Elliptical three-stage voltage reduction collector
By designing an elliptical three-stage step-down collector structure, the problems of electrode heating, disordered electron trajectories, and insufficient insulation in multi-stage step-down collector designs are solved, achieving efficient heat dissipation and improved stability, and making it suitable for high-frequency strip-beam traveling wave tubes.
Patent Information
- Application Number
- CN202510213379.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-26
- Publication Date
- 2026-03-03
- Estimated Expiration
- 2045-02-26
AI Technical Summary
Existing multi-stage step-down collector designs in high-power strip beam traveling wave tubes suffer from severe electrode heating, disordered electron trajectories, high risk of electric field breakdown, and insufficient insulation, leading to a decline in device performance.
It adopts an elliptical three-stage step-down collector structure, including a metal outer cylinder with heat dissipation fins, a ceramic inner cylinder, and a multi-stage collector assembly. It is designed in an elliptical shape and has smooth curved grooves and conical structures inside. Combined with water cooling, it optimizes electron trajectory and electric field distribution.
It effectively reduces power dissipation density, decreases secondary electron backflow rate, improves heat dissipation efficiency, and ensures device stability and insulation, making it suitable for high-frequency applications.
Smart Images
Figure CN120126984B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of vacuum electronics technology, specifically relating to an elliptical three-stage step-down collector structure. Background Technology
[0002] A strip-beam traveling wave tube (TBWT) is a vacuum amplification device that operates based on the electron cyclotron pulsation instability mechanism. Compared to other vacuum electronic devices, it features high frequency, wide bandwidth, high power, and high gain, making it a promising candidate for applications in electronic warfare, radar imaging, missile guidance, and satellite communications. Due to the development of military equipment and various civilian sectors, the demand for high power and high frequency in vacuum electronic devices is increasing, leading to growing attention and research on TWDTs.
[0003] A traveling wave tube (TWT) consists of five parts: an electron gun, an input / output energy coupling structure, a slow-wave structure, a focusing system, and a collector. The electron beam emitted from the electron gun enters the coupling structure, interacts with electromagnetic waves, forms a cluster, and is eventually collected by the collector. Traditional pencil-shaped electron beams, as they evolve towards higher frequencies, suffer from size convergence effects, resulting in increasingly smaller beams and greater space charge forces, making focusing more difficult. This makes increasing output power by increasing current at high frequencies extremely challenging. In contrast, strip-shaped electron beams, with their larger aspect ratio, allow for increased lateral dimensions to reduce current density as current increases, thereby minimizing the influence of space charge forces and reducing the difficulty of current focusing. Furthermore, the flat shape of strip-shaped electron beams is more suitable for planar slow-wave structures, facilitating device integration and miniaturization. Therefore, strip-shaped vacuum electronic devices are receiving increasing attention.
[0004] Based on the working principle of a strip-beam traveling wave tube (TWT), there are generally two ways to improve the efficiency of a TWT device: improving the interaction section to increase the interaction efficiency and recovering electron energy. However, due to the limitations of the beam-wave interaction principle, it is very difficult to further improve the interaction efficiency of a TWT. Therefore, using a multi-stage step-down collector to recover the electron beam after interaction is a very common method to improve the efficiency of the TWT.
[0005] Existing multi-stage step-down collector designs face the following challenges:
[0006] 1) Since the step-down collector cannot recover 100% of the remaining electron energy, the remaining electron kinetic energy will be converted into heat energy inside the collector. In high-power strip beam traveling wave tubes, the electrodes inside the collector generate a lot of heat. When the heat dissipation capacity is insufficient, it may lead to the melting of the device.
[0007] 2) After the beam-wave interaction occurs, the distribution of the strip electron beam is more disordered than that of the traditional pencil electron beam. At the same time, due to the influence of the complex electric field inside the step-down collector, the electron trajectory inside the collector is more disordered. Compared with the pencil electron beam, it lacks axisymmetry, making it more difficult to design a multi-stage step-down collector that can absorb electron energy more uniformly.
[0008] 3) The breakdown of the electric field inside the multi-stage step-down collector needs to be taken into account. At the same time, for insulation, ceramic is usually used as the outer cylinder. This means that the temperature cannot be too high, otherwise it will cause the ceramic to leak and affect the performance of the whole tube. Summary of the Invention
[0009] To address the problem of uneven electron collision power distribution in existing methods, this invention proposes an elliptical three-stage step-down collector. This collector can reduce the maximum power dissipation density and the backflow rate of secondary electrons to a certain extent, while also achieving better heat dissipation.
[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0011] An elliptical three-stage step-down collector electrode, characterized in that it comprises: an elliptical metal outer cylinder with heat dissipation fins;
[0012] An elliptical ceramic inner cylinder is disposed inside the outer metal cylinder;
[0013] The first-stage collecting electrode assembly, the second-stage collecting electrode assembly, and the third-stage collecting electrode assembly are located inside the ceramic inner cylinder and distributed sequentially along the axial direction.
[0014] The first-stage collector assembly includes: a first elliptical cylinder, a first input end face disposed at the input end of the first elliptical cylinder and protruding inward, and a first output end face disposed at the output end of the first elliptical cylinder and protruding outward, the three together forming a first collecting cavity; wherein, a first input channel is disposed in the middle of the first input end face for injecting a strip-shaped electron beam; a smooth curved groove is disposed on the outer side of the first input channel; and a first output port is disposed in the middle of the first output end face;
[0015] The second-stage collecting electrode assembly includes: a second elliptical cylinder, a second input end face disposed at the input end of the second elliptical cylinder and protruding inward, and a second output end face disposed at the output end of the second elliptical cylinder and protruding outward, the three together forming a second collecting cavity; wherein, a second input channel is disposed in the middle of the second input end face, and the input end of the second input channel extends into the first output port; a second output port is disposed in the middle of the second output end face;
[0016] The third-stage collector assembly includes: a third elliptical cylinder, a third input end face disposed at the input end of the third elliptical cylinder and protruding outward, and a third output end face disposed at the output end of the third elliptical cylinder, which together form a second collecting cavity; wherein, a third input channel is disposed in the middle of the third input end face, and the input end of the third input channel extends into the second output port; along the electron beam input direction, the second collecting cavity first smoothly transitions to an elliptical inner wall from the output end of the third input channel, then gradually transitions to a circular inner wall through a transition section, and finally connects to a hemispherical inner wall; a conical structure protruding in the electron input direction is disposed in the middle of the hemispherical inner wall.
[0017] Furthermore, the ceramic inner cylinder is divided into a first ceramic inner cylinder section and a second ceramic inner cylinder section, and a gap is provided between the two sections; the first-stage collecting electrode assembly and the second-stage collecting electrode assembly are located in the first ceramic inner cylinder section, and the third-stage collecting electrode assembly is located in the second ceramic inner cylinder section;
[0018] Furthermore, a ring-shaped structure protrudes from one end of the second ceramic inner cylinder section near the first ceramic inner cylinder section toward the central axis; this is used to isolate the electric field between the second collector assembly and the third collector assembly.
[0019] Furthermore, the first input channel is cuboid in shape, and its aperture matches the strip electron beam; the second and third input channels are frustum in shape, and any cross-section perpendicular to the axis is a rectangle with the same aspect ratio, and the output end face aperture of the second input channel is smaller than the input end face aperture of the third input channel; the opening shape of the first and second output ports is rectangular.
[0020] Furthermore, the heat dissipation fins are evenly distributed along the circumference and have the same length as the metal outer cylinder; at the same time, cooling water is used to dissipate heat from the heat dissipation fins.
[0021] Furthermore, the apex of the conical structure is rounded to prevent sparking at the tip.
[0022] The principle and beneficial effects of this invention:
[0023] 1) The electron beam after the interaction is not uniform in terms of position and velocity distribution in the angular direction. By adopting an elliptical collecting electrode structure, the remaining energy distribution can be more uniform after the collecting electrode has collected all the electrons, reducing the power dissipation density and thus reducing the temperature while controlling the overall volume.
[0024] 2) The present invention has grooves around the electron input channel of the first-stage collector assembly to capture electrons that flow back from the second-stage and third-stage collector assemblies to the vicinity of the input channel of the first-stage collector assembly, thereby increasing the collision area of electrons and reducing the power dissipation density and the proportion of electrons flowing back out of the collector.
[0025] 3) The present invention modifies the front-end transition structure of the first-stage collector assembly and the second-stage collector assembly to be inclined with a negative slope (i.e. bulging in the direction of electron transport), so that a groove is formed between the input channel and the elliptical collector cavity, so as to intercept the generated secondary electrons and thereby reduce the electron backflow rate.
[0026] 4) This invention uses insulating ceramic to isolate the collector voltage, adds a metal outer cylinder and heat dissipation fins to the insulating ceramic layer, and uses water cooling with a faster flow rate instead of oil cooling to reduce the temperature of the collector during operation.
[0027] 5) The present invention adopts a hemispherical cavity at the tail end of the third-stage collector assembly, which increases the contact area between electrons and the collector and reduces the power dissipation density; at the same time, a conical structure is set at the bottom of the hemispherical cavity, which further increases the contact area between electrons and the collector and reduces the generation of secondary electrons. Attached Figure Description
[0028] To gain a more complete understanding of this disclosure and its advantages, reference will now be made to the following description taken in conjunction with the accompanying drawings, wherein:
[0029] Figure 1 A perspective view of a multi-stage step-down collector electrode according to an embodiment of the present disclosure is shown schematically.
[0030] Figure 2 A perspective view of the outer cylinder according to an embodiment of the present disclosure is shown schematically.
[0031] Figure 3 A perspective view of the inner cylinder according to an embodiment of the present disclosure is shown schematically.
[0032] Figure 4 A perspective view of the first stage collector assembly of a multi-stage step-down collector according to an embodiment of the present disclosure is shown schematically.
[0033] Figure 5 A perspective view of a second-stage collector assembly of a multi-stage step-down collector according to an embodiment of the present disclosure is shown schematically.
[0034] Figure 6 A perspective view of a third-stage collector assembly of a multi-stage step-down collector according to an embodiment of the present disclosure is shown schematically.
[0035] Figure 7 This is a schematic diagram of a typical strip electron beam.
[0036] Explanation of reference numerals: 1. Metal outer cylinder; 2-1. First ceramic inner cylinder section; 2-2. Second ceramic inner cylinder section; 3. Heat dissipation fins; 4. First-stage collector assembly; 4-1. First input channel; 4-2. First input end face; 4-3. First output end face; 4-4. Smooth curved groove; 4-5. First output port; 5. Second-stage collector assembly; 5-1. Second input channel; 5-2. Second input end face; 5-3. Second output end face; 5-4. Second output end face; 6. Third-stage collector assembly; 6-1. Third input channel; 6-2. Third input end face; 6-3. Gradually transitioning to a circular inner wall; 6-4. Hemispherical inner wall; 6-5. Conical structure. Detailed Implementation
[0037] The invention will be further described in detail below with reference to the accompanying drawings, using a Ka-band elliptical multi-stage step-down collector as an example:
[0038] This embodiment describes an elliptical three-stage step-down collector applied to the Ka-band, such as... Figure 1 As shown, the structure includes: an elliptical metal outer cylinder with heat dissipation fins; the metal outer cylinder has a thickness of 0.2 mm, a length of 64.5 mm, a major axis length a of 28 mm, and a minor axis length b of 23.6 mm on the inner wall of the metal outer cylinder; the heat dissipation fins are evenly distributed along the circumference, with a height of 3 mm, a width of 2.28 mm, and a length the same as the length of the metal outer cylinder; simultaneously, cooling water is used to dissipate heat from the heat dissipation fins.
[0039] An elliptical ceramic inner cylinder is disposed within the outer metal cylinder; such as Figure 2 As shown, the ceramic inner cylinder is divided into a first ceramic inner cylinder section and a second ceramic inner cylinder section, with a 1mm gap between the two sections; the end of the second ceramic inner cylinder section near the first ceramic inner cylinder section has a ring structure protruding towards the central axis to isolate the electric field between the second collector electrode assembly and the third collector electrode assembly. The ring structure has a thickness of 2mm along the axial direction, an internal major axis radius of 22mm, and a minor axis radius of 17.6mm.
[0040] The first ceramic inner cylinder section is equipped with a first-stage collecting electrode assembly and a second-stage collecting electrode assembly, and the second ceramic inner cylinder section is equipped with a third-stage collecting electrode assembly. The central axes of the three collecting electrode assemblies coincide with the axis of the ceramic inner cylinder, and there is a certain gap between the three collecting electrode assemblies (they do not contact each other). Different voltages are applied during operation.
[0041] like Figure 3As shown, the first-stage collector assembly includes: a first elliptical cylinder with a major axis of 22mm, a minor axis of 17.6mm, and a length of 2mm; a first input end face disposed at the input end of the first elliptical cylinder and protruding inward (protrusion height of 2mm); and a first output end face disposed at the output end of the first elliptical cylinder and protruding outward (protrusion height of 7.2mm), the three together forming a first collecting cavity; wherein, a first input channel with a length of 5.2mm and a width of 2mm is disposed in the middle of the first input end face for injecting a strip-shaped electron beam, such as... Figure 7 As shown, the electron distribution at the inlet of the multi-stage step-down collector in the strip-shaped injection system is a twisted rectangle, 4 mm long and 0.5 mm wide. A smooth curved groove with a maximum depth of 4 mm is provided on the outer side of the first input channel. A first output port with a length of 14 mm and a width of 13 mm is provided in the middle of the first output end face. The first input end face is designed as an inwardly smooth protrusion, which works in conjunction with the smooth curved groove around the electron injection channel to capture secondary electrons generated by collisions of electrons flowing back into the region, thereby reducing backflow. The first output end face is designed as an outwardly smooth protrusion, which works in conjunction with the end output port to reduce the influence of the electric field of the second collector assembly, preventing electrons from concentrating at the front end of the collecting cavity, making the electron distribution more uniform within the first collecting cavity, and simultaneously preventing electrons from moving radially as much as possible, thus maximizing the recovery of electron energy. The principle of the second collector assembly is the same as that of the first collector assembly.
[0042] like Figure 4 As shown, the second-stage collecting electrode assembly includes: a second elliptical cylinder with a major axis of 22mm, a minor axis of 17.6mm, and a length of 8.68mm; a second input end face disposed at the input end of the second elliptical cylinder and smoothly protruding inward (protrusion height of 2mm); and a second output end face disposed at the output end of the second elliptical cylinder and smoothly protruding outward (protrusion height of 6mm). The three together form a second collecting cavity. Among them, a second input channel with a length of 3mm is disposed in the middle of the second input end face. The second input channel is cuboid in shape with dimensions of 10mm*9mm, and the input end of the second input channel extends into the first output port. A second output port with a length of 21mm and a width of 21mm is disposed in the middle of the second output end face.
[0043] like Figure 5As shown, the third-stage collecting electrode assembly includes: a third elliptical cylinder, a third input end face disposed at the input end of the third elliptical cylinder and protruding outward, and a third output end face disposed at the output end of the third elliptical cylinder, the three of which together form a second collecting cavity; wherein, a third input channel with a length of 3mm is disposed in the middle of the third input end face, the third input channel is cuboid in shape with dimensions of 14mm*14mm, and the input end of the third input channel extends into the second output port; along the electron beam input direction, the second collecting cavity first smoothly transitions to an elliptical inner wall from the output end of the third input channel (the length of this transition section is 4mm, the major axis of the elliptical inner wall is 22mm, and the minor axis is 17.6mm), and then passes through a section A transition section with a length of 8.4 mm gradually transitions to a circular inner wall with a radius of 17.6 mm, and finally connects to a hemispherical inner wall with a radius of 17.6 mm. The middle of the hemispherical inner wall is provided with a conical structure protruding in the electron input direction. The height of the conical structure is 35 mm, the bottom radius is 8.5 mm, and the apex corner of the conical structure is rounded to prevent arcing at the tip. The hemispherical inner wall can increase the electron collection area, reduce the power dissipation density, and thus reduce the temperature. The conical structure can further increase the electron collection area and reduce the generation of secondary electrons. Simultaneously, it forms a radial electric field with the second-stage collector assembly, increasing the radial force on the electron beam, thereby allowing the electron beam to diffuse faster radially and achieve a more uniform power dissipation density.
Claims
1. An elliptical three-stage voltage-dropping collector, characterized in that, include: An oval-shaped metal outer cylinder with heat dissipation fins; An elliptical ceramic inner cylinder is disposed inside the outer metal cylinder; The first-stage collecting electrode assembly, the second-stage collecting electrode assembly, and the third-stage collecting electrode assembly are located inside the ceramic inner cylinder and distributed sequentially along the axial direction. The first-stage collector assembly includes: a first elliptical cylinder, a first input end face disposed at the input end of the first elliptical cylinder and protruding inward, and a first output end face disposed at the output end of the first elliptical cylinder and protruding outward, the three together forming a first collecting cavity; wherein, a first input channel is disposed in the middle of the first input end face for injecting a strip-shaped electron beam; a smooth curved groove is disposed on the outer side of the first input channel; and a first output port is disposed in the middle of the first output end face; The second-stage collecting electrode assembly includes: a second elliptical cylinder, a second input end face disposed at the input end of the second elliptical cylinder and protruding inward, and a second output end face disposed at the output end of the second elliptical cylinder and protruding outward, the three together forming a second collecting cavity; wherein, a second input channel is disposed in the middle of the second input end face, and the input end of the second input channel extends into the first output port; a second output port is disposed in the middle of the second output end face; The third-stage collector assembly includes: a third elliptical cylinder, a third input end face disposed at the input end of the third elliptical cylinder and protruding outward, and a third output end face disposed at the output end of the third elliptical cylinder, which together form a second collecting cavity; wherein, a third input channel is disposed in the middle of the third input end face, and the input end of the third input channel extends into the second output port; along the electron beam input direction, the second collecting cavity first smoothly transitions to an elliptical inner wall from the output end of the third input channel, then gradually transitions to a circular inner wall through a transition section, and finally connects to a hemispherical inner wall; a conical structure protruding in the electron input direction is disposed in the middle of the hemispherical inner wall.
2. The elliptical three-stage step-down collector electrode as described in claim 1, characterized in that, The ceramic inner cylinder is divided into a first ceramic inner cylinder section and a second ceramic inner cylinder section, with a gap between the two sections; the first-stage collecting electrode assembly and the second-stage collecting electrode assembly are located in the first ceramic inner cylinder section, and the third-stage collecting electrode assembly is located in the second ceramic inner cylinder section.
3. An elliptical three-stage step-down collector electrode as described in claim 2, characterized in that, The second ceramic inner cylinder section has a ring-shaped structure protruding from one end near the first ceramic inner cylinder section towards the central axis; this is used to isolate the electric field between the second collector assembly and the third collector assembly.
4. An elliptical three-stage step-down collector electrode as described in claim 3, characterized in that, The first input channel is cuboid in shape, and its aperture matches the strip electron beam; the second and third input channels are cuboid in shape, and the output end face aperture of the second input channel is smaller than the input end face aperture of the third input channel; the opening shape of the first and second output ports is rectangular.
5. An elliptical three-stage step-down collector electrode as described in claim 4, characterized in that, The heat dissipation fins are evenly distributed along the circumference and have the same length as the metal outer cylinder; at the same time, cooling water is used to dissipate heat from the heat dissipation fins.
6. An elliptical three-stage step-down collector as described in claim 4 or 5, wherein the apex of the conical structure is rounded to prevent arcing at the tip.