Slow wave structure, method for manufacturing slow wave structure, and slow wave circuit

Abstract

The slow wave structure and its preparation method and slow wave circuit are provided, and relate to the technical field of microwave and millimeter wave electric vacuum devices. The slow wave structure comprises a plurality of penetrating layers and a plurality of protruding layers. The plurality of penetrating layers respectively have penetrating through holes, and the plurality of protruding layers and the plurality of penetrating layers are alternately arranged along a running direction. Each protruding layer has a limiting through hole. The plurality of limiting through holes and the plurality of penetrating through holes form a serpentine slow wave channel which is in communication along the running direction, so that the electromagnetic wave incident to the slow wave channel is decelerated under the action of the slow wave channel to match the running speed of the electrons in the electron beam.

Description

Technical Field

[0001] This disclosure relates to the field of microwave and millimeter-wave vacuum electronic devices, and in particular to a slow-wave structure and its fabrication method, as well as a slow-wave circuit. Background Technology

[0002] Terahertz traveling wave tubes (TWTs), as high-power terahertz sources, are characterized by high power, high efficiency, and wide bandwidth. With the continuous improvement of TWT products' high-power, high-efficiency, and wide-bandwidth electromagnetic wave amplification capabilities in major atmospheric windows, various advanced short millimeter-wave and terahertz devices will be driven towards practical applications. The working principle of terahertz TWTs is the same as that of traditional TWTs, relying on electrons synchronized with electromagnetic waves to transfer energy to the electromagnetic waves for amplification. They mainly consist of an electron gun, a high-frequency interaction system, a collector, input / output devices, and a magnetic focusing system.

[0003] Due to the size coherence effect, microwave power devices become increasingly smaller at higher frequencies. For example, the slow-wave circuit width of a 220 GHz traveling-wave tube is only about 0.12 mm, while that at 1.03 THz it is about 0.03 mm. Traditional fabrication methods, such as precision micromilling, precision electrical discharge machining, deep reactive ion etching (DRIE), and ultraviolet lithography (UV-LIGA), all have limitations in terms of dimensional tolerances, surface roughness, geometric accuracy, residual stress, efficiency, and cost. The lack of high-quality high-frequency interaction components has become a major obstacle in the development of terahertz microwave power devices. Summary of the Invention

[0004] In view of this, the present disclosure provides a slow wave structure and its preparation method, as well as a slow wave circuit, which can improve the efficiency of standing wave interaction.

[0005] As one aspect of this disclosure, a slow-wave structure is provided, including a plurality of through layers, each having a through-hole; and a plurality of protruding layers, which are alternately installed with the plurality of through layers along the travel direction of the electron beam, each protruding layer having a limiting through-hole; wherein the plurality of limiting through-holes and the plurality of through-holes form a serpentine slow-wave channel communicating in the travel direction, such that electromagnetic waves incident on the slow-wave channel are decelerated under the action of the slow-wave channel to match the travel speed of electrons in the electron beam.

[0006] According to embodiments of this disclosure, the plurality of protruding layers include a plurality of first protruding layers and a plurality of second protruding layers. The plurality of through layers, together with the plurality of first protruding layers and the plurality of second protruding layers, form a plurality of periodic components arranged periodically along the travel direction. Each periodic component includes: two through layers; a first protruding layer installed between the two through layers; and a second protruding layer installed on one side of one of the two through layers opposite to the first protruding layer, such that a first limiting through hole of the first protruding layer and a second limiting through hole of the second protruding layer are respectively located on both sides of a through hole. The first limiting through hole and the second limiting through hole are both smaller than the through hole and are superimposed on the through hole on opposite sides of the through hole to form an interleaved double-gate slow wave structure.

[0007] According to embodiments of this disclosure, some of the through-holes and / or some of the restrictive holes have an angle of rotation about the travel axis in a plane perpendicular to the travel axis of the electron beam's trajectory, relative to the other through-holes and restrictive holes, so as to dynamically adjust the shape and direction of the slow wave.

[0008] According to embodiments of this disclosure, the thickness of at least one of the above-mentioned protruding layers is different from the thickness of the other above-mentioned protruding layers, and / or the thickness of at least one of the above-mentioned through-layers is different from the thickness of the other above-mentioned through-layers, so as to cause the period of the slow wave channel to jump, thereby suppressing oscillation.

[0009] According to embodiments of this disclosure, the thicknesses of the plurality of protruding layers and the plurality of penetrating layers gradually decrease along the direction of travel of the electron beam, thereby gradually reducing the period of the slow wave channel along the direction of travel to further reduce the propagation speed of the electromagnetic wave and further match the propagation speed with the travel speed of the electrons in the electron beam.

[0010] According to an embodiment of this disclosure, each of the aforementioned through-layers and each of the aforementioned protruding layers is provided with a mounting hole, so as to connect the plurality of the aforementioned through-layers and the plurality of the aforementioned protruding layers by means of an external mounting rod passing through the mounting hole in sequence.

[0011] As another aspect of the present disclosure, a slow-wave circuit is provided, comprising: a mounting assembly; two waveguide assemblies, one of which serves as an input waveguide and the other as an output waveguide, wherein each of the waveguide assemblies has an electromagnetic wave channel that allows electromagnetic wave transmission and an electronic channel that allows electron beam transmission; and any of the above-mentioned slow-wave structures, mounted between the two waveguide assemblies by the mounting assembly, wherein the input port of the slow-wave structure is connected to the first electromagnetic wave channel and the first electronic channel of the input waveguide, and the output port is connected to the second electromagnetic wave channel and the second electronic channel of the output waveguide.

[0012] According to an embodiment of the present disclosure, at least one of the two waveguide components includes a transmission waveguide having an internally formed electronic channel extending along the travel direction and communicating with the slow wave channel; and an end face waveguide abutting between the transmission waveguide and the slow wave structure; wherein the side of the transmission waveguide adjacent to the end face waveguide is recessed in a direction away from the slow wave structure, and an electromagnetic wave channel communicating with the slow wave channel is formed between the transmission waveguide and the end face waveguide.

[0013] According to an embodiment of the present disclosure, the mounting assembly includes a plurality of mounting rods and a plurality of fasteners, wherein at least two of the mounting rods are mounted from one of the two waveguide assemblies, through the slow wave structure, and in cooperation with the plurality of fasteners onto the other of the two waveguide assemblies.

[0014] As another aspect of the present disclosure, a method for preparing any of the above-mentioned slow-wave structures is provided, comprising:

[0015] Obtain the electron trajectory of the electron beam;

[0016] The length of the slow-wave structure is determined based on the aforementioned electron trajectory.

[0017] Slicing is performed along a direction perpendicular to the electron trajectory, and the thicknesses of multiple penetrating layers and multiple protruding layers are determined respectively. The number of the penetrating layers and the number of protruding layers are determined according to the length.

[0018] A plurality of first foils are determined based on the thickness of the plurality of the aforementioned through-layers, and a plurality of second foils are determined based on the thickness of the plurality of the aforementioned protruding layers;

[0019] Through holes and positioning holes are respectively formed on multiple of the aforementioned first foil materials to prepare multiple of the aforementioned through layers;

[0020] Multiple protruding layers are prepared by forming limiting through holes and positioning holes on multiple second foils, wherein a portion of the multiple protruding layers is designated as a first protruding layer and another portion of the multiple protruding layers is designated as a second protruding layer, and the limiting through holes are smaller than the through holes.

[0021] The positioning element passes through the positioning holes in each of the aforementioned through layers, each of the aforementioned first protruding layers, and each of the aforementioned second protruding layers, and the aforementioned two through layers, the aforementioned first protruding layers, and the aforementioned second protruding layers are alternately arranged, such that the first limiting through hole and the second limiting through hole overlap with the aforementioned through hole on opposite sides of the aforementioned through hole; and

[0022] The contact surfaces between adjacent through layers and protruding layers are welded to form a slow-wave structure.

[0023] According to the slow-wave structure of this disclosure, a flexible combination of multiple through-holes and multiple protruding layers allows for dynamic adjustment of the shape and direction of the slow wave. This is achieved by pre-rotating the through-holes and limiting through-holes angularly around the electron beam's trajectory in a plane perpendicular to the beam's axis of travel, based on the tearing characteristics of the electron beam's trajectory. This increases the interaction distance between the electromagnetic wave and the electron beam, thereby increasing the electron beam filling ratio to approach or even reach the theoretical electron filling ratio limit. This means more electrons can participate in the energy exchange process with the electromagnetic wave, thus improving the amplification efficiency and output power of the traveling wave tube. The increased electron beam filling ratio enables the terahertz traveling wave tube based on the slow-wave structure provided by this disclosure to provide higher output power, which is significant for applications requiring high power output. Furthermore, by employing a combination of multiple through-holes and multiple protruding layers, which can be made of readily available micron-sized foil materials (such as copper, silver, gold, etc.), the structure can be compatible with the structural requirements of 1 THz or even 2 THz traveling wave tube slow-wave circuits, exhibiting high frequency adaptability. Attached Figure Description

[0024] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0025] Figure 1 A perspective view of a slow-wave circuit according to an embodiment of the present disclosure is schematically shown;

[0026] Figure 2 A side view of a slow-wave circuit according to an embodiment of the present disclosure is shown schematically;

[0027] Figure 3 Schematic illustration Figure 2 A cross-sectional view of the slow-wave circuit shown in Figure AA;

[0028] Figure 4 Schematic illustration Figure 3 A partial enlarged view of part B of the sectional view shown;

[0029] Figure 5 A side view of a slow-wave structure according to an embodiment of the present disclosure is schematically shown;

[0030] Figure 6 Schematic illustration Figure 5 Partial three-dimensional half-section of the slow-wave structure shown.

[0031] Figure 7 The diagram illustrates the partitioning principle of a periodic component of a slow-wave structure according to an embodiment of the present disclosure.

[0032] Figure 8A perspective view of a through-layer according to an embodiment of the present disclosure is schematically shown;

[0033] Figure 9 A perspective view of a protruding layer according to an embodiment of the present disclosure is schematically shown;

[0034] Figure 10 A comparative diagram of a first protruding layer, a through layer, and a second protruding layer according to an embodiment of the present disclosure is shown schematically.

[0035] Figure 11 A comparative diagram of two first protruding layers according to an embodiment of the present disclosure is shown schematically;

[0036] Figure 12 A comparative diagram of two through-layers according to an embodiment of the present disclosure is shown schematically;

[0037] Figure 13 A comparative diagram of two second protruding layers according to an embodiment of the present disclosure is shown schematically;

[0038] Figure 14 A perspective view of an end-face waveguide according to an embodiment of the present disclosure is schematically shown;

[0039] Figure 15 A perspective view of a first waveguide according to an embodiment of the present disclosure is schematically shown; and

[0040] Figure 16 A flowchart illustrating a method for fabricating a slow-wave structure according to an embodiment of the present disclosure is shown schematically.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1-Slow wave structure;

[0043] 11-Penetrating layer;

[0044] 111 - Through hole;

[0045] 112 - Mounting hole;

[0046] 113 - Positioning hole;

[0047] 12-Protruding layer;

[0048] 121 - First protruding layer;

[0049] 1211 - First limiting through hole;

[0050] 1212 - Mounting hole;

[0051] 1213 - Positioning hole;

[0052] 122 - Second protruding layer;

[0053] 1221 - Second limiting through hole;

[0054] 13-Cycle Components;

[0055] 2-Install components;

[0056] 21-Mounting rod;

[0057] 22-Fasteners;

[0058] 3-Waveguide assembly;

[0059] 31-Transmission waveguide;

[0060] 311 - First Waveguide;

[0061] 312 - Second waveguide;

[0062] 32-End face waveguide;

[0063] 321 - Entrance / Exit;

[0064] 322 - Positioning hole;

[0065] 323 - Mounting hole;

[0066] 33 - Electromagnetic wave channel;

[0067] 34-Electronic Channel;

[0068] 35 - Mounting hole;

[0069] 36 - Flange opening;

[0070] 37 - Positioning hole. Detailed Implementation

[0071] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0072] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0073] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0074] When using expressions such as "at least one of A, B, and C," the meaning should generally be interpreted according to the understanding of someone skilled in the art. For example, "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C. Similarly, when using expressions such as "at least one of A, B, or C," the meaning should generally be interpreted according to the understanding of someone skilled in the art. For example, "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C.

[0075] It should also be noted that the directional terms mentioned in the embodiments, such as "up," "down," "front," "back," "left," and "right," are only for reference to the directions in the accompanying drawings and are not intended to limit the scope of protection of this disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted where they may cause confusion in understanding this disclosure.

[0076] In the process of realizing this disclosure, it was discovered that the electron trajectory of a single-circular tube structure is approximately spindle-shaped, and deforms with different cross-sections as it travels. However, in the structural design of terahertz traveling-wave tube slow-wave circuits in related technologies, due to the need to consider the capabilities of traditional processing methods, the slow-wave channels are all of constant cross-section, making dynamic adjustment based on the electron propagation trajectory impossible. Traditional processing methods for slow-wave structures mainly include precision micro-milling, precision electrical discharge machining, wire EDM, deep reactive ion etching (DRIE), and ultraviolet lithography (UV-LIGA).

[0077] Precision micromilling technology uses high-speed rotating milling cutters to cut materials, resulting in high machining accuracy and good surface quality. In the machining of folded waveguide components, high-speed milling can ensure that the shape and dimensional accuracy of the parts meet design requirements. However, due to the limitation of the milling cutter diameter, it is not very suitable for machining structures above 340 GHz.

[0078] Precision electrical discharge machining (EDM) is a process that uses the heat energy generated by electrical discharge to melt and vaporize the workpiece material, thereby removing excess material to achieve the machining objective. While this method can produce very precise dimensions, it usually leaves a certain degree of roughness on the machined surface, resulting in a relatively high surface roughness.

[0079] Slow wire EDM, also known as low-speed wire EDM, is a high-precision machining method that uses a continuously moving fine metal wire (electrode wire) to perform pulsed spark discharge on the workpiece, thereby cutting the workpiece into its final form. However, this machining method uses relatively thin electrode wires, which are relatively expensive, and the thin electrode wires are prone to breakage during the machining process, making it impossible to guarantee continuity.

[0080] Deep reactive ion etching (DRIE) technology can achieve etching depths of up to several hundred micrometers, showing promise in the manufacture of folded waveguide components requiring deep microstructures. This high etching depth ensures that the components can meet the requirements of complex three-dimensional structural designs. However, the etching effect of DRIE technology is affected by various process parameters, such as the etching / passivation time ratio, pressure, and power. To obtain the best etching results, these parameters need to be finely adjusted and optimized. In addition, selecting appropriate etching gases and mask materials is also crucial for improving processing quality.

[0081] UV-LIGA technology is a microfabrication technique that combines deep X-ray lithography, electroforming, and micro-electrical discharge machining. Since LIGA technology can only process rectangular structures, when designing folded waveguide components, it may be necessary to consider designing the electron channel as a rectangular structure to reduce the number of mask replacements. However, the actual electron trajectory is a single cylinder, planar multi-cylinder, or spindle shape, etc., and a rectangular electron channel would reduce the beam-wave interaction efficiency.

[0082] Table 1 shows a comparison of the geometric measurement accuracy, surface roughness, processing cycle, processing cost, and technical specifications achievable by the above processing methods.

[0083] Table 1:

[0084]

[0085] Figure 1 A perspective view of a slow-wave circuit according to an embodiment of the present disclosure is schematically shown. Figure 2 A side view of a slow-wave circuit according to an embodiment of the present disclosure is schematically shown. Figure 3 Schematic illustration Figure 2 The diagram shows a cross-sectional view of the slow-wave circuit AA. Figure 4 Schematic illustration Figure 3 A partial enlarged view of part B of the sectional view shown.

[0086] As one aspect of this disclosure, a slow-wave structure 1 is provided, such as... Figures 1 to 4 As shown, the slow-wave structure 1 includes multiple through-layers 11 and multiple protruding layers 12. Each of the multiple through-layers 11 has a through-hole 111. The multiple protruding layers 12 and the multiple through-layers 11 are aligned with the electron beam's propagation direction (the propagation direction is...). Figure 3The layers (in the direction indicated by the middle arrow) are installed alternately, and each protruding layer 12 has a limiting through-hole. Multiple limiting through-holes and multiple through-holes 111 form a serpentine slow-wave channel connected in the direction of travel. This causes the electromagnetic waves incident on the slow-wave channel to decelerate under the influence of the slow-wave channel, matching the speed of the electrons in the electron beam. This, in turn, causes the decelerated electromagnetic waves to interact with the electrons, converting the kinetic energy of the electron beam into the power of the electromagnetic waves, thereby amplifying the electromagnetic waves.

[0087] According to the slow-wave structure of this disclosure, a flexible combination of multiple through-holes and multiple protruding layers allows for dynamic adjustment of the shape and direction of the slow wave. This is achieved by pre-rotating the through-holes and limiting through-holes angularly around the electron beam's trajectory in a plane perpendicular to the beam's axis of travel, based on the tearing characteristics of the electron beam's trajectory. This increases the interaction distance between the electromagnetic wave and the electron beam, thereby increasing the electron beam filling ratio to approach or even reach the theoretical electron filling ratio limit. This means more electrons can participate in the energy exchange process with the electromagnetic wave, thus improving the amplification efficiency and output power of the traveling wave tube. The increased electron beam filling ratio enables the terahertz traveling wave tube based on the slow-wave structure provided by this disclosure to provide higher output power, which is significant for applications requiring high power output. Furthermore, by employing a combination of multiple through-holes and multiple protruding layers, which can be made of readily available micron-sized foil materials (such as copper, silver, gold, etc.), the structure can be compatible with the structural requirements of 1 THz or even 2 THz traveling wave tube slow-wave circuits, exhibiting high frequency adaptability.

[0088] According to embodiments of this disclosure, the electromagnetic wave can be a microwave.

[0089] According to the slow-wave structure provided in the embodiments of this disclosure, the through-hole and the limiting through-hole can be designed as rectangular, spindle-shaped, or circular non-axisymmetric cross sections based on the cross section of the electron trajectory in the direction perpendicular to the direction of electron beam travel. They can also rotate according to the rotation of the electron trajectory.

[0090] According to embodiments of this disclosure, the shape of the slow-wave channel matches the trajectory of the electron beam.

[0091] Figure 5 A side view of a slow-wave structure according to an embodiment of the present disclosure is schematically shown. Figure 6 Schematic illustration Figure 5 The image shows a partial three-dimensional half-section of the slow-wave structure CC. Figure 7 The diagram illustrates the partitioning principle of a periodic component of a slow-wave structure according to an embodiment of the present disclosure.

[0092] According to embodiments of this disclosure, such as Figures 5 to 7As shown, the plurality of protruding layers 12 include a plurality of first protruding layers 121 and a plurality of second protruding layers 122. A plurality of through layers 11, together with the plurality of first protruding layers 121 and the plurality of second protruding layers 122, form a plurality of periodic components 13 arranged periodically along the travel direction. Each periodic component 13 includes two through layers 11, a first protruding layer 121, and a second protruding layer 122. The first protruding layer 121 is installed between the two through layers 11, and the second protruding layer 122 is installed on one side of one of the two through layers 11 opposite to the first protruding layer 121, such that the first limiting through hole 1211 of the first protruding layer 121 and the second limiting through hole 1221 of the second protruding layer 122 are respectively located on both sides of a through hole 111. The first limiting through hole 1211 and the second limiting through hole 1221 are both smaller than the through hole 111 and are superimposed on opposite sides of the through hole 111 to form an interleaved double-gate slow-wave structure.

[0093] like Figures 5 to 7 As shown, the first limiting vias 1211 of the plurality of first protruding layers 121 and the second limiting vias 1221 of the plurality of second protruding layers 122 are all smaller than the cross-sectional area of ​​the through vias 111 of the plurality of through layers 11. In a periodic component 13, the first limiting vias 1211 and the second limiting vias 1221 are stacked on opposite sides of the through vias 111, which is equivalent to the first protruding layers 121 and the second protruding layers 122 protruding towards each other on opposite sides of the through vias 111 and partially blocking the through vias in the direction of travel, thereby forming an interleaved dual-gate slow wave structure.

[0094] According to embodiments of this disclosure, the length of the periodic component can be adjusted by adjusting the thicknesses of the plurality of through layers, the plurality of first protruding layers, and the plurality of second protruding layers. Figure 7 The horizontal dimension of the periodic component (as shown in the diagram) is used to match the periodicity of the periodic component with the periodicity of the electron's trajectory.

[0095] Figure 8 A perspective view of a through-layer according to an embodiment of the present disclosure is schematically shown. Figure 9 A perspective view of a protruding layer according to an embodiment of the present disclosure is shown schematically.

[0096] According to embodiments of this disclosure, such as Figure 8 and Figure 9 As shown, each through layer 11 and each protruding layer 12 is provided with mounting holes (e.g., Figure 8 Mounting holes 112 and Figure 9 The mounting holes 1212 in the middle are used to connect multiple through layers and multiple protruding layers by passing an external mounting rod through the mounting holes in sequence.

[0097] In one of the illustrated embodiments, such as Figure 8 and Figure 9 As shown, each through layer 11 and each protruding layer 12 is provided with two spaced-apart mounting holes. It is understood that the number of mounting holes can be adjusted according to actual needs.

[0098] According to embodiments of this disclosure, such as Figure 8 and Figure 9 As shown, each through layer and each protruding layer is provided with positioning holes spaced apart from the mounting holes (e.g., Figure 8 Positioning hole 113 and Figure 9 The positioning holes 1213 in the middle are used to position the multiple through layers 11 and multiple protruding layers 12 by means of positioning elements (e.g., pins).

[0099] In one of the illustrated embodiments, such as Figure 8 and Figure 9 As shown, each through-layer 11 and each protruding layer 12 is provided with four positioning holes spaced apart from the limiting through-holes or through-holes in the circumferential direction along the axis of the electron beam's travel direction. It can be understood that the number of positioning holes can be adjusted according to actual needs.

[0100] Figure 10 A comparative diagram of a first protruding layer, a through layer, and a second protruding layer according to an embodiment of the present disclosure is shown schematically.

[0101] According to embodiments of this disclosure, such as Figure 10 As shown, the distance between lines L1 and L2 is the dimension of the through-hole in the direction perpendicular to the electron beam's travel direction. The dimension of the through-hole's cross-section can be greater than half the dimension of the through-hole's cross-section and less than the dimension of the through-hole's cross-section. This creates a continuous, straight channel extending around the centerline of the through-hole.

[0102] In some embodiments, the cross-sectional shape of the through hole can be rectangular, square, circular, racetrack-shaped, or elliptical, while the shape of the limiting through hole matches the shape of the through hole. The size of the limiting through hole's cross-section is greater than half the size of the through hole's cross-section and less than the size of the through hole's cross-section, and overlaps with the through hole on opposite sides of the through hole.

[0103] Figure 11 A comparative diagram of two first protruding layers according to an embodiment of the present disclosure is shown schematically. Figure 12 A comparative diagram of two through-layers according to an embodiment of the present disclosure is illustrated schematically. Figure 13 A comparative diagram of two second protruding layers according to an embodiment of the present disclosure is shown schematically.

[0104] According to embodiments of this disclosure, such as Figure 11 As shown, Figure 11 (a) in the image is a side view of one of the first protrusions in a slow-wave structure. Figure 11 Image (a) is a side view of another first protrusion layer among multiple first protrusion layers in a slow-wave structure. A comparison of these two first protrusion layers shows that... Figure 11 The first limiting via of the first protruding layer in (a) is relative to Figure 11 In (b), the first limiting aperture of the first protruding layer has a deflection angle about the travel axis in a plane perpendicular to the travel axis of the electron beam.

[0105] like Figure 12 As shown, Figure 12 (a) in the image is a side view of one of the multiple through-layers in a slow-wave structure. Figure 12 Image (b) is a side view of another through-layer in a slow-wave structure. A comparison of these two through-layers shows that... Figure 12 The through-hole of the penetrating layer in (a) is relative to Figure 12 In (b), the through-hole of the through layer has a deflection angle about the travel axis in a plane perpendicular to the travel axis of the electron beam.

[0106] like Figure 13 As shown, Figure 13 (a) in the image is a side view of one of the multiple second protrusions in the slow-wave structure. Figure 13 Image (a) is a side view of another second protruding layer among multiple first protruding layers in a slow-wave structure. A comparison of these two second protruding layers shows that... Figure 13 The second limiting via in (a) of the second protruding layer relative to Figure 13 The second limiting aperture of the second protrusion in (b) has a deflection angle about the travel axis in a plane perpendicular to the travel axis of the electron beam.

[0107] like Figures 11 to 13 As shown, based on the tearing characteristics of the electron beam's trajectory, some of the through-holes and / or some of the restrictive holes have an angle of rotation about the travel axis in a plane perpendicular to the travel axis of the electron beam's trajectory, relative to the other through-holes and restrictive holes, in order to dynamically adjust the shape and direction of the slow wave and increase the interaction distance between the electromagnetic wave and the electron beam.

[0108] According to embodiments of this disclosure, the thickness of at least one protruding layer 12 is different from the thickness of other protruding layers 12, and / or the thickness of at least one through layer 11 is different from the thickness of other through layers 11, causing the period of the slow wave channel to form a jump, so as to suppress undesirable modes and oscillations that may reduce the performance and stability of the slow wave circuit.

[0109] In the process of realizing this disclosure, it was discovered that after electrons transfer some of their energy to microwaves, their speed slows down and their trajectories diverge.

[0110] According to embodiments of this disclosure, the thicknesses of the plurality of protruding layers 12 and the plurality of penetrating layers 11 gradually decrease along the direction of electron beam travel, thereby gradually reducing the period of the slow wave channel along the direction of travel, so as to further reduce the propagation speed of electromagnetic waves and further match the propagation speed with the travel speed of electrons in the electron beam.

[0111] As another aspect of this disclosure, a slow-wave circuit is provided. For example... Figures 1 to 4 As shown, the slow-wave circuit includes a mounting assembly 2, two waveguide assemblies 3, and any of the aforementioned slow-wave structures 1. One of the two waveguide assemblies 2 serves as an input waveguide, and the other as an output waveguide. Each waveguide assembly 2 has an electromagnetic wave channel 33 that allows electromagnetic wave transmission and an electronic channel 34 that allows electron beam transmission. The aforementioned slow-wave structure 1 is mounted between the two waveguide assemblies 3 via the mounting assembly 2. The input port of the slow-wave structure 1 is connected to the first electromagnetic wave channel and the first electronic channel of the input waveguide, and the output port is connected to the second electromagnetic wave channel and the second electronic channel of the output waveguide.

[0112] According to embodiments of this disclosure, an input waveguide is located at the input port of the slow-wave circuit and has an input terminal for guiding external electromagnetic waves and electron beams into the slow-wave circuit. An output waveguide is located at the output port of the slow-wave circuit and has an output channel for extracting amplified electromagnetic waves from the slow-wave circuit.

[0113] Figure 14 A perspective view of an end-face waveguide according to an embodiment of the present disclosure is shown schematically.

[0114] According to embodiments of this disclosure, such as Figures 1 to 4 as well as Figure 14 As shown, at least one of the two waveguide components 3 includes a transmission waveguide 31 and an end-face waveguide 32. An electronic channel 34 extending along the travel direction and communicating with the slow-wave channel is formed inside the transmission waveguide 31, and the end-face waveguide 32 abuts against the transmission waveguide 31 and the slow-wave structure 1. The side of the transmission waveguide 31 adjacent to the end-face waveguide 32 is recessed away from the slow-wave structure 1, forming an electromagnetic wave channel 33 communicating with the slow-wave channel between the transmission waveguide 31 and the end-face waveguide 32.

[0115] In one illustrative embodiment, the cross-section of the electromagnetic wave channel in the direction perpendicular to the propagation direction of the electromagnetic wave is rectangular.

[0116] According to embodiments of this disclosure, the cross-sectional dimension of the electromagnetic wave channel on the input waveguide in the direction perpendicular to the propagation direction of the electromagnetic wave decreases gradually in the propagation direction of the electromagnetic wave, gradually transitioning to the cross-sectional dimension of the slow wave channel. Conversely, the cross-sectional dimension of the electromagnetic wave channel on the output waveguide in the direction perpendicular to the propagation direction of the electromagnetic wave increases gradually in the propagation direction of the electromagnetic wave, ensuring the continuity of the slow wave circuit.

[0117] Figure 15 A perspective view of a first waveguide according to an embodiment of the present disclosure is shown schematically.

[0118] According to embodiments of this disclosure, such as Figures 1-3 as well as Figure 15 As shown, the transmission waveguide 31 may include a first waveguide 311 and a second waveguide 312. The first waveguide 311 is installed on the side of the end-face waveguide 32 opposite to the slow-wave structure 1, forming an electromagnetic wave channel 33 between itself and the end-face waveguide 32. An electron channel 34 extending along the direction of electron beam travel and communicating with the electromagnetic wave channel 33 is formed on the first waveguide 311. The second waveguide 312 is spatially spaced from the slow-wave structure 1 and is installed on the side of the end-face waveguide 32 opposite to the first waveguide 311, for cooperating with the first waveguide 311 to fix the end-face waveguide 32.

[0119] In one illustrative embodiment, the surfaces of the first and second waveguides on the side away from the slow-wave structure are recessed inward to form a plurality of flange holes to facilitate connection with external devices via a connecting device (e.g., a pin).

[0120] In one illustrative embodiment, the extension direction of the electromagnetic wave channel may be perpendicular to the extension direction of the electronic channel.

[0121] In the process of realizing this disclosure, it was discovered that if the available length for gradient is limited (that is, the length of the electromagnetic wave channel is limited), such as within 3:1, large reflections may occur.

[0122] The slow-wave structure provided in this disclosure allows waveguide components to be designed with a sufficiently long gradient space, with the available gradient length reaching 10:1 or more.

[0123] like Figure 14 As shown, an inlet / outlet 321 is provided on the end face waveguide to allow electromagnetic waves and electron beams to enter or exit.

[0124] In one illustrative embodiment, the size of the entrance / exit can be the same as the size of the through-hole or the limiting through-hole.

[0125] According to embodiments of this disclosure, such as Figures 1-3 As shown, the mounting assembly 2 includes a plurality of mounting rods 21 and a plurality of fasteners 22. At least two of the mounting rods 21 are mounted from one of the two waveguide assemblies 3, through the slow wave structure 1, and in cooperation with the plurality of fasteners 22 onto the other of the two waveguide assemblies 3.

[0126] In one illustrative embodiment, such as Figure 15 As shown, the first waveguide 311 has six mounting holes 35. Figure 15 From the perspective shown, the two mounting holes 35 in the middle allow two mounting rods 21 to pass through respectively to mount the slow-wave structure 1 and another waveguide assembly. The four mounting holes at the top and bottom allow four mounting rods 21 to pass through respectively, cooperating with multiple fasteners to secure the other waveguide assembly. It is understood that the number of mounting holes 35 can be adjusted according to actual needs.

[0127] According to embodiments of this disclosure, multiple mounting rods and multiple fasteners are used to support the slow-wave circuit, ensuring the position and stability of the slow-wave circuit inside the traveling wave tube.

[0128] In one illustrative embodiment, the mounting element can be a screw, and the fastener can be a nut.

[0129] Figure 16 A flowchart illustrating a method for fabricating a slow-wave structure according to an embodiment of the present disclosure is shown schematically.

[0130] As another aspect of the present disclosure, a method for preparing any of the above-described slow-wave structures is provided, the method comprising operations S160-S167.

[0131] During operation of S160, the electron trajectory of the electron beam is acquired.

[0132] In operation S161, the length of the slow-wave structure is determined based on the electron trajectory.

[0133] In operation S162, slices are made along the direction perpendicular to the electron trajectory, and the thicknesses of multiple through layers and multiple protrusion layers are determined respectively. The number of through layers and protrusion layers is determined according to the length.

[0134] In operation S163, a plurality of first foils are determined based on the thickness of the plurality of through layers, and a plurality of second foils are determined based on the thickness of the plurality of protruding layers.

[0135] In operation S164, through holes and positioning holes are respectively opened on multiple first foils to prepare multiple through layers.

[0136] In operation S165, limiting through holes and positioning holes are respectively opened on multiple second foils to prepare multiple protruding layers, wherein a portion of the multiple protruding layers is used as a first protruding layer, and another portion of the multiple protruding layers is used as a second protruding layer, and the limiting through holes are smaller than the through holes.

[0137] In operation S166, the positioning member passes through the positioning holes on each through layer, each first protruding layer and each second protruding layer, and alternates between every two through layers, first protruding layers and second protruding layers, so that the first limiting through hole and the second limiting through hole overlap with the through hole on opposite sides of the through hole.

[0138] In operation S167, the contact surfaces between adjacent through layers and protruding layers are welded to form a slow-wave structure.

[0139] The method for fabricating the slow-wave structure according to the embodiments of this disclosure utilizes mature socially available instruments and equipment, requires inexpensive raw materials, offers flexible processing and assembly methods, and has a sufficiently small limiting size. Even with the limitation of size coherence effects, the slow-wave structure can still achieve an extremely high interaction frequency of 1-2 THz. The electron channel of the slow-wave structure can be pre-rotated angularly based on the tearing characteristics of the electron beam trajectory, dynamically adjusting the shape and direction of the electron channel to increase the interaction distance. Alternatively, based on the electron velocity distribution, a periodically varying or abruptly changing slow-wave circuit can be designed to suppress oscillations and further improve electron efficiency, allowing more electron energy to be transferred to the electromagnetic wave. This will provide strong support for improving the performance stability, reliability, and electromagnetic wave amplification capability of terahertz traveling-wave tubes, promoting the widespread application of terahertz technology in fields such as communication and radar.

[0140] According to embodiments of this disclosure, operations S164 to S165 further include forming mounting holes on the first foil and the second foil, respectively.

[0141] According to an embodiment of this disclosure, in operation S165, a portion of the plurality of protruding layers serves as a first protruding layer, and another portion of the plurality of protruding layers is flipped 180° to serve as a second protruding layer. It is understood that the first protruding layer can also be prepared using a second foil, and the second protruding layer can be prepared using a third foil.

[0142] According to embodiments of this disclosure, the thickness of the end-face waveguide can also be determined based on the electron trajectory of the electron beam, and a fourth foil material can be determined. Inlet / outlet holes, positioning holes, and mounting holes are then formed on the fourth foil material.

[0143] According to embodiments of this disclosure, the slow-wave structure is assembled and positioned and locked to the waveguide assembly using a mounting assembly under an imager to fabricate a slow-wave circuit.

[0144] According to embodiments of this disclosure, the preparation method further includes determining the size of the through-hole and the limiting through-hole based on the electronic trajectory.

[0145] In one illustrative embodiment, diffusion welding is used to weld the contact surfaces between adjacent through layers and protruding layers.

[0146] According to embodiments of this disclosure, based on the tearing characteristics of the electron trajectory, at least a portion of the through-holes and at least a portion of the restricting holes can be rotated angularly around the axis in a plane perpendicular to the axis of the electron beam's travel direction, thereby dynamically adjusting the shape and direction of the slow wave and increasing the beam interaction distance between the electromagnetic wave and the electrons.

[0147] According to embodiments of this disclosure, the length of the slow-wave circuit can be matched to the travel of the electron beam to ensure that the electron beam has sufficient time to exchange energy with the electromagnetic wave throughout the travel.

[0148] In one illustrative embodiment, a method for fabricating a slow-wave circuit for a 220 GHz traveling-wave tube is provided, comprising:

[0149] Obtain the electron trajectory of the electron beam.

[0150] The length of the slow-wave structure is determined based on the electron trajectory.

[0151] Slice along a direction perpendicular to the electron trajectory, determine the thickness of multiple penetrating layers and multiple protruding layers, and determine the number of penetrating layers and protruding layers according to the length.

[0152] Select appropriate copper foil based on the thickness of each through layer and each protruding layer. The copper foil should have uniform thickness and good surface roughness. For example, the thickness uniformity can be better than 1 micrometer and the surface roughness can be better than Ra0.3.

[0153] In one illustrative embodiment, a thickness of 0.19 mm can be used for the through layer, and 0.14 mm for the protruding layer and end-face waveguide.

[0154] Furthermore, when using periodic jump or gradual change techniques, it is necessary to continue selecting copper foil of different thicknesses and specifications.

[0155] The patterns on each copper sheet are precisely cut using femtosecond or picosecond lasers and high-speed micro-milling. These patterns include through holes, positioning holes, and mounting holes on the through layer, as well as limiting through holes, positioning holes, and mounting holes on the protruding layer.

[0156] Before stacking, the thickness of each piece of material is checked using high-precision measuring equipment (such as a laser thickness gauge), and defective products are rejected. During the stacking process, an online thickness monitoring system is used to detect and adjust the thickness of each layer in real time to ensure that the deviation is within the allowable range. For areas with large thickness deviations, local grinding, filling, or re-stacking can be used for correction.

[0157] Under the imaging system, each through layer and each protruding layer is precisely assembled, positioned, and locked using a precision adjustment mechanism.

[0158] The staggered dual-grid slow-wave circuit and the two waveguide components are connected using screws and nuts. During the connection process, a coordinate measuring machine or image analyzer is used for detection, and attention should be paid to adjusting the perpendicularity of the electromagnetic wave channel.

[0159] For diffusion welding of the contact surfaces of each cross-section, typical process parameters are: diffusion pressure 0.2 MPa, diffusion temperature 850℃, and holding time 60 min. Understandably, these process parameters can be selected according to actual needs.

[0160] The parameters of the cold-tested slow-wave circuit are used to verify whether the prepared sample meets the design requirements.

[0161] Cut away the surrounding process structure and retain the core slow-wave circuit.

[0162] According to the slow-wave circuit fabrication method provided in this disclosure, the laser cutting machine, micro-milling machining center, image analyzer, laser thickness gauge, coordinate measuring machine, and diffusion welding furnace used are all mature equipment with readily available supporting equipment. The cutting, assembly, and welding processes of the slow-wave circuit provided in this disclosure can all be completed within hours, while traditional photolithography or electrical discharge machining methods require at least several weeks, and sometimes up to six months, to complete the formation of a structure with hundreds of layers. Therefore, compared to traditional photolithography or electrical discharge machining methods, this method improves fabrication efficiency and shortens the fabrication cycle.

[0163] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. The scope of this disclosure is defined by the appended claims and their equivalents. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A slow-wave structure, characterized in that, include: Multiple through layers, each with a through-hole; as well as Multiple protruding layers are alternately mounted with multiple through layers along the direction of electron beam travel, each protruding layer having a limiting through-hole; The plurality of limiting through holes and the plurality of through holes form a serpentine slow-wave channel that is connected in the direction of travel, so that the electromagnetic waves incident on the slow-wave channel are decelerated under the action of the slow-wave channel to match the travel speed of the electrons in the electron beam. Some of the through-holes and / or some of the restrictive holes have an angle of rotation about the travel axis in a plane perpendicular to the travel axis of the electron beam's trajectory, relative to the other through-holes and restrictive holes, so as to dynamically adjust the shape and direction of the slow wave.

2. The slow-wave structure according to claim 1, characterized in that, The plurality of protruding layers include a plurality of first protruding layers and a plurality of second protruding layers. The plurality of through layers, together with the plurality of first protruding layers and the plurality of second protruding layers, form a plurality of periodic components arranged periodically along the direction of travel. Each periodic component includes: Two through layers; A first protruding layer is installed between the two through layers; and The second protruding layer is installed on one side of one of the two through layers opposite to the first protruding layer, such that the first limiting through hole of the first protruding layer and the second limiting through hole of the second protruding layer are respectively located on both sides of one of the through holes; The first and second limiting through holes are both smaller than the through hole and are stacked on opposite sides of the through hole to form an interleaved double-grid slow wave structure.

3. The slow-wave structure according to claim 1 or 2, characterized in that, The thickness of at least one of the protruding layers differs from the thickness of the other protruding layers, and / or the thickness of at least one of the through layers differs from the thickness of the other through layers, causing a jump in the period of the slow wave channel to suppress oscillations.

4. The slow-wave structure according to claim 1 or 2, characterized in that, The thickness of the plurality of protruding layers and the thickness of the plurality of penetrating layers gradually decrease along the direction of travel of the electron beam, thereby gradually reducing the period of the slow wave channel along the direction of travel, so as to further reduce the propagation speed of the electromagnetic wave and further match the propagation speed with the travel speed of the electrons in the electron beam.

5. The slow-wave structure according to claim 1, characterized in that, Each of the through layers and each of the protruding layers is provided with a mounting hole, so that multiple through layers and multiple protruding layers can be connected by passing an external mounting rod through the mounting hole in sequence.

6. A slow-wave circuit, characterized in that, include: Install components; Two waveguide components, one of which serves as an input waveguide and the other as an output waveguide, wherein each of the waveguide components has an electromagnetic wave channel that allows electromagnetic wave transmission and an electron channel that allows electron beam transmission. as well as The slow-wave structure as described in any one of claims 1-5 is installed between two waveguide components via the mounting assembly, wherein the input port of the slow-wave structure is connected to the first electromagnetic wave channel and the first electronic channel of the input waveguide, and the output port is connected to the second electromagnetic wave channel and the second electronic channel of the output waveguide.

7. The slow-wave circuit according to claim 6, characterized in that, At least one of the two waveguide components includes: A transmission waveguide, internally forming an electronic channel extending along the travel direction and communicating with the slow-wave channel; and An end-face waveguide abuts between the transmission waveguide and the slow-wave structure; The transmission waveguide has a side adjacent to the end face waveguide that is recessed away from the slow wave structure, forming an electromagnetic wave channel that communicates with the slow wave channel between the transmission waveguide and the end face waveguide.

8. The slow-wave circuit according to claim 6, characterized in that, The installation components include: Multiple mounting rods and multiple fasteners, wherein at least two of the mounting rods are mounted from one of the two waveguide assemblies, through the slow wave structure, and by cooperating with the multiple fasteners onto the other of the two waveguide assemblies.

9. A method for preparing a slow-wave structure as described in any one of claims 1-5, characterized in that, include: Obtain the electron trajectory of the electron beam; The length of the slow-wave structure is determined based on the electron trajectory. The slice is cut along a direction perpendicular to the electron trajectory, and the thicknesses of multiple penetrating layers and multiple protruding layers are determined respectively. The number of penetrating layers and protruding layers is determined according to the length. A plurality of first foils are determined based on the thickness of the plurality of through layers, and a plurality of second foils are determined based on the thickness of the plurality of protruding layers; Through holes and positioning holes are respectively formed on multiple first foil materials to prepare multiple through layers; Multiple protruding layers are prepared by forming limiting through holes and positioning holes on multiple second foils, wherein a portion of the multiple protruding layers is designated as a first protruding layer and another portion of the multiple protruding layers is designated as a second protruding layer, and the limiting through holes are smaller than the through holes. The positioning element passes through the positioning holes in each of the through layers, each of the first protruding layers, and each of the second protruding layers, and alternates between every two through layers, the first protruding layers, and the second protruding layers, such that the first limiting through hole and the second limiting through hole overlap with the through hole on opposite sides of the through hole; and The contact surfaces between adjacent through layers and protruding layers are welded to form a slow-wave structure.

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