High-efficiency relativistic backward wave oscillator based on cavity matching

Abstract

The present invention relates to a microwave source device in the field of high-power microwave technology, in particular to a high-efficiency relativistic backward wave oscillator based on cavity cooperation, belonging to the field of high-power microwave technology; the present invention uses a pre-stage double-gap modulation cavity to suppress the leakage of microwaves to the diode region; uses a non-uniform rectangular slow-wave structure to improve the microwave conversion efficiency; uses a double-gap extraction cavity structure to improve the 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 oscillator is difficult to exceed 50%, and has a simple structure and is easy to process.

Description

Technical Field

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

[0002] High-power microwaves are generally defined as electromagnetic waves with a peak power exceeding 100 MW and a frequency in the range of 1 GHz to 300 GHz. It belongs to an interdisciplinary field of plasma physics, pulsed power technology, and physical electronics, and has broad application prospects in frontier 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 high-current relativistic electron beam into microwave energy, that is, generates high-power microwaves. The relativistic Cherenkov oscillator is one of the most promising high-power microwave source devices at present. It uses the interaction between a high-current relativistic electron beam and a high-frequency electromagnetic structure to generate Cherenkov radiation, and then self-excites 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 oscillator. Currently, how to achieve a relativistic backward wave oscillator with high-efficiency output remains the focus of attention in the industry.

[0004] In 2010, Zhang Jun et al. from the National University of Defense Technology studied a C-band resonant relativistic backward wave tube [Zhang Jun, Jin Zhenxing, Zhong Huihuang, etc. 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 the prior art 1, as Figure 1 shown). This structure consists of an annular cathode 101, a cut-off 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 symmetric about the center. This scheme adjusts the phase difference between the -1st backward wave and the forward fundamental wave by adding a smooth waveguide between the slow-wave structure and the cut-off neck. Different phase differences will affect the effect of the beam-wave interaction. Under the conditions of a guiding magnetic field of 2.5 T, a diode voltage of 780 kV, and a current of 7.8 kA, C-band microwaves with an output power of 1.5 GW are generated, and the conversion efficiency is only 25%. This scheme has a relatively high operating voltage and operating current, and the small period of the slow-wave structure results in a low conversion efficiency, which still needs to be further improved.

[0005] In 2018, Cao Yibing et al. 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 the prior art 2, as Figure 2 shown). This 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 approximately 3.7 GW, the efficiency is approximately 47.7%, and the operating frequency is 4.27 GHz.

[0006] Analyzing the above research status, it is not difficult to see that at present, it is still very difficult for the efficiency of C-band relativistic backward wave tube oscillators 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 cooperation, which uses a pre-positioned double-gap modulation cavity to suppress the leakage of microwaves to the diode region; uses a non-uniform rectangular slow-wave structure to improve the microwave conversion efficiency; and uses a double-gap extraction cavity structure to improve the 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:

[0009] A high-efficiency relativistic backward wave tube oscillator based on cavity cooperation, comprising a cathode base 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.

[0010] 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 cascaded resonant cavities. The outer radius of the first modulation cavity is R3, the inner radius is R2, where R3 > R2, and the width is L2. The value of L2 is 0.2 - 0.4 times the operating wavelength λ. The two modulation cavities are connected by a disk with a radius of R2 and a width of L3. The value of L3 is 0.2 - 0.4 times the operating wavelength λ. The outer radius of the second modulation cavity is R4, the inner radius is R2, where R3 > R4, and the width is L4. The value of L4 is 0.3 - 0.5 times the operating wavelength λ. L2, L3, and L4 satisfy L4 > L2 > L3; 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. The value of L5 is 0.2 - 0.4 times the operating 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 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 projected length of the hypotenuse is 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. The value of L7 is 3 mm - 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 projected length of the left hypotenuse is L 32 , and the length of the right hypotenuse is 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. The value of L9 is 1 mm - 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 , and the projected length of the left hypotenuse is L 34 , and the projected length 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 , and the value of L 11 is 1 mm - 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 , and the projected length of the left hypotenuse is L 36 , and the projected length of the right hypotenuse is L 37 , where L 36 = L 37 ; The second section of the slow-wave structure is composed 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 13The disk connection, L 13 The value ranges from 1 mm to 10 mm; the outer radius of the fourth trapezoidal slow-wave blade is R 10 , the inner radius is R6, and the length of the upper base is L 14 , satisfying L 14 = L 13 , the length of the projection of the left hypotenuse is L 38 , the length of the projection of the right hypotenuse is L 39 , satisfying L 38 = L 39 ; between the fourth slow-wave blade and the fifth slow-wave blade is connected by a disk with a radius of R6 and a width of L 15 , L 15 The value ranges from 1 mm to 10 mm; the outer radius of the fifth slow-wave blade is R 11 , satisfying R 10 < R 11 , the inner radius is R6, and the length of the upper base is L 16 , satisfying L 16 > L 15 , the length of the projection of the left hypotenuse is L 40 , the projection of the right hypotenuse is L 41 , satisfying L 40 = L 41 ; between the fifth slow-wave blade and the sixth slow-wave blade is connected by a disk with a radius of R2 and a length of L 17 ; the outer radius of the sixth slow-wave blade is R 12 , and the length is L 18 , the inner radius is R2, and the length of the projection of the left hypotenuse is L 42 , the length of the projection of the right hypotenuse is L 43 , satisfying L 42 = L 43 ; between the sixth slow-wave blade and the seventh slow-wave blade is connected by a disk with a radius of R2 and a length of L 19 ; the cross-section of the seventh slow-wave blade is a right-angled rectangle, the outer radius is R 13 , and the length is L 20 , the inner radius is R6, and the length of the projection of the hypotenuse is L 44 ; between the non-uniform slow-wave structure 305 and the double-gap extraction cavity 307 is connected by a disk with a radius of R6 and a length of L 45 ; the first extraction cavity of the double-gap extraction cavity 307 is a circular ring cavity with a radius of R 14 , the cross-section is rectangular, and the length is L 21 ; the second extraction cavity is a circular ring cavity with a radius of R 15 , the cross-section is rectangular, and the length is L 22 ; between the two extraction cavities is connected by a disk with a length of L 45 .

[0011] The cathode 302 is a thin-walled cylinder with a wall thickness of 2 mm and a radius of R1, which is sleeved on the right end of the cathode holder 301.

[0012] All parameters of the double-gap modulation cavity 304 need to be optimized as a whole according to the operating wavelength λ, so that the generated microwaves cannot be transmitted back to the cathode region.

[0013] All parameters of the non-uniform slow-wave structure 305 need to be optimized as a whole according to the operating wavelength λ to ensure that the electron beam can interact fully with the slow-wave structure, thereby generating Cherenkov radiation.

[0014] All parameters of the double-gap extraction cavity 307 need to be optimized as a whole according to the operating wavelength λ, so that the generated microwaves cannot be transmitted back to the cathode emission region, and at the same time, the position where the electron beam bunching is the strongest appears near the double-gap extraction cavity.

[0015] The output waveguide 308 is a circular waveguide with a radius of R2 on the right side of the double-gap extraction cavity 307, which is used to output high-power microwaves in the TM 01 mode.

[0016] 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 magnetic field intensity generated by the solenoid coil is changed, so as to realize the transmission and guidance of the electron beam.

[0017] The working process of the present invention is as follows: The pulsed voltage generated by the pulsed power driving source acts on the cathode 302 through the cathode holder 301. A high-current relativistic electron beam is generated on the right end face of the cathode 302 based on explosive emission and 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 microwaves are radiated out through the output waveguide 308.

[0018] Compared with the prior art, the following technical effects can be achieved by adopting the present invention:

[0019] 1. The high-efficiency relativistic backward wave oscillator based on cavity cooperation provided by the present invention adopts a double-gap modulation cavity and a double-gap extraction cavity. The combined 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 bunching is the strongest appear near the double-gap extraction cavity. After being sufficiently decelerated by the axial electric field, the beam power is concentrated and converted into transition radiation, and finally a conversion efficiency greater than 50% can be obtained.

[0020] 2. The high-efficiency relativistic backward wave oscillator based on cavity cooperation 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 backward microwaves to the diode region. 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 bunching of the electron beam and thus improves the conversion efficiency.

[0021] 3. The high-efficiency relativistic backward wave oscillator based on cavity cooperation provided by the present invention adopts a double-gap extraction cavity. The double-gap extraction cavity 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 microwaves to the slow-wave structure region, thereby improving the modulation depth. Brief Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of a C-band resonant relativistic backward wave oscillator disclosed in the prior art 1 in the background introduction;

[0023] Figure 2 It is a schematic structural diagram of a C-band long-pulse relativistic backward wave oscillator disclosed in the prior art 2 in the background introduction;

[0024] Figure 3 It is a sectional view of a preferred embodiment of the high-efficiency relativistic backward wave oscillator based on cavity cooperation provided by the present invention;

[0025] Figure 4 It is a graph of the S 11 parameter of the double-gap reflection cavity adopted in the preferred embodiment of the high-efficiency relativistic backward wave oscillator based on cavity cooperation provided by the present invention varying with frequency;

[0026] Figure 5 It is an input power graph of the preferred embodiment of the high-efficiency relativistic backward wave oscillator based on cavity cooperation provided by the present invention;

[0027] Figure 6 It is an output spectrum graph of the preferred embodiment of the high-efficiency relativistic backward wave oscillator based on cavity cooperation provided by the present invention;

[0028] Figure 7 It is a graph of the output power of the preferred embodiment of the high-efficiency relativistic backward wave oscillator based on cavity cooperation provided by the present invention varying with time;

[0029] Figure 8 It is a graph of the conversion efficiency varying with the drift cavity length L 12 when the preferred embodiment of the high-efficiency relativistic backward wave oscillator based on cavity cooperation provided by the present invention adopts a non-uniform slow-wave structure;

[0030] Figure 9The contrast diagram of fundamental wave currents when the preferred embodiments of the high-efficiency relativistic backward wave oscillator based on cavity matching provided by the present invention are respectively loaded with a single modulation cavity and a double modulation cavity;

[0031] Figure 10 The contrast diagram of electron power distributions when the preferred embodiments of the high-efficiency relativistic backward wave oscillator based on cavity matching provided by the present invention are respectively loaded with a single extraction cavity and a double extraction cavity;

[0032] Figure 11 The contrast diagram of output microwave powers when the preferred embodiments of the high-efficiency relativistic backward wave oscillator based on cavity matching provided by the present invention are respectively loaded with a single modulation cavity and a double modulation cavity;

[0033] Figure 12 The contrast diagram of output microwave powers when the preferred embodiments of the high-efficiency relativistic backward wave oscillator based on cavity matching provided by the present invention are respectively loaded with a single extraction cavity and a double extraction cavity. Detailed implementation manners

[0034] The accompanying drawings that form a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0035] The present invention is composed of a cathode base 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.

[0036] The cathode base 301 and the anode outer cylinder 303 are usually made of non-magnetic stainless steel materials. The cathode 302 can be made of high-hardness graphite or heat-resistant glass cloth-epoxy resin copper-clad laminate (FR-5) materials. The solenoid magnetic field 309 is wound with enameled copper wire or glass fiber-covered copper wire. The left end of the cathode base 301 is externally connected to the inner conductor of the pulsed power driver source, and the left end of the anode outer cylinder 303 is externally connected to the outer conductor of the pulsed power driver source.

[0037] When the present invention operates, the pre-stage pulsed power source is loaded onto the cathode base 301. The cathode 302 generates a ring-shaped high-current relativistic particle beam. The high-current relativistic particle beam is initially velocity-modulated in the double-gap modulation cavity 304 and further velocity-modulated by the first few blades of the non-uniform slow-wave structure 305. When the high-current relativistic particle beam passes through the drift cavity 306, it begins to turn into density modulation, forming the bunching of the electron beam. Then, when passing through the second section of the non-uniform slow-wave structure 305, the bunched electron beam interacts with the microwave field through beam-wave interaction, generating Cherenkov radiation and delivering energy to the microwave. When passing through the double-gap extraction cavity 307, the bunched electron beam is decelerated by the axial electric field, thereby generating concentrated transition radiation and further increasing the microwave output power.

[0038] This embodiment realizes a high-efficiency relativistic backward wave tube oscillator based on cavity cooperation with a working frequency of 7.80 GHz (corresponding to a microwave wavelength λ = 3.83 cm). The corresponding size design is as follows: R1 = 23 mm, R2 = 28 mm, R3 = 34 mm, R4 = 30.5 mm, R5 = 34 mm, R6 = 29 mm, R7 = 33.5 mm, R8 = 34 mm, R 10 = 35 mm, R 11 = 35.5 mm, R 12 = 35 mm, R 13 = 34.5 mm, R 14 = 37 mm, R 15 = 35 mm, L1 = 3 mm, L2 = 11.5 mm, L3 = 10.5 mm, L4 = 13 mm, L5 = 8 mm, L6 = 5 mm, L7 = 5 mm, L8 = 3 mm, L9 = 4.5 mm, L 10 = 4.5 mm, L 11 = 4 mm, L 12 = 13 mm, L 13 = 4 mm, L 14 = 4 mm, L 15 = 2.5 mm, L 16 = 3.5 mm, L 17 = 3 mm, L 18 = 3.5 mm, L 19 = 3 mm, L 20 = 3.5 mm, L 21 = 3.5 mm, L 22 = 5 mm, L 31 = 4 mm, L 32 = 4 mm, L 33 = 4 mm, L 34 = 4 mm, L 35 = 4 mm, L 36 = 5 mm, L 37 = 5 mm, L 38 = 4 mm, L 39 = 4 mm, L 40 = 3 mm, L 41 = 3 mm, L 42 = 3 mm, L 43 = 3 mm, L 44 = 9 mm, L 45 = 6.5 mm, L 46 = 3 mm.

[0039] In particle simulation, under the conditions of a diode voltage of 468 kV, a current of 5.7 kA, and a guiding magnetic field of 0.7 T, high-power microwaves with an output frequency of 7.80 GHz are generated. The output microwave power is 1.87 GW, and the conversion efficiency reaches 53%.

[0040] See Figure 4 , it can be seen that the reflection coefficient S of the double-gap reflection cavity used in the oscillator at the operating frequency of 7.80 GHz 11 is 0.997, which can effectively isolate the slow-wave structure region and the diode region, thereby improving the conversion efficiency.

[0041] See Figure 5 , it can be seen that the input electric power of the oscillator is 3.48 GW.

[0042] See Figure 6 , it can be seen that the frequency of the output microwave of the oscillator is 7.80 GHz, the spectrum is pure, and the frequency doubling is small.

[0043] See Figure 7 , it can be seen that the output microwave power of the oscillator is 1.84 GW.

[0044] See Figure 8 , it can be seen that when a 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 . As L 12 increases, the conversion efficiency first increases and then decreases. The optimal value of L 12 is 13 mm, and the conversion efficiency reaches the highest at this time, which is 53%.

[0045] See Figure 9 , it can be seen that compared with loading a single modulation cavity, after loading a double-gap modulation cavity, the overall modulation effect of the device on the electron beam is stronger, and the electron beam bunching near the extraction cavity is stronger, making the device have a higher beam-wave conversion efficiency.

[0046] See Figure 10 , it can be seen that compared with loading a single extraction cavity, after loading a double-gap extraction cavity, more beam current power can be converted into transition radiation, thereby improving the conversion efficiency.

[0047] See Figure 11 , it can be seen that compared with loading a single modulation cavity, the output microwave power is greatly increased when loading a double-gap modulation cavity, indicating that the modulation effect of the double-gap modulation cavity on the electron beam is stronger, thereby improving the beam-wave conversion efficiency.

[0048] See Figure 12 , it can be seen that compared with loading a single extraction cavity, the output microwave power is greatly increased 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 is 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 is L 32 , and the length of the right hypotenuse is 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 , and 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 , and 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 , and 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.

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