An electron bombardment resistant folded waveguide slow wave circuit, a traveling wave tube, and a method

Abstract

The embodiment of the application discloses an anti-electron bombardment folded waveguide slow wave circuit, a traveling wave tube and a method, which comprise a slow wave circuit with multi-periodicity formed by a plurality of upper grids and a plurality of lower grids staggered with each other; the slow wave circuit comprises a straight waveguide section, a curved waveguide connecting section and an electron beam channel; characterized in that the curved waveguide connecting section comprises an inner circular arc boundary C in , the inner circular arc boundary C in penetrates the electron beam channel in the wide edge direction of the straight waveguide section. The application provides a folded waveguide slow wave circuit structure, which eliminates the weak point of the conventional folded waveguide slow wave circuit in the high-efficiency slow wave circuit design, and greatly improves the anti-electron bombardment capability of the slow wave circuit.

Description

Technical Field

[0001] This invention relates to the field of microwave vacuum electronics technology. More specifically, it relates to a folded waveguide slow-wave circuit, traveling wave tube, and method resistant to electron bombardment. Background Technology

[0002] Terahertz traveling-wave tubes (TWTs) are a type of vacuum amplifier used to amplify the power of terahertz waves, playing a crucial role in the development of terahertz technology. Slow-wave circuits are where microwave signals exchange energy with the electron beam within the TWT. Currently, folded waveguide slow-wave circuits are suitable for circular beams in the terahertz band. These circuits feature an all-metal structure, strong heat dissipation, large bandwidth, simple and easy-to-fabricate input-output coupling structure, low high-frequency loss, and significant development potential.

[0003] A conventional folded waveguide slow-wave circuit is a pipe structure formed by bending the E-plane of a rectangular waveguide and arranging it periodically along the axial direction. Its basic structural unit vacuum model and main views are shown below. Figures 1a-1d In the slow-wave circuit structure, the central circular channel is the electron beam channel. The microwave signal propagates along a tortuous path within the waveguide, thereby reducing the phase velocity. The dimensional parameters of this slow-wave circuit structure are as follows: electron beam channel radius r; slow-wave circuit half-cycle length p (one cycle length 2p); straight waveguide section height h; slow-wave circuit wide side length a; straight waveguide section narrow side length b. In a conventional folded waveguide slow-wave circuit structure, the area enclosed by the outer and inner circular arc boundaries of the curved waveguide connecting section is denoted as 10; the area enclosed by the inner circular arc boundary of the curved waveguide connecting section and the boundary defined by the electron beam channel is denoted as 20, and this area is defined as an "island." The area where the electron beam channel is located is denoted as 30. As can be seen from the geometric parameters, in the terahertz band, the height h of the straight waveguide section is generally greater than the diameter 2r of the channel. The size of the "island" region in this structure mainly depends on the height h of the straight waveguide section, the half-cycle length p, and the narrow side length b of the waveguide in the slow wave circuit. As the operating frequency increases, due to the size coherence effect, the size of the "island" region 20 in the G-band is about 100 micrometers.

[0004] When using this basic folded waveguide slow-wave circuit structure for G-band high-efficiency circuit design, unlike broadband low-power circuit design, the size of the "island" region 20 inevitably shrinks significantly (e.g., a typical value decreases from 75µm to 40µm). This is because high-efficiency folded waveguide slow-wave circuit design requires increasing the coupling impedance of the slow-wave circuit, often by bringing the center frequency f0 closer to the lower cutoff frequency. This is mainly achieved by reducing the width of the slow-wave circuit's wide side length a. However, to ensure a reasonable operating voltage, the half-cycle length p of the slow-wave circuit must be very small. This combination leads to a rapid reduction in the size of the "island" region 20 in the slow-wave circuit; for example, in high-power designs, this value is typically only around 40µm. Such a small "island" region 20 becomes structurally fragile, and its high-frequency internal heat dissipation performance decreases significantly, posing a major challenge to thermal reliability.

[0005] On the other hand, the high-efficiency folded waveguide slow-wave circuit is limited by the performance of the external focusing magnetic field. During the actual operation of the traveling wave tube, the high-frequency field at the end of the slow-wave circuit is very strong, and the high-frequency radial field disturbs the electron beam quite violently, resulting in poor focusing. A large number of electrons give up a lot of energy, and their speed decreases significantly, causing the magnetic field parameters to increase, the rigidity of the electron beam to deteriorate, and the pulsation to increase. The high efficiency forms a high-density cluster, which increases the mutual repulsion of electrons. All of the above factors will cause high-energy electrons that could originally be stably transmitted in the electron beam channel (region 30) to hit the microstructure of the high-efficiency folded waveguide slow-wave circuit. The weakest part, namely the "island" region 20 enclosed by the inner arc of the folded waveguide and the channel boundary, will intercept a large amount of current, and the heat generated will burn out the region.

[0006] Taking the design of a high-efficiency slow-wave circuit using a conventional folded waveguide as an example, a 10W heat load was applied to the "island" region 20 enclosed by the inner arc of the folded waveguide and the channel boundary using relevant thermal simulation software. Simulation results show that the island temperature reached 996.38℃, which is close to the melting point of the material, indicating that the structure will burn out. Figure 2 As shown.

[0007] Considering both of the above factors, the "island" region 20 of the conventional folded waveguide slow-wave circuit in a high-efficiency interaction circuit is an extremely weak point. It will be destroyed by high-energy electrons under the high duty cycle operation of the traveling wave tube, causing the traveling wave tube to completely fail. Summary of the Invention

[0008] In view of the above problems, the first technical problem to be solved by the present invention is to provide a folded waveguide slow wave circuit that is resistant to electron bombardment, so as to greatly improve the resistance of the slow wave circuit to electron bombardment and meet the application of high-power traveling wave tubes.

[0009] The second technical problem to be solved by the present invention is to provide a traveling wave tube including the folded waveguide slow wave circuit described above.

[0010] The third technical problem to be solved by the present invention is to provide a design method for a folded waveguide slow-wave circuit resistant to electron bombardment, so as to obtain the folded waveguide slow-wave circuit as described above.

[0011] The fourth technical problem to be solved by the present invention is to provide a fabrication process for a folded waveguide slow-wave circuit resistant to electron bombardment, so as to obtain the folded waveguide slow-wave circuit as described above.

[0012] To solve the first technical problem mentioned above, the present invention adopts the following technical solution:

[0013] A folded waveguide slow-wave circuit resistant to electron bombardment includes a multi-periodic slow-wave circuit defined by multiple upper and lower gates arranged in an alternating pattern; the slow-wave circuit includes a connected straight waveguide section, a curved waveguide connecting section, and an electron beam channel; the curved waveguide connecting section includes an inner circular arc boundary C. in Inner circular arc boundary C in The electron beam channel runs through the wide side of the straight waveguide section.

[0014] Furthermore, a preferred embodiment is that, in the height direction of the straight waveguide section, the inner circular arc boundary C in There is a gap Δs between the boundary defined by the electron injection channel and the boundary.

[0015] Furthermore, in a preferred embodiment, the electron beam channel radius is r, the slow wave circuit half-cycle length is p, the straight waveguide section height is h, and the straight waveguide section narrow side length is b; the gap Δs ranges from [r-(pb) / 2]≤Δs≤(2r-p+b).

[0016] Furthermore, a preferred embodiment is that the inner circular arc boundary C in It can be a semicircular arc, a major arc, or a minor arc.

[0017] Furthermore, in a preferred embodiment, Δs is the arc boundary C within the curved waveguide connection section of the electron beam channel. in The vertical distance between endpoint Q and the outer boundary defined by the electron beam channel in the height direction of the straight waveguide section.

[0018] Furthermore, a preferred embodiment is that the curved waveguide connection segment has a non-semi-circular curved structure.

[0019] To solve the second technical problem mentioned above, the present invention adopts the following technical solution:

[0020] The present invention provides a traveling wave tube, which includes the folded waveguide slow wave circuit described above.

[0021] To solve the third technical problem mentioned above, the present invention adopts the following technical solution:

[0022] This invention provides a method for designing a folded waveguide slow-wave circuit resistant to electron bombardment, the method comprising:

[0023] An initial folded waveguide slow-wave circuit is designed according to requirements. This initial folded waveguide slow-wave circuit includes a connected straight waveguide section, a curved waveguide connection section, and an electron beam channel.

[0024] Using three-dimensional electromagnetic field simulation software, the inner arc boundary C of the curved waveguide connection section was lowered. in Within the boundaries defined by the electronic injection channel;

[0025] In the height direction of the straight waveguide section, the inner circular arc boundary C in A design gap Δs between the circuit and the boundary defined by the electron beam channel is used to improve the resistance of the slow-wave circuit to electron bombardment under the same thermal load conditions.

[0026] Furthermore, in a preferred embodiment, the electron beam channel radius r, the slow wave circuit half-cycle length p, the straight waveguide section height h, and the straight waveguide section narrow side length b are all specified. The value range of the gap Δs is: [r-(pb) / 2]≤Δs≤(2r-p+b).

[0027] To solve the fourth technical problem mentioned above, the present invention adopts the following technical solution:

[0028] This invention provides a fabrication process for a folded waveguide slow-wave circuit resistant to electron bombardment, comprising the following steps:

[0029] On a structural half, a first slow-wave circuit channel and a first electron beam channel are formed by machining a cross-sectional plane, which are defined by a plurality of first upper gates and a plurality of first lower gates that are distributed in an alternating manner.

[0030] On another structural half, a second slow-wave circuit channel and a second electron beam channel are formed by machining a cross-sectional plane, which are defined by a plurality of second upper half gates and a plurality of second lower half gates that are staggered with each other.

[0031] Two structural half-sections are aligned and interlocked, forming a folded waveguide slow-wave circuit through pressure diffusion welding.

[0032] The area enclosed by the first slow wave circuit channel and the second slow wave circuit channel forms a slow wave circuit of folded waveguide slow wave circuit.

[0033] The region enclosed by the first electron beam channel slot and the second electron beam channel slot forms the electron beam channel of the folded waveguide slow wave circuit.

[0034] Multiple first upper gate bodies and multiple second upper half gate bodies form the upper gate body structure of the folded waveguide slow wave circuit; multiple first lower gate bodies and multiple second lower half gate bodies form the upper and lower gate body structures of the folded waveguide slow wave circuit.

[0035] The beneficial effects of this invention are as follows:

[0036] While maintaining the electrical performance of conventional folded waveguide slow-wave circuits and without increasing structural complexity, this invention provides a folded waveguide slow-wave circuit structure resistant to electron bombardment. All of these measures aim to eliminate the weaknesses of conventional folded waveguide slow-wave circuits in high-efficiency slow-wave circuit design, significantly improve the slow-wave circuit's resistance to electron bombardment, increase the efficiency of traveling wave tubes, and meet the application requirements of high-power traveling wave tubes.

[0037] Based on the improved resistance to electron bombardment by the slow-wave circuit, the pressure on the focusing system can be reduced. This enables the traveling wave tube using the slow-wave circuit to operate in a high duty cycle or even continuous wave mode, greatly expanding the range of duty cycles in which the traveling wave tube can operate normally. Attached Figure Description

[0038] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0039] Figure 1a This shows a front view of the structure of a conventional folded waveguide slow wave circuit for one cycle.

[0040] Figure 1b The right view shows the structure of one cycle of a conventional folded waveguide slow wave circuit.

[0041] Figure 1c A top view of the structure of a conventional folded waveguide slow wave circuit for one cycle is shown.

[0042] Figure 1d This diagram shows a three-dimensional schematic of one cycle of a conventional folded waveguide slow wave circuit.

[0043] Figure 2 The temperature characteristics of the island region of a conventional folded waveguide slow wave circuit under concentrated electron bombardment are shown.

[0044] Figure 3a This diagram shows a front view of the structure of one cycle of the folded waveguide slow wave circuit provided by the present invention.

[0045] Figure 3b The diagram shows a right view of the structure of one cycle of the folded waveguide slow wave circuit provided by the present invention.

[0046] Figure 3c The diagram shows a top view of one cycle of the folded waveguide slow wave circuit provided by the present invention.

[0047] Figure 3dThis diagram shows a three-dimensional schematic of one cycle of the folded waveguide slow wave circuit provided by the present invention.

[0048] Figure 4 The diagram shows a front view of the structure of the folded waveguide slow wave circuit provided by the present invention, covering two cycles.

[0049] Figure 5 The diagram shows the temperature characteristics of the folded waveguide slow-wave circuit provided by the present invention under concentrated electron bombardment.

[0050] Figure 6 The diagram shows a comparison of the dispersion characteristics of the folded waveguide slow-wave circuit provided by this invention and a conventional folded waveguide slow-wave circuit.

[0051] Figure 7 The diagram shows a comparison of the loss characteristics of the folded waveguide slow-wave circuit provided by the present invention and a conventional folded waveguide slow-wave circuit.

[0052] Figure 8 The diagram shows a comparison of the coupling impedance characteristics between the folded waveguide slow wave circuit provided by this invention and a conventional folded waveguide slow wave circuit.

[0053] Figure 9 The diagram shows a structural half-body of a folded waveguide slow wave circuit fabrication process provided by the invention. Detailed Implementation

[0054] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0055] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0056] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0057] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0058] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0059] Folded waveguide slow-wave circuits are mainly used in terahertz traveling-wave tube (TWT) type vacuum amplifiers to amplify the power of terahertz waves, which is of great significance to the development of terahertz technology. As the site of energy exchange between microwave signals and electron beams in the TWT, the slow-wave circuit needs to have strong heat dissipation capabilities, large bandwidth, simple and easy-to-fabricate input-output coupling structure, and low high-frequency loss. Currently, the "island" region of conventional folded waveguide slow-wave circuits has insufficient resistance to electron bombardment under the high duty cycle operation of the TWT, making it susceptible to damage by high-energy electrons and causing complete failure of the TWT.

[0060] In response to the shortcomings of existing technologies, this invention, in one aspect, firstly provides a folded waveguide slow-wave circuit resistant to electron bombardment, such as... Figures 3a to 3b and combined Figure 4 As shown, specifically, the folded waveguide slow-wave circuit provided by the present invention includes a multi-periodic slow-wave circuit defined by multiple upper gates and multiple lower gates distributed in an alternating manner; the slow-wave circuit includes a connected straight waveguide section 100, a curved waveguide connecting section 200, and an electron beam channel 300. As shown, the radius of the electron beam channel 300 is r, the half-cycle length of the slow-wave circuit is p, the length of one cycle is 2p, the height of the straight waveguide section 100 is h, and the narrow side length of the straight waveguide section 100 is b. The curved waveguide connecting section 200 in the present invention includes an inner circular arc boundary C. in Inner circular arc boundary C in The electron beam channel 300 extends through the wide side of the straight waveguide section 100.

[0061] In this invention, the inner arc boundary C of the curved waveguide connection section 200 of the slow wave circuit is... in Move down to within the boundary 301 defined by the electron injection channel 300, refer to Figure 3a As shown, this completely eliminates the "island" region 20 in conventional folded waveguide slow wave circuits.

[0062] Using three-dimensional electromagnetic field simulation software, the performance of the slow-wave circuit provided by this invention and the conventional folded waveguide slow-wave circuit were compared when designing narrowband high-efficiency interaction circuits. For example... Figure 6 As shown, Figure 6 This diagram shows a comparison of the dispersion characteristics of the folded waveguide slow-wave circuit provided by this invention and a conventional folded waveguide slow-wave circuit, characterizing the operating voltage and bandwidth of the traveling wave tube (TWT). At the center frequency, the slow-wave circuit structure provided by this invention has the same normalized phase velocity as the conventional folded waveguide slow-wave circuit structure, indicating that the TWT using the slow-wave circuit structure provided by this invention has the same voltage as the TWT using the conventional folded waveguide slow-wave circuit structure. The dispersion flatness is essentially the same within the frequency band, indicating that the TWT using the slow-wave circuit structure provided by this invention has the same bandwidth as the TWT using the conventional folded waveguide slow-wave circuit structure.

[0063] Figure 7 The diagram shows a comparison of the loss characteristics of the folded waveguide slow wave circuit provided by the present invention and the conventional folded waveguide slow wave circuit. The two slow wave circuits are basically consistent within the frequency band, indicating that the slow wave circuit structure provided by the present invention does not introduce additional losses compared with the conventional folded waveguide slow wave circuit structure. Figure 8 The diagram shows a comparison of the coupling impedance characteristics of the folded waveguide slow-wave circuit provided by this invention and the conventional folded waveguide slow-wave circuit. The folded waveguide slow-wave circuit structure provided by this invention improves the frequency band performance by 10% compared to the conventional folded waveguide slow-wave circuit structure. This indicates that the folded waveguide slow-wave circuit provided by this invention has a stronger interaction strength than the conventional folded waveguide slow-wave circuit, suggesting that the traveling wave tube using the folded waveguide slow-wave circuit provided by this invention has greater output power, and the efficiency of the traveling wave tube is effectively improved and guaranteed.

[0064] Furthermore, refer to Figure 5 As shown, Figure 5 The diagram shows the temperature characteristics of the folded waveguide slow-wave circuit provided by this invention under concentrated electron bombardment. Thermal analysis software was used to simulate the temperature distribution of the folded waveguide slow-wave circuit provided by this invention under a 10W heat load. The simulation results show that the temperature distribution of the folded waveguide slow-wave circuit provided by this invention is within the inner arc boundary C of the 200mm curved waveguide connection section of the slow-wave circuit. in After moving down to within the boundary 301 defined by the electron beam channel 300, the inner arc boundary C of the curved waveguide connection section 200 in Compared with the "island" region 20 in the conventional folded waveguide slow wave circuit structure, the highest temperature at this location can be reduced from 996.3℃ in the conventional structure to 524.95℃.

[0065] In summary, the folded waveguide slow-wave circuit provided by this invention is applicable to high-power narrowband traveling wave tubes. Compared with conventional folded waveguide slow-wave circuits, while maintaining the same dispersion and loss characteristics, it directly eliminates the weak points of conventional folded waveguides and possesses greater output power potential. Under the same thermal load conditions, the maximum temperature of the oxygen-free copper surface in the electron bombardment-resistant narrowband high-efficiency folded waveguide slow-wave circuit is reduced from 996.3℃ to 524.95℃, which is nearly 50% lower than that of conventional slow-wave circuits, significantly enhancing its resistance to electron bombardment while remaining compatible with existing precision machining processes.

[0066] In one embodiment, the boundary 301 defined by the electron injection channel 300 and the inner arc boundary C inThe intersection forms a junction region 400. The closer the junction region 400 is to the center of the electron beam channel 300 in the height h direction of the straight waveguide section, the stronger the overall anti-bombardment capability of the folded waveguide slow-wave circuit. However, its electrical characteristics will be negatively affected, which in turn affects the performance of the high-frequency circuit itself. In view of this, in the design of a high-efficiency folded waveguide slow-wave circuit resistant to electron bombardment, in the height direction of the straight waveguide section, the inner arc boundary C in There is a gap Δs between the electron beam channel 300 and the boundary 301 defined by the electron beam channel 300. The value range of the gap Δs is: [r-(pb) / 2]≤Δs≤(2r-p+b), which can improve the bombardment resistance of the structure itself while keeping the electrical characteristics basically unchanged within the frequency band.

[0067] In one embodiment, the curved waveguide connection segment has a non-semi-circular curved structure. Optionally, the inner circular arc boundary C in It can be a semicircular arc, a major arc, or a minor arc. In a further preferred embodiment, the inner circular arc boundary C in For a minor arc, when the inner arc boundary C in When the structure is a minor arc, the internal cavity volume of the curved waveguide connection section can be effectively increased, the field strength distribution inside the folded waveguide can be changed, the field strength near the electron beam channel can be increased, the coupling impedance amplitude of the slow wave circuit can be effectively increased, and the power and efficiency of the device can be effectively improved.

[0068] In this invention, Δs is the arc boundary C within the curved waveguide connection section of the electron beam channel. in The vertical distance between endpoint Q and the outer boundary defined by the electron beam channel in the height direction of the straight waveguide section.

[0069] According to another aspect of the present invention, a traveling wave tube (TWT) is provided, comprising the folded waveguide slow-wave circuit described above. Under the premise of consistent dispersion and loss characteristics, the slow-wave circuit structure of the present invention directly eliminates the weak points of conventional folded waveguide slow-wave circuits. This allows the TWT using the slow-wave circuit provided by the present invention to possess greater output power potential, reduces the pressure on the focusing system, and enables the TWT using this slow-wave circuit to achieve high duty cycle or even continuous wave operation, greatly expanding the duty cycle range in which the TWT can operate normally.

[0070] According to another aspect of the present invention, there is also a design method for a folded waveguide slow-wave circuit resistant to electron bombardment, used to improve the electron bombardment resistance performance of the slow-wave circuit, the method comprising:

[0071] An initial folded waveguide slow-wave circuit is designed as needed. This initial folded waveguide slow-wave circuit includes a connected straight waveguide section 100, a bent waveguide connection section 200, and an electron beam channel 300.

[0072] Using three-dimensional electromagnetic field simulation software, the inner arc boundary C of the curved waveguide connection section was lowered by 200 mm. in Within the boundary 301 defined by the electron beam channel 300, that is, structurally speaking, the inner arc boundary C of the curved waveguide connection section 200. in The electron beam channel 300 extends through the wide side of the straight waveguide section 100.

[0073] In the height direction of the straight waveguide section 100, the inner circular arc boundary C in A design gap Δs is made between the slow-wave circuit and the boundary 301 defined by the electron injection channel 300 to improve the resistance to electron bombardment under the same thermal load conditions.

[0074] In machine tool processing, based on the existing conventional folded waveguide slow wave circuit, the inner arc boundary C of the curved waveguide connection section is... in By completely eliminating the "island" region in conventional folded waveguide slow wave circuits within the boundary defined by the electron beam channel, the folded waveguide slow wave circuit structure resistant to electron bombardment provided by this invention can be formed.

[0075] Furthermore, based on the initial folded waveguide slow-wave circuit design structure size characteristics, the matching performance of the slow-wave circuit is optimized using the electron beam channel radius r, the slow-wave circuit half-cycle length p, the straight waveguide section height h, and the straight waveguide section narrow side length b. The value range of the gap Δs is: [r-(pb) / 2]≤Δs≤(2r-p+b). In one example, if the gap Δs<[r-(pb) / 2], the bombardment resistance of the slow-wave circuit will be severely reduced, and the duty cycle of the traveling wave tube will be worse than that of a traveling wave tube using a conventional slow-wave circuit. If the gap Δs>(2r-p+b), the electrical characteristics of the slow-wave circuit will be severely affected, resulting in the traveling wave tube output power and power bandwidth being worse than those of a traveling wave tube using a conventional slow-wave circuit.

[0076] According to another aspect of the invention, referring to Figure 9 As shown, the present invention also provides a fabrication process for a folded waveguide slow-wave circuit resistant to electron bombardment. Both processes are based on conventional folded waveguide slow-wave circuit fabrication processes, and obtain the folded waveguide slow-wave circuit provided by the present invention without increasing process complexity or precision. The process includes the following steps:

[0077] S1. A first slow wave circuit channel 504 and a first electron beam channel 505 with multiple periods are formed by a plurality of first upper gate bodies 502 and a plurality of first lower gate bodies 503 that are distributed intermittently on a cross-sectional plane 501 on a structural half body 500.

[0078] S2. On another structural half, a second slow-wave circuit channel and a second electron beam channel are formed by machining a cross-sectional plane, which are defined by a plurality of second upper half gates and a plurality of second lower half gates that are staggered with each other.

[0079] S3. The two structural half-body cross-sections are opposite to each other and interlocked, forming a folded waveguide slow-wave circuit through pressure diffusion welding. It should be noted that the area enclosed by the first slow-wave circuit channel 504 and the second slow-wave circuit channel forms the slow-wave circuit of the folded waveguide slow-wave circuit, and the area enclosed by the first electron beam channel channel 505 and the second electron beam channel channel forms the electron beam channel of the folded waveguide slow-wave circuit.

[0080] Multiple first upper gate bodies 502 and multiple second upper half gate bodies form the upper gate body structure of the folded waveguide slow wave circuit, and multiple first lower gate bodies 503 and multiple second lower half gate bodies form the upper and lower gate body structures of the folded waveguide slow wave circuit.

[0081] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A folded waveguide slow-wave circuit resistant to electron bombardment, comprising a multi-periodic slow-wave circuit defined by a plurality of upper gates and a plurality of lower gates arranged in an alternating manner; the slow-wave circuit includes a connected straight waveguide section, a curved waveguide connecting section, and an electron beam channel; characterized in that, The curved waveguide connection segment includes an inner circular arc boundary C. in Inner circular arc boundary C in The electron beam channel extends through the wide side of the straight waveguide section; In the height direction of the straight waveguide section, the inner circular arc boundary C in There is a gap Δs between the electron injection channel and the boundary defined by the channel. The electron beam channel radius is r, the slow wave circuit half-cycle length is p, the straight waveguide section height is h, and the straight waveguide section narrow side length is b; the gap Δs ranges from [r-(pb) / 2] to Δs ≤ (2r-p+b). Δs is the arc boundary C within the curved waveguide connection section of the electron beam channel. in The vertical distance between endpoint Q and the outer boundary defined by the electron beam channel in the height direction of the straight waveguide section.

2. The slow-wave circuit according to claim 1, characterized in that, The inner circular arc boundary C in It can be a semicircular arc, a major arc, or a minor arc.

3. The slow-wave circuit according to claim 1, characterized in that, The curved waveguide connection section has a non-semi-circular curved structure.

4. A traveling wave tube, characterized in that, The traveling wave tube includes the folded waveguide slow wave circuit according to claim 1.

5. A method for designing a folded waveguide slow-wave circuit resistant to electron bombardment, characterized in that, The method includes: An initial folded waveguide slow-wave circuit is designed according to requirements. This initial folded waveguide slow-wave circuit includes a connected straight waveguide section, a bent waveguide connection section, and an electron beam channel. Using three-dimensional electromagnetic field simulation software, the inner arc boundary C of the curved waveguide connection section was lowered. in Within the boundaries defined by the electronic injection channel; In the height direction of the straight waveguide section, the inner circular arc boundary C in A design gap Δs between the circuit and the boundary defined by the electron beam channel is used to improve the resistance of the slow-wave circuit to electron bombardment under the same thermal load conditions. The electron beam channel radius r, the slow wave circuit half-cycle length p, the straight waveguide section height h, and the straight waveguide section narrow side length b; the gap Δs has the following range: [r-(pb) / 2]≤Δs≤(2r-p+b). Δs is the arc boundary C within the curved waveguide connection section of the electron beam channel. in The vertical distance between endpoint Q and the outer boundary defined by the electron beam channel in the height direction of the straight waveguide section.

Images