High-power double ribbon injection slow wave structure and electromagnetic wave output method

Abstract

The application discloses a high-power double-belt electron beam slow wave structure and an electromagnetic wave output method, and belongs to the technical field of electron beam devices. The high-power double-belt electron beam slow wave structure comprises two slow wave structures, wherein each slow wave structure comprises a first coupling cavity, a second coupling cavity, a plurality of gratings arranged between the first coupling cavity and the second coupling cavity, and an electron beam channel penetrating through the plurality of gratings; an inter-grating gap is arranged between adjacent two gratings and is communicated with the first coupling cavity and the second coupling cavity; the first coupling cavities of the two slow wave structures are communicated through at least one connecting cavity; and the second coupling cavities of the two slow wave structures are connected with an output structure for outputting electromagnetic waves. The connecting cavity is arranged between the two coupling cavities, the electric field of the two first coupling cavities is concentrated by the connecting cavity, the coupling efficiency of the connecting cavity is increased, the modulation depth of the electromagnetic wave to the electron beam is further improved, the electron beam exchanges more energy to the electromagnetic wave, and the output effect of the electromagnetic wave is improved.

Description

Technical Field

[0001] This invention relates to the field of vacuum electronic device technology, specifically to a high-power dual-strip injection slow-wave structure and an electromagnetic wave output method. Background Technology

[0002] Currently, the development potential of extended interactive oscillators (EIOs) in the terahertz band has made them one of the research hotspots for terahertz sources in recent years. Trapezoidal slow-wave structures are common EIO slow-wave structures, characterized by simple structure, high coupling impedance, and the ability to interact with strip beams. In order to improve the performance of trapezoidal slow-wave structures, a large amount of theoretical research, simulation calculations, and experiments have been carried out on trapezoidal structures in existing technologies.

[0003] When extended interaction devices operate in the terahertz band, the size of the trapezoidal slow-wave structure needs to be limited to the order of hundreds of micrometers. This not only presents significant manufacturing challenges but also results in limited output power due to the small power capacity of a single cavity. To improve output power without significantly increasing the size of the trapezoidal slow-wave structure, the inventors' team provided a four-strip-beam trapezoidal slow-wave structure in patent CN114899066B. This structure employs a design of four orthogonal electron beam channels interconnected by coupling cavities to increase the coupling efficiency of electromagnetic waves within the coupling cavities. Consequently, under relatively small size constraints, the output power is increased by more than five times compared to the traditional single-strip-beam trapezoidal slow-wave structure.

[0004] However, although the volume of this four-strip-beam trapezoidal slow-wave structure is smaller than the sum of the volumes of four traditional single-strip-beam trapezoidal slow-wave structures, its overall volume is still relatively large. Furthermore, it requires four strips of beams traveling at the same velocity to enhance the electromagnetic wave within the coupling cavity when outputting power, which limits its application to some extent. Simultaneously, the inventors discovered that using a grating with electron beam channels to connect two adjacent coupling cavities may affect the modulation depth during coupling. Therefore, it is necessary to optimize the existing four-strip-beam trapezoidal slow-wave structure to further improve its output efficiency within a smaller volume. Summary of the Invention

[0005] The purpose of this invention is to provide a high-power dual-strip-beam slow-wave structure, which utilizes a connecting cavity to connect the coupling cavities of two slow-wave structures, enabling the electric field coupling to mutually enhance each other, thereby achieving deeper modulation of the electron beam. The strip electron beam can exchange more energy with the electromagnetic wave, thus further improving the output efficiency of the slow-wave structure. In addition, this dual-strip-beam slow-wave structure only requires two strip beams with the same speed during use, and its overall volume is smaller, which is beneficial for broadening its applications.

[0006] This invention is achieved through the following technical solution:

[0007] A high-power dual-strip-beam slow-wave structure includes two slow-wave structures. Each slow-wave structure includes a first coupling cavity, a second coupling cavity, a plurality of gratings located between the first and second coupling cavities, and an electron beam channel penetrating the plurality of gratings. A grating gap communicating with the first and second coupling cavities is provided between two adjacent gratings. The first coupling cavities of the two slow-wave structures are connected through at least one connecting cavity. An output structure for outputting electromagnetic waves is connected to the second coupling cavities of the two slow-wave structures.

[0008] In this technical solution, the dual-strip injection slow-wave structure includes two slow-wave structures, each including a first and a second coupling cavity. A plurality of gratings are disposed between the first and second coupling cavities, and electron beam channels for the strip injection are formed on the gratings. In one or more embodiments, the structures and dimensions of the two slow-wave structures may be the same or different. Preferably, the structures and dimensions of the two slow-wave structures are the same.

[0009] There is a grating gap between two adjacent gratings, and the grating gap is connected to the first coupling cavity and the second coupling cavity, so that the electromagnetic signal excited by the electron beam through the grating can enter the first and second coupling cavities.

[0010] In this technical solution, one or more connecting cavities distributed along the extension direction of the electron beam channel are provided between the first coupling cavities of the two slow-wave structures. The two ends of the connecting cavity are connected to the two first coupling cavities through coupling holes, allowing electromagnetic waves in the first coupling cavities to enter the connecting cavity. By using the connecting cavity to concentrate the electric fields of the two first coupling cavities, the coupling efficiency of the electromagnetic waves can be effectively improved, thereby enabling the electromagnetic waves to modulate the electron beam more deeply, with a modulation depth of over 30%. The strip-shaped electron beam can then exchange more energy with the electromagnetic waves.

[0011] In this technical solution, an output structure is connected to the second coupling cavity of the two slow waves. The output power in the two second coupling cavities is fused using the output structure, and finally an electromagnetic wave with further enhanced power is output from the output structure.

[0012] In this technical solution, the output structure is connected to the second coupling cavity, and the connecting cavity is connected to the first coupling cavity. This allows the electromagnetic waves coupled in the connecting cavity to fully interact with the electron beam, thereby further improving the modulation depth of the electron beam.

[0013] During operation, two electron beams enter the electron beam channels of two slow-wave structures respectively. When the electron beams pass through the grating, they generate electromagnetic waves. These electromagnetic waves couple through the connecting cavity in the two first coupling cavities and interact with the electron beams through the frequency selection characteristics of the slow-wave circuit, modulating the velocity and density of the electron beams. During the velocity modulation of the electron beams by the high-frequency field, electrons in the positive half-cycle of the high-frequency field are decelerated to a speed lower than DC, while electrons in the negative half-cycle gain energy, increase their velocity, and exceed DC. Faster electrons tend to gravitate towards slower electrons, creating a clustering phenomenon. This results in most electrons being in the deceleration region, allowing the electron beams to transfer more energy to the high-frequency field, thereby outputting electromagnetic waves of a specific frequency from the output structure. Throughout the process, the modulation effect of the electron beams is enhanced due to the connecting cavity, thus strengthening the beam-wave interaction and ultimately increasing the output power.

[0014] Compared to existing technologies that use coupling cavities to increase the coupling efficiency of electromagnetic waves and thus improve the output power of electromagnetic waves, this application provides a connecting cavity between the two coupling cavities. By using the connecting cavity to connect the two first coupling cavities, the coupling efficiency of the first coupling cavity is increased, thereby improving the modulation depth of the electromagnetic wave on the electron beam. The electron beam exchanges more energy with the electromagnetic wave, improving the output effect of the electromagnetic wave. Moreover, the overall size of the entire device can be further reduced, and only two electron beams are needed to effectively improve the output power of the electromagnetic wave, which is conducive to expanding the application scenarios of the entire device.

[0015] In a preferred configuration of the connecting cavity in this invention, the width of the connecting cavity is smaller than the wavelength of the electromagnetic wave generated within the slow-wave structure. The width of the connecting cavity is the distance between the first coupling cavities of the two slow-wave structures. If the width of the connecting cavity is too long, it will affect the coupling effect of the electromagnetic wave. The width of the connecting cavity is designed based on the wavelength of the electromagnetic wave generated when the electron beam passes through the grating of the slow-wave structure. In this technical solution, the width of the connecting cavity is set to be smaller than the wavelength of the generated electromagnetic wave.

[0016] Furthermore, the length of the connecting cavity is N times the length of the grating gap P, where N is a positive integer. The length of the connecting cavity refers to its length along the extension direction of the electron beam channel. Simulation calculations show that the coupling effect of the connecting cavity is better when its length is N times the length of the grating gap P.

[0017] Further, the length of the grating gap is 0.1 to 1.0 mm. The length of the grating gap can be adjusted according to the operating frequency of the grating. Preferably, the length of the grating gap is 0.1 to 1.0 mm, and more preferably, the length of the grating gap is 0.2 to 0.7 mm.

[0018] Furthermore, the number of connecting cavities is 1 to 5, and the connecting cavities are evenly distributed along the extension direction of the electron beam channel. The number of connecting cavities can be one or more. In this technical solution, preferably, the number of connecting cavities does not exceed 5, and the connecting cavities are evenly distributed along the extension direction of the electron beam channel.

[0019] Furthermore, the central axis of at least one connecting cavity is collinear with the central axis of the first coupling cavity. In this technical solution, the central axis refers to the transverse central axis perpendicular to the electron beam extension direction. That is, when there are multiple connecting cavities, at least one connecting cavity is located in the middle of the first coupling cavity to further improve the coupling efficiency of electromagnetic waves.

[0020] Furthermore, the height of the electron injection channel is 5 to 10 times its width.

[0021] Furthermore, the width of the electron injection channel is 0.1–0.5 mm.

[0022] Furthermore, the output structure includes a coupling aperture connected to the second coupling cavity. The coupling aperture is connected to a curved waveguide via a transmission structure, and the curved waveguides connected to the two slow-wave structures are jointly connected to a rectangular waveguide. In this technical solution, the output power of the transmission structures of the two slow-wave structures is fused using a power fusion method and then output from a standard waveguide port, which can further improve the output power of the electromagnetic wave.

[0023] An electromagnetic wave output method, employing any of the aforementioned high-power dual-strip injection slow-wave structures, includes the following steps:

[0024] Two electron beams with the same velocity propagate along electron beam channels of two slow-wave structures. The electron beams generate electromagnetic waves as they pass through several gratings. The electromagnetic waves generated within the two slow-wave structures are coupled and enhanced within the two first coupling cavities through the connecting cavity. The electromagnetic waves then interact with the electron beams, ultimately radiating out from the output structure. In some preferred embodiments, cold-cavity simulation calculations show that the output power of the above structure and method is more than three times higher than that of a traditional single-strip-beam trapezoidal slow-wave structure.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0026] 1. The present invention provides a connecting cavity between two coupling cavities. By utilizing the connecting cavity to connect the two first coupling cavities, the coupling efficiency of the first coupling cavity is increased, thereby improving the modulation depth of the electromagnetic wave on the electron beam. Compared with the prior art, which uses a coupling cavity to increase the coupling efficiency of the electromagnetic wave and thus improve the output power of the electromagnetic wave, in the present invention, the electron beam exchanges more energy to the electromagnetic wave, thereby improving the output effect of the electromagnetic wave.

[0027] 2. The overall size of the present invention can be further reduced, and only two electron beams are needed to effectively improve the output power of electromagnetic waves, which is beneficial to expanding the application scenarios of the entire device;

[0028] 3. By setting the width of the connecting cavity to be smaller than the wavelength of the generated electromagnetic wave, and in particular, the width of the connecting cavity to be approximately equal to half the wavelength of the generated electromagnetic wave, the coupling efficiency of the connecting cavity can be further improved.

[0029] 4. By setting the length of the connecting cavity to a positive integer multiple, especially an odd multiple, of the grating gap, the present invention can further improve the coupling effect;

[0030] 5. Compared with the traditional single-strip trapezoidal slow-wave structure, the output power of this invention can be increased by more than 3 times. Attached Figure Description

[0031] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0032] Figure 1 This is a schematic diagram of the dual-strip slow-wave injection structure in a specific embodiment of the present invention;

[0033] Figure 2 This is a partial longitudinal cross-sectional view of the dual-strip slow-wave structure along the direction perpendicular to the propagation direction of the strip electron beam in a specific embodiment of the present invention;

[0034] Figure 3 This is a partial longitudinal cross-sectional view of the dual-strip slow-wave structure along the direction parallel to the propagation of the strip electron beam in a specific embodiment of the present invention;

[0035] Figure 4 In a specific embodiment of the present invention, it operates in TM. 31 Electron injection phase space diagram of a 0.14THz dual-strip injection slow-wave structure extended interaction oscillator with a -2π mode;

[0036] Figure 5 In a specific embodiment of the present invention, it operates in TM. 31 Output power of the 0.14THz dual-strip injection slow-wave structure in the -2π mode;

[0037] Figure 6 In a specific embodiment of the present invention, it operates in TM. 31 The spectrum of the output electromagnetic wave of a 0.14THz dual-strip injection slow-wave structure extended interaction oscillator with a -2π mode.

[0038] The attached diagram shows the markings and corresponding component names:

[0039] 1-First coupling cavity, 2-Second coupling cavity, 3-Grate, 4-Connecting cavity, 5-Coupled hole, 6-Transmission structure, 7-Curved waveguide, 8-Rectangular waveguide, 9-Electron beam, 10-Electron beam channel, 11-Grate gap. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0041] In the description of this invention, it should be understood that the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0042] Example 1:

[0043] like Figures 1 to 3 The high-power dual-strip-beam slow-wave structure shown includes two slow-wave structures. Each slow-wave structure includes a first coupling cavity 1, a second coupling cavity 2, a plurality of gratings 3 located between the first coupling cavity 1 and the second coupling cavity 2, and an electron beam channel 10 passing through the plurality of gratings 3. A grating gap 11 communicating with the first coupling cavity 1 and the second coupling cavity 2 is provided between two adjacent gratings 3. The first coupling cavities 1 of the two slow-wave structures are connected through at least one connecting cavity 4. An output structure for outputting electromagnetic waves is connected to the second coupling cavities 2 of the two slow-wave structures.

[0044] During operation, two electron beams enter the electron beam channels of two slow-wave structures respectively. When the electron beams pass through the grating, they generate electromagnetic waves. These electromagnetic waves are coupled in the two first coupling cavities through the connecting cavity and interact with the electron beams through the frequency selection characteristics of the slow-wave circuit. This modulates the velocity and density of the electron beams, allowing them to exchange more energy with the high-frequency field. As a result, electromagnetic waves of a specific frequency are output from the output structure. Throughout the process, the modulation effect of the electron beams is enhanced due to the connecting cavity, which in turn enhances the beam-wave interaction and ultimately increases the output power.

[0045] In this embodiment, compared with the prior art method of using a coupling cavity to increase the coupling efficiency of electromagnetic waves and thus improve the output power of electromagnetic waves, a connecting cavity is provided between the two coupling cavities in this application. The connecting cavity increases the coupling efficiency of the first coupling cavity by connecting the two first coupling cavities, thereby improving the modulation depth of the electromagnetic wave on the electron beam. The electron beam exchanges more energy to the electromagnetic wave, improving the output effect of the electromagnetic wave.

[0046] In one or more embodiments, the two slow-wave structures may have the same structure and different dimensions. Preferably, the two slow-wave structures have the same structure and dimensions.

[0047] In some embodiments, the length of the grating gap 11 is 0.1–1.0 mm. Preferably, the length of the grating gap is 0.2–0.7 mm.

[0048] In some embodiments, the height of the electron injection channel 10 is 5 to 10 times its width.

[0049] In one or more embodiments, the width of the electron injection channel 10 is 0.1 to 0.5 mm.

[0050] Example 2:

[0051] Based on Embodiment 1, the width of the connecting cavity 4 is smaller than the wavelength of the electromagnetic wave generated within the slow-wave structure. In one or more preferred embodiments, the width of the connecting cavity is approximately equal to half the wavelength of the generated electromagnetic wave.

[0052] In some preferred embodiments, the length of the connecting cavity 4 is N times the length of the grating gap 11, where N is a positive integer. In one or more preferred embodiments, the length of the connecting cavity is an odd multiple of the length of the grating gap P.

[0053] In some embodiments, the number of connecting cavities 4 is 1 to 5, and the connecting cavities 4 are evenly distributed along the extension direction of the electron injection channel 10.

[0054] In some embodiments, the central axis of at least one connecting cavity 4 is collinear with the central axis of the first coupling cavity 1.

[0055] Example 3:

[0056] Based on the above embodiments, such as Figure 1 As shown, the output structure includes a coupling hole 5 connected to the second coupling cavity 2. The coupling hole 5 is connected to a curved waveguide 7 via a transmission structure 6. The curved waveguides 7 connected to the two slow wave structures are connected to a rectangular waveguide 8.

[0057] By combining the output power of two slow-wave transmission structures using a power fusion method and then outputting it from a standard waveguide port, the output power of electromagnetic waves can be further improved.

[0058] Example 4:

[0059] An electromagnetic wave output method, employing a high-power dual-strip injection slow-wave structure from any of the foregoing embodiments, the method comprising the following steps:

[0060] Two electron beams 9 with the same speed are transmitted along two slow-wave structure electron beam channels 10 respectively. When the electron beams 9 pass through several gratings 3, they generate electromagnetic waves.

[0061] The electromagnetic waves excited in the two slow-wave structures are coupled and enhanced in the two first coupling cavities 1 through the connecting cavity 4. The electromagnetic waves interact with the electron beam 9 and are finally radiated out from the output structure.

[0062] Example 5:

[0063] Calculations are performed using CST software on TM. 31 A 0.14THz extended interactive oscillator with a -2π mode and a dual-strip-beam slow-wave structure, wherein the dimensions of the dual-strip-beam slow-wave structure are:

[0064]

[0065] Simulation results are as follows Figures 4 to 6 As shown. Figure 4 The phase space diagram is shown in the figure. The modulation depth of the electron beam is 36.5%, which results in better beam-wave interaction.

[0066] like Figure 5 As shown, the output power of the dual-strip-beam slow-wave structure is 1512W, which is 3.11 times higher than the output power of the single-strip-beam slow-wave structure of 485W. This proves that the method of connecting two first coupling cavities using a connecting cavity, as disclosed in this invention, can further improve the coupling efficiency of electromagnetic waves and increase the output power in a smaller volume, thus better meeting the needs of extended interaction devices operating in the terahertz band.

[0067] The output spectrum of the dual-band slow-wave structure is as follows: Figure 6 As shown, the frequency is consistent with the cold cavity analysis.

[0068] The terms "first," "second," etc., used in this invention (e.g., first coupling cavity, second coupling cavity, etc.) are merely for clarity of description and are not intended to limit any order or emphasize importance. Furthermore, the term "connection" used in this invention, unless otherwise specified, can refer to a direct connection or an indirect connection via other components.

[0069] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-power dual-strip injection slow-wave structure, characterized in that, The device includes two slow-wave structures, each comprising a first coupling cavity (1), a second coupling cavity (2), a plurality of gratings (3) located between the first coupling cavity (1) and the second coupling cavity (2), and an electron beam channel (10) passing through the plurality of gratings (3). A grating gap (11) communicating with the first coupling cavity (1) and the second coupling cavity (2) is provided between two adjacent gratings (3). The first coupling cavities (1) of the two slow-wave structures are connected through at least one connecting cavity (4). An output structure for outputting electromagnetic waves is connected to the second coupling cavities (2) of the two slow-wave structures. The central axis of at least one connecting cavity (4) is collinear with the central axis of the first coupling cavity (1); The output structure includes a coupling hole (5) connected to the second coupling cavity (2), and the coupling hole (5) is connected to a curved waveguide (7) via a transmission structure (6). The curved waveguides (7) connected to the two slow wave structures are connected to a rectangular waveguide (8).

2. The high-power dual-strip injection slow-wave structure according to claim 1, characterized in that, The width of the connecting cavity (4) is smaller than the wavelength of the electromagnetic wave generated in the slow wave structure.

3. The high-power dual-strip injection slow-wave structure according to claim 1, characterized in that, The length of the connecting cavity (4) is N times the grating gap (11), where N is a positive integer.

4. A high-power dual-strip injection slow-wave structure according to claim 3, characterized in that, The length of the grating gap (11) is 0.1~1.0 mm.

5. A high-power dual-strip injection slow-wave structure according to claim 1, characterized in that, The number of the connecting cavities (4) is 1 to 5, and the connecting cavities (4) are evenly distributed along the extension direction of the electron injection channel (10).

6. A high-power dual-strip injection slow-wave structure according to claim 1, characterized in that, The height of the electron injection channel (10) is 5 to 10 times its width.

7. A high-power dual-strip injection slow-wave structure according to claim 6, characterized in that, The width of the electron injection channel (10) is 0.1~0.5 mm.

8. A method for outputting electromagnetic waves, characterized in that, The method employing the high-power dual-strip injection slow-wave structure according to any one of claims 1 to 7 includes the following steps: Two electron beams (9) with the same speed are transmitted along two slow-wave structure electron beam channels (10) respectively. When the electron beams (9) pass through several gratings (3), they generate electromagnetic waves. The electromagnetic waves excited in the two slow-wave structures are coupled and enhanced in the two first coupling cavities (1) through the connecting cavity (4). The electromagnetic waves interact with the electron beam (9) and are finally radiated out from the output structure.

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