High-efficiency relativistic backward wave tube oscillator based on cavity matching

Abstract

The invention relates to a microwave source device in the technical field of high-power microwaves, in particular to a high-efficiency relativistic backward wave tube oscillator based on cavity matching, and belongs to the technical field of high-power microwaves. According to the invention, the front double-gap modulation cavity is adopted to inhibit microwaves from leaking to a diode area; the microwave conversion efficiency is improved by adopting a non-uniform rectangular slow wave structure; the microwave output power and the extraction efficiency are improved by adopting a double-gap extraction cavity structure; the C-band relativistic backward wave tube oscillator can overcome the difficulty that the conversion efficiency of a common C-band relativistic backward wave tube oscillator is difficult to break through 50%, and is simple in structure and easy to process.

Description

Technical Field

[0001] The invention relates to a microwave source device in the field of high-power microwave technology, in particular to a high-efficiency relativistic backward wave tube oscillator based on cavity matching, belonging to the field of high-power microwave technology. Background Art

[0002] High-power microwaves are usually defined as electromagnetic waves with a peak power of more than 100 MW and a frequency of 1 GHz to 300 GHz. It is an interdisciplinary subject of plasma physics, pulse power technology, and physical electronics, and has broad application prospects in cutting-edge fields such as plasma thermonuclear fusion, high-power radar, and high-energy radio frequency acceleration.

[0003] A high-power microwave source refers to a device in a high-power microwave system that converts the energy of a strong relativistic electron beam into microwave energy, that is, a device that generates high-power microwaves. The relativistic Cherenkov oscillator is one of the most promising high-power microwave source devices. It uses the interaction between a strong relativistic electron beam and a high-frequency electromagnetic structure to generate Cherenkov radiation, which then self-oscillates to generate high-power microwaves. When the electromagnetic wave in the slow-wave structure is a backward wave, this type of relativistic Cherenkov oscillator is called a relativistic backward wave tube oscillator. At present, how to achieve a high-efficiency output relativistic backward wave tube oscillator is still the focus of the industry.

[0004] In 2010, Zhang Jun and others from the National University of Defense Technology studied a C-band resonant relativistic backward wave oscillator [Zhang Jun, Jin Zhenxing, Zhong Huihuang, et al. Design of C-band resonant relativistic backward wave oscillator and its high-frequency characteristics [J]. High Power Laser and Particle Beams, 2010, 22(10).] (hereinafter referred to as prior art 1, such as Figure 1 As shown). The structure consists of an annular cathode 101, a cutoff neck 102, an inserted waveguide 103, a slow-wave structure 104, a reflector 105, a conical waveguide 106 and a collector 107. The entire device is rotationally symmetrical about the center. This scheme adjusts the phase difference between the -1 return wave and the forward fundamental wave by adding a smooth waveguide between the slow-wave structure and the cutoff neck. Different phase differences will affect the effect of beam-wave interaction. Under the conditions of a guiding magnetic field of 2.5T, a diode voltage of 780kV and a current of 7.8kA, the C-band microwave with an output power of 1.5GW has a conversion efficiency of only 25%. The operating voltage and current of this scheme are large, and the slow-wave structure has fewer cycles, resulting in low conversion efficiency, which needs to be further improved.

[0005] In 2018, Cao Yibing and others from the Northwest Institute of Nuclear Technology studied a C-band long pulse relativistic backward wave tube device [Cao Yibing, Sun Jun, Song Zhimin, et al. Design and experiment of C-band long pulse relativistic backward wave tube [J]. High Power Laser and Particle Beams, 2018, 30(05): 53-56.]. (hereinafter referred to as prior art 2, such as Figure 2 ). The structure consists of an annular cathode 201, a trapezoidal resonant reflector 202, a non-uniform trapezoidal slow-wave structure 203, a trapezoidal extraction cavity 204, a coaxial collector 205, and an output waveguide 206. Under the conditions of a diode operating voltage of 800 kV and a current of 9.7 kA, the output microwave power is about 3.7 GW, the efficiency is about 47.7%, and the operating frequency is 4.27 GHz.

[0006] Analyzing the above research status, it is not difficult to see that the efficiency of C-band relativistic backward-wave tube oscillator is still difficult to exceed 50%. How to achieve an efficiency greater than 50% is an urgent problem to be solved. Summary of the invention

[0007] The technical problem to be solved by the present invention is: the present invention provides a high-efficiency relativistic backward wave tube oscillator based on cavity matching, adopts a front double-gap modulation cavity to suppress microwave leakage to the diode area; adopts a non-uniform rectangular slow wave structure to improve microwave conversion efficiency; and adopts a double-gap extraction cavity structure to improve microwave output power and extraction efficiency. The present invention can overcome the difficulty that the conversion efficiency of a conventional C-band relativistic backward wave tube oscillator is difficult to break through 50%, and has a simple structure and is easy to process.

[0008] The technical solution of the present invention is: A high-efficiency relativistic backward wave tube oscillator based on cavity coordination includes a cathode seat 301, a cathode 302, an anode outer cylinder 303, a double-gap modulation cavity 304, an inhomogeneous slow-wave structure 305, a drift cavity 306, a double-gap extraction cavity 307, an output waveguide 308 and a solenoid magnetic field 309; the entire structure is rotationally symmetric about the central axis.

[0009] The inner surface of the anode outer cylinder 303 has irregular corrugations, forming a high-frequency structure; the double-gap modulation cavity 304 is composed of two resonant cavities in cascade, and the outer radius of the first modulation cavity is R 3 , the inner radius is R 2 , satisfying R 3 >R 2 , width L 2 , L 2 The value is 0.2-0.4 times of the working wavelength λ, and the radius R is between the two modulation cavities. 2 , width L 3 The disc connection, L 3 The value is 0.2-0.4 times of the working wavelength λ, and the outer radius of the second modulation cavity is R4 , the inner radius is R 2 , satisfying R 3 >R 4 , width L 4 , L 4 The value is 0.3-0.5 times of the working wavelength λ, L 2 , L 3 , L 4 Meet L 4 >L 2 >L 3 There is a radius R between the non-uniform slow-wave structure 305 and the double-gap modulation cavity 304. 2 , width L 5 The disc connection, L 5 The value is 0.2-0.4 times of the working wavelength λ; the non-uniform slow-wave structure 305 is composed of two sections of slow-wave structures: the first section of the slow-wave structure includes three slow-wave blades, the cross section of the first slow-wave blade is a right-angle trapezoid, and the outer radius is R 5 , the inner radius is R 6 , the length of the upper base is L 6 , the length of the hypotenuse projection is L 31 ; The radius R is between the first slow wave blade and the second slow wave blade. 6 , width L 7 The disc connection, L 7 The value is 3mm-10mm; the second slow wave blade is trapezoidal, with an outer radius of R 7 , satisfying R 7 >R 6 , the inner radius is R 2 , the length of the upper base is L 8 , the length of the left hypotenuse projection is L 32 , the length of the right hypotenuse is L 33 , satisfying L 8 <L 7 , L 32 =L 33 ; The radius R is between the second slow wave blade and the third slow wave blade. 2 , width L 9 The disc connection, L 9 The value is 1mm-10mm; the outer radius of the third trapezoidal slow-wave blade is R 8 , the inner radius is R 7 , satisfying R 8 >R 7 , the length of the upper base is L 10 , satisfying L 8 <L 10 , the length of the left hypotenuse projection is L 34 , the length of the right hypotenuse projection is L 35 , satisfying L 34=L 35 The third slow wave blade and the drift cavity 306 are separated by a radius of R 6 , width L 11 The disc connection, L 11 The value is 1mm-10mm; the outer radius of the drift cavity 306 is R 9 , satisfying R 9 <R 8 , the inner radius is R 2 , the length of the upper base is L 12 , the length of the left hypotenuse projection is L 36 , the length of the right hypotenuse projection is L 37 , satisfying L 36 =L 37 The second slow wave structure is composed of four slow wave blades, and the fourth slow wave blade and the drift cavity 306 are separated by a radius of R 2 , width L 13 The disc connection, L 13 The value is 1mm-10mm; the outer radius of the fourth trapezoidal slow-wave blade is R 10 , the inner radius is R 6 , the length of the upper base is L 14 , satisfying L 14 =L 13 , the length of the left hypotenuse projection is L 38 , the length of the right hypotenuse projection is L 39 , satisfying L 38 =L 39 ; The fourth slow wave blade and the fifth slow wave blade are separated by a radius of R 6 , width L 15 The disc connection, L 15 The value is 1mm-10mm; the outer radius of the fifth slow-wave blade is R 11 , satisfying R 10 <R 11 , the inner radius is R 6 , the length of the upper base is L 16 , satisfying L 16 >L 15 , the length of the left hypotenuse projection is L 40 , the right hypotenuse projection is L 41 , satisfying L 40 =L 41 ; The radius R is between the fifth slow wave blade and the sixth slow wave blade. 2 , length L 17 The outer radius of the sixth slow-wave blade is R 12 , length L 18 , the inner radius is R 2 , the length of the left hypotenuse projection is L 42 , the length of the right hypotenuse projection is L43 , satisfying L 42 =L 43 ; The radius R is between the sixth slow wave blade and the seventh slow wave blade. 2 , length L 19 The seventh slow-wave blade has a rectangular cross section with an outer radius of R. 13 , length L 20 , the inner radius is R 6 , the length of the hypotenuse projection is L 44 The radius R is between the non-uniform slow-wave structure 305 and the double-gap extraction cavity 307. 6 , length L 45 The first extraction chamber of the double gap extraction chamber 307 is a radius of R 14 , the cross section is rectangular and the length is L 21 The second extraction cavity is a circular cavity with a radius of R 15 , the cross section is rectangular and the length is L 22 The two extraction chambers are separated by a ring-shaped cavity with a length of L 45 Disc connection.

[0010] The cathode 302 is a thin-walled cylinder with a wall thickness of 2 mm and a radius of R. 1 , sleeved on the right end of the cathode seat 301.

[0011] All parameters of the double-gap modulation cavity 304 need to be optimized as a whole according to the working wavelength λ, so that the generated microwaves cannot be transmitted back to the cathode region.

[0012] All parameters of the non-uniform slow-wave structure 305 need to be optimized as a whole according to the working wavelength λ to ensure that the electron beam can fully interact with the slow-wave structure to generate Cherenkov radiation.

[0013] All parameters of the double-gap extraction cavity 307 need to be optimized as a whole according to the working wavelength λ, so that the generated microwaves cannot be transmitted back to the cathode emission area, and at the same time, the position where the electron beam clustering is strongest appears near the double-gap extraction cavity.

[0014] The output waveguide 308 is the right radius R of the double gap extraction cavity 307 2 Circular waveguide for output TM 01 mode of high power microwaves.

[0015] The solenoid magnetic field 309 is a magnetic field formed by winding a solenoid coil. By changing the current passing through the solenoid coil, the intensity of the magnetic field generated by the solenoid coil is changed, thereby achieving transmission guidance of the electron beam.

[0016] The working process of the present invention is as follows: the pulse voltage generated by the pulse power driving source acts on the cathode 302 through the cathode seat 301, and the right end face of the cathode 302 generates a strong relativistic electron beam based on explosive emission, which is transmitted to the high-frequency structure under the guidance of the solenoid magnetic field 309. The electron beam passes through the double-gap modulation cavity 304, the non-uniform slow-wave structure 305, the drift cavity 306 and the double-gap extraction cavity 307 respectively, and finally bombards the inner wall of the output waveguide 308; the generated microwave radiates outward through the output waveguide 308.

[0017] Compared with the prior art, the present invention can achieve the following technical effects: 1. The high-efficiency relativistic backward wave tube oscillator based on cavity coordination provided by the present invention adopts a double-gap modulation cavity and a double-gap extraction cavity. The coordinated use of the two types of cavities enables the generated microwaves to further modulate the electron beam, and makes the position where the electron beam clustering is strongest appear near the double-gap extraction cavity. After being fully decelerated by the axial electric field, the beam power is concentratedly converted into transition radiation, and ultimately a conversion efficiency greater than 50% can be obtained.

[0018] 2. The high-efficiency relativistic backward-wave tube oscillator based on cavity coordination provided by the present invention adopts a double-gap modulation cavity. The reflection coefficient of the double-gap modulation cavity can reach 0.997, which can effectively suppress the leakage of reverse microwaves to the diode area. At the same time, the electric field in the double-gap modulation cavity can also pre-modulate the electron beam, which is beneficial to the clustering of the electron beam, thereby improving the conversion efficiency.

[0019] 3. The high-efficiency relativistic backward wave tube oscillator based on cavity matching provided by the present invention adopts a double-gap extraction cavity, which can strengthen the local axial electric field and further decelerate the electron beam, thereby improving the microwave output power and conversion efficiency. The double-gap extraction cavity can also reflect part of the microwave to the slow-wave structure area, thereby increasing the modulation depth. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of a C-band resonant relativistic backward wave oscillator disclosed in the prior art 1 in the background introduction; Figure 2 A schematic diagram of the structure of a C-band long pulse relativistic backward wave tube oscillator disclosed in the prior art 2 in the background introduction; Figure 3 A cross-sectional view of a preferred embodiment of a high-efficiency relativistic backward wave tube oscillator based on cavity matching provided by the present invention; Figure 4 The S of the double-gap reflection cavity used in the preferred embodiment of the high-efficiency relativistic backward wave tube oscillator based on cavity matching provided by the present invention 11 Graph of parameter variation with frequency; Figure 5An input power diagram of a preferred embodiment of a high-efficiency relativistic backward wave tube oscillator based on cavity matching provided by the present invention; Figure 6 An output spectrum diagram of a preferred embodiment of a high-efficiency relativistic backward wave tube oscillator based on cavity matching provided by the present invention; Figure 7 A graph showing the variation of the output power over time of a preferred embodiment of a high-efficiency relativistic backward wave tube oscillator based on cavity matching provided by the present invention; Figure 8 The preferred embodiment of the high-efficiency relativistic backward wave tube oscillator based on cavity matching provided by the present invention adopts a non-uniform slow wave structure and the conversion efficiency varies with the drift cavity length L 12 ; Fig. 9 A comparison diagram of fundamental wave current when a single modulation cavity and a double modulation cavity are loaded respectively for a preferred embodiment of a high-efficiency relativistic backward wave tube oscillator based on cavity matching provided by the present invention; Fig.10 A comparison diagram of the electron power distribution when a single extraction cavity and a double extraction cavity are loaded respectively for a preferred embodiment of a high-efficiency relativistic backward wave tube oscillator based on cavity matching provided by the present invention; Fig.11 A comparison diagram of the output microwave power of a preferred embodiment of a high-efficiency relativistic backward wave tube oscillator based on cavity matching provided by the present invention when a single modulation cavity and a double modulation cavity are loaded respectively; Fig.12 A comparison diagram of the output microwave powers of a preferred embodiment of a high-efficiency relativistic backward wave tube oscillator based on cavity matching provided by the present invention when loaded with a single extraction cavity and a double extraction cavity respectively. DETAILED DESCRIPTION

[0021] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0022] The present invention is composed of a cathode seat 301, a cathode 302, an anode outer cylinder 303, a double-gap modulation cavity 304, a non-uniform slow wave structure 305, a drift cavity 306, a double-gap extraction cavity 307, an output waveguide 308 and a solenoid magnetic field 309. The entire structure is rotationally symmetric about the central axis.

[0023] The cathode seat 301 and the anode outer tube 303 are usually made of non-magnetic stainless steel, the cathode 302 can be made of high-hardness graphite or heat-resistant glass cloth-epoxy resin copper-clad foil (FR-5) material, and the solenoid magnetic field 309 is made of enameled copper wire or glass fiber copper wire. The left end of the cathode seat 301 is connected to the inner conductor of the pulse power driving source, and the left end of the anode outer tube 303 is connected to the outer conductor of the pulse power driving source.

[0024] When the present invention is in operation, the front-stage pulse power source will be loaded onto the cathode seat 301, and the cathode 302 will generate an annular high-current relativistic particle beam. The high-current relativistic particle beam will be subjected to initial velocity modulation in the double-gap modulation cavity 304, and will be further velocity modulated in the first few blades of the non-uniform slow-wave structure 305. The high-current relativistic particle beam will begin to be converted into density modulation when passing through the drift cavity 306, forming a cluster of electron beams, and then when passing through the second section of the non-uniform slow-wave structure 305, the clustered electron beam will interact with the microwave field to generate Cherenkov radiation and hand over energy to the microwave; when passing through the double-gap extraction cavity 307, the clustered electron beam will be decelerated by the axial electric field, thereby generating concentrated transition radiation, and the microwave output power will be further improved.

[0025] This embodiment realizes a high-efficiency relativistic backward wave tube oscillator based on cavity matching with an operating frequency of 7.80 GHz (corresponding to a microwave wavelength λ=3.83 cm), and the corresponding size design is: R 1 =23mm, R 2 =28mm, R 3 =34mm, R 4 =30.5mm, R 5 =34mm, R 6 =29mm, R 7 =33.5mm, R 8 =34mm, R 9 =31mm, R 10 =35mm, R 11 =35.5mm, R 12 =35mm, R 13 =34.5mm, R 14 =37mm, R 15 =35mm, L 1 =3mm, L 2 =11.5mm, L 3 =10.5mm, L 4 =13mm, L 5 =8mm, L 6 =5mm, L 7 =5mm, L 8 =3mm, L 9 =4.5mm, L 10 =4.5mm, L 11 =4mm, L 12 =13mm, L 13 =4mm, L 14 =4mm, L 15 =2.5mm, L 16 =3.5mm, L 17 =3mm, L18 =3.5mm, L 19 =3mm, L 20 =3.5mm, L 21 =3.5mm, L 22 =5mm, L 31 =4mm, L 32 =4mm, L 33 =4mm, L 34 =4mm, L 35 =4mm, L 36 =5mm, L 37 =5mm, L 38 =4mm, L 39 =4mm, L 40 =3mm, L 41 =3mm, L 42 =3mm, L 43 =3mm, L 44 =9mm, L 45 =6.5mm, L 46 =3mm.

[0026] In the particle simulation, under the conditions of diode voltage of 468kV, current of 5.7kA and guiding magnetic field of 0.7 T, high-power microwaves with an output frequency of 7.80GHz were output, the output microwave power was 1.87GW and the conversion efficiency reached 53%.

[0027] See also Figure 4 , it can be seen that the reflection coefficient S of the double-gap reflection cavity used by the oscillator at the operating frequency of 7.80GHz 11 It is 0.997, which can effectively isolate the slow-wave structure area and the diode area, thereby improving the conversion efficiency.

[0028] See also Figure 5 , it can be seen that the input power of the oscillator is 3.48GW.

[0029] See also Figure 6 It can be seen that the frequency of the output microwave of the oscillator is 7.80GHz, the spectrum is pure, and the frequency multiplication is small.

[0030] See also Figure 7 , it can be seen that the output microwave power of the oscillator is 1.84GW.

[0031] See also Figure 8 It can be seen that when the non-uniform rectangular slow-wave structure is loaded, the output microwave conversion efficiency of the oscillator will be affected by the drift cavity length L 12 The influence of L 12 With the increase of L 12The best value is 13mm, at which the conversion efficiency reaches the highest, which is 53%.

[0032] See also Fig. 9 It can be seen that compared with loading a single modulation cavity, the device has a stronger modulation effect on the electron beam after loading a double-gap modulation cavity, and the electron beam clustering near the extraction cavity is stronger, which makes the device have a higher beam-to-wave conversion efficiency.

[0033] See also Fig.10 It can be seen that compared with loading a single extraction cavity, loading a double-gap extraction cavity can convert more beam power into transition radiation, thereby improving the conversion efficiency.

[0034] See also Fig.11 It can be seen that compared with loading a single modulation cavity, the output microwave power is greatly improved when loading a double-gap modulation cavity, indicating that the double-gap modulation cavity has a stronger modulation effect on the electron beam, thereby improving the beam-wave conversion efficiency.

[0035] See also Fig.12 It can be seen that compared with loading a single extraction cavity, the output microwave power is greatly improved when loading a double-gap extraction cavity, indicating that the double-gap extraction cavity can greatly enhance the transition radiation generated by the electron beam, thereby significantly improving the beam-wave conversion efficiency.

Claims

1. A high-efficiency relativistic backward wave tube oscillator based on cavity matching, characterized by: It includes a cathode seat (301), a cathode (302), an anode outer cylinder (303), a double-gap modulation cavity (304), a non-uniform slow wave structure (305), a drift cavity (306), a double-gap extraction cavity (307), an output waveguide (308) and a solenoid magnetic field (309); the entire structure is rotationally symmetric about the central axis; The double-gap modulation cavity (304) is composed of two cascaded resonant cavities, wherein the first modulation cavity has an outer radius of R3, an inner radius of R2, satisfying R3>R2, and a width of L2, wherein L2 is 0.2-0.4 times of the working wavelength λ; the two modulation cavities are connected by a disk having a radius of R2 and a width of L3, wherein L3 is 0.2-0.4 times of the working wavelength λ; the second modulation cavity has an outer radius of R4, an inner radius of R2, satisfying R3>R4, and a width of L4, wherein L4 is 0.3-0.5 times of the working wavelength λ; L2, L3, and L4 satisfy L4>L2>L3; the first extraction cavity of the double-gap extraction cavity (307) is a cavity having a radius of R 14 , the cross section is rectangular and the length is L 21 The second extraction cavity is a circular cavity with a radius of R 15 , the cross section is rectangular and the length is L 22 The two extraction chambers are separated by a ring-shaped cavity with a length of L 45 Disc connection.

2. The high-efficiency relativistic backward wave tube oscillator based on cavity matching according to claim 1, characterized in that: The cathode (302) is a thin-walled cylinder with a wall thickness of 2 mm and a radius of R1, and is sleeved on the right end of the cathode seat (301).

3. The high-efficiency relativistic backward wave tube oscillator based on cavity matching according to claim 1, characterized in that: All parameters of the double-gap modulation cavity (304) need to be optimized as a whole according to the working wavelength so that the generated microwaves cannot be transmitted back to the cathode region.

4. The high-efficiency relativistic backward wave tube oscillator based on cavity matching according to claim 1, characterized in that: All parameters of the non-uniform slow-wave structure (305) need to be optimized overall according to the working wavelength to ensure that the electron beam can fully interact with the slow-wave structure to generate Cherenkov radiation.

5. The high-efficiency relativistic backward wave tube oscillator based on cavity matching according to claim 1, characterized in that: All parameters of the double-gap extraction cavity (307) need to be optimized as a whole according to the working wavelength, so that the generated microwaves cannot be transmitted back to the cathode emission area, and at the same time, the position where the electron beam clustering is strongest appears near the double-gap extraction cavity.

6. The high-efficiency relativistic backward wave tube oscillator based on cavity matching according to claim 1, characterized in that: The non-uniform slow-wave structure (305) is connected to the double-gap modulation cavity (304) by a disk with a radius of R2 and a width of L5, where L5 ranges from 0.2 to 0.4 times the operating wavelength λ; the non-uniform slow-wave structure (305) consists of two sections of slow-wave structures: the first section of the slow-wave structure includes three slow-wave vanes. The cross-section of the first slow-wave vane is a right trapezoid, with an outer radius of R5, an inner radius of R6, an upper base length of L6, and the length of the projection of the hypotenuse being L 31 ; the first slow-wave vane and the second slow-wave vane are connected by a disk with a radius of R6 and a width of L7, where L7 ranges from 3 mm to 10 mm; the second slow-wave vane is trapezoidal, with an outer radius of R7, where R7 > R6, an inner radius of R2, an upper base length of L8, and the length of the projection of the left hypotenuse being L 32 , and the length of the right hypotenuse being L 33 , where L8 < L7, L 32 = L 33 ; the second slow-wave vane and the third slow-wave vane are connected by a disk with a radius of R2 and a width of L9, where L9 ranges from 1 mm to 10 mm; the outer radius of the third trapezoidal slow-wave vane is R8, the inner radius is R7, where R8 > R7, and the upper base length is L 10 , where L8 < L 10 , the length of the projection of the left hypotenuse is L 34 , and the length of the projection of the right hypotenuse is L 35 , where L 34 = L 35 ; the third slow-wave vane and the drift cavity (306) are connected by a disk with a radius of R6 and a width of L 11 , where L 11 ranges from 1 mm to 10 mm; the outer radius of the drift cavity (306) is R9, where R9 < R8, the inner radius is R2, and the upper base length is L 12 , the length of the projection of the left hypotenuse is L 36 , and the length of the projection of the right hypotenuse is L 37 , where L 36 = L 37 ; the second section of the slow-wave structure consists of four slow-wave vanes. The fourth slow-wave vane and the drift cavity (306) are connected by a disk with a radius of R2 and a width of L 13 , where L 13 ranges from 1 mm to 10 mm; the outer radius of the fourth trapezoidal slow-wave vane is R 10 , the inner radius is R6, and the upper base length is L 14 , where L 14 = L 13 , the length of the projection of the left hypotenuse is L 38 , and the length of the projection of the right hypotenuse is L 39 , where L 38 = L 39 ; The fourth slow wave blade and the fifth slow wave blade are separated by a radius of R6 and a width of L 15 The disc connection, L 15 The value is 1mm-10mm; the outer radius of the fifth slow-wave blade is R 11 , satisfying R 10 <R 11 , the inner radius is R6, the length of the upper base is L 16 , satisfying L 16 >L 15 , the length of the left hypotenuse projection is L 40 , the right hypotenuse projection is L 41 , satisfying L 40 =L 41 ; The fifth slow wave blade and the sixth slow wave blade are separated by a radius R2 and a length L 17 The outer radius of the sixth slow-wave blade is R 12 , length L 18 , the inner radius is R2, and the left hypotenuse projection length is L 42 , the length of the right hypotenuse projection is L 43 , satisfying L 42 =L 43 ; The sixth slow wave blade and the seventh slow wave blade are separated by a radius R2 and a length L 19 The seventh slow-wave blade has a rectangular cross section with an outer radius of R. 13 , length L 20 , the inner radius is R6, and the hypotenuse projection length is L 44 The non-uniform slow wave structure (305) and the double gap extraction cavity (307) are separated by a radius R6 and a length L 45 Disc connection.

7. The high-efficiency relativistic backward wave tube oscillator based on cavity matching according to claim 1, characterized in that: The output waveguide (308) is a circular waveguide with a radius R2 on the right side of the double-gap extraction cavity (307) and is used to output TM 01 mode of high power microwaves.

8. The high-efficiency relativistic backward wave tube oscillator based on cavity matching according to claim 1, characterized in that: The solenoid magnetic field (309) is a magnetic field formed by winding a solenoid coil. By changing the magnitude of the current passing through the solenoid coil, the intensity of the magnetic field generated by the solenoid coil is changed, thereby achieving transmission guidance of the electron beam.

9. The high-efficiency relativistic backward wave tube oscillator based on cavity matching according to claim 1, characterized in that: The cathode seat (301) and the anode outer cylinder (303) are made of non-magnetic stainless steel, the cathode (302) is made of high-hardness graphite or heat-resistant glass cloth-epoxy resin copper foil plate material, and the solenoid magnetic field (309) is wound with enameled copper wire or glass fiber copper wire.

10. The high-efficiency relativistic backward wave tube oscillator based on cavity matching according to any one of claims 1 to 9, characterized in that: The working frequency is 7.80GHz, corresponding to the microwave wavelength = 3.83cm. A high-efficiency relativistic backward wave tube oscillator based on cavity matching has the following dimensions: R1 = 23mm, R2 = 28mm, R3 = 34mm, R4 = 30.5mm, R5 = 34mm, R6 = 29mm, R7 = 33.5mm, R8 = 34mm, R9 = 31mm, R 10 =35mm, R 11 =35.5mm, R 12 =35mm, R 13 =34.5mm, R 14 =37mm, R 15 =35mm, L1=3mm, L2=11.5mm, L3=10.5mm, L4=13mm, L5=8mm, L6=5mm, L7=5mm, L8=3mm, L9=4.5mm, L 10 =4.5mm, L 11 =4mm, L 12 =13mm, L 13 =4mm, L 14 =4mm, L 15 =2.5mm, L 16 =3.5mm, L 17 =3mm, L 18 =3.5mm, L 19 =3mm, L 20 =3.5mm, L 21 =3.5mm, L 22 =5mm, L 31 =4mm, L 32 =4mm, L 33 =4mm, L 34 =4mm, L 35 =4mm, L 36 =5mm, L 37 =5mm, L 38 =4mm, L 39 =4mm, L 40 =3mm, L 41 =3mm, L 42 =3mm, L 43 =3mm, L 44 =9mm, L 45 =6.5mm, L 46 =3mm.

Images