Slow wave structure, traveling wave tube and communication equipment

Abstract

A slow wave structure, a traveling wave tube and a communication device relate to the technical field of vacuum electronic devices, the slow wave structure comprising: a conductive housing (11) having a vacuum shielding cavity (11a) inside; the plane zigzag slow wave line (12) is located in the vacuum shielding cavity (11a), and the plane zigzag slow wave line (12) is a periodically folded metal strip line which is located in the same plane and extends in the transmission direction (z) of an electron beam; the insulating structural member is used for fixedly suspending the plane zigzag slow wave line (12) in the vacuum shielding cavity (11a); and the metal ridge sheet (14) is convexly arranged on at least one inner surface, opposite to the plane zigzag slow wave line (12), of the conductive shell (11). The dispersion intensity of the slow wave structure can be weakened, the working bandwidth of the traveling wave tube is remarkably improved, and the working voltage of the traveling wave tube is effectively reduced.

Description

Slow-wave structure, traveling wave tube and communication equipment Technical Field

[0001] The present application relates to the technical field of vacuum electronic devices, and in particular to a slow-wave structure, a traveling wave tube, and a communication device. Background Art

[0002] The fifth generation (5G) communication network significantly increases the carrier frequency of communication by utilizing millimeter waves and even submillimeter waves, thereby achieving a wide frequency band that is dozens of times larger than the frequency band of the fourth generation (4G) communication network. This is also the fundamental reason for 5G's gain. However, as the wavelength decreases, the path loss of millimeter waves in free space is greater, and characteristics such as air attenuation and rain attenuation are not as good as those of low-frequency bands, which seriously affects the coverage of millimeter waves. Using a traveling-wave tube (TWT) as the final amplifier can greatly increase the transmission power, thereby significantly increasing the communication distance. It has become a focus of research and discussion among standards organizations and all parties in the industry chain.

[0003] The slow-wave structure (SWS) is used to reduce the phase velocity of electromagnetic waves to approximately the same speed as electrons, allowing for sufficient energy exchange between electrons and electromagnetic waves, achieving signal amplification. As a core component of a traveling wave tube (TWT), the quality of the SWS directly determines the technical excellence of the TWT.

[0004] The slow-wave structure, which uses dielectric rods to support a metal slow-wave line, is a common planar strip slow-wave structure. This structure, an improvement on the microstrip slow-wave structure, significantly reduces charge accumulation in the dielectric and can accommodate dual electron beams simultaneously, resulting in lower current density and reduced cathode load. However, this type of slow-wave structure exhibits strong dispersion characteristics, which also means that traveling wave tubes employing this structure have higher operating voltages and narrower operating bandwidths. This hinders the current application of low-voltage traveling wave tubes and cannot meet the requirements for amplifying broadband millimeter-wave signals in 5G communication networks.

[0005] Summary of the Invention

[0006] The present application provides a slow-wave structure, a traveling wave tube, and a communication device, which can reduce the dispersion intensity of the slow-wave structure, significantly improve the operating bandwidth of the traveling wave tube, and effectively reduce the operating voltage of the traveling wave tube.

[0007] In the first aspect, a slow-wave structure is provided, comprising: a conductive shell having a vacuum shielding cavity inside; a plane zigzag slow-wave line located in the vacuum shielding cavity, wherein the plane zigzag slow-wave line is a periodically folded metal strip line located in the same plane and extending along the transmission direction of the electron beam; an insulating structural member for fixing and suspending the plane zigzag slow-wave line in the vacuum shielding cavity; and a metal ridge protruding from at least one inner surface of the conductive shell opposite to the plane zigzag slow-wave line.

[0008] According to the slow-wave structure provided in the embodiment of the present application, a metal ridge is provided on the inner surface of the conductive shell, so that the size of the vacuum shielding cavity in the thickness direction is reduced. At this time, the electric field in the thickness direction (i.e., the axial direction) is compressed, and the axial electric field strength is enhanced. In addition, since the plane meandering slow-wave line is closer to the waveguide wall, the coupling capacitance is increased, thereby effectively reducing the dispersion intensity of the slow-wave structure and significantly improving the working bandwidth of the traveling wave tube. At the same time, it can effectively reduce the operating voltage and improve the efficiency of the traveling wave tube.

[0009] Simulation results also show that, compared to traditional slow-wave structures, the slow-wave structure provided by the embodiments of the present application has a flatter dispersion curve, enabling the electron beam to synchronize with electromagnetic waves over a wider frequency band. Furthermore, the interaction strength between the electromagnetic waves and the electron beam at each frequency point is essentially the same, thus enabling a traveling wave tube (TWT) with this structure to have a wider operating bandwidth and thus achieve broadband TWT design. Furthermore, simulation results also show that the slow-wave structure provided by the embodiments of the present application has a lower normalized phase velocity than traditional slow-wave structures, resulting in a TWT with this structure having a lower operating voltage.

[0010] Optionally, the conductive housing may be a metal housing, such as an aluminum housing or a stainless steel housing, but is not limited thereto. For example, the conductive housing may also be made of a non-metallic material with conductive properties, such as graphite.

[0011] Optionally, the insulating structural member may be made of ceramic, glass, diamond, sapphire or ruby, etc. For example, the insulating structural member may be made of boron nitride, quartz, beryllium oxide or aluminum oxide, etc., but is not limited thereto.

[0012] In a possible design, the slow-wave structure includes a plurality of the planar zigzag slow-wave lines, and the plurality of the planar zigzag slow-wave lines are stacked in sequence and spaced apart in a thickness direction perpendicular to a transmission direction of the electron beam.

[0013] By setting up multiple planar zigzag slow-wave lines, the electromagnetic properties of the slow-wave structure are made more advantageous, which helps to enhance the interaction impedance, is beneficial to improving the gain per unit length, and makes the dispersion of the slow-wave structure weaker, the operating voltage lower, and has a higher operating bandwidth.

[0014] In a possible design, the insulating structure includes a plurality of insulating dielectric rods, which are distributed on both sides of the planar meandering slow-wave line and are used to suspend the planar meandering slow-wave line in the vacuum shielding cavity by clamping.

[0015] The embodiment of the present application adopts the method of clamping the planar zigzag slow-wave line with an insulating dielectric rod to suspend the planar zigzag slow-wave line in the vacuum shielding cavity. Compared with the traditional method of supporting the top surface of the dielectric rod, in the present application, only the side edges of the planar zigzag slow-wave line are in contact with the inner surface of the insulating dielectric rod. The contact area between the planar zigzag slow-wave line and the insulating dielectric rod is smaller, which greatly reduces the volume of the dielectric exposed in the vacuum area and weakens the tendency of the electric field energy to concentrate in the dielectric. It can effectively solve the problem of charge accumulation, greatly alleviate the problem of electron bombardment of the dielectric, avoid problems such as short circuit and dielectric breakdown caused by electron bombardment of the dielectric, and thereby increase the working stability of the slow-wave structure.

[0016] In a possible design, the metal ridges are provided on the two inner surfaces of the conductive shell opposite to the planar zigzag slow-wave line, and the inner edges of the insulating dielectric rods on both sides of the planar zigzag slow-wave line extend between the two metal ridges.

[0017] In other words, the width (i.e., height) of the metal ridges is larger than the gap between the two insulating rods, and the metal ridges cover the inner edges of the insulating rods. This arrangement provides the metal ridges with a larger coverage area, effectively compressing the electric field and maximizing the axial electric field strength. This significantly reduces the dispersion intensity of the slow-wave structure, increases the operating bandwidth of the traveling wave tube, and reduces the operating voltage.

[0018] In a possible design, the planar meandering slow-wave line has a folding vertex, and the insulating dielectric rod abuts against the folding vertex.

[0019] By setting the folding vertex and the insulating dielectric rod to abut against each other, the contact area between the plane meandering slow-wave line and the insulating dielectric rod can be further reduced, thereby further alleviating the problem of electron bombardment of the dielectric, making the slow-wave structure have higher working stability.

[0020] In one possible design, the planar zigzag slow-wave line is divided into multiple segments along the transmission direction of the electron beam, each of the segments includes multiple folding periods, the period lengths of all folding periods in each segment are the same, and the period lengths of adjacent segments are different, wherein the period length is the length of the folding period in the transmission direction of the electron beam.

[0021] According to the slow-wave structure provided in the embodiment of the present application, the planar zigzag slow-wave line is divided into multiple segments along the transmission direction of the electron beam, each segment includes several periods, and adjacent segments use different period lengths to perform phase velocity jumps, thereby making the normalized phase velocities of adjacent segments different, which can suppress the backward wave oscillation and thus ensure stable signal output, and can improve the output power of the slow-wave structure.

[0022] Optionally, along the transmission direction of the electron beam, the period lengths of the various segments of the planar meandering slow wave line may increase, decrease, or vary randomly, for example, they may increase linearly or decrease linearly.

[0023] In a possible design, the gap between two adjacent planar meandering slow-wave lines constitutes a transmission channel for the electron beam, and / or the gap between the metal ridge and the planar meandering slow-wave line constitutes a transmission channel for the electron beam.

[0024] In a possible design, the vacuum shielding chamber is a rectangular parallelepiped structure, and the transmission direction of the electron beam is parallel to the long side of the rectangular parallelepiped structure.

[0025] In a possible design, the slow-wave structure includes two planar meandering slow-wave lines, the planes where the two planar meandering slow-wave lines are located are parallel to each other, and are arranged in mirror symmetry with each other, thereby helping to enhance the interaction impedance.

[0026] In a possible design, the planar meandering slow-wave line is in a V-shaped, U-shaped or N-shaped periodic folding shape.

[0027] In a possible design, the metal ridge is a long strip-shaped sheet structure extending along the transmission direction of the electron beam.

[0028] In one possible design, the material of the metal ridge plate includes at least one of copper, aluminum, silver and stainless steel.

[0029] In a possible design, the insulating dielectric rod is a long straight column extending along the transmission direction of the electron beam.

[0030] Optionally, the cross-sectional shape of the insulating dielectric rod may be any regular or irregular shape such as a triangle, a rectangle, a circle, a fan or a T.

[0031] In a second aspect, a traveling wave tube is provided, comprising: a signal input device; a signal output device; and a slow-wave structure provided by any possible design in the first aspect, wherein the slow-wave structure connects the signal input device and the signal output device.

[0032] Since the traveling wave tube adopts the slow-wave structure provided by the above embodiment, the traveling wave tube also has the technical effects corresponding to the slow-wave structure, which will not be described in detail here.

[0033] Optionally, the traveling wave tube provided in the embodiment of the present application can be used to amplify signals in any band, such as microwave signals, millimeter wave signals, and terahertz bands, but is not limited thereto.

[0034] Optionally, the signal input device may be a waveguide structure or a coaxial structure. Optionally, the signal output device may be a waveguide structure or a coaxial structure.

[0035] Optionally, the traveling wave tube further includes an electron gun, which is connected to the electron input port of the slow-wave structure and is used to inject an electron beam that meets design requirements into the slow-wave structure.

[0036] For example, the electron gun may be a Pierce parallel flow gun, a Pierce convergent gun, a high permeability electron gun, a positive-current controlled electron gun, a grid-controlled electron gun, a non-intercepted grid-controlled electron gun, or a low-noise electron gun.

[0037] Optionally, the traveling wave tube further comprises a magnetic focusing system provided on the periphery of the slow-wave structure, the magnetic focusing system being used to keep the electron beam in a desired shape, ensuring that the electron beam passes smoothly through the slow-wave structure and effectively interacts with the magnetic field.

[0038] For example, the magnetic focusing system can be a uniform permanent magnet focusing, a guide field focusing, a periodic permanent magnet focusing, a uniform electromagnetic focusing system, etc.

[0039] Optionally, the traveling wave tube further includes a concentrated attenuator disposed inside the slow wave structure, the concentrated attenuator including microwave absorbing materials such as carburized beryllium oxide ceramics, and is used to absorb reflected waves to eliminate feedback and suppress oscillation.

[0040] For example, the lumped attenuator may be a ramped attenuator.

[0041] Optionally, the traveling wave tube further includes a collector connected to the electron output port of the slow-wave structure, and configured to collect electrons in the slow-wave structure that have completed energy exchange with the electromagnetic field.

[0042] For example, the collector may be a buck collector having a relatively high operating efficiency.

[0043] In one possible design, the signal input device includes: a rectangular waveguide; a plurality of waveguide ridges arranged on the inner surface of the rectangular waveguide, the plurality of waveguide ridges being connected in sequence and gradually increasing in height to form a stepped structure, the highest waveguide ridge among the plurality of waveguide ridges being connected to the slow-wave structure.

[0044] For a slow-wave structure having multiple planar zigzag slow-wave lines, its signal input and output device has an important influence on the stability of its operation and overall performance. In an embodiment of the present application, the signal input device adopts a rectangular waveguide with multiple built-in waveguide ridges, and the multiple waveguide ridges form a stepped structure. The waveguide ridge has good transmission characteristics and is easier to match the impedance with the slow-wave structure, which greatly reduces the discontinuity of the connection between the slow-wave structure and the signal input device, effectively reduces the reflection of the electromagnetic wave when it is transmitted from the signal input device to the slow-wave structure, improves the transmission characteristics of the traveling wave tube, and effectively suppresses the back-wave oscillation, making the transmission of the electromagnetic signal in the traveling wave tube more efficient.

[0045] Computer simulation was performed on the transmission characteristics of the slow-wave structure and the signal input device. The simulated transmission and reflection coefficients showed that the traveling wave tube provided in the present application has good transmission characteristics in the frequency range of 36 GHz to 44 GHz.

[0046] In one possible design, the signal input device further includes a metal block connecting the waveguide ridge and the slow-wave structure.

[0047] The signal input device provided in the embodiment of the present application uses a waveguide ridge to feed signals (such as microwave signals, millimeter wave signals or signals in the terahertz frequency band). The waveguide ridge is connected to the planar zigzag slow-wave line of the slow-wave structure through a metal block, which can effectively complete the conversion of the electric field mode from the TE10 mode to the quasi-TE10 mode, that is, complete the mode conversion from the standard waveguide to the slow-wave structure.

[0048] Optionally, the material of the waveguide ridge and the metal block may be the same or different, for example, they may be copper, stainless steel, aluminum, silver or other metal materials.

[0049] In a possible design, the metal block is a metal quadrangular prism with a trapezoidal cross-section, and the bottom surface of the metal quadrangular prism is attached to the top surface of the highest waveguide ridge.

[0050] In a possible design, the signal output device has the same structure as the signal input device.

[0051] Through the above arrangement, while achieving better impedance matching with the slow-wave structure, the versatility of the signal output device and the signal input device can also be improved. There is no need to distinguish between the signal output device and the signal input device during installation, which can improve assembly efficiency.

[0052] In a third aspect, a communication device is provided, the communication device including a traveling wave tube provided by any possible design of the second aspect.

[0053] Since the communication device adopts the traveling wave tube provided by the above embodiment, the communication device also has the technical effects corresponding to the traveling wave tube, which will not be described in detail here.

[0054] In one possible design, the communication device further includes an antenna connected to a signal output end of the traveling wave tube.

[0055] For example, the antenna may be a horizontal half-wave dipole antenna, a vertical monopole antenna, a Winton antenna, a Yagi antenna, or a dish antenna, but is not limited thereto.

[0056] In one possible design, the communication device further includes: a processor connected to a signal input end of the traveling wave tube.

[0057] Optionally, the communication device provided in the embodiment of the present application can be any wired or wireless communication device such as a base station (such as a 5G base station), a radar (such as a millimeter wave radar or a microwave radar), a vehicle-mounted device or a satellite-mounted device.

[0058] In a fourth aspect, a communication device is provided, comprising a housing, and a slow-wave structure provided by any possible design of the first aspect, wherein the slow-wave structure is located within the housing.

[0059] Since the communication device adopts the slow-wave structure provided by the above embodiment, the communication device also has the technical effects corresponding to the slow-wave structure, which will not be described in detail here.

[0060] Optionally, the communication device provided in the embodiment of the present application can be any wired or wireless communication device such as a base station (such as a 5G base station), a radar (such as a millimeter wave radar or a microwave radar), a vehicle-mounted device or a satellite-mounted device. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] FIG1 is a schematic structural diagram showing an example of a slow-wave structure in the related art.

[0062] FIG2 is a schematic structural diagram showing another example of a slow-wave structure in the related art.

[0063] FIG3 is an overall structural diagram of the slow-wave structure provided in an embodiment of the present application.

[0064] FIG4 is a cross-sectional view taken along the AA angle of view in FIG3 .

[0065] FIG5 is a diagram showing the internal structure of the slow-wave structure provided in an embodiment of the present application.

[0066] FIG6 is a perspective view of a slow-wave structure provided in an embodiment of the present application.

[0067] FIG7 is a schematic diagram of the connection between the planar zigzag slow-wave line and the insulating dielectric rod.

[0068] FIG8 is a diagram showing the overall structure of a planar zigzag slow-wave line.

[0069] FIG9 is a schematic diagram of the modular structure of a traveling wave tube provided in an embodiment of the present application.

[0070] FIG10 is a schematic diagram showing the connection between the slow-wave structure, the signal input device, and the signal output device.

[0071] FIG. 11 is a perspective view of the structure shown in FIG. 10 .

[0072] FIG12 is a perspective view showing the connection between the slow-wave structure and the signal input device.

[0073] Figure 13 is a schematic diagram of the modular structure of an example of a communication device provided in an embodiment of the present application.

[0074] FIG14 is a schematic diagram of the modular structure of another example of a communication device provided in an embodiment of the present application.

[0075] Reference numerals:

[0076] 1. Dielectric substrate; 2. Metal slow-wave line; 3. Signal input port; 4. Signal output port; 5. Dielectric rod;

[0077] 10. Slow-wave structure; 11. Conductive housing; 11a. Vacuum shielding chamber; 12. Planar zigzag slow-wave line; 12a, 12b, 12c, 12d. Segments; 12e. Input path; 12f. Output path; 13. Insulating dielectric rod; 14. Metal ridge; 16. Signal input port; 17. Signal output port; 18. Electronic input port.

[0078] 20. Signal input device; 21. Rectangular waveguide; 22. Waveguide ridge; 23. Metal block;

[0079] 30. Signal output device;

[0080] 40. Electron gun;

[0081] 50. Magnetic focusing system;

[0082] 60. Centralized attenuator;

[0083] 70. Collector;

[0084] 100. Traveling wave tube;

[0085] 200, antenna;

[0086] 300, processor;

[0087] 400, housing;

[0088] x, height direction; y, thickness direction; z, electron beam transmission direction; S, transmission channel. DETAILED DESCRIPTION

[0089] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be understood as limiting the present application.

[0090] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0091] In the description of this application, it should be understood that the terms "upper", "lower", "side", "front", "rear", "inside", "outside", etc. indicate orientations or positional relationships based on the installation, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0092] It should also be noted that, in the embodiments of the present application, the same figure mark represents the same component or the same part. For the same parts in the embodiments of the present application, the figure may only mark one of the parts or components as an example. It should be understood that the figure mark also applies to other identical parts or components.

[0093] With the continuous advancement of communication technology, fifth-generation (5G) communication networks have significantly increased carrier frequencies by utilizing millimeter and even submillimeter waves. This allows for access to a wider frequency band, tens of times greater than that of fourth-generation (4G) communication networks. This is the fundamental reason for 5G's gains. However, as the wavelength decreases, millimeter waves experience greater path loss in free space, and their characteristics, such as air attenuation and rain attenuation, are inferior to those of lower-frequency bands, severely impacting millimeter-wave coverage. Traveling-wave tubes (TWTs), due to their superior properties such as high power, wide bandwidth, low noise, and high gain, are widely used in various fields, including radar, satellite communications, medical imaging, and electronic countermeasures. In the communications field, using TWTs as final amplifiers can significantly increase transmit power, thereby significantly extending communication range. They hold significant research and commercial value in the millimeter-wave and terahertz (THz) frequency bands.

[0094] A traveling wave tube (TWT) is a microwave electron tube that achieves amplification by continuously modulating the speed of an electron beam. In a TWT, the electron beam interacts with the microwave field traveling within a slow-wave structure (slow-wave circuit). Within the slow-wave structure, which can be as long as 6 to 40 wavelengths, the electron beam continuously transfers kinetic energy to the microwave signal field, thereby amplifying the signal. The TWT allows electrons to travel through a long slow-wave structure. Due to the long interaction time, the gain is very high. Furthermore, the lack of a resonant cavity significantly increases the operating bandwidth. A TWT primarily consists of an electron gun, a magnetic focusing system, a slow-wave structure, input and output devices, a centralized attenuator, and a collector.

[0095] The electron gun's function is to form an electron beam that meets design requirements. It generates an electron beam (electron beam) of the desired size and current and accelerates it to a speed slightly faster than the phase velocity of the electromagnetic wave traveling on the slow-wave structure, thereby exchanging energy with the electromagnetic field and achieving amplification. Commonly used electron guns for traveling wave tubes include Pierce parallel-flow guns, Pierce convergent guns, high-conductivity electron guns, anode-controlled electron guns, grid-controlled electron guns, non-intercepted grid-controlled electron guns, and low-noise electron guns.

[0096] The magnetic focusing system is used to maintain the desired shape of the electron beam, ensuring smooth passage through the slow-wave structure and effective interaction with the magnetic field. The electrons in the electron beam are negatively charged, and the mutual repulsion between them causes the electron beam to quickly disperse and strike the slow-wave structure, losing the opportunity to transfer energy to the electromagnetic field. Therefore, a magnetic focusing system is required to constrain the electron beam, allowing it to smoothly pass through the slow-wave structure and fully exchange energy with the electromagnetic field to achieve signal amplification. Commonly used focusing systems in traveling wave tubes include uniform permanent magnet focusing, guide field focusing, periodic permanent magnet focusing, and uniform electromagnetic focusing systems.

[0097] A slow-wave structure (SWS) is a device designed to enhance the interaction between moving electrons and electromagnetic fields, enabling the energy of the electron flow to be more efficiently converted into high-frequency electromagnetic wave energy. The slow-wave structure can reduce the phase velocity of the electromagnetic wave to approximately the same speed as the electron's motion, allowing the electrons and electromagnetic waves to fully exchange energy and achieve signal amplification. As a core component of a traveling wave tube (TWT), the performance of the slow-wave structure directly affects the efficiency of the beam-wave interaction and the technical level of the entire TWT. There are many types of slow-wave structures, such as helices, coupled cavities, folded waveguides, interleaved double gates, and microstrip striplines and their variants. Among them, the stripline structure has attracted much attention due to its simple structure, ease of integration, ease of processing, and ability to accommodate sheet-shaped electron beams.

[0098] The input / output device, also known as an input / output energy coupler, consists of a signal input device and a signal output device, connected to the two ends of the slow-wave structure, serving as the inlet and outlet for the amplified signal. Common structures include waveguide and coaxial. Coaxial structures are generally used when low frequencies or low powers require a wide operating bandwidth; waveguide structures are used when these are not. There are also cases where coaxial input is used and waveguide output is used.

[0099] A concentrated attenuator is a microwave absorber made by processing a microwave-absorbing material into a specific shape. Known microwave-absorbing materials include attenuating ceramics, such as carburized beryllium oxide ceramics. At the concentrated attenuator, reflected waves are absorbed, eliminating feedback and suppressing oscillations. The concentrated attenuator can be placed between the input / output device and the slow-wave structure, or within the slow-wave structure. For example, the concentrated attenuator can be a wedge-shaped tapered attenuator.

[0100] The collector collects electrons that have exchanged energy with the electromagnetic field. Since these electrons still have high velocities, they are converted into heat when they strike the collector. Therefore, heat dissipation is a key consideration in collector design. To improve efficiency, traveling wave tubes often use a step-down collector.

[0101] The present application mainly relates to technical improvements to the slow-wave structure, and the slow-wave structure will be further introduced below in conjunction with the accompanying drawings. FIG1 shows a schematic structural diagram of an example of a slow-wave structure in the related art. Among the schemes for realizing a planar traveling wave tube, a slow-wave structure (i.e., a microstrip line slow-wave structure) composed of a dielectric substrate supporting a metal slow-wave line is a typical technical scheme, as shown in FIG1 . The slow-wave structure is composed of a dielectric substrate 1 loaded in a waveguide, and a metal slow-wave line 2 is etched on the dielectric substrate 1, and the two ends of the metal slow-wave line 2 are respectively connected to a signal input port 3 and a signal output port 4. An electron gun (not shown in the figure) emits electrons, which enter the slow-wave structure from near the signal input port 3. The electron beam passes through the slow-wave structure under the bunching action of the focusing magnetic field, wherein the electron beam interacts with the high-frequency field of the input signal along the metal slow-wave line 2, converting the kinetic energy of the electron beam into electromagnetic wave energy and coupling it into the metal slow-wave line 2. Finally, the input signal is amplified and coupled to the external circuit from the signal output port 4.

[0102] In this process, in order for the electron beam to better convert kinetic energy into electromagnetic wave energy, the electron beam needs to be as close to the metal slow-wave line 2 as possible and fully interact with the surface of the metal slow-wave line 2. However, when the electron beam is close to the metal slow-wave line 2, it will also cause electrons to bombard the metal slow-wave line 2 and / or the dielectric substrate 1, causing the traveling wave tube to operate unstable or even inoperable. Therefore, it is necessary to comprehensively consider the efficiency and stability of the device and keep the electron beam at a certain distance from the metal slow-wave line 2. Even so, the design of using this dielectric substrate to support the slow-wave line still cannot avoid electron beam bombardment, especially when the traveling wave tube is under conditions of continuous long-term operation.

[0103] In the above scheme, in the slow-wave structure formed by using a dielectric substrate 1 to support a metal slow-wave line 2, on the one hand, the electric field is mainly concentrated in the dielectric substrate 1, and the electric field decays exponentially along the direction perpendicular to the metal slow-wave line 2. Therefore, the field interacting with the electron beam is weak, which is not conducive to achieving high efficiency and miniaturization of the traveling wave tube. On the other hand, in order to prevent the electron beam from directly bombarding the metal slow-wave line 2 and the dielectric substrate 1, there is a certain distance between the electron beam and the metal slow-wave line 2. As the traveling wave tube continues to work, it is impossible to completely avoid electron bombardment of the slow-wave structure. Therefore, under long-term operation, this method of using a dielectric substrate to support the slow-wave line will have a significant charge accumulation effect, which will eventually lead to device breakdown. Therefore, for this technical solution of supporting the metal slow-wave line with a dielectric substrate, its main technical defects are low conversion efficiency, and as the operating time of the traveling wave tube increases, the charge concentration effect caused by the electron bombardment of the dielectric substrate causes the traveling wave tube to break down, resulting in unstable operation.

[0104] To address the charge concentration issue in the slow-wave structure shown in Figure 1, the related art also proposes a solution using dielectric rods on both sides to support a metal slow-wave line. Figure 2 shows a schematic structural diagram of another example of a slow-wave structure in the related art. As shown in Figure 2, the planar slow-wave structure with dielectric rods supporting a metal slow-wave line is an improvement on the metal microstrip line. The biggest difference between it and the metal microstrip line lies in the dielectric support method. That is, this solution uses two dielectric rods 5 spaced apart to replace the dielectric substrate 1 to support the metal slow-wave line 2.

[0105] The electron beam is located at a certain distance from the metal slow-wave line 2 and interacts with the surface waves propagating along it during transmission, thereby amplifying the electromagnetic wave. In this technical solution, the use of a double-sided support structure for the metal slow-wave line significantly reduces charge accumulation in the dielectric, minimizing the risk of electron bombardment and addressing charge concentration, thereby increasing the stability of the traveling wave tube.

[0106] However, the dispersion of the slow-wave structure is highly correlated with many structural parameters. The solution shown in Figure 2, which uses dielectric rods on both sides to support the metal slow-wave line, has strong dispersion characteristics. Strong dispersion characteristics also mean that the traveling wave tube using this slow-wave structure has a higher operating voltage and a narrower operating bandwidth. This is not conducive to the current application of low-voltage traveling wave tubes and cannot meet the needs of amplifying broadband millimeter-wave signals in 5G communication networks.

[0107] In view of this, the embodiments of the present application provide a slow-wave structure, a traveling wave tube and a communication device. By arranging metal ridges in the slow-wave structure, the dispersion intensity of the slow-wave structure can be weakened, the operating bandwidth of the traveling wave tube can be significantly improved, and the operating voltage of the traveling wave tube can be effectively reduced.

[0108] In the first aspect, the embodiment of the present application first provides a slow-wave structure 10. FIG3 is a diagram of the overall structure of the slow-wave structure 10 provided in the embodiment of the present application. FIG4 is a cross-sectional view taken from the AA perspective in FIG3. FIG5 is a diagram of the internal structure of the slow-wave structure 10 provided in the embodiment of the present application. FIG6 is a perspective view of the slow-wave structure 10 provided in the embodiment of the present application. As shown in FIG3-6, the slow-wave structure 10 provided in the embodiment of the present application includes a conductive shell 11, a planar zigzag slow-wave line 12, an insulating structural member, and a metal ridge sheet 14.

[0109] The conductive housing 11 has a vacuum shielding chamber 11a within it, which is used to accommodate related components such as the planar zigzag slow-wave line 12, insulating structural members, and metal ridges 14. Four through-holes can be provided in the conductive housing 11, communicating with the vacuum shielding chamber 11a, to facilitate signal input and output, as well as the input and output of electron beams.

[0110] For example, one end of the conductive shell 11 is provided with a signal input port 16 and an electronic input port 18, and the other end is provided with a signal output port 17 and an electronic output port (not shown in the figure). The size and shape of each port can be reasonably designed according to actual needs.

[0111] Optionally, the conductive shell 11 may be a metal shell, such as an aluminum shell or a stainless steel shell, but is not limited thereto. For example, the conductive shell 11 may also be made of a non-metallic material with conductive properties such as graphite.

[0112] As shown in Figures 3 and 6, the conductive shell 11 has a rectangular structure as a whole. At this time, the conductive shell 11 constitutes a standard rectangular waveguide structure. Correspondingly, the vacuum shielding cavity 11a also has a rectangular structure. The electron input port 18 and the electron output port are respectively arranged at the two opposite ends of the rectangular structure, so that the transmission direction z of the electron beam (that is, the movement direction of the electron, that is, the beam-wave interaction direction) is parallel to the long side of the rectangular structure.

[0113] As shown in Figures 4-7 , a planar zigzag slow-wave line 12 is fixedly disposed within the vacuum shielding chamber 11a. This line is a periodically folded metal stripline located in a single plane and extending along the electron beam propagation direction z. This metal stripline has a specific thickness and width, and the thickness and width can be uniform across the line's extension direction.

[0114] For example, the planar zigzag slow-wave line 12 can be a V-shaped, U-shaped (including a top-angle U-shaped with an arc-shaped front end and a flat-angle U-shaped with a straight front end) or N-shaped periodically folded planar curve, and its material can be at least one of tungsten, rhenium, copper, gold, titanium, nickel, silver and their alloys.

[0115] Optionally, one or more planar zigzag slow-wave lines 12 can be set in the vacuum shielding cavity 11a. The present application does not limit the number of planar zigzag slow-wave lines 12 possessed by the slow-wave structure 10. For example, it can be two as shown in the figure, or it can be one or more, such as three or four.

[0116] As shown in Figures 4 to 7, the insulating structural member is made of an insulating material and is used to install the planar zigzag slow-wave line 12 inside the conductive shell 11 and electrically isolate it from the conductive shell 11. In other words, the planar zigzag slow-wave line 12 can be fixedly suspended in the vacuum shielding cavity 11a by the insulating structural member. The present application does not specifically limit the specific structural form of the insulating structural member. For example, it can be the insulating dielectric rod 13 shown in the figure (that is, the insulating structural member can be a rod-shaped structure), or it can be any other regular or irregular structure such as the dielectric substrate shown in Figure 1.

[0117] Optionally, the insulating structural member may be made of ceramic, glass, diamond, sapphire or ruby, etc. For example, the insulating structural member may be made of boron nitride, quartz, beryllium oxide or aluminum oxide, etc., but is not limited thereto.

[0118] As shown in Figures 4 and 5 , the metal ridge 14 is a sheet-like structure made of a metal material. For example, the metal ridge 14 may be made of at least one of copper, aluminum, silver, and stainless steel. The metal ridge 14 protrudes from at least one inner surface of the conductive housing 11 that faces the plane of the planar zigzag slow-wave line 12. That is, the metal ridge 14 and the plane of the planar zigzag slow-wave line 12 are aligned with each other, thereby reducing the dimension of the vacuum shielding chamber 11a in the thickness direction y. A gap exists between the metal ridge 14 and the planar zigzag slow-wave line 12, preventing them from contacting each other.

[0119] In the embodiment of the present application, metal ridges 14 are provided on both inner surfaces of the conductive housing 11 opposite to the planar zigzag slow-wave line 12, that is, metal ridges 14 are provided on both inner surfaces on both sides of the planar zigzag slow-wave line 12, and the planar zigzag slow-wave line 12 is disposed between the two metal ridges 14. The two metal ridges 14 can be exactly the same size and are symmetrically disposed vertically.

[0120] In other implementations, the metal ridge 14 may be provided on only one of the inner surfaces, which is not limited in this application.

[0121] According to the slow-wave structure 10 provided in the embodiment of the present application, a metal ridge 14 is protruded on the inner surface of the conductive shell 11, so that the size of the vacuum shielding cavity 11a in the thickness direction y is reduced. At this time, the electric field in the thickness direction y (i.e., the axial direction) is compressed, and the axial electric field strength is enhanced. In addition, since the plane meandering slow-wave line 12 is closer to the waveguide wall, the coupling capacitance is increased, thereby effectively reducing the dispersion intensity of the slow-wave structure 10 and significantly improving the working bandwidth of the traveling wave tube. At the same time, it can effectively reduce the working voltage and improve the efficiency of the traveling wave tube.

[0122] Simulation results also show that, compared to traditional slow-wave structures, the slow-wave structure 10 provided in the embodiment of the present application has a flatter dispersion curve, enabling the electron beam to synchronize with electromagnetic waves over a wider frequency band. Furthermore, the interaction strength between the electromagnetic waves and the electron beam at each frequency point is essentially the same, thereby enabling a traveling wave tube employing this structure to have a wider operating bandwidth, thereby enabling broadband design of the traveling wave tube. Furthermore, simulation results also show that the slow-wave structure 10 provided in the embodiment of the present application has a lower normalized phase velocity than traditional slow-wave structures, thereby enabling a traveling wave tube employing this structure to have a lower operating voltage.

[0123] Furthermore, the metal ridges 14 are long, strip-shaped structures extending along the electron beam propagation direction z. That is, the metal ridges 14 are provided along the entire electron beam propagation direction, compressing the electric field at different locations along that direction, thereby enhancing the electric field strength at different locations. This can further reduce the dispersion intensity of the slow-wave structure 10, increase the operating bandwidth of the traveling wave tube, and reduce the operating voltage.

[0124] In one possible implementation, the conductive housing 11 can be formed by assembling an upper and lower half shell, and the metal ridges 14 can be formed into an integral structure with the corresponding half shell through a molding process such as casting or powder metallurgy. In this case, the metal ridges 14 are provided on the inner surface of the corresponding half shell, thereby achieving a higher connection strength between the two.

[0125] For example, the conductive shell 11 is formed by assembling an upper half shell and a lower half shell, and two metal ridges 14 are respectively provided on the inner surface of one of the half shells. The metal ridges 14 and the corresponding half shells are made into an integral structure by a casting process.

[0126] The following further describes the specific structural details of the slow-wave structure 10 provided in the embodiment of the present application in conjunction with the accompanying drawings. As shown in Figures 4 and 5, in the embodiment of the present application, the slow-wave structure 10 includes multiple planar zigzag slow-wave lines 12, which are stacked and spaced apart in a thickness direction y perpendicular to the propagation direction z of the electron beam.

[0127] By setting up multiple planar zigzag slow-wave lines 12, the electromagnetic properties of the slow-wave structure 10 are more advantageous, which helps to enhance the interaction impedance and improve the gain per unit length, making the dispersion of the slow-wave structure 10 weaker, the operating voltage lower, and the operating bandwidth higher.

[0128] Furthermore, at this time, the gap between two adjacent planar zigzag slow-wave lines 12 constitutes a transmission channel S for the electron beam, and / or the gap between the metal ridge 14 and the planar zigzag slow-wave line 12 constitutes a transmission channel S for the electron beam.

[0129] Optionally, the gaps between any two adjacent planar zigzag slow-wave lines 12 may constitute the electron beam transmission channel S. For example, there are three planar zigzag slow-wave lines 12, in which case the gaps between the first and second lines and the gaps between the second and third lines may constitute the electron beam transmission channel S.

[0130] Alternatively, the gaps between some adjacent plane zigzag slow-wave lines 12 may constitute the electron beam transmission channel S. For example, there are three plane zigzag slow-wave lines 12. In this case, the gap between the first and second plane zigzag slow-wave lines 12 constitutes the electron beam transmission channel S, while the gap between the second and third plane zigzag slow-wave lines does not constitute the electron beam transmission channel S.

[0131] Optionally, the transmission channel S for the electron beam may be formed by the gap between the outermost (eg, uppermost and / or lowermost) plane zigzag slow-wave line 12 of the plurality of stacked plane zigzag slow-wave lines 12 and the metal ridge piece 14 on the corresponding side.

[0132] Furthermore, as shown in Figures 4 and 5 , the slow-wave structure 10 in the embodiment of the present application has two planar zigzag slow-wave lines 12. The planes on which the two planar zigzag slow-wave lines 12 lie are parallel to each other and are arranged in mirror-symmetric fashion, thereby enhancing the interaction impedance. The gap between the two planar zigzag slow-wave lines 12 forms a transmission channel S for the electron beam.

[0133] In other implementations, the gap between the upper planar zigzag slow-wave line 12 and the metal ridge 14 on the upper surface, and the gap between the lower planar zigzag slow-wave line 12 and the metal ridge 14 on the lower surface can also constitute a transmission channel for the electron beam, thereby enabling the slow-wave structure 10 to have a multi-channel electron beam, such as a double electron beam or a triple electron beam, so that the slow-wave structure 10 has higher working efficiency and can obtain a lower current density, which is beneficial to reducing the load on the cathode (electron gun).

[0134] As shown in Figures 4 and 5, in an embodiment of the present application, the insulating structural member is used to fix and suspend the plane zigzag slow-wave line 12 in the vacuum shielding cavity 11a. The insulating structural member includes a plurality of insulating dielectric rods 13. The plurality of insulating dielectric rods 13 are distributed on both sides of the plane zigzag slow-wave line 12 and are used to suspend the plane zigzag slow-wave line 12 in the vacuum shielding cavity 11a by clamping.

[0135] The embodiment of the present application adopts the method of clamping the insulating dielectric rod 13 to suspend the plane zigzag slow-wave line 12 in the vacuum shielding cavity 11a. Compared with the method of supporting the top surface of the dielectric rod shown in Figure 2 above, in the present application, only the side edges of the plane zigzag slow-wave line 12 are in contact with the inner surface of the insulating dielectric rod 13. The contact area between the plane zigzag slow-wave line 12 and the insulating dielectric rod 13 is smaller, which greatly reduces the volume of the dielectric exposed in the vacuum area and weakens the tendency of the electric field energy to concentrate in the dielectric. It can effectively solve the problem of charge accumulation, greatly alleviate the problem of electron bombardment of the dielectric, avoid problems such as short circuit and dielectric breakdown caused by electron bombardment of the dielectric, and thereby increase the working stability of the slow-wave structure 10.

[0136] FIG7 is a schematic diagram of the connection between the planar zigzag slow-wave line 12 and the insulating dielectric rod 13. As shown in FIG5-FIG7, in the embodiment of the present application, the planar zigzag slow-wave line 12 is a periodic folded curve with each period being U-shaped (more specifically, a U-shaped curve with an arc-shaped front end). The planar zigzag slow-wave line 12 has a folding vertex (i.e., the arc-shaped front end vertex of the U), and the insulating dielectric rod 13 abuts against the folding vertex. By setting the folding vertex and the insulating dielectric rod 13 to abut against each other, the contact area between the planar zigzag slow-wave line 12 and the insulating dielectric rod 13 can be further reduced, thereby further alleviating the problem of electron bombardment of the dielectric, and making the slow-wave structure 10 have higher operating stability.

[0137] Optionally, each side of the planar meandering slow-wave line 12 has multiple folding vertices, and some or all of the multiple folding vertices abut against the inner surface of the insulating dielectric rod 13 on the corresponding side. This application does not limit this.

[0138] As shown in Figures 6 and 7, in the embodiment of the present application, the width of each period of the planar zigzag slow-wave line 12 (i.e., the dimension in the height direction x) is exactly the same. At this time, the folding vertices of each period abut against the inner surface of the insulating dielectric rod 13 on the corresponding side, thereby achieving a good clamping and fixing effect on the planar zigzag slow-wave line 12.

[0139] In other implementations, the width of each folding period may not be exactly the same. In this case, the folding vertices of some periods may not be in contact with the inner surface of the insulating dielectric rod 13 (there may be a gap).

[0140] As shown in Figures 6 and 7, in the embodiment of the present application, the insulating dielectric rod 13 is a long straight column extending along the electron beam transmission direction z. The cross-sectional shape of the insulating dielectric rod 13 can be any regular or irregular shape such as a triangle, rectangle, circle, fan or T shape.

[0141] As shown in Figures 4-7 , in the embodiment of the present application, there are two insulating dielectric rods 13, one on each side of the planar zigzag slow-wave line 12. In other implementations, multiple insulating dielectric rods 13 may be provided on each side of the planar zigzag slow-wave line 12. The multiple insulating dielectric rods 13 may be connected in series along the propagation direction z of the electron beam, which is not limited in this application.

[0142] As shown in Figures 4 and 5, in an embodiment of the present application, metal ridges 14 are provided on the two inner surfaces of the conductive shell 11 opposite to the planar zigzag slow-wave line 12, and the inner edges of the insulating dielectric rods 13 located on both sides of the planar zigzag slow-wave line 12 extend between the two metal ridges 14.

[0143] In other words, the width of the metal ridge 14 (i.e., the dimension in the height direction x) is greater than the gap between the two insulating dielectric rods 13, and the metal ridge 14 covers the inner edge of the insulating dielectric rod 13. This configuration provides the metal ridge 14 with a larger coverage area, enabling it to fully compress the electric field and maximize the axial electric field strength, thereby significantly reducing the dispersion intensity of the slow-wave structure 10, increasing the operating bandwidth of the traveling wave tube, and reducing the operating voltage.

[0144] The following further describes the specific structural details of the planar zigzag slow-wave line 12 in the embodiment of the present application. Figure 8 is an overall structural diagram of the planar zigzag slow-wave line 12. In order to more clearly show the shape and segmentation of the zigzag line, some periods are hidden in Figure 8.

[0145] As shown in Figures 6, 8, 11 and 12, in the embodiment of the present application, the plane zigzag slow-wave line 12 is the most important part of the entire slow-wave structure 10. It is a metal strip with a certain width and thickness that is folded and periodically zigzag. The zigzag path of the plane zigzag slow-wave line 12 can be divided into three parts, namely: an input path 12e, an intermediate path and an output path 12f. The intermediate path is the main part of the plane zigzag slow-wave line 12. The specific shape characteristics of the intermediate path are: it contains two quarter arcs and a straight line segment connecting the two arcs, and the two end points of the straight line segment are respectively connected to one of the end points of the two arcs. The two arcs are on the same side of the straight line segment and are tangent to the straight line. The input path 12e and the output path 12f are both curves or broken lines, one end of which is connected to the first or last straight line segment in the intermediate path, and the other end extends to the outer surface of the metal shell. Finally, these three segments are combined into a complete zigzag path of the slow-wave structure.

[0146] As shown in Figure 8, in an embodiment of the present application, the plane zigzag slow wave line 12 is divided into multiple segments along the transmission direction z of the electron beam, each segment includes multiple folding periods, the period length of all folding periods in each segment is the same, and the period lengths of adjacent segments are different, wherein the period length is the length of the folding period in the transmission direction z of the electron beam.

[0147] According to the slow-wave structure 10 provided in the embodiment of the present application, the planar zigzag slow-wave line 12 therein is divided into multiple segments along the transmission direction z of the electron beam, each segment includes several periods, and adjacent segments use different period lengths to perform phase velocity jumps, thereby making the normalized phase velocities of adjacent segments different, which can suppress the backward wave oscillation and thus stabilize the signal output, and can improve the output power of the slow-wave structure 10. As for the specific number of segments and the number of periods P contained in each segment, they can be adjusted according to the intensity of the oscillation.

[0148] Optionally, along the transmission direction z of the electron beam, the period lengths of the segments of the planar meandering slow-wave line 12 may increase, decrease, or vary randomly, for example, they may increase linearly or decrease linearly.

[0149] As a specific example, as shown in FIG8 , the middle path of the planar zigzag slow-wave line 12 is divided into four segments, namely, segment 12a, segment 12b, segment 12c, and segment 12d, which are sequentially connected. The four segments use different period lengths. Specifically, the period length of segment 12a is 320 microns (um), the period length of segment 12b is 310um, the period length of segment 12c is 300um, and the period length of segment 12d is 290um. The lengths of segments 12a, 12b, and 12c are 30P (i.e., 30 folding periods), and the length of segment 12d is 16P (i.e., 16 folding periods). Segments 12a and 12d extend to the outside of the conductive housing 11 through an input path 12e and an output path 12f (both broken lines), respectively connected to a signal input device and a signal output device. On the other hand, the present invention also provides a traveling wave tube 100. Figure 9 is a schematic diagram of the modular structure of the traveling wave tube 100 provided in the present invention. Figure 10 is a schematic diagram of the connection between the slow wave structure 10, the signal input device 20, and the signal output device 30.

[0150] As shown in Figures 9 and 10, the traveling wave tube 100 provided in the embodiment of the present application includes a signal input device 20, a signal output device 30, and the slow-wave structure 10 provided in the aforementioned embodiment. The signal input device 20 is connected to the signal input end of the slow-wave structure 10, and the signal output device 30 is connected to the signal output end of the slow-wave structure 10. In other words, the slow-wave structure 10 is connected to the signal input device 20 and the signal output device 30.

[0151] Since the traveling wave tube 100 adopts the slow-wave structure 10 provided by the above embodiment, the traveling wave tube 100 also has the technical effects corresponding to the slow-wave structure 10 , which will not be described in detail here.

[0152] Optionally, the traveling wave tube 100 provided in the embodiment of the present application can be used to amplify signals in any band, such as microwave signals, millimeter wave signals, and terahertz bands, but is not limited thereto.

[0153] Optionally, the signal input device 20 may be a waveguide structure or a coaxial structure. Optionally, the signal output device 30 may be a waveguide structure or a coaxial structure.

[0154] Optionally, as shown in FIG9 , the traveling wave tube 100 further includes an electron gun 40 , which is connected to the electron input port 18 of the slow-wave structure 10 and is used to inject an electron beam meeting design requirements into the slow-wave structure 10 .

[0155] For example, the electron gun 40 may be a Pierce parallel flow gun, a Pierce convergent gun, a high permeability electron gun, a positive-current controlled electron gun, a grid-controlled electron gun, a non-intercepted grid-controlled electron gun, or a low-noise electron gun.

[0156] Optionally, as shown in FIG9 , the traveling wave tube 100 further includes a magnetic focusing system 50 disposed on the periphery of the slow-wave structure 10 . The magnetic focusing system 50 is used to keep the electron beam in a desired shape, ensuring that the electron beam passes smoothly through the slow-wave structure 10 and effectively interacts with the magnetic field.

[0157] For example, the magnetic focusing system 50 can be a uniform permanent magnet focusing system, a guide field focusing system, a periodic permanent magnet focusing system, a uniform electromagnetic focusing system, etc.

[0158] Optionally, as shown in FIG9 , the traveling wave tube 100 further includes a concentrated attenuator 60 disposed inside the slow wave structure 10. The concentrated attenuator 60 includes microwave absorbing materials such as carburized beryllium oxide ceramics. The concentrated attenuator 60 is used to absorb reflected waves to eliminate feedback and suppress oscillation.

[0159] For example, the lumped attenuator 60 may be a splined attenuator.

[0160] Optionally, as shown in FIG9 , the traveling wave tube 100 further includes a collector 70 , which is connected to the electron output port of the slow-wave structure 10 and is used to collect electrons in the slow-wave structure 10 that have exchanged energy with the electromagnetic field.

[0161] For example, the collector 70 may be a step-down collector having a relatively high operating efficiency.

[0162] Fig. 11 is a perspective view of the structure shown in Fig. 10. Fig. 12 is a perspective view of the connection between the slow-wave structure 10 and the signal input device 20.

[0163] As shown in Figures 11 and 12, in an embodiment of the present application, the signal input device 20 is a waveguide structure, including a rectangular waveguide 21, and a plurality of waveguide ridges 22 arranged on the same inner surface of the rectangular waveguide 21. The plurality of waveguide ridges 22 are connected in sequence and the height gradually increases to form a stepped structure. The highest waveguide ridge 22 among the plurality of waveguide ridges 22 is connected to the slow-wave structure 10 to achieve impedance matching between the signal input device 20 and the slow-wave structure 10.

[0164] For the slow-wave structure 10 having multiple planar zigzag slow-wave lines 12, its signal input and output device has an important influence on the stability of its operation and overall performance. In the embodiment of the present application, the signal input device 20 adopts a rectangular waveguide 21 with multiple waveguide ridges 22 built in, and the multiple waveguide ridges 22 form a stepped structure. The waveguide ridge 22 has good transmission characteristics and is easier to match the impedance with the slow-wave structure 10, which greatly reduces the discontinuity of the connection between the slow-wave structure 10 and the signal input device 20, effectively reduces the reflection of the electromagnetic wave when it is transmitted from the signal input device 20 to the slow-wave structure 10, improves the transmission characteristics of the traveling wave tube 100, and effectively suppresses the back-wave oscillation, making the transmission of the electromagnetic signal in the traveling wave tube 100 more efficient.

[0165] Computer simulation was performed on the transmission characteristics of the slow-wave structure 10 and the signal input device 20. The simulated transmission and reflection coefficients showed that the traveling wave tube 100 provided in the present application has good transmission characteristics in the frequency range of 36 GHz to 44 GHz.

[0166] As shown in Figures 11 and 12, in the embodiment of the present application, the signal input device 20 further includes a metal block 23 connecting the waveguide ridge 22 and the slow-wave structure. The metal block 23 can be a metal quadrangular prism with a trapezoidal cross-section. The bottom surface of the metal quadrangular prism is attached to the top surface of the highest waveguide ridge 22 and is connected to the planar zigzag slow-wave line 12 of the slow-wave structure 10.

[0167] The signal input device 20 provided in the embodiment of the present application uses a waveguide ridge 22 to feed signals (such as microwave signals, millimeter wave signals or signals in the terahertz frequency band). The waveguide ridge 22 is connected to the planar zigzag slow wave line 12 of the slow wave structure 10 through a metal block 23, and can effectively complete the conversion of the electric field mode from the TE10 mode to the quasi-TE10 mode, that is, complete the mode conversion from the standard waveguide to the slow wave structure.

[0168] Optionally, the materials of the waveguide ridge 22 and the metal block 23 may be the same or different, for example, they may be made of metal materials such as copper, stainless steel, aluminum, and silver.

[0169] As shown in Figures 11 and 12, in the embodiment of the present application, the signal output device 30 has the same structure as the signal input device 20. Through the above arrangement, while achieving better impedance matching with the slow-wave structure 10, it can also improve the versatility of the signal output device 30 and the signal input device 20. During installation, there is no need to distinguish between the signal output device 30 and the signal input device 20, which can improve assembly efficiency.

[0170] On the other hand, the present invention also provides a communication device. Figure 13 is a schematic diagram of a modular structure of an example of the communication device provided by the present invention. As shown in Figure 13, the communication device provided by the present invention includes the traveling wave tube 100 provided by the above embodiment.

[0171] Since the communication device adopts the traveling wave tube 100 provided in the above embodiment, the communication device also has the technical effects corresponding to the traveling wave tube 100, which will not be described in detail here.

[0172] Optionally, as shown in FIG13 , the communication device provided in the embodiment of the present application may further include an antenna 200 disposed in the housing 400 , and the antenna 200 is connected to the signal output end of the traveling wave tube 100 . The signal amplified by the traveling wave tube 100 may be transmitted by the antenna 200 .

[0173] For example, the antenna 200 may be a horizontal half-wave dipole antenna, a vertical monopole antenna, a Winton antenna, a Yagi antenna, or a dish antenna, but is not limited thereto.

[0174] Optionally, as shown in Figure 13, the communication device provided in the embodiment of the present application may also include a processor 300 disposed in the shell 400, and the processor 300 is connected to the signal input end of the traveling wave tube 100, and the processor 300 is used to generate an electromagnetic signal for amplification by the traveling wave tube 100.

[0175] Optionally, the communication device provided in the embodiment of the present application can be any wired or wireless communication device such as a base station (such as a 5G base station), a radar (such as a millimeter wave radar or a microwave radar), a vehicle-mounted device or a satellite-mounted device.

[0176] FIG14 is a schematic diagram of a modular structure of another example of a communication device provided in an embodiment of the present application. As shown in FIG14 , the communication device provided in an embodiment of the present application includes a housing 400 and the slow-wave structure 10 provided in the aforementioned embodiment, wherein the slow-wave structure 10 is located within the housing 400.

[0177] Since the communication device adopts the slow-wave structure 10 provided in the above embodiment, the communication device also has the technical effects corresponding to the slow-wave structure 10 , which will not be described in detail here.

[0178] Similarly, the communication equipment provided in this embodiment can be any wired or wireless communication equipment such as a base station (such as a 5G base station), a radar (such as a millimeter wave radar or a microwave radar), a vehicle-mounted device or a satellite-mounted device.

[0179] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A slow-wave structure, characterized in that: include: A conductive shell (11) having a vacuum shielding cavity (11a) therein; A plane zigzag slow-wave line (12) is located in the vacuum shielding cavity (11a), and the plane zigzag slow-wave line (12) is a periodically folded metal strip line located in the same plane and extending along the transmission direction (z) of the electron beam; An insulating structural member, used for fixedly suspending the planar meandering slow-wave line (12) in the vacuum shielding cavity (11a); A metal ridge (14) is protrudingly provided on at least one inner surface of the conductive shell (11) opposite to the planar meandering slow-wave line (12).

2. The slow-wave structure according to claim 1, characterized in that The slow-wave structure comprises a plurality of planar meandering slow-wave lines (12), which are sequentially stacked and spaced apart in a thickness direction (y) perpendicular to a transmission direction (z) of an electron beam.

3. The slow-wave structure according to claim 1 or 2, characterized in that: The insulating structural member comprises a plurality of insulating dielectric rods (13), which are distributed on both sides of the planar meandering slow-wave line (12) and are used to suspend the planar meandering slow-wave line (12) in the vacuum shielding cavity (11a) by clamping.

4. The slow-wave structure according to claim 3, characterized in that The metal ridges (14) are provided on the two inner surfaces of the conductive shell (11) opposite to the planar zigzag slow-wave line (12), and the inner edges of the insulating dielectric rods (13) located on both sides of the planar zigzag slow-wave line (12) extend between the two metal ridges (14).

5. The slow-wave structure according to claim 3 or 4, characterized in that: The plane meandering slow-wave line (12) has a folding vertex, and the insulating dielectric rod (13) abuts against the folding vertex.

6. The slow-wave structure according to any one of claims 1 to 5, characterized in that: The plane meandering slow wave line (12) is divided into a plurality of segments along the transmission direction (z) of the electron beam, each of the segments includes a plurality of folding periods, the period lengths of all folding periods in each segment are the same, and the period lengths of adjacent segments are different, wherein the period length is the length of the folding period in the transmission direction (z) of the electron beam.

7. The slow-wave structure according to claim 2, characterized in that The gap between two adjacent plane meandering slow-wave lines (12) constitutes a transmission channel (S) for electron beams, and / or the gap between the metal ridge piece (14) and the plane meandering slow-wave line (12) constitutes a transmission channel (S) for electron beams.

8. The slow-wave structure according to any one of claims 1 to 7, characterized in that: The vacuum shielding chamber (11a) is a rectangular parallelepiped structure, and the transmission direction (z) of the electron beam is parallel to the long side of the rectangular parallelepiped structure.

9. The slow-wave structure according to any one of claims 1 to 8, characterized in that: The slow-wave structure comprises two planar meandering slow-wave lines (12), and the planes where the two planar meandering slow-wave lines (12) are located are parallel to each other and are arranged in mirror symmetry with each other.

10. The slow-wave structure according to any one of claims 1 to 9, characterized in that: The plane meandering slow wave line (12) is in a V-shaped, U-shaped or N-shaped periodic folding shape.

11. The slow-wave structure according to any one of claims 1 to 10, characterized in that: The metal ridge piece (14) is a long strip-shaped sheet structure extending along the transmission direction (z) of the electron beam.

12. The slow-wave structure according to any one of claims 1 to 11, characterized in that: The material of the metal ridge piece (14) includes at least one of copper, aluminum, silver and stainless steel.

13. The slow-wave structure according to any one of claims 3 to 5, characterized in that: The insulating dielectric rod (13) is a long straight column extending along the transmission direction (z) of the electron beam.

14. A traveling wave tube, characterized in that: include: Signal input device (20); Signal output device (30); The slow-wave structure according to any one of claims 1 to 11, wherein the slow-wave structure is connected to the signal input device (20) and the signal output device (30).

15. The traveling wave tube according to claim 14, characterized in that: The signal input device (20) comprises: Rectangular waveguide (21); A plurality of waveguide ridges (22) are provided on the inner surface of the rectangular waveguide (21), the plurality of waveguide ridges (22) are connected in sequence and their heights gradually increase to form a stepped structure, and the highest waveguide ridge (22) among the plurality of waveguide ridges (22) is connected to the slow-wave structure.

16. The traveling wave tube according to claim 15, characterized in that The signal input device (20) further comprises a metal block (23) connecting the waveguide ridge (22) and the slow-wave structure.

17. The traveling wave tube according to claim 16, characterized in that: The metal block (23) is a metal quadrangular prism with a trapezoidal cross section, and the bottom surface of the metal quadrangular prism is attached to the top surface of the highest waveguide ridge (22).

18. The traveling wave tube according to any one of claims 14 to 17, characterized in that: The signal output device (30) has the same structure as the signal input device (20).

19. A communication device, characterized in that: The communication device comprises: A traveling wave tube according to any one of claims 14 to 18.

20. The communication device according to claim 19, wherein The communication device further includes: An antenna (200) is connected to the signal output end of the traveling wave tube.

21. The communication device according to claim 19 or 20, characterized in that The communication device further includes: A processor (300) is connected to the signal input end of the traveling wave tube.

22. A communication device, characterized in that: include: Housing (400); The slow-wave structure according to any one of claims 1 to 13, wherein the slow-wave structure is located within the housing (400).

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