Multi-mode overlapping interaction circuit to broaden the bandwidth of terahertz extended interaction klystron

Abstract

A multi-mode overlapping interaction circuit for widening the bandwidth of a terahertz extended interaction klystron comprises: an input cavity unit, an intermediate cavity unit and an output cavity unit. The input cavity unit is excited by a terahertz wave signal from the outside to generate a multi-mode overlapping resonance field, and the multi-mode overlapping resonance field generated by the input cavity unit interacts with an electron beam from the outside, thereby modulating the electron beam from the outside; the intermediate cavity unit generates a multi-mode overlapping resonance field under the excitation of the electron beam output by the input cavity unit, and the multi-mode overlapping resonance field generated by the intermediate cavity unit modulates the electron beam output by the input cavity unit; the output cavity unit generates a multi-mode overlapping resonance field under the excitation of the electron beam output by the intermediate cavity unit, and interacts with the electron beam output by the intermediate cavity unit to further obtain energy, so that the terahertz high-frequency field with the same frequency as the input signal is further enhanced, and a terahertz wave signal with increased power is output.

Description

Technical Field

[0001] The invention relates to the technical field of multi-mode overlapping interaction klystrons, and in particular to a multi-mode overlapping interaction circuit for broadening the bandwidth of a terahertz extended interaction klystron. Background Art

[0002] The multi-mode overlapping interaction klystron (EIK) is a miniaturized, compact high-power radiation source with the advantages of high power, high efficiency, high stability and long life. It has important applications in high-power millimeter-wave radar, long-distance high-speed wireless communication, millimeter-wave electronic countermeasures, national security, controlled nuclear fusion and industrial applications. The high-frequency structure of the terahertz multi-mode overlapping interaction klystron is generally composed of multiple multi-gap resonant cavities. The electron beam and the beam wave in the resonant cavity interact and exchange energy to output a radio frequency signal. Therefore, the bandwidth of the resonant mode of the multi-gap resonant cavity determines the bandwidth of the terahertz multi-mode overlapping interaction klystron.

[0003] Staggered tuning is a general method to broaden the bandwidth of multi-mode overlapping interaction klystrons. This method adjusts the resonant frequency of the device's middle cavity so that its resonant frequency is distributed above and below the center frequency, thereby broadening the bandwidth of the device. Another method to broaden the bandwidth of a multi-mode overlapping interaction klystron is to coat the cavity with attenuation material to reduce the cavity's quality factor and increase the resonant mode bandwidth. However, as multi-mode overlapping interaction klystrons develop toward the terahertz frequency band, the size of the device is getting smaller and smaller, and even slight processing errors can cause the resonant frequency of the cavity to change, affecting the staggered tuning of the device and even rendering the staggered tuning ineffective. Similarly, too small a cavity size can make the coating of attenuation material extremely difficult. Summary of the invention

[0004] In view of this, the present invention proposes a multi-mode overlapping interaction circuit for broadening the bandwidth of a terahertz extended interaction klystron to solve one of the above problems.

[0005] As a first aspect of the present invention, a multi-mode overlapping interaction circuit for broadening the bandwidth of a terahertz extended interaction klystron is provided, comprising: an input cavity unit, an intermediate cavity unit and an output cavity unit connected in sequence;

[0006] An input cavity unit, wherein the input cavity unit is excited by a terahertz wave signal from the outside to generate a multi-mode overlapping resonance field; the multi-mode overlapping resonance field generated by the input cavity unit is suitable for interacting with an electron beam from the outside to modulate the electron beam from the outside;

[0007] The intermediate cavity unit is adapted to generate a multi-mode overlapping resonance field under the excitation of the electron beam output by the input cavity unit, and the multi-mode overlapping resonance field generated by the intermediate cavity unit is adapted to interact with the electron beam output by the input cavity unit to modulate the electron beam output by the input cavity unit;

[0008] An output cavity unit, adapted to generate a multi-mode overlapping resonance field under the excitation of the electron beam output by the intermediate cavity unit, wherein the multi-mode overlapping resonance field generated by the output cavity unit is adapted to interact with the electron beam output by the intermediate cavity unit so that the multi-mode overlapping resonance field generated by the output cavity absorbs energy from the electron beam output by the intermediate cavity unit, and outputs a terahertz wave signal with increased power;

[0009] The input cavity unit, the intermediate cavity unit and the output cavity unit have the same multimode mode, the multimode mode includes multiple resonance modes, the absolute value of the difference between the resonance frequency corresponding to each of the multiple resonance modes and the operating frequency of the terahertz multimode overlapping interaction klystron and the operating frequency of the terahertz multimode overlapping interaction klystron are all less than or equal to 1%; the difference between the maximum value and the minimum value of the phase shift angle corresponding to each of the multiple resonance modes is less than or equal to The velocity of the electron beam is between the maximum value and the minimum value of the phase velocity of the forward wave components corresponding to each of the plurality of resonance modes.

[0010] According to an embodiment of the present invention, the input cavity unit includes an input cavity, and the input cavity includes a trapezoidal structure; the intermediate cavity unit includes 4 intermediate cavities, and each intermediate cavity includes the trapezoidal structure; the output cavity unit includes an output cavity, and the output cavity includes the trapezoidal structure; the trapezoidal structure includes 14 trapezoidal structure units arranged in sequence along the axial direction, and the 14 trapezoidal structure units form a periodic arrangement structure; the input cavity, the intermediate cavity and the output cavity have the multi-mode mode;

[0011] Each of the trapezoidal structural units includes a trapezoidal structural unit body, on which a first coupling cavity, a second coupling cavity and an electron injection channel located between the first coupling cavity and the second coupling cavity are sequentially formed, and the first coupling cavity, the second coupling cavity and the electron injection channel are connected by a gap.

[0012] According to an embodiment of the present invention, the height of the first coupling cavity is 0.18 mm and the width is 0.4 mm, the height of the second coupling cavity is 0.18 mm and the width is 0.4 mm, the width of the gap is 0.6 mm and the height is 0.4 mm, the radius of the electron injection channel is 0.11 mm, and the period length of the periodic arrangement structure is 0.22 mm.

[0013] According to an embodiment of the present invention, the input cavity unit further includes a first drift tube, which is arranged between the input cavity and the intermediate cavity; the intermediate cavity unit further includes a plurality of second drift tubes, which are arranged between two adjacent intermediate cavities and between the intermediate cavity and the output cavity.

[0014] According to an embodiment of the present invention, the input cavity unit is further provided with an electron beam injection port, which is suitable for injecting electron beams from the outside into the input cavity;

[0015] The output cavity unit is also provided with an electron beam output port, which is suitable for transmitting the electron beam whose energy is absorbed by the output cavity.

[0016] According to an embodiment of the present invention, the quality factors of all the resonance modes of the input cavity and the external quality factors of all the resonance modes of the output cavity are both less than 1000.

[0017] According to an embodiment of the present invention, the multi-mode overlapping interaction circuit further includes:

[0018] An input waveguide, suitable for inputting a terahertz wave signal from the outside;

[0019] The first coupling structure is used to connect the input waveguide and the input cavity unit. A first coupling hole is formed on the first coupling structure. The first coupling hole is used to input the terahertz wave signal from the input waveguide into the input cavity unit.

[0020] According to an embodiment of the present invention, the multi-mode overlapping interaction circuit further includes:

[0021] a second coupling structure connected to the output cavity, wherein a second coupling hole is formed on the second coupling structure, and the second coupling hole is suitable for transmitting the terahertz wave signal with increased power output by the output cavity;

[0022] The output waveguide is adapted to output the terahertz wave signal with increased power from the second coupling structure.

[0023] According to an embodiment of the present invention, by making the input cavity unit, the intermediate cavity unit and the output cavity have the same multi-mode mode, and satisfying that the absolute value of the difference between the resonant frequency corresponding to each of the multiple resonant modes in the multi-mode mode and the operating frequency of the terahertz multi-mode overlapping interaction klystron and the operating frequency of the terahertz multi-mode overlapping interaction klystron are all less than or equal to 1%, and the difference between the maximum value and the minimum value of the phase shift angle of each of the multiple resonant modes is less than or equal to The speed of the electron beam is between the maximum and minimum values ​​of the phase velocity of the forward wave component corresponding to each of the multiple resonant modes, so that the bandwidth of the multi-mode overlapping interaction circuit can be the sum of the bandwidths of each resonant mode, thereby improving the bandwidth relative to a multi-mode overlapping interaction circuit with only a single resonant mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A three-dimensional diagram schematically shows a multi-mode overlapping interaction circuit provided according to an embodiment of the present invention;

[0025] Figure 2 A three-dimensional diagram of a trapezoidal structure provided according to an embodiment of the present invention is schematically shown;

[0026] Figure 3 A schematic perspective view of a trapezoidal structural unit provided according to an embodiment of the present invention is shown;

[0027] Figure 4 A schematic cross-sectional view of a body-shaped structural unit along the A1-A2 direction provided according to an embodiment of the present invention is shown;

[0028] Figure 5 A dispersion curve diagram of a multi-mode overlapping interaction circuit provided according to an embodiment of the present invention is schematically shown;

[0029] Figure 6 A gain diagram of a terahertz wave signal at different frequencies in a multi-mode overlapping interaction circuit with multi-mode overlapping is schematically shown according to an embodiment of the present invention;

[0030] Figure 7 The diagram schematically shows the output power diagram corresponding to the terahertz wave signals at different frequencies when the input terahertz wave signal power is 150 mW.

[0031] Description of Reference Numerals

[0032] 1 Resonant Cavity Module

[0033] 11 Input cavity unit

[0034] 111 First Drift Tube

[0035] 112 electronic injection input port

[0036] 12 Middle cavity unit

[0037] 121 Second drift tube

[0038] 13 output cavity unit

[0039] 131 electronic injection output port

[0040] 14 Trapezoidal structure

[0041] 141 ladder structure unit

[0042] 141-1 ladder structure unit body

[0043] 141-2 First coupling cavity

[0044] 141-3 Second coupling cavity

[0045] 141-4 electron injection channel

[0046] 141-5 Gap

[0047] 2 Input waveguide

[0048] 3. First coupling structure

[0049] 4 Second coupling structure

[0050] 5 Output waveguide DETAILED DESCRIPTION

[0051] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0052] Figure 1 The figure schematically shows a front view of a multi-mode overlapping interaction circuit provided according to an embodiment of the present invention.

[0053] like Figure 1 As shown, the multi-mode overlapping interaction circuit includes: a resonant cavity module 1. The resonant cavity module 1 includes: an input cavity unit 11, an intermediate cavity unit 12 and an output cavity unit 13 which are coaxially arranged and connected in sequence. The input cavity unit 11 is excited by a terahertz wave signal from the outside to generate a multi-mode overlapping resonance field. The multi-mode overlapping resonance field generated by the input cavity unit 11 is suitable for interacting with an electron beam from the outside to modulate the electron beam from the outside. The intermediate cavity unit 12 is suitable for generating a multi-mode overlapping resonance field under the excitation of the electron beam output by the input cavity. The multi-mode overlapping resonance field generated by the intermediate cavity unit 12 is suitable for interacting with the electron beam output by the input cavity unit 11 to modulate the electron beam output by the input cavity unit 11. The output cavity unit 13 is suitable for generating a multi-mode overlapping resonance field under the excitation of the electron beam output by the intermediate cavity unit 12. The multi-mode overlapping resonance field generated by the output cavity unit 13 is suitable for interacting with the electron beam output by the intermediate cavity unit 11 so that the multi-mode overlapping resonance field generated by the output cavity absorbs energy from the electron beam output by the intermediate cavity unit, and outputs a terahertz wave signal with increased power.

[0054] The input cavity unit 11, the intermediate cavity unit 12 and the output cavity unit 13 have the same multi-mode mode. The multi-mode mode includes multiple resonant modes, and the absolute value of the difference between the resonant frequency corresponding to each of the multiple resonant modes and the operating frequency of the terahertz multi-mode overlapping interaction klystron and the operating frequency of the terahertz multi-mode overlapping interaction klystron are all less than or equal to 1%; the difference between the maximum value and the minimum value of the phase shift angle of each of the multiple resonant modes is less than or equal to The speed of the electron beam is between the maximum and minimum values ​​of the phase speeds of the forward wave components corresponding to the multiple resonance modes. The multi-mode overlapping interaction circuit that meets the above conditions is a multi-mode overlapping interaction circuit.

[0055] Taking multiple resonant modes as two resonant modes, the following conditions should be met:

[0056]

[0057]

[0058]

[0059] Among them, in formulas (1)-(2), f1 and f2 are the resonant frequencies of the two resonant modes respectively, and f is the operating frequency of the multi-mode overlapping interaction klystron. and are the phase shift angles corresponding to the two resonant modes. For equation (3), c is the speed of light, the electron is the injection voltage U0, the operating frequency is f, and the period length of the periodic arrangement structure is p. And both sides of the equation represent the electron beam velocity, is the phase shift angle of the working mode of the multi-mode overlapping interaction circuit, and are the velocities of the terahertz wave signals corresponding to the two resonance modes.

[0060] For EIK (multi-mode overlapping interaction klystron), the bandwidth of the resonant mode in the resonant cavity determines the bandwidth of the multi-mode overlapping interaction klystron. This is because, in the intermediate cavity unit, if the frequency information carried by the electron beam is not within the bandwidth of the resonant mode, the multi-mode overlapping resonant field excited by the electron beam will be very weak, and the modulation of the electron beam by the multi-mode overlapping resonant field will also be very weak. The combination of these two factors will make the intermediate cavity unit ineffective. In the input cavity unit, the input signal is not within the bandwidth of the resonant mode, a large amount of signal energy will be reflected, the multi-mode overlapping resonant field in the input cavity unit will be very weak, and the modulation of the electron beam will also be very weak. In the output cavity unit, if the frequency information carried by the electron beam is not within the bandwidth, the field excited by the electron beam will be very weak, so the energy of the output signal will be very low. Therefore, the bandwidth of the resonant modes of the input cavity unit, the intermediate cavity unit, and the output cavity unit jointly determine the bandwidth of EIK.

[0061] According to an embodiment of the present invention, a multi-mode overlapping interaction circuit is generally composed of a plurality of multi-mode overlapping interaction cavities. Among them, the resonant cavity (including the input cavity unit, the intermediate cavity unit and the output cavity unit) generally works in a single mode, and the bandwidth of the mode determines the working bandwidth of the device. Therefore, the cavity can be designed to work in two or more different resonant modes at the same time to broaden the bandwidth of the device.

[0062] According to the multi-mode overlapping interaction circuit provided by the embodiment of the present invention, the input cavity unit 11, the intermediate cavity unit 12 and the output cavity 13 have the same multiple resonance modes, and the difference between the resonance frequencies of the multiple resonance modes is less than or equal to 3%, that is, the multiple resonance modes of the input cavity unit 11, the intermediate cavity unit 12 and the output cavity 13 overlap with each other. At the same time, the difference between the synchronization voltage of the multiple resonance modes and the voltage of the electron beam is less than the preset threshold, that is, the multiple overlapping resonance modes (multi-mode overlapping resonance modes) of the input cavity unit 11, the intermediate cavity unit 12 and the output cavity 13 can interact with the electron beam. Therefore, the bandwidth of the multi-mode overlapping interaction circuit provided by the embodiment of the present invention is the sum of the bandwidths of the multiple resonance modes. Compared with the multi-mode overlapping interaction circuit in which the input cavity unit 11, the intermediate cavity unit 12 and the output cavity 13 have only one resonance mode, the multi-mode overlapping interaction circuit of the present application can expand the bandwidth.

[0063] According to an embodiment of the present invention, the input cavity unit 11 includes an input cavity, the intermediate cavity unit 12 includes four intermediate cavities, and the output cavity unit 13 includes an output cavity. The input cavity, the intermediate cavity, and the output cavity are all resonant cavities and have the same multi-mode mode; the multi-mode overlapping resonant fields generated by the input cavity, the intermediate cavity, and the output cavity in the multi-mode mode are all used to modulate the velocity of the electron beam. Figure 2As shown, the input cavity, the output cavity, and the intermediate cavity include the same trapezoidal structure 14, and the trapezoidal structure 14 includes a plurality of trapezoidal structural units 141, and the plurality of trapezoidal structural units form a periodic arrangement structure. Figure 3-Figure 4 As shown, each trapezoidal structural unit includes a trapezoidal structural unit body 141-1, on which are sequentially formed a first coupling cavity 141-2, a second coupling cavity 141-3, and an electron injection channel 141-4 located between the first coupling cavity and the second coupling cavity, which penetrate the trapezoidal structural unit body 141-1, and the first coupling cavity, the second coupling cavity, and the electron injection channel 141-4 are connected through a gap 141-5. The number of the electron injection channels 141-4 can be one or more, and the multiple electron injection channels can be evenly distributed on the coupling gap, and the shape can be cylindrical or other shapes, and the multiple electron injection channels can be evenly distributed on the coupling gap.

[0064] According to an embodiment of the present invention, the size of the first coupling cavity 141-2, the size of the second coupling cavity 141-3, the size of the gap 141-5, the period length of the periodic arrangement structure, and the number of the trapezoidal structure units 141 are configured so that the input cavity, the intermediate cavity, and the output cavity all have multiple resonant modes, and the absolute value of the difference between the resonant frequencies corresponding to the multiple resonant modes and the operating frequency of the terahertz multi-mode overlapping interaction klystron and the operating frequency of the terahertz multi-mode overlapping interaction klystron are less than or equal to 1%, and the difference between the maximum value and the minimum value of the phase shift angle corresponding to the multiple resonant modes is less than or equal to And the speed of the electron beam is between the maximum and minimum values ​​of the phase velocity of the forward wave component corresponding to each of the multiple resonance modes. For example, the number of intermediate cavities is 4, the height of the first coupling cavity is 0.18 mm and the width is 0.4 mm, the height of the second coupling cavity is 0.18 mm and the width is 0.4 mm, the width of the gap is 0.6 mm and the height is 0.4 mm, the radius of the electron beam channel is 0.11 mm, the period length is 0.22 mm, and the number of trapezoidal structural units is 14.

[0065] According to an embodiment of the present invention, the input cavity unit 11 further comprises a first drift tube 111 disposed between the input cavity and the intermediate cavity. The intermediate cavity unit further comprises a plurality of second drift tubes 121 disposed between two adjacent intermediate cavities and between the intermediate cavity and the output cavity, each drift tube being suitable for density modulation of the electron beam.

[0066] According to an embodiment of the present invention, the multi-mode overlapping interaction circuit further includes: an input waveguide 2, a first coupling structure 3, a second coupling structure 4, and an output waveguide 5. The input waveguide 2 is suitable for inputting a terahertz wave signal from the outside. The first coupling structure 3 is suitable for connecting the input waveguide and the input cavity unit 13, and a first coupling hole is formed on the first coupling structure 3, and the first coupling hole is suitable for outputting the terahertz wave signal from the input waveguide 2 to the input cavity unit 11. The second coupling structure 4 is connected to the output cavity unit, and a second coupling hole is formed on the second coupling structure 4, and the second coupling hole is suitable for transmitting the terahertz wave signal with increased power output by the output cavity. The output waveguide 5 is suitable for outputting the terahertz wave signal with increased frequency from the second coupling structure. An electron beam output port 131 is also provided in the output cavity unit 12, which is suitable for transmitting the electron beam whose energy is absorbed by the output cavity.

[0067] According to an embodiment of the present invention, for example, the length of the input waveguide 2 and the output waveguide 3 are both 0.51 mm, and the width is both 0.25 mm. The length of the upper and lower coupling holes of the input waveguide 2 and the output waveguide 3 are both 0.45 mm, the width is both 0.2 mm, and the height is both 0.2 mm. The number of trapezoidal units in each resonant cavity is N. The length of the five drift tubes is 0.44 mm. The current is 0.15 A. The magnetic induction intensity is 0.6 T. To ensure that the quality factor of all resonant modes of the input cavity and the external quality factor of all resonant modes of the output cavity are less than 1000, thereby increasing the power of the terahertz wave signal input to the resonant cavity unit 1, and increasing the output power of the terahertz wave signal from the resonant cavity unit 1, which is conducive to further expanding the bandwidth.

[0068] Specific embodiments are listed below to illustrate the multi-mode overlapping interaction klystron provided by the embodiments of the present invention.

[0069] refer to Figure 1-4 The multi-mode overlapping interaction circuit of the multi-mode overlapping interaction klystron includes an input cavity, four intermediate cavities, an output cavity, and five drift tubes. One side of the input cavity is an electron beam input port 112, and the other side is connected to the first intermediate cavity through the first drift tube. The input cavity is connected to the input waveguide 2 through a first coupling hole of a first coupling structure 3. The four intermediate cavities are connected in sequence through the second drift tube. One side of the output cavity is connected to the fourth intermediate cavity through the second drift tube, and the other side is an electron beam output port 131, which is used to connect the collector of the multi-mode overlapping interaction circuit, and is connected to the output waveguide 5 through the second output coupling hole of the second coupling structure 3.

[0070] The input cavity, the middle cavity and the output cavity include a plurality of trapezoidal structural units arranged in the axial direction, the period length between each group of adjacent trapezoidal structural units is the same, and the cavity contains fourteen trapezoidal structural units. The trapezoidal structural unit includes a first coupling cavity (i.e., an upper coupling cavity) 141-2, a second coupling cavity (i.e., a lower coupling cavity) 141-3 and a gap 141-5, the upper and lower coupling cavities are the same, and the center of the gap is an electron injection channel. The five-segment drift tube is a circular waveguide structure with an inner diameter the same as the radius of the electron injection channel. The coupling holes of the input cavity and the output cavity are the same and symmetrical in position. The input cavity, the middle cavity, the output cavity and the drift tube are all made of oxygen-free copper. For the input cavity, the middle cavity and the output cavity, the height of the upper and lower coupling cavities is 0.18 mm and the width is 0.4 mm, the width of the resonant gap is 0.6 mm and the height is 0.4 mm, the period length between adjacent gaps is 0.22 mm, and the radius of the electron injection channel is 0.11 mm. The length of the input waveguide 2 and the output waveguide 5 is 0.51 mm, and the width is 0.25 mm. The length of the coupling hole (including the first coupling hole and the second coupling hole) is 0.45 mm, the width is 0.2 mm, and the height is 0.2 mm. The length of the five drift tubes is 0.44 mm.

[0071] Under the above structural parameters, a multi-mode overlapping interaction circuit is obtained, and the dispersion curve of its resonant cavity (including input cavity, output cavity and intermediate cavity) is as follows: Figure 5 As shown. The multiple resonant modes of the cavity of the interaction klystron are the 2π mode and the adjacent π / 13 mode. The resonant frequencies corresponding to these two resonant modes are around 340 GHz and 338 GHz, respectively, and the corresponding synchronization voltages of the terahertz wave signals are 16.7 kV and 18.1 kV, respectively. When the electron beam voltage is between 16.7 kV and 18.1 kV, the electron beam and the two working modes can have effective beam-wave interaction. This is because there is a one-to-one correspondence between the synchronization voltage corresponding to the resonant mode and the phase velocity of the forward wave component in the resonant mode. When the electron beam dispersion line is located between the dispersion points of the two resonant modes, the electron beam interacts strongly with the fields of the two resonant modes. Therefore, when the electron beam voltage is between the synchronization voltages of the terahertz wave signals corresponding to the two resonant modes, the electron beam can interact with the resonant fields of the two resonant modes.

[0072] When the electron beam voltage is 17.85 kV, the electron beam current is 0.15 A, and the magnetic induction intensity used to focus the electron beam is 0.6 T. Figure 6 As shown, when driven by input powers of 10 mW, 50 mW and 150 mW, the 3 dB bandwidth of the klystron reaches 2.9 GHz, and the maximum gain is 25.9 dB, 25.3 dB and 23.4 dB respectively.

[0073] Figure 7The output power diagram of the terahertz wave signal at different frequencies obtained when the input terahertz wave signal power is 150mW, where the horizontal axis is the simulation time and the vertical axis is the power output by the output cavity. Figure 7 It can be seen that the terahertz interaction klystron provided by the embodiment of the present invention can output signals stably within a period of time without oscillation.

[0074] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A multi-mode overlapping interaction circuit for widening the bandwidth of a terahertz extended interaction klystron, comprising an input cavity unit, an intermediate cavity unit and an output cavity unit connected in sequence; An input cavity unit, wherein the input cavity unit is excited by a terahertz wave signal from the outside to generate a multi-mode overlapping resonance field; the multi-mode overlapping resonance field generated by the input cavity unit is suitable for interacting with an electron beam from the outside to modulate the electron beam from the outside; The intermediate cavity unit is adapted to generate a multi-mode overlapping resonance field under the excitation of the electron beam output by the input cavity unit, and the multi-mode overlapping resonance field generated by the intermediate cavity unit is adapted to interact with the electron beam output by the input cavity unit to modulate the electron beam output by the input cavity unit; An output cavity unit, adapted to generate a multi-mode overlapping resonance field under the excitation of the electron beam output by the intermediate cavity unit, wherein the multi-mode overlapping resonance field generated by the output cavity unit is adapted to interact with the electron beam output by the intermediate cavity unit so that the multi-mode overlapping resonance field generated by the output cavity absorbs energy from the electron beam output by the intermediate cavity unit, and outputs a terahertz wave signal with increased power; The input cavity unit, the intermediate cavity unit and the output cavity unit have the same multimode mode, the multimode mode includes multiple resonance modes, the absolute value of the difference between the resonance frequency corresponding to each of the multiple resonance modes and the operating frequency of the terahertz multimode overlapping interaction klystron and the operating frequency of the terahertz multimode overlapping interaction klystron are all less than or equal to 1%; the difference between the maximum value and the minimum value of the phase shift angle corresponding to each of the multiple resonance modes is less than or equal to The velocity of the electron beam is between the maximum value and the minimum value of the phase velocity of the forward wave components corresponding to each of the plurality of resonance modes.

2. The multi-mode overlapping interaction circuit according to claim 1, wherein: The input cavity unit includes an input cavity, and the input cavity includes a trapezoidal structure; the intermediate cavity unit includes 4 intermediate cavities, and each intermediate cavity includes the trapezoidal structure; the output cavity unit includes an output cavity, and the output cavity includes the trapezoidal structure; the trapezoidal structure includes 14 trapezoidal structure units arranged in sequence along the axial direction, and the 14 trapezoidal structure units form a periodic arrangement structure; the input cavity, the intermediate cavity and the output cavity have the multi-mode mode; Each of the trapezoidal structural units includes a trapezoidal structural unit body, on which a first coupling cavity, a second coupling cavity and an electron injection channel located between the first coupling cavity and the second coupling cavity are sequentially formed, and the first coupling cavity, the second coupling cavity and the electron injection channel are connected by a gap.

3. The multi-mode overlapping interaction circuit according to claim 2, wherein: The first coupling cavity has a height of 0.18 mm and a width of 0.4 mm, the second coupling cavity has a height of 0.18 mm and a width of 0.4 mm, the gap has a width of 0.6 mm and a height of 0.4 mm, the radius of the electron injection channel is 0.11 mm, and the period length of the periodic arrangement structure is 0.22 mm.

4. The multi-mode overlapping interaction circuit according to claim 2, wherein: The input cavity unit further includes a first drift tube, which is arranged between the input cavity and the intermediate cavity; the intermediate cavity unit further includes a plurality of second drift tubes, which are arranged between two adjacent intermediate cavities and between the intermediate cavity and the output cavity.

5. The multi-mode overlapping interaction circuit according to claim 2, wherein: The input cavity unit is also provided with an electron beam injection port, which is suitable for injecting an electron beam from the outside into the input cavity; the output cavity unit is also provided with an electron beam output port, which is suitable for transmitting the electron beam whose energy is absorbed by the output cavity.

6. The multi-mode overlapping interaction circuit according to claim 1, wherein: The quality factors of all the resonance modes of the input cavity and the external quality factors of all the resonance modes of the output cavity are both less than 1000.

7. The multi-mode overlapping interaction circuit according to claim 1, wherein: The multi-mode overlapping interaction circuit also includes: An input waveguide, suitable for inputting a terahertz wave signal from the outside; The first coupling structure is used to connect the input waveguide and the input cavity unit. A first coupling hole is formed on the first coupling structure. The first coupling hole is used to input the terahertz wave signal from the input waveguide into the input cavity unit.

8. The multi-mode overlapping interaction circuit according to claim 1, wherein: Also includes: a second coupling structure connected to the output cavity, wherein a second coupling hole is formed on the second coupling structure, and the second coupling hole is suitable for transmitting the terahertz wave signal with increased power output by the output cavity; The output waveguide is adapted to output the terahertz wave signal with increased power from the second coupling structure.

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