A waveguide energy transmission structure for traveling wave tube and traveling wave tube

Abstract

The present invention provides a waveguide energy transmission structure for a traveling wave tube and a traveling wave tube. The waveguide energy transmission structure includes an energy transmission window; a first output waveguide located on one side of the energy transmission window and connected to the traveling wave tube's slow-wave structure; and a second output waveguide located on the other side of the energy transmission window. The inner wall of the first output waveguide is formed with a stepped waveguide transmission structure arranged along the waveguide's transmission direction. The first output waveguide includes a through hole arranged opposite the stepped waveguide transmission structure. The waveguide energy transmission structure also includes an inner conductor. The inner conductor passes through the through hole and is fixedly coupled to the end face of the stepped waveguide transmission structure adjacent to the through hole. The axis of the inner conductor is perpendicular to the waveguide's transmission direction. This waveguide energy transmission structure can reduce the size of the traveling wave tube.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave vacuum electronic devices, and more specifically to a waveguide energy transmission structure for a traveling wave tube and a traveling wave tube. Background Art

[0002] A traveling wave tube is a microwave vacuum electronic device that can amplify signals in different frequency bands. It has the characteristics of high power, wide bandwidth, high gain, and high efficiency. It has been widely used in electronic countermeasures, radar, satellite communications and other fields. Figure 5 As shown, a traveling wave tube (TWT) consists of five main components: an electron gun, a focusing magnetic system, a slow-wave structure, input and output couplers, and a collector. Its operating principle is that the electron gun generates an electron beam of the desired size and current. After exiting the electron gun, the electron beam passes through the elongated slow-wave structure. The high-frequency signal enters the TWT through the input coupler, forming a traveling wave that propagates along the slow-wave structure. The slow-wave structure reduces the phase velocity of the electromagnetic wave to approximately the same speed as the electrons, enabling interaction and energy exchange between the electron beam and the electromagnetic wave. Due to the focusing effect of the magnetic field, the electron beam travels along the slow-wave structure's axis. This process of electron propagation is accompanied by interaction with the electromagnetic wave, converting the electrons' kinetic energy into electromagnetic wave energy, thereby amplifying the input high-frequency signal. The high-frequency signal is output through the output coupler. The electrons, having transferred most of their energy, eventually strike the collector, where they are converted into heat energy.

[0003] However, the existing traveling wave tubes are too large in size and weight, making them difficult to manufacture and repair. At the same time, as various application fields develop towards smaller sizes, there is an increasing need to develop miniaturized traveling wave tubes. Summary of the Invention

[0004] In view of the above problems, an object of the present invention is to provide a waveguide energy transmission structure for a traveling wave tube, by which the size of the traveling wave tube can be reduced.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a waveguide energy transmission structure for a traveling wave tube, comprising:

[0007] Energy transmission window;

[0008] a first output waveguide located on one side of the energy transmission window and connected to the slow-wave structure of the traveling wave tube; and

[0009] a second output waveguide located on the other side of the energy transmission window;

[0010] A stepped waveguide transmission structure is formed on the inner wall of the first output waveguide and is arranged along the transmission direction of the waveguide;

[0011] The first output waveguide includes a through hole arranged opposite to the stepped waveguide transmission structure;

[0012] The waveguide energy transmission structure further includes an inner conductor;

[0013] The inner conductor passes through the through hole and is fixed to the end face of the stepped waveguide transmission structure close to the through hole; the axis of the inner conductor is perpendicular to the transmission direction of the waveguide.

[0014] In addition, a preferred solution is that the first output waveguide, the second output waveguide and the energy transmission window are coaxially arranged.

[0015] In addition, a preferred solution is that the feeding method of the waveguide energy transmission structure is a backfeed type.

[0016] In addition, a preferred solution is that the end of the second output waveguide close to the energy transmission window includes a first waveguide flange; the cross-section of the first waveguide flange is rectangular.

[0017] In addition, a preferred solution is that the size of the first waveguide flange is 19.1 mm*14 mm*1.2 mm.

[0018] In addition, a preferred solution is that the inner conductor and the stepped waveguide transmission structure are fixed together by brazing.

[0019] In addition, a preferred solution is that the energy transmission window includes a docking structure for connecting to the first waveguide flange; the size of the docking structure is 19.1mm*14mm*1.8mm.

[0020] In addition, a preferred solution is that the outer diameter of the energy transmission window is 15.5 mm.

[0021] Another object of the present invention is to provide a traveling wave tube, which includes the waveguide energy transmission structure described above.

[0022] In addition, a preferred solution is that the traveling wave tube includes a first connecting member fixedly combined with the slow wave structure, the first output waveguide includes a second connecting member, and the first connecting member is fixedly combined with the second connecting member.

[0023] The beneficial effects of the present invention are:

[0024] The present invention realizes signal transmission by connecting the stepped waveguide transmission structure with the inner conductor. At the same time, the axis of the inner conductor is perpendicular to the transmission direction of the waveguide, which directly realizes a 90° change in the signal transmission direction without the need for additional accessories to realize the steering of the transmitted signal. This greatly shortens the distance between the waveguide energy transmission structure and the traveling wave tube, effectively reduces the size of the traveling wave tube, promotes the miniaturization of the traveling wave tube, and expands the application range of the traveling wave tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0026] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0027] Figure 2 It is a schematic structural diagram of the first output waveguide of the present invention.

[0028] Figure 3 It is a schematic diagram of the cooperation between the present invention and the collecting electrode.

[0029] Figure 4 Schematic diagram of a waveguide conversion structure in the prior art.

[0030] Figure 5 It is a structural diagram of a traveling wave tube. DETAILED DESCRIPTION

[0031] 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 of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention.

[0032] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0033] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0034] In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0035] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0036] While existing traveling wave tubes (TWTs) can provide sufficiently high output power compared to solid-state microwave amplifiers, they require very high operating voltages, making them inconvenient to power up and use in practice. Furthermore, their size and weight make them inconvenient for users. Therefore, facing the challenge posed by solid-state microwave amplifiers, there is a growing need to develop practical, low-voltage, and highly reliable miniaturized TWTs. Microwave power modules (MPMs) use solid-state amplifiers as the excitation stage and traveling wave tubes as the output stage, integrating the solid-state amplifier and TWT. This integration combines the advantages of both solid-state and vacuum devices and has been widely used in various military and civilian fields, including electronic weapon systems and satellite communications. The development of MPMs also requires TWTs to be increasingly miniaturized. Miniaturizing TWTs can expand their application range.

[0037] Miniaturization of a traveling wave tube (TWT) can be achieved by miniaturizing its length (L), height (H), and width (W). For example, the length can be achieved by shortening the slow-wave structure, and the height can be achieved by reducing the radial dimensions of the electron gun, high-frequency band, and collector. In comparison, miniaturizing the TWT's width is more difficult. Reasonable miniaturization of the TWT's width is essential to fully utilize the MPM's internal space and improve its integration. The TWT's input and output devices, or the energy transmission structure, play a significant role in determining its width.

[0038] The output structure of a traveling wave tube (TWT) transmits the amplified RF signal to the next-stage equipment. A coaxial structure is generally used for lower frequencies or lower powers; a waveguide structure is used for lower powers. For high-power TWTs operating in the millimeter wave band (output power in the tens of watts or more), the signal output section uses a waveguide structure.

[0039] Reference Figure 4 As shown, the distance from the outer edge of the conventional waveguide energy transmission structure to the axial centerline of the TWT is 40.47 mm, and the distance from the transverse center axis of the conventional waveguide energy transmission structure to the axial centerline of the TWT is 27.72 mm. This makes the TWT excessively large. Furthermore, the rightmost waveguide assembly is non-detachable and cannot be recycled, increasing the cost of the TWT.

[0040] Furthermore, conventional waveguide energy transmission structures use direct feed, meaning the inner conductor is parallel to the transmission direction of the stepped waveguide within the waveguide to the left of the energy transmission window. To achieve axial power output from the traveling wave tube, an additional curved waveguide is required, further increasing the size of the traveling wave tube. Furthermore, the energy transmission window in existing technologies is located outside the collector, further increasing the size of the traveling wave tube.

[0041] In order to reduce the size of the traveling wave tube and promote the development of the traveling wave tube towards miniaturization, the present invention provides a waveguide energy transmission structure for the traveling wave tube, combined with Figures 1 to 3 As shown, specifically, the waveguide energy transmission structure for the traveling wave tube includes: an energy transmission window 11; a first output waveguide 12 located on one side of the energy transmission window 11 and connected to the slow wave structure of the traveling wave tube; and a second output waveguide 13 located on the other side of the energy transmission window 11; a stepped waveguide transmission structure 121 arranged along the transmission direction of the waveguide is formed on the inner wall of the first output waveguide 12; the first output waveguide 12 includes a through hole 122 arranged opposite to the stepped waveguide transmission structure 121; the waveguide energy transmission structure 10 also includes an inner conductor 14; the inner conductor 14 passes through the through hole 122 and is fixed to the end face of the stepped waveguide transmission structure 121 close to the through hole 122; the axis of the inner conductor 14 is perpendicular to the transmission direction of the waveguide. In this embodiment, a stepped impedance transformation step, namely a stepped waveguide transmission structure 121, is designed within the waveguide cavity of the first output waveguide 12. The inner conductor 14 is then fixed to the highest impedance transformation step. In other words, the inner conductor 14 is fixed to the end face of the stepped waveguide transmission structure 121 near the through hole 122. This achieves impedance transformation from coaxial low impedance to waveguide high impedance, and transmission mode conversion from coaxial TEM mode to waveguide TE mode. The inner conductor 14 is perpendicular to the waveguide transmission direction, eliminating the need for a waveguide bend in the traveling wavetube, thereby reducing the size of the traveling wavetube.

[0042] In order to reduce the width and height of the traveling wave tube to promote its miniaturization, specifically, the distance from the outer edge of the waveguide energy transmission structure 10 of the present invention to the axial centerline of the traveling wave tube is 24.45mm, while the distance in the prior art is 40.47mm. The present invention reduces the distance by 40%; the distance from the transverse center axis of the waveguide energy transmission structure 10 of the present invention to the axial centerline of the traveling wave tube is 14.88mm, which is 46% smaller than the 27.72mm in the prior art. This effectively reduces the size of the traveling wave tube, and the height of the waveguide energy transmission structure 10 in the traveling wave tube is reduced from 22.7mm to 19.1mm, a reduction of 3.6mm, or 16%. This is conducive to the miniaturization of traveling wave tubes and broadens the application scenarios of traveling wave tubes.

[0043] It can be understood that the energy transmission window 11 is an important component for the power output of the traveling wave tube. The function of the energy transmission window 11 is to separate the vacuum environment inside the tube from the external atmosphere and ensure that the radio frequency signal can pass through with low loss; the second output waveguide 13 is connected behind the energy transmission window 11 to connect to the external structure.

[0044] In a specific embodiment, the waveguide energy transmission structure 10 is fed in a backward-feed manner. The waveguide conversion feeding method is changed from direct-feed to backward-feed, i.e., the inner conductor is perpendicular to the transmission direction of the stepped waveguide transmission structure within the first output waveguide. This backward-feed waveguide energy transmission eliminates the need for a curved waveguide in the traveling wave tube, directly achieving a 90° shift in signal transmission direction. The first output waveguide 12, the second output waveguide 13, and the energy transmission window 11 are coaxially arranged, with the transverse centerline aligning and docking to achieve axial output of the traveling wave tube signal. Furthermore, the distance from the transverse center axis of the waveguide energy transmission structure 10 to the axial centerline of the traveling wave tube is reduced from 27.72 mm to 14.88 mm, a 45% reduction, thereby reducing the size of the traveling wave tube.

[0045] In one specific embodiment, the inner conductor 14 is fixed to the stepped waveguide transmission structure 121 by brazing. The lower end of the inner conductor 14 is welded to the helical wire of the traveling wave tube via a transition antenna, ensuring a good match between the slow-wave structure and the energy transmission structure. The upper end of the inner conductor 14 is vertically inserted into the end face of the stepped waveguide transmission structure 121 near the through hole 122, i.e., the highest step of the stepped waveguide transmission structure 121, which has a mating hole, and the inner conductor 14 is fixed by brazing.

[0046] In a specific embodiment, the end of the second output waveguide 13 near the energy transmission window 11 includes a first waveguide flange 131; the cross-section of the first waveguide flange 131 is rectangular. In this embodiment, the dimensions of the first waveguide flange 131 are 19.1 mm * 14 mm * 1.2 mm. To facilitate the miniaturization of the traveling wave tube, the middle portion of the second output waveguide 13 is a slender straight waveguide, with the first waveguide flange 131 and a standard waveguide flange at either end. The end face of the first waveguide flange 131 is a 19.1 mm * 14 mm rectangle. Compared to the 22.7 mm diameter circular waveguide flange used in the prior art to interface with the energy transmission window 11, the area of the first waveguide flange 131 is reduced by one-third. The highest position in the height direction of the traveling wave tube is the waveguide flange that interfaces with the energy transmission window 11. Since the end face of a standard waveguide flange is a square of 19.1 mm*19.1 mm, when the energy transmission window 11 interfaces with the second output waveguide 13, in order not to increase the height of the traveling wave tube while reducing its width, the long side (19.1 mm) of the first waveguide flange 131 is placed in the height direction of the traveling wave tube, and the short side (14 mm) is placed in the width direction of the traveling wave tube. As a result, the height dimension of the traveling wave tube is reduced from 22.7 mm to 19.1 mm, a reduction of 3.6 mm, or 16%. At the same time, the width dimension of the traveling wave tube is reduced from 22.7 mm to 14 mm, a reduction of 38%.

[0047] At the same time, in order to place the energy transmission window 11 and the first waveguide flange 131 into the narrow space between the collector 20 and the inner conductor 14, so as to further reduce the width of the traveling wave tube, the first waveguide flange 131 is designed to be thin, with a thickness of only 1.2 mm, which is 1 / 2 of the thickness of a conventional flange.

[0048] In one specific embodiment, the energy transmission window 11 includes a docking structure 111 for connecting to the first waveguide flange 131; the dimensions of the docking structure 111 are 19.1 mm * 14 mm * 1.8 mm. To facilitate the removable screw installation of the first waveguide flange 131, a rectangular docking structure 111 with dimensions of 19.1 mm * 14 mm * 1.8 mm is added to the energy transmission window 11. The docking structure 111 is positioned in the middle of the energy transmission window 11, not occupying the thickness of the energy transmission window 11. This ensures that the energy transmission window 11 and the first waveguide flange 131 can be placed in the narrow space in front of the collector 20, thereby facilitating the reduction of the size of the traveling wave tube.

[0049] In one specific embodiment, the second output waveguide 13 is threadedly connected to the energy transmission window 11, making the second output waveguide 13 removable and recyclable, thereby reducing the cost of the traveling wave tube. Specifically, after the energy transmission window 11 and the second output waveguide 13 are aligned at the mating surface, a docking structure 111 fixed in the middle of the energy transmission window 11 and the first waveguide flange 131 are secured together using four screws passing through corresponding threaded holes.

[0050] In a specific embodiment, the outer diameter of the energy transmission window 11 is 15.5 mm. In order to further reduce the width and height of the traveling wave tube, the energy transmission window 11 is miniaturized and designed to reduce its size so that the size of the energy transmission window 11 in the width direction of the traveling wave tube is Φ15.5 mm. Compared with the existing energy transmission window outer diameter of Φ22.7 mm, the size occupied by the energy transmission window 11 in the width direction of the traveling wave tube is reduced by 1 / 3, and the size occupied in the height of the traveling wave tube is reduced from 22.7 mm to 15.5 mm, a reduction of 7.2 mm. After the energy transmission window 11 is docked with the first waveguide flange 131, its size is Φ15.5 mm*7.03 mm, which is 2 / 3 smaller than the size of Φ22.7 mm*12.41 mm in the prior art. Compared with the existing layout in which the energy transmission window is placed outside the collector, the traveling wave tube using the waveguide energy transmission structure 10 of the present invention is significantly smaller.

[0051] As will be appreciated, the first output waveguide 12 is secured to the energy transmission window 11 via argon arc welding to ensure airtightness. The first waveguide flange 131 is brazed to the straight waveguide and standard waveguide flanges to form the second output waveguide 13, which does not require airtightness. This arrangement completes the connection between the waveguide energy transmission structure 10 for the traveling wave tube and the high-frequency band of the traveling wave tube, achieving power output in the axial direction of the traveling wave tube, promoting its miniaturization while reducing its cost.

[0052] The present invention also discloses a traveling wave tube (TWT) equipped with the aforementioned waveguide energy transmission structure 10. This TWT features miniaturization. Testing of the TWT with the waveguide energy transmission structure 10 demonstrated a voltage standing wave ratio (VSWR) below 1.4 within the 26 GHz to 40 GHz frequency band, demonstrating excellent impedance matching.

[0053] In addition, the traveling wave tube includes a first connector 15 fixedly coupled to the slow-wave structure, and the first output waveguide includes a second connector 16, which is fixedly coupled to the second connector 16. The first connector 15 and the second connector 16 are both cylindrical, and the second connector 16 is sleeved and fixed within the first connector 15. Specifically, an annular boss is formed within the first connector 15, and the bottom edge of the second connector 16 abuts the annular boss. The inner conductor 14 passes through the cavity formed by the first and second connectors 15, 16, and the bottom of the inner conductor 14 is overlap-welded to the helical wire of the slow-wave structure.

[0054] In summary, the present invention achieves signal transmission by connecting a stepped waveguide transmission structure to an inner conductor. Simultaneously, the axis of the inner conductor is perpendicular to the waveguide's transmission direction, directly shifting the signal transmission direction by 90° without the need for additional accessories to redirect the transmitted signal. This significantly shortens the distance between the waveguide energy transmission structure and the transverse center axis of the traveling wave tube, effectively reducing the size of the traveling wave tube, promoting its miniaturization, and expanding its application range. Furthermore, the fixing method between the second output waveguide and the energy transmission window has been improved from conventional argon arc welding to a removable screw connection, enabling recyclability and reducing the manufacturing cost of the traveling wave tube.

[0055] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A traveling wave tube, comprising a slow wave structure, a waveguide energy transmission structure and a collector, characterized in that: The feeding mode of the waveguide energy transmission structure is a backfeed mode, including: Energy transmission window; a first output waveguide located on one side of the energy transmission window and connected to the slow-wave structure of the traveling wave tube; and a second output waveguide located on the other side of the energy transmission window; A stepped waveguide transmission structure is formed on the inner wall of the first output waveguide and is arranged along the transmission direction of the waveguide; The first output waveguide includes a through hole arranged opposite to the stepped waveguide transmission structure; The waveguide energy transmission structure further includes an inner conductor; The inner conductor passes through the through hole and is fixed to the end face of the stepped waveguide transmission structure close to the through hole; the axis of the inner conductor is perpendicular to the transmission direction of the waveguide, and the lower end of the inner conductor is welded and fixed to the spiral wire of the slow-wave structure; The first output waveguide, the second output waveguide and the energy transmission window are coaxially arranged to realize axial output of the traveling wave tube signal; The end of the second output waveguide close to the energy transmission window includes a first waveguide flange; the cross section of the first waveguide flange is rectangular, and the short side of the first waveguide flange is located in the width direction of the traveling wave tube. The energy transmission window and the first waveguide flange are located between the collecting electrode and the inner conductor in the waveguide transmission direction.

2. The traveling wave tube according to claim 1, characterized in that The size of the first waveguide flange is 19.1 mm*14 mm*1.2 mm.

3. The traveling wave tube according to claim 1, wherein: The inner conductor and the stepped waveguide transmission structure are fixed together by soldering.

4. The traveling wave tube according to claim 1, wherein: The energy transmission window includes a docking structure for connecting to the first waveguide flange; the size of the docking structure is 19.1mm*14mm*1.8mm.

5. The traveling wave tube according to claim 1, wherein: The outer diameter of the energy transmission window is 15.5 mm.

6. The traveling wave tube according to claim 1, wherein the traveling wave tube comprises a first connecting member fixedly coupled to the slow wave structure, and the first output waveguide comprises a second connecting member, and the first connecting member is fixedly coupled to the second connecting member.

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