Flat grid zigzag waveguide design method based on high phase, waveguide and application

Abstract

The invention relates to the technical field of terahertz transmission, and discloses a high-phase-based flat grid zigzag waveguide design method, a waveguide and application, and the method comprises the steps: obtaining first dispersion characteristic data of a low-phase flat grid zigzag waveguide in a Brillouin diagram form, the first dispersion characteristic data comprises a first low-phase working dispersion curve and a first high-phase non-working dispersion curve; acquiring a working frequency range of terahertz waves of a set frequency band transmitted by the low-phase flat grid zigzag waveguide, wherein the working frequency range intersects with the first low-phase working dispersion curve; and adjusting the size of the low-phase flat grid zigzag waveguide to obtain a high-phase flat grid zigzag waveguide, so that the working frequency range is intersected with a high-phase working dispersion curve in a Brillouin diagram form of the high-phase flat grid zigzag waveguide. According to the invention, a fundamental mode high-phase region working strategy is adopted, and the high-frequency characteristic advantage of the flat grid zigzag waveguide is fully exerted while the structural size is obviously increased.

Description

Technical Field

[0001] The present invention relates to the technical field of terahertz transmission, and particularly relates to a design method, waveguide and application of a flat-grid zigzag waveguide based on high phase. Background Art

[0002] Terahertz technology shows broad application prospects in the fields of communication, imaging, biomedicine, etc., but the development of its system is still limited by two core challenges: high path loss and low output power. Among them, the research and development of terahertz radiation sources is the key breakthrough point. By improving the energy supply capacity of the source, the overall performance and application adaptability of the system can be significantly enhanced.

[0003] In recent decades, although solid-state power amplifiers based on gallium nitride and gallium phosphide have made excellent progress in terahertz sources, their limited power output capacity is difficult to meet the transmission requirements of terahertz wavelength distance and high modulation. In contrast, the traveling-wave tube amplifier, as a widely used vacuum electronic device, relies on high-energy modulation of particles and extraction of their energy to amplify radio frequency signals. This amplification mechanism makes the traveling-wave tube significantly superior to solid-state power amplifiers in terms of power, bandwidth, and heat dissipation.

[0004] While developing terahertz traveling-wave tubes, slow-wave structures, as the most important component, have also been widely studied. Among various slow-wave structures, the zigzag waveguide has become one of the preferred slow-wave structures for circular electron beam-driven terahertz traveling-wave tubes. Compared with the traditional zigzag waveguide slow-wave structure, the flat-grid zigzag waveguide has the advantages of wide bandwidth, high coupling impedance, and low loss.

[0005] As the operating frequency increases to the terahertz band, the design of slow-wave structures faces two higher requirements. First, due to the wavelength commensurability effect, the structure size is significantly reduced. From the processing perspective, the device needs to be compatible with existing precision manufacturing processes (such as nano-CNC machining, DRIE deep silicon etching, and UV-LIGA technology), and at the same time meet the requirements of high aspect ratio.

[0006] Secondly, the coupling impedance of high-frequency circuits continues to decrease, which requires more periods of interaction circuits to achieve the saturation state of the traveling-wave tube (usually the interaction circuit needs to occupy more than 80% of the longitudinal length of the high-frequency circuit), resulting in an exponential increase in ohmic loss. From the performance perspective, it is particularly urgent to develop a slow-wave structure scheme with lower ohmic loss.

[0007] The high-order mode operation strategy commonly adopted in gyro-traveling wave tubes has become an effective solution due to its requirement for a relatively large cavity structure size, which can not only reduce the manufacturing difficulty but also decrease the transmission loss. However, in terahertz traveling wave tubes, due to the relatively low coupling impedance, the amplification effect of high-order modes is less than satisfactory, and there is currently a lack of effective alternative solutions. Considering the dispersion characteristics and ohmic losses of terahertz traveling wave tubes, the design of planar grating meander waveguides usually selects the low-phase-velocity region of the fundamental mode as the synchronization region (i.e., adopts a low-phase waveguide), but the strong dispersion characteristics in this region will lead to relatively high ohmic losses and a narrow operating bandwidth. Summary of the Invention

[0008] The present invention provides a design method, waveguide, and application of a planar grating meander waveguide based on high phase to solve the above problems.

[0009] The present invention is achieved through the following technical solutions:

[0010] A design method of a planar grating meander waveguide based on high phase includes:

[0011] Obtain the first dispersion characteristic data in the form of a Brillouin diagram of a low-phase planar grating meander waveguide, where the first dispersion characteristic data includes a first low-phase operating dispersion curve and a first high-phase non-operating dispersion curve;

[0012] Obtain the operating frequency range for the terahertz wave transmitted by the low-phase planar grating meander waveguide, and the operating frequency range intersects with the first low-phase operating dispersion curve;

[0013] Adjust the size of the low-phase planar grating meander waveguide to obtain a high-phase planar grating meander waveguide such that the operating frequency range intersects with the high-phase operating dispersion curve in the form of a Brillouin diagram of the high-phase planar grating meander waveguide.

[0014] As an optimization, adjusting the size of the low-phase planar grating meander waveguide includes adjusting one or more of the waveguide wide side a, period length p, waveguide slot width g, total slow-wave height h, planar grating grid width w, planar grating grid height d, and electron beam radius r.

[0015] As an optimization, the specific method for adjusting the size of the low-phase planar grating meander waveguide to obtain a high-phase planar grating meander waveguide is:

[0016] Set the objective function as the coincidence degree of a specific line segment of the high-phase dispersion curve in the form of a Brillouin diagram of the planar grating meander waveguide in the operating region included in the operating frequency range;

[0017] Determine the parameters to be adjusted, and adjust the determined parameters to be adjusted through a parameter optimization algorithm so that the adjusted flat grid meander waveguide satisfies the objective function. The adjusted flat grid meander waveguide is the high-phase flat grid meander waveguide, and the high-phase dispersion curve of the high-phase flat grid meander waveguide is the high-phase operating dispersion curve of the high-phase flat grid meander waveguide.

[0018] As an optimization,

[0019] The specific process of adjusting the determined parameters to be adjusted through the parameter optimization algorithm is as follows:

[0020] Take the determined parameters to be adjusted as the optimization individuals corresponding to the parameter optimization algorithm, and then perform parameter optimization on the optimization individuals through the corresponding parameter optimization algorithm and the set objective function.

[0021] As an optimization, the specific line segment is the area within mπ before and after with the point of the minimum slope of the high-phase operating dispersion curve of the high-phase flat grid meander waveguide as the midpoint, where m is a positive number.

[0022] The present invention also discloses a waveguide obtained by using the foregoing design method of a flat grid meander waveguide based on high phase.

[0023] As an optimization, slots are opened in the flat grid section and / or the bent grid section of the upper row of grids of the waveguide in the vertical direction perpendicular to the horizontal axis of the electron beam channel, and / or slots are opened in the flat grid section and / or the bent grid section of the lower row of grids of the waveguide in the vertical direction perpendicular to the horizontal axis of the electron beam channel, and the entire electron beam channel passes through the grooves opened in the flat grid section.

[0024] As an optimization, slots matching the electron beam channel are opened in the flat grid sections of the upper row of grids and the lower row of grids of the waveguide.

[0025] As an optimization, the waveguide is a staggered ridge-loaded waveguide or a symmetric ridge-loaded waveguide.

[0026] The present invention also discloses an application of a waveguide, using the foregoing waveguide for high-phase operating dispersion combination and / or high-phase operating phase velocity gradual change / jump and / or high-phase operating phase regulation and / or high-phase operating multi-electron beam channel and power synthesis.

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0028] Break through the traditional working mode selection in the low-phase region of the fundamental mode, adopt the working strategy in the high-phase region of the fundamental mode, and while significantly increasing the structural size, give full play to the high-frequency characteristic advantages of the flat grid meander waveguide;

[0029] The structural parameters are significantly optimized. Compared with the working mode in the low phase velocity region, the width-depth ratio of the flat-gate corrugated waveguide in the high phase region is increased, and the structural size is enlarged.

[0030] Excellent high-frequency characteristics: In the working mode of the high phase region, the dispersion curve is flatter (the beam-wave synchronization is improved), and the ohmic loss is significantly reduced. The analysis results of the high-frequency characteristics show that compared with the low-phase flat-gate corrugated waveguide, the dispersion characteristics of the high-phase flat-gate corrugated waveguide are weaker, and the beam-wave synchronization will be better (manifested as a flatter curve in the working frequency range); the ohmic loss of the high-phase flat-gate corrugated waveguide is significantly reduced;

[0031] Superior transmission performance: Compared with the low-phase flat-gate corrugated waveguide, the high-phase flat-gate corrugated waveguide shows significant low-loss characteristics under the same number of periods. Description of the Drawings

[0032] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, form a part of this application, and do not limit the embodiments of the present invention. In the drawings:

[0033] Figure 1 It is a dispersion characteristic diagram in the form of a Brillouin diagram of a low-phase flat-gate corrugated waveguide;

[0034] Figure 2 It is a dispersion characteristic diagram in the form of a Brillouin diagram of a high-phase flat-gate corrugated waveguide;

[0035] Figure 3 It is a vacuum model of the flat-gate corrugated waveguide;

[0036] Figure 4 It is a comparison diagram of the normalized phase velocity of high-phase operation and low-phase operation;

[0037] Figure 5 It is a comparison diagram of the ohmic loss of high-phase operation and low-phase operation;

[0038] Figure 6 It is a transmission characteristic diagram of a low-phase flat-gate corrugated waveguide;

[0039] Figure 7 It is a transmission characteristic diagram of a high-phase flat-gate corrugated waveguide;

[0040] Figure 8 It is a structural schematic diagram of a high-phase flat-gate corrugated waveguide with slots opened in the flat-gate sections of the upper row of gates and the lower row of gates;

[0041] Figure 9 It is a structural schematic diagram of a high-phase flat-gate corrugated waveguide with slots opened in the bent-gate sections of the upper row of gates and the lower row of gates;

[0042] Figure 10Schematic diagram of the structure of a high-phase flat-gate zigzag waveguide with slots in the flat-gate section and curved-gate section of the upper and lower rows of gates;

[0043] Figure 11 Schematic diagram of the structure of a high-phase flat-gate zigzag waveguide with semi-circular through-slots in the flat-gate section;

[0044] Figure 12 For Figure 11 Front view of the middle half of the high-phase flat-gate zigzag waveguide;

[0045] Figure 13 For Figure 11 Front view of the entire high-phase flat-gate zigzag waveguide;

[0046] Figure 14 Schematic diagram of the structure of a symmetric-ridge-loaded high-phase flat-gate zigzag waveguide;

[0047] Figure 15 Schematic diagram of the structure of a staggered-ridge-loaded high-phase flat-gate zigzag waveguide.

[0048] Markings in the drawings and corresponding component names:

[0049] 1 - Lower row of gates, 2 - Upper row of gates, 3 - Electron beam channel. Detailed implementation manners

[0050] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in combination with embodiments and drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and do not limit the present invention.

[0051] Based on the problems mentioned in the background art, the present invention aims to solve the three core problems faced by existing slow-wave structures in the terahertz frequency band: small structure size, strong dispersion characteristics, and high ohmic losses. In view of the deficiencies of the prior art, a low-loss flat-gate zigzag waveguide slow-wave structure based on the operation in the high-phase region is proposed.

[0052] Embodiment 1 of the present invention provides a design method for a flat-gate zigzag waveguide based on high phase, including:

[0053] S1. Obtain first dispersion characteristic data in the form of a Brillouin diagram of a low-phase flat-gate zigzag waveguide, where the first dispersion characteristic data includes a first low-phase working dispersion curve and a first high-phase non-working dispersion curve.

[0054] The working phase range of the low-phase flat-gate zigzag waveguide is (π, 1.5π).

[0055] S2. Obtain the working frequency range of the terahertz wave transmitted by the low-phase flat-gate zigzag waveguide in a set frequency band, where the working frequency range intersects with the first low-phase working dispersion curve.

[0056] Obtain the dispersion characteristic data of an existing low-phase planar grating meander waveguide. Meanwhile, obtain the operating frequency range of terahertz waves in a set frequency band as the operating region.

[0057] In some embodiments, since it is desired that the device operates in a place with low atmospheric loss (atmospheric loss is caused by water molecules), therefore, taking the operating frequency range of 650 GHz to 670 GHz as an example to illustrate the effect of the present invention, that is, the terahertz waves transmitted by the planar grating meander waveguide are in the range of 650 GHz to 670 GHz. However, the present invention is applicable to the entire frequency band range from microwave, millimeter wave to terahertz wave.

[0058] As Figure 1 shown, it can be known that when the frequency band is 650 GHz to 670 GHz, the phase of the corresponding planar grating meander waveguide is less than 1.5π.

[0059] Due to some defects of the low-phase planar grating meander waveguide, therefore, the present invention attempts to use a high-phase planar grating meander waveguide to see if the defects of the low-phase planar grating meander waveguide can be compensated.

[0060] Since the dispersion characteristic of the slow-wave structure has a significant impact on the synchronization condition of the traveling-wave tube, it is crucial to ensure the consistency of the dispersion characteristics when comparing the performance of the high-phase flat-top grating meander waveguide and the low-phase flat-top grating meander waveguide. This consistency lays the foundation for subsequent comparison of the interaction impedance, ohmic loss, and ultimately the amplification performance.

[0061] The dispersion characteristic of the slow-wave structure ( Figure 1 , 2 ) is closely related to the synchronization condition of the beam-wave interaction in the traveling-wave tube. When comparing the performance of the high-phase flat-top grating meander waveguide and the low-phase flat-top grating meander waveguide, it is necessary to ensure the similarity (pink area) of the dispersion characteristics within the same bandwidth (or the same frequency range), which lays the foundation for subsequent comparison of the ohmic loss.

[0062] S3. Adjust the size of the low-phase planar grating meander waveguide to obtain a high-phase planar grating meander waveguide, so that the operating frequency range intersects with the high-phase operating dispersion curve in the form of the Brillouin diagram of the high-phase planar grating meander waveguide.

[0063] Since the operating frequency f is inversely proportional to the electromagnetic wave wavelength Lamuta. That is, when the operating frequency decreases, the wavelength increases, and the corresponding device size will increase. Therefore, when adjusting the size of the low-phase planar grating meander waveguide, the size of the low-phase planar grating meander waveguide will be enlarged.

[0064] In some embodiments, adjusting the dimensions of the low-phase planar-gate meander waveguide includes adjusting one or more of the waveguide wide side a, the period length p, the waveguide slot width g, the total slow-wave height h, the planar-gate width w, the planar-gate height d, and the electron beam radius r.

[0065] In some embodiments, the specific method for adjusting the dimensions of the low-phase planar-gate meander waveguide to obtain a high-phase planar-gate meander waveguide is as follows:

[0066] Set the objective function as the coincidence degree of a specific line segment of the high-phase dispersion curve of the planar-gate meander waveguide in the Brillouin diagram form within the working region included in the working frequency range;

[0067] Determine the parameters to be adjusted, and adjust the determined parameters to be adjusted through a parameter optimization algorithm so that the adjusted planar-gate meander waveguide satisfies the objective function. The adjusted planar-gate meander waveguide is the high-phase planar-gate meander waveguide, and the high-phase dispersion curve of the high-phase planar-gate meander waveguide is the high-phase working dispersion curve of the high-phase planar-gate meander waveguide.

[0068] In some embodiments, the specific process of adjusting the determined parameters to be adjusted through a parameter optimization algorithm is as follows:

[0069] Take the determined parameters to be adjusted as the optimization individuals corresponding to the parameter optimization algorithm, and then perform parameter optimization on the optimization individuals through the corresponding parameter optimization algorithm and the set objective function.

[0070] The parameter optimization algorithm includes all algorithms that are currently known, such as the genetic algorithm, the black-winged kite algorithm, etc.

[0071] Suppose the parameter optimization algorithm is the genetic algorithm. Take the determined parameters to be adjusted as the gene positions of the chromosome, and perform parameter optimization through the genetic algorithm and the set objective function.

[0072] Specifically, the specific process of adjusting the determined parameters to be adjusted through the genetic algorithm is as follows:

[0073] A1. Set the number of iterations of the genetic algorithm and the number of individuals in each generation of the population. Each individual includes the determined parameters to be adjusted;

[0074] A2. Encode the determined parameters to be adjusted to obtain the encoded values of the individuals, and randomly generate an initial population formed by several individuals. Let this initial population be the parental population, and let the individuals in the parental population be parental individuals. The encoded value of each parental individual includes the determined parameters to be adjusted;

[0075] A3. Simulate according to the coding values of each of the parent individuals in the parent population to obtain second dispersion characteristic data in the form of a Brillouin diagram of the planar grid meandering waveguide corresponding to the parent individuals;

[0076] A4. Calculate the fitness function based on the second dispersion characteristic data, and calculate and sort the fitness values of each of the parent individuals in the parent population according to the fitness function;

[0077] A5. Save the first M parent individuals with the largest fitness values in the parent population. Select parent individuals from all parent individuals except the first M parent individuals with the largest fitness values through roulette wheel selection for crossover and mutation operations to obtain offspring individuals. Then calculate the fitness values of the offspring individuals after crossover and mutation and sort them, reinsert the offspring individuals into the parent population according to the fitness values, select a set number of individuals to be solved to form a new parent population, and then return to A3;

[0078] A6. Repeat A3 - A5 until the iteration number is reached or the objective function value is within the specified threshold range. The finally obtained parent population is the set of feasible solutions, and the parent individuals in the parent population are feasible individuals.

[0079] Assume that, in some embodiments, the parameter tuning algorithm is the black-winged kite algorithm. Use the parameters that have been determined to need adjustment as black-winged kite individuals, and perform parameter optimization through the black-winged kite algorithm and the set objective function

[0080] B1. Initialize the algorithm parameters of the black-winged kite algorithm, where the algorithm parameters include the number of the black-winged kite population, the maximum number of iterations, and the optimization range;

[0081] B2. Randomly initialize the black-winged kite population;

[0082] B3. Simulate each black-winged kite individual in the black-winged kite population to obtain third dispersion characteristic data in the form of a Brillouin diagram of the planar grid meandering waveguide, and calculate the fitness value generated at the position of each black-winged kite individual according to the third dispersion characteristic data of the corresponding black-winged kite individual;

[0083] B4. Re-sort the black-winged kite individuals according to the fitness value;

[0084] B5. Perform attack behavior and migration behavior on the re-sorted black-winged kite individuals to update the positions of the black-winged kite individuals;

[0085] B6. Determine whether the maximum number of iterations has been reached. If so, end and output the current black-winged kite population. Otherwise, return to B3.

[0086] The specific formula for randomly initializing the black-winged kite population is:

[0087] X i = BK lb + rand(BK ub - BK lb )

[0088] Among them, X i represents the position of the \(i\)-th black-winged kite individual, where \(i\) is an integer between 1 and pop, and pop is the number of black-winged kite individuals in the black-winged kite population. BK lb and BK ub are the lower and upper bounds of the \(j\)-th dimension of the black-winged kite individual respectively, and rand is a value randomly selected between [0, 1].

[0089] The mathematical model of the attack behavior of the black-winged kite individual is as follows:

[0090]

[0091] Among them, represents the position of the \(i\)-th black-winged kite individual in the \(j\)-th dimension and at the \((t + 1)\)-th iteration step; represents the position of the \(i\)-th black-winged kite individual in the \(j\)-th dimension and at the \(t\)-th iteration step; \(r\) is a random number between 0 and 1, and \(p\) is a constant of 0.9; \(T\) is the maximum number of iterations, and \(t\) is the number of iterations completed so far.

[0092] The mathematical model of the migration behavior of the black-winged kite individual is as follows:

[0093]

[0094] m = 2×sin(r + π / 2)

[0095] Among them, represents the position of the \(i\)-th black-winged kite individual in the \(j\)-th dimension and at the \((t + 1)\)-th iteration step; represents the position of the \(i\)-th black-winged kite individual in the \(j\)-th dimension and at the \(t\)-th iteration step; represents the leading scorer of the \(j\)-th dimension of the black-winged kite individual at the \(t\)-th iteration so far, that is, the optimal black-winged kite individual with the maximum fitness value, F i represents the current position of any black-winged kite individual in the \(j\)-th dimension at the \(t\)-th iteration; F ri represents the fitness value of the random position of any black-winged kite individual in the \(j\)-th dimension at the \(t\)-th iteration; C(0, 1) represents the Cauchy mutation.

[0096] The specific expression of the Cauchy mutation is:

[0097]

[0098] Among them, \(x\) represents a random variable.

[0099] It should be noted that the fitness function in the black-winged kite algorithm and the genetic algorithm is the same as the objective function.

[0100] In some embodiments, the specific line segment is a region within aπ before and after the midpoint, where the midpoint is the point with the minimum slope of the high-phase working dispersion curve of the high-phase flat-gate meander waveguide, and a is a positive number.

[0101] Here, it should be noted that since the phase range corresponding to the high-phase working dispersion curve of the high-phase flat-gate meander waveguide is [1.5π, 2π), and the flattest dispersion curve is taken in this region, this can make the working bandwidth of the high-phase flat-gate meander waveguide larger.

[0102] Through the above design process, the Figure 2 dispersion characteristic diagram of the high-phase flat-gate meander waveguide can be obtained.

[0103] Figure 1 shows the dispersion characteristics of the low-phase flat-gate meander waveguide. The voltage line (green line) intersects the fundamental mode at 1.31π. Figure 2 shows the dispersion characteristics of the high-phase flat-gate meander waveguide. The same voltage line intersects the fundamental mode at 1.85π. The intersection region (highlighted in white) indicates that, compared with the low-phase flat-gate meander waveguide, the overlapping region between the voltage line and the high-phase flat-gate meander waveguide is larger, indicating a wider frequency synchronization region.

[0104] Next, specific numerical parameters will be used for illustration.

[0105] Through the above method, the dimensions in Table 1 can be obtained. It should be noted that in this embodiment, the flat-gate grid height d and the electron beam channel radius r are not adjusted.

[0106] The electron beam channel radius r is controlled to be unchanged, considering that the same set of electron optical systems can be used to compare the performance of different slow-wave structures.

[0107] Table 1 Comparison of the dimensions of the low-phase flat-gate meander waveguide slow-wave structure and the high-phase flat-gate meander waveguide slow-wave structure

[0108]

[0109] The simulation structures of the low-phase flat-gate meander waveguide and the high-phase flat-gate meander waveguide in Table 1 are as Figure 3 shown.

[0110] Among them, Figure 3 (a) is the three-dimensional vacuum model of the flat-gate meander waveguide; Figure 3 (b) is the front view of the flat-gate meander waveguide; Figure 3 (c) is the solid model of the high-phase flat-gate meander waveguide; Figure 3(d) is the solid model of the low-phase planar grating meander waveguide.

[0111] Then, the performance of the two types of planar grating meander waveguides in Figure 3 will be described.

[0112] Figure 3 Show the vacuum model of the planar grating meander waveguide, waveguide wide side - a, period length - p, total slow-wave height - h, waveguide slot width - g, planar grating grid width - w, planar grating grid height - d, channel radius - r. The fundamental mode field pattern of the planar grating meander waveguide is the quasi-TE10 mode. When operating in the high-phase part, the cut-off frequency of the fundamental mode is lower than that in the low-phase part. According to the size co-transition effect, during the process of moving the working section from the low-phase section to the high-phase section, not only the size of the waveguide wide side a needs to be increased, but also each size needs to be increased.

[0113] Figure 4 Show the comparison of the normalized phase velocity between high-phase operation and low-phase operation. In order to enable the low-phase part of the planar grating meander waveguide traveling-wave tube to operate in the range of 650 - 670 GHz, a group of low-phase planar grating meander waveguide slow-wave structures were optimized, and the normalized phase velocity is as shown by the orange curve in Figure 2 . Generally speaking, the working section of the low-phase planar grating meander waveguide (similar to the meander waveguide) is slightly higher than the low cut-off frequency. This structure exhibits relatively strong dispersion characteristics, with a steep curve trend, providing balanced amplification performance while restricting the working bandwidth. In order to enable the planar grating meander waveguide to operate from the low-phase part to the high-phase part while maintaining a similar normalized phase velocity in the same frequency range, the structure size must be appropriately increased. In this case, the limitations related to the size scaling effect will be effectively alleviated. According to the values listed in Table 1, the tunnel radius r remains unchanged during the comparison to ensure the evaluation of the slow-wave structure under the same electron optical system conditions. The sizes of a, p, h, g, and w are significantly increased. As shown in the local enlarged view, in the frequency range of 640 - 680 GHz, compared with the low-phase planar grating meander waveguide, the curve trend of the high-phase planar grating meander waveguide is flatter and the dispersion characteristics are weaker.

[0114] Figure 5 Show the comparison of ohmic losses. Considering the inevitable influence of surface roughness during the actual surface processing, in the simulation, the conductivity of high-conductivity oxygen-free copper is set to 2.0×10 7 S / m. As shown in Figure 4As shown by the orange curve, although the surface area of the high-phase flat-gate meandering waveguide is larger than that of the low-phase flat-gate meandering waveguide, its ohmic loss is significantly lower than that of the low-phase flat-gate meandering waveguide in the frequency range of 640 - 680 GHz. Specifically, at a frequency of 660 GHz, the ohmic losses of the low-phase flat-gate meandering waveguide and the high-phase flat-gate meandering waveguide are 0.14 dB and 0.28 dB respectively.

[0115] Figure 6 Shows the transmission characteristics of the slow-wave structure of the low-phase flat-gate meandering waveguide at 20 periods. Reflection coefficient S 11 Is less than -15 dB in the range of [637 GHz, -690 GHz], showing a good matching effect. Transmission coefficient S 21 Has a fluctuation of 4.76 dB in the region of 650 - 670 GHz, being -16.31 dB and -11.55 dB at 650 GHz and 670 GHz respectively.

[0116] Figure 7 Shows the transmission characteristics of the slow-wave structure of the high-phase flat-gate meandering waveguide at 20 periods. Reflection coefficient S 11 Is less than -15 dB in the range of [630 GHz, -675 GHz], showing a good matching effect. Transmission coefficient S 21 Has a fluctuation of 1.76 dB in the region of 650 - 670 GHz, being -5.91 dB and -7.67 dB at 650 GHz and 670 GHz respectively.

[0117] In summary, the high-phase flat-gate meandering waveguide effectively alleviates the problem of size reduction caused by the size scaling effect and exhibits good high-frequency characteristics, such as weak dispersion characteristics, a wider beam-wave synchronization region, and low ohmic loss. In the evaluation of transmission characteristics, the simulation results show that at the same number of periods, the insertion loss of the slow-wave structure of the high-phase flat-gate meandering waveguide is significantly reduced by more than 30%.

[0118] Example 2 also discloses a waveguide obtained by using a high-phase-based flat-gate meandering waveguide design method described in Example 1.

[0119] In some embodiments, slots are opened in the vertical direction perpendicular to the horizontal axis of the electron beam channel 3 in the flat-gate section and / or the bent-gate section of the upper row of gates 2 of the waveguide, and / or slots are opened in the vertical direction perpendicular to the horizontal axis of the electron beam channel 3 in the flat-gate section and / or the bent-gate section of the lower row of gates 1 of the waveguide, and the entire electron beam channel 3 passes through the grooves opened in the flat-gate section.

[0120] As Figures 8 - 10 shown.

[0121] In some embodiments, slots matching the electron beam channel 3 are formed in the flat grid sections of the upper row of grids 2 and the lower row of grids 1 of the waveguide.

[0122] As Figures 11 - 12 shown, the slots formed in the flat grid sections make the cross-sections of the electron channels on the upper row of grids and the lower row of grids be semi-circular respectively.

[0123] In some embodiments, the waveguide is an interleaved ridge-loaded waveguide or a symmetric ridge-loaded waveguide.

[0124] Specifically as Figures 14 - 15 shown.

[0125] Embodiment 3 discloses an application of a waveguide, using the waveguide described in Embodiment 2 for high-phase working dispersion combination and / or high-phase working phase velocity gradual change / jump and / or high-phase working phase regulation and / or high-phase working multi-electron beam channels and power synthesis.

[0126] Meanwhile, it should be noted that the materials and processing schemes of the waveguide of the present invention both adopt the prior art and will not be elaborated here.

[0127] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only the specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A design method for a flat grid meandering waveguide based on high phase, characterized in that Including: Obtaining first dispersion characteristic data in the form of a Brillouin diagram of a low-phase planar grating meander waveguide, the first dispersion characteristic data including a first low-phase working dispersion curve and a first high-phase non-working dispersion curve; Obtaining the working frequency range for the low-phase planar grating meander waveguide to transmit terahertz waves in a set frequency band, the working frequency range intersecting with the first low-phase working dispersion curve; Adjusting the dimensions of the low-phase planar grating meander waveguide to obtain a high-phase planar grating meander waveguide such that the working frequency range intersects with the high-phase working dispersion curve in the form of a Brillouin diagram of the high-phase planar grating meander waveguide.

2. A design method of a flat grid meandering waveguide based on high phase according to claim 1, characterized in that, Adjusting the dimensions of the low-phase planar grating meander waveguide includes adjusting one or more of the waveguide wide side a, period length p, waveguide slot width g, total slow-wave height h, planar grating gate width w, planar grating gate height d, and electron beam radius r.

3. A design method for a flat grid meandering waveguide based on high phase according to claim 1, characterized in that The specific method for adjusting the dimensions of the low-phase planar grating meander waveguide to obtain a high-phase planar grating meander waveguide is as follows: Setting the objective function as the coincidence degree of a specific line segment of the high-phase dispersion curve of the planar grating meander waveguide in the working area included in the working frequency range in the form of a Brillouin diagram; Determining the parameters to be adjusted, and adjusting the determined parameters to be adjusted through a parameter optimization algorithm so that the adjusted planar grating meander waveguide satisfies the objective function. The adjusted planar grating meander waveguide is the high-phase planar grating meander waveguide, and the high-phase dispersion curve of the high-phase planar grating meander waveguide is the high-phase working dispersion curve of the high-phase planar grating meander waveguide.

4. A design method of a flat grid meandering waveguide based on high phase according to claim 3, characterized in that, The specific process of adjusting the determined parameters to be adjusted through a parameter optimization algorithm is as follows: Taking the determined parameters to be adjusted as the optimization individuals corresponding to the parameter optimization algorithm, and then performing parameter optimization on the optimization individuals through the corresponding parameter optimization algorithm and the set objective function.

5. A design method of a flat grid meandering waveguide based on high phase according to claim 3, characterized in that, The specific line segment is a region within mπ before and after with the point having the minimum slope of the high-phase working dispersion curve of the high-phase planar grating meander waveguide as the midpoint, where m is a positive number.

6. A waveguide, characterized in that, Obtained by using the method for designing a planar grating meander waveguide based on high phase according to any one of claims 1-5.

7. The waveguide according to claim 6, characterized in that, Slotting is performed in the vertical direction perpendicular to the horizontal axis of the electron beam channel in the flat gate section and / or bent gate section of the upper row of gates of the waveguide, and / or slotting is performed in the vertical direction perpendicular to the horizontal axis of the electron beam channel in the flat gate section and / or bent gate section of the lower row of gates of the waveguide, and the entire electron beam channel passes through the groove opened in the flat gate section.

8. The waveguide according to claim 6, wherein Slots matching the electron beam channel are opened in the flat gate sections of the upper row of gates and the lower row of gates of the waveguide.

9. The waveguide according to claim 6, wherein, The waveguide is an interleaved ridge-loaded waveguide or a symmetric ridge-loaded waveguide.

10. An application of a waveguide, characterized in that, Using the waveguide according to any one of claims 7-9 for high-phase working dispersion combination and / or high-phase working phase velocity gradual change / jump and / or high-phase working phase control and / or high-phase working multi-electron beam channel and power synthesis.

Images