An X-band high-power wideband velocity-modulation tube amplifier

Abstract

The application discloses an X-band high-power wideband velocity modulation tube amplifier, comprising: an electron beam emitting module for generating a circular high-impedance high-current relativistic electron beam; a wideband injection module for externally injecting a microwave signal, absorbing the microwave signal, and preliminarily velocity modulating the high-current relativistic electron beam generated by the electron beam emitting module to convert the high-current relativistic electron beam into a gap electric field modulation electron beam; a high-frequency interaction module for further modulating the gap electric field modulation electron beam converted by the wideband injection module and generating bunching to increase the fundamental wave current modulation depth of each frequency of the high-current relativistic electron beam; and a wideband extraction module for converting the kinetic energy of the electron beam after the bunching of the high-frequency interaction module into microwave energy and coupling the microwave energy to an external circuit. The velocity modulation tube amplifier can realize high-power microwave output of corresponding frequencies and improve the working bandwidth of the velocity modulation tube amplifier in the X-band.

Description

Technical Field

[0001] The present invention relates to the technical field of high-power microwave source devices, and in particular to an X-band high-power broadband klystron amplifier. Background Art

[0002] The relativistic klystron amplifier (RKA) is a high-power microwave generator based on the principle of velocity modulation. It efficiently converts electron beam energy into microwave energy, offering numerous advantages such as high power, high efficiency, and controllable frequency and phase. In the high-power domain, it can be used in applications such as particle accelerators and high-power microwave communications. Furthermore, through spatially coherent power combination across multiple devices, the RKA can significantly improve far-field power density, offering significant application value in further increasing microwave power. The klystron amplifier utilizes a resonant cavity as an interaction circuit, which limits its instantaneous operating bandwidth. However, through techniques such as staggered tuning, the instantaneous operating bandwidth can be significantly expanded, leading to its widespread application in broadband scenarios such as radar systems and satellite communications.

[0003] However, the instantaneous power of conventional broadband klystron amplifiers is typically low, generally below 10 MW, especially in the X-band, where it is generally below 1 MW. Although researchers have simulated a 1 GW broadband klystron amplifier in the S-band and achieved a 12% 3dB relative bandwidth microwave output, the operating frequency band is relatively low, making it difficult to achieve high power and a wide relative bandwidth. This is partly because conventional broadband klystron amplifiers typically use continuous wave transmission and are used in applications that don't require high power, such as radar and communications. Furthermore, there are technical challenges. For example, the impedance of commonly used hot cathode diodes is too high, making further increases in transmission power difficult to achieve with very high voltages. Using a high compression ratio transmission method can also easily lead to poor electron beam quality. Furthermore, the breakdown voltage of each gap also limits the power handling capacity of the klystron amplifier. When the electron beam power rises to 100 MW, the electron beam already exhibits significant relativistic effects and is significantly affected by space charge effects.

[0004] There has been considerable research on increasing the power of klystron amplifiers, but these amplifiers are limited by their narrow operating bandwidth. In the X-band, their bandwidth typically does not exceed 50 MHz, essentially operating at a point frequency. To achieve high-power microwave output, relativistic klystrons typically employ a standing wave resonant cavity structure, which offers a high quality factor and strong resonance characteristics, resulting in high gain. However, this also means they operate almost at a point frequency, making it difficult to excite the electric field and modulate the electron beam outside of the resonant frequency. Furthermore, their electron beam impedance is low, resulting in fast modulation speeds. The maximum modulation depth can be achieved using two or three resonant cavities, making staggered tuning difficult. Existing X-band klystron amplifiers suffer from the following specific drawbacks:

[0005] (1) Limited by the working mechanism of the device, RKA is difficult to achieve broadband output in the X-band. As the output efficiency and power continue to improve in the development of high-frequency bands, except for the use of TKA (three-axis relativistic klystron amplifier) ​​that can achieve an output power of more than GW in the X-band, the output power of hollow devices in the high-frequency band is generally on the order of 100MW. Moreover, the research focus of relativistic klystron amplifiers is basically on narrowband devices, mainly focusing on improving output power and efficiency, and lacks solutions that can expand bandwidth.

[0006] (2) There are differences in the implementation principles of traditional high-power broadband klystron amplifiers and RKA. Currently, broadband klystron amplifiers are mainly used in continuous waves, and their peak power is generally low, making it impossible to directly realize high-power broadband microwave devices.

[0007] (3) Due to the limitations of geometric size and modulation depth, the number of resonant cavities of X-band RKA is limited, resulting in low output power, gain and even efficiency. Summary of the Invention

[0008] The technical problem to be solved by the present invention is: In view of the above problems in the prior art, an X-band high-power broadband klystron amplifier with multi-gap extraction is provided to broaden the operating bandwidth of the X-band RKA device and achieve higher gain and efficiency.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0010] An X-band high-power broadband klystron amplifier, comprising:

[0011] Electron beam emission module, used to generate hollow ring-shaped, high-impedance, high-current relativistic electron beam;

[0012] a broadband injection module, used for absorbing externally injected microwave signals and performing preliminary velocity modulation on the high-current relativistic electron beam generated by the electron beam emission module to convert it into a gap electric field modulated electron beam;

[0013] A high-frequency interaction module is used to further modulate the gap electric field modulated electron beam converted by the broadband injection module and generate clustering to increase the fundamental current modulation depth of each frequency of the high-current relativistic electron beam;

[0014] A broadband extraction module, used to convert the electron kinetic energy clustered by the high-frequency interaction module into microwave energy and couple it to an external circuit;

[0015] The electron beam emission module, broadband injection module, high-frequency interaction module and broadband extraction module are connected in sequence. When microwave signals of different frequencies are injected externally and fed into the broadband injection module, different working modes are excited at the gap of the broadband injection module. The high-current relativistic electron beam passing through is preliminarily velocity modulated by the axial electric field. The high-frequency interaction module further velocity modulates the high-current relativistic electron beam and generates clustering, thereby increasing the fundamental current modulation depth of each frequency of the high-current relativistic electron beam, forming a clustered electron beam in front of the output cavity, and establishing a strong high-frequency electric field.

[0016] As a further improvement of the above technical solution:

[0017] The electron beam emission module includes a cathode seat, a cathode, an anode and a tube wall. The cathode is arranged on the cathode seat. The anode and the tube wall are rotationally symmetrical about the central axis. A drift tube with a cavity structure is formed between the tube wall and the central axis. The cathode is opposite to the inlet side of the drift tube. The broadband injection module, the high-frequency interaction module and the broadband extraction module are arranged in sequence on the drift tube between the central axis and the tube wall along the direction of electron beam travel.

[0018] The broadband injection module and the high-frequency interaction module are arranged along the length direction of the drift tube. The modulation frequency of the broadband injection module and the high-frequency interaction module for the high-current relativistic electron beam is consistent with the frequency of the externally injected microwave.

[0019] The broadband injection module includes a microwave injection waveguide and a first resonant cavity arranged in sequence. The first resonant cavity includes a plurality of annular grooves provided on the tube wall and a gap opened between the central axis and the tube wall. The microwave injection waveguide is provided on the tube wall and communicates with the annular grooves.

[0020] The high-frequency interaction module includes a plurality of annular grooves arranged on the pipe wall and a gap opened between the central axis and the pipe wall. The top of each annular groove is respectively provided with attenuation materials of different thicknesses.

[0021] Each of the annular grooves of the high-frequency interaction module includes an annular drift tube coupling section and an annular re-entrant section that are interconnected; the top wall of the annular groove and the inner wall of the tube wall define the re-entrant section, and the gap between the central axis and the tube wall defines the drift tube coupling section corresponding to the position of the annular groove.

[0022] The broadband extraction module includes a second resonant cavity and a microwave output waveguide arranged in sequence; the second resonant cavity includes a plurality of annular grooves provided on the tube wall, and a gap opened between the central axis and the tube wall; the microwave output waveguide is a circular ring cavity provided between the tube walls.

[0023] The microwave output waveguide includes an inner section, a transition section and an outer section, the inner section is connected to the last annular groove of the second resonant cavity, the outer section is connected to an external circuit, and the transition section is connected to the inner section and the outer section.

[0024] The transition section of the microwave output waveguide is in a frustum shape, and the inner radius and outer radius of the frustum correspond to the outer radius of the last annular groove of the second resonant cavity and the outer radius of the outer section of the microwave output waveguide respectively.

[0025] The broadband extraction module further includes a metal tuning block, which is disposed on the anode and located at an outer section of the microwave output waveguide, and is used to adjust the quality factor of the broadband extraction module.

[0026] Compared with the prior art, the advantages of the present invention are:

[0027] The X-band high-power broadband klystron amplifier of the present invention generates a high-current relativistic electron beam with a hollow ring structure and high-impedance characteristics through an electron beam emission module. The hollow structure operates in a single mode, which can reduce structural complexity while avoiding mode competition, thereby improving the stability of the output microwave. The broadband injection module performs preliminary velocity modulation on the passing high-current relativistic electron beam to convert it into a gap electric field modulated electron beam. The high-frequency interaction module further deepens the velocity modulation of the high-current relativistic electron beam and generates clustering, thereby achieving absorption of the injected microwave power and modulation of the high-current relativistic electron beam within a wide frequency range. Finally, the broadband extraction module converts the electron kinetic energy of the highly clustered electron beam formed in front of the output cavity into microwave energy, and couples the output to an external circuit, thereby achieving broadband output in the X-band and improving the power of the klystron amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the structure of the X-band high-power broadband klystron amplifier of this embodiment.

[0029] Figure 2 Schematic diagram of the structure of the electron beam emission module and the broadband injection module of the X-band high-power broadband klystron amplifier of this embodiment.

[0030] Figure 3 Schematic diagram of the structure of the high-frequency interaction module of the X-band high-power broadband klystron amplifier of this embodiment.

[0031] Figure 4 Schematic diagram of the structure of the broadband extraction module of the X-band high-power broadband klystron amplifier of this embodiment.

[0032] Figure 5 1 is a typical microwave output waveform and electric field spectrum waveform diagram of the X-band high-power broadband klystron amplifier of this embodiment.

[0033] Figure 6 1 is an output microwave power-frequency curve of the X-band high-power broadband klystron amplifier of this embodiment.

[0034] Legend:

[0035] 1. Cathode seat; 2. Cathode; 3. Anode; 4. Tube wall; 5. Broadband injection module; 6. High-frequency interaction module; 7. Second resonant cavity; 8. Metal tuning block; 9. Microwave output waveguide. DETAILED DESCRIPTION

[0036] like Figure 1 As shown, this embodiment provides an X-band high-power broadband klystron amplifier, including:

[0037] Electron beam emission module ( Figure 1 As shown in the corresponding part A in FIG), it is used to generate a ring-shaped hollow, high-impedance high-current relativistic electron beam;

[0038] Broadband injection module 5 ( Figure 1 As shown in the corresponding part B in the figure), it is used for absorbing the externally injected microwave signal and performing preliminary velocity modulation on the high-current relativistic electron beam generated by the electron beam emission module to convert it into a gap electric field modulated electron beam;

[0039] High Frequency Interaction Module 6 ( Figure 1 As shown in the corresponding part C in the figure), it is used to further modulate the gap electric field modulated electron beam converted by the electron beam modulation module of the broadband injection module 5 and generate clustering to increase the fundamental current modulation depth of each frequency of the high-current relativistic electron beam;

[0040] Broadband extraction module ( Figure 1 (as shown in the corresponding part D in the figure) is used to convert the kinetic energy of the electrons clustered by the high-frequency interaction modules into microwave energy and couple it to the external circuit;

[0041] The electron beam emission module, the broadband injection module 5, the high-frequency interaction module 6 and the broadband extraction module are connected in sequence (the output end of the electron beam emission module is connected to the input end of the broadband injection module, the output end of the broadband injection module is connected to the input end of the high-frequency interaction module, and the output end of the high-frequency interaction module is connected to the input end of the broadband extraction module). When microwave signals of different frequencies are injected externally and fed into the broadband injection module 5, different working modes are excited at the gap of the broadband injection module 5, and the high-current relativistic electron beam passing through is preliminarily velocity modulated by the axial electric field. The high-frequency interaction module 6 further velocity modulates the high-current relativistic electron beam and generates clustering, thereby increasing the fundamental current modulation depth of each frequency of the high-current relativistic electron beam, forming a clustered electron beam in front of the output cavity, and establishing a strong high-frequency electric field.

[0042] It can be understood that the electron beam emission module generates a high-current relativistic electron beam with an annular hollow structure and high impedance characteristics, which can improve the stability and uniformity of the beam, work in a single mode, and do not produce mode competition compared to the over-mode structure, providing a basis for subsequent modulation and energy conversion; the broadband injection module performs preliminary velocity modulation on the passing high-current relativistic electron beam by externally injecting microwave signals, converting it into a gap electric field modulated electron beam, which can make the electron beam fundamental current modulation depth not less than a specified value, for example, not less than 4%; the high-frequency interaction module further deepens the velocity modulation of the high-current relativistic electron beam and produces clustering. For example, the further deepening of the high-frequency interaction module can make the current fundamental modulation depth of each frequency not less than 110%; the broadband extraction module converts the electron kinetic energy of the highly clustered electron beam formed in front of the output cavity into microwave energy, and couples the output to the external circuit to achieve signal amplification.

[0043] In this embodiment, Figure 2 As shown, the electron beam emission module includes a cathode seat 1, a cathode 2, an anode 3 and a tube wall 4. The cathode 2 is arranged on the cathode seat 1, the anode 3 and the tube wall 4 are rotationally symmetrical about the central axis OZ, and a drift tube with a cylindrical cavity structure is formed between the tube wall 4 and the central axis OZ. The cathode 2 is facing the inlet side of the drift tube, and the broadband injection module, the high-frequency interaction module 6 and the broadband extraction module are arranged in sequence on the drift tube between the central axis OZ and the tube wall 4 along the direction of electron beam travel.

[0044] Specifically, if Figure 2 As shown, a drift tube with a hollow structure of radius R1 is formed between the central axis OZ and the tube wall 4, wherein the drift tube located between the electron beam emission module and the broadband injection module is the first drift section, the drift tube located between the broadband injection module and the high-frequency interaction module is the second drift section, and the drift tube located between the high-frequency interaction module and the broadband extraction module is the third drift section, and the radius of the three drift sections is R1. The size parameters of the cathode seat 1, cathode 2 and tube wall 3 can be obtained by optimizing the operating voltage and current of the device. The anode 3 and tube wall 4 can be selected according to the required conductor material, such as aluminum, stainless steel, oxygen-free copper, etc. Preferably, a diode based on a high-impedance explosive emission cold cathode is adopted, and a high-power and high-impedance electron beam is used. Compared with hot cathode emission, it has higher power and electron beam quality, which can solve the problems of low impedance and short drift distance of traditional cold cathode explosive emission diodes. In addition, the inner side of the tube wall 4 is a vacuum, and the entire X-band high-power broadband klystron amplifier is a hollow structure with no internal conductor. The hollow structure operates in a single mode, which can reduce structural complexity while avoiding mode competition and improving the stability of the output microwave.

[0045] In this embodiment, the broadband injection module 5 and the high-frequency interaction module 6 are arranged along the length of the drift tube. The modulation frequency of the broadband injection module 5 and the high-frequency interaction module 6 for the high-current relativistic electron beam is consistent with the frequency of the externally injected microwave. It can be understood that when the modulation frequency is consistent with the injected microwave frequency, the external microwave signal can effectively interact with the electron beam, maximizing the transfer of microwave energy to the electron beam, achieving a more efficient modulation process, and improving the modulation depth and overall system efficiency.

[0046] In this embodiment, Figure 2 As shown, the broadband injection module 5 includes a microwave injection waveguide and a first resonant cavity arranged in sequence. The first resonant cavity includes a plurality of annular grooves provided on the tube wall 4 and a gap opened between the central axis OZ and the tube wall 4. The microwave injection waveguide is provided on the tube wall 4 and is connected to the annular grooves.

[0047] In a specific application embodiment, Figure 2 As shown, the broadband injection module comprises a microwave injection waveguide and a first resonant cavity (also known as a broadband injection cavity) arranged adjacent to each other. The first resonant cavity comprises three annular grooves in the tube wall 4 and a gap between the tube walls along the central axis OZ. The radius of the gap between the grooves is R2, slightly larger than the radius R1 of the drift tube. A microwave injection waveguide is provided on the tube wall 4, connected to the annular grooves. The three annular grooves form a three-gap disk-like structure of the first resonant cavity. Each of the three annular grooves has a length of L5 and radii of R4, R5, and R5, respectively. The radius of the gap between the grooves is R2, and the width of the two gaps between the three annular grooves is L6. The inner and outer radii of the energy feed ring of the first resonant cavity are R3 and R4, respectively. The lower side of the energy feed ring of the first resonant cavity is connected to the injection cavity. The electron beam interacts with the injected microwave signal, converting the injected seed microwave signal into velocity modulation of the electron beam.

[0048] It can be understood that the broadband injection module 5 has a multi-gap structure. Since there are gaps between the annular grooves, the multi-gap resonant cavity can operate in different longitudinal modes. There is a frequency interval between the longitudinal modes, so the frequency sensitivity is weak, which can reduce the frequency sensitivity within the working frequency band, obtain a wider bandwidth, and realize the absorption of injected microwave power and the modulation of high-current relativistic electron beams within a wider frequency range.

[0049] In this embodiment, Figure 3 As shown, the high-frequency interaction module 6 includes a plurality of annular grooves provided on the tube wall 4 and a gap between the central axis OZ and the tube wall 4 . The top of each annular groove is provided with attenuation materials of different thicknesses.

[0050] In this embodiment, each annular groove of the high-frequency interaction module 6 includes an annular drift tube coupling section and an annular re-entrant section that are interconnected; the top wall of the annular groove and the inner wall of the tube wall 4 define the re-entrant section, and the gap between the central axis OZ and the tube wall 4 corresponds to the position of the annular groove to define the drift tube coupling section.

[0051] In a specific application embodiment, Figure 3 As shown, the high-frequency interaction module 6 includes eight annular grooves in the tube wall 4 and a gap between the central axis OZ and the tube wall 4. The tops of the annular grooves in the tube wall 4 are loaded with attenuation material of varying thicknesses, with the thicknesses of the loaded attenuation material ranging from h1 to h8. The annular grooves are re-entrant structures, and the eight annular grooves constitute the eight-gap disk-loaded structure of the high-frequency interaction module 6. The re-entrant structure is composed of an annular drift tube coupling section and an annular re-entrant section. The eight annular drift tube coupling sections all have an inner radius of R1, an outer radius of R6, and lengths ranging from d1 to d8. The eight annular re-entrant sections all have an inner radius of R6, an outer radius ranging from R7 to R14, and lengths ranging from L7 to L14. The spacing between each annular re-entrant section ranges from w1 to w7.

[0052] It can be understood that the high-frequency interaction module 6 has an 8-level structure, and the resonant cavities of different levels have different resonant frequencies, so it can effectively modulate signals of various frequencies within the frequency band; the gaps of the high-frequency interaction module are re-entrant structures, and the gaps are independent of each other, and there is no coupling; in addition, according to the RKA resonant cavity theory, the 3dB relative bandwidth width of the resonant cavity is inversely proportional to the quality factor Q value. The top of the resonant cavity (i.e., the annular groove) of the high-frequency interaction module is loaded with attenuation material, so that the quality factor of the resonant cavity is only one tenth or even one hundredth of that of the general resonant cavity. By adjusting the resonant frequency and quality factor Q of the resonant cavity, staggered tuning is achieved, so that the high-frequency interaction module has a larger bandwidth.

[0053] In this embodiment, Figure 4 As shown, the broadband extraction module includes a second resonant cavity 7 and a microwave output waveguide 9 arranged in sequence; the second resonant cavity 7 includes a plurality of annular grooves provided on the tube wall 4, and a gap opened between the central axis OZ and the tube wall 4; the microwave output waveguide 9 is a circular ring cavity provided between the tube walls 4.

[0054] In this embodiment, the microwave output waveguide 9 includes an inner section, a transition section and an outer section. The inner section is connected to the last annular groove of the second resonant cavity 7, the outer section is connected to the external circuit, and the transition section connects the inner section and the outer section.

[0055] In this embodiment, the transition section of the microwave output waveguide 9 is in the shape of a truncated cone, and the inner radius and outer radius of the truncated cone correspond to the outer radius of the last annular groove of the second resonant cavity 7 and the outer radius of the outer section of the microwave output waveguide 9 respectively.

[0056] In this embodiment, the broadband extraction module further includes a metal tuning block 8 , which is provided on the anode 3 and located at the outer section of the microwave output waveguide 9 , and is used to adjust the quality factor of the broadband extraction module.

[0057] In a specific application embodiment, Figure 4 As shown, the broadband extraction module comprises a three-gap resonant cavity 7, a collector, and a microwave output waveguide 9, arranged adjacent to each other. The three-gap resonant cavity comprises three annular grooves in the tube wall 4 and a gap defined between the central axis OZ and the tube wall 4. The microwave output waveguide 9 is a circular, ring-shaped cavity located within the tube wall 4, containing a metal tuning block 8. The three annular grooves in the three-gap resonant cavity each have a length of L15, with radii of R15, R16, and R17, respectively. The radius between the three annular grooves is R2, and the width of the two gaps between the three annular grooves is L16. In practical applications, the parameters of the three-gap resonant cavity 7 can be optimized based on actual application requirements. The inner and outer radii of the portion where the microwave output waveguide 9 of the broadband extraction module connects to the last annular groove (i.e., the inner section) are R18 and R17, respectively. The inner and outer radii of the annular waveguide connecting the microwave output waveguide 9 to the external circuit (i.e., the outer section) are R18 and R19, respectively. The inner and outer radii of the frustum (i.e., the transition section) used to connect the two sections of the annular waveguide are R17 and R19, respectively. An annular metal tuning block 8 located on the inner conductor (i.e., the anode 3) is provided in the cavity of the last section of the annular waveguide (i.e., the outer section). The metal tuning block 8 has a length of L16 and a height of h9 about the central axis OZ as its rotational symmetry axis and is used to adjust the quality factor of the broadband output module.

[0058] It can be understood that, similar to the broadband injection module 5, the three-gap resonant cavity 7 of the broadband extraction module is a disk-load structure, which is used to achieve high-efficiency conversion of beam-wave energy. The multi-gap structure can also improve the power capacity of the device; the three-gap structure allows it to operate in different longitudinal modes, and there is a frequency interval between the longitudinal modes, so the frequency sensitivity within the operating frequency band can be reduced, and a wider bandwidth can be obtained. The broadband injection module and the broadband extraction module adopt a cross-mode multi-gap injection and output structure that works in a single mode. While obtaining a larger bandwidth, compared to the coupled structure, the mode is pure, no stray modes are generated, and it has good frequency locking characteristics. In addition, since the modulation frequency of the high-current relativistic electron beam is consistent with the frequency of the externally injected microwave, the frequency of the output high-power microwave HPM is also consistent with the frequency of the externally injected microwave.

[0059] In a specific application embodiment, the relevant parameters of the X-band high-power broadband klystron amplifier structure are as follows: 0.18λ < R1 < 0.3λ, 0.25λ < R2 < 0.3λ, 4.4λ < R3 < 4.5λ, 1mm < R4 - R3 < 2mm, R5 < 4.5λ, 0.34λ < R6~R14 < 0.37λ, 2λ < L2 < 3λ, 0.9λ < L3 < 1.2λ, L5 < 0.25λ < L6~L15 < 0.3λ, 1 mm < L16 < 4mm, 4mm < L17 < 6mm, h1~h8 < 2mm, h9 < 4mm, 0.16λ < d1~d8 < 0.18λ, 4λ < w1~w7 < 5λ, L1 and L4 can be optimized according to requirements, and the radial size of the klystron amplifier is less than that of the traditional high-power klystron.

[0060] As Figure 5 shown in the figure are the typical output power waveform and the electric field spectrum waveform diagram of the X-band high-power broadband klystron amplifier in this embodiment. Under the conditions of an emitted electron beam voltage of 550 kV, a current of 550 A, and an injection power of 10 kW (both the pulsed power source and the antenna are common structures in the high-power microwave HPM field), this amplifier can achieve a maximum power of 140 MW and an efficiency of 46%. At the same time, Figure 6 is the output microwave power-frequency curve of the X-band high-power broadband klystron amplifier. It can be seen that the center frequency point is approximately 9.8 GHz. Within the 3 dB operating bandwidth of 6.5% (i.e., 650 MHz), the instantaneous power output is not less than 90 MW. It can be seen that by changing the frequency of the microwave injection signal, high-power microwave output corresponding to the frequency can be achieved, solving the problem that the bandwidth of existing relativistic klystrons is generally low.

[0061] The working principle of the high-power broadband klystron amplifier in this embodiment is as follows: When different microwave signals are externally injected and fed into the broadband injection module 5, electric fields of different coaxial operating modes will be excited at the gap of the first resonant cavity, and their axial electric fields will perform a preliminary velocity modulation on the passing intense relativistic electron beam; the velocity modulation of the intense relativistic electron beam is deepened by the high-frequency interaction module 6 to achieve an electron beam modulation depth of not less than 120%; finally, a highly bunched electron beam is formed in front of the output cavity, establishing a strong high-frequency electric field. When the electrons pass through the gap, their velocity decreases, and kinetic energy is converted into microwave energy, realizing signal amplification.

[0062] The above is only the preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. An X-band high-power broadband klystron amplifier, characterized in that: include: Electron beam emission module, used to generate annular hollow, high-impedance high-current relativistic electron beam; A broadband injection module (5) is used for absorbing externally injected microwave signals and performing preliminary velocity modulation on the high-current relativistic electron beam generated by the electron beam emission module to convert it into a gap electric field modulated electron beam; A high-frequency interaction module (6) is used to further modulate the gap electric field modulated electron beam converted by the broadband injection module (5) and generate clustering, so as to increase the fundamental current modulation depth of each frequency of the high-current relativistic electron beam; A broadband extraction module, used to convert the electron kinetic energy clustered by the high-frequency interaction module into microwave energy and couple it to an external circuit; The electron beam emission module, the broadband injection module (5), the high-frequency interaction module (6), and the broadband extraction module are connected in sequence. When microwave signals of different frequencies are injected externally and fed into the broadband injection module (5), electric fields of different working modes are excited at the gap of the broadband injection module (5). The high-current relativistic electron beam passing through is subjected to preliminary velocity modulation by the axial electric field. The high-frequency interaction module (6) further performs velocity modulation on the high-current relativistic electron beam and generates clustering, thereby increasing the fundamental current modulation depth of each frequency of the high-current relativistic electron beam, forming a clustered electron beam in front of the output cavity, and establishing a strong high-frequency electric field. The electron beam emission module comprises a cathode seat (1), a cathode (2), an anode (3) and a tube wall (4); the cathode (2) is arranged on the cathode seat (1); the anode (3) and the tube wall (4) are rotationally symmetrical about a central axis; a drift tube with a cavity structure is formed between the tube wall (4) and the central axis; the cathode (2) faces the inlet side of the drift tube; the broadband injection module, the high-frequency interaction module (6) and the broadband extraction module are sequentially arranged on the drift tube between the central axis and the tube wall (4) along the traveling direction of the electron beam; The broadband extraction module comprises a second resonant cavity (7) and a microwave output waveguide (9) arranged in sequence; the second resonant cavity (7) comprises a plurality of annular grooves provided on the tube wall (4), and a gap provided between the central axis and the tube wall (4); the microwave output waveguide (9) is a circular ring cavity provided between the tube walls (4); The microwave output waveguide (9) comprises an inner section, a transition section and an outer section, the inner section is connected to the last annular groove of the second resonant cavity (7), the outer section is connected to an external circuit, and the transition section is connected to the inner section and the outer section; The transition section of the microwave output waveguide (9) is in the shape of a truncated cone, and the inner radius and outer radius of the truncated cone correspond to the outer radius of the last annular groove of the second resonant cavity (7) and the outer radius of the outer section of the microwave output waveguide (9), respectively; The broadband extraction module further comprises a metal tuning block (8), which is arranged on the anode (3) and located at the outer section of the microwave output waveguide (9) and is used to adjust the quality factor of the broadband extraction module.

2. The X-band high-power broadband klystron amplifier according to claim 1, characterized in that: The broadband injection module (5) and the high-frequency interaction module (6) are arranged along the length direction of the drift tube, and the modulation frequency of the broadband injection module (5) and the high-frequency interaction module (6) for the high-current relativistic electron beam is consistent with the frequency of the externally injected microwave.

3. The X-band high-power broadband klystron amplifier according to claim 2, characterized in that: The broadband injection module (5) comprises a microwave injection waveguide and a first resonant cavity arranged in sequence, the first resonant cavity comprising a plurality of annular grooves provided on a tube wall (4) and a gap opened between the central axis and the tube wall (4), the microwave injection waveguide being provided on the tube wall (4) and communicating with the annular grooves.

4. The X-band high-power broadband klystron amplifier according to claim 1, wherein: The high-frequency interaction module (6) comprises a plurality of annular grooves provided on the tube wall (4) and a gap opened between the central axis and the tube wall (4), and the top of each annular groove is provided with attenuation materials of different thicknesses.

5. The X-band high-power broadband klystron amplifier according to claim 4, characterized in that: Each of the annular grooves of the high-frequency interaction module (6) includes an annular drift tube coupling section and an annular re-entrant section that are interconnected; the top wall of the annular groove and the inner wall of the tube wall (4) define the re-entrant section, and the gap between the central axis and the tube wall (4) corresponds to the position of the annular groove to define the drift tube coupling section.

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