Overmoded slow wave structure and traveling wave tube

Abstract

The application relates to an overmoded slow wave structure and a traveling wave tube. The overmoded slow wave structure comprises a first periodic waveguide and a second periodic waveguide arranged oppositely; the end faces of the first periodic waveguide and the second periodic waveguide arranged oppositely in a first direction are respectively end faces with periodic changes in fluctuation; a wave valley part of the first periodic waveguide is provided with a first opening and a second opening, a wave crest part of the second periodic waveguide is provided with a third opening and a fourth opening, the first opening and the third opening are arranged oppositely, each first opening and each third opening are communicated in the first direction to form a first strip-shaped electron beam channel; the second opening and the fourth opening are arranged oppositely, each second opening and each fourth opening are communicated in the first direction to form a second strip-shaped electron beam channel. The overmoded slow wave structure can improve the device performance of the traveling wave tube.

Description

Technical Field

[0001] This application relates to the field of vacuum electronic device technology, and in particular to an overmode slow-wave structure and a traveling wave tube. Background Technology

[0002] Terahertz waves are electromagnetic waves with frequencies ranging from 0.1 THz to 10 THz and wavelengths ranging from approximately 0.03 to 3 mm, falling between microwaves and infrared. Terahertz technology has broad application prospects in fields such as medicine, security inspection, and communications. However, the widespread application of terahertz waves is limited by the generation of terahertz sources.

[0003] A traveling wave tube (TWT) is a common vacuum electronic device. In a TWT, a high-speed electron beam passes through a series of magnetic fields and a slow-wave structure to generate terahertz radiation. The slow-wave structure, as the core component of the TWT, directly determines its performance. Summary of the Invention

[0004] Therefore, it is necessary to provide an over-mode slow-wave structure and a traveling wave tube to address the aforementioned technical problems, thereby improving the device performance of the traveling wave tube.

[0005] An overmode slow wave structure, the overmode slow wave structure comprising: a first periodic waveguide and a second periodic waveguide disposed opposite to each other;

[0006] In the first direction, the end faces of the first periodic waveguide and the second periodic waveguide disposed opposite to each other are end faces with periodic fluctuations.

[0007] The first periodic waveguide has a first opening and a second opening at its trough, and the second periodic waveguide has a third opening and a fourth opening at its crest. The first opening and the third opening are arranged opposite to each other, and each of the first openings and each of the third openings are connected in the first direction to form a first strip-shaped electron beam channel. The second opening and the fourth opening are arranged opposite to each other, and each of the second openings and each of the fourth openings are connected in the first direction to form a second strip-shaped electron beam channel.

[0008] In one embodiment, the waveguide wide side length of the overmode slow wave structure along the second direction is greater than twice the waveguide narrow side length of the overmode slow wave structure along the third direction, wherein the first direction, the second direction, and the third direction intersect each other.

[0009] In one embodiment, the end face of the first periodic waveguide has the same shape, the same wave amplitude, and the same wave period as the end face of the second periodic waveguide.

[0010] In one embodiment, the first periodic waveguide and the second periodic waveguide are both sinusoidal waveguides.

[0011] In one embodiment, the spacing between the first periodic waveguide and the second periodic waveguide is the difference between the narrow side length of the waveguide and the height of twice the sinusoidal periodic undulation of the first periodic waveguide and the second periodic waveguide.

[0012] In one embodiment, the spacing between the first strip electron beam channel and the second strip electron beam channel in the second direction is less than half the length of the wide side of the waveguide.

[0013] In one embodiment, the waveguide wide side length of the overmode slow wave structure along the second direction is a, and the waveguide narrow side length of the overmode slow wave structure along the third direction is b, where a = 3.5 mm and b = 1.55 mm, and the first direction, the second direction and the third direction intersect each other.

[0014] In one embodiment, the period lengths of the sinusoidal periodic undulations of the first periodic waveguide and the second periodic waveguide are p, the heights of the sinusoidal periodic undulations of the first periodic waveguide and the second periodic waveguide are h, and the spacing between the first periodic waveguide and the second periodic waveguide is hb, where p = 1.45 mm, h = 0.6 mm, and hb = 0.35 mm.

[0015] In one embodiment, the distance between the first and second strip electron beam channels in the second direction is m, the width of the first and second strip electron beam channels in the second direction is t, and the width of the first and second strip electron beam channels in the third direction is s, where m = 1.45 mm, t = 0.3 mm, and s = 1.0 mm, and the first, second, and third directions intersect each other.

[0016] A traveling wave tube comprising the overmode slow wave structure described in any of the above embodiments.

[0017] The aforementioned overmode slow-wave structure includes a first periodic waveguide and a second periodic waveguide arranged opposite to each other, with the opposite end faces of the first periodic waveguide and the second periodic waveguide having periodically changing undulating end faces. By setting the opposite end faces of the first periodic waveguide and the second periodic waveguide to have periodically changing undulating end faces, the conductivity loss of the slow-wave structure can be reduced and it is easier to process. By forming a first strip-shaped electron beam channel and a second strip-shaped electron beam channel between the first periodic waveguide and the second periodic waveguide, the number of electron beam channels is increased while the lateral dimension of the overmode slow-wave structure is increased, enabling the overmode slow-wave structure of this application to provide a larger operating current and improve the interaction coupling impedance, thereby improving the output performance of the traveling wave tube device. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a three-dimensional structural schematic diagram of the overmode slow wave structure in one embodiment of this application;

[0020] Figure 2 for Figure 1 Left view of an intermediate-mode slow-wave structure;

[0021] Figure 3 for Figure 1 Front view of a mid-mode slow-wave structure;

[0022] Figure 4 for Figure 1 A schematic diagram of the three-dimensional structure of the intermediate-mode slow-wave structure after electron injection;

[0023] Figure 5 for Figure 1 A schematic diagram showing the relationship between normalized phase velocity and frequency in an overmode slow-wave structure;

[0024] Figure 6 for Figure 1 A schematic diagram showing the relationship between coupling impedance and frequency for an overmode slow-wave structure.

[0025] Explanation of reference numerals in the attached figures: 11-first periodic waveguide, 111-first opening, 112-second opening, 12-second periodic waveguide, 121-third opening, 122-fourth opening, 21-first strip-shaped electron beam channel, 22-second strip-shaped electron beam channel, 31-first electron beam, 32-second electron beam. Detailed Implementation

[0026] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0028] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.

[0029] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0030] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediary element. Furthermore, in the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if there is transmission of electrical signals or data between the connected objects.

[0031] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” or “having,” etc., specify the presence of the stated feature, whole, step, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.

[0032] Terahertz waves refer to electromagnetic waves with frequencies ranging from 0.1 THz to 10 THz and wavelengths ranging from approximately 0.03 to 3 mm, falling between microwaves and infrared. The development of terahertz technology focuses on three main areas: terahertz time-domain spectroscopy, terahertz imaging, and terahertz communication. Terahertz time-domain spectroscopy utilizes the transient and coherent nature of terahertz pulses for spectral measurements. In measuring oil-bearing reservoir rocks, it can be used to analyze physical properties such as porosity and permeability, providing crucial information for oil and gas extraction. Furthermore, the high signal-to-noise ratio and non-destructive nature of terahertz spectrometers give them advantages in the identification and detection of hazardous chemicals such as explosives. Terahertz imaging utilizes the characteristics of terahertz waves for high-resolution and high-sensitivity imaging. In the medical field, terahertz imaging can acquire high-resolution and high-contrast images, aiding doctors in the early detection and diagnosis of tumors. In security inspection, it can be used to identify concealed metallic and non-metallic objects. Terahertz communication technology utilizes the high-frequency and wideband characteristics of terahertz waves for high-speed data transmission. Compared to traditional radio communication, terahertz communication offers higher spectral bandwidth and data transmission rates. Furthermore, due to the short wavelength and high-frequency characteristics of terahertz waves, terahertz communication systems exhibit superior interference immunity and lower bit error rate performance. In the field of wireless communication, terahertz communication technology can be used for high-speed data transmission and broadband wireless access. Additionally, in satellite communication, terahertz communication technology can be used for applications such as high-resolution image transmission and real-time data transmission.

[0033] The widespread application of terahertz waves is currently limited by the generation of terahertz sources. How to generate broadband, high-power terahertz sources is a thorny problem facing the industry. There are two ways to generate terahertz sources: one is through semiconductor devices, i.e., solid-state methods; the other is through vacuum electronic devices. Vacuum electronic devices generate terahertz radiation using electron beams. Traveling wave tubes (TWTs) are a common type of vacuum electronic device. In a TWT, a high-speed electron beam passes through a series of magnetic fields and slow-wave structures to generate terahertz radiation. The slow-wave structure, as the core component of the TWT, directly determines its device performance.

[0034] To improve the device performance of the traveling wave tube, in one embodiment, such as Figure 1 As shown, this application provides an overmode slow wave structure, which includes: a first periodic waveguide 11 and a second periodic waveguide 12 arranged opposite to each other.

[0035] In the first direction, the end faces of the first periodic waveguide 11 and the second periodic waveguide 12, which are arranged opposite each other, are end faces with periodic fluctuations. The first periodic waveguide 11 has a first opening 111 and a second opening 112 at its trough, and the second periodic waveguide 12 has a third opening 121 and a fourth opening 122 at its crest. The first opening 111 and the third opening 121 are arranged opposite each other, and each first opening 111 and each third opening 121 are connected in the first direction to form a first strip-shaped electron beam channel 21. The second opening 112 and the fourth opening 122 are arranged opposite each other, and each second opening 112 and each fourth opening 122 are connected in the first direction to form a second strip-shaped electron beam channel 22.

[0036] like Figure 2 As shown, in the first direction, i.e., the X-axis direction, the end faces of the first periodic waveguide 11 and the second periodic waveguide 12, which are disposed opposite to each other, are end faces with periodically changing undulating ripples. Optionally, the end face with periodically changing undulating ripples includes at least one of a sine wave end face, a triangular wave end face, and a square wave end face. Preferably, the end face with periodically changing undulating ripples is a sine wave end face.

[0037] Combination Figures 1 to 4 As shown, the first periodic waveguide 11 has first openings 111 and second openings 112 at each trough, and the second periodic waveguide 12 has third openings 121 and fourth openings 122 at each peak. It can be understood that the projections of the first openings 111 and the third openings 121 in the ZY plane coincide, so that the first openings 111 and the third openings 121 can connect in the first direction to form a first strip-shaped electron beam channel 21; the projections of the second openings 112 and the fourth openings 122 in the ZY plane coincide, so that the second openings 112 and the fourth openings 122 can connect in the first direction to form a second strip-shaped electron beam channel 22. In application, a first electron beam 31 can be placed in the first strip-shaped electron beam channel 21, and a second electron beam 32 can be placed in the second strip-shaped electron beam channel 22.

[0038] In related technologies, a slow-wave structure includes two parallel metal plates and two sidewalls perpendicular to and opposite to the metal plates. The sidewalls can be metal walls or dielectric walls. The two metal plates and the two sidewalls together form a cuboid. The distance between the vertically opposite metal plates of the cuboid is the narrow side of the waveguide, and the distance between the front and rear opposite sidewalls of the cuboid is the wide side of the waveguide.

[0039] In this application, the overmode slow wave structure includes a first periodic waveguide 11 and a second periodic waveguide 12 arranged opposite to each other. The first periodic waveguide 11 has a first opening 111 and a second opening 112 at each trough, and the second periodic waveguide 12 has a third opening 121 and a fourth opening 122 at each peak. The first opening 111 and the third opening 121 are connected in a first direction to form a first strip-shaped electron beam channel 21, and the second opening 112 and the fourth opening 122 are connected in a first direction to form a second strip-shaped electron beam channel 22. Therefore, the overmode slow wave structure in this embodiment forms multiple electron beam channels, and the electron beam channels in this embodiment are strip-shaped electron beam channels. Compared to the circular electron beam channels in related technologies, the cross-sectional area of ​​the strip-shaped electron beam channel is larger than that of the circular electron beam channel at the same current density. Therefore, the strip-shaped electron beam channel can increase the lateral dimension of the electron beam, thereby providing a larger operating current, and thus improving the output power, gain, and interaction efficiency of the traveling wave tube. In this application, the first direction is the X-axis direction, the second direction is the Y-axis direction, and the third direction is the Z-axis direction.

[0040] Furthermore, as the operating frequency of traveling wave tubes (TWTs) increases towards terahertz, problems inevitably arise such as reduced slow-wave structure size, increased fabrication difficulty, and decreased output power. Conventional fundamental-mode TWTs, due to their narrow electron beam channels and limited electron flow, struggle to achieve high-current operation. The overmode slow-wave structure of this application increases the lateral dimension of the slow-wave structure, effectively reducing fabrication difficulty. Simultaneously, by increasing the electron beam channel size, a larger operating current can be provided, thereby effectively improving the TWT's output power, gain, and other performance indicators. Moreover, the overmode slow-wave structure of this application includes multiple electron beam channels, ensuring that two or more electron beams interact with the electromagnetic wave independently. The increased total current enhances the output power of the overmode TWT.

[0041] The aforementioned overmode slow-wave structure includes a first periodic waveguide and a second periodic waveguide arranged opposite to each other, and the end faces of the first periodic waveguide and the second periodic waveguide are respectively end faces with periodic fluctuations. By setting the end faces of the first periodic waveguide and the second periodic waveguide to be periodic fluctuations, the conductivity loss of the slow-wave structure can be reduced and it is easier to process. By forming a first strip-shaped electron beam channel and a second strip-shaped electron beam channel between the first periodic waveguide and the second periodic waveguide, the number of electron beam channels is increased while the lateral dimension of the overmode slow-wave structure is increased, so that the overmode slow-wave structure of this application can provide a larger operating current, thereby improving the output performance of the traveling wave tube device.

[0042] In one embodiment, such as Figure 3As shown, the waveguide wide side length of the overmode slow wave structure along the second direction is more than twice the waveguide narrow side length of the overmode slow wave structure along the third direction, wherein the first direction, the second direction and the third direction intersect each other.

[0043] It is understood that a slow-wave structure includes two parallel metal plates and two sidewalls perpendicular to and opposite to the metal plates. The sidewalls can be metal walls or dielectric walls. The two metal plates and the two sidewalls together form a cuboid. The distance between the vertically opposite metal plates of this cuboid is the narrow side b, and the distance between the front and rear opposite sidewalls of this cuboid is the wide side a. In order to reduce the size of the slow-wave structure, the length of the wide side a of the slow-wave structure operating in the fundamental mode is usually less than twice that of the narrow side b. As the operating frequency increases, the size of the fundamental mode slow-wave structure becomes smaller and smaller, the beam-wave interaction area decreases, and the output power gradually decreases. In this application, since the overmode slow-wave structure has a larger lateral dimension at the same frequency, it is more suitable for operating in the terahertz band (operating frequency greater than or equal to 100 GHz). Therefore, in the overmode slow-wave structure of this application, the waveguide wide side length a along the second direction is greater than twice the waveguide narrow side length b along the third direction, i.e., a > 2b. Although both the conventional fundamental mode structure and the overmode structure in this application can operate at high and low frequencies, when both operate at the same frequency, the overmode structure has a larger lateral dimension than the conventional fundamental mode structure—that is, the waveguide wide side length 'a' is larger than the waveguide wide side length of the conventional fundamental mode structure. This results in a larger interaction area for the overmode structure, which increases the input DC energy. By setting the waveguide wide side length 'a' to be more than twice the waveguide narrow side length 'b', the overmode slow-wave structure of this application can adapt to higher operating frequencies, maintaining good performance even at operating frequencies above 100 GHz. Preferably, the waveguide wide side length 'a' along the second direction is 3.5 mm, and the waveguide narrow side length 'b' along the third direction is 1.55 mm.

[0044] In one embodiment, such as Figure 1 and Figure 2 As shown, the end faces of the first periodic waveguide 11 and the second periodic waveguide 12 have the same shape, wave amplitude, and wave period. The end faces of the first periodic waveguide 11 and the second periodic waveguide 12 are of the same shape; for example, both are sinusoidal, triangular, or square wave end faces. Since the wave amplitude and wave period are the same for the end faces of the first periodic waveguide 11 and the second periodic waveguide 12, the crests and troughs of the sinusoids in the first periodic waveguide 11 and the second periodic waveguide 12 are on the same vertical line, facilitating fabrication.

[0045] In one embodiment, the first periodic waveguide and the second periodic waveguide are sinusoidal waveguides, respectively.

[0046] It is understandable that sinusoidal waveguides have the following advantages: low transmission loss, low reflection, and electromagnetic transmission characteristics superior to general metallic slow-wave structures; they can generate broadband high-power electromagnetic waves when combined with strip electron beams; and they are relatively easy to manufacture. However, the electric field strength in the direction of electromagnetic wave propagation of conventional sinusoidal waveguide slow-wave structures is relatively weak, resulting in a smaller coupling impedance. This leads to drawbacks such as lower output power and gain, and lower interaction efficiency in sinusoidal waveguide traveling wave tubes.

[0047] In this application, by opening a first opening 111 and a second opening 112 at each trough of the first periodic waveguide 11, and opening a third opening 121 and a fourth opening 122 at each peak of the second periodic waveguide 12, two strip-shaped electron beam channels are formed between the first periodic waveguide 11 and the second periodic waveguide. Therefore, the overmode slow-wave structure of this application is a multi-electron beam channel structure, and the electron beam channels are strip-shaped structures. Therefore, compared with conventional fundamental mode structures, it can provide a larger operating current and improve the interaction coupling impedance compared with conventional overmode structures. This overcomes the problem that the coupling impedance of conventional sinusoidal waveguide slow-wave structures is not large enough and the electric field strength is weak. This can increase the input operating current, enhance the longitudinal electric field, improve the beam-wave interaction efficiency, and ultimately improve the output power level and gain interaction efficiency of the device.

[0048] In one embodiment, the heights of the sinusoidal periodic undulations of the first periodic waveguide 11 and the second periodic waveguide 12 are h, respectively, and the distance between the first periodic waveguide 11 and the second periodic waveguide 12 is hb, wherein the distance between the first periodic waveguide 11 and the second periodic waveguide 12 is the difference between the narrow side length b of the waveguide and twice the height h of the sinusoidal periodic undulation.

[0049] like Figure 2 and Figure 3 As shown, the height of the sinusoidal periodic undulations of the first periodic waveguide 11 and the second periodic waveguide 12 is h. The distance between the upper and lower sinusoidal waveguide ridges, i.e., the distance between the first periodic waveguide 11 and the second periodic waveguide 12, is hb. The period length of the sinusoidal periodic undulations of the first periodic waveguide 11 and the second periodic waveguide 12 is p. In applications, when designing overmode slow-wave structures, the distance hb between the first periodic waveguide 11 and the second periodic waveguide 12 can be designed as the difference between the narrow side length b of the waveguide and twice the height h of the sinusoidal periodic undulations, i.e., hb = b - 2h. In applications, hb can be a negative number. Preferably, b = 1.55 mm, p = 1.45 mm, h = 0.6 mm, and hb = 0.35 mm.

[0050] In one embodiment, the widths of the first strip electron beam channel 21 and the second strip electron beam channel 22 in the third direction are s, the distance between the first strip electron beam channel 21 and the second strip electron beam channel 22 in the second direction is m, the width of the first strip electron beam channel 21 and the second strip electron beam channel 22 in the second direction is t, the horizontal distance between the first strip electron beam channel 21 and the sidewall closest to the first strip electron beam channel 21 is n, and the horizontal distance between the second strip electron beam channel 22 and the sidewall closest to the second strip electron beam channel 22 is also n. Wherein, the distance m between the first strip electron beam channel 21 and the second strip electron beam channel 22 in the second direction is less than half the waveguide width length a and greater than the horizontal distance n between the strip electron beam channel and the sidewall closest to the strip electron beam channel, i.e., n < m < a / 2. Preferably, s = 1.0 mm, t = 0.3 mm, m = 1.45 mm, and n = 0.725 mm.

[0051] In one example, the number of strip electron beam channels in this application is not limited to two. By increasing the waveguide width length 'a' along the second direction in the overmode slow wave structure, while keeping the spacing 'm' between the two strip electron beam channels in the second direction, more strip electron beam channels can be set in the overmode slow wave structure. This further enables the overmode slow wave structure of this application to provide a larger operating current and improve the interaction coupling impedance, thereby improving the output power, gain, and interaction efficiency of the traveling wave tube.

[0052] Based on the foregoing embodiments, such as Figures 1 to 4 As shown, in one embodiment, the overmode slow wave structure includes a first periodic waveguide 11 and a second periodic waveguide 12 arranged opposite to each other. The first periodic waveguide 11 has first openings 111 and second openings 112 at each trough, and the second periodic waveguide 12 has third openings 121 and fourth openings 122 at each peak. The first openings 111 and third openings 121 are connected in a first direction to form a first strip-shaped electron beam channel 21, and the second openings 112 and fourth openings 122 are connected in the first direction to form a second strip-shaped electron beam channel 22. The cross-sectional width of the electron beam channel is smaller than the width of the periodic waveguide. A first electron beam 31 can be disposed within the first strip-shaped electron beam channel 21, and a second electron beam 32 can be disposed within the second strip-shaped electron beam channel 22.

[0053] In the overmode slow wave structure, the length of the wide side of the waveguide along the second direction is a, the length of the narrow side of the waveguide along the third direction is b, the height of the periodic undulations of the sinusoidal lines of the first periodic waveguide 11 and the second periodic waveguide 12 is h, the period length of the periodic undulations of the sinusoidal lines of the first periodic waveguide 11 and the second periodic waveguide 12 is p, the distance between the first periodic waveguide 11 and the second periodic waveguide 12 is hb, the widths of the first strip electron beam channel 21 and the second strip electron beam channel 22 in the third direction are s, the distance between the first strip electron beam channel 21 and the second strip electron beam channel 22 in the second direction is m, the width of the first strip electron beam channel 21 and the second strip electron beam channel 22 in the second direction is t, the horizontal distance between the first strip electron beam channel 21 and the sidewall closest to the first strip electron beam channel 21 is n, and the horizontal distance between the second strip electron beam channel 22 and the sidewall closest to the second strip electron beam channel 22 is also n. a=3.5mm, b=1.55mm, p=1.45mm, h=0.6mm, s=1.0mm, t=0.3mm, m=1.45mm, n=0.725mm, hb=0.35mm.

[0054] Using the 3D electromagnetic simulation software HFSS, the dispersion characteristics of the overmode slow-wave structure can be calculated as follows: Figure 5 As shown, the coupling impedance of the electron beam channel in the overmode slow-wave structure can be expressed as follows: Figure 6 As shown, the results indicate that the slow-wave structure of this embodiment has a wide operating bandwidth, approximately 90 GHz to 105 GHz. In one example, although the coupling impedance of the first electron beam 31 and the second electron beam 32 is 0.8 ohms at the operating frequency of 95 GHz, the total coupling impedance of the first electron beam 31 and the second electron beam 32 is not simply the sum of two 0.8 ohms.

[0055] Based on the same inventive concept, this application also provides a traveling wave tube, including the overmode slow wave structure in any of the above embodiments.

[0056] In this embodiment, the slow wave structure of the traveling wave tube is an overmode slow wave structure as described in any of the above schemes. Since the overmode slow wave structure includes multiple electron beam channels and the electron beam channels are strip-shaped electron beam channels, it can provide a larger operating current and improve the interaction coupling impedance, thereby improving the output power, gain and interaction efficiency of the traveling wave tube. The traveling wave tube in this embodiment has high output performance.

[0057] In the description of this specification, references to terms such as "some embodiments," "other embodiments," and "ideal embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0058] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0059] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A slow-wave overmode structure, characterized in that, include: The first and second periodic waveguides are set up relative to each other; In the first direction, the end faces of the first periodic waveguide and the second periodic waveguide disposed opposite to each other are end faces with periodic fluctuations. The first periodic waveguide has a first opening and a second opening at its trough, and the second periodic waveguide has a third opening and a fourth opening at its peak. The first opening and the third opening are arranged opposite to each other, and each of the first openings and each of the third openings are connected in the first direction to form a first strip-shaped electron beam channel. The second opening is disposed opposite to the fourth opening, and each of the second openings and each of the fourth openings communicates in the first direction to form a second strip-shaped electron injection channel; The waveguide wide side length of the overmode slow wave structure along the second direction is greater than twice the waveguide narrow side length of the overmode slow wave structure along the third direction, wherein the first direction, the second direction and the third direction intersect each other; The spacing between the first periodic waveguide and the second periodic waveguide is the difference between the narrow side length of the waveguide and the height of twice the periodic undulation of the sinusoidal ripples of the first periodic waveguide and the second periodic waveguide.

2. The overmode slow-wave structure according to claim 1, characterized in that, The end face of the first periodic waveguide has the same shape, wave amplitude, and wave period as the end face of the second periodic waveguide.

3. The overmode slow-wave structure according to claim 1, characterized in that, The first periodic waveguide and the second periodic waveguide are both sinusoidal waveguides.

4. The overmode slow-wave structure according to claim 1, characterized in that, The spacing between the first and second strip electron beam channels in the second direction is less than half the length of the wide side of the waveguide.

5. The overmode slow-wave structure according to claim 1, characterized in that, The waveguide wide side length of the overmode slow wave structure along the second direction is a, and the waveguide narrow side length of the overmode slow wave structure along the third direction is b, where a = 3.5 mm and b = 1.55 mm, and the first direction, the second direction and the third direction intersect each other.

6. The overmode slow-wave structure according to claim 1, characterized in that, The period lengths of the sinusoidal periodic undulations of the first periodic waveguide and the second periodic waveguide are p, the heights of the sinusoidal periodic undulations of the first periodic waveguide and the second periodic waveguide are h, and the distance between the first periodic waveguide and the second periodic waveguide is hb, where p = 1.45 mm, h = 0.6 mm, and hb = 0.35 mm.

7. The overmode slow-wave structure according to claim 1, characterized in that, The distance between the first and second strip-shaped electron beam channels in the second direction is m, the width of the first and second strip-shaped electron beam channels in the second direction is t, and the width of the first and second strip-shaped electron beam channels in the third direction is s, where m = 1.45 mm, t = 0.3 mm, and s = 1.0 mm. The first direction, the second direction, and the third direction intersect each other.

8. A traveling wave tube, characterized in that, Includes the overmode slow wave structure as described in any one of claims 1 to 7.

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