of 50 ohms, an inner conductor diameter of 1 mm, an outer conductor diameter of 2.5 mm, and a dielectric constant of 3.

[0038] Figure 2 The diagram shows a magnetron structure containing one coaxial energy coupler 1-4. The magnetron includes a cathode 1-1, an anode blade 1-2, an anode cylinder wall 1-3, an output waveguide 1-5, an output coupling slot 1-6, a dielectric window 1-7, and a waveguide flange 1-8. It comprises a magnetron cathode, M anode blades, an anode cylinder wall, an output waveguide, and an output coupling slot. The coupling slot couples the microwave energy from the magnetron anode space to the output waveguide. The anode cylinder wall is a hollow cylinder. The magnetron cathode is located at the center of the anode cylinder wall, and one end of the anode blade is located inside the cylinder wall. On the circumference, the other end extends from the center of the anode cylinder wall and is at a certain distance from the magnetron cathode. Interaction spaces are formed between the anode blades and between them and the magnetron cathode. The output waveguide is generally a hollow rectangle, connected to the anode cylinder wall through an output coupling seam. A dielectric window is located at the bottom of the output waveguide, which seals the internal space of the magnetron, creating a vacuum between the internal space and the external air. Waveguide flanges are located at both ends of the dielectric window, used to connect to external outputs. A coaxial energy coupler is located on the anode cylinder wall, with its opening extending outwards. The flanges connect to the external waveguide, and the dielectric window isolates the vacuum.

[0039] Figure 3 This is a schematic diagram of a coaxial energy coupler. The number of coaxial energy couplers 1-4 is greater than or equal to 1.

[0040] It also includes a 1-4-1 supporting dielectric window for supporting the inner conductor 1-4-3 and the outer conductor 1-4-2. The carefully calculated and shape-optimized conductor coupling ring 1-4-6 and the inner conductor are interconnected with the impedance transformation section 1-4-4. The conductor coupling ring 1-4-6 electromagnetically couples with the high-frequency electromagnetic waves in the interaction space, transmitting the electromagnetic waves without loss through the impedance transformation section 1-4-4 of the inner conductor, the supporting dielectric window 1-4-2, and other structures. The 1-4-5 connecting pin is used to connect with the inner conductor component of the coaxial cable 2, forming a whole with the inner conductor I of the coaxial cable. The signal can be transmitted to a farther distance through the coaxial cable.

[0041] The coaxial energy coupler specifically comprises a conductor coupling ring, an impedance transformation section, a supporting dielectric window, an inner conductor, an outer conductor, and a connecting pin. The inner conductor is located between the outer conductors. One end of the inner conductor, closer to the interaction space of the magnetron, is connected to one end of the conductor coupling ring via an impedance transformation section with a stepped diameter. The other end of the inner conductor, away from the interaction space, has a connecting pin. The other end of the conductor coupling ring is located at a specific position on the anode cylinder wall. The outer conductor is connected to the anode cylinder wall of the magnetron, and one end of the outer conductor is also connected at a specific position—the position where the conductor coupling ring connects to the anode cylinder wall or blades. The other end extends away from the interaction space. The inner and outer conductors are connected via a supporting dielectric window. One end of the inner conductor is connected to the specially designed conductor coupling ring, and the other end is connected to the outer conductor. The center of the inner conductor's port away from the interaction space has a connecting pin. The end of the outer conductor has a small gear-shaped thread.

[0042] Example 2

[0043] In the optimized embodiment, including the content of Embodiment 1, the conductor coupling ring is horizontally U-shaped.

[0044] Example 3

[0045] In a further embodiment, including the content in Embodiment 2, the connecting needle is located at the center of the inner conductor port.

[0046] Example 4

[0047] In a further embodiment, including the content in Embodiment 3, the impedance transformation segment is an impedance transformation segment with a stepped diameter, the larger diameter end is connected to the inner conductor, and the smaller diameter end is connected to the conductor coupling ring.

[0048] The conductor coupling loop connects impedance transformation sections of different diameters. The impedance transformation sections reduce the reflection of the coupling energy output from the magnetron used for phase locking to the coaxial line.

[0049] Example 5

[0050] In a further optimized embodiment, including the content in embodiment 4, the thickness of the supporting medium window is 2mm, and the main material is sapphire, etc.

[0051] The length of the supporting medium window is determined according to actual needs. Different coaxial cable connection lengths are calculated based on the length and thickness of different supporting medium windows to maintain a high phase-locked loop efficiency.

[0052] In this embodiment of the invention, the frequency-locked phase-locked array, through carefully designed coaxial energy couplers 1-4 and coaxial cables 2, connects and couples the magnetrons 1 to form a frequency-locked phase-locked array. This array can arbitrarily expand the magnetron units. Furthermore, due to the flexibility of the coaxial cable, the spatial structure and topological connection structure formed by the magnetrons are flexible and adaptable, allowing the output port to be moved to the desired position as needed. Because the coaxial energy couplers perfectly match the impedance of the magnetrons and the coaxial cable, and the length of the coaxial cable is also calculated, microwave energy reflection is reduced. This allows a portion of the energy from one magnetron to be input into another, and vice versa. When the energy injected by both affects the electric field and electrons in their interaction space, frequency-locking and phase-locking begin. Multiple magnetrons form a unified whole through this structure, and the electric fields of each magnetron are thus tightly coupled, ultimately resulting in all magnetrons outputting the same frequency and phase.

[0053] Because microwave energy loss is very small due to the carefully designed matching structure, the corresponding phase-locked efficiency is also very high, which is a high-efficiency phase-locked technology. Furthermore, due to the ease of connection, the frequency-locked phase-locked array can be flexibly configured. The final output power can be spatially synthesized because of the phase consistency. The equivalent omnidirectional radiation power of the spatially synthesized coherent signal increases with the square of the number of magnetrons.

[0054] For coaxial power couplers, the transmission and coupling of electromagnetic waves vary greatly depending on their structure. Finding the optimal coupling state requires extensive experimental testing and calculations, along with careful impedance and length design of the coaxial cable. An optimized coaxial power coupler design results in less electromagnetic energy loss at this point compared to direct slot coupling.

[0055] The embodiments of the present invention provide the array structures and some parameters of the magnetrons in embodiments 1-5:

[0056] In this invention, the magnetron operates in the S-band under pulsed conditions, with a pulse repetition frequency of 100Hz-200Hz, a pulse width of 1µs-10µs, and operates in π mode. The operating voltage is approximately 50kV, the power is 2MW, and the efficiency is 60-70%. Using the technology described in this invention, the frequency is locked to 3GHz, the phase difference between each magnetron is 1° to 10°, the output power is 1.99MW, and the efficiency remains essentially unchanged.

[0057] The above example is an S-band magnetron, but the structure is not limited to the S-band. By adjusting the structural dimensions, this phase-locked loop structure can be adapted to any band.

[0058] The above embodiments / experimental examples are merely illustrative and not intended to limit the implementation methods. Those skilled in the art will recognize that various variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementation methods. However, obvious variations or modifications derived therefrom remain within the scope of this invention.

Claims

1. A coaxial frequency-locked phase-locked structure, characterized in that: The coaxial cable and the magnetron with at least two coaxial energy couplers are connected through the coaxial cable between them; N+1 magnetrons include at least N coaxial cables; N>1. The coaxial energy coupler includes a conductor coupling ring, an impedance transformation section, a support dielectric window, an inner conductor, an outer conductor and a connecting needle. The inner conductor is located between the outer conductor. The inner conductor is connected with one end of the conductor coupling ring through the impedance transformation section with diameter step change near one end of the magnetron interaction space. The other end of the inner conductor away from the interaction space is provided with a connecting needle. The other end of the conductor coupling ring is arranged on the anode cylinder wall of the magnetron or the blade of the magnetron, so that the microwave energy of the anode space is coupled into the coaxial energy coupler through electromagnetic coupling in a certain proportion. The outer conductor is connected with the anode cylinder wall of the magnetron. One end of the outer conductor is also connected at the same position where the conductor coupling ring and the anode cylinder wall of the magnetron or the blade of the magnetron are connected. The other end of the outer conductor extends away from the interaction space. The inner conductor and the outer conductor are connected through the support dielectric window.

2. A coaxial frequency-locked phase-locked structure according to claim 1, characterized in that: The impedance, power capacity and length of the coaxial cable are determined according to the difference between the phase-locked frequencies of the magnetrons and the coupling energy.

3. A coaxial frequency-locked phase-locked structure as claimed in claim 1, characterized in that: The magnetron is provided with at least two coaxial energy couplers, a magnetron cathode, M anode blades, an anode cylinder wall, an output waveguide and an output coupling slot. The anode cylinder wall is a hollow cylinder. The magnetron cathode is arranged at the center of the anode cylinder wall. One end of the anode blade is arranged on the inner circumference of the anode cylinder wall. The other end extends with the center of the anode cylinder wall as a point and is arranged at a certain distance from the magnetron cathode. The anode blades are arranged at a certain distance from each other and the magnetron cathode to form an interaction space. The output waveguide is connected with the anode cylinder wall through the output coupling slot. The bottom end of the output waveguide is provided with a dielectric window sheet. The two ports of the dielectric window sheet are respectively provided with waveguide flanges. The coaxial energy coupler is arranged on the anode cylinder wall and extends outwardly.

4. A coaxial frequency-locked phase-locked structure as claimed in claim 1, characterized in that: The conductor coupling ring is in a horizontal U shape.

5. A coaxial frequency-locked phase-locked structure as claimed in claim 1, characterized in that: The connecting needle is arranged at the center of the port of the inner conductor.

6. A coaxial frequency-locked phase-locked structure as claimed in claim 1, characterized in that: The impedance transformation section is an impedance transformation section with diameter step change. The large diameter end is connected with the inner conductor. The small diameter end is connected with the conductor coupling ring.

7. The system of claim 1 wherein the magnetron array system is configured as a coaxial line FLL (Frequency Locked Loop) structure. The impedance of the coaxial cable matches the impedance of the coaxial energy coupler. Any coaxial energy coupler of any magnetron is connected through the coaxial cable. The interaction spaces of N+1 magnetrons are locked and coupled with each other, so as to form a large-scale frequency-locked phase-locked magnetron array system with a topological structure.

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