Method for determining the conductivity and the internal surface roughness of a folded waveguide and device therefor

Abstract

The application discloses a kind of determination method and device of conductivity and internal surface roughness of folded waveguide, it is related to vacuum electron technology field, wherein, the method includes: obtaining the structure parameters of folded waveguide slow wave structure and the conductivity of first material of folded waveguide, obtain the operating frequency of folded waveguide high-frequency component, determine the attenuation relationship value between folded waveguide and rectangular waveguide based on structure parameters, first material conductivity and operating frequency, measure the measured reflection coefficient and measured transmission coefficient of high-frequency component, determine the target attenuation value of slow wave structure in single period folded waveguide based on measured reflection coefficient and measured transmission coefficient, determine the target conductivity of folded waveguide based on structure parameters, operating frequency, attenuation relationship value and target attenuation value, determine the target internal surface roughness of folded waveguide based on target conductivity.The application solves the technical problems that effective conductivity and internal surface roughness of folded waveguide cannot be accurately obtained in the related art.

Description

Technical Field

[0001] The present invention relates to the field of vacuum electronics technology, and in particular to a method and device for determining the conductivity and inner surface roughness of a folded waveguide. Background Art

[0002] Submillimeter wave and terahertz technologies, as developing disciplines, are of great significance to strengthening national defense and developing the national economy. In the civilian sector, submillimeter waves, with their large information capacity and wide available frequency bandwidth, play a vital role in autonomous driving for cars and helicopters, remote sensing and telemetry, laser spectroscopy, radio astronomy, plasma diagnostics, medicine, environmental protection, bioengineering, and energy development. Terahertz technology, on the other hand, holds broad application prospects in imaging, radar, communications, biomedicine, and security inspection. Obtaining high-performance radiation sources is crucial for the development of millimeter wave and terahertz technologies. Traveling wave tubes, with their high output power, wide operating frequency bandwidth, and high efficiency, are ideal radiation sources for the development of these technologies.

[0003] Folded waveguides are all-metal structures. Their excellent heat dissipation and ease of fabrication make them the preferred interaction circuit for traveling wave tubes (TWTs) in the submillimeter and terahertz bands. Their conductivity and surface roughness significantly impact the TWT's output power, saturation gain, and overall efficiency, requiring careful consideration during design. Therefore, accurately and comprehensively determining the conductivity and surface roughness of folded waveguides is essential for the efficient design of submillimeter-wave TWTs. However, once the folded waveguide is fabricated into a component, these critical conductivity and morphological characteristics cannot be directly measured and must be estimated.

[0004] In related technologies, estimates are often based on the Drude-Sommerfeld theory (a theoretical model that describes the behavior of electrons in metals) and the Hammerstad-Bekkadal formula (an electronic engineering formula that predicts the transconductance performance of MOSFETs (metal-oxide-semiconductor field-effect transistors)). However, the Drude-Sommerfeld theory requires three assumptions: electron dynamics, electron scattering, and spatial uniformity of the electric field force. The Hammerstad-Bekkadal formula requires approximating the surface roughness as a one-dimensional case and then obtaining it by fitting the data. The formula for calculating the effective electrical conductivity of a metal is as follows:

[0005]

[0006] Among them, σ ideal is the ideal conductivity of the metal; s represents the skin depth of the metal, which is based on the operating frequency and the ideal conductivity of the metal σ ideal function; K is the surface roughness of the metal, which can generally be obtained through measurement.

[0007] However, regarding the methods for estimating metal conductivity and surface roughness in the aforementioned related technologies, the Drude-Sommerfeld theory, which assumes that the electric field is spatially uniform across all material frequencies, is inaccurate. Furthermore, the Hammerstad-Bekkada formula, which approximates surface roughness as a one-dimensional case, cannot accurately predict the losses due to reflection on real surfaces, as real surfaces are inherently uneven and lack strict periodicity. While the above formula (1) expresses the relationship between effective conductivity and roughness, the roughness of the inner surface cannot be directly measured after the folded waveguide is fabricated into a component, and therefore the true conductivity of the folded waveguide cannot be obtained.

[0008] To address the above-mentioned problems, no effective solutions have been proposed so far. Summary of the Invention

[0009] The embodiments of the present invention provide a method and apparatus for determining the electrical conductivity and inner surface roughness of a folded waveguide, so as to at least solve the technical problem in the related art that the effective electrical conductivity and inner surface roughness of the folded waveguide cannot be accurately obtained.

[0010] According to one aspect of an embodiment of the present invention, a method for determining the conductivity and inner surface roughness of a folded waveguide is provided, wherein the folded waveguide is sealed in a folded waveguide high-frequency component, and the folded waveguide high-frequency component includes at least: a folded waveguide slow-wave structure and an energy coupling structure, comprising: obtaining structural parameters of the folded waveguide slow-wave structure and the conductivity of a first material of the folded waveguide, and obtaining an operating frequency of the folded waveguide high-frequency component; based on the structural parameters, the conductivity of the first material, and the operating frequency, determining an attenuation relationship value between the folded waveguide and a rectangular waveguide, wherein the length of the wide side and the narrow side of the rectangular waveguide are the same. The side lengths are respectively the same as the wide side length and the narrow side length of the folded waveguide, and the waveguide length of the rectangular waveguide is equal to the straightened length of the folded waveguide for a preset number of periods; the measured reflection coefficient and the measured transmission coefficient of the folded waveguide high-frequency component are measured, and based on the measured reflection coefficient and the measured transmission coefficient, the target attenuation value of the folded waveguide in a single period of the folded waveguide slow-wave structure is determined; based on the structural parameters, the operating frequency, the attenuation relationship value and the target attenuation value, the target conductivity of the folded waveguide is determined, and based on the target conductivity, the target inner surface roughness of the folded waveguide is determined.

[0011] Furthermore, the determination method also includes: processing the base plate and cover plate of the folded waveguide, and milling out a zigzag half-channel and a straight half-channel on the processed base plate and cover plate; welding the base plate and cover plate of the folded waveguide, and cutting the outer shape of the folded waveguide into a cylindrical shape to obtain the folded waveguide slow-wave structure, wherein the folded waveguide included in the folded waveguide slow-wave structure has a preset number of periods; based on the folded waveguide slow-wave structure and the energy coupling structure, preparing the folded waveguide high-frequency component, wherein the energy coupling structure includes: an energy transmission window and a transition waveguide.

[0012] Furthermore, before welding the base plate and the cover plate of each folded waveguide, it also includes: measuring the inner surface roughness of the zigzag half-channel and the straight half-channel to obtain measurement values, wherein the measurement values ​​are used to verify the accuracy of the target inner surface roughness.

[0013] Furthermore, the structural parameters include at least one of the following: the wide side length, narrow side length, half-cycle length, and straight waveguide wall length of the folded waveguide. The step of determining the attenuation relationship value between the folded waveguide and the rectangular waveguide includes: determining the cutoff frequency of the rectangular waveguide based on the wide side length and the speed of light in vacuum, and determining the surface resistance of the rectangular waveguide based on the operating frequency, vacuum magnetic permeability, and the conductivity of the second material of the rectangular waveguide; determining the first attenuation value of the rectangular waveguide based on the surface resistance, the cutoff frequency, the wide side length, the narrow side length, the half-cycle length, the straight waveguide wall length, the operating frequency, and the characteristic impedance of the rectangular waveguide; determining the second attenuation value of the folded waveguide high-frequency component, and determining the attenuation relationship value based on the first attenuation value and the second attenuation value.

[0014] Furthermore, the step of determining the second attenuation value of the folded waveguide high-frequency component includes: determining the number of simulation cycles, and performing simulation modeling on the folded waveguide high-frequency component based on the number of simulation cycles, the structural parameters, and the operating frequency to obtain a simulation model; simulating the simulation model to obtain a simulated reflection coefficient and a simulated transmission coefficient of the folded waveguide high-frequency component; and determining the second attenuation value of the folded waveguide high-frequency component based on the number of simulation cycles, the simulated reflection coefficient, and the simulated transmission coefficient.

[0015] Furthermore, the step of determining the target attenuation value of the folded waveguide slow-wave structure within a single cycle includes: simulating the energy coupling structure to obtain the energy reflection coefficient and energy transmission coefficient of the energy coupling structure; and determining the target attenuation value of the folded waveguide based on the preset number of cycles of the folded waveguide slow-wave structure, a preset correction factor, the measured transmission coefficient, the measured reflection coefficient, and the energy transmission coefficient.

[0016] Furthermore, the step of determining the target inner surface roughness of the folded waveguide based on the target conductivity includes: determining the standard conductivity of the folded waveguide high-frequency component; determining the skin depth of the folded waveguide high-frequency component based on the operating frequency and the standard conductivity; and determining the target inner surface roughness based on the standard conductivity, the skin depth, and the target conductivity.

[0017] According to another aspect of an embodiment of the present invention, a device for determining the conductivity and inner surface roughness of a folded waveguide is provided, wherein the folded waveguide is sealed in a folded waveguide high-frequency component, and the folded waveguide high-frequency component includes at least: a folded waveguide slow-wave structure and an energy coupling structure, including: an acquisition unit for acquiring structural parameters of the folded waveguide slow-wave structure and the first material conductivity of the folded waveguide, and acquiring the operating frequency of the folded waveguide high-frequency component; a first determination unit for determining the attenuation relationship value between the folded waveguide and the rectangular waveguide based on the structural parameters, the first material conductivity, and the operating frequency, wherein the wide side length and narrow side length of the rectangular waveguide are the same. The length is respectively the same as the wide side length and the narrow side length of the folded waveguide, and the waveguide length of the rectangular waveguide is equal to the straightened length of the folded waveguide for a preset number of periods; a second determining unit is used to measure the measured reflection coefficient and the measured transmission coefficient of the folded waveguide high-frequency component, and determine the target attenuation value of the folded waveguide slow-wave structure within a single period based on the measured reflection coefficient and the measured transmission coefficient; a third determining unit is used to determine the target conductivity of the folded waveguide based on the structural parameters, the operating frequency, the attenuation relationship value and the target attenuation value, and determine the target inner surface roughness of the folded waveguide based on the target conductivity.

[0018] Furthermore, the determination device also includes: a first processing module, used to process the base plate and cover plate of the folded waveguide, and mill out a zigzag half-channel and a straight half-channel on the processed base plate and cover plate; a first welding module, used to weld the base plate and cover plate of the folded waveguide, and cut the outer shape of the folded waveguide into a cylindrical shape to obtain the folded waveguide slow-wave structure, wherein the folded waveguide included in the folded waveguide slow-wave structure has a preset number of periods; a first preparation module, used to prepare the folded waveguide high-frequency component based on the folded waveguide slow-wave structure and the energy coupling structure, wherein the energy coupling structure includes: an energy transmission window and a transition waveguide.

[0019] Furthermore, the determination device also includes: a first measurement module, used to measure the inner surface roughness of the meandering half-channel and the straight half-channel before welding the base plate and the cover plate of each folded waveguide, and obtain measurement values, wherein the measurement values ​​are used to verify the accuracy of the target inner surface roughness.

[0020] Furthermore, the structural parameters include at least one of the following: the wide side length, narrow side length, half-cycle length, and straight waveguide wall length of the folded waveguide, and the first determination unit includes: a first determination module, used to determine the cutoff frequency of the rectangular waveguide based on the wide side length and the speed of light in vacuum, and determine the surface resistance of the rectangular waveguide based on the operating frequency, vacuum magnetic permeability, and the conductivity of the second material of the rectangular waveguide; a second determination module, used to determine the first attenuation value of the rectangular waveguide based on the surface resistance, the cutoff frequency, the wide side length, the narrow side length, the half-cycle length, the straight waveguide wall length, the operating frequency, and the characteristic impedance of the rectangular waveguide; a third determination module, used to determine the second attenuation value of the folded waveguide high-frequency component, and determine the attenuation relationship value based on the first attenuation value and the second attenuation value.

[0021] Furthermore, the third determination module includes: a first determination submodule, used to determine the number of simulation cycles, and based on the number of simulation cycles, the structural parameters and the operating frequency, simulate and model the folded waveguide high-frequency component to obtain a simulation model; a first simulation submodule, used to simulate the simulation model to obtain a simulated reflection coefficient and a simulated transmission coefficient of the folded waveguide high-frequency component; and a second determination submodule, used to determine the second attenuation value of the folded waveguide high-frequency component based on the number of simulation cycles, the simulated reflection coefficient and the simulated transmission coefficient.

[0022] Furthermore, the second determination unit includes: a first simulation module, used to simulate the energy coupling structure to obtain the energy reflection coefficient and energy transmission coefficient of the energy coupling structure; a fourth determination module, used to determine the target attenuation value of the folded waveguide based on the preset number of periods of the folded waveguide slow-wave structure, a preset correction factor, the measured transmission coefficient, the measured reflection coefficient and the energy transmission coefficient.

[0023] Furthermore, the third determination unit includes: a fifth determination module for determining the standard conductivity of the folded waveguide high-frequency component; a sixth determination module for determining the skin depth of the folded waveguide high-frequency component based on the operating frequency and the standard conductivity; and a seventh determination module for determining the target inner surface roughness based on the standard conductivity, the skin depth and the target conductivity.

[0024] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is further provided, wherein the computer-readable storage medium includes a stored computer program, wherein when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute any of the above-mentioned methods for determining the conductivity and inner surface roughness of the folded waveguide.

[0025] According to another aspect of an embodiment of the present invention, an electronic device is also provided, comprising one or more processors and a memory, wherein the memory is used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement any of the above-mentioned methods for determining the conductivity and inner surface roughness of a folded waveguide.

[0026] In the present invention, the structural parameters of the folded waveguide slow-wave structure and the first material conductivity of the folded waveguide are obtained, and the operating frequency of the folded waveguide high-frequency component is obtained. Based on the structural parameters, the first material conductivity and the operating frequency, the attenuation relationship value between the folded waveguide and the rectangular waveguide is determined, the measured reflection coefficient and the measured transmission coefficient of the folded waveguide high-frequency component are measured, and based on the measured reflection coefficient and the measured transmission coefficient, the target attenuation value of the folded waveguide in a single cycle of the folded waveguide slow-wave structure is determined. Based on the structural parameters, the operating frequency, the attenuation relationship value and the target attenuation value, the target conductivity of the folded waveguide is determined, and based on the target conductivity, the target inner surface roughness of the folded waveguide is determined.

[0027] In the present invention, based on the parameter data of the actual folded waveguide high-frequency component prepared, the folded waveguide high-frequency component can be simulated to determine the attenuation relationship value between the folded waveguide and the rectangular waveguide, and by measuring the measured reflection coefficient and the measured transmission coefficient of the actual folded waveguide high-frequency component, the target attenuation value of the folded waveguide in a single cycle of the folded waveguide slow-wave structure can be determined, so as to calculate the target conductivity of the folded waveguide based on the attenuation relationship value and the target attenuation value, and inversely deduce the target inner surface roughness of the folded waveguide based on the target conductivity, thereby achieving accurate calculation of the effective conductivity of the folded waveguide and accurate acquisition of the inner surface roughness of the folded waveguide, thereby improving the design accuracy of the traveling wave tube and reducing the design time of the traveling wave tube, thereby solving the technical problem in the related art that the effective conductivity and inner surface roughness of the folded waveguide cannot be accurately obtained, and achieving the technical effect of accurately estimating the effective conductivity and inner surface roughness of the folded waveguide. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0029] Figure 1 is a flow chart of an optional method for determining the conductivity and inner surface roughness of a folded waveguide according to an embodiment of the present invention;

[0030] Figure 2 is a schematic diagram of an optional folded waveguide high-frequency component according to an embodiment of the present invention;

[0031] Figure 3 is a schematic diagram of a K1 variation curve when an optional folded waveguide slow-wave structure according to an embodiment of the present invention adopts different conductivity values ​​and geometric structures;

[0032] Figure 4 is a schematic diagram of an energy coupling structure S21 value and attenuation due to loss obtained by an optional simulation according to an embodiment of the present invention;

[0033] Figure 5 is a schematic diagram of measured values ​​of an optional folded waveguide high-frequency component S11 and attenuation caused by reflection according to an embodiment of the present invention;

[0034] Figure 6 is a schematic diagram of measurement values ​​of an optional folded waveguide high-frequency component S21 according to an embodiment of the present invention;

[0035] Figure 7 is a schematic diagram comparing measured values ​​and simulated values ​​of S21 and loss attenuation of an optional single-period folded waveguide according to an embodiment of the present invention;

[0036] Figure 8 1 is a schematic diagram of a curve showing a change in the S11 value of a folded waveguide slow-wave structure when different metal conductivities are selected according to an embodiment of the present invention;

[0037] Figure 9 1 is a schematic diagram of a curve showing a change in the S21 value of a folded waveguide slow-wave structure when different metal conductivities are selected according to an embodiment of the present invention;

[0038] Figure 10 is a schematic diagram of a curve showing a change in effective conductivity of an optional folded waveguide slow-wave structure as a function of S11 according to an embodiment of the present invention;

[0039] Figure 11 is a schematic diagram of a curve showing a change in effective conductivity of an optional folded waveguide slow-wave structure as a function of S21 according to an embodiment of the present invention;

[0040] Figure 12 is a schematic diagram of an optional device for determining the conductivity and inner surface roughness of a folded waveguide according to an embodiment of the present invention;

[0041] Figure 13 This is a hardware structure block diagram of an electronic device (or mobile device) for a method for determining the conductivity and inner surface roughness of a folded waveguide according to an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0043] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0044] This paper proposes a method for evaluating the effective conductivity and inner surface roughness of folded waveguides, specifically for evaluating the conductivity and inner surface roughness of folded waveguide interaction circuits used in submillimeter and terahertz traveling wave tubes (TWTs). This method calculates the effective conductivity using the S-parameters (including the reflection coefficient and transmission coefficient) of the folded waveguide's high-frequency components, and further infers the folded waveguide's inner surface roughness. This method is direct, accurate, and rapid, providing accurate conductivity and inner surface topography information for TWT designs in the submillimeter and terahertz frequency ranges. This effectively shortens the design cycle and improves design accuracy, thus resolving the issue of inability to directly measure the inner surface roughness of folded waveguide high-frequency components, leading to inaccurate effective conductivity measurements.

[0045] In the present invention, the method for evaluating the effective conductivity and inner surface roughness of a folded waveguide mainly includes four steps: determining the attenuation relationship between the folded waveguide and an equal-length rectangular waveguide, obtaining the S parameters of the energy coupling structure, measuring the S parameters of the folded waveguide high-frequency component, and estimating the metal conductivity and surface roughness. The present invention combines microwave network theory and waveguide transmission theory, without introducing any theoretical assumptions or approximations, to obtain more accurate metal effective conductivity results. Furthermore, the present invention uses the estimated effective conductivity to perform reverse deduction, obtaining a surface roughness value that truly reflects the inner wall morphology of the folded waveguide high-frequency component. Furthermore, the present invention integrates the estimation of effective conductivity and surface roughness with the design and manufacturing process of the traveling wave tube, which can save design time and improve design accuracy.

[0046] Unlike the related art methods of estimating and directly measuring based on the Drude-Sommerfeld theory and the Hammerstad-Bekkada formula, the present invention proposes a method for estimating metal conductivity and surface roughness based on the S parameters of folded waveguide high-frequency components. S parameters are also commonly known as scattering parameter matrices and are widely used in microwave circuit analysis. According to microwave network theory, a folded waveguide high-frequency component can be equivalent to a two-port microwave network. S11 represents the power reflection coefficient at the input end when the output end is connected to a matched load, and S21 represents the power transmission coefficient from the input end to the output end when the output end is connected to a matched load. Therefore, the S11 and S21 parameters can be used to analyze the attenuation caused by loss in folded waveguide high-frequency components. At the same time, according to waveguide transmission theory, when transmitting TE10 mode electromagnetic waves in a rectangular waveguide, the attenuation caused by loss can be represented by the effective conductivity of the metal. Through the above analysis, as long as the relationship between the attenuation of the folded waveguide and the rectangular waveguide is found, the metal conductivity can be expressed by the reflection coefficient S11 and the transmission coefficient S21 of the folded waveguide high-frequency component, and then the metal surface roughness can be inferred by the effective conductivity. Based on this, the present invention combines the microwave network theory and the waveguide transmission theory, without introducing any theoretical assumptions and approximations, and the estimated effective conductivity will be more accurate. At the same time, the present invention uses the inverse method to obtain the roughness of the inner surface of the folded waveguide, and the estimated metal surface roughness will be more realistic. Finally, the present invention integrates the estimation of effective conductivity and surface roughness with the design and manufacturing process of the traveling wave tube, which can save design time and improve design accuracy.

[0047] The present invention will be described in detail below with reference to various embodiments.

[0048] Example 1

[0049] According to an embodiment of the present invention, an embodiment of a method for determining the conductivity and inner surface roughness of a folded waveguide is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0050] Figure 1 FIG. 1 is a flow chart of an optional method for determining the conductivity and inner surface roughness of a folded waveguide according to an embodiment of the present invention. Figure 1 As shown, the method includes the following steps:

[0051] Step S101 , obtaining structural parameters of the folded waveguide slow-wave structure and the conductivity of the first material of the folded waveguide, and obtaining the operating frequency of the folded waveguide high-frequency component.

[0052] Step S102: Based on the structural parameters, the electrical conductivity of the first material, and the operating frequency, the attenuation relationship value between the folded waveguide and the rectangular waveguide is determined, wherein the wide side length and the narrow side length of the rectangular waveguide are respectively the same as the wide side length and the narrow side length of the folded waveguide, and the waveguide length of the rectangular waveguide is equal to the straightened length of the folded waveguide of a preset number of periods.

[0053] Step S103 , measuring the measured reflection coefficient and the measured transmission coefficient of the folded waveguide high-frequency component, and determining the target attenuation value of the folded waveguide slow-wave structure within a single period based on the measured reflection coefficient and the measured transmission coefficient.

[0054] Step S104 , determining a target conductivity of the folded waveguide based on the structural parameters, the operating frequency, the attenuation relationship value, and the target attenuation value, and determining a target inner surface roughness of the folded waveguide based on the target conductivity.

[0055] Through the above steps, the structural parameters of the folded waveguide slow-wave structure and the first material conductivity of the folded waveguide can be obtained, and the operating frequency of the folded waveguide high-frequency component can be obtained. Based on the structural parameters, the first material conductivity and the operating frequency, the attenuation relationship value between the folded waveguide and the rectangular waveguide is determined, the measured reflection coefficient and the measured transmission coefficient of the folded waveguide high-frequency component are measured, and based on the measured reflection coefficient and the measured transmission coefficient, the target attenuation value of the folded waveguide in a single cycle of the folded waveguide slow-wave structure is determined. Based on the structural parameters, the operating frequency, the attenuation relationship value and the target attenuation value, the target conductivity of the folded waveguide is determined, and based on the target conductivity, the target inner surface roughness of the folded waveguide is determined. In an embodiment of the present invention, based on the parameter data of the actual folded waveguide high-frequency component prepared, the folded waveguide high-frequency component can be simulated to determine the attenuation relationship value between the folded waveguide and the rectangular waveguide, and by measuring the measured reflection coefficient and the measured transmission coefficient of the actual folded waveguide high-frequency component, the target attenuation value of the folded waveguide in a single cycle of the folded waveguide slow-wave structure can be determined, so as to calculate the target conductivity of the folded waveguide based on the attenuation relationship value and the target attenuation value, and inversely deduce the target inner surface roughness of the folded waveguide based on the target conductivity, thereby achieving accurate calculation of the effective conductivity of the folded waveguide and accurate acquisition of the inner surface roughness of the folded waveguide, thereby improving the design accuracy of the traveling wave tube and reducing the design time of the traveling wave tube, thereby solving the technical problem in the related art that the effective conductivity and inner surface roughness of the folded waveguide cannot be accurately obtained, and achieving the technical effect of accurately estimating the effective conductivity and inner surface roughness of the folded waveguide.

[0056] The embodiment of the present invention is described in detail below in conjunction with the above steps.

[0057] In an embodiment of the present invention, it is necessary to prepare a folded waveguide high-frequency component for a submillimeter wave and terahertz band traveling wave tube, which includes: a folded waveguide slow-wave structure and an energy coupling structure.

[0058] Optionally, the determination method also includes: processing the base plate and cover plate of the folded waveguide, and milling out a tortuous half-channel and a straight half-channel on the processed base plate and cover plate; welding the base plate and cover plate of the folded waveguide, and cutting the outer shape of the folded waveguide into a cylindrical shape to obtain a folded waveguide slow-wave structure, wherein the folded waveguide included in the folded waveguide slow-wave structure has a preset number of periods; based on the folded waveguide slow-wave structure and the energy coupling structure, preparing a folded waveguide high-frequency component, wherein the energy coupling structure includes: an energy transmission window and a transition waveguide.

[0059] In an embodiment of the present invention, the preparation process of the folded waveguide slow-wave structure is as follows: first, the folded waveguide base plate and cover plate are processed, and then a zigzag semi-channel for the electromagnetic wave to travel and a straight semi-channel for the electron beam to travel are milled out on the base plate and cover plate at high speed, and then the base plate and cover plate are laser welded, and finally, the outer shape of the folded waveguide is cut into a cylindrical shape by secondary processing, thereby completing the preparation of the folded waveguide slow-wave structure.

[0060] In some optional embodiments, no attenuator is introduced into the folded waveguide slow-wave structure. Since the attenuator plays a high-gain role, that is, a low-power input will produce a high-power output, it will cause unstable operating frequency and interfere with the transmission of the wave, resulting in inaccurate attenuation values ​​calculated subsequently.

[0061] In the embodiment of the present invention, since the preparation of the folded waveguide high-frequency component requires multiple mechanical cutting and high-temperature welding, the electrical conductivity and surface roughness of the component and the corresponding parts may be different.

[0062] In the embodiment of the present invention, it is necessary to provide an energy coupling structure on the folded waveguide slow-wave structure to construct a folded waveguide high-frequency component.

[0063] In an embodiment of the present invention, the energy coupling structure includes an energy transmission window and a transition waveguide. The transition waveguide is used to extend the wide and narrow sides of the folded waveguide in the folded waveguide slow-wave structure to standard lengths to facilitate connection with external instruments. The energy transmission window is used to seal the folded waveguide high-frequency component to ensure a vacuum seal within the folded waveguide and to transmit waves, i.e., the energy transmission window at one end inputs waves and the other outputs them.

[0064] Figure 2 is a schematic diagram of an optional folded waveguide high-frequency component according to an embodiment of the present invention, such as Figure 2 As shown, the folded waveguide high-frequency component mainly includes: a folded waveguide slow-wave structure and an energy coupling structure, and the energy coupling structure includes: an energy transmission window and a transition waveguide.

[0065] Optionally, before welding the bottom plate and cover plate of each folded waveguide, the method further includes: measuring the inner surface roughness of the zigzag half-channel and the straight half-channel to obtain measurement values, wherein the measurement values ​​are used to verify the accuracy of the target inner surface roughness.

[0066] In an embodiment of the present invention, before laser welding the bottom plate and cover plate of the folded waveguide, the inner surface roughness of the zigzag half-channel and the straight half-channel needs to be measured so as to compare with the subsequently estimated inner surface roughness to verify the accuracy of the estimation.

[0067] Step S101 , obtaining structural parameters of the folded waveguide slow-wave structure and the conductivity of the first material of the folded waveguide, and obtaining the operating frequency of the folded waveguide high-frequency component.

[0068] In the embodiment of the present invention, the folded waveguide is sealed in a folded waveguide high-frequency component, and the inner surface roughness of the folded waveguide cannot be directly measured. Therefore, some parameters of the folded waveguide are obtained to facilitate the subsequent calculation of its inner surface roughness.

[0069] In step S101, the structural parameters of the folded waveguide slow-wave structure can be obtained first. The structural parameters include: the wide side length, narrow side length, half-period length, straight waveguide wall length, electron injection channel radius, etc. of the folded waveguide. The conductivity of the first material of the folded waveguide can also be obtained (for example, oxygen-free copper, whose ideal conductivity is 5.8×10 7 S / m), and obtain the operating frequency of the folded waveguide high-frequency component (for example, 80-90 GHz), so that the relationship between the attenuation caused by electromagnetic loss in the folded waveguide and the rectangular waveguide can be determined based on these data (that is, the attenuation relationship value between the single-period folded waveguide and the equal-length rectangular waveguide).

[0070] Step S102: Based on the structural parameters, the electrical conductivity of the first material, and the operating frequency, the attenuation relationship value between the folded waveguide and the rectangular waveguide is determined, wherein the wide side length and the narrow side length of the rectangular waveguide are respectively the same as the wide side length and the narrow side length of the folded waveguide, and the waveguide length of the rectangular waveguide is equal to the straightened length of the folded waveguide of a preset number of periods.

[0071] In an embodiment of the present invention, the wide side and narrow side of the folded waveguide are respectively the same as the wide side and narrow side of the rectangular waveguide, and the waveguide length of the rectangular waveguide is equal to the straightened length of the folded waveguide over a preset number of periods. The preset number of periods can be selected based on the simulation software used. For example, if HFSS (High Frequency Structure Simulator) software is used for simulation, half a period is selected for the folded waveguide, and the length of the rectangular waveguide is equal to the straightened length of the half-period folded waveguide. If CST (Computer Simulation Technology) software is used for simulation, one period is selected for the folded waveguide, and the length of the rectangular waveguide is equal to the straightened length of the folded waveguide over one period.

[0072] In step S102 , the relationship between the attenuation caused by electromagnetic loss between the folded waveguide and the rectangular waveguide may be determined based on the structural parameters, the electrical conductivity of the first material, and the operating frequency.

[0073] Optionally, the structural parameters include at least one of the following: the wide side length, narrow side length, half-cycle length, and straight waveguide wall length of the folded waveguide. The step of determining the attenuation relationship value between the folded waveguide and the rectangular waveguide includes: determining the cutoff frequency of the rectangular waveguide based on the wide side length and the speed of light in vacuum, and determining the surface resistance of the rectangular waveguide based on the operating frequency, vacuum magnetic permeability, and the electrical conductivity of the second material of the rectangular waveguide; determining the first attenuation value of the rectangular waveguide based on the surface resistance, cutoff frequency, wide side length, narrow side length, half-cycle length, straight waveguide wall length, operating frequency, and characteristic impedance of the rectangular waveguide; determining the second attenuation value of the folded waveguide high-frequency component, and determining the attenuation relationship value based on the first attenuation value and the second attenuation value.

[0074] In the embodiment of the present invention, assuming that a, b, p, and h represent the wide side length, narrow side length, half-period length, and straight waveguide wall length of the folded waveguide, respectively, the attenuation (i.e., the first attenuation value) caused by loss in a rectangular waveguide having a length equal to the straightened length of a single-period folded waveguide can be expressed as (i.e., based on the surface resistance R s , cutoff frequency f c , wide side length a, narrow side length b, half-period length p, straight waveguide wall length h, operating frequency f and characteristic impedance η of the rectangular waveguide, determine the first attenuation value α of the rectangular waveguide recunit ):

[0075]

[0076] Where a and b represent the wide side length and narrow side length of the folded waveguide, respectively. The rectangular waveguide also takes the same wide side and narrow side length. f is the center frequency (i.e., the operating frequency). η and c represent the characteristic impedance and the speed of light in vacuum, respectively. f c =c / 2a represents the cutoff frequency in the rectangular waveguide (i.e., the cutoff frequency of the rectangular waveguide is determined based on the width of the wide side and the speed of light in a vacuum), represents the surface resistance of the rectangular waveguide (i.e., the surface resistance of the rectangular waveguide is determined based on the operating frequency, the magnetic permeability of the vacuum, and the conductivity of the second material of the rectangular waveguide), where σ eff represents the effective conductivity of the rectangular waveguide material, and μ represents the magnetic permeability of vacuum.

[0077] In this embodiment of the present invention, it is also necessary to determine the second attenuation value α of the folded waveguide high-frequency component. FW , to determine the attenuation relationship value K1 according to the first attenuation value and the second attenuation value, that is, the attenuation relationship caused by attenuation in the single-period folded waveguide and the equal-length rectangular waveguide can be expressed as follows:

[0078]

[0079] Optionally, the step of determining the second attenuation value of the folded waveguide high-frequency component includes: determining the number of simulation cycles, and performing simulation modeling on the folded waveguide high-frequency component based on the number of simulation cycles, structural parameters, and operating frequency to obtain a simulation model; simulating the simulation model to obtain a simulated reflection coefficient and a simulated transmission coefficient of the folded waveguide high-frequency component; and determining the second attenuation value of the folded waveguide high-frequency component based on the number of simulation cycles, the simulated reflection coefficient, and the simulated transmission coefficient.

[0080] In an embodiment of the present invention, the second attenuation value of the folded waveguide high-frequency component can be calculated by simulation modeling. The number of simulation cycles selected during the folded waveguide simulation modeling can be first determined. Then, based on the determined number of simulation cycles, the structural parameters of the folded waveguide slow-wave structure, and the operating frequency of the folded waveguide high-frequency component, the folded waveguide high-frequency component can be simulated and modeled to obtain a simulation model. Then, by simulating the simulation model, the simulated reflection coefficient S of the folded waveguide high-frequency component can be obtained. 11 (%) and simulated transmission coefficient S 21 (%), and then calculate the attenuation (i.e., the second attenuation value) α caused by the loss of a single-period folded waveguide in the folded waveguide high-frequency component based on the number of simulation cycles, simulated reflection coefficient, and simulated transmission coefficient. FW :

[0081]

[0082] Among them, N1 represents the number of cycles selected during the folded waveguide simulation modeling, S 11 (%) and S21 (%) respectively represent the reflection coefficient and transmission coefficient of the folded waveguide high-frequency component expressed in percentage form. These two parameters can be obtained by software simulation calculation.

[0083] For example, the simulation operating frequency range can be selected to be 80-90 GHz. The wavelength of the electromagnetic wave in this operating frequency range is about 3 mm, and the skin depth is about 0.2 μm. During the simulation, the number of complete periods of the folded waveguide slow-wave structure can be selected to be 10.

[0084] Figure 3 FIG. 1 is a schematic diagram of a K1 variation curve when an optional folded waveguide slow-wave structure according to an embodiment of the present invention takes different conductivity values ​​and geometric structures, as shown in FIG. Figure 3 As shown in the figure, with Frequency (GHz) as the horizontal axis and K1 as the vertical axis, it shows the folded waveguide slow wave structure with different conductivity values ​​sigma (for example, sigma = 1.5×10 7 S / m, sigma = 2.5 × 10 7 S / m, sigma = 3.5 × 10 7 S / m, sigma = 4.5 × 10 7 The variation curve of K1 when the geometric structure G (for example, G = 8.2 / mm, G = 7.9 / mm, G = 9.7 / mm, G = 6.8 / mm) is changed. Among them, G is the geometric parameter factor of the folded waveguide slow-wave structure, G = a·b / (p·h·r), a, b, p, h, r represent the wide side, narrow side, half period, straight waveguide wall length and electron beam channel radius of the folded waveguide slow-wave structure respectively. Figure 3 It can be seen that when different G values ​​and metal conductivity are taken, the value of K1 is about 15.

[0085] In some optional embodiments, within the selected operating frequency range (ie, 80-90 GHz), the value of K1 may be selected to be 15.

[0086] For example, the geometric parameters of the folded waveguide slow-wave structure obtained in the simulation are shown in Table 1.

[0087] Table 1

[0088]

[0089] In some optional embodiments, key geometric parameters of the folded waveguide slow-wave structure may be set to: a=2.19 mm, b=0.31 mm, p=0.66 mm, h=0.57 mm, r=0.22 mm.

[0090] In some optional embodiments, the reflection coefficient and the transmission coefficient may be expressed in percentage or in decibel, and the conversion relationship between the two is as follows:

[0091] S(dB)=10log 10 |S(%)| or S(%)=10 S(dB) / 10 (5);

[0092] Step S103 , measuring the measured reflection coefficient and the measured transmission coefficient of the folded waveguide high-frequency component, and determining the target attenuation value of the folded waveguide slow-wave structure within a single period based on the measured reflection coefficient and the measured transmission coefficient.

[0093] In step S103, the S parameters (including the reflection coefficient S11 and the transmission coefficient S21) of the folded waveguide high-frequency component can be measured by a vector network analyzer to calculate the target attenuation value caused by the loss of the folded waveguide in a single cycle of the folded waveguide slow-wave structure based on the measured reflection coefficient and the measured transmission coefficient.

[0094] Optionally, the step of determining the target attenuation value of the folded waveguide slow-wave structure within a single cycle includes: simulating the energy coupling structure to obtain the energy reflection coefficient and energy transmission coefficient of the energy coupling structure; and determining the target attenuation value of the folded waveguide based on a preset number of cycles, a preset correction factor, a measured transmission coefficient, a measured reflection coefficient, and an energy transmission coefficient of the folded waveguide slow-wave structure.

[0095] In an embodiment of the present invention, the S parameters of the energy coupling structure (including the reflection coefficient S11 and the transmission coefficient S21) can be simulated and calculated using CST or HFSS software. For simulation of the energy coupling structure, the window material and sealing material of the energy transmission window, as well as the material of the transition waveguide, can be determined first. Then, the conductivity of the energy transmission window and the transition waveguide can be determined based on the materials used to simulate the energy coupling structure. Thus, the energy reflection coefficient and energy transmission coefficient of the energy coupling structure can be obtained through simulation of the energy coupling structure.

[0096] For example, the energy transmission window can be made of sapphire or diamond, and the sealing material of the energy transmission window can be made of metal, such as Kovar. The material of the transition waveguide can also be Kovar. The conductivity of Kovar under ideal conditions is 2.14×10 6 S / m.

[0097] Figure 4 FIG. 1 is a schematic diagram of an energy coupling structure S21 value and attenuation due to loss obtained by an optional simulation according to an embodiment of the present invention, as shown in FIG. Figure 4As shown in the figure, with Frequency (GHz) as the horizontal axis and S21 (dB) and Aecss im (dB) as the vertical axes, the curves of the S21 value of the energy coupling structure obtained by simulation changing with the operating frequency, and the curves of the attenuation caused by loss in the energy coupling structure obtained by simulation (i.e., AECSSIM) changing with the operating frequency are respectively shown.

[0098] from Figure 4 It can be seen that the S21 value expressed in decibels increases (the absolute value decreases) as the operating frequency increases, which means that the proportion of transmitted power gradually increases, and the loss caused by loss is correspondingly decreasing.

[0099] In an optional embodiment, the input and output energy coupling structures adopt the same structure, so the attenuation caused by loss in the input and output energy coupling structures is also the same.

[0100] In the embodiment of the present invention, the preset period number N2, the preset correction factor K2, and the measured transmission coefficient S of the folded waveguide slow-wave structure are 21HFC , measured reflection coefficient S 11HFC and the energy transfer coefficient S 21ECSSIM , calculate the target attenuation value dA of the folded waveguide FWL (dB):

[0101]

[0102] Where N2 represents the number of periods contained in the folded waveguide slow-wave structure, S 21ECSSIM represents the energy transfer coefficient of the energy coupling structure obtained by simulation calculation, K2 is a correction factor, and the value range can be 1.15~1.25; S 21HFC and S 11HFC are the measured transmission coefficient and the measured reflection coefficient of the folded waveguide high-frequency component, S 21ECSSIM 、S 21HFC and S 11HFC All are expressed in percentage form. If expressed in decibels, they can be converted using formula (5).

[0103] Exemplarily, the period number N2 of the folded waveguide slow-wave structure is 74.

[0104] Figure 5 is a schematic diagram of the measured values ​​of an optional folded waveguide high-frequency component S11 and the attenuation caused by reflection according to an embodiment of the present invention, as shown in FIG. Figure 5As shown in the figure, with Frequency (GHz) as the horizontal axis and S11 (dB) and Aref (dB) as the vertical axes, the curves of the measured value of S11 of the folded waveguide high-frequency component changing with the operating frequency and the curves of the attenuation caused by reflection (i.e., Aref) of the folded waveguide high-frequency component changing with the operating frequency are respectively shown.

[0105] from Figure 5 It can be seen that the measured value curve of the high-frequency component S11 is basically consistent with the attenuation curve caused by reflection. The measured S11 value will be used to estimate the effective conductivity of the folded waveguide slow-wave structure.

[0106] Figure 6 FIG. 1 is a schematic diagram of measurement values ​​of an optional folded waveguide high-frequency component S21 according to an embodiment of the present invention, as shown in FIG. Figure 6 The following figure shows the curves of S21-1, S21-2, and S21-FW-HFC as a function of operating frequency, with Frequency (GHz) as the horizontal axis and S21 (dB) as the vertical axis. S21-1 represents the S21 value of the folded waveguide high-frequency component without a conversion cable; S21-2 represents the measured value of the S21 curve of the conversion cable alone; and S21-FW-HFC represents the S21 value of the folded waveguide high-frequency component measured with a conversion cable.

[0107] In this embodiment, when performing S21 measurement, it is necessary to introduce a conversion cable between the frequency doubling module port of the vector network analyzer and the energy input window port of the folded waveguide high-frequency component. S21-FW-HFC represents the S21 value of the folded waveguide high-frequency component measured when the conversion cable is included.

[0108] In this embodiment, the S21 curve of the conversion cable needs to be measured separately and is represented by S21-2;

[0109] In this embodiment, the S21 value of the folded waveguide high-frequency component without the conversion cable is represented by S21-1, and S21-1 is obtained by subtracting S21-FW-HFC from S21-2.

[0110] In this embodiment, the S21 value S21-1 of the folded waveguide high-frequency component excluding the conversion cable is used to estimate the effective conductivity of the folded waveguide slow-wave structure.

[0111] Figure 7 FIG. 1 is a schematic diagram showing a comparison between the measured and simulated values ​​of S21 and loss attenuation of an optional single-period folded waveguide according to an embodiment of the present invention. Figure 7As shown in the figure, with Frequency (GHz) as the horizontal axis and S21 ratio (dB) as the vertical axis, the measured value of S21 of the single-period folded waveguide (i.e., S21-test) changes with the operating frequency, the simulated value of S21 of the single-period folded waveguide (i.e., S21-Sim) changes with the operating frequency, the measured value of the loss attenuation of the single-period folded waveguide (i.e., Atten-test) changes with the operating frequency, and the simulated value of the loss attenuation of the single-period folded waveguide (i.e., Atten-Sim) changes with the operating frequency are respectively shown.

[0112] For example, a folded waveguide slow-wave structure simulation model was established in HFSS. Its key geometric parameters were consistent with those of the actual processed folded waveguide high-frequency component. The material of the folded waveguide was oxygen-free copper, and the effective conductivity was selected as the estimated value of 2.4×10 7 S / m, the number of folded waveguide periods is selected as 10, the S21 value of the single-period folded waveguide obtained by simulation and the attenuation value caused by loss are expressed as S21-s im and Atten-s im, respectively, while the S21 measurement value of the single-period folded waveguide and the attenuation measurement value caused by loss are expressed as S21-test and Atten-test, respectively.

[0113] from Figure 7 It can be seen that the measured S21 value (S21-test) of the single-period folded waveguide is roughly consistent with the simulated S21 value (S21-s im); the measured attenuation value (Atten-test) of the single-period folded waveguide is basically consistent with the simulated attenuation value (Atten-s im). This shows that the metal effective conductivity estimated by this embodiment is highly accurate and can provide a scientific basis for the design of short millimeter-wave traveling wave tubes.

[0114] Figure 8 FIG. 1 is a schematic diagram of a curve showing a change in the S11 value of a folded waveguide slow-wave structure when different metal conductivities are selected according to an embodiment of the present invention. Figure 8 As shown, with Frequency (GHz) as the horizontal axis and S11 (dB) as the vertical axis, the changing curve of the S11 value of the folded waveguide slow-wave structure when different metal conductivities (for example, sigma = 1.5, sigma = 2.5, sigma = 3.5, sigma = 4.5) are displayed.

[0115] Figure 9 FIG. 1 is a schematic diagram of a curve showing a change in the S21 value of a folded waveguide slow-wave structure when different metal conductivities are selected according to an embodiment of the present invention. Figure 9As shown, with Frequency (GHz) as the horizontal axis and S21 (dB) as the vertical axis, the changing curve of the S21 value of the folded waveguide slow-wave structure when different metal conductivities (for example, sigma = 1.5, sigma = 2.5, sigma = 3.5, sigma = 4.5) are displayed.

[0116] from Figure 8 and Figure 9 It can be seen that the metal conductivity has almost no effect on the S11 parameter of the folded waveguide slow-wave structure, while the S21 parameter decreases significantly with the decrease of metal conductivity. This is because the wavelength of electromagnetic waves in the submillimeter wave band is usually around 3mm, which is much larger than the surface roughness of the folded waveguide slow-wave structure (about 0.1μm-0.8μm). Therefore, the surface roughness (reflected by the effective conductivity of the metal) has almost no effect on the reflection coefficient S11. The skin depth of electromagnetic waves in the submillimeter wave band is generally less than 0.3μm, which is comparable to the surface roughness of the folded waveguide slow-wave structure. Therefore, the surface roughness has a significant effect on the S21 parameter of the folded waveguide slow-wave structure. The rougher the surface (corresponding to the smaller the effective conductivity), the greater the loss of electromagnetic waves in the metal, and the S21 parameter will increase accordingly.

[0117] Step S104 , determining a target conductivity of the folded waveguide based on the structural parameters, the operating frequency, the attenuation relationship value, and the target attenuation value, and determining a target inner surface roughness of the folded waveguide based on the target conductivity.

[0118] In the embodiment of the present invention, the effective conductivity of the folded waveguide (ie, the target conductivity σ eff ) can be estimated by the following formula (i.e., based on the structural parameters (a, b, p, h), operating frequency f, attenuation relationship value K1 and target attenuation value dA FWL (dB), determines the target conductivity of the folded waveguide):

[0119]

[0120] Where N represents the number of periods of the folded waveguide in the folded waveguide high-frequency component, μ represents the magnetic permeability of vacuum, η represents the characteristic impedance, and f c Represents the cutoff frequency in a rectangular waveguide.

[0121] Figure 10 FIG. 1 is a schematic diagram of a curve showing a change in effective conductivity of an optional folded waveguide slow-wave structure with S11 according to an embodiment of the present invention. Figure 10 As shown, S11 is the horizontal axis and Sigma (×10 7 S / m) is the vertical axis, showing the variation curve of the effective conductivity (i.e., Sigma) of the folded waveguide slow-wave structure with the S11 value.

[0122] Figure 11 FIG. 1 is a schematic diagram of a curve showing a change in effective conductivity of an optional folded waveguide slow-wave structure with S21 according to an embodiment of the present invention. Figure 11 As shown, S21 (dB) is the horizontal axis and Sigma (×10 7 S / m) is the vertical axis, which shows the change curve of the effective conductivity (i.e., Sigma) of the folded waveguide slow-wave structure with the S21 value.

[0123] Figure 10 and Figure 11 The two curves in are calculated according to formulas (6) and (7). Figure 9 and Figure 10 It can be seen that: as S11 (expressed in percentage) increases, the attenuation caused by reflection increases, and correspondingly the attenuation caused by loss decreases, and the effective conductivity increases accordingly; as S21 (expressed in decibels) increases (the absolute value decreases), the proportion of transmitted power increases, the attenuation caused by loss decreases, and the effective conductivity also increases accordingly.

[0124] In the embodiment of the present invention, the inner surface roughness of the folded waveguide (ie, the target inner surface roughness) can be inversely deduced based on the target conductivity.

[0125] In some optional embodiments, the inversely estimated inner surface roughness can be compared with a pre-measured value to verify the accuracy of the estimated inner surface roughness. In this embodiment, the inner surface roughness of the folded waveguide high-frequency component increases due to multiple mechanical cutting and high-temperature welding processes during its fabrication. Therefore, the inversely estimated inner surface roughness value is greater than the pre-measured value.

[0126] Optionally, the step of determining the target inner surface roughness of the folded waveguide based on the target conductivity includes: determining the standard conductivity of the folded waveguide high-frequency component; determining the skin depth of the folded waveguide high-frequency component based on the operating frequency and the standard conductivity; and determining the target inner surface roughness based on the standard conductivity, the skin depth and the target conductivity.

[0127] In the embodiment of the present invention, the following formula (8) can be obtained by inversely deducing formula (1) to inversely deducing the target inner surface roughness of the folded waveguide according to the target conductivity:

[0128]

[0129] Here, it is necessary to first determine the standard conductivity σ of the folded waveguide high-frequency component ideal, to determine the skin depth s of the folded waveguide high-frequency component according to the operating frequency and the standard conductivity, and then according to the standard conductivity, skin depth and target conductivity σ eff , calculate the target inner surface roughness K.

[0130] For example, comparing the reverse-inferred inner surface roughness of the folded waveguide high-frequency component (0.16 μm) with the roughness of the folded waveguide baseplate measured before laser welding (0.1313 μm), the former is greater than the latter. This is because the high-frequency component undergoes multiple mechanical cutting and high-temperature welding processes during its fabrication, which increases the roughness of the folded waveguide's inner surface. Therefore, the surface roughness value reverse-inferred by this embodiment more accurately reflects the true morphology of the inner surface of the folded waveguide slow-wave structure.

[0131] In the embodiments of the present invention, the problem of directly obtaining the internal surface morphology of folded waveguide interaction circuits used in submillimeter wave and terahertz traveling wave tubes is solved by determining the attenuation relationship between folded waveguides and equal-length rectangular waveguides, obtaining the S parameters of the energy coupling structure, measuring the S parameters of the folded waveguide high-frequency components, and estimating the metal conductivity and surface roughness. This has important guiding significance for the accurate and efficient design of traveling wave tubes in this band.

[0132] The following describes it in detail with reference to another embodiment.

[0133] Example 2

[0134] The device for determining the conductivity and inner surface roughness of a folded waveguide provided in this embodiment includes multiple implementation units, each implementation unit corresponding to each implementation step in the above-mentioned embodiment 1.

[0135] Figure 12 is a schematic diagram of an optional device for determining the conductivity and inner surface roughness of a folded waveguide according to an embodiment of the present invention, such as Figure 12 As shown, the determining device may include: an acquiring unit 120 , a first determining unit 121 , a second determining unit 122 , and a third determining unit 123 .

[0136] The acquisition unit 120 is configured to acquire the structural parameters of the folded waveguide slow-wave structure and the conductivity of the first material of the folded waveguide, and to acquire the operating frequency of the folded waveguide high-frequency component;

[0137] A first determining unit 121 is configured to determine an attenuation relationship value between the folded waveguide and the rectangular waveguide based on the structural parameters, the electrical conductivity of the first material, and the operating frequency, wherein the wide side length and the narrow side length of the rectangular waveguide are respectively the same as the wide side length and the narrow side length of the folded waveguide, and the waveguide length of the rectangular waveguide is equal to the straightened length of the folded waveguide over a preset number of periods;

[0138] a second determining unit 122 for measuring a measured reflection coefficient and a measured transmission coefficient of the folded waveguide high-frequency component, and determining a target attenuation value of the folded waveguide slow-wave structure within a single period based on the measured reflection coefficient and the measured transmission coefficient;

[0139] The third determining unit 123 is configured to determine a target conductivity of the folded waveguide based on the structural parameters, the operating frequency, the attenuation relationship value, and the target attenuation value, and to determine a target inner surface roughness of the folded waveguide based on the target conductivity.

[0140] The above-mentioned determination device can obtain the structural parameters of the folded waveguide slow-wave structure and the first material conductivity of the folded waveguide through the acquisition unit 120, and obtain the operating frequency of the folded waveguide high-frequency component. The first determination unit 121 determines the attenuation relationship value between the folded waveguide and the rectangular waveguide based on the structural parameters, the first material conductivity and the operating frequency. The second determination unit 122 measures the measured reflection coefficient and the measured transmission coefficient of the folded waveguide high-frequency component, and determines the target attenuation value of the folded waveguide of the folded waveguide slow-wave structure within a single cycle based on the measured reflection coefficient and the measured transmission coefficient. The third determination unit 123 determines the target conductivity of the folded waveguide based on the structural parameters, the operating frequency, the attenuation relationship value and the target attenuation value, and determines the target inner surface roughness of the folded waveguide based on the target conductivity. In an embodiment of the present invention, based on the parameter data of the actual folded waveguide high-frequency component prepared, the folded waveguide high-frequency component can be simulated to determine the attenuation relationship value between the folded waveguide and the rectangular waveguide, and by measuring the measured reflection coefficient and the measured transmission coefficient of the actual folded waveguide high-frequency component, the target attenuation value of the folded waveguide in a single cycle of the folded waveguide slow-wave structure can be determined, so as to calculate the target conductivity of the folded waveguide based on the attenuation relationship value and the target attenuation value, and inversely deduce the target inner surface roughness of the folded waveguide based on the target conductivity, thereby achieving accurate calculation of the effective conductivity of the folded waveguide and accurate acquisition of the inner surface roughness of the folded waveguide, thereby improving the design accuracy of the traveling wave tube and reducing the design time of the traveling wave tube, thereby solving the technical problem in the related art that the effective conductivity and inner surface roughness of the folded waveguide cannot be accurately obtained, and achieving the technical effect of accurately estimating the effective conductivity and inner surface roughness of the folded waveguide.

[0141] Optionally, the determination device also includes: a first processing module, used to process the base plate and cover plate of the folded waveguide, and mill out zigzag half-channels and straight half-channels on the processed base plate and cover plate; a first welding module, used to weld the base plate and cover plate of the folded waveguide, and cut the outer shape of the folded waveguide into a cylindrical shape to obtain a folded waveguide slow-wave structure, wherein the folded waveguide included in the folded waveguide slow-wave structure has a preset number of periods; a first preparation module, used to prepare a folded waveguide high-frequency component based on the folded waveguide slow-wave structure and the energy coupling structure, wherein the energy coupling structure includes: an energy transmission window and a transition waveguide.

[0142] Optionally, the determination device also includes: a first measurement module, used to measure the inner surface roughness of the meandering half-channel and the straight half-channel before welding the base plate and cover plate of each folded waveguide, and obtain measurement values, wherein the measurement values ​​are used to verify the accuracy of the target inner surface roughness.

[0143] Optionally, the structural parameters include at least one of the following: the wide side length, narrow side length, half-cycle length, and straight waveguide wall length of the folded waveguide, and the first determination unit includes: a first determination module, used to determine the cutoff frequency of the rectangular waveguide based on the wide side length and the speed of light in vacuum, and determine the surface resistance of the rectangular waveguide based on the operating frequency, vacuum magnetic permeability and the conductivity of the second material of the rectangular waveguide; a second determination module, used to determine the first attenuation value of the rectangular waveguide based on the surface resistance, cutoff frequency, wide side length, narrow side length, half-cycle length, straight waveguide wall length, operating frequency and characteristic impedance of the rectangular waveguide; a third determination module, used to determine the second attenuation value of the folded waveguide high-frequency component, and determine the attenuation relationship value based on the first attenuation value and the second attenuation value.

[0144] Optionally, the third determination module includes: a first determination submodule, used to determine the number of simulation cycles, and simulate modeling the folded waveguide high-frequency component based on the number of simulation cycles, structural parameters and operating frequency to obtain a simulation model; a first simulation submodule, used to simulate the simulation model to obtain the simulated reflection coefficient and simulated transmission coefficient of the folded waveguide high-frequency component; and a second determination submodule, used to determine the second attenuation value of the folded waveguide high-frequency component based on the number of simulation cycles, the simulated reflection coefficient and the simulated transmission coefficient.

[0145] Optionally, the second determination unit includes: a first simulation module, used to simulate the energy coupling structure to obtain the energy reflection coefficient and energy transmission coefficient of the energy coupling structure; a fourth determination module, used to determine the target attenuation value of the folded waveguide based on the preset number of periods, the preset correction factor, the measured transmission coefficient, the measured reflection coefficient and the energy transmission coefficient of the folded waveguide slow wave structure.

[0146] Optionally, the third determination unit includes: a fifth determination module for determining the standard conductivity of the folded waveguide high-frequency component; a sixth determination module for determining the skin depth of the folded waveguide high-frequency component based on the operating frequency and the standard conductivity; and a seventh determination module for determining the target inner surface roughness based on the standard conductivity, the skin depth and the target conductivity.

[0147] The above-mentioned determination device may also include a processor and a memory. The above-mentioned acquisition unit 120, first determination unit 121, second determination unit 122, third determination unit 123, etc. are all stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to realize the corresponding functions.

[0148] The processor includes a core that retrieves corresponding program units from a memory. One or more cores may be provided, and kernel parameters are adjusted to determine a target conductivity of the folded waveguide based on structural parameters, operating frequency, attenuation relationship value, and target attenuation value. Furthermore, based on the target conductivity, a target inner surface roughness of the folded waveguide is determined.

[0149] The above-mentioned memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0150] The present invention also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program having the following method steps: obtaining structural parameters of a folded waveguide slow-wave structure and a first material conductivity of the folded waveguide, and obtaining an operating frequency of a folded waveguide high-frequency component; determining an attenuation relationship value between the folded waveguide and the rectangular waveguide based on the structural parameters, the first material conductivity, and the operating frequency; measuring a measured reflection coefficient and a measured transmission coefficient of the folded waveguide high-frequency component; and determining a target attenuation value of the folded waveguide within a single period of the folded waveguide slow-wave structure based on the measured reflection coefficient and the measured transmission coefficient; determining a target conductivity of the folded waveguide based on the structural parameters, the operating frequency, the attenuation relationship value, and the target attenuation value; and determining a target inner surface roughness of the folded waveguide based on the target conductivity.

[0151] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is further provided, the computer-readable storage medium including a stored computer program, wherein when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute the above-mentioned method for determining the conductivity and inner surface roughness of the folded waveguide.

[0152] According to another aspect of an embodiment of the present invention, an electronic device is also provided, comprising one or more processors and a memory, wherein the memory is used to store one or more programs, wherein when the one or more programs are executed by one or more processors, the one or more processors implement the above-mentioned method for determining the conductivity and inner surface roughness of the folded waveguide.

[0153] Figure 13 FIG. 1 is a hardware structure block diagram of an electronic device (or mobile device) for determining the conductivity and inner surface roughness of a folded waveguide according to an embodiment of the present invention. Figure 13 As shown, the electronic device may include one or more processors (e.g., Figure 13 The processors 1302a, 1302b, ..., 1302n, etc., which may include but are not limited to processing devices such as microprocessors (MCUs) or programmable logic devices (FPGAs), and a memory 1304 for storing data. In addition, the processors 1302a, 1302b, ..., 1302n, etc., may also include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of the I / O interface), a network interface, a keyboard, a power supply, and / or a camera. It will be understood by those skilled in the art that Figure 13 The structure shown is only for illustration and does not limit the structure of the above electronic device. Figure 13 More or fewer components than shown, or with Figure 13 Different configurations shown.

[0154] The serial numbers of the above embodiments of the present invention are for description only and do not represent the advantages or disadvantages of the embodiments.

[0155] The embodiments or examples of the present disclosure are not exhaustive, but are merely illustrations of some embodiments or examples, and are not intended to be specific limitations on the scope of protection of the present disclosure. In the absence of contradiction, each step in a certain embodiment or example can be implemented as an independent example, and the steps can be arbitrarily combined. For example, a solution after removing some steps in a certain embodiment or example can also be implemented as an independent example, and the order of the steps in a certain embodiment or example can be arbitrarily exchanged. In addition, the optional methods or optional examples in a certain embodiment or example can be arbitrarily combined; in addition, the various embodiments or examples can be arbitrarily combined. For example, some or all steps of different embodiments or examples can be arbitrarily combined, and a certain embodiment or example can be arbitrarily combined with the optional methods or optional examples of other embodiments or examples.

[0156] In the above embodiments of the present invention, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0157] In the several embodiments provided by the present invention, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are merely illustrative. For example, the division of the units can be a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, and can be electrical or other forms.

[0158] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0159] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0160] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk, etc. Various media that can store program codes.

[0161] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for determining the conductivity and inner surface roughness of a folded waveguide, characterized in that: The folded waveguide is sealed in a folded waveguide high-frequency component, and the folded waveguide high-frequency component includes at least: a folded waveguide slow-wave structure and an energy coupling structure, including: Acquire structural parameters of the folded waveguide slow-wave structure and the conductivity of the first material of the folded waveguide, and acquire the operating frequency of the folded waveguide high-frequency component; determining an attenuation relationship value between the folded waveguide and the rectangular waveguide based on the structural parameters, the electrical conductivity of the first material, and the operating frequency, wherein a wide side length and a narrow side length of the rectangular waveguide are respectively the same as a wide side length and a narrow side length of the folded waveguide, and a waveguide length of the rectangular waveguide is equal to a straightened length of the folded waveguide over a preset number of periods; measuring a measured reflection coefficient and a measured transmission coefficient of the folded waveguide high-frequency component, and determining a target attenuation value of the folded waveguide slow-wave structure within a single cycle based on the measured reflection coefficient and the measured transmission coefficient; A target conductivity of the folded waveguide is determined based on the structural parameters, the operating frequency, the attenuation relationship value, and the target attenuation value, and a target inner surface roughness of the folded waveguide is determined based on the target conductivity.

2. The determination method according to claim 1, characterized in that The determination method further includes: Processing the bottom plate and the cover plate of the folded waveguide, and milling a zigzag half-channel and a straight half-channel on the processed bottom plate and the cover plate; Welding the bottom plate and the cover plate of the folded waveguide, and cutting the outer shape of the folded waveguide into a cylindrical shape to obtain the folded waveguide slow-wave structure, wherein the folded waveguide included in the folded waveguide slow-wave structure has a preset number of periods; Based on the folded waveguide slow-wave structure and the energy coupling structure, the folded waveguide high-frequency component is prepared, wherein the energy coupling structure includes: an energy transmission window and a transition waveguide.

3. The determination method according to claim 2, characterized in that: Before welding the bottom plate and the cover plate of each folded waveguide, the method further comprises: The inner surface roughness of the zigzag half-channel and the straight half-channel is measured to obtain measurement values, wherein the measurement values ​​are used to verify the accuracy of the target inner surface roughness.

4. The determination method according to claim 1, characterized in that The structural parameters include at least one of the following: a wide side length, a narrow side length, a half-period length, and a straight waveguide wall length of the folded waveguide. The step of determining the attenuation relationship between the folded waveguide and the rectangular waveguide includes: determining a cutoff frequency of the rectangular waveguide based on the wide side length and the speed of light in a vacuum, and determining a surface resistance of the rectangular waveguide based on the operating frequency, the magnetic permeability of a vacuum, and the electrical conductivity of the second material of the rectangular waveguide; Determining a first attenuation value of the rectangular waveguide based on the surface resistance, the cutoff frequency, the wide side length, the narrow side length, the half-period length, the straight waveguide wall length, the operating frequency, and the characteristic impedance of the rectangular waveguide; A second attenuation value of the folded waveguide high-frequency component is determined, and the attenuation relationship value is determined based on the first attenuation value and the second attenuation value.

5. The determination method according to claim 4, characterized in that: The step of determining a second attenuation value of the folded waveguide high-frequency component comprises: Determining a number of simulation cycles, and performing simulation modeling on the folded waveguide high-frequency component based on the number of simulation cycles, the structural parameters, and the operating frequency to obtain a simulation model; simulating the simulation model to obtain a simulated reflection coefficient and a simulated transmission coefficient of the folded waveguide high-frequency component; The second attenuation value of the folded waveguide high-frequency component is determined based on the number of simulation cycles, the simulated reflection coefficient, and the simulated transmission coefficient.

6. The determination method according to claim 1, characterized in that: The step of determining a target attenuation value of the folded waveguide of the folded waveguide slow-wave structure within a single cycle comprises: Simulating the energy coupling structure to obtain an energy reflection coefficient and an energy transmission coefficient of the energy coupling structure; The target attenuation value of the folded waveguide is determined based on the preset number of periods of the folded waveguide slow-wave structure, the preset correction factor, the measured transmission coefficient, the measured reflection coefficient, and the energy transmission coefficient.

7. The determination method according to claim 1, characterized in that: The step of determining a target inner surface roughness of the folded waveguide based on the target conductivity comprises: determining a standard electrical conductivity of the folded waveguide high-frequency component; determining a skin depth of the folded waveguide high-frequency component based on the operating frequency and the standard conductivity; The target inner surface roughness is determined based on the standard conductivity, the skin depth, and the target conductivity.

8. A device for determining the conductivity and inner surface roughness of a folded waveguide, characterized in that: The folded waveguide is sealed in a folded waveguide high-frequency component, and the folded waveguide high-frequency component includes at least: a folded waveguide slow-wave structure and an energy coupling structure, including: an acquiring unit, configured to acquire structural parameters of the folded waveguide slow-wave structure and the electrical conductivity of the first material of the folded waveguide, and to acquire an operating frequency of the folded waveguide high-frequency component; a first determining unit, configured to determine an attenuation relationship value between the folded waveguide and the rectangular waveguide based on the structural parameters, the electrical conductivity of the first material, and the operating frequency, wherein a wide side length and a narrow side length of the rectangular waveguide are respectively the same as a wide side length and a narrow side length of the folded waveguide, and a waveguide length of the rectangular waveguide is equal to a straightened length of the folded waveguide over a preset number of periods; a second determining unit, configured to measure a measured reflection coefficient and a measured transmission coefficient of the folded waveguide high-frequency component, and determine a target attenuation value of the folded waveguide slow-wave structure within a single cycle based on the measured reflection coefficient and the measured transmission coefficient; A third determining unit is configured to determine a target conductivity of the folded waveguide based on the structural parameters, the operating frequency, the attenuation relationship value, and the target attenuation value, and to determine a target inner surface roughness of the folded waveguide based on the target conductivity.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium includes a stored computer program, wherein when the computer program is executed, the device where the computer-readable storage medium is located is controlled to execute the method for determining the conductivity and inner surface roughness of the folded waveguide according to any one of claims 1 to 7.

10. An electronic device, characterized in that: The method comprises one or more processors and a memory, wherein the memory is used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the method for determining the conductivity and inner surface roughness of the folded waveguide as described in any one of claims 1 to 7.

Images