CN115954248A - Sine type staggered double-gate slow wave structure - Google Patents

Abstract

The invention discloses a sine type staggered double-gate slow wave structure, relates to the technical field of vacuum electronics, solves the problems of large transmission loss, narrow bandwidth and the like of the conventional slow wave structure, and has the technical scheme that: the grating structure comprises an upper grating part and a lower grating part which are respectively arranged at the upper side and the lower side, wherein the upper grating part and the lower grating part are axially equidistant to form sinusoidal bulges to form a periodic waveguide curve, and the periodic waveguide curve of the upper grating part and the periodic waveguide curve of the lower grating part have phase difference; the abrupt change point of the field in the traditional rectangular protrusion is reduced through the smooth sinusoidal protrusion, so that the loss of electromagnetic waves in the transmission process is reduced, the sinusoidal protrusions of the upper grid part and the lower grid part are arranged in a staggered mode, the bandwidth is higher than that of a traditional staggered double-grid slow-wave structure, and the traveling wave tube slow-wave structure capable of improving the output power is provided for the submillimeter wave band and the terahertz wave band.

Description

Sine type staggered double-gate slow wave structure

Technical Field

The invention relates to the technical field of vacuum electronics, in particular to a sine staggered double-gate slow wave structure.

Background

The terahertz technology is a most concerned hot research direction in the field of electronic science at home and abroad since a new century, and is an interdiscipline influenced by electronics and photonics. Terahertz waves have electromagnetic radiation characteristics completely different from those of microwaves, visible light and the like, and have great application prospects in multiple fields of biomedicine, electronic countermeasure, remote communication, nondestructive testing, astronomy and the like.

In the terahertz frequency band, a vacuum electronic device is a common high-power radiation source. In the existing vacuum electronic device, the traveling wave tube has the advantages of high efficiency, high gain, wide working bandwidth and the like, and is a traditional O-shaped device, and the slow wave structure is a core component of the whole traveling wave tube. With the increase of working frequency, the problems of large transmission loss, narrow bandwidth, strong reflection and the like of the terahertz waveband slow-wave structure become decisive factors for restricting the development of an O-shaped device in the terahertz waveband. Therefore, a novel slow wave structure is urgently needed to be explored at present, the problems of large transmission loss, narrow bandwidth and the like of the traditional slow wave structure are solved, and the development of a terahertz waveband high-power radiation source is promoted.

Disclosure of Invention

The application aims to provide a sine staggered double-gate slow wave structure, which overcomes the problems of large transmission loss, narrow bandwidth and the like of the conventional slow wave structure.

The technical purpose of the application is realized by the following technical scheme: the grating structure comprises an upper grating part and a lower grating part which are respectively arranged at the upper side and the lower side, wherein the upper grating part and the lower grating part are both axially equidistant to form sinusoidal bulges to form a periodic waveguide curve, and the periodic waveguide curve of the upper grating part and the periodic waveguide curve of the lower grating part have phase difference.

By adopting the technical scheme, the abrupt change point of the field in the traditional rectangular protrusion is reduced through the smooth sine protrusion, so that the loss of electromagnetic waves in the transmission process is reduced, the sine protrusions of the upper grid part and the lower grid part are arranged in a staggered mode, the slow wave structure has higher bandwidth compared with the traditional slow wave structure, and the slow wave structure of the traveling wave tube for improving the output power is provided for the submillimeter wave band and the terahertz wave band.

Further, the periodic waveguide curve of the upper gate part and the periodic waveguide curve of the lower gate part have a phase difference of half a period.

Further, the boundary of the sine-shaped bulge is a half-cycle sine curve.

Further, the width of the upper gate part and the height of the lower gate part are a and b, the period of the periodic waveguide curve is p, the width of the sinusoidal projection is a, the height of the sinusoidal projection is h, the thickness of the sinusoidal projection is d, the distance 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.

Further, L =2d, p =3d.

Further, a =0.5mm, b =0.51mm, p =0.315mm.

Further, h =0.21mm, d =0.105mm, l =0.21mm, hb =0.09mm.

Further, the upper gate portion and the lower gate portion are made of metal.

By adopting the technical scheme, the upper grid part and the lower grid part are made of metal, the sine-shaped protrusion structure has higher strength and higher power capacity, and the metal is easier to dissipate heat and is suitable for working in a high-frequency section.

Furthermore, the sine-shaped protrusions are machined and formed in a milling mode.

In another aspect of the present application, a traveling-wave tube is provided, which includes a sine-shaped staggered double-gate slow-wave structure as described above.

By adopting the technical scheme, the traveling wave tube comprises the slow wave structure, so that the bandwidth can be expanded, the transmission loss can be reduced, and the output power of the terahertz wave band can be improved.

Compared with the prior art, the method has the following beneficial effects:

1. the main body part of the sine staggered double-gate slow wave structure is a smooth sine bulge, so that the field discontinuity in the slow wave structure is reduced, the loss of electromagnetic waves in the transmission process is reduced, and the sine bulge is a complete half-cycle sine curve, so that the transmission loss is low and the processing is easy;

2. compared with a conventional staggered double-gate slow-wave structure, the sinusoidal staggered double-gate slow-wave structure has the advantages that the bandwidth is effectively improved;

3. the sine staggered double-gate slow wave structure is an all-metal slow wave structure, the sine convex structure is higher in strength, higher in power capacity, easier to dissipate heat and suitable for working in a high-frequency band.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a schematic diagram of a sinusoidal staggered double gate slow wave structure;

FIG. 2 is a side view of a sinusoidal staggered double gate slow wave structure;

FIG. 3 is a front view of a sinusoidal staggered double gate slow wave structure;

FIG. 4 is a Brillouin diagram comparing the sine type staggered double-gate slow-wave structure with the conventional staggered double-gate slow-wave structure and the segmented sine waveguide slow-wave structure;

FIG. 5 is a comparison of dispersion curves of a sinusoidal staggered double-gate slow-wave structure and a conventional staggered double-gate slow-wave structure and a segmented sinusoidal waveguide slow-wave structure;

FIG. 6 is the high frequency transmission characteristics of a sinusoidal staggered double gate slow wave structure;

FIG. 7 is a comparison of S21 curves of a sine-type staggered double-gate slow-wave structure and a conventional staggered double-gate slow-wave structure and a segmented sine-waveguide slow-wave structure;

FIG. 8 is a comparison of transmission loss of a sinusoidal staggered double-gate slow-wave structure and a conventional staggered double-gate slow-wave structure and a segmented sinusoidal waveguide slow-wave structure;

FIG. 9 is a schematic diagram of a conventional staggered double gate slow wave structure;

FIG. 10 is a schematic diagram of a segmented sinusoidal waveguide slow wave structure;

reference numbers and corresponding part names in the drawings:

1. an upper gate portion; 2. a lower gate portion; 3. a sinusoidal protrusion; 4. and an electron beam channel.

Detailed Description

Hereinafter, the terms "includes" or "may include" used in various embodiments of the present application indicate the presence of the claimed function, operation, or element, and do not limit the addition of one or more functions, operations, or elements. Furthermore, as used in various embodiments of the present application, the terms "comprising," "having," and their derivatives, are intended to be inclusive and mean only that a particular feature, number, step, operation, element, component, or combination of the foregoing is meant, and should not be construed as first excluding the presence of, or adding to, one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing.

In various embodiments of the present application, the expression "or" at least one of B or/and C "includes any or all combinations of the words listed simultaneously. 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.

Expressions (such as "first", "second", and the like) used in various embodiments of the present application may modify various constituent elements in the various embodiments, but may not limit the respective constituent elements. For example, the above description does not limit the order and/or importance of the elements described. The foregoing description is for the purpose of distinguishing one element from another. For example, the first user device and the second user device indicate different user devices, although both are user devices. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of various embodiments of the present application.

It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.

It should be noted that: if it is described that one constituent element is "connected" to or "connected" with another constituent element, the first constituent element may be directly connected to the second constituent element, and the third constituent element may be "connected" between the first constituent element and the second constituent element. In contrast, when one constituent element is "directly connected" to or with another constituent element, it is understood that there is no third constituent element between the first constituent element and the second constituent element.

The terminology used in the various embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the various embodiments of the present application. As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of the present application belong. The terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning that is consistent with their contextual meaning in the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein in various embodiments.

To make the purpose, technical solution and advantages of the present application more apparent, the present application is further described in detail below with reference to examples and drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present application and are not used as limitations of the present application.

Comparative example:

referring to fig. 9, the conventional staggered double-gate slow-wave structure: the grating structure comprises an upper grating part and a lower grating part which are respectively arranged at the upper side and the lower side, wherein the upper grating part and the lower grating part are axially and equidistantly formed into rectangular bulges to form a periodic waveguide curve, and the periodic waveguide curve of the upper grating part and the periodic waveguide curve of the lower grating part have phase difference.

Referring to fig. 10, the segmented sine waveguide slow wave structure: the grating structure comprises an upper grating part and a lower grating part which are respectively arranged at the upper side and the lower side, wherein the upper grating part and the lower grating part respectively comprise a plurality of segmented sinusoidal waveguides which are sequentially connected, each segmented sinusoidal waveguide consists of a sinusoidal waveguide with a complete cycle and two flat waveguides, the two flat waveguides are respectively arranged at the peak top and the trough concave of the sinusoidal waveguide, and the two ends of each flat waveguide are respectively tangent to the sinusoidal waveguides at the two sides of the flat waveguides.

Example 1

The embodiment aims to solve the problems of large transmission loss, narrow bandwidth and the like of a conventional slow wave structure, and provides a novel sine staggered double-gate slow wave structure to expand the bandwidth and reduce the transmission loss, so that the output power of a terahertz wave band is improved. The embodiments will be described in detail below with reference to the accompanying drawings.

Referring to fig. 1-3, the sine-shaped staggered double-gate slow-wave structure includes an upper gate portion 1 and a lower gate portion 2 which are respectively disposed at the upper side and the lower side, the upper gate portion 1 and the lower gate portion 2 are equally spaced along the axial direction to form sine-shaped protrusions 3, so as to form 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.

Specifically, referring to fig. 1, the side surface of the sine-shaped staggered double-gate slow-wave structure is cut, so that the internal structure can be seen visually, and the sine-shaped staggered double-gate slow-wave structure includes an upper gate portion 1 and a lower gate portion 2, and the upper gate portion and the lower gate portion are arranged oppositely, where the relative arrangement means that the upper gate portion 1 is parallel to the lower gate portion 2, and the sides correspond to the sides. The upper grid part 1 and the lower grid part 2 extend along the axial direction and are equally spaced into sine-shaped protrusions 3, the envelope curves of the surfaces of the upper grid part 1 and the lower grid part 2 can be regarded as periodic waveguide curves, and the periodic waveguide curves of the upper grid part 1 and the periodic waveguide curves of the lower grid part 2 have phase differences.

The main body part of the sine staggered double-gate slow wave structure adopts the sine bulge 3, so that the whole structure is smooth, and the abrupt change points of the field in the slow wave structure are reduced, thereby reducing the loss of electromagnetic waves in the transmission process. And the sine-shaped bulges of the upper grid part and the lower grid part are arranged in a staggered manner, so that the bandwidth is effectively improved.

Further, the periodic waveguide curve of the upper gate part 1 and the periodic waveguide curve of the lower gate part 2 have a phase difference of half a period.

The sinusoidal bumps 3 are bounded by half-cycle sinusoids. Half cycle sinusoidal curve is half of complete sinusoidal curve, adopts half cycle sinusoidal type curve, and whole smoothness does not have the abrupt point, and whole transmission loss is low, and easily processing.

For convenience of description, referring to fig. 2 to 3, the width of the upper gate 1 and the lower gate 2 is set as a, and the height is set as b; setting the length of a single period of the periodic waveguide curve as p; the width of the sine-shaped bulge 3 is consistent with the width of the upper grid part and the lower grid part, the height is set as h, and the thickness is set as d (the period of a complete sine curve is 2 d); the distance between two adjacent sinusoidal bumps is set as L, and the height of the electron beam channel 4 is set as hb;

wherein b =2h + hb, p = L + d, hb ≦ b/4.

Further, L =2d, p =3d.

In particular, the dimensions may be set as follows. Referring to the side view of fig. 2, the height h =0.21mm of the sinusoidal bumps, the thickness d =0.105mm of the sinusoidal bumps, the distance L =2d =0.21mm between two adjacent sinusoidal bumps, the electron beam channel height hb =0.09mm, and the single period length p =3d =0.315mm of the periodic waveguide curve; referring to the front view of fig. 3, the upper and lower gate portions have a width a =0.5mm and a height b =0.51mm.

Further, the upper grid part 1 and the lower grid part 2 are made of metal, the sine-shaped protrusions 3 are higher in structural strength, have higher power capacity, are made of metal, are easier to dissipate heat and are suitable for working in a high-frequency range.

During actual processing, the sinusoidal protrusions 3 can be formed by milling.

Finally, in order to illustrate the practical effect of the sine-type staggered double-gate slow-wave structure provided by the embodiment, a microwave simulation software is used for analysis, and compared with the conventional staggered double-gate slow-wave structure and the segmented sine-waveguide slow-wave structure shown in fig. 9 and 10, the following conclusion is obtained:

fig. 4 is a comparison of brillouin plots. Compared with a conventional staggered double-gate slow-wave structure, the bandwidth of the sine staggered double-gate slow-wave structure is increased by about 18GHz, and is improved by about 22%; compared with a segmented sine waveguide slow wave structure, the bandwidth of the two structures is basically the same.

Fig. 5 is a comparison of dispersion curves. Compared with the conventional staggered double-gate slow-wave structure, the dispersion curve of the sine staggered double-gate slow-wave structure is flatter under the same size.

Fig. 6 is an S parameter of a sine-type staggered double-gate slow-wave structure. The model parameters are unchanged, and the slow wave structure comprises 80 main periods and 10 transition periods. The effective conductivity of the medium at 340GHz was calculated to be 2.3X 10 ⁷ . It can be seen that within 305GHz-375GHz, S11 is less than-20 dB; within 315GHz-400GHz, S21 is larger than-8 dB; and S21 is greater than-6 dB within 335GHz-385 GHz.

Fig. 7 is a comparison of the S21 parameter. In 320GHz-380GHz, compared with a conventional staggered double-gate slow-wave structure, the S21 parameter of the sine staggered double-gate slow-wave structure is improved by at least 1.7dB and is improved by at least 19%; compared with a segmented sine waveguide slow wave structure, the S21 parameter of the sine staggered double-gate slow wave structure is improved by at least 0.5dB and is improved by at least 6.5%.

Fig. 8 shows a comparison of transmission losses. In 320GHz-380GHz, compared with a conventional staggered double-gate slow-wave structure, the transmission loss of the sine staggered double-gate slow-wave structure is reduced by at least 4.5dB/m and is reduced by at least 16%; compared with a segmented sine waveguide slow wave structure, the transmission loss of the sine staggered double-gate slow wave structure is reduced by at least 3.5dB/m and is reduced by at least 13%.

Therefore, according to the simulation result, the sinusoidal staggered double-gate slow-wave structure provided by the embodiment can be obtained:

1. the abrupt change points of the field in the slow wave structure are reduced, so that the loss of electromagnetic waves in the transmission process is reduced;

2. the bandwidth is effectively improved.

Example 2

The embodiment provides a traveling wave tube including the slow wave structure based on the sinusoidal staggered double-gate slow wave structure in embodiment 1, and the traveling wave tube expands the bandwidth, reduces the transmission loss, and improves the output power of the terahertz wave band.

The traveling wave tube includes: electron gun, slow wave structure, centralized attenuator, energy coupler, focusing system and collector; the slow wave structure is used for exchanging energy with the accelerated electron beam generated by the electron gun.

The slow wave structure comprises an upper grid part 1 and a lower grid part 2 which are respectively arranged at the upper side and the lower side, the upper grid part 1 and the lower grid part 2 are axially equidistant to form sinusoidal bulges 3 to form a periodic waveguide curve, and the periodic waveguide curve of the upper grid part and the periodic waveguide curve of the lower grid part have phase difference.

Further, the periodic waveguide curve of the upper gate part 1 and the periodic waveguide curve of the lower gate part 2 have a phase difference of half a period.

Further, the sinusoidal protrusions 3 are bounded by half-cycle sinusoids.

Further, for convenience of description, referring to fig. 2 to 3, the width of the upper gate 1 and the lower gate 2 is set as a, and the height is set as b; the single period length of the periodic waveguide curve is set as p; the width of the sine-shaped bulge 3 is consistent with the width of the upper grid part and the lower grid part, the height is set as h, and the thickness is set as d (the period of a complete sine curve is 2 d); the distance between two adjacent sinusoidal bumps is set as L, and the height of the electron beam channel 4 is set as hb; wherein, b =2h + hb, p = L + d, hb ≦ b/4, L =2d, p =3d.

In particular, the size of the slow wave structure may be set as follows. Referring to the side view of fig. 2, the height h =0.21mm of the sinusoidal protrusions, the thickness d =0.105mm of the sinusoidal protrusions, the distance L =2d =0.21mm between two adjacent sinusoidal protrusions, the electron beam channel height hb =0.09mm, and the single period length p =3d =0.315mm of the periodic waveguide curve; referring to the front view of fig. 3, the upper and lower gate portions have a width a =0.5mm and a height b =0.51mm.

Further, the upper gate portion 1 and the lower gate portion 2 are made of metal.

Further, the sine-shaped protrusions 3 are machined and formed in a milling mode.

The main body part of the slow wave structure adopted by the embodiment adopts the sine-shaped bulge 3, so that the whole slow wave structure is smooth, and the abrupt change points of the field in the slow wave structure are reduced, thereby reducing the loss of electromagnetic waves in the transmission process. And the sine-shaped bulges of the upper grid part and the lower grid part are arranged in a staggered manner, so that the bandwidth is effectively improved.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (10)

1. A sine type staggered double-gate slow wave structure is characterized in that: the grating structure comprises an upper grating part and a lower grating part which are respectively arranged at the upper side and the lower side, wherein the upper grating part and the lower grating part are both axially equidistant to form sinusoidal bulges to form a periodic waveguide curve, and the periodic waveguide curve of the upper grating part and the periodic waveguide curve of the lower grating part have phase difference.

2. The sine-shaped staggered double-gate slow wave structure according to claim 1, wherein: the periodic waveguide curve of the upper grid part and the periodic waveguide curve of the lower grid part have a phase difference of half period.

3. The sine-shaped staggered double-gate slow wave structure according to claim 2, wherein: the boundary of the sine-shaped bulge is a half-period sine curve.

4. The sinusoidal staggered double gate slow wave structure of claim 1, wherein: the width of the upper gate part and the height of the lower gate part are a and b, the period of the periodic waveguide curve is p, the width of the sinusoidal projection is a, the height of the sinusoidal projection is h, the thickness of the sinusoidal projection is d, the distance 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.

5. The sinusoidal staggered double gate slow wave structure of claim 4, wherein: l =2d, p =3d.

6. The sinusoidal staggered double gate slow wave structure of claim 4, wherein: a =0.5mm, b =0.51mm, p =0.315mm.

7. The sinusoidal staggered double gate slow wave structure of claim 4, wherein: h =0.21mm, d =0.105mm, l =0.21mm, hb =0.09mm.

8. The sine-shaped staggered double-gate slow wave structure according to claim 1, wherein: the upper gate portion and the lower gate portion are made of metal.

9. The sine-shaped staggered double-gate slow wave structure according to claim 1, wherein: the sine-shaped protrusions are machined and formed in a milling mode.

10. A traveling wave tube, characterized by: comprising a sinusoidal staggered double gate slow wave structure according to any of claims 1 to 9.

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