A full electrostatic bunching planar integrable microstrip slow wave structure traveling wave tube

Abstract

This invention discloses a fully electrostatically focused planar integrable microstrip slow-wave traveling wave tube. This invention uses an electric field generated by electrodes produced by microfabrication technology to replace the magnetic focusing commonly used in vacuum devices. Under the action of the electrodes, the electron beam is subjected to attraction or repulsion forces from electrodes of different polarities. Due to the periodic changes in electrode potential, the particles alternately focus and defocus in the x and y directions, but the fluctuations in the z-direction of propagation remain within a certain range. By matching the electrode period with the period of the microstrip slow-wave structure, a periodic electrostatic potential well is formed in the longitudinal direction, thereby achieving stable constraint and dynamic control of the electron beam, completing the fully electrostatic focusing of the electron beam in the traveling wave tube.

Description

Technical Field

[0001] This invention relates to the field of vacuum electronics technology, and more specifically to a microstrip slow-wave traveling wave tube with a fully electrostatically focused planar integrable structure. Background Technology

[0002] Terahertz traveling wave tubes (TWTs), as high-power, wide-bandwidth terahertz radiation sources, have important applications in 6G communications, security imaging, and biometrics. Traditional TWTs typically employ all-metal slow-wave structures (such as folded waveguides and interleaved double grids) and permanent magnet or periodic permanent magnet focusing systems, which suffer from problems such as large size, heavy weight, complex manufacturing and assembly, and difficulty in integration. Especially as frequencies rise to the terahertz band, the electron beam channel size shrinks to the micrometer scale, posing challenges to traditional magnetic focusing systems, including high magnetic field strength requirements, difficulty in ensuring assembly accuracy, and temperature drift / defocusing.

[0003] In recent years, planar microstrip slow-wave structures based on MEMS technology have attracted attention due to their ease of integration and suitability for mass production. However, existing planar traveling-wave tubes still mostly employ external magnetic focusing, failing to achieve true full integration. More critically, the signal potential carried by the microstrip slow-wave line itself directly interferes with the spatial electric field distribution constructed by the electrostatic focusing electrode, especially causing non-uniform distortion of the focusing electric field in the height direction perpendicular to the electron beam channel. This significantly weakens the effective confinement capability of the micrometer-scale electron beam, thus exposing a fundamental technical deficiency in achieving a fully electrostatically focused, highly integrated planar traveling-wave tube.

[0004] Therefore, there is an urgent need to develop a novel traveling wave tube structure that is fully electrostatically focused, planar, and integrable, in order to promote the development of terahertz vacuum devices toward miniaturization, high performance, and low cost. Summary of the Invention

[0005] Based on the problems mentioned above, the purpose of this invention is to provide a microstrip slow-wave traveling wave tube with an all-electrostatic focusing planar integrable structure. This solves the problem that the signal potential carried by the microstrip slow-wave line itself directly interferes with the spatial electric field distribution constructed by the electrostatic focusing electrode, especially causing non-uniform distortion of the focusing electric field in the height direction perpendicular to the electron beam channel, which significantly weakens the effective constraint capability of the micron-scale electron beam.

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

[0007] This invention provides a fully electrostatically focused planar integrable microstrip slow-wave traveling-wave tube, comprising:

[0008] Dielectric substrate;

[0009] An on-chip electron emission source, integrated at the front end of the dielectric substrate, is used to generate an electron beam;

[0010] A microstrip slow-wave structure, integrated on the dielectric substrate, is used to propagate electromagnetic wave signals and to perform beam injection interaction with the electron beam; wherein, the microstrip slow-wave structure is subjected to a DC negative bias voltage for assisting in focusing the electron beam in the height direction;

[0011] Planar periodic electrostatic focusing electrodes, integrated on the dielectric substrate and located on both sides of the microstrip slow-wave structure, are used to electrostatically focus the electron beam.

[0012] In the above technical solution, the dielectric substrate is the common base of the microstrip slow-wave structure traveling wave tube. As the foundation of the microstrip slow-wave structure traveling wave tube, it realizes the transformation of traveling wave tube from three-dimensional assembly to planar integration.

[0013] The on-chip electron emission source integrated on the front end of the dielectric substrate adopts an on-chip integration approach, which is different from the independent electron gun in the traditional traveling wave tube, and realizes the miniaturization and integrated emission of the electron beam.

[0014] The microstrip slow-wave structure and planar periodic electrostatic focusing electrodes are the core improvements of the microstrip slow-wave traveling-wave tube. Since the signal potential carried by the microstrip slow-wave line itself directly interferes with the spatial electric field distribution constructed by the electrostatic focusing electrodes, especially in the height direction perpendicular to the electron beam channel, it causes non-uniform distortion of the focusing electric field, significantly weakening the effective confinement capability of the micrometer-scale electron beam. Therefore, in the microstrip slow-wave traveling-wave tube of this application, a DC negative bias voltage is applied to the microstrip slow-wave structure, superimposing a DC negative potential while transmitting high-frequency signals. This negative potential forms an inward repulsive force in the height direction of the electron beam, playing a role in assisting in focusing the electron beam and preventing electrons from diverging in the height direction. The planar periodic electrostatic focusing electrodes are located on both sides of the microstrip slow-wave structure to constrain the electron beam laterally, preventing lateral diffusion.

[0015] In one optional embodiment, the microstrip slow-wave structure includes: a microstrip slow-wave branch, with one microstrip slow-wave branch corresponding to one electron beam;

[0016] The microstrip slow-wave branch includes: a slow-wave microstrip line and a microstrip zigzag transition structure;

[0017] The microstrip zigzag transition structure is located at both ends of the slow-wave microstrip line, and the slow-wave microstrip line is interconnected with the input / output probe coupling structure through the microstrip zigzag transition structure.

[0018] In one optional embodiment, the input / output probe coupling structure is fixed to the dielectric substrate by an anchor point; wherein, one end of the input / output probe coupling structure is connected to the microstrip zigzag transition structure, and the other end extends through a gradient section and is suspended in the coupling cavity.

[0019] In one optional embodiment, the planar periodic electrostatic focusing electrode includes: a plurality of quadrupole electrostatic lens arrays periodically arranged along the electron beam propagation direction.

[0020] In one alternative embodiment, each quadrupole electrostatic lens array consists of four sheet electrodes, which are symmetrically distributed around the electron channel axis, and the voltage polarities of adjacent quadrupole electrostatic lens arrays are opposite.

[0021] In one optional embodiment, the sheet electrode is configured with a DC high-voltage feed line, through which the positive potential electrode of the sheet electrode is connected in parallel to a first high-voltage power supply, and the negative potential electrode is connected in parallel to a second high-voltage power supply.

[0022] In one optional embodiment, the DC negative bias voltage is lower than the first high-voltage power supply and the second high-voltage power supply, and forms a composite electrostatic field distribution with the positive potential electrode and the negative potential electrode; wherein, the quadrupole electrostatic lens array provides the main focusing in the lateral direction, and the DC negative bias voltage of the microstrip slow wave structure provides auxiliary constraint in the height direction.

[0023] In one alternative embodiment, the on-chip electron emission source, the microstrip slow-wave structure, and the planar periodic electrostatic focusing electrode are integrated onto the same dielectric substrate using MEMS technology.

[0024] In an alternative embodiment, it further includes a thermal management structure integrated on the back side of the dielectric substrate for dissipating energy generated during high-power motion.

[0025] In one alternative embodiment, the microstrip slow-wave structure is any one of a V-shaped, U-shaped, or conformal microstrip line structure.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] 1. All-electrostatic focusing: No magnets are required, the system size is greatly reduced, and it is suitable for mass production of MEMS;

[0028] 2. No magnetic interference: Multiple traveling wave tubes can be closely arranged, making it suitable for phased array systems;

[0029] 3. Independent optimization: Focusing intensity and beam-wave interaction efficiency can be designed independently;

[0030] 4. All-round constraint: The horizontal direction is mainly focused by planar periodic electrostatic focusing electrodes, and the vertical direction is assisted by negative bias voltage applied on the microstrip slow wave structure, which realizes stable long-distance transmission of electron beam. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0032] Figure 1 This is a schematic diagram of a simple short-period structure of a traveling wave tube according to one embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of the overall structure of one embodiment of the traveling wave tube of the present invention;

[0034] Figure 3 Schematic diagram of microstrip tortuous slow-wave structure and transition structure;

[0035] Figure 4 This is a schematic diagram of the probe-waveguide input-output structure;

[0036] Figure 5 This is a schematic diagram of the lateral layout of the planar periodic electrostatic focusing electrode and the microstrip slow-wave structure.

[0037] Figure 6 A schematic diagram of the longitudinal cross-sectional layout of the planar periodic electrostatic focusing electrode and the microstrip slow-wave structure;

[0038] Figure 7 This is a schematic diagram of a multi-electron-beam parallel structure.

[0039] Figure 8 This is a diagram of a power combining network technology solution.

[0040] Figure 9 This is a flowchart of the manufacturing process for a traveling wave tube.

[0041] The attached diagram shows the markings and corresponding component names:

[0042] 1-Slow-wave microstrip line, 2-Microstrip zigzag transition structure, 3-Input / output probe coupling structure, 4-Positive potential electrode, 5-Negative potential electrode, 6-Dielectric substrate, 7-Input waveguide port, 8-Output waveguide port, 9-On-chip electron emission source. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0044] Example 1

[0045] Embodiment 1 of the present invention provides a fully electrostatically focused planar integrable microstrip slow-wave traveling-wave tube, such as... Figure 1 As shown, a fully electrostatically focused planar integrable microstrip slow-wave traveling-wave tube includes:

[0046] Dielectric substrate;

[0047] An on-chip electron emission source, integrated at the front end of the dielectric substrate, is used to generate an electron beam;

[0048] A microstrip slow-wave structure, integrated on the dielectric substrate, is used to propagate electromagnetic wave signals and to perform beam injection interaction with the electron beam; wherein, the microstrip slow-wave structure is subjected to a DC negative bias voltage for assisting in focusing the electron beam in the height direction;

[0049] Planar periodic electrostatic focusing electrodes, integrated on the dielectric substrate and located on both sides of the microstrip slow-wave structure, are used to electrostatically focus the electron beam.

[0050] It should be noted that traditional methods generally use magnetic focusing (permanent magnets / electromagnets), which uses an axial magnetic field to make electrons spin and confine them near the axis.

[0051] The microstrip slow-wave traveling wave tube of this application uses electric field focusing generated by electrodes through microfabrication technology to replace the magnetic focusing commonly used in vacuum devices today. Under the action of the electrodes, the electron beam will be attracted or repelled by electrodes of different polarities. Due to the periodic change of the electrode potential, the particles will alternately focus and defocus in the x and y directions, but the fluctuation in the z direction of propagation will always be within a certain range. By matching the electrode period with the period of the microstrip slow-wave structure, a periodic electrostatic potential well is formed in the longitudinal direction, thereby achieving stable constraint and dynamic control of the electron beam and completing the full electrostatic focusing of the electron beam in the traveling wave tube.

[0052] Specifically, the dielectric substrate is the common base of the microstrip slow-wave traveling wave tube. As the foundation of the microstrip slow-wave traveling wave tube, it realizes the transformation of traveling wave tube from three-dimensional assembly to planar integration.

[0053] The on-chip electron emission source integrated on the front end of the dielectric substrate adopts an on-chip integration approach, which is different from the independent electron gun in the traditional traveling wave tube, and realizes the miniaturization and integrated emission of the electron beam.

[0054] The microstrip slow-wave structure and planar periodic electrostatic focusing electrodes are the core improvements of the microstrip slow-wave traveling-wave tube. Since the signal potential carried by the microstrip slow-wave line itself directly interferes with the spatial electric field distribution constructed by the electrostatic focusing electrodes, especially in the height direction perpendicular to the electron beam channel, it causes non-uniform distortion of the focusing electric field, significantly weakening the effective confinement capability of the micrometer-scale electron beam. Therefore, in the microstrip slow-wave traveling-wave tube of this application, a DC negative bias voltage is applied to the microstrip slow-wave structure, superimposing a DC negative potential while transmitting high-frequency signals. This negative potential forms an inward repulsive force in the height direction of the electron beam, playing a role in assisting in focusing the electron beam and preventing electrons from diverging in the height direction. The planar periodic electrostatic focusing electrodes are located on both sides of the microstrip slow-wave structure to constrain the electron beam laterally, preventing lateral diffusion.

[0055] In one optional embodiment, the microstrip slow-wave structure includes: a microstrip slow-wave branch, with one microstrip slow-wave branch corresponding to one electron beam;

[0056] The microstrip slow-wave branch includes: a slow-wave microstrip line and a microstrip zigzag transition structure;

[0057] The microstrip zigzag transition structure is located at both ends of the slow-wave microstrip line, and the slow-wave microstrip line is interconnected with the input / output probe coupling structure through the microstrip zigzag transition structure.

[0058] It should be noted that, as Figure 2 As shown, the microstrip slow-wave structure can be any one of the following: zigzag, V-shaped, U-shaped, or conformal microstrip line structure, and its operating frequency covers the millimeter-wave and terahertz bands. It includes microstrip slow-wave branches; in this embodiment, there are at least two microstrip slow-wave branches, each corresponding to an electron beam.

[0059] The microstrip slow-wave branch includes a slow-wave microstrip line and a microstrip zigzag transition structure. The slow-wave microstrip line can be any one of a gold, silver, or copper microstrip line. In this embodiment, a metal U-shaped zigzag periodic microstrip line is used as an example. Figure 3 As shown, the thickness of the metal microstrip line is 1um-100um; the bend width l is 0.1mm-2mm; and the bend period length p is 30um-800um. In this embodiment, the thickness of the gold microstrip line is 5um, the width w is 30um, the bend width l is 0.26mm, and the bend period length p is 115um.

[0060] The microstrip zigzag transition structure is located at both ends of the slow-wave microstrip line, providing a smooth transition from the external standard impedance to the characteristic impedance of the slow-wave line, reducing RF signal reflection. The slow-wave microstrip line is interconnected with the input / output probe coupling structure through the microstrip zigzag transition structure.

[0061] In one optional embodiment, the input / output probe coupling structure is fixed to the dielectric substrate by an anchor point; wherein, one end of the input / output probe coupling structure is connected to the microstrip zigzag transition structure, and the other end extends through a gradient section and is suspended in the coupling cavity.

[0062] It should be noted that the input / output probe coupling structure is a key transition component in the traveling wave tube used to efficiently feed external radio frequency signals into the slow wave structure and extract the amplified signals from the slow wave structure, realizing efficient mode conversion and energy transfer from the external standard waveguide to the internal planar slow wave structure.

[0063] Input / output probe coupling structure as follows Figure 4 As shown, the input / output probe coupling structure and the transition structure at both ends of the planar slow-wave microstrip line adopt an integrated direct interconnection method. The connection is achieved without interruption through continuous metal patterns on the same dielectric substrate, avoiding alignment errors and connection losses caused by mechanical assembly. After connection, it extends through a gradient section with continuously changing geometric dimensions, and finally extends to form a sheet conductor suspended in the coupling cavity. When used as an input probe, it picks up terahertz signals from the external waveguide and feeds them into the slow-wave line. When used as an output probe, it extracts the amplified signal and radiates it to the coupling cavity for output. Thus, it achieves efficient signal coupling between the planar slow-wave circuit and the three-dimensional waveguide interface in a fully integrated, low-loss, and wide-bandwidth manner. The input / output probe coupling structure is fixed by anchor points on the dielectric substrate, and its end is located near the center of the wide side of the rectangular waveguide.

[0064] In one optional embodiment, the planar periodic electrostatic focusing electrode includes: a plurality of quadrupole electrostatic lens arrays periodically arranged along the electron beam propagation direction.

[0065] In one alternative embodiment, each quadrupole electrostatic lens array consists of four sheet electrodes, which are symmetrically distributed around the electron channel axis, and the voltage polarities of adjacent quadrupole electrostatic lens arrays are opposite.

[0066] It should be noted that planar periodic electrostatic focusing electrodes, such as Figure 5 As shown, it includes: multiple sets of quadrupole electrostatic lens arrays arranged periodically along the electron beam propagation direction. Each set of quadrupole electrostatic lens arrays consists of four sheet electrodes. The four sheet electrodes are symmetrically distributed around the electron channel axis. The voltage polarities of adjacent sets of quadrupole electrostatic lens arrays are opposite, thereby generating a strong quadrupole electrostatic field in the cross section (XY plane) of the electron channel.

[0067] Its core improvement lies in the alternating voltage polarity of two adjacent quadrupole lenses along the Z-axis, forming an alternating layout of positive and negative potential electrodes. This creates a series of alternating electrostatic potential traps along the electron beam transmission path, equivalent to a periodic focusing system. This effectively constrains the divergence of the electron beam in the X and Y lateral dimensions, enabling stable long-distance transmission.

[0068] Each quadrupole electrostatic lens array consists of four sheet electrodes, which are symmetrically distributed around the electron channel axis and repeated with a fixed period length Lp. The voltage polarities of adjacent quadrupole electrostatic lens arrays are opposite.

[0069] like Figure 6 As shown, the Nth unit has four electrodes located in the positive X, positive Y, negative X, and negative Y directions. The polarities of the applied DC voltages to these four electrodes are as follows: the X+ electrode is connected to +V (positive potential), the Y+ electrode to -V (negative potential), the X- electrode to +V (positive potential), and the Y- electrode to -V (negative potential). That is, the polarity distribution of the Nth unit is set such that (+V, -V, +V, -V) correspond to the electrodes at positions (X+, Y+, X-, Y-). In the X direction, a repulsive field is formed between the two positive electrodes (X+ and X-), squeezing the electron beam towards the center; in the Y direction, an attractive field is formed between the two negative electrodes (Y+ and Y-), similarly squeezing the electron beam towards the center. Therefore, this unit simultaneously focuses the electron beam in both the X and Y directions.

[0070] Furthermore, the polarity distribution of the N+1th group of units is such that (-V, +V, -V, +V) correspond to the electrodes at positions (X+, Y+, X-, Y-), and so on, alternating periodically.

[0071] By alternating and reversing the polarities of the quadrupole electrodes in adjacent periodic units, each unit forms an inward focusing field in both the X and Y directions. The alternating polarity distribution ensures that the lateral deflection force experienced by the electron beam as it passes through each unit is periodically reversed, thus achieving zero net deflection on a macroscopic scale, preventing the electron beam from deviating from the central axis, and maintaining strong bidirectional focusing of the micrometer-scale electron beam. This periodically alternating electrostatic quadrupole focusing structure, together with the DC negative bias applied by the central microstrip slow wave line, constitutes a fully electrostatic three-dimensional electron beam confinement system that does not require a magnetic field. This fundamentally solves the integration bottlenecks of traditional terahertz traveling wave tube magnetic focusing systems, such as large size, difficult assembly, and temperature drift defocusing.

[0072] In this embodiment, each quadrupole electrode lens unit is composed of four identical high-conductivity oxygen-free copper electrodes. The cross-section of the electrodes is preferably rectangular, and its length direction is parallel to the electron beam transmission direction.

[0073] In one optional embodiment, the sheet electrode is configured with a DC high-voltage feed line, through which the positive potential electrode of the sheet electrode is connected in parallel to a first high-voltage power supply, and the negative potential electrode is connected in parallel to a second high-voltage power supply.

[0074] It should be noted that the quadrupole electrode lens unit is precisely embedded and fixed in the corresponding slot of the dielectric substrate, and buried or microstrip DC high-voltage feed lines are fabricated using thick film printing or thin film deposition processes. These lines are connected to the corresponding electrodes through metallized vias in the insulating plate, with all positive potential electrodes connected in parallel to the first high-voltage power supply V+, and all negative potential electrodes connected in parallel to the second high-voltage power supply V-. The amplitudes of the first and second high-voltage power supplies are precisely adjusted by external circuitry to change the focusing intensity.

[0075] In one optional embodiment, the DC negative bias voltage is lower than the first high-voltage power supply and the second high-voltage power supply, and forms a composite electrostatic field distribution with the positive potential electrode and the negative potential electrode; wherein, the quadrupole electrostatic lens array provides the main focusing in the lateral direction, and the DC negative bias voltage of the microstrip slow wave structure provides auxiliary constraint in the height direction.

[0076] It should be noted that, since the slow-wave microstrip line itself is metallic and has a certain potential, its presence will disturb the spatial electrostatic field generated by the sheet electrode, especially in the height direction (Y direction) of the electron beam, thus weakening the focusing effect. Based on this, this embodiment adopts a synergistic bias design, that is, applying a DC negative bias voltage to the slow-wave microstrip line. Simultaneously, this DC negative bias voltage is lower than the first and second high-voltage power supplies on the sheet electrode, allowing it to not only transmit radio frequency signals but also function as an auxiliary focusing electrode. This DC negative bias voltage, together with the positive and negative potential electrodes, forms a composite electrostatic field distribution. In the lateral direction (X direction), the quadrupole electrode provides primary focusing, while in the height direction (Y direction), the negative potential of the slow-wave line provides auxiliary constraint, thereby achieving omnidirectional stable focusing of the strip electron beam.

[0077] It is important to emphasize that the key to this design lies in the need for coordinated optimization of the DC negative bias voltage amplitude on the slow-wave microstrip line with the voltage of the quadrupole electrostatic lens array to avoid excessive attraction of the electron beam, which could cause electrons to hit the slow-wave microstrip line. This DC negative bias voltage is a DC component, which is superimposed on the RF signal and does not affect the RF transmission characteristics of the microstrip slow-wave structure. After being integrated through MEMS technology, the slow-wave line simultaneously undertakes the dual functions of signal transmission and auxiliary focusing. This design is an improvement based on the solution to the lateral constraint problem of the electron beam in traveling-wave tubes using slow-wave microstrip lines, and further addresses the shortcomings of the interference electric field in slow-wave microstrip lines.

[0078] In one alternative embodiment, the on-chip electron emission source, the microstrip slow-wave structure, and the planar periodic electrostatic focusing electrode are integrated onto the same dielectric substrate using MEMS technology.

[0079] The on-chip electron emission source is formed using semiconductor micro-nano fabrication technology, enabling the initial stages of emission, acceleration, and focusing of multiple electron beams. The on-chip electron emission source is fabricated using one of the following methods: field emission cathode array, thermionic emission thin film, or tunnel junction electron source, and is prepared on a dielectric substrate using semiconductor technology. In this embodiment, a vertical carbon nanotube array formed on the substrate through photolithography and etching processes is used. A voltage is applied to a metal thin film gate with micropores, isolated by an insulating layer of SiO2, above the emitter, generating an electric field at the tip of the emitter to induce electron tunneling emission.

[0080] Thermal management structures, radio frequency attenuation structures, and power combining networks can also be integrated on the dielectric substrate.

[0081] The thermal management structure can be a microchannel heat dissipation layer or a graphene thermal conductive layer integrated on the back of the dielectric substrate to dissipate the heat generated during high-power operation.

[0082] This embodiment can employ a 2-channel, 4-channel, or more parallel electron beam amplification design, which can double the power capacity and improve system reliability, such as... Figure 7 As shown, the slow-wave interaction region includes N (N≥2) microstrip slow-wave branches arranged in parallel in the transverse direction; each microstrip slow-wave branch can adopt a planar ring microstrip line, a curved microstrip line or other periodic slow-wave structure, and its geometric parameters (period, linewidth, gap) are optimized to ensure that the N branches have highly consistent dispersion characteristics and coupling impedance.

[0083] Correspondingly, N independent strip-shaped electron beams are generated by on-chip multi-beam electron emission sources and injected into each microstrip slow-wave branch respectively; the amplified radio frequency signals of each slow-wave branch are combined into a high-power output through an on-chip integrated power combining network.

[0084] The electron gun uses an arrayed on-chip electron emission source, that is, N independent emission units are integrated on a single chip; each emission unit can use the aforementioned field emission array cathode or thin film thermal emission cathode, and is patterned into strip or dot matrix emission regions corresponding one-to-one with the slow wave branch through photolithography.

[0085] After the RF input signal is input through the RF input / output coupling structure, it first enters an on-chip integrated N-channel power distribution network, such as... Figure 8 As shown, the distribution network can be in the form of a Wilkinson power divider or a branch line coupler, which distributes the input signal to the input terminals of N slow wave branches in an equal and in-phase manner.

[0086] Example 2

[0087] This embodiment 2 provides a fabrication process for the fully electrostatically focused planar integrable microstrip slow-wave traveling wave tube provided in embodiment 1, such as... Figure 9 As shown, its preparation method includes:

[0088] 1. Deposit a metal layer (such as Au / Cu) on a dielectric substrate;

[0089] 2. Photolithography forms microstrip lines and electrode patterns;

[0090] 3. Etching forms a three-dimensional structure;

[0091] 4. Fabrication of the electron emission source layer;

[0092] 5. Multi-layer cabling enables electrical interconnection;

[0093] 6. Bond the top cover to form a vacuum seal;

[0094] 7. Exhaust gas, activate cathode, and perform performance testing.

[0095] The microstrip slow-wave traveling wave tube proposed in this invention operates in the millimeter-wave and terahertz frequency bands, and has the advantages of small size, high integration, and suitability for mass production. It is applicable to portable terahertz systems and high-density phased array applications.

[0096] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fully electrostatically focused planar integrable microstrip slow-wave traveling-wave tube, characterized in that, include: Dielectric substrate; An on-chip electron emission source, integrated at the front end of the dielectric substrate, is used to generate an electron beam; A microstrip slow-wave structure, integrated on the dielectric substrate, is used to propagate electromagnetic wave signals and to perform beam injection interaction with the electron beam; wherein, the microstrip slow-wave structure is subjected to a DC negative bias voltage for assisting in focusing the electron beam in the height direction; Planar periodic electrostatic focusing electrodes, integrated on the dielectric substrate and located on both sides of the microstrip slow-wave structure, are used to electrostatically focus the electron beam.

2. The fully electrostatically focused planar integrable microstrip slow-wave traveling wave tube according to claim 1, characterized in that, The microstrip slow-wave structure includes: a microstrip slow-wave branch, with one microstrip slow-wave branch corresponding to one electron beam; The microstrip slow-wave branch includes: a slow-wave microstrip line and a microstrip zigzag transition structure; The microstrip zigzag transition structure is located at both ends of the slow-wave microstrip line, and the slow-wave microstrip line is interconnected with the input / output probe coupling structure through the microstrip zigzag transition structure.

3. The fully electrostatically focused planar integrable microstrip slow-wave traveling wave tube according to claim 2, characterized in that, The input / output probe coupling structure is fixed to the dielectric substrate by anchor points; wherein, one end of the input / output probe coupling structure is connected to the microstrip zigzag transition structure, and the other end extends through a gradient section and is suspended in the coupling cavity.

4. The fully electrostatically focused planar integrable microstrip slow-wave traveling wave tube according to claim 1, characterized in that, The planar periodic electrostatic focusing electrode includes: multiple sets of quadrupole electrostatic lens arrays arranged periodically along the electron beam propagation direction.

5. The fully electrostatically focused planar integrable microstrip slow-wave traveling wave tube according to claim 4, characterized in that, Each quadrupole electrostatic lens array consists of four sheet electrodes, which are symmetrically distributed around the electron channel axis. The voltage polarities of adjacent quadrupole electrostatic lens arrays are opposite.

6. The fully electrostatically focused planar integrable microstrip slow-wave traveling wave tube according to claim 5, characterized in that, The sheet electrode is equipped with a DC high-voltage power supply line, through which the positive potential electrode in the sheet electrode is connected in parallel to a first high-voltage power supply, and the negative potential electrode is connected in parallel to a second high-voltage power supply.

7. The fully electrostatically focused planar integrable microstrip slow-wave structure traveling-wave tube according to claim 6, characterized in that, The DC negative bias voltage is lower than the first high-voltage power supply and the second high-voltage power supply, and forms a composite electrostatic field distribution with the positive potential electrode and the negative potential electrode; wherein, in the lateral direction, it is mainly focused by the quadrupole electrostatic lens array, and in the height direction, it is provided with auxiliary constraint by the DC negative bias voltage of the microstrip slow wave structure.

8. The fully electrostatically focused planar integrable microstrip slow-wave traveling wave tube according to claim 1, characterized in that, The on-chip electron emission source, the microstrip slow-wave structure, and the planar periodic electrostatic focusing electrode are integrated on the same dielectric substrate using MEMS technology.

9. The fully electrostatically focused planar integrable microstrip slow-wave traveling wave tube according to claim 1, characterized in that, Also includes: A thermal management structure, integrated on the back of the dielectric substrate, is used to dissipate energy generated during high-power motion.

10. A fully electrostatically focused planar integrable microstrip slow-wave traveling-wave tube according to claim 1, characterized in that, The microstrip slow-wave structure can be any one of a V-shape, U-shape, or conformal microstrip line structure.

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