Energy transmission coupling structure suitable for symmetric double-groove coupling cavity slow wave structure

Abstract

The invention provides an energy transmission coupling structure suitable for a symmetric double-groove coupling cavity slow wave structure. The energy transmission coupling structure comprises a gradual change waveguide section used for being connected with the symmetric double-groove coupling cavity slow wave structure. The gradient waveguide section comprises a plurality of cavity units of a periodic structure and an electron beam channel located at the central axis position of the cavity units. The cavity unit comprises two straight waveguide cavities and two connecting cavities located between the two straight waveguide cavities. The two connecting cavities are symmetrically arranged relative to the electron beam channel and are communicated with the two straight waveguide cavities along the axial direction of the electron beam channel; the straight waveguide cavities of the adjacent cavity units are communicated; the straight waveguide cavity height, the straight waveguide cavity narrow edge length and the period length of the cavity units which are sequentially communicated are gradually increased from one end, used for being connected with the symmetric double-groove coupling cavity slow wave structure, of the energy transmission coupling structure. The energy transmission coupling structure can solve the problem that an existing energy transmission coupling structure is relatively narrow in bandwidth, and the working performance of a symmetric double-groove coupling cavity slow wave structure is affected.

Description

Technical Field

[0001] The present invention relates to the field of vacuum electronic technology, and more specifically, to an energy transmission coupling structure suitable for a symmetrical double-slot coupled cavity slow-wave structure. Background Art

[0002] Millimeter wave / terahertz technology has important application value in future communications, imaging, radar and other fields. The main obstacle restricting its development is the lack of broadband coherent radiation sources with compact structure and moderate power level. The traveling wave tube is a vacuum electronic device that can generate or amplify millimeter wave / terahertz signals. Compared with other types of devices, the traveling wave tube is one of the few devices that has wide bandwidth, high gain, high power capability and compact structure in both millimeter wave and terahertz frequency bands. Traditional traveling wave tube devices are limited by the size co-transition effect, that is, as the frequency increases, the output power decreases with the square of the frequency, which greatly limits the ability of the traveling wave tube to work in the high frequency band. Band electron injection technology is an effective technical way to overcome this problem, and is currently one of the research hotspots in the field of terahertz vacuum electronic devices.

[0003] The symmetrical double-slot coupled cavity slow-wave structure is an all-metal slow-wave structure suitable for strip electron beams. It has the advantages of large electron beam channels and high coupling impedance. Its basic structure is as follows: Figure 1 As shown. Although the electromagnetic wave propagation path and the electron beam transmission path in the symmetrical double-slot coupled cavity slow-wave structure are separated from each other, which is conducive to the feeding and extraction of the electromagnetic field, it is relatively difficult to widen the bandwidth of the slow-wave structure due to the existence of the coupled cavity structure, which requires complex design. The existing energy transmission coupling structure has a relatively narrow bandwidth, which will affect the working performance of the symmetrical double-slot coupled cavity slow-wave structure when used. Summary of the invention

[0004] In view of the above problems, the present invention provides an energy transmission coupling structure suitable for a symmetrical double-slot coupled cavity slow-wave structure to solve the problem that the bandwidth of the existing energy transmission coupling structure is relatively narrow, which will affect the working performance of the symmetrical double-slot coupled cavity slow-wave structure.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides an energy transmission coupling structure suitable for a symmetrical double-slot coupled cavity slow-wave structure, comprising: a gradually changing waveguide section connected to the symmetrical double-slot coupled cavity slow-wave structure; the gradually changing waveguide section comprises a plurality of cavity units of a periodic structure and an electron injection channel located at the center axis of the cavity unit;

[0007] The cavity unit comprises two straight waveguide cavities and two connecting cavities located between the two straight waveguide cavities; the two connecting cavities are symmetrically arranged relative to the electron injection channel and are connected to the two straight waveguide cavities along the axial direction of the electron injection channel; the straight waveguide cavities of adjacent cavity units are connected;

[0008] Starting from one end of the energy transmission coupling structure used to connect with the symmetrical double-slot coupled cavity slow-wave structure, the straight waveguide cavity height, the straight waveguide cavity narrow side length and the period length of the cavity units connected in sequence gradually increase.

[0009] The preferred solution is that starting from one end connected to the symmetrical double-slot coupled cavity slow-wave structure, the straight waveguide cavity height, the straight waveguide cavity narrow side length and the period length of the cavity units connected in sequence gradually increase in a linear manner.

[0010] A preferred solution is that the two straight waveguide cavities of the same cavity unit have the same structural dimensions, and the two connecting cavities of the same cavity unit have the same structural dimensions.

[0011] The preferred solution is that the height of the straight waveguide cavity of the first cavity unit connected to the slow-wave structure is h1, the narrow side length of the straight waveguide cavity is d1, and the period length is p1; the height of the straight waveguide cavity of the nth cavity unit is h n , the narrow side length of the straight waveguide cavity is d n , the period length is p n ; The height of the straight waveguide cavity of the last cavity unit is h N , the narrow side length of the straight waveguide cavity is d N , the period length is p N ; The number of cavity units is N;

[0012] The height of the straight waveguide cavity, the narrow side length and the period length of the straight waveguide cavity of the nth cavity unit satisfy the following relations:

[0013] h n =h1+n(h N -h1) / (N+1);

[0014] d n =d1+n(d N -d1) / (N+1);

[0015] p n =p1+n(p N -p1) / (N+1).

[0016] A preferred solution is that the energy transmission coupling structure further includes a connecting waveguide section;

[0017] The connecting waveguide section comprises a coupling cavity connected to a straight waveguide cavity of an energy transmission coupling structure away from a slow-wave structure, and a standard waveguide connected to the coupling cavity; the coupling cavity and the connected straight waveguide cavity have the same structural dimensions; the coupling cavity and the standard waveguide are coaxially arranged, and the axis is perpendicular to the axis of the electron injection channel.

[0018] A preferred solution is that the electron injection channel is a channel with a rectangular cross-section.

[0019] Preferably, the energy transmission coupling structure is an input coupling structure or an output coupling structure.

[0020] The present invention also provides a slow-wave circuit, comprising a symmetrical double-slot coupled cavity slow-wave structure and the energy transmission coupling structure as described above; the energy transmission coupling structure is connected to the input end and / or output end of the symmetrical double-slot coupled cavity slow-wave structure; the cavity unit connected to the input end of the symmetrical double-slot coupled cavity slow-wave structure has the same structural dimensions as the single-period symmetrical double-slot coupled cavity slow-wave structure and / or the cavity unit connected to the output end of the symmetrical double-slot coupled cavity slow-wave structure has the same structural dimensions as the single-period symmetrical double-slot coupled cavity slow-wave structure.

[0021] The present invention also provides a design method for an energy transmission coupling structure suitable for a symmetrical double-slot coupled cavity slow-wave structure, comprising the following steps: designing a gradually changing waveguide section for connecting to the symmetrical double-slot coupled cavity slow-wave structure; the gradually changing waveguide section comprises a plurality of cavity units of a periodic structure and an electron injection channel located at the center axis of the cavity unit; the cavity unit comprises two straight waveguide cavities and two connecting cavities located between the two straight waveguide cavities; the two connecting cavities are symmetrically arranged relative to the electron injection channel and are connected to the two straight waveguide cavities along the axial direction of the electron injection channel; the straight waveguide cavities of adjacent cavity units are connected;

[0022] Using three-dimensional electromagnetic field simulation software, starting from one end of the energy transmission coupling structure used to connect to the symmetrical double-slot coupled cavity slow-wave structure, the straight waveguide cavity height, straight waveguide cavity narrow side length and period length of the cavity units connected in sequence are designed to gradually increase.

[0023] The preferred solution is to gradually increase the period length of the energy transmission coupling structure to balance the influence of the straight waveguide cavity height and the straight waveguide cavity narrow side length on the structural characteristic impedance, so that the overall impedance of the energy transmission coupling structure changes smoothly and gradually, thereby improving the matching performance of the energy transmission coupling structure.

[0024] The beneficial effects of the present invention are:

[0025] The present invention can greatly broaden the structural bandwidth and optimize the structural electromagnetic performance. Between 205.5GHz and 222.5GHz, the S 11 The bandwidth with parameters below -15dB can reach 17GHz, and the relative bandwidth is 8%, which can fully meet the requirements of the symmetrical double-slot coupled cavity slow-wave structure for the working bandwidth of the matching structure.

[0026] The present invention realizes H-plane matching extraction, which can prevent electromagnetic waves from leaking through the electron injection channel without using a reflector, thereby improving the longitudinal compactness of the structure. In the transverse direction, the matching output is achieved by only one gradient waveguide section, and the transverse compactness is high. 31 The parameter value is below -150dB, which means the leakage is within 10 -15 The straight waveguide cavity height, the straight waveguide cavity narrow side length and the period length of the energy transmission coupling structure cavity unit of the present invention are all linearly transitioned, so it has a high degree of design flexibility. The symmetrical double-slot coupled cavity slow-wave structure with different size parameters and its bandwidth requirements can be achieved by flexibly adjusting the gradient parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0028] Figure 1 It is a structural schematic diagram of a single-period symmetrical double-slot coupled cavity slow-wave structure.

[0029] Figure 2A It is a schematic diagram of the overall structure of the energy transmission coupling structure of the present invention.

[0030] Figure 2B It is a schematic structural diagram of the gradient waveguide section of the present invention.

[0031] Figure 3 is the S corresponding to the present invention 11 Performance parameter graph.

[0032] Figure 4 is the S corresponding to the present invention 31 Performance parameter graph.

[0033] Figure 5 It is a curve diagram showing the influence of gradual change of period length size on impedance of the present invention.

[0034] Figure numerals: 1. gradient waveguide section, 2. coupling cavity, 3. standard waveguide, 11. electron beam channel, 12. straight waveguide cavity, 13. connecting cavity, 101. first cavity unit, 102. second cavity unit, 103. third cavity unit. DETAILED DESCRIPTION

[0035] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0036] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0037] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0038] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0039] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0040] Due to the limitation of processing methods in the terahertz frequency band, the input and output structures should be all-metal waveguide structures and be processable. The structure must have sufficient bandwidth to meet the performance requirements of the symmetrical double-slot coupled cavity slow-wave structure. In order not to increase the complexity of the magnetic field design, it should be led out from the H-plane and the length should be as short as possible.

[0041] In order to solve the problem that the existing coupling structure is difficult to achieve bandwidth widening, which affects the working performance of the symmetrical double-slot coupled cavity slow-wave structure. The present invention provides an energy transmission coupling structure suitable for the symmetrical double-slot coupled cavity slow-wave structure, combined with Figures 1 to 5As shown, the energy transmission coupling structure suitable for the symmetrical double-slot coupled cavity slow-wave structure specifically comprises: a gradually changing waveguide section 1 for connecting with the symmetrical double-slot coupled cavity slow-wave structure; the gradually changing waveguide section 1 comprises a plurality of cavity units of a periodic structure and an electron injection channel 11 located at the center axis of the cavity unit; the cavity unit comprises two straight waveguide cavities 12 and two connecting cavities 13 located between the two straight waveguide cavities 12; the two connecting cavities 13 are symmetrically arranged relative to the electron injection channel 11 and connect the two straight waveguide cavities 12 along the axial direction of the electron injection channel 11; the straight waveguide cavities 12 of adjacent cavity units are connected; starting from one end of the energy transmission coupling structure for connecting with the symmetrical double-slot coupled cavity slow-wave structure, the straight waveguide cavity height h, the straight waveguide cavity narrow side length d and the period length p of the cavity units connected in sequence gradually increase. The cavity unit of the energy transmission coupling structure of the present invention has the same structural appearance as the single-period symmetrical double-slot coupled cavity slow-wave structure. It should be noted that the cavity units of the present invention are consistent in shape and arranged according to a certain rule, and even if they are of different sizes, they can be considered to constitute a periodic structure. Furthermore, the two straight waveguide cavities of the same cavity unit have the same structural dimensions, and the two connecting cavities of the same cavity unit have the same structural dimensions. The present invention has a compact structure and a wide bandwidth, which can meet practical requirements and achieve good matching, reflection and isolation characteristics.

[0042] The present invention selects the straight waveguide cavity height h, the straight waveguide cavity narrow side length d and the period length p of the cavity unit of the periodic structure to be gradually changed. The straight waveguide cavity height h and the straight waveguide cavity narrow side length d are selected to be gradually changed in order to make the size of the coupled cavity similar to that of the standard waveguide in size, thereby reducing the return loss caused by the sudden change of the lateral size between the coupled cavity and the standard waveguide.

[0043] The gradual change of the period length p is chosen to balance the influence of the gradual change of the straight waveguide cavity height h and the straight waveguide cavity narrow side length d on the structural characteristic impedance, so that the overall impedance can be smoothly changed to achieve the best matching effect. Figure 5 As shown, it describes the influence of the gradual change of the period length p on the impedance. It can be seen that the impedance changes smoothly.

[0044] In a specific embodiment, starting from one end connected to the symmetrical double-slot coupled cavity slow-wave structure, the straight waveguide cavity height h, the straight waveguide cavity narrow side length d and the period length p of the cavity units connected in sequence all gradually increase in a linear law. The energy transmission coupling structure is an input coupling structure or an output coupling structure. When the energy transmission coupling structure is an input coupling structure, it is connected to the input end of the symmetrical double-slot coupled cavity slow-wave structure to realize the input of the microwave signal into the symmetrical double-slot coupled cavity slow-wave structure. When the energy transmission coupling structure is an output coupling structure, it is connected to the output end of the symmetrical double-slot coupled cavity slow-wave structure to realize the output of the microwave signal from the symmetrical double-slot coupled cavity slow-wave structure to the outside.

[0045] More specifically, the height of the straight waveguide cavity of the first cavity unit connected to the symmetrical double-slot coupled cavity slow-wave structure is h1, the narrow side length of the straight waveguide cavity is d1, and the period length is p1; the height of the straight waveguide cavity of the nth cavity unit is h n , the narrow side length of the straight waveguide cavity is d n , the period length is p n ; The height of the straight waveguide cavity of the last cavity unit is h N , the narrow side length of the straight waveguide cavity is d N , the period length is p N ; The number of cavity units is N, which can be selected according to the required bandwidth size, and the selection range can be 2-4. The height of the straight waveguide cavity, the narrow side length of the straight waveguide cavity and the period length of the nth cavity unit respectively satisfy the following relationship: h n =h1+n(h N -h1) / (N+1); d n =d1+n(d N -d1) / (N+1); p n =p1+n(p N -p1) / (N+1).

[0046] Combination Figure 2B As shown, there are three cavity units, which are the first cavity unit 101, the second cavity unit 102 and the third cavity unit 103 from left to right. The three cavity units have the same structural appearance and the straight waveguide cavity height h, the straight waveguide cavity narrow side length d and the period length p gradually increase from the first cavity unit 101 to the third cavity unit 103. The first cavity unit 101 is connected to the symmetrical double-slot coupled cavity slow-wave structure, and the third cavity unit 103 is connected to the coupled cavity. The two straight waveguide cavities of the first cavity unit 101 have the same structural dimensions, and the two connected cavities of the first cavity unit 101 have the same structural dimensions. The two straight waveguide cavities of the second cavity unit 102 have the same structural dimensions, and the two connected cavities of the second cavity unit 102 have the same structural dimensions. The two straight waveguide cavities of the third cavity unit 103 have the same structural dimensions, and the two connected cavities of the third cavity unit 103 have the same structural dimensions.

[0047] In a specific embodiment, the energy transmission coupling structure further includes a connecting waveguide section; the connecting waveguide section includes a coupling cavity 2 connected to a straight waveguide cavity 12 of the symmetrical double-slot coupled cavity slow-wave structure and a cavity unit of the energy transmission coupling structure away from the symmetrical double-slot coupled cavity slow-wave structure, and a standard waveguide 3 connected to the coupling cavity 2. The coupling cavity 2 has the same structural dimensions as the connected straight waveguide cavity 12, and the coupling cavity 2 is coaxially arranged with the standard waveguide 3, and the axis is perpendicular to the axis of the electron injection channel. The present invention uses a linearly gradual gradual waveguide section 1 coupled with the connecting waveguide section to achieve input and output matching of the electromagnetic field of the symmetrical double-slot coupled cavity slow-wave structure. From the end connected to the slow-wave structure, the straight waveguide cavity height h and the straight waveguide cavity narrow side length d of the energy transmission coupling structure gradually increase from the same size as the corresponding size of the single-period symmetrical double-slot coupled cavity slow-wave structure until they are the same size as the corresponding size of the coupling cavity 2, so as to achieve matching connection between the symmetrical double-slot coupled cavity slow-wave structure and the coupling cavity 2, and at the same time, the period length p gradually increases. The coupling cavity 2 is used to connect the gradual waveguide section 1 and the standard waveguide 3, realize the transmission of electromagnetic energy from the symmetrical double-slot coupling cavity slow-wave structure to the standard waveguide 3, and play a role in impedance matching. Since the direction of the electric field in the coupling cavity 2 is the same as the direction of the electron beam transmission, electromagnetic transmission cannot be stimulated in the electron beam channel, and the electromagnetic field is cut off along the direction of the electron beam channel, and the electromagnetic field will not leak from the electron beam channel. The electron beam channel 11 is a rectangular cross-section channel, and the structural dimensions of the electron beam channel 11 of the energy transmission coupling structure of the present invention remain unchanged.

[0048] In a specific embodiment, the straight waveguide cavity height of the first cavity unit of the tapered waveguide section 1 connected to the symmetrical double-slot coupled cavity slow-wave structure is h1, the straight waveguide cavity narrow side length is d1, and the period length is p1. The straight waveguide cavity height of the last cavity unit of the tapered waveguide section 1 connected to the coupled cavity 2 is h N , the narrow side length of the straight waveguide cavity is d N , the period length is p N ; The number of cavity units is N. The following is a set of specific values ​​of the above parameters (unit: mm): h1 = 0.72, d1 = 0.34, p1 = 0.46, h N =0.78, d N =0.3, p N = 0.3, N = 3. A set of dimension parameters (unit: mm) of the coupling cavity 2 and the standard waveguide 3 are given: the coupling cavity wide side length = 0.6, the coupling cavity narrow side length = 0.33, the coupling cavity height = 0.78, the standard waveguide height = 1.092, and the standard waveguide width = 0.546.

[0049] Due to the electromagnetic characteristics of the coupled cavity structure in the symmetrical double-slot coupled cavity slow-wave structure, the bandwidth of the structure is relatively narrow, and it is difficult to increase the bandwidth design. The use of the gradient waveguide section 1 of the present invention can greatly broaden the structure bandwidth and optimize the electromagnetic performance of the structure.

[0050] Reference Figure 3 It can be seen that between 205.5GHz and 222.5GHz, S 11 The parameter is lower than -15dB, the bandwidth can reach 17GHz, and the relative bandwidth is 8%. This can fully meet the requirements of the symmetrical double-slot coupled cavity slow-wave structure for the working bandwidth of the matching structure. Compared with the 8% relative matching bandwidth of the present invention, the relative matching bandwidth of the existing non-gradient input and output coupling structure does not exceed 2%.

[0051] Since the present invention realizes H-plane matching extraction, it can prevent electromagnetic waves from leaking through the electron injection channel without using a reflector. Figure 5 It can be seen that S 31 The parameter value is below -150dB, which means the leakage is about 10 -15 Below the level.

[0052] The present invention also provides a slow-wave circuit, comprising a symmetrical double-slot coupled cavity slow-wave structure and the energy transmission coupling structure as described above; the energy transmission coupling structure is connected to the input end and / or output end of the symmetrical double-slot coupled cavity slow-wave structure; the cavity unit connected to the input end of the symmetrical double-slot coupled cavity slow-wave structure has the same structural dimensions as the single-period symmetrical double-slot coupled cavity slow-wave structure and / or the cavity unit connected to the output end of the symmetrical double-slot coupled cavity slow-wave structure has the same structural dimensions as the single-period symmetrical double-slot coupled cavity slow-wave structure.

[0053] The present invention also provides a design method for an energy transmission coupling structure suitable for a symmetrical double-slot coupled cavity slow-wave structure, the design method comprising the following steps: designing a gradually changing waveguide section 1 for connecting to the symmetrical double-slot coupled cavity slow-wave structure; the gradually changing waveguide section 1 comprises a plurality of cavity units of a periodic structure and an electron injection channel 11 located at the center axis of the cavity unit; the cavity unit comprises two straight waveguide cavities 12 and two connecting cavities 13 located between the two straight waveguide cavities 12; the two connecting cavities 13 are symmetrically arranged relative to the electron injection channel 11 and are connected to the two straight waveguide cavities 12 along the axial direction of the electron injection channel; the straight waveguide cavities 12 of adjacent cavity units are connected; using three-dimensional electromagnetic field simulation software, starting from one end of the energy transmission coupling structure for connecting to the symmetrical double-slot coupled cavity slow-wave structure, the straight waveguide cavity height h, the straight waveguide cavity narrow side length d and the period length p of the cavity units connected in sequence are designed to gradually increase.

[0054] Furthermore, by gradually increasing the period length p of the energy transmission coupling structure, the influence of the straight waveguide cavity height h and the straight waveguide cavity narrow side length d gradually increasing on the structural characteristic impedance is balanced, so that the overall impedance of the energy transmission coupling structure can be smoothly changed, thereby improving the matching performance of the energy transmission coupling structure.

[0055] In summary, the present invention can greatly broaden the structural bandwidth and optimize the structural electromagnetic performance. Between 205.5GHz-222.5GHz, the corresponding S 11 The bandwidth with parameters below -15dB can reach 17GHz, and the relative bandwidth is 8%. It can fully meet the requirements of the symmetrical double-slot coupled cavity slow-wave structure for the working bandwidth of the matching structure. In addition, the present invention realizes H-plane matching extraction, which can prevent the leakage of electromagnetic waves through the electron injection channel without using a reflector, thereby improving the longitudinal compactness of the structure. In the transverse direction, the matching output is achieved by only one gradient waveguide section, and its transverse compactness is high. The S-type waveguide of the present invention is used to reflect the degree of leakage of the structure input signal from the electron injection channel. 31 The parameter value is below -150dB, which means the leakage is within 10 -15 The straight waveguide cavity height, the straight waveguide cavity narrow side length and the period length of the energy transmission coupling structure cavity unit of the present invention are all linearly transitioned, so it has a high degree of design flexibility. The symmetrical double-slot coupled cavity slow-wave structure with different size parameters and its bandwidth requirements can be achieved by flexibly adjusting the gradient parameters.

[0056] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. An energy transmission coupling structure suitable for a symmetrical double-slot coupled cavity slow-wave structure, characterized in that: include: A gradually changing waveguide section connected to the symmetrical double-slot coupled cavity slow-wave structure; the gradually changing waveguide section comprises a plurality of cavity units of a periodic structure and an electron injection channel located at the center axis of the cavity unit; The cavity unit comprises two straight waveguide cavities and two connecting cavities located between the two straight waveguide cavities; the two connecting cavities are symmetrically arranged relative to the electron injection channel and are connected to the two straight waveguide cavities along the axial direction of the electron injection channel; the straight waveguide cavities of adjacent cavity units are connected; Starting from one end of the energy transmission coupling structure used to connect with the symmetrical double-slot coupled cavity slow-wave structure, the straight waveguide cavity height, the straight waveguide cavity narrow side length and the period length of the cavity units connected in sequence gradually increase.

2. The energy transmission coupling structure suitable for a symmetrical double-slot coupled cavity slow-wave structure according to claim 1, characterized in that: Starting from one end connected to the symmetrical double-slot coupled cavity slow-wave structure, the straight waveguide cavity height, the straight waveguide cavity narrow side length and the period length of the cavity units connected in sequence gradually increase in a linear manner.

3. The energy transmission coupling structure suitable for a symmetrical double-slot coupled cavity slow-wave structure according to claim 1, characterized in that: The two straight waveguide cavities of the same cavity unit have the same structural dimensions, and the two connecting cavities of the same cavity unit have the same structural dimensions.

4. The energy transmission coupling structure suitable for a symmetrical double-slot coupled cavity slow-wave structure according to claim 1, characterized in that: The height of the straight waveguide cavity of the first cavity unit connected to the slow-wave structure is h1, the narrow side length of the straight waveguide cavity is d1, and the period length is p1; the height of the straight waveguide cavity of the nth cavity unit is h n , the narrow side length of the straight waveguide cavity is d n , the period length is p n ; The height of the straight waveguide cavity of the last cavity unit is h N , the narrow side length of the straight waveguide cavity is d N , the period length is p N ; The number of cavity units is N; The height of the straight waveguide cavity, the narrow side length and the period length of the straight waveguide cavity of the nth cavity unit satisfy the following relations: h n =h1+n(h N -h1) / (N+1); d n =d1+n(d N -d1) / (N+1); p n =p1+n(p N -p1) / (N+1).

5. The energy transmission coupling structure applicable to the symmetrical double-slot coupled cavity slow-wave structure according to claim 1, characterized in that: The energy transmission coupling structure also includes a connecting waveguide section; The connecting waveguide section comprises a coupling cavity connected to a straight waveguide cavity of an energy transmission coupling structure away from a slow-wave structure, and a standard waveguide connected to the coupling cavity; the coupling cavity and the connected straight waveguide cavity have the same structural dimensions; the coupling cavity and the standard waveguide are coaxially arranged, and the axis is perpendicular to the axis of the electron injection channel.

6. The energy transmission coupling structure applicable to the symmetrical double-slot coupled cavity slow-wave structure according to claim 1, characterized in that: The electron injection channel is a rectangular cross-section channel.

7. The energy transmission coupling structure applicable to the symmetrical double-slot coupled cavity slow-wave structure according to claim 1, characterized in that: The energy transmission coupling structure is an input coupling structure or an output coupling structure.

8. A slow wave circuit, characterized in that: It comprises a symmetrical double-slot coupled cavity slow-wave structure and an energy transmission coupling structure as described in any one of claims 1 to 7; the energy transmission coupling structure is connected to the input end and / or output end of the symmetrical double-slot coupled cavity slow-wave structure; the cavity unit connected to the input end of the symmetrical double-slot coupled cavity slow-wave structure has the same structural dimensions as a single-period symmetrical double-slot coupled cavity slow-wave structure and / or the cavity unit connected to the output end of the symmetrical double-slot coupled cavity slow-wave structure has the same structural dimensions as a single-period symmetrical double-slot coupled cavity slow-wave structure.

9. A design method for an energy transmission coupling structure suitable for a symmetrical double-slot coupled cavity slow-wave structure, characterized in that: The following steps are involved: A gradually changing waveguide section designed to be connected to a symmetrical double-slot coupled cavity slow-wave structure; the gradually changing waveguide section comprises a plurality of cavity units of a periodic structure and an electron injection channel located at the center axis of the cavity unit; the cavity unit comprises two straight waveguide cavities and two connecting cavities located between the two straight waveguide cavities; the two connecting cavities are symmetrically arranged relative to the electron injection channel and are connected to the two straight waveguide cavities along the axial direction of the electron injection channel; the straight waveguide cavities of adjacent cavity units are connected; Using three-dimensional electromagnetic field simulation software, starting from one end of the energy transmission coupling structure used to connect to the symmetrical double-slot coupled cavity slow-wave structure, the straight waveguide cavity height, straight waveguide cavity narrow side length and period length of the cavity units connected in sequence are designed to gradually increase.

10. The design method according to claim 9, characterized in that: By gradually increasing the period length of the energy transmission coupling structure, the influence of the straight waveguide cavity height and the straight waveguide cavity narrow side length gradually increasing on the structural characteristic impedance is balanced, so that the overall impedance of the energy transmission coupling structure changes smoothly and gradually, and the matching performance of the energy transmission coupling structure is improved.

Images