Slow-wave structure, high-frequency system, traveling wave tube and communication device

Abstract

A slow wave structure, a high frequency system, a traveling wave tube and a communication device, the slow wave structure comprises a waveguide, a medium support assembly, and N slow wave bands arranged in sequence along a signal transmission direction, N being a positive integer greater than or equal to 2; every two adjacent slow wave bands are arranged at intervals through a cut-off gap, and the waveguide serves as the ground to surround the N slow wave bands; along the signal transmission direction, one end, far away from the Nth slow wave band, of the first slow wave band is provided with an input port, and one end, far away from the first slow wave band, of the Nth slow wave band is provided with an output port; one end, close to the corresponding cut-off gap, of each slow wave band is connected with a concentrated attenuator, and the concentrated attenuators can reduce signal reflection of the slow wave bands at the corresponding cut-off gaps, absorb reflected signals and suppress backward wave oscillation and reflected oscillation of the traveling wave tube; and each centralized attenuator is located outside the cut-off gap and does not occupy the space in the cut-off gap, so that miniaturization is realized while high gain and high electronic efficiency are ensured.

Description

Slow-wave structure, high-frequency system, traveling wave tube and communication device Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a slow-wave structure, a high-frequency system, a traveling wave tube, and a communication device. Background Art

[0002] As mobile communications gradually evolve towards millimeter-wave and even submillimeter-wave frequency bands, the development goals of wide bandwidth, miniaturization, and high stability place higher demands on the overall performance and structural dimensions of various components. Traveling-wave tubes (TWTs), as vacuum electronic amplifiers, inherently offer high power, high gain, and high efficiency. However, compared to solid-state amplifiers, existing TWT amplifiers still suffer from large size and weight, difficulties in mass production and integration, and long production cycles. Therefore, to meet the future development needs of TWT amplifiers in mobile communications, miniaturized and integrable planar TWTs have become an important development direction. Furthermore, TWTs typically serve as the final amplifier in communication systems. On the one hand, the structural dimensions of TWTs are directly related to their performance, such as output power, gain, bandwidth, and efficiency; on the other hand, the overall dimensions of TWTs also have a significant impact on the system's volume and weight. Therefore, exploring new, miniaturized, and highly stable planar TWTs is crucial for achieving TWT miniaturization and mass production.

[0003] The high-frequency system includes a slow-wave structure, an input coupler, and an output coupler. As the core component of the traveling wave tube energy conversion, it directly determines the overall performance of the device. In particular, the device's structural characteristics and electromagnetic characteristics, such as structural size, power level, bandwidth, electronic efficiency, and gain, are directly determined by the electromagnetic characteristics of the high-frequency system.

[0004] As the most widely used vacuum amplifier, traveling wave tubes are gradually developing towards the millimeter wave to terahertz frequency band. For example, traveling wave tubes use a waveguide-type high-frequency system. This high-frequency system has a large structure and size, which is convenient for machining using processes such as cutting, milling and turning. It is convenient to connect with the waveguide in the millimeter wave to terahertz frequency band and is easy to match with external circuits. However, its interaction impedance is low, and high processing and assembly precision are required. It is also difficult to achieve miniaturization.

[0005] Folded-line high-frequency systems, however, utilize dielectric loading, are suitable for micro-addition processes, and offer broadband, planarization, and strip-shaped beamforming. Due to their low coupling impedance and high loss characteristics, achieving high gain requires replacing part of the slow-wave line's dielectric substrate with a lossy material, disrupting the transmission path of the electromagnetic wave and attenuating it, thereby suppressing oscillations. This presents two major challenges: First, given a given attenuation coefficient, achieving sufficient attenuation requires increasing the attenuator's size, particularly its length. This increased length affects electron beam clustering, reducing interaction efficiency and gain. Second, the attenuator absorbs electromagnetic waves transmitted from the input port or reflected from the output port, converting the electromagnetic energy into heat. This requires ensuring sufficient attenuation, which also increases the attenuator's size and impacts the TWT's gain and electronic efficiency.

[0006] None of the above solutions can achieve high gain and high electronic efficiency while taking into account miniaturization.

[0007] As an important component of the high-frequency system, the slow-wave structure is severely restricted by the structural size and related performance of the high-frequency system.

[0008] Summary of the Invention

[0009] The present application provides a slow-wave structure, a high-frequency system, a traveling wave tube, and a communication device for achieving high gain and high electronic efficiency while taking into account miniaturization.

[0010] In a first aspect, a slow-wave structure is provided, which includes: a waveguide, a dielectric support component, and N slow-wave bands arranged in sequence along a signal transmission direction, wherein N is a positive integer greater than or equal to 2; every two adjacent slow-wave bands are spaced apart by a truncation gap, and the isolation between adjacent slow-wave bands is increased, the waveguide serves as a ground surrounding the N slow-wave bands, and the N slow-wave bands are supported on the waveguide by the dielectric support component; along the signal transmission direction, the first slow-wave band has an input port for feeding a signal at one end away from the Nth slow-wave band, and the Nth slow-wave band is away from the first slow-wave band. One end of the slow-wave band has an output port for outputting signals; one end of each slow-wave band close to the corresponding truncation gap is connected to a centralized attenuator, which can reduce the signal reflection of the slow-wave band at the corresponding truncation gap and absorb the reflected signal from the input port or the output port, thereby suppressing the return wave oscillation and reflection oscillation of the traveling wave tube; in addition, each centralized attenuator is located outside the truncation gap and does not occupy the space in the truncation gap. While pursuing the power capacity and attenuation of the centralized attenuator, its volume is increased, ensuring the high gain and high electronic efficiency of the traveling wave tube while still achieving the miniaturization of the slow-wave structure.

[0011] In a specific possible implementation scheme, each of the concentrated attenuators includes a lead-out conductor and a lossy medium. The lead-out conductor is connected to the corresponding slow-wave band and contacts the lossy medium, leading the signal of the corresponding slow-wave band to the lossy medium. The backward oscillation signal and the reflected signal are attenuated by the lossy medium to suppress the backward oscillation and the reflected oscillation, thereby ensuring the stable operation of the traveling wave tube.

[0012] In a specific possible implementation scheme, the lossy medium is in a plate shape, and the lead conductor is a planar structure extending along a plane of the lossy medium, so as to increase the contact area, fully attenuate the signal, and save space.

[0013] In a specific possible implementation scheme, the lead conductor is a metal patch, which is easy to form by etching a circuit, has good stability, and has a large contact area with the lossy medium.

[0014] In a specific possible implementation scheme, the width of each metal patch increases in a step-like manner in a direction away from the corresponding slow-wave band, so as to achieve impedance matching with the corresponding slow-wave band and reduce reflection.

[0015] In a specific possible implementation scheme, the lead conductor is a metal wire with a redundant structure. The redundant structure is utilized to fully attenuate the signal while reducing the occupied space.

[0016] In a specific embodiment, the redundant structure is a periodically extended waveform structure to stably attenuate signals.

[0017] In a specific possible implementation scheme, each of the concentrated attenuators is located in the space enclosed by the waveguide, and the waveguide can be used to physically protect the concentrated attenuator. The lead-out conductor is spaced apart from the inner wall of the waveguide by the loss medium, thereby improving the fixing effect, reducing the occupied space, and alleviating the problem of direct contact between the lead-out conductor and the waveguide.

[0018] In a specific possible implementation scheme, the lossy medium is embedded in the inner wall of the waveguide, which increases the contact area, is beneficial to heat dissipation, and is beneficial to improving the fixing effect.

[0019] In a specific possible implementation scheme, each of the concentrated attenuators is located outside the waveguide to reduce the internal space occupied, and the lead conductor is spaced apart from the outer wall of the waveguide by the lossy medium to alleviate the problem of direct contact between the lead conductor and the waveguide.

[0020] In a specific possible implementation scheme, the lead conductor is linear, and the linear lead conductor is fully wrapped by the lossy dielectric, thereby having a relatively stable attenuation effect.

[0021] In one specific embodiment, each concentrated attenuator comprises a coaxial cable comprising, from the inside out, an inner core, a lossy dielectric layer, and an outer conductor layer, wherein the inner core forms the lead conductor, and the lossy dielectric layer forms the lossy dielectric. This allows for direct use of readily available coaxial cables for concentrated attenuation, making parts readily available.

[0022] In a specific possible implementation manner, each of the concentrated attenuators extends in a direction perpendicular to the side wall of the waveguide and penetrates the waveguide, thereby reducing the space occupied inside the waveguide.

[0023] In a specific embodiment, the loss tangent of the lossy medium is greater than 0.1 to sufficiently attenuate the signal.

[0024] In a specific feasible implementation scheme, each of the slow-wave bands includes multiple layers of slow-wave lines spaced apart in a longitudinal direction, and power combiners corresponding one-to-one to the concentrated attenuators, wherein the longitudinal direction is perpendicular to the signal transmission direction; each layer of the slow-wave lines extends in the same plane, and the slow-wave lines in each two adjacent slow-wave bands correspond one-to-one, and the multiple layers of the slow-wave lines are connected to the corresponding concentrated attenuators through one power combiner to simplify the number of attenuators, simplify the structure, and reduce the space occupied inside the waveguide.

[0025] In one specific embodiment, the slow-wave lines in each layer are periodically extended waveforms. The distance D between each pair of adjacent slow-wave segments satisfies the following: 2*P2≤D≤5*P1, where P1 represents the length of a single cycle of the slow-wave line in the upstream slow-wave segment, and P2 represents the length of a single cycle of the slow-wave line in the downstream slow-wave segment. If the distance D is too large, the slow-wave structure will be too long. If the distance D is too small, the isolation between adjacent slow-wave segments will be too small.

[0026] In a specific possible implementation scheme, the dielectric support assembly includes dielectric support rods arranged on both sides of each slow-wave band in the width direction, wherein the width direction is perpendicular to the signal transmission direction and the longitudinal direction; the two side edges of each layer of the slow-wave line in the width direction are respectively connected to the dielectric support rods on the corresponding sides to achieve stable support.

[0027] In a specific possible implementation scheme, the waveguide includes two longitudinal side walls arranged opposite to each other along the width direction, and two transverse side walls connecting the two longitudinal side walls; each of the dielectric support rods is connected to the transverse side walls on both sides of the longitudinal direction for fixation and heat dissipation, and the two side edges of each layer of the slow-wave line in the width direction are respectively embedded in the dielectric support rods on the corresponding sides to increase the contact area and improve the heat dissipation effect.

[0028] In a specific possible implementation scheme, a metal ridge is provided in the middle of each of the lateral side walls; wherein each of the dielectric support rods is filled in the space between the two metal ridges and the longitudinal side wall on a corresponding side, thereby improving the fixing effect of the dielectric support rod, increasing the contact area with the waveguide, and improving the heat dissipation efficiency; or, each of the dielectric support rods is clamped between the two metal ridges and connected to a corresponding longitudinal side wall, thereby better fixing the dielectric support rod in the longitudinal direction and abutting against the longitudinal side wall in the width direction, thereby improving the fixing stability; or, each of the dielectric support rods includes two support portions spaced apart along the longitudinal direction, and the two support portions are connected one-to-one to the two lateral side walls, respectively, thereby widening the space of the electron beam in the width direction and improving the output efficiency.

[0029] In a specific feasible implementation scheme, a metal ridge is provided in the middle of each of the lateral side walls; the two dielectric support rods are respectively embedded in the longitudinal side walls on the corresponding sides, which is conducive to fixation and heat dissipation, and each of the dielectric support rods has a certain gap between the two end faces in the longitudinal direction and the metal ridge on the corresponding side; the two outermost layers of slow-wave lines in each slow-wave band in the longitudinal direction are respectively flush one-to-one with the two end faces in the longitudinal direction of each dielectric support rod, alleviating the problem of direct contact between the slow-wave line and the metal ridge.

[0030] In a specific feasible implementation scheme, the input port is connected to the multiple layers of the slow-wave lines of the first slow-wave band through a power divider; along the signal transmission direction, the power divider and the adjacent power combiner clamp one of the dielectric support rods corresponding to the first slow-wave band between the two, and each of the remaining two adjacent power combiners clamps a corresponding dielectric support rod between the two to fix the dielectric support rod in the signal transmission direction.

[0031] In a specific possible implementation scheme, each of the concentrated attenuators is located on the side of a corresponding dielectric support rod away from the corresponding slow-wave band, and cooperates with the slow-wave band to clamp the dielectric support rod therebetween, so as to improve the fixing effect of the slow-wave band and the dielectric support rod.

[0032] In a specific possible implementation scheme, when the lead conductor is spaced apart from the inner wall of the waveguide through the lossy medium and the lead conductor is the planar structure, the planar structure contacts the dielectric support rod, and the dielectric support rod is used to further improve the signal attenuation effect.

[0033] In a specific possible implementation scheme, each of the slow-wave lines includes two layers of slow-wave lines, and each layer of the slow-wave line is spaced from the inner wall of the corresponding side of the waveguide by a dielectric substrate, thereby supporting the slow-wave line while occupying a smaller space inside the waveguide.

[0034] A second aspect provides a high-frequency system comprising an input coupler, an output coupler, and a slow-wave structure according to any of the above technical solutions. The input coupler is connected to the input port to feed a signal into the input port, and the output coupler is connected to the output port to output the signal through the output coupler. Because the slow-wave structure can achieve miniaturization while maintaining high gain and high electronic efficiency of a traveling wave tube, the high-frequency system has similar effects.

[0035] Thirdly, a traveling wave tube (TWT) is provided, comprising: an electronic transceiver assembly, a focusing assembly, and the high-frequency system. The electronic transceiver assembly is configured to transmit electrons along the signal transmission direction throughout each slow-wave band, and the focusing assembly is configured to focus the electrons into an electron beam. The electron beam transfers energy to electromagnetic waves in the slow-wave band, amplifying the signal, and the electromagnetic waves in the slow-wave band modulate the electron beam. Furthermore, the high-frequency system employing the above-described technical solution, as the core transducer component of the TWT, facilitates miniaturization of the slow-wave structure while ensuring high gain and high electronic efficiency.

[0036] In a fourth aspect, a communication device is provided. The communication device may be a base station or an in-vehicle device, comprising an upstream external circuit, a downstream external circuit, and the traveling wave tube described in the above technical solution. The upstream external circuit is connected to the input coupler to feed a signal into the traveling wave tube, and the downstream external circuit is connected to the output coupler to receive the signal amplified by the traveling wave tube. This communication device can achieve high performance in a compact size. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG1 shows the overall architecture of a traveling wave tube provided in an embodiment of the present application;

[0038] FIG2 a shows a schematic structural diagram of a traveling wave tube medium-high frequency system provided in an embodiment of the present application;

[0039] FIG2b shows a cross-sectional view taken along line AA of the high-frequency system shown in FIG2a;

[0040] FIG2 c is a schematic diagram showing the internal structure of the high-frequency system shown in FIG2 a after removing the waveguide;

[0041] FIG2 d is a schematic diagram showing the structure shown in FIG2 c in conjunction with a metal ridge of a waveguide;

[0042] FIG2e is a schematic diagram showing the structure shown in FIG2c after removing the lossy dielectric substrate 322b;

[0043] FIG2f shows a partial enlarged view of point B in FIG2e;

[0044] FIG2g shows a schematic diagram of the centralized attenuator 322 in FIG2c;

[0045] FIG2h shows the S-parameter simulation diagram of the traveling wave tube corresponding to FIG2a to FIG2g;

[0046] FIG2i is a schematic diagram showing the change of the power flow of the slow-wave structure 30 along the signal propagation direction Y in the high-frequency system shown in FIG2a to FIG2g;

[0047] FIG2j shows a comparison of the output power of the traveling wave tube corresponding to FIG2a to FIG2g and the output power of a conventional traveling wave tube;

[0048] Figure 3a shows a variation of the structure shown in Figure 2b;

[0049] FIG3b shows a variation of the structure shown in FIG3a;

[0050] FIG3c shows another variation of the structure shown in FIG3a;

[0051] FIG4 a shows a schematic structural diagram of another traveling wave tube medium and high frequency system provided in an embodiment of the present application;

[0052] FIG4b shows a front view of the high frequency system shown in FIG4a;

[0053] FIG4c is a cross-sectional view of the high-frequency system shown in FIG4b taken along the FF direction;

[0054] FIG4 d is a schematic diagram showing the structure of the high-frequency system shown in FIG4 a after removing the waveguide;

[0055] FIG4e shows a partial enlarged view of point C in FIG4d;

[0056] FIG5 a shows a schematic structural diagram of another traveling wave tube medium and high frequency system provided in an embodiment of the present application;

[0057] FIG5b shows a cross-sectional view taken along the EE direction in FIG5a;

[0058] FIG5c shows a Z-direction view of the structure shown in FIG5b;

[0059] FIG5 d shows a view of the structure shown in FIG5 b along the negative direction of the X-axis;

[0060] FIG6 is a schematic diagram showing a partial structure of a communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solutions and advantages of this application clearer, this application will be further described in detail below with reference to the accompanying drawings.

[0062] To facilitate understanding of the traveling wave tube provided in the embodiments of this application, let's first explain its application scenarios. This traveling wave tube can be used in communication devices such as base stations and vehicle-mounted devices to perform final-stage amplification of electromagnetic wave signals. For example, an upstream external circuit feeds a signal into the traveling wave tube, which amplifies the signal before feeding it into a final-stage antenna. This traveling wave tube can function as a microwave source or amplifier.

[0063] Figure 1 shows the overall architecture of the traveling wave tube provided in an embodiment of the present application. In order to have an overall understanding of the traveling wave tube provided in an embodiment of the present application, its architecture is described below with reference to Figure 1. However, it should be understood that Figure 1 does not represent the actual structural diagram of the traveling wave tube, and the details in the architecture do not constitute a limitation on the scope of the embodiment of the present application.

[0064] The traveling wave tube includes a waveguide 50, a focusing component 10, an electronic transceiver component 20, a slow-wave structure 30, an input coupler M1 and an output coupler M2, wherein the waveguide 50, the input coupler M1 and the output coupler M2 belong to the high-frequency system in the traveling wave tube, and the focusing component 10 is located outside the waveguide 50 and can be arranged around the waveguide 50 or on two opposite sides of the waveguide 50 in the Z direction. For details, please refer to Figure 2b mentioned later. The slow-wave structure 30 includes an input slow-wave band 31 and an output slow-wave band 32 arranged at intervals along the signal transmission direction Y. The input slow-wave band 31 and the output slow-wave band 32 both extend along the signal transmission direction Y, and a truncation gap G is formed between the two. The slow-wave structure 30 is formed into the above-mentioned input slow-wave band 31 and the output slow-wave band 32 by truncation of the truncation gap G; and the waveguide 50 includes a waveguide tube body, which surrounds the input slow-wave band 31 and the output slow-wave band 32, or in other words, the input slow-wave band 31 and the output slow-wave band 32 are arranged in the waveguide tube body along the axial direction of the waveguide tube body. The input slow-wave band 31 includes n layers of slow-wave lines spaced apart in sequence, where n is a positive integer, such as 1, 2, 3, 4, 5, 6, or 7. Each layer of slow-wave lines extends in the same plane. When n ≥ 2, the slow-wave lines in different layers are parallel to each other. FIG1 exemplarily illustrates only the outermost slow-wave lines T1 and Tn. Slow-wave lines T1 through Tn are all connected to a centralized attenuator 312 at their ends near the output slow-wave band 32 (i.e., the terminal end of the input slow-wave band 31) via a power combiner 311. Similarly, the output slow-wave band 32 includes n layers of slow-wave lines spaced apart in sequence, namely, slow-wave lines R1 through Rn. Slow-wave lines R1 through Rn correspond one-to-one with slow-wave lines T1 through Tn. Each layer of slow-wave lines is connected to a centralized attenuator 322 at its ends near the input slow-wave band 31 (i.e., the terminal end of the output slow-wave band 32) via a power combiner 321. The concentrated attenuator 312 and the concentrated attenuator 322 are both distributed in the area outside the truncation gap G, or in other words, in the signal transmission direction Y, the projections of the concentrated attenuator 312 and the concentrated attenuator 322 do not overlap with the projections of the input slow band 31 and the output slow band 32 respectively.

[0065] The input slow-wave band 31 has an input port at one end away from the output slow-wave band 32, and the output slow-wave band 32 has an output port at one end away from the input slow-wave band 31, for outputting the signal to the downstream external circuit. The input coupler M1 is connected to the input port for feeding in the signal and inputting the power, and the output coupler M2 is connected to the output port for coupling the amplified high-frequency signal to the downstream external circuit, which can specifically be an antenna. Specifically, a power divider can be used to connect the input coupler M1 to the slow-wave lines T1 to Tn, respectively, and transmit the fed signal to the slow-wave lines T1 to Tn, respectively. The function of the power divider is to reduce the number of input ports, simplify the circuit structure, reduce the number of input couplers, and use one input port to meet the signal feeding work of multiple slow-wave lines, thereby reducing the space occupied by the internal waveguide body; and through a power combiner, the slow-wave lines R1 to Rn are connected to the output coupler M2 for signal connection, and the signals of the slow-wave lines R1 to Rn are concentrated to the output coupler M2. The input coupler M1 and the output coupler M2 may both be in the form of coaxial cables or waveguide couplers.

[0066] The electron transceiver assembly 20 includes an electron gun 21 and a collector 22, which are arranged on either side of the slow-wave structure 30 along the signal transmission direction Y. The electron gun 21 emits electrons throughout each slow-wave band toward the collector 22 along the signal transmission direction Y. The focusing assembly 10 is used to bunch the electrons emitted by the electron gun 21 into an electron beam 201, alleviating the problem of excessive divergence of the electron beam 201. The bunched electron beam 201 sequentially passes through the input slow-wave band 31 and the output slow-wave band 32 along the signal transmission direction Y and reaches the collector 22. The focusing assembly 10 can specifically adopt a magnetic focusing assembly, but is not limited to a magnetic focusing assembly, as long as it can bunch the electrons emitted by the electron gun 21 into the electron beam 201.

[0067] When the traveling wave tube performs signal amplification, the slow wave structure 30 is fed with a signal by the input coupler M1, and the signal is transmitted along the signal transmission direction Y in the input slow wave band 31; the signal in the input slow wave band 31 interacts with the electron beam 201, and the electron beam 201 is modulated by the input electromagnetic wave. The electron beam 201 forms a cluster along the interaction direction (i.e., the signal transmission direction Y) and gradually gives up energy, converting the kinetic energy of the electron beam 201 into microwave energy to amplify the signal; specifically, the electron beam 201 is connected from any two adjacent slow wave lines (such as T1) in each slow wave band. and T2, or, R1 and R2), the electron beam 201 may also pass between every two slow-wave lines, or pass through the gaps between some slow-wave lines, interact with the electric field on the slow-wave line, convert the energy of the electron beam 201 into electromagnetic wave energy, and couple it into the slow-wave line, thereby achieving signal amplification; after the input slow-wave band signal is transmitted to its terminal position, it reaches the centralized attenuator 312, which can reduce the signal reflection at the terminal position of the input slow-wave band 31 and absorb the reflected signal from the input port of the input slow-wave band 31. Since the electron beam 201 has been modulated by the electromagnetic wave in the input slow-wave band 31 and loaded with the signal therein, the electron beam 201 couples the loaded signal to the output slow-wave band 32. Similarly, the signal in the output slow-wave band 32 also interacts with the electron beam 201. The electron beam 201 uses its own energy to amplify the signal in the output slow-wave band 32. Finally, the output slow-wave band 32 transmits the signal to the output port and outputs it to the downstream external circuit through the output coupler M2. The concentrated attenuator 322 can reduce the signal reflection at the terminal position of the output slow-wave band 32 and absorb the reflected signal from the output port of the output slow-wave band 32. The concentrated attenuator 312 and the concentrated attenuator 322 work together to suppress the traveling wave tube's backward oscillation and reflection oscillation, thereby solving the stability problem caused by self-excited oscillation during the traveling wave tube's signal amplification process. The electron beam 201 is finally collected by the collector 22.

[0068] Since the concentrated attenuator 312 and the concentrated attenuator 322 are both located in the area outside the truncation gap G and do not occupy the space in the truncation gap G, while increasing the volume of the concentrated attenuator 312 and the concentrated attenuator 322 in pursuit of the power capacity and attenuation, it is still convenient to achieve the miniaturization of the entire slow-wave structure 30, while ensuring the high gain and high electronic efficiency of the traveling wave tube, the smaller length of the slow-wave structure 30 can be taken into account; moreover, the concentrated attenuator 312 and the concentrated attenuator 322 avoid the interaction area between the electron beam 201 and the electromagnetic wave of the slow-wave structure 30, thereby reducing to a certain extent the charge accumulation problem caused by the electron beam 201 bombarding the lossy medium therein.

[0069] To more clearly understand the structure of the traveling wave tube provided in an embodiment of the present application, FIG2a shows a schematic diagram of the structure of a high-frequency system in a traveling wave tube provided in an embodiment of the present application. FIG2b shows a cross-sectional view taken along the AA axis of the high-frequency system shown in FIG2a. FIG2c shows a schematic diagram of the internal structure of the high-frequency system shown in FIG2a after the waveguide is removed. In conjunction with FIG2a and FIG2c, waveguide 50 is exemplarily a rectangular waveguide having a rectangular cross-section. The waveguide body specifically includes transverse sidewalls 52a, 52b, longitudinal sidewalls 51a, and 51b. Transverse sidewalls 52a and 52b extend parallel to the XOY plane and are arranged opposite each other along the longitudinal direction Z. Longitudinal sidewalls 51a and 51b are arranged on either side of transverse sidewalls 52a and 52b along the width direction X and connect transverse sidewalls 52a and 52b. In the rectangular cross-section of the waveguide body, longitudinal sidewalls 51a and 51b are relatively small, forming the narrow sides of the rectangular waveguide. Transverse sidewall 52a has an inner side surface facing transverse sidewall 52b. A plate-shaped metal ridge 53a is provided in the middle of the inner side surface of transverse sidewall 52b. Correspondingly, a metal ridge 53b is also provided in the middle of the inner side surface of transverse sidewall 52b. Metal ridges 53a and 53b are arranged opposite each other along the longitudinal direction Z. The function of metal ridge 53a is to increase the capacitance between slow-wave lines (such as T1 and R1) and the ground (waveguide 50), thereby reducing dispersion. Metal ridge 53b has a similar function. Furthermore, to illustrate the coordination relationship between focusing assembly 10 and other components, the position of focusing assembly 10 is shown in FIG2b . This is not shown in other structurally related drawings, but the focusing assembly 10 still has similar coordination relationships.

[0070] However, it should be understood that the actual shape of the waveguide 50 is not limited to a rectangle, and may be a waveguide of other shapes. In particular, when the shape of the internal components of the waveguide 50 changes, a circular waveguide or other waveguide may be used.

[0071] In addition, the waveguide 50 includes end walls 54a and 54b. End walls 54a and 54b are disposed one-to-one with the openings at both ends of the waveguide body in the signal transmission direction Y. Together with the waveguide body, they form a sealed space to maintain a vacuum environment within the interior space enclosed by the waveguide 50. Furthermore, all components of the waveguide 50 are constructed of metal, such as oxygen-free copper, aluminum, and stainless steel, to serve as a ground for the internal structure of the waveguide 50. Specifically, the electron gun 21 can be mounted by opening a hole in the end wall 54a, and the collector 22 can be mounted by opening a hole in the end wall 54b.

[0072] The input slow wave band 31 specifically includes two layers of slow wave lines T1 and slow wave lines T2 that are spaced apart in sequence along the longitudinal direction Z. Both the slow wave lines T1 and T2 extend along a plane parallel to the lateral side wall 52a. It should be understood that in the embodiment of the present application, "parallel" can be strictly parallel or approximately parallel, that is, errors allowed in engineering are allowed; the slow wave line T1 can specifically be a folded line type, specifically including a plurality of slow wave units connected in sequence along the signal transmission direction Y, each slow wave unit can be roughly sinusoidal or rectangular, and each slow wave unit constitutes a cycle, but is not limited to the above two waveforms. As long as it is a periodic waveform structure, it is conducive to providing stable signal output. Electron beam 201 passes between slow-wave line T1 and slow-wave line T2. Slow-wave line T1 utilizes a zigzag structure, allowing the actual signal transmission distance to be longer than a straight-line transmission distance. This reduces the propagation speed of the input signal, allowing the electron beam 201 emitted by the electron gun 21 to travel at a speed close to the phase velocity of the electromagnetic wave in slow-wave line T1. This ensures synchronization between the electron beam 201 and the electromagnetic wave, enhancing the interaction between the electron beam 201 and the electromagnetic wave. Consequently, the energy of the electron beam 201 is more efficiently converted into high-frequency electromagnetic energy, while the electromagnetic wave modulates the electron beam 201. Slow-wave line T1 can be made of high-hardness metals such as molybdenum, tungsten, and copper-plated copper. Slow-wave line T2 shares a similar structure and material with slow-wave line T1.

[0073] With specific reference to FIG2b , slow-wave lines T1 and T2 are both positioned in the center of the space enclosed by the waveguide body and are supported in this position by dielectric support rods 61a and 61b, which are arranged on either side in the width direction X. Dielectric support rods 61a are connected to longitudinal sidewalls 51a and may be embedded within longitudinal sidewalls 51a. This facilitates a secure connection with longitudinal sidewalls 51a and increases the contact area between dielectric support rods 61a and longitudinal sidewalls 51a, facilitating sufficient heat dissipation through longitudinal sidewalls 51a. Dielectric support rods 61b are similarly connected to longitudinal sidewalls 51b.

[0074] Figure 2d is a schematic diagram showing the coordination of the structure shown in Figure 2c with the metal ridge of the waveguide. In combination with Figure 2b and Figure 2d, the size of the dielectric support rod 61a in the longitudinal direction Z is smaller than the distance between the metal ridge 53a and the metal ridge 53b, and a certain gap is maintained between the dielectric support rod 61a and the metal ridge 53a and the metal ridge 53b in the longitudinal direction Z; the dielectric support rod 61b is flush with the dielectric support rod 61a in the longitudinal direction Z, alleviating the problem of direct contact with the slow-wave line T1 by the metal ridge 53a, which affects the capacitance between the waveguide 50 and the slow-wave line T1. Other metal ridges and slow-wave lines may not be in direct contact, and the effects are similar.

[0075] The slow-wave line T1 is flush with the surfaces of the dielectric support rods 61a and 61b facing the transverse sidewall 52a. A stepped groove U1 is provided at the corners of the dielectric support rod 61a near the longitudinal sidewall 51b and the transverse sidewall 52a. The slow-wave line T1 overlaps within this stepped groove U1, specifically by bonding to the inner wall of the stepped groove U1, making installation quick and easy. Furthermore, the stepped groove U1 maintains sufficient physical contact with the dielectric support rod 61a through its two inner walls, ensuring effective heat dissipation. The connection between the slow-wave line T1 and the dielectric support rod 61b, the connection between the slow-wave line T2 and the dielectric support rods 61a and 61b, and the connection between the slow-wave lines R1 and R2 and the dielectric support rods 62a and 62b, respectively, all employ the aforementioned method. As shown in FIG2f , the slow-wave line R1 overlaps within the stepped groove U2 of the dielectric support rod 62a.

[0076] Continuing to refer to Figures 2a and 2c, both the input coupler M1 and the output coupler M2 use coaxial cables as coupling structures. In Figure 2c, only the inner cores of the input coupler M1 and the output coupler M2 are shown. The input coupler M1 is specifically connected to the slow-wave line T1 and the slow-wave line T2 through the power divider 313, so as to simplify the circuit structure of the input port, reduce the number of input couplers M1, and facilitate miniaturization. The power divider 313 specifically includes two output branches, which are close to each other and converge to an endpoint. The endpoint is connected to the input coupler M1 as an input endpoint. The ends of the two output branches away from the input endpoint are connected to the slow-wave line T1 and the slow-wave line T2 respectively. This structure can be made of a single metal wire, and the process is simple and easy to implement, with good stability. The structure of the power divider d is not limited to this structure. To optimize impedance matching, an extended conductor serves as an impedance matching segment between the power divider 313 and the slow-wave lines T1 and T2. For example, an impedance matching segment L1 is connected between one of the output branches of the power divider 313 and the slow-wave line T1. Impedance matching segment L1 is also located within the stepped recess U1, thereby strengthening the secure fit between the slow-wave line T1 and the dielectric support rod 61a. The power divider 313 is perpendicularly connected to the impedance matching segment L1, bending toward the end face of the dielectric support rod 61a toward the end wall 54a and extending along that end face. The input coupler M1 extends through the longitudinal side wall 51a in a direction perpendicular to the longitudinal side wall 51a and partially extends beyond the longitudinal side wall 51a to facilitate connection with an upstream external circuit. Similarly, output coupler M2 connects signals to slow-wave line R1 and slow-wave line R2 through power combiner 323. The signals output by slow-wave line R1 and slow-wave line R2 are concentrated and outputted by output coupler M2 through power combiner 323. Power combiner 323 can use two input branches close to each other to form an output endpoint. Slow-wave line R1 and slow-wave line R2 are respectively connected to the two input branches, and the output endpoint is connected to output coupler M2. Other power combiners in the embodiments of the present application can adopt this structure, but are not limited to this structure. Power combiner 323 is located on the end surface of dielectric support rod 62b facing end wall 54b. Power combiner 323 is respectively connected to slow-wave line R1 and slow-wave line R2 through an impedance matching section, such as impedance matching section L2 connecting slow-wave line R1 and an input branch of power combiner 323. Output coupler M2 partially penetrates the longitudinal side wall 51b in a direction perpendicular to longitudinal side wall 51b to the outside of longitudinal side wall 51b, so as to facilitate connection with downstream external circuits. The input coupler M1 and the output coupler M2 are arranged on two opposite longitudinal side walls (51a and 51b) of the waveguide body 50, and the socket directions are opposite. When waveguide couplers are used as the input coupler M1 and the output coupler M2, the problem of mutual interference between the flanges of the waveguide couplers can be alleviated.

[0077] Continuing with reference to Figure 2c, the concentrated attenuator 312 is located on the side of the dielectric support rod 61a facing away from the dielectric support rod 61b. Specifically, it can contact the dielectric support rod 61a and, through the power combiner 311, combine the power of the slow-wave line T1 and the slow-wave line T2 and transmit it to the concentrated attenuator 312. The power combiner 311 can reduce the number of concentrated attenuators 312 used, simplify the internal structure of the waveguide body, and reduce the space occupied by the internal waveguide body. The power combiner 311 extends along the end face of the dielectric support rod 61a away from the power divider 313. Furthermore, a section of wire can be provided between the power combiner 311 and the slow-wave line T1 and the slow-wave line T2 as an impedance matching section to achieve impedance matching. Because the power combiner 311 and the power divider 313 clamp the dielectric support rod 61a in the middle, it is beneficial for the input slow-wave band 31 to achieve a stable connection with the dielectric support rod 61a in the signal transmission direction Y. Specifically, the slow-wave line T1, the slow-wave line T2, the power combiner 311 and the power divider 313 can be manufactured as a whole, for example, by bending the metal wire in one step, which is conducive to enhancing the structural stability; or, the slow-wave line T1 and the slow-wave line T2 can be prepared separately and welded to the power combiner 311 and the power divider 313 respectively to reduce the process difficulty.

[0078] Similarly, the concentrated attenuator 322 is located on the side of the dielectric support rod 62b away from the dielectric support rod 62a, and the slow-wave lines R1 and R2 are connected to the concentrated attenuator 322 through the power combiner 321. The power combiner 322 and the power combiner 323 sandwich the dielectric support rod 62b to improve the connection stability.

[0079] It should be understood that when the slow-wave structure 30 includes more than three slow-wave bands, for the other slow-wave bands between the input slow-wave band 31 and the output slow-wave band 32, the power combiners at both ends of each slow-wave band also clamp a dielectric support rod corresponding to the slow-wave band in the middle to improve the combination stability.

[0080] In addition, since the concentrated attenuator 312 and the concentrated attenuator 322 are distributed on both sides of the traveling wave tube in the width direction X, the interference between the two due to their proximity is reduced, and it is beneficial to achieve the force balance of the input slow wave band 31 and the output slow wave band 32 on the waveguide body in the width direction X, and it is beneficial to achieve the centering of the input slow wave band 31 and the output slow wave band 32.

[0081] Figure 2e shows a schematic diagram of the structure shown in Figure 2c after the lossy dielectric substrate 322b is removed. Figure 2f shows an enlarged view of a portion B in Figure 2e. Figure 2g shows a schematic diagram of the concentrated attenuator 322 in Figure 2c. The concentrated attenuator 322 comprises a lossy dielectric substrate 322b and a metal patch 322a. The metal patch 322a is attached to the lossy dielectric substrate 322b and connected to the output terminal of the power combiner 321. The metal patch 322a can be made of a metal material such as oxygen-free copper, aluminum, or stainless steel. Specifically, a metal circuit can be etched on the lossy dielectric substrate 322b to form the metal patch. The lossy dielectric substrate 322b can be made of a high-loss dielectric material, specifically a vacuum dielectric material with a high loss ratio, including but not limited to silicon carbide, metal attenuation porcelain, and carburized porous ceramic. The backward oscillation signal and reflected signal generated during operation of the slow-wave band 32 are transmitted to the metal patch 322a and rapidly attenuated by the lossy dielectric substrate 322b, thereby suppressing the backward oscillation and reflected oscillation and ensuring stable operation of the traveling wave tube. With specific reference to Figure 2g, to achieve better impedance matching, the width of the metal patch 322a increases in a stepped manner as it extends farther from the slow-wave lines R1 and R2, reducing signal reflections from the output slow-wave band 32. Furthermore, the metal patch 322a is bonded to the dielectric support rod 62b to enhance signal attenuation within the metal patch 322a and further strengthen the secure connection of the output slow-wave band 32 in the width direction X. The lossy dielectric substrate 322b can be embedded within the longitudinal sidewall 51b to achieve a secure connection with the waveguide body and reuse space in the width direction X, facilitating miniaturization of the traveling wave tube. Furthermore, the increased contact area between the lossy dielectric substrate 322b and the waveguide body facilitates more efficient heat dissipation and improves the stability of the traveling wave tube's operation. The concentrated attenuator 312 also has a similar configuration to the concentrated attenuator 322. Alternatively, the lossy dielectric substrate 322b can be bonded to the inner surface of the longitudinal sidewall 51b rather than embedded within it. The lossy dielectric substrate 322b can also have the aforementioned mating relationship with the inner walls of other sidewalls of the waveguide body. The lossy dielectric substrate 322b prevents the metal patch 322a from directly contacting the waveguide body. Furthermore, it improves the securing effect of the concentrated attenuator 322 and reduces interference with other structures in the slow-wave band. The concentrated attenuator 322 is located within the waveguide body, providing physical protection for the waveguide body.

[0082] Because the input slow-wave band 31 and the output slow-wave band 32 are separated by the truncation gap G, and the concentrated attenuators 312 and 322 are embedded in the inner wall of the waveguide body, the concentrated attenuators 312 and 322 can be designed to be larger, thereby improving attenuation performance and achieving effective isolation between the input slow-wave band 31 and the output slow-wave band 32. Increasing the size of the truncation gap G can also increase the isolation between the slow-wave band 31 and the output slow-wave band 32. Furthermore, the concentrated attenuators 312 and 322 are distributed outside the truncation gap G, achieving spatial multiplexing in the direction of the interaction length between the electron beam 201 and the slow-wave structure 30 (signal transmission direction Y), thereby reducing the length of the slow-wave structure 30 in this direction.

[0083] The size of the truncation gap G in the signal transmission direction Y, that is, the distance D between the input slow-wave band 31 and the output slow-wave band 32, satisfies the following: 2*P2≤D≤5*P1. For example, the value of D is 1.5P1, 1.7P1, 1.9P1, 2P1, 3P1, 4P1, or P1. The value of D may also be 2P2, 2.2P2, 2.5P, 3P2, or 3.5P2. P1 represents the length of a single period of slow-wave units in slow-wave lines T1 and T2 in the input slow-wave band 31, and the length of a single period of slow-wave units in slow-wave lines R1 and R2 in the output slow-wave band 32. When the distance D meets the above conditions, effective isolation between the input slow-wave band 31 and the output slow-wave band 32 is achieved, while also alleviating the problem of the slow-wave structure 30 being oversized due to an excessively large distance D. In addition, the concentrated attenuator 312 and the concentrated attenuator 322 are located outside the truncation gap G. By adjusting the relevant parameters of the two, such as size, material and structure, they can achieve an effect close to that of an ideal attenuator. For example, the loss tangent value of the lossy dielectric substrate 322b is set to be above 0.1, and specifically can be 0.1, 0.2, 0.5, 1, 2, 5, 10 or even infinite, thereby ensuring an effective isolation attenuation effect while not occupying space in the signal transmission direction Y. In theory, the attenuation amount can be infinite while the length of the slow-wave structure 30 is very small, thereby reducing the impact of the introduction of the truncation gap G, the concentrated attenuator 312 and the concentrated attenuator 322 on the gain and electronic efficiency of the traveling wave tube.

[0084] It should be noted that in the above embodiments, the slow-wave structure 30 only exemplarily includes two slow bands, namely an input slow-wave band 31 and an output slow-wave band 32, which are spaced apart along the signal transmission direction Y. However, the present invention is not limited to this embodiment, and multiple intermediate slow bands spaced apart may be inserted between the two. In summary, the slow-wave structure 30 may include N or more slow bands sequentially arranged along the signal transmission direction Y, where N is a positive integer greater than or equal to 2, such as 2, 3, 4, 5, and 6. Each two adjacent slow bands are separated by a truncation gap, with the first slow band in the signal transmission direction Y serving as the input slow band and the last slow band serving as the output slow band. The two ends of each intermediate slow band are connected to a centralized attenuator, and each centralized attenuator is located in an area outside the corresponding truncation gap. For specific configuration of the structure and position of the centralized attenuator corresponding to the intermediate slow band, reference may be made to the centralized attenuators 312 and 322 in the above embodiments.

[0085] By cutting off the signal multiple times in the signal transmission direction Y, the requirements of the output power, gain and electronic efficiency of the traveling wave tube can be further met.

[0086] Furthermore, even when the slow-wave structure is truncated at multiple locations, the dimension D of the truncation gap G between each two slow-wave segments in the signal transmission direction Y still satisfies the following: 2*P2≤D≤5*P1. In this case, P1 represents the length of a single cycle in the slow-wave line of the upstream slow-wave segment, and P2 represents the length of a single cycle in the slow-wave line of the downstream slow-wave segment. If the distance D is too large, the slow-wave structure will be too long. If the distance D is too small, the isolation between adjacent slow-wave segments will be too small.

[0087] The slow-wave segment structure is not limited to n-layer planar slow-wave lines. It can also employ redundant structures such as spiral lines or other structures that slow down electromagnetic wave transmission. Compared to using an entire spiral line without truncation, this approach employs one or more truncation breaks and places the concentrated attenuator outside the truncation gaps, achieving both high gain and high electronic efficiency while also achieving miniaturization. The so-called "redundant structure" refers to a linear structure extending along a non-linear path.

[0088] The effects of the embodiments corresponding to FIG. 2 a to FIG. 2 g are illustrated below by simulation experiments.

[0089] Figure 2h shows the S-parameter simulation diagram of the traveling wave tube corresponding to Figures 2a to 2g, wherein the distance D between the input slow band 31 and the output slow band 32 is selected as 2P1. Referring to Figure 2h, curve ① represents the reflection coefficient S11 parameter of the input slow band 31 and the output slow band 32, and curve ② represents the isolation S21 parameter of the input slow band 31 and the output slow band 32. By observing Figure 2h, it can be seen that the isolation between the input slow band 31 and the output slow band 32 in the traveling wave tube is greater than 48dB.

[0090] Figure 2i shows a schematic diagram of the power flow of the slow-wave structure 30 along the signal propagation direction Y in the high-frequency system shown in Figures 2a to 2g. The horizontal axis represents the distance from the top of the slow-wave structure 30 to the origin of the input slow-wave band 31 along the signal transmission direction Y, in mm. The origin of the input slow-wave band 31 is the end away from the output slow-wave band 32. The vertical axis represents the power flow, in W. By observing Figure 2i, it can be seen that the power flow suddenly drops between 20 mm and 25 mm on the horizontal axis. This section of the slow-wave structure 30 corresponds to the truncation gap G. It can be concluded that through truncation and concentrated attenuation, the power flow of the slow-wave structure 30 along the signal transmission direction Y can be truncation, which is conducive to ensuring the stable operation of the traveling wave tube.

[0091] Figure 2j shows a comparison of the output power of the traveling wave tube corresponding to Figures 2a to 2g and the output power of a conventional traveling wave tube. Curve ③ represents the output power of the traveling wave tube corresponding to Figures 2a to 2g, while curve ④ represents the output power of the conventional traveling wave tube. The conventional traveling wave tube has the same slow-wave structure length, operating voltage, operating current, focusing magnetic field, interaction length, and input power as the traveling wave tube corresponding to Figures 2a to 2g. However, in the conventional traveling wave tube, the support rods are partially replaced by attenuating material and are not truncated. The stabilized output power of curve ③ is 37W, with a gain of 30.7dB; the stabilized output power of curve ④ is 20W, with a gain of 28.1dB. The differences in conversion efficiency and gain between the two can be observed in Figure 2j. Under the same operating parameters and length, the gain of the traveling wave tube corresponding to Figures 2a to 2g is 2.6dB greater than that of the conventional traveling wave tube, and the output power of the former is 17W higher than that of the latter.

[0092] It should be noted that the coordination relationship between the dielectric support rod, the waveguide body and the slow-wave line in the above embodiment is merely exemplary, and the dielectric support rod may also be used to support the slow-wave line in other ways.

[0093] FIG3a illustrates a variation of the structure shown in FIG2b. Referring to FIG3a, the difference from FIG2b lies in that the space enclosed by longitudinal sidewall 51a, two transverse sidewalls (52a and 52b), and two metal ridges (53a and 53b) is completely filled with dielectric material to form dielectric support rods 61a, which have a rectangular cross-section. Similarly, the space between longitudinal sidewall 51b, two transverse sidewalls (52a and 52b), and two metal ridges (53a and 53b) is filled with dielectric material to form dielectric support rods 61b. Slow-wave lines T1 and T2 are embedded in dielectric support rods 61a and 61b at their ends in the width direction X. This supports and secures slow-wave lines T1 and T2, while also increasing the contact area between slow-wave lines T1 and T2 and dielectric support rods 61a and 61b, facilitating sufficient heat dissipation. In addition, the dielectric support rod 61a has a large contact area with the waveguide body, which is conducive to heat dissipation and has a good fixing effect in both the longitudinal direction Z and the width direction X.

[0094] Figure 3b shows a variation of the structure shown in Figure 3a. Referring to Figure 3b, the difference from Figure 3a is that the medium support rod 61a includes a support portion 61a' and a support portion 61a", which are spaced apart along the longitudinal direction Z, both of which are L-shaped. The support portion 61a' is connected to the lateral side wall 52a, and the horizontal portion and the vertical portion of the L-shaped structure are respectively in contact with and connected to the metal ridge 53a, or may be connected only to the lateral side wall 52a; the support portion 61a" is connected to the lateral side wall 52b in a similar manner and cooperates with the metal ridge 53b. Both the support portion 61a' and the support portion 61a" maintain a certain gap with the longitudinal side wall 51a in the width direction X, which is beneficial to improving the output power, but both can also extend along the width direction X to contact the longitudinal side wall 51a to increase the heat dissipation area and improve the fixing effect. Similarly, the dielectric support rod 61b includes a support portion 61b' and a support portion 61b" arranged at intervals along the longitudinal direction Z, and the support portion 61b' and the support portion 61b" are respectively mirrored one-to-one with the support portion 61a' and the support portion 61a". The two side edges of the slow-wave line T1 in the width direction X are respectively embedded one-to-one in the support portion 61a' and the support portion 61b', and the two side edges of the slow-wave line T2 are respectively embedded one-to-one in the support portion 61a" and the support portion 61b". The gaps between support portion 61a' and support portion 61b', as well as the gaps between support portion 61a" and support portion 61b", help widen the transmission space of electron beam 201 in the horizontal direction X, reducing the risk of electron beam 201 directly impacting the dielectric support rods (61a and 61b) on both sides. This widening of electron beam 201 helps increase the output power of the traveling wave tube. The reduced cross-sectional area of ​​the dielectric support rods (61a and 61b) on both sides helps increase the phase velocity of the electromagnetic waves in the slow-wave line.

[0095] Figure 3c shows another variation of the structure shown in Figure 3a. Referring to Figure 3c, the difference from Figure 3a is that the dielectric support rod 61a is clamped between the metal ridge 53a and the metal ridge 53b in the longitudinal direction Z to facilitate clamping and fixing in the longitudinal direction Z, increase the contact area, improve the heat dissipation effect, and is connected to the longitudinal side wall 51a. It can also be embedded in the longitudinal side wall 51a to improve the fixing effect in the width direction X and further improve the heat dissipation effect; the dielectric support rod 61b is clamped between the metal ridge 53a and the metal ridge 53b in a similar manner and is connected to the longitudinal side wall 51b.

[0096] In Figures 3a to 3c, the dielectric support rods 61a are connected to the transverse side walls 52a and 52b in the longitudinal direction Z, and the dielectric support rods 61b are also connected in the longitudinal direction Z, which helps to improve the fixing effect in the longitudinal direction Z. The two side edges of each layer of slow-wave lines in the width direction X are connected one-to-one to the dielectric support rods on the corresponding sides, and can be embedded therein.

[0097] Moreover, the feasibility, assembly simplicity, assembly accuracy, and stability (such as instability caused by charge accumulation, instability caused by oscillation, and heat dissipation instability) of the traveling wave tube slow-wave structure of the above-mentioned assembly methods can be well guaranteed regardless of whether machining or micro-electro-mechanical systems (MEMS) technology is used.

[0098] Furthermore, it should be understood that the above description only describes the structure and position of the dielectric support rod 61a and the dielectric support rod 61b. For multiple slow-wave bands, the design of the remaining dielectric support rods can refer to the dielectric support rod 61a and the dielectric support rod 61b.

[0099] Figure 4a shows a schematic structural diagram of another high-frequency system in a traveling wave tube provided in an embodiment of the present application, Figure 4b shows a main view of the high-frequency system shown in Figure 4a, and Figure 4c shows a cross-sectional view of the high-frequency system shown in Figure 4b in the FF direction. In conjunction with Figures 4a to 4c, the matching relationship between the dielectric support rods (61a, 61b, 62a and 62b), the slow-wave lines (R1 and T1) and the waveguide 50 can be observed. For related introductions, please refer to the previous description of the traveling wave tube shown in Figures 2a to 2g. Figure 4d shows a schematic structural diagram of the high-frequency system shown in Figure 4a after removing the waveguide, and Figure 4e shows a local enlarged view of point C in Figure 4d. The difference from the traveling wave tube shown in Figures 2a to 2g is that both the concentrated attenuator 312 and the concentrated attenuator 322 are in the form of coaxial cables, which can be directly prepared using existing coaxial cables and are relatively easy to obtain. In addition, the input coupler M1, the output coupler M2, the concentrated attenuator 312, and the concentrated attenuator 322 are all located on the side of the longitudinal side wall 51b. The concentrated attenuator 312 and the concentrated attenuator 322 both penetrate the longitudinal side wall 51b and partially extend into the space outside the longitudinal side wall 51b, thereby reducing the space occupied by the internal waveguide body. Specifically referring to Figure 4e, taking the concentrated attenuator 322 as an example, the concentrated attenuator 322 includes, from inner to outer layers, an inner core 322d, a lossy dielectric layer 322e, and an outer conductor layer 322c. The inner core 322d and the outer conductor layer 322c are both made of metal materials, such as oxygen-free copper, aluminum, and stainless steel. The concentrated attenuator 322 can use a standard coaxial cable, that is, the lossy dielectric layer 322e can use a conventional filling dielectric or a high-loss dielectric material. Its specific parameters can refer to the introduction of the relevant parameters of the lossy dielectric substrate 322b above.

[0100] It should be noted that the concentrated attenuator 322 in the form of a coaxial cable is only an example. As long as a linear metal structure is used as the lead-out conductor (such as the inner core 322d) and the lead-out conductor is wrapped with a material that meets the signal loss requirements as the loss medium (loss medium layer 322e), a more stable attenuation effect can be obtained.

[0101] Both concentrated attenuators 312 and 322 utilize coaxial cables, which can still provide impedance matching at the cutoff point and absorb electromagnetic waves reflected from the input and output ports. Furthermore, concentrated attenuators 312 and 322 are located outside the cutoff gap G, penetrate the longitudinal sidewall 51b, and extend beyond the waveguide 50, without adding any additional interaction length. Furthermore, because concentrated attenuators 312 and 322 are separated from the beam-wave interaction zone of electron beam 201, they do not affect the gain and electronic efficiency of the traveling wave tube. However, when both concentrated attenuators 312 and 322 utilize coaxial cables, the coaxial cables can also be positioned along the inner or outer wall of the waveguide body.

[0102] FIG5a shows a schematic structural diagram of another traveling wave tube medium and high frequency system provided by an embodiment of the present application, FIG5b shows a cross-sectional view in the EE direction of FIG5a, FIG5c shows a Z-direction view of the structure shown in FIG5b, and FIG5d shows a view of the structure shown in FIG5b along the negative direction of the X-axis. In combination with FIG5a to FIG5d, the difference from the traveling wave tube shown in FIG2a to FIG2g is that the design of each dielectric support rod and metal ridge is eliminated. Taking the slow wave line T2 and the slow wave line R2 as examples, the slow wave line T2 is spaced apart from the lateral side wall 52b through the dielectric substrate 71b, and the slow wave line R2 is spaced apart from the lateral side wall 52b through the dielectric substrate 72b. The concentrated attenuator 322 includes a lossy dielectric substrate 322f and a metal fold line 322g. The metal fold line 322g extends along the surface of the lossy dielectric substrate 322f, and the metal fold line 322g is spaced apart from the outer wall of the lateral side wall 52b through the lossy dielectric substrate 322f. The metal fold line 322g is connected to the slow-wave line R2 via a conductive wire. The conductive wire connecting the metal fold line 322g and the slow-wave line R2 passes through the lossy dielectric substrate 322f, the lateral sidewall 52b, and the lossy dielectric substrate 322f in sequence through the via V2. To maintain the vacuum environment within the waveguide 50, the via V2 can be filled with a sealing material such as sealant or rubber. The materials of the lossy dielectric substrate 322f and the dielectric substrate 72b can refer to the lossy dielectric substrate 322b described above. The metal fold line 322g is arranged opposite the slow-wave line R2 to alleviate overlap with the metal fold line 312g and reduce signal interference. The metal fold line 322g can adopt a structural design similar to that of the slow-wave line R2, such as a planar design including a sine wave or rectangular wave. As long as the waveform structure is periodically extended, stable signal attenuation can be achieved. After the reflected signal from slow-wave line R2 reaches metal fold line 322g, it is attenuated at metal fold line 322g due to its contact with lossy dielectric substrate 322f. This increases the signal transmission distance and the contact area with lossy dielectric substrate 322f. By extending the concentrated attenuator 322 outside of waveguide 50, there is more space for its installation, increasing design freedom and further enhancing the attenuation effect. Furthermore, metal fold line 322g can be separated from the outer walls of the other sidewalls of the waveguide body by the lossy dielectric substrate 322f. Separating metal fold line 322g from the outer wall of the waveguide body by dielectric substrate 72b provides a larger contact area, improving heat dissipation and securing the outer wall, and reducing the risk of direct contact between metal fold line 322g and dielectric substrate 72b.

[0103] However, it should be understood that the metal fold line 322g is not limited to the above-mentioned form, and can also be a metal line with a redundant structure extending in a plane, so that the reflected signal can be attenuated over a shorter distance.

[0104] Furthermore, the metal fold line 322g and the metal patch 322a in the embodiment corresponding to Figure 2a are both planar structures and can be interchanged. Furthermore, planar structures are not limited to these two forms; the term "planar structure" refers to metal structures extending within a single plane. Correspondingly, the lossy dielectric substrate 322f and the lossy dielectric substrate 322b in the embodiment corresponding to Figure 2a are both planar lossy dielectrics. Using these planar structures, which extend along a single plane of the planar lossy dielectric, can achieve space savings and provide sufficient signal attenuation.

[0105] In addition, the slow-wave line R1 belonging to the same output slow-wave band 32 as the slow-wave line R2 can share a centralized attenuator 322 with the slow-wave line R2 through a power combiner, or both can be designed with a centralized attenuator outside the corresponding lateral sidewall in a similar manner.

[0106] Similarly, the concentrated attenuator 312 includes a lossy dielectric substrate 312f and a metal fold line 312g, which is connected to the slow-wave line T2 through a via V1. The attenuation mode of the slow-wave line T1 can refer to the attenuation mode of the slow-wave line R1.

[0107] Furthermore, in this embodiment, the design of the dielectric support rods in FIG. 2 a to FIG. 2 g may also be adopted, but the structural design of the concentrated attenuators 322 and 312 leading out from the waveguide 50 is maintained.

[0108] Alternatively, the concentrated attenuators 312 and 322 may not be led out of the waveguide 50 . Specifically, the concentrated attenuators may be embedded in the corresponding side walls of the waveguide body.

[0109] In the above embodiments, a method of supporting the slow-wave band using dielectric support rods and dielectric substrates is provided, but the present invention is not limited thereto. Both of the above are merely specific forms of dielectric support components. As long as the dielectric support component is supported between each slow-wave band and the waveguide body, that is, each slow-wave band can be supported on the inner wall of the waveguide body using a certain dielectric support component.

[0110] The configuration of the concentrated attenuator is not limited to the specific forms of the aforementioned embodiments; any concentrated attenuation of signals is acceptable. The concentrated attenuator may include a lead conductor and a lossy dielectric. The lead conductor contacts the lossy dielectric and is connected to the corresponding slow-wave band to achieve signal attenuation. The lossy dielectric substrate 322b, lossy dielectric layer 322e, and lossy dielectric substrate 312f described above are merely specific forms of the lossy dielectric, but are not limited to these forms. The metal patch 322a, inner core 322d, and metal fold line 312g described above are merely specific forms of the lead conductor, but are not limited to these forms.

[0111] Based on the same inventive concept, with reference to the drawings mentioned above, the embodiment of the present application also provides a slow-wave structure 30, which includes a waveguide body, a dielectric support assembly, N slow-wave bands arranged in sequence along the signal transmission direction, and a concentrated attenuator corresponding to each slow-wave band. For the structures, parameters, and coordination relationships of the above-mentioned parts, please refer to the relevant descriptions in the traveling wave tube embodiment above. Since the concentrated attenuator 312 and the concentrated attenuator 322 are both located in the area outside the truncation gap G and do not occupy the space in the truncation gap G, while increasing the volume of the concentrated attenuator (such as 312 and 322) in pursuit of the power capacity and attenuation, it is still convenient to achieve the miniaturization of the entire slow-wave structure 30, and while ensuring high gain and high electronic efficiency, the smaller length of the slow-wave structure 30 can be taken into account. For other beneficial effects, please refer to the description of the relevant structures in the traveling wave tube above.

[0112] Based on the same inventive concept, and with reference to the aforementioned drawings, embodiments of the present application further provide a high-frequency system comprising an input coupler M1, an output coupler M2, and the slow-wave structure provided in the aforementioned embodiments. The input coupler M1 is connected to the input port to feed a signal, and the output coupler M2 is connected to the output port to output the amplified signal. As the core transducer structure of a traveling wave tube, due to the use of the slow-wave structure provided in the aforementioned embodiments, this high-frequency system can achieve both high gain and high electronic efficiency while also being miniaturized, thus facilitating the miniaturization of the traveling wave tube.

[0113] Based on the same inventive concept, FIG6 shows a partial structural diagram of a communication device provided in an embodiment of the present application. Referring to FIG6, an embodiment of the present application further provides a communication device. The embodiment of the present application does not limit the specific form of the communication device. The communication device in the embodiment of the present application can be an evolved Node B (eNB), a radio network controller (RNC), a Node B (NB), a base station controller (BSC), a base transceiver station (BTS), a vehicle-mounted device, a home base station (e.g., a home evolved Node B, or home Node B, HNB), a baseband unit (BBU), an access point (AP) in a wireless fidelity (WIFI) system, a wireless relay node, a wireless backhaul node, a transmission and reception point (TRP or transmission point, TP), etc. It can also be a gNB in ​​a 5G, such as NR, system, or a transmission point (TRP or TP), or a device in a future communication system.

[0114] The communication device provided in the embodiment of the present application includes an upstream external circuit 01, a downstream external circuit 02, and the traveling wave tube provided in the previous embodiment. The upstream external circuit 01 is connected to the input coupler M1, and the upstream signal is fed into the traveling wave tube through the input coupler M1. The downstream external circuit 02 is connected to the output coupler M2. The signal amplified by the traveling wave tube enters the downstream external circuit 02 through the output coupler. The downstream external circuit 02 can be a final stage device such as an antenna, or a device such as a waveguide filter and a waveguide power combiner. Since the above-mentioned traveling wave tube can take into account both high gain and high electronic efficiency while taking into account miniaturization, it helps to realize a high-performance miniaturized communication device. For other descriptions of the traveling wave tube, please refer to the previous embodiment.

[0115] The above are only specific embodiments of the present application, but the scope of protection of this 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 waveguide (50), a dielectric support assembly, and N slow wave bands (31 and 32) sequentially arranged along a signal transmission direction (Y), wherein N is a positive integer greater than or equal to 2; Every two adjacent slow-wave bands (31 and 32) are spaced apart by a truncation gap (G), the waveguide (50) surrounds N slow-wave bands (31 and 32), and the dielectric support assembly is supported between the waveguide (50) and the N slow-wave bands (31 and 32); Along the signal transmission direction (Y), the end of the first slow wave band (31 and 32) away from the Nth slow wave band (31 and 32) has an input port, and the end of the Nth slow wave band (31 and 32) away from the first slow wave band has an output port; One end of each slow-wave band (31 and 32) close to the corresponding truncation gap (G) is connected to a centralized attenuator (312 and 322), and each centralized attenuator (312 and 322) is located outside the truncation gap (G).

2. The slow-wave structure according to claim 1, characterized in that Each of the concentrated attenuators (312 and 322) includes a lead conductor and a lossy dielectric, wherein the lead conductor contacts the lossy dielectric and is connected to the corresponding slow-wave band (31 and 32).

3. The slow-wave structure according to claim 2, characterized in that The lossy medium is in a plate shape, and the lead conductor is a planar structure extending along a plane of the lossy medium.

4. The slow-wave structure according to claim 3, characterized in that The lead conductor is a metal patch (322a).

5. The slow-wave structure according to claim 4, characterized in that Along the direction away from the corresponding slow-wave band (31 and 32), the width of each metal patch (322a) increases in a step-like manner.

6. The slow-wave structure according to claim 3, characterized in that The lead conductor is a metal wire with a redundant structure.

7. The slow-wave structure according to claim 6, characterized in that The redundant structure is a periodically extended waveform structure.

8. The slow-wave structure according to claim 3, characterized in that Each of the concentrated attenuators (312 and 322) is located in a space enclosed by the waveguide (50), and the lead conductor is spaced apart from the inner wall of the waveguide (50) through the loss medium.

9. The slow-wave structure according to claim 8, characterized in that The lossy medium is embedded in the inner wall of the waveguide (50).

10. The slow-wave structure according to claim 3, characterized in that Each of the concentrated attenuators (312 and 322) is located outside the waveguide (50), and the lead conductor is spaced apart from the outer wall of the waveguide (50) through the lossy medium.

11. The slow-wave structure according to claim 2, characterized in that The lead conductor is linear, and the lossy dielectric wraps the lead conductor.

12. The slow-wave structure according to claim 11, characterized in that Each of the concentrated attenuators (312 and 322) includes a coaxial cable, which includes an inner core (322d), a lossy dielectric layer (322e), and an outer conductor layer (322c) arranged in sequence from the inside to the outside, wherein the inner core (322d) forms the lead conductor, and the lossy dielectric layer (322e) forms the lossy dielectric.

13. The slow-wave structure according to claim 11, characterized in that Each of the concentrated attenuators (312 and 322) extends in a direction perpendicular to the sidewall of the waveguide (50) and penetrates the waveguide (50).

14. The slow-wave structure according to claim 2, characterized in that The loss tangent of the lossy medium is greater than 0.

1.

15. The slow-wave structure according to any one of claims 1 to 14, characterized in that: Each of the slow-wave segments (31 and 32) includes a plurality of slow-wave lines (T1 and T2, and R1 and R2) spaced apart along a longitudinal direction (Z), and power combiners (311 and 321) corresponding one to one to the concentrated attenuators (312 and 322), wherein the longitudinal direction (Z) is perpendicular to the signal transmission direction (Y); The slow-wave lines (T1 and T2, and R1 and R2) in each layer extend in the same plane, the slow-wave lines (T1 and T2, and R1 and R2) in each two adjacent slow-wave bands (31 and 32) correspond one to one, and the multiple layers of slow-wave lines (T1 and T2, and R1 and R2) are connected to the corresponding concentrated attenuators (312 and 322) through a power combiner (311 and 321).

16. The slow-wave structure according to claim 15, characterized in that The slow wave lines (T1 and T2, as well as R1 and R2) of each layer are periodically extended wave structures; The distance D between each two adjacent slow-wave bands (31 and 32) satisfies: 2*P2≤D≤5*P1; Among them, P1 represents the single cycle length of the slow wave line (T1 and T2, and R1 and R2) in the upstream slow wave band (31 and 32), and P2 represents the single cycle length of the slow wave line (T1 and T2, and R1 and R2) in the downstream slow wave band (31 and 32).

17. The slow-wave structure according to claim 15, characterized in that The dielectric support assembly includes dielectric support rods (61a and 61b) arranged on both sides of each slow-wave band (31 and 32) in a width direction (X), wherein the width direction (X) is perpendicular to the signal transmission direction (Y) and the longitudinal direction (Z); The two sides of each layer of the slow-wave lines (T1 and T2, and R1 and R2) in the width direction (X) are respectively connected to the dielectric support rods (61a and 61b) on the corresponding sides.

18. The slow-wave structure according to claim 17, characterized in that The waveguide (50) includes two longitudinal side walls (51a and 51b) arranged opposite to each other along the width direction (X), and two transverse side walls (52a and 52b) connecting the two longitudinal side walls (51a and 51b); Each of the dielectric support rods (61a and 61b) is connected to the lateral side walls (52a and 52b) on both sides in the longitudinal direction (Z), and the two side edges of each layer of the slow-wave line (T1 and T2, and R1 and R2) in the width direction (X) are respectively embedded in the dielectric support rods (61a and 61b) on the corresponding sides.

19. The slow-wave structure according to claim 18, characterized in that A metal ridge (53a and 53b) is provided in the middle of each of the lateral side walls (52a and 52b); wherein, Each of the medium supporting rods (61a and 61b) fills the space between the two metal ridges (53a and 53b) and the longitudinal side walls (51a and 51b) on one corresponding side; or, Each of the medium support rods (61a and 61b) is sandwiched between the two metal ridges (53a and 53b) and connected to a corresponding longitudinal side wall (51a and 51b); or, Each of the medium support rods (61a and 61b) includes two support portions (61a' and 61a", and 61b' and 61b") spaced apart along the longitudinal direction (Z), and the two support portions (61a' and 61a", and 61b' and 61b") are respectively connected one-to-one to the two lateral side walls (52a and 52b).

20. The slow-wave structure according to claim 18, characterized in that A metal ridge (53a and 53b) is provided in the middle of each of the transverse side walls (52a and 52b); two dielectric support rods (61a and 61b) are respectively embedded in the longitudinal side walls (51a and 51b) on the corresponding sides, and a certain gap is formed between the two end faces of each of the dielectric support rods (61a and 61b) in the longitudinal direction (Z) and the metal ridges (53a and 53b) on the corresponding sides; Each of the slow-wave bands (31 and 32) is located in the longitudinal direction (Z) and the two outermost layers of the slow-wave lines (T1 and T2, and R1 and R2) are flush one-to-one with the two end faces of each of the dielectric support rods (61a and 61b) in the longitudinal direction (Z).

21. The slow-wave structure according to claim 17, wherein: The input port is connected to the multiple layers of slow-wave lines (T1 and T2, and R1 and R2) of the first slow-wave band (31 and 32) through a power divider (313); Along the signal transmission direction (Y), the power divider (313) and the adjacent power combiners (311 and 321) clamp one of the dielectric support rods (61a and 61b) corresponding to the first slow-wave band (31 and 32) between the two, and each of the remaining two adjacent power combiners (311 and 321) clamps one of the corresponding dielectric support rods (61a and 61b) between the two.

22. The slow-wave structure according to claim 17, wherein: Each of the concentrated attenuators (312 and 322) is located on a side of a corresponding dielectric support rod (61a and 61b) away from the corresponding slow-wave band (31 and 32), and cooperates with the slow-wave band (31 and 32) to clamp the dielectric support rod (61a and 61b) therebetween.

23. The slow-wave structure according to claim 22, characterized in that When the lead conductor is spaced apart from the inner wall of the waveguide (50) through the lossy medium, and the lead conductor is the planar structure, the planar structure contacts the dielectric support rods (61a and 61b).

24. The slow-wave structure according to claim 15, characterized in that Each of the slow-wave lines (T1 and T2, and R1 and R2) includes two layers of slow-wave lines (T1 and T2, and R1 and R2), and each layer of the slow-wave line (T1 and T2, and R1 and R2) is spaced apart from the inner wall of the corresponding side of the waveguide (50) by a dielectric substrate (71b and 72b).

25. A high frequency system, characterized in that The invention comprises an input coupler (M1), an output coupler (M2) and the slow-wave structure according to any one of claims 1 to 24, wherein the input coupler (M1) is connected to the input port, and the output coupler (M2) is connected to the output port.

26. A traveling wave tube, characterized in that: include: An electronic transceiver assembly, a focusing assembly (10) and a high frequency system as claimed in claim 25; The electronic transceiver assembly is used to transmit electrons that pass through each of the slow wave bands (31 and 32) along the signal transmission direction (Y), and the focusing assembly (10) is used to bunch the electrons into electron beams (201).

27. A communication device, characterized in that: The traveling wave tube comprises an upstream external circuit (01), a downstream external circuit (02) and the traveling wave tube according to claim 26, wherein the upstream external circuit (01) is connected to the input coupler (M1), and the downstream external circuit (02) is connected to the output coupler (M2).

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