A sinusoidal interleaved double-gate slow-wave structure

Abstract

The invention discloses a sinusoidal staggered double-grid slow-wave structure, which relates to the field of vacuum electronic technology and solves the problems of large transmission loss and narrow bandwidth of the existing slow-wave structure. The key points of the technical solution are: comprising an upper grid portion and a lower grid portion respectively arranged on the upper and lower sides, the upper grid portion and the lower grid portion both form sinusoidal protrusions at equal intervals along the axial direction to form a periodic waveguide curve, and the periodic waveguide curve of the upper grid portion and the periodic waveguide curve of the lower grid portion have a phase difference; the mutation point in the field of the traditional rectangular protrusion is reduced by the smooth sinusoidal protrusion, thereby reducing the loss of electromagnetic waves in the transmission process, and the sinusoidal protrusions of the upper and lower grid portions are staggered, which has a higher bandwidth than the traditional staggered double-grid slow-wave structure, and provides a traveling wave tube slow-wave structure with improved output power for submillimeter wave bands and terahertz wave bands.

Description

Technical Field

[0001] The invention relates to the field of vacuum electronic technology, and more specifically, to a sinusoidal staggered double-grid slow-wave structure. Background Art

[0002] Terahertz technology is the hottest research direction in the field of electronic science at home and abroad since the new century. It is an interdisciplinary subject jointly influenced by electronics and photonics. Terahertz waves have completely different electromagnetic radiation characteristics from microwaves and visible light, and have great application prospects in many fields such as biomedicine, electronic countermeasures, long-distance communications, non-destructive testing, and astronomy.

[0003] In the terahertz band, vacuum electronic devices are a common high-power radiation source. Among the existing vacuum electronic devices, the traveling wave tube has the advantages of high efficiency, high gain, and wide operating bandwidth. It is a traditional "O" type device, and the slow wave structure is the core component of the entire traveling wave tube. With the increase of operating frequency, the problems of large transmission loss, narrow bandwidth, and strong reflection of the slow wave structure in the terahertz band have become the decisive factors restricting the development of "O" type devices in the terahertz band. Therefore, it is urgent to explore a new type of slow wave structure to overcome the problems of large transmission loss and narrow bandwidth of the traditional slow wave structure, so as to promote the development of high-power radiation sources in the terahertz band. Summary of the invention

[0004] The purpose of the present application is to provide a sinusoidal staggered double-grid slow-wave structure to overcome the problems of large transmission loss and narrow bandwidth of the existing slow-wave structure.

[0005] The above technical purpose of the present application is achieved through the following technical scheme: including an upper gate portion and a lower gate portion respectively arranged on the upper and lower sides, the upper gate portion and the lower gate portion both form sinusoidal protrusions at equal intervals along the axial direction to form a periodic waveguide curve, and the periodic waveguide curve of the upper gate portion has a phase difference with the periodic waveguide curve of the lower gate portion.

[0006] By adopting the above technical solution, the mutation points in the field of the traditional rectangular protrusion are reduced by smooth sinusoidal protrusions, thereby reducing the loss of electromagnetic waves in the transmission process. The sinusoidal protrusions on the upper and lower grid parts are staggered, which has a higher bandwidth than the traditional slow-wave structure, and provides a traveling wave tube slow-wave structure with improved output power for the submillimeter wave band and the terahertz band.

[0007] Furthermore, the periodic waveguide curve of the upper gate portion and the periodic waveguide curve of the lower gate portion have a phase difference of half a period.

[0008] Furthermore, the boundary of the sinusoidal protrusion is a half-period sinusoidal curve.

[0009] Furthermore, the width of the upper gate portion and the lower gate portion is a, and the height is b, the period of the periodic waveguide curve is p, the width of the sinusoidal protrusion is a, the height is h, and the thickness is d, the spacing between two adjacent sinusoidal waveguides is L, and the height of the electron beam channel is hb; wherein, b=2h+hb, p=L+d, hb≤b / 4.

[0010] Furthermore, L=2d, p=3d.

[0011] Further, a=0.5 mm, b=0.51 mm, p=0.315 mm.

[0012] Further, h=0.21 mm, d=0.105 mm, L=0.21 mm, hb=0.09 mm.

[0013] Furthermore, the upper grid portion and the lower grid portion are made of metal.

[0014] With the above technical solution, the upper grid part and the lower grid part are made of metal, the sinusoidal protrusion has higher structural strength and greater power capacity, and the metal is easier to dissipate heat and is suitable for working in high frequency bands.

[0015] Furthermore, the sinusoidal protrusion is formed by milling.

[0016] On the other hand, the present application provides a traveling wave tube, comprising a sinusoidal interleaved double-grid slow-wave structure as described above.

[0017] By adopting the above technical solution, the traveling wave tube includes the above slow wave structure, which can expand the bandwidth and reduce the transmission loss, thereby improving the output power in the terahertz band.

[0018] Compared with the prior art, this application has the following beneficial effects:

[0019] 1. The main part of the sinusoidal staggered double-grid slow-wave structure is a smooth sinusoidal bulge, which reduces the mutation point of the field in the slow-wave structure, thereby reducing the loss of electromagnetic waves during transmission. The sinusoidal bulge is a complete half-period sine curve, with low transmission loss and easy processing;

[0020] 2. Compared with the conventional interlaced double-gate slow-wave structure, the bandwidth of the sinusoidal interlaced double-gate slow-wave structure has been effectively improved;

[0021] 3. The sinusoidal staggered double-grid slow-wave structure is an all-metal slow-wave structure. The sinusoidal raised structure has higher strength, greater power capacity, easier heat dissipation, and is suitable for working in high-frequency bands. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0023] Figure 1 It is a schematic diagram of a sinusoidal interleaved double-grid slow-wave structure;

[0024] Figure 2 It is a side view of the sinusoidal interleaved double-grid slow-wave structure;

[0025] Figure 3 This is the main view of the sinusoidal staggered double-grid slow-wave structure;

[0026] Figure 4 It is the comparison of the Brillouin diagrams of the sinusoidal staggered double-gate slow-wave structure, the conventional staggered double-gate slow-wave structure, and the segmented sinusoidal waveguide slow-wave structure;

[0027] Figure 5 It is the comparison of dispersion curves between the sinusoidal staggered double-grid slow-wave structure, the conventional staggered double-grid slow-wave structure, and the segmented sinusoidal waveguide slow-wave structure;

[0028] Figure 6 It is the high frequency transmission characteristic of the sinusoidal interleaved double-grid slow-wave structure;

[0029] Figure 7 It is the comparison of S21 curves of sinusoidal staggered double-gate slow-wave structure, conventional staggered double-gate slow-wave structure and segmented sinusoidal waveguide slow-wave structure;

[0030] Figure 8 It is a comparison of the transmission loss of the sinusoidal staggered double-grid slow-wave structure, the conventional staggered double-grid slow-wave structure, and the segmented sinusoidal waveguide slow-wave structure;

[0031] Fig. 9 It is a schematic diagram of a conventional staggered double-gate slow-wave structure;

[0032] Fig.10 It is a schematic diagram of the piecewise sinusoidal waveguide slow-wave structure;

[0033] Marks and corresponding parts names in the attached drawings:

[0034] 1. Upper grid; 2. Lower grid; 3. Sinusoidal protrusion; 4. Electron injection channel. DETAILED DESCRIPTION

[0035] Hereinafter, the term "include" or "may include" used in various embodiments of the present application indicates the presence of the function, operation or element applied for, and does not limit the increase of one or more functions, operations or elements. In addition, as used in various embodiments of the present application, the terms "include", "have" and their cognates are intended only to indicate specific features, numbers, steps, operations, elements, components or a combination of the foregoing items, and should not be understood as first excluding the presence of one or more other features, numbers, steps, operations, elements, components or a combination of the foregoing items or the possibility of increasing one or more features, numbers, steps, operations, elements, components or a combination of the foregoing items.

[0036] In various embodiments of the present application, the expression "or" or "at least one of B or / and C" includes any combination or all combinations of the words listed at the same time. For example, the expression "B or C" or "at least one of B or / and C" may include B, may include C, or may include both B and C.

[0037] The expressions (such as "first", "second", etc.) used in the various embodiments of the present application may modify the various constituent elements in the various embodiments, but may not limit the corresponding constituent elements. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only used for the purpose of distinguishing one element from other elements. For example, the first user device and the second user device indicate different user devices, although both are user devices. For example, without departing from the scope of the various embodiments of the present application, the first element may be referred to as the second element, and similarly, the second element may also be referred to as the first element.

[0038] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0039] It should be noted that if it is described that one component element is “connected” to another component element or is “connected to” another component element, the first component element may be directly connected to the second component element, and a third component element may be “connected” between the first component element and the second component element. Conversely, when one component element is “directly connected” to another component element or is “directly connected to” another component element, it can be understood that there is no third component element between the first component element and the second component element.

[0040] The terms used in the various embodiments of the application are only used to describe the purpose of specific embodiments and are not intended to limit the various embodiments of the application. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. Unless otherwise limited, all terms used here (including technical terms and scientific terms) have the same meaning as the meanings commonly understood by ordinary technicians in the field of the various embodiments of the application. The terms (such as the terms defined in the dictionary generally used) will be interpreted as having the same meaning as the contextual meaning in the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning, unless clearly defined in the various embodiments of the application.

[0041] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with examples and drawings. The illustrative implementation scheme of the present application and its description are only used to explain the present application and are not intended to limit the present application.

[0042] Comparative Example:

[0043] See also Fig. 9 As shown, a conventional staggered double-gate slow-wave structure includes an upper gate portion and a lower gate portion disposed on the upper and lower sides, wherein the upper gate portion and the lower gate portion both form rectangular protrusions at equal intervals along the axial direction to form a periodic waveguide curve, and the periodic waveguide curve of the upper gate portion has a phase difference with the periodic waveguide curve of the lower gate portion.

[0044] See also Fig.10 As shown, the segmented sinusoidal waveguide slow-wave structure includes an upper grid portion and a lower grid portion disposed on the upper and lower sides, each of the upper grid portion and the lower grid portion includes a plurality of segmented sinusoidal waveguides connected in sequence, each segmented sinusoidal waveguide is composed of a complete period of a sinusoidal waveguide and two flat waveguides, the two flat waveguides are respectively disposed at the crest and trough of the sinusoidal waveguide, and the two ends of the flat waveguide are respectively tangent to the sinusoidal waveguides on both sides of the flat waveguide.

[0045] Example 1

[0046] This embodiment aims to overcome the problems of large transmission loss and narrow bandwidth of conventional slow-wave structures, and proposes a new sinusoidal staggered double-gate slow-wave structure to expand bandwidth and reduce transmission loss, thereby increasing the output power in the terahertz band. The implementation method will be described in detail below with reference to the accompanying drawings.

[0047] See also Figure 1-3 As shown, the sinusoidal staggered double-gate slow-wave structure includes an upper gate portion 1 and a lower gate portion 2 respectively disposed on the upper and lower sides, wherein the upper gate portion 1 and the lower gate portion 2 both form sinusoidal protrusions 3 at equal intervals along the axial direction to constitute a periodic waveguide curve, and the periodic waveguide curve of the upper gate portion 1 and the periodic waveguide curve of the lower gate portion 2 have a phase difference.

[0048] Specifically, see Figure 1 As shown, the side of the sinusoidal staggered double-grid slow-wave structure is cut, and the internal structure can be intuitively seen. The sinusoidal staggered double-grid slow-wave structure includes an upper grid portion 1 and a lower grid portion 2, and the upper and lower grid portions are relatively arranged. The relative arrangement here means that the upper grid portion 1 is parallel to the lower grid portion 2, and the edges correspond to each other. The upper grid portion 1 and the lower grid portion 2 extend along the axial direction and form sinusoidal protrusions 3 at equal intervals. The envelope lines of the surfaces of the upper grid portion 1 and the lower grid portion 2 can be regarded as periodic waveguide curves, and the periodic waveguide curve of the upper grid portion 1 and the periodic waveguide curve of the lower grid portion 2 have a phase difference.

[0049] The main part of the sinusoidal staggered double-grid slow-wave structure adopts sinusoidal protrusions 3, which are smooth as a whole, reducing the sudden change points of the field in the slow-wave structure, thereby reducing the loss of electromagnetic waves during transmission. The sinusoidal protrusions of the upper and lower grid parts are staggered, which effectively improves the bandwidth.

[0050] Furthermore, the periodic waveguide curve of the upper gate portion 1 and the periodic waveguide curve of the lower gate portion 2 have a phase difference of half a period.

[0051] The boundary of the sinusoidal protrusion 3 is a half-period sinusoidal curve. A half-period sinusoidal curve is half of a complete sinusoidal curve. The half-period sinusoidal curve is smooth as a whole without mutation points, has low overall transmission loss, and is easy to process.

[0052] For ease of description, see Figure 2-3 As shown, the width of the upper gate portion 1 and the lower gate portion 2 is set to a, and the height is set to b; the single period length of the periodic waveguide curve is set to p; the width of the sinusoidal protrusion 3 is consistent with the width of the upper and lower gate portions, which is a, the height is set to h, and the thickness is set to d (the period of the complete sinusoidal curve is 2d); the distance between two adjacent sinusoidal protrusions is set to L, and the height of the electron injection channel 4 is set to hb;

[0053] Among them, b=2h+hb, p=L+d, hb≤b / 4.

[0054] Furthermore, L=2d, p=3d.

[0055] In specific implementation, the size can be set as follows. Figure 2 The side view shows that the height of the sinusoidal protrusion is h = 0.21 mm, the thickness of the sinusoidal protrusion is d = 0.105 mm, the distance between two adjacent sinusoidal protrusions is L = 2d = 0.21 mm, the height of the electron beam channel is hb = 0.09 mm, and the single period length of the periodic waveguide curve is p = 3d = 0.315 mm; see Figure 3 In the front view, the width of the upper and lower grid parts is a=0.5mm, and the height is b=0.51mm.

[0056] Furthermore, the upper grid portion 1 and the lower grid portion 2 are made of metal, the sinusoidal protrusion 3 has a higher structural strength and a larger power capacity, and is made of metal, which is easier to dissipate heat and is suitable for working in high frequency bands.

[0057] During actual processing, the sinusoidal protrusion 3 can be formed by milling.

[0058] Finally, in order to illustrate the actual effect of the sinusoidal staggered double-grid slow-wave structure provided in this embodiment, microwave simulation software is used to analyze and compare Fig. 9 , Fig.10 The conventional staggered double-gate slow-wave structure and segmented sinusoidal waveguide slow-wave structure shown in the figure provide the following conclusions:

[0059] Figure 4 The comparison of Brillouin diagrams shows that compared with the conventional staggered double-gate slow-wave structure, the bandwidth of the sinusoidal staggered double-gate slow-wave structure increases by about 18 GHz, an increase of about 22%; compared with the segmented sinusoidal waveguide slow-wave structure, the bandwidths of the two are basically the same.

[0060] Figure 5 The dispersion curves are compared. Compared with the conventional staggered double-gate slow-wave structure, the dispersion curve of the sinusoidal staggered double-gate slow-wave structure is flatter under the same size.

[0061] Figure 6 is the S parameter of the sinusoidal staggered double-grid slow-wave structure. The model parameters remain unchanged, and the slow-wave structure contains 80 main periods and 10 transition periods. It is calculated that the effective conductivity of the medium at 340 GHz is 2.3×10 7 It can be seen that within 305GHz-375GHz, S11 is less than -20dB; within 315GHz-400GHz, S21 is greater than -8dB; within 335GHz-385GHz, S21 is greater than -6dB.

[0062] Figure 7 The comparison of S21 parameters. In the range of 320GHz-380GHz, compared with the conventional staggered double-gate slow-wave structure, the S21 parameter of the sinusoidal staggered double-gate slow-wave structure is improved by at least 1.7dB, or at least 19%; compared with the segmented sinusoidal waveguide slow-wave structure, the S21 parameter of the sinusoidal staggered double-gate slow-wave structure is improved by at least 0.5dB, or at least 6.5%.

[0063] Figure 8 The figure shows the comparison of transmission loss. In the range of 320GHz-380GHz, compared with the conventional staggered double-grid slow-wave structure, the transmission loss of the sinusoidal staggered double-grid slow-wave structure is reduced by at least 4.5dB / m, or at least 16%; compared with the segmented sinusoidal waveguide slow-wave structure, the transmission loss of the sinusoidal staggered double-grid slow-wave structure is reduced by at least 3.5dB / m, or at least 13%.

[0064] Therefore, according to the simulation results, the sinusoidal staggered double-gate slow-wave structure provided in this embodiment can be obtained:

[0065] 1. Reduce the mutation points in the field of the slow-wave structure, thereby reducing the loss of electromagnetic waves during transmission;

[0066] 2. The bandwidth has been effectively improved.

[0067] Example 2

[0068] This embodiment is based on the sinusoidal staggered double-gate slow-wave structure in Embodiment 1, and provides a traveling wave tube including the slow-wave structure, which expands the bandwidth and reduces the transmission loss, thereby improving the output power in the terahertz band.

[0069] The traveling wave tube includes: an electron gun, a slow-wave structure, a concentrated attenuator, an energy coupler, a focusing system and a collector, etc. The slow-wave structure is used to exchange energy with the accelerated electron beam generated by the electron gun.

[0070] Among them, the slow-wave structure includes an upper gate portion 1 and a lower gate portion 2 respectively arranged on the upper and lower sides. The upper gate portion 1 and the lower gate portion 2 both form sinusoidal protrusions 3 at equal intervals along the axial direction to form a periodic waveguide curve. The periodic waveguide curve of the upper gate portion has a phase difference with the periodic waveguide curve of the lower gate portion.

[0071] Furthermore, the periodic waveguide curve of the upper gate portion 1 and the periodic waveguide curve of the lower gate portion 2 have a phase difference of half a period.

[0072] Furthermore, the boundary of the sinusoidal protrusion 3 is a half-period sinusoidal curve.

[0073] Further, for ease of description, see Figure 2-3 As shown, the width of the upper gate portion 1 and the lower gate portion 2 is set to a, and the height is set to b; the single-period length of the periodic waveguide curve is set to p; the width of the sinusoidal protrusion 3 is consistent with the width of the upper and lower gate portions, which is a, the height is set to h, and the thickness is set to d (the period of the complete sinusoidal curve is 2d); the spacing between two adjacent sinusoidal protrusions is set to L, and the height of the electron injection channel 4 is set to hb; wherein, b=2h+hb, p=L+d, hb≤b / 4, L=2d, p=3d.

[0074] In specific implementation, the size of the slow-wave structure can be set as follows. Figure 2 The side view shows that the height of the sinusoidal protrusion is h = 0.21 mm, the thickness of the sinusoidal protrusion is d = 0.105 mm, the distance between two adjacent sinusoidal protrusions is L = 2d = 0.21 mm, the height of the electron beam channel is hb = 0.09 mm, and the single period length of the periodic waveguide curve is p = 3d = 0.315 mm; see Figure 3In the front view, the width of the upper and lower grid parts is a=0.5mm, and the height is b=0.51mm.

[0075] Furthermore, the upper gate portion 1 and the lower gate portion 2 are made of metal.

[0076] Furthermore, the sinusoidal protrusion 3 is formed by milling.

[0077] The main part of the slow wave structure used in this embodiment adopts sinusoidal protrusions 3, which are smooth as a whole, reducing the mutation points in the field of the slow wave structure, thereby reducing the loss of electromagnetic waves during transmission. The sinusoidal protrusions of the upper and lower grid parts are staggered, so that the bandwidth is effectively improved.

[0078] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sinusoidal staggered double-gate slow-wave structure, characterized by: The invention comprises an upper gate portion and a lower gate portion respectively disposed on the upper and lower sides, wherein the upper gate portion and the lower gate portion both form sinusoidal protrusions at equal intervals in the axial direction, and a plane structure is formed between two adjacent sinusoidal protrusions to form a periodic waveguide curve, and the periodic waveguide curve of the upper gate portion and the periodic waveguide curve of the lower gate portion have a phase difference; Wherein, the boundary of the sinusoidal protrusion is a half-period sinusoidal curve.

2. The sinusoidal staggered double-gate slow-wave structure according to claim 1, characterized in that: The periodic waveguide curve of the upper gate portion and the periodic waveguide curve of the lower gate portion have a phase difference of half a period.

3. The sinusoidal staggered double-gate slow-wave structure according to claim 1, characterized in that: The width of the upper gate portion and the lower gate portion is a, the height is b, the period of the periodic waveguide curve is p, the width of the sinusoidal protrusion is a, the height is h, the thickness is d, the spacing between two adjacent sinusoidal waveguides is L, and the height of the electron injection channel is hb; Among them, b=2h+hb, p=L+d, hb≤b / 4.

4. The sinusoidal staggered double-gate slow-wave structure according to claim 3, characterized in that: L=2d, p=3d.

5. The sinusoidal staggered double-gate slow-wave structure according to claim 3, characterized in that: a=0.5mm, b=0.51mm, p=0.315mm.

6. The sinusoidal staggered double-gate slow-wave structure according to claim 3, characterized in that: h=0.21mm, d=0.105mm, L=0.21mm, hb=0.09mm.

7. The sinusoidal staggered double-gate slow-wave structure according to claim 1, characterized in that: The upper gate portion and the lower gate portion are made of metal.

8. The sinusoidal staggered double-gate slow-wave structure according to claim 1, characterized in that: The sinusoidal protrusion is formed by milling.

9. A traveling wave tube, characterized in that: It comprises a sinusoidal staggered double-gate slow-wave structure as claimed in any one of claims 1 to 8.

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