A structure for realizing phase locking of a multi-magnetron array based on a cascaded power division system

Abstract

The application discloses a kind of structures for realizing multiple magnetron array phase-locked based on cascaded power division system, belong to vacuum electronic device field.The structure includes cascaded power division injection module, multiple intercoupling magnetron phase-locked modules;Cascaded power division injection module, including at least one power division injection module;Power division injection module, including solid-state microwave source, first circulator, seed magnetron, power divider;The application utilizes the stable small signal of solid-state microwave source to inject and lock seed magnetron, and the seed magnetron injected and locked is used as new high-power seed source, and then is divided into several microwave injection signals by power divider and is injected into multiple intercoupling magnetron phase-locked modules, and then the synchronization phase-locked of multiple intercoupling magnetron array is realized.The application solves the problem of insufficient injection power provided by solid-state microwave source as injection source and unstable working frequency of oscillator as injection source, and brings more stable and larger power injection signal for injection-locked magnetron array.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of vacuum electron devices, and particularly relates to a structure for realizing phase locking of a multi-magnetron array based on a cascaded power division system. BACKGROUND

[0002] A magnetron is a kind of vacuum electron device that utilizes the interaction between orthogonal electromagnetic fields and electron flow to generate high-power microwave energy. Its core working principle is based on the orthogonal field system composed of a radial applied direct-current high-voltage electric field and an axial strong magnetic field in a highly vacuum annular cavity. The electrons emitted by the cathode are accelerated by the electric field and deflected by the magnetic field, forming a rotating “electron spoke” around the cathode. When the angular velocity of the electron spoke is synchronized with the microwave oscillation of the resonant cavity, the electron kinetic energy is efficiently converted into microwave energy, which is then output through the coupling structure. This unique energy conversion mechanism enables it to achieve kilowatt to megawatt microwave power output in a compact structure.

[0003] The technical development of magnetrons began in the early 20th century, with A.W. Hull inventing the first magnetron configuration in 1921. The real technological breakthrough occurred in 1940, when the J.T. Randall and H.A. Boot team at the University of Birmingham in the UK invented the multi-cavity resonant magnetron, which raised the operating frequency to the microwave band and achieved kilowatt-level power. This invention greatly promoted the performance of radar systems. After World War II, the development in civilian fields led to the successful application of magnetrons in household microwave ovens in the 1960s, realizing a leap from military technology to daily life. In recent years, with the progress of material science and precision manufacturing technology, magnetrons have continued to improve in frequency stability, efficiency, and service life, and have given rise to new structures such as coaxial magnetrons and frequency-tunable magnetrons.

[0004] In application fields, magnetrons exhibit wide applicability. In the field of national defense and security, it is widely used as a core microwave source in shipboard and airborne radar systems and electronic countermeasure equipment; in the field of civil use, household and industrial microwave ovens are the most common applications, with global annual production exceeding one billion; in scientific research, high-power magnetrons are used in particle accelerators, plasma generation, and nuclear fusion experimental devices; in addition, in the fields of medical treatment and industrial heating, magnetrons also provide reliable microwave energy for applications such as tumor hyperthermia, material processing, and food sterilization. This wide range of applications across military, civilian, and scientific research fields fully demonstrates the unique value and irreplaceability of magnetrons as efficient microwave energy sources.

[0005] Nowadays, the development of magnetrons is facing some technical bottlenecks, which limit their further application and performance improvement in the field of high-power microwaves. How to stabilize the operating frequency of magnetrons and improve their output power to meet the actual needs of different application scenarios has become a research hotspot in the field of magnetrons.

[0006] In recent years, magnetrons have been widely used in particle accelerators, directional energy research, and radars. Higher output power can be obtained by forming an array of magnetrons. In 2019, Professor Liu Changjun's team at Sichuan University proposed a new injection-locked magnetron power combining system based on frequency-sweeping phase modulation, which can realize the conversion of a single solid-state source microwave signal into two signals to lock two magnetrons through a power divider (Patent Application No. CN201910591335.8). Since 2021, Professor Meng Lin's team at the University of Electronic Science and Technology of China has conducted in-depth research on the mutual coupling array of magnetrons of different wavebands, and many research results have been published in IEEE Electron Device Letters (DOI: 10.1109 / LED.2025.360190; DOI: 10.1109 / LED.2021.3112563), IEEE Transactions on Microwave Theory and Techniques (DOI: 10.1109 / TMTT.2025.3587017). The above research lays the foundation for cascading power division injection locking of multiple mutual coupling magnetron arrays.

[0007] The current injection locking method mainly uses a solid-state microwave source as a seed source for injection locking, as the solid-state microwave source can provide a frequency-stable and high-spectrum-purity microwave signal. However, the power provided by the solid-state microwave source is extremely limited. Even if a power amplifier is connected to the output end of the solid-state microwave source, the requirement for the power amplifier to obtain higher power output is extremely high, and the cost of the system is also increased. If a magnetron is used as an injection source, it can obtain higher output power (one order of magnitude higher than the power amplified by the power amplifier), but the inherent characteristics of the magnetron as an oscillator cause the operating frequency to drift over time, and the instability of the oscillator as a seed source will have a great impact on the locked oscillator.

[0008] According to the Adler criterion, as the number of phase-locked arrays and the number of magnetrons in each phase-locked array increases, the required injection signal power will be higher. In large-scale magnetron array application scenarios, the power provided by a single solid-state microwave source cannot meet the actual needs of high-power locking signals. Therefore, a new phase-locked technology for magnetron arrays needs to be researched to meet the actual needs of people in large-scale magnetron array application scenarios. SUMMARY

[0009] In order to overcome the problems of insufficient output power of the solid-state microwave source and instability of the oscillator as a seed source, the application proposes a structure of cascaded power division system locking multiple inter-coupled magnetron arrays on the basis of the conventional injection locking technology. The application uses the stable small signal of the solid-state microwave source to injection lock an independently operated magnetron. The injection-locked magnetron can be used as a new high-power seed source. The power divider divides the injection signal into several larger power microwave injection signals, which are injected into multiple inter-coupled magnetron phase locking modules, thereby realizing the synchronous phase locking of multiple inter-coupled magnetron arrays. The cascaded structure solves the problems of insufficient injection power provided by the solid-state microwave source as an injection source and instability of the oscillator as an injection source, and brings more stable and larger power injection signals for the injection-locked magnetron array.

[0010] The technical scheme adopted by the application is as follows:

[0011] A structure for realizing phase locking of multiple magnetron arrays based on a cascaded power division system, characterized in that it comprises a cascaded power division injection module and multiple inter-coupled magnetron phase locking modules.

[0012] The cascaded power division injection module comprises at least one power division injection module.

[0013] The power division injection module comprises a solid-state microwave source, a first circulator, a seed magnetron and a power divider.

[0014] The solid-state microwave source is configured to generate a stable microwave signal with an adjustable wide frequency band range, and inject the signal into the seed magnetron through the first circulator to lock the frequency of the seed magnetron.

[0015] The first circulator is configured to transmit the microwave signal reflected by the seed magnetron to an absorbing load.

[0016] The seed magnetron is configured to generate a frequency-locked high-power microwave signal, and transmit the signal to the power divider.

[0017] The power divider is configured to divide the high-power microwave signal into several paths of microwave injection signals.

[0018] When the cascaded power division injection module comprises only one power division injection module, each path of the microwave injection signal is input into one inter-coupled magnetron phase locking module to lock the signal frequency in the inter-coupled magnetron phase locking module.

[0019] When the cascaded power division injection module comprises at least two power division injection modules, the front-stage power division injection module serves as the microwave source of the rear-stage power division injection module, and is configured to provide a stable microwave signal for the seed magnetron in the rear-stage power division injection module.

[0020] Preferably, the first-stage power-division injection module further comprises a second circulator; the second circulator is arranged between the seed magnetron and the power divider, and is used to transmit the microwave signal reflected by the rear-stage output link to an absorbing load, so as to stabilize the working state of the seed magnetron.

[0021] Preferably, a waveguide-to-coaxial converter is further arranged between the solid-state microwave source and the circulator, and is used to realize efficient conversion of electromagnetic waves between two different transmission media.

[0022] Preferably, the mutual-coupling magnetron phase-locked module comprises M magnetrons and M frequency-locked phase-locked loops; the microwave injection signal is injected into one magnetron through the frequency-locked phase-locked loop, and when M is greater than or equal to 2, a mutual-coupling path is established between all the magnetrons through the frequency-locked phase-locked loop, so as to realize frequency-locked phase locking of the M magnetrons.

[0023] Preferably, the frequency band range of the stable microwave signal generated by the solid-state microwave source is 250 KHz-3000 MHz.

[0024] The present application designs a cascade power-division injection module, which ingeniously combines the stability advantage of the solid-state microwave source with the high-power output advantage of the magnetron; the present application locks a small stable signal output by the solid-state microwave source into an independently working magnetron, and the magnetron after being locked indirectly serves as a high-power seed source, so that a microwave injection signal with greater power and stable frequency is obtained. The microwave injection signal provided by the high-power seed source is distributed to different coupling magnetron phase-locked modules through the power divider. The scheme of the present application can greatly improve the stable injection signal power that can be provided by the injection system (at least 2 orders of magnitude higher than the power directly provided by the solid-state microwave source), and better meets the actual needs of large-scale array engineering applications.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] (1) The present application solves the problem of insufficient power of the solid-state microwave source in the traditional scheme, and meets the high-power locking needs of the large-scale magnetron array. Although the solid-state microwave source can provide a frequency-stable signal, the output power is limited, and even if a power amplifier is matched, it is difficult to meet the demand for high injection power of the large-scale magnetron array (the number of phase-locked arrays and the number of magnetrons in a single array increase), and the traditional scheme requires a very high power amplifier.

[0027] (2) The present application takes into account the signal frequency stability, and avoids the instability defect of the magnetron as a seed source. In the prior art, if the magnetron (oscillator) is directly used as a seed source, although a high-power locking signal can be provided, the seed source magnetron is prone to frequency thermal drift after long-time work, and the instability of the seed source magnetron will affect the stability of the locked magnetron or array.

[0028] (3) The application is suitable for large-scale magnetron array application scenarios, and improves the scalability of the system. The cascaded power division injection module can distribute the signal of the high-power seed source to different magnetrons or intercoupled magnetron arrays through the power divider as needed, supporting flexible expansion of the array size; compared with the small-scale locking capability of the prior art, it is more suitable for large-scale magnetron array locking.

[0029] (4) The application reduces the system cost and complexity, and avoids additional investment in high-specification power amplifiers. To make up for the power shortage of solid-state microwave sources, existing solutions often require high-specification power amplifiers, which not only increase the system cost, but also increase the circuit complexity. The application does not rely on high-specification power amplifiers, but uses the high-power characteristics of the magnetron itself to convert it into a stable high-power seed source through cascaded locking, which not only saves the additional cost of the power amplifier, but also simplifies the circuit structure, improves performance while reducing the cost and complexity of the system. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The structure schematic block diagram for locking the intercoupled magnetron array based on the single-stage cascaded power division injection system in Embodiment 1 is shown in

[0031] Figure 2 The structure schematic block diagram for locking the intercoupled magnetron array based on the multi-stage cascaded power division injection system in Embodiment 2 is shown in DETAILED DESCRIPTION

[0032] In order to more clearly illustrate the purpose, features and advantages of the present application, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0033] Embodiment 1:

[0034] This embodiment provides a structure for realizing multi-magnetron array phase locking based on a single-stage cascaded power division system, as shown in Figure 1 The structure includes a cascaded power division injection module and N intercoupled magnetron phase locking modules.

[0035] The cascaded power division injection module is a single-stage power division injection module, which includes a solid-state microwave source, a first circulator, a second circulator, a seed magnetron, two absorption loads, and a power divider.

[0036] The solid-state microwave source has the characteristics of high integration, strong signal controllability, and wide adjustable frequency band range, and is used to generate a stable microwave signal with an adjustable wide frequency band range and input to port #1 of the first circulator; the frequency band range of the stable microwave signal is 250 KHz-3000 MHz.

[0037] The first circulator and the second circulator are both three-port circulators, including port #1, port #2, and port #3, and microwave signals are sequentially and unidirectionally circulated among the ports.

[0038] The first circulator is configured to inject a stable microwave signal input from the port #1 into the seed magnetron through the port #2, so as to lock the frequency of the seed magnetron, and meanwhile, the microwave signal reflected by the seed magnetron is transmitted to an absorbing load through the port #3.

[0039] The seed magnetron is configured to generate a frequency-locked high-power microwave signal and input the high-power microwave signal into the port #1 of the second circulator. Specifically, when the injected power is not less than -32 dB, the seed magnetron is injection-locked, the operating frequency is dragged to the injection frequency, and the injection-locked seed magnetron is regarded as a high-power seed source with stable operating frequency.

[0040] The second circulator is configured to transmit the high-power microwave signal input from the port #1 to the power divider through the port #2, and transmit the microwave signal reflected by the output link in the subsequent stage to the absorbing load.

[0041] The two absorbing loads are configured to absorb excess microwave energy, stabilize the working state of the system, and prevent the reflected signal from damaging the solid-state microwave source or affecting the originally stable working state of the seed source.

[0042] The power divider is configured to divide the high-power microwave signal into N microwave injection signals, and each microwave injection signal is input into one inter-coupling magnetron phase-locked module, so as to lock the frequency of the signal in the inter-coupling magnetron phase-locked module.

[0043] Optionally, since the port of the solid-state microwave source and the port of the power divider are in the form of coaxial lines, and the port of the circulator is in the form of a waveguide, the different transmission media cannot directly transmit signals. Therefore, a waveguide-coaxial converter is arranged between the solid-state microwave source and the circulator, and a waveguide-coaxial converter is arranged between the power divider and the circulator, so as to realize efficient conversion of electromagnetic waves between the two different transmission media.

[0044] Optionally, the inter-coupling magnetron phase-locked module can be a single magnetron working independently, or a plurality of magnetrons forming an inter-coupling array. The more magnetrons included in the inter-coupling array, the greater the injection power required to lock the array. The high-power injection signal provided by the magnetron as a stable seed source can exactly provide the required frequency-stable high-power injection-locked signal for a plurality of inter-coupling arrays formed by a plurality of magnetrons. When the inter-coupling magnetron phase-locked module is a single magnetron working independently, the microwave injection signal is injection-locked to the magnetron through a frequency-locked phase-locked loop, so as to realize frequency-locked phase of N magnetrons.

[0045] When M magnetrons are contained in the mutual coupling magnetron phase-locked module, M≥2; the microwave injection signal is injected into one magnetron through a frequency-locked phase-locked device, and the mutual coupling paths among all the magnetrons are established through the frequency-locked phase-locked device, so as to realize the frequency-locked phase-locked of the M magnetrons in the same mutual coupling magnetron phase-locked module, and further realize the frequency-locked phase-locked of N M magnetrons.

[0046] Optionally, the main body of the frequency-locked phase-locked device is a rectangular waveguide, and a magnetron insertion port and two coupling ports are arranged on the rectangular waveguide; the coupling ports are used for injection of the microwave injection signal and realization of the interconnection among the magnetrons.

[0047] Embodiment 2:

[0048] In order to better illustrate the technical scheme of the cascade power division system for realizing the phase-locked of the multi-magnetron array, the single-stage cascade structure of embodiment 1 is expanded, and the structure of the application is described in more detail.

[0049] The difference between this embodiment and embodiment 1 is that a multi-stage cascade power division injection module is adopted.

[0050] As shown in Figure 2 , the multi-stage cascade power division injection module in this embodiment includes one first-stage power division injection module, K second-stage power division injection modules, K N mutual coupling magnetron phase-locked modules; that is, on the basis of embodiment 1, K second-stage power division injection modules are added.

[0051] The first-stage power division injection module is the same as the single-stage power division injection module in embodiment 1, and outputs K stable microwave signals.

[0052] Each second-stage power division injection module contains a seed magnetron, a second-stage circulator, an absorbing load, a power divider, and a waveguide-coaxial converter.

[0053] The first-stage power division injection module serves as a power source of the K second-stage power division injection modules, and provides stable microwave signals for the seed magnetrons in the second-stage power division injection modules, so as to lock the frequencies of the seed magnetrons.

[0054] The seed magnetron, the second-stage circulator, the absorbing load, the waveguide-coaxial converter, the power divider, and the connection mode and function of the mutual coupling magnetron phase-locked module are the same as those of the first-stage power division injection module.

[0055] By analogy, when more stages of cascade power division injection modules are needed, the structure and connection mode thereof are the same as those of the second-stage power division injection module, and the microwave source of the former stage is used to provide stable microwave signals for the seed magnetrons in the latter stage.

[0056] Optionally, in the embodiment, if a 10-port power divider is used in the first-stage power division injection module, 10 second-stage power division injection modules can be locked; if a 10-port power divider is used in the second-stage power division injection module, each second-stage power division injection module can provide 10 stable injection signals, i.e., 100 inter-coupled magnetron phase-locked modules can be provided with stable injection signals. While greatly improving the scale of the inter-coupled magnetron phase-locked module, the problem of the limitation of the number of power divider ports on the scale of the back-end magnetron phase-locked module is effectively solved, and the problem of too many power division ports and greatly reduced injection signals caused by the cascade of power dividers at the output end is solved. This is conducive to the phase locking of a larger-scale magnetron array.

[0057] In summary, the embodiment can provide sufficient injection power for multiple inter-coupled magnetron arrays or multiple independently operating magnetrons by introducing the cascade power division injection module, and solves the problems of insufficient output power of the solid-state microwave source and instability caused by the oscillator (magnetron) as a seed source. At the same time, the application can obtain a stable frequency injection signal with larger power at a lower cost, and is particularly suitable for injection locking of large-scale magnetron arrays and multiple single-tube operating magnetron systems. At the same time, the application has a simple structure and is easy to implement, and has certain practical value in engineering practice.

Claims

1. A structure for realizing phase-locked loop of multi-magnetic-tron array based on a cascaded power distribution system, characterized in that, include: Cascaded power divider injection module, multiple mutually coupled magnetron phase-locked loop module; The cascaded power divider injection module includes at least one stage power divider injection module; The power divider injection module includes a solid-state microwave source, a first circulator, a seed magnetron, and a power divider. The solid-state microwave source is used to generate a stable microwave signal with an adjustable wide bandwidth, and injects it into the seed magnetron through a first circulator to lock the frequency of the seed magnetron. The first circulator is used to transmit the microwave signal reflected by the seed magnetron to the absorption load; The seed magnetron is used to generate a frequency-locked high-power microwave signal and transmit it to the power divider. The power divider is used to divide a high-power microwave signal into several microwave injection signals. When the cascaded power divider injection module contains only a single-stage power divider injection module, each microwave injection signal is input to a mutual-coupled magnetron phase-locked module to lock the signal frequency in the mutual-coupled magnetron phase-locked module. When the cascaded power divider injection module includes at least two power divider injection modules, the preceding power divider injection module serves as the microwave source for the following power divider injection module, providing a stable microwave signal to the seed magnetron in the following power divider injection module.

2. The structure for realizing phase-locked loop of multi-magnetic-tron array based on cascaded power distribution system as described in claim 1, characterized in that, The first-stage power divider injection module also includes a second circulator; the second circulator is disposed between the seed magnetron and the power divider, and is used to transmit the microwave signal reflected from the subsequent output link to the absorption load to stabilize the working state of the seed magnetron.

3. The structure for realizing phase-locked loop of multi-magnetic-tron array based on cascaded power distribution system as described in claim 2, characterized in that, A waveguide-to-coaxial converter is also provided between the solid-state microwave source and the circulator to realize the conversion of electromagnetic waves between two different transmission media.

4. The structure for realizing phase-locked loop of multi-magnetic-tron array based on cascaded power distribution system as described in claim 3, characterized in that, The mutual-coupled magnetron phase-locked module includes M magnetrons and M frequency-locked phase-locked units; the microwave injection signal is injected and locked to one magnetron through the frequency-locked phase-locked unit. When M≥2, all magnetrons establish mutual coupling paths through the frequency-locked phase-locked units to achieve frequency-locked phase-locking of the M magnetrons.

5. A structure for realizing phase-locked loop of multi-magnetic-tron array based on a cascaded power distribution system as described in claim 3 or 4, characterized in that, The stable microwave signal generated by the solid-state microwave source has a frequency band of 250 kHz-3000 MHz.

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