CN113594008A

CN113594008A - Extended interaction klystron

Info

Publication number: CN113594008A
Application number: CN202111030610.2A
Authority: CN
Inventors: 张煦; 张瑞; 王勇; 廖云峰; 杨修东; 耿志辉
Original assignee: Aerospace Information Research Institute of CAS
Current assignee: Aerospace Information Research Institute of CAS
Priority date: 2021-09-03
Filing date: 2021-09-03
Publication date: 2021-11-02

Abstract

The invention relates to an extended interaction klystron, comprising: a body having a cylindrical outer profile, formed within the body: a first resonant cavity, a second resonant cavity, and at least one intermediate resonant cavity located between the first resonant cavity and the second resonant cavity, the first resonant cavity, the second resonant cavity, and the intermediate resonant cavity each comprising: a plurality of resonance parts distributed at intervals in a circumferential direction in the body; and a plurality of grating portions arranged to be alternately provided with the plurality of resonance portions in a circumferential direction within the body, each of the grating portions communicating with adjacent two of the resonance portions; and a plurality of electron beam channels, each extending in the axial direction through the body and communicating with grating portions of the first, second, and intermediate resonant cavities that are aligned in the axial direction.

Description

Extended interaction klystron

Technical Field

The invention belongs to the technical field of high-power microwaves in vacuum electronic devices, and particularly relates to an expanded interaction klystron.

Background

The klystron as a power amplifier has the advantages of high power, high efficiency, high stability and long service life, and has important application in the aspects of high-power millimeter wave radar, long-distance high-speed wireless communication, millimeter wave electronic countermeasure, national safety, controlled nuclear fusion and industrial application.

In recent years, with the development of large scientific experimental devices and microwave electronic systems, higher requirements are put on the performance of millimeter wave devices. The Extended Interaction Klystron (EIK) combines the advantages of a coupled cavity traveling wave tube and the advantages of a traditional klystron, and is expected to realize high output power and high efficiency in a high-frequency band. The extended interaction technology uses a multi-gap resonance portion as an interaction circuit, and has the characteristics of high characteristic impedance and high unit length gain. Meanwhile, the short interaction length is suitable for permanent magnet focusing, and the risk of interception of the drift tube on electron beams can be effectively reduced. However, in order to achieve efficient beam-wave interaction, the diameter of the electron beam channel needs to be much smaller than the operating wavelength, so that the power level of the conventional single-beam EIK drops sharply in the high frequency band.

Ribbon-beam technology and multi-beam technology have been used for extended interaction devices with trapezoidal structures because they can greatly increase output power while maintaining reasonable current density and operating voltage. Common EIK chooses trapezoidal resonance portion of work in the fundamental mode as the interaction structure for use, however along with the promotion of frequency, the size of cavity can reduce rapidly, and strong electric field concentrates on in the small-size cavity this moment, can increase the risk of voltage breakdown. Meanwhile, due to the limitation of the cathode emission current density, the traditional EIK trapezoidal cavity is difficult to meet the requirement of a high-power electronic optical system on the cross section size of the cavity.

Disclosure of Invention

In view of the prior art problems, the present invention provides an extended interaction klystron for at least partially solving the above technical problems.

An embodiment of the present invention provides an extended interaction klystron, including: a body having a cylindrical outer profile, formed within the body: a first resonant cavity, a second resonant cavity, and at least one intermediate resonant cavity located between the first resonant cavity and the second resonant cavity, the first resonant cavity, the second resonant cavity, and the intermediate resonant cavity each comprising: a plurality of resonance parts distributed at intervals in a circumferential direction in the body; and a plurality of grating portions arranged to be alternately provided in the circumferential direction within the body with the plurality of resonance portions, each of the grating portions communicating with two adjacent resonance portions, wherein at least one grating portion of the first resonance cavity communicates with the input waveguide, at least one grating portion of the second resonance cavity communicates with the output waveguide, and a plurality of electron beam channels each extending through the body in the axial direction and communicating with grating portions of the first, second, and intermediate resonance cavities aligned in the axial direction.

According to an embodiment of the present disclosure, each of the grating portions includes a plurality of fan-shaped resonant gaps spaced in the axial direction and extending in a radial direction.

According to an embodiment of the present disclosure, the input waveguide includes: the annular input cavity extends into the body from a first end of the body in the axial direction and is communicated with one of the fan-shaped resonant gaps of the grating part of the first resonant cavity; the output waveguide includes: and the annular output cavity extends from the second end of the body in the axial direction to the inside of the body and is communicated with one of the fan-shaped resonant gaps of the grating part of the second resonant cavity.

According to an embodiment of the present disclosure, the body is further formed with: an input waveguide transition portion formed as a chamber integrally extending from an inner side in an axial direction of the annular input cavity toward an inner side in a radial direction of a sector resonance gap of the first resonance cavity, the input waveguide transition portion communicating with one sector resonance gap of the first resonance cavity; and an output waveguide transition portion formed as a cavity extending integrally from an inner side in an axial direction of the annular output cavity toward an inner side in a radial direction of a sector resonance gap of the second resonance cavity, the output waveguide transition portion communicating with one sector resonance gap of the second resonance cavity.

According to an embodiment of the present disclosure, the input waveguide transformation portion communicates with the sector resonance gap through a sector input coupling hole; the output waveguide transformation part is communicated with the fan-shaped resonant gap through a fan-shaped output coupling hole.

According to the embodiment of the present disclosure, a center-to-center distance between two adjacent sector resonances in the grating portion is taken as one period length of the grating portion; the width of each fan-shaped resonant gap in the grating part is the same, and the width of each fan-shaped resonant gap is 1/3-1/2 times of the period length of the fan-shaped resonant gap.

According to an embodiment of the present disclosure, a width of the resonance portion is N times a period length of the fan-shaped resonance gap, where N is characterized by a number of the fan-shaped resonance gaps in one of the grating portions communicating with the resonance portion.

According to the embodiment of the disclosure, the inner diameter of the electron beam channel is 1/6-1/4 times of the operating wavelength of the klystron.

According to an embodiment of the present disclosure, each of the first resonant cavity, the second resonant cavity, and the intermediate resonant cavity includes: 5 multiple resonance parts and 5 grating parts; wherein each grating portion of the first resonant cavity comprises 3-5 fan-shaped resonant gaps; wherein each grating portion of the intermediate resonant cavity comprises 3-5 fan-shaped resonant gaps; wherein each of the grating portions of the second resonant cavity includes 5-7 fan-shaped resonant gaps. According to an embodiment of the present disclosure, the curvature of the resonance portion of each of the first, second and intermediate resonant cavities is 28-32 °; the radian of each of the fan-shaped resonant gaps of the grating portion of each of the first, second and intermediate resonant cavities is 44-40 °; the geometric centers of the fan-shaped resonant gap and each of the resonant portions are located on the same concentric circle.

According to the embodiment of the invention, the klystron with the extended interaction is provided, the klystron is matched by the grating parts and the resonance parts which are axially arranged at intervals and is not restricted by a size common degree effect, still has a larger interaction section at a higher working frequency band, has good high-order mode selectivity, can further enhance a working mode electric field near the drift tube, and can realize high-power output more stably and efficiently at a millimeter wave frequency band.

Drawings

FIG. 1 illustrates a schematic structural view of a klystron of an exemplary embodiment of the present disclosure;

FIG. 2 schematically illustrates a cross-sectional view of the klystron of FIG. 1 in an axial direction;

FIG. 2a is a cross-sectional view taken along the line A-A in FIG. 2 in the radial direction;

FIG. 2b is a schematic perspective view of the input waveguide transition and sector grating gap junction shown in FIG. 2 a;

FIG. 2c is a cross-sectional view taken along the line B-B in FIG. 2;

FIG. 2d is a cross-sectional view taken along the line C-C of FIG. 2;

FIG. 2e is an enlarged schematic view of section D shown in FIG. 2;

FIG. 3 illustrates a graph of the peak output power of the amplified signal of the klystron of an exemplary embodiment of the present disclosure;

FIG. 4 illustrates an output signal spectrum of a klystron of an exemplary embodiment of the present disclosure; and

fig. 5 shows a schematic diagram of an electric field distribution of a klystron of an exemplary embodiment of the present disclosure.

Detailed Description

In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure.

The terms "comprises," "comprising," and the like, as used herein, specify the presence of stated features, steps, operations, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components. All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined. It is noted that the terms used herein should be interpreted as having a meaning that is consistent with the context of this specification and should not be interpreted in an idealized or overly formal sense.

Where a convention analogous to "at least one of A, B and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B and C" would include but not be limited to systems that have a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B, C together, etc.). Where a convention analogous to "A, B or at least one of C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B or C" would include but not be limited to systems that have a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B, C together, etc.).

FIG. 1 illustrates a schematic structural view of a klystron of an exemplary embodiment of the present disclosure; FIG. 2

Fig. 2 schematically shows a sectional view of the klystron of fig. 1 in an axial direction.

According to a general inventive concept of the present disclosure, as shown in fig. 1 and 2, there is provided an extended interaction klystron, comprising: a body (1), said body (1) having a cylindrical outer profile, formed inside said body (1); a first resonant cavity, a second resonant cavity, and at least one intermediate resonant cavity between the first resonant cavity and the second resonant cavity, which are coaxially arranged in an axial direction of the body 1; and a plurality of electron beam channels 2.

Further, each of the first resonant cavity, the second resonant cavity, and the intermediate resonant cavity includes: a plurality of resonance parts 6 distributed at intervals in the circumferential direction in the main body 1; and a plurality of grating portions 4 arranged to be alternately provided with a plurality of the resonance portions 6 in the circumferential direction inside the body 1. Each of the grating portions 4 is communicated with two adjacent resonant portions 6, wherein at least one grating portion 4 of the first resonant cavity is communicated with the input waveguide, and at least one grating portion 4 of the second resonant cavity is communicated with the output waveguide. Each electron beam channel 2 of the plurality of electron beam channels 2 extends in the axial direction through the body 1 and communicates with the grating portions 4 of the first resonant cavity, the second resonant cavity, and the intermediate resonant cavity, which are aligned in the axial direction.

In an exemplary embodiment, the resonance section 6 and the grating section 4 are each formed in a substantially fan-shaped structure.

In an exemplary embodiment, each of the above-described grating portions 4 includes a plurality of substantially fan-shaped resonance gaps 41 spaced in the above-described axial direction and extending in the radial direction.

FIG. 2a is a cross-sectional view taken along the line A-A in FIG. 2 in the radial direction; FIG. 2b is a schematic diagram of the input waveguide transition and sector grating gap junction shown in FIG. 2 a; FIG. 2c is a cross-sectional view taken along the line B-B in FIG. 2; FIG. 2d is a cross-sectional view taken along the line C-C of FIG. 2; fig. 2e is an enlarged schematic view of the portion D shown in fig. 2.

In an exemplary embodiment, as shown in fig. 2a, the input waveguide includes an annular input cavity 30 formed around the axis of the body 1, the annular input cavity 30 extends from a first end of the body 1 in the axial direction into the body 1 and communicates with one of the fan-shaped resonant gaps 41 of the grating portion 4 of the first resonant cavity to input the initial waveguide signal.

In an exemplary embodiment, the input waveguide communicates with a sector-shaped resonant gap 41 located at or adjacent to the central portion in at least one grating portion of the plurality of grating portions 4 of the first resonant cavity.

In one exemplary embodiment, as shown in fig. 2d, the output waveguide comprises: and an annular output cavity 50 formed around the axis of the body 1, wherein the annular output cavity 50 extends from a second end of the body 1 in the axial direction into the body 1 and is communicated with one of the fan-shaped resonant gaps 41 of the grating portion 4 of the second resonant cavity to output a high-frequency waveguide, such as a terahertz wave.

In an exemplary embodiment, the output waveguide communicates with the sector-shaped resonant gap 41 located in the middle or adjacent to the middle in at least one of the plurality of grating sections 4 of the second resonant cavity.

In an alternative embodiment, the input waveguide communicates with a sector-shaped resonant gap 41 of a grating portion 4 of the first resonant cavity in the radial direction to input the initial waveguide signal; the output waveguide communicates with one of the fan-shaped resonance gaps 41 of one grating section 4 of the above-described second resonance cavity in the radial direction to output a high-frequency waveguide such as a terahertz wave. That is, both the input waveguide and the output waveguide are provided independently of the body 1.

In an exemplary embodiment, as shown in fig. 2a and 2b, the body is further formed with an input waveguide transformation portion 32, the input waveguide transformation portion 32 is formed as a cavity integrally extending from an inner side of the annular input cavity 30 in the axial direction toward an inner side of the first resonator in the radial direction of the sector resonance gap 41, and the input waveguide transformation portion 32 communicates with one of the sector resonance gaps 41 of the first resonator.

As shown in fig. 2d, the main body further includes an output waveguide transforming part 52, the output waveguide transforming part 52 is a cavity integrally extending from the inner side of the annular output cavity 50 in the axial direction to the inner side of the second cavity in the radial direction of the sector resonance gap 41, and the output waveguide transforming part 52 communicates with one of the sector resonance gaps 41 of the second cavity. It is understood that the input waveguide transition part 32 and the output waveguide transition part 52 have substantially the same connection structure with the fan-shaped resonance gap 41.

In an exemplary embodiment, the input waveguide transformation part 32 and the sector resonance gap 41 communicate through a sector input coupling hole 31; similarly, the output waveguide transformation part 52 communicates with the sector resonance gap 41 through a sector output coupling hole 51.

In an exemplary embodiment, as shown in fig. 2e, the center-to-center distance a between two adjacent sector resonances in the grating portion 4 is taken as one period length of the grating portion 4.

For example, the width b of each of the fan-shaped resonant gaps 41 in the grating portion 4 is the same, and the width b of each of the fan-shaped resonant gaps 41 is 1/3 to 1/2 times the period length of the fan-shaped resonant gap 41. The width c of the resonance part 6 is N times the period length of the fan-shaped resonance gap 41, where N is represented by the number of the fan-shaped resonance gaps 41 in one of the grating parts 4 communicating with the resonance part 6.

In an exemplary embodiment, the electron beam passage 2 has an inner diameter of 1/6-1/4 times the operating wavelength of the klystron described above.

In an exemplary embodiment, as shown in fig. 2 a-2 e, each of the first resonant cavity, the second resonant cavity, and the intermediate resonant cavity includes: 5

multiple resonance sections

6 and 5 grating sections 4; each of the grating portions 4 of the first cavity includes 3 to 5 fan-shaped resonant gaps 41; each of the grating portions 4 of the intermediate cavity includes 3 to 5 fan-shaped resonant gaps 41; each of said grating portions 4 of said second cavity comprises 5-7 fan-shaped resonant gaps 41. Those skilled in the art will appreciate that the number of intermediate resonant cavities, and the number of resonant gaps in each interstitial cavity, respectively, may be set as desired.

In an exemplary embodiment, FIG. 2c is a cross-sectional view B-B of FIG. 2, and in an exemplary embodiment: the radian β of the resonance part 6 of each of the above-mentioned first resonance cavity, second resonance cavity and intermediate resonance cavity is 28-32 °; the radian of each of said fan-shaped resonance gaps of said grating portion 4 of each of said first, second and intermediate resonance cavities is 44 to 40 °; the geometric centers of each of the fan-shaped resonance gap 41 and the resonance part 6 are located on the same concentric circle.

In an exemplary embodiment, as shown in fig. 2, includes: the electron beam generating device comprises a body 1, a first resonant cavity, a second resonant cavity, two intermediate resonant cavities and a plurality of electron beam channels 2, wherein the first resonant cavity, the second resonant cavity and the two intermediate resonant cavities are coaxially arranged in the axial direction of the body 1, and each electron beam channel 2 penetrates through the body 1 to extend in the axial direction and is communicated with a grating part 4 aligned in the axial direction in the first resonant cavity, the second resonant cavity and the two intermediate resonant cavities. The 4 resonant cavities all work in a TM51-2 pi mode.

In detail, the first resonant cavity includes 5

resonant sections

6, 5 grating sections 4, and a ring-shaped input cavity 30. The parameters of the resonance part 6 are as follows: the inner diameter was 2.8 mm, the outer diameter was 5.6 mm, the arc β was 30 °, and the width c was 2.58 mm. Each grating portion 4 includes 3 fan-shaped resonant gaps 41 therein.

In an exemplary embodiment, the parameters of the fan-shaped resonant gap 41 are as follows: an inner diameter of 3.3 mm, an outer diameter of 5.1 mm, a radian α of 42 °, a width b of 0.38 mm, and a cycle length a of 0.86 mm. The parameters of the annular input chamber 30 are as follows: the inner diameter of the inner ring is 1 mm, the inner diameter of the outer ring is 1.35 mm, the axial length is 5 mm, and the inner ring is communicated with a fan-shaped resonance gap 41 in the middle through an input waveguide transformation part 32, and the communication position forms a fan-shaped input coupling hole 31. The inner diameter of the inner ring of the input waveguide transformation part 32 is 1 mm, the inner diameter of the outer ring is 2.5 mm, and the width is 0.38 mm; wherein, the inner diameter of the fan-shaped input coupling hole 31 is 2.5 mm, the outer diameter is 3.3 mm, the radian is 28 degrees, and the width is 0.38 mm.

In the above description of the relevant widths involved in the resonant section, the grating section and the annular input cavity, the widths are all characterized as lengths in relation to the axial direction of the body 1.

In detail, the second resonant cavity includes 5

resonant sections

6, 5 grating sections 4, and a ring-shaped output cavity 50. The parameters of the resonance part 6 are as follows: the inner diameter was 2.85 mm, the outer diameter was 5.5 mm, the radian β was 30 °, and the width c was 4.2 mm. Each grating portion 4 includes 5 fan-shaped resonant gaps 41 therein. The parameters of the fan-shaped resonant gap 41 are as follows: an inner diameter of 3.3 mm, an outer diameter of 5.1 mm, a radian α of 42 °, a width b of 0.38 mm, and a cycle length a of 0.86 mm.

In an exemplary embodiment, the parameters of the annular output chamber 50 are as follows: the inner diameter of the inner ring is 1.1 mm, the inner diameter of the outer ring is 1.4 mm, the axial length is 6 mm, the inner ring is communicated with the adjacent fan-shaped resonant gap 41 positioned in the middle through the output waveguide transformation part 52, and the communicated position forms a fan-shaped output coupling hole 52; wherein, the inner diameter of the inner ring of the output waveguide transformation part 52 is 1.1 mm, the inner diameter of the outer ring is 2.6 mm, and the width is 0.38 mm; wherein, the inner diameter of the fan-shaped output coupling hole 51 is 2.6 mm, the outer diameter is 3.3 mm, the radian is 28 degrees, and the width is 0.38 mm.

In the above description of the relevant widths involved in the resonant section, the grating section and the annular input cavity, the widths are all characterized as lengths in relation to the axial direction of the body 1. In detail, the intermediate cavity includes 3 resonance sections 6 and 3 grating sections 4. The parameters of the resonance part 6 are as follows: the inner diameter was 2.8 mm, the outer diameter was 5.6 mm, the arc β was 30 °, and the width c was 2.58 mm. Each grating portion 4 includes 3 fan-shaped resonant gaps 41 therein. The parameters of the fan-shaped resonant gap 41 are as follows: an inner diameter of 3.3 mm, an outer diameter of 5.1 mm, a radian α of 42 °, a width b of 0.38 mm, and a cycle length a of 0.86 mm.

In detail, the number of the electron beam channels 2 is 5, which is the same as the number of the grating parts 4 in the same resonant cavity. The inner diameter of each electron beam channel 2 is 0.6 mm; the length of the electron beam channel 2 between the first resonant cavity and the adjacent middle resonant cavity is 2.2 mm; the length of the electron beam channel 2 between the two middle resonant cavities is 2.2 mm; the electron beam passage 2 between the second resonator and the adjacent intermediate resonator is 2.1 mm.

Each of the electron beam channels 2 is provided with an electron generating device at an end (left end in fig. 2) of the first resonant cavity 7, the electron generating device including: a cathode for generating electrons, a control electrode and an anode, the control electrode and the anode cooperating to focus the electrons generated by the cathode into an electron beam suitable for injection into the electron beam channel; each electron beam channel 2 is provided with a collector at an end (right end in fig. 2) of the second resonant cavity, and the collector is used for receiving the electron beam from the electron beam channel.

According to the parameters disclosed in the examples of the present disclosure, when the voltage of the electron beam is 25KV, the current of the electron beam is 7A (5 × 1.4A), the magnetic induction intensity for focusing the electron beam is 0.85T, and the input signal is 100mW, the peak output power of the amplifier is 30.1 kW.

Fig. 3 shows a graph of the peak output power of the amplified signal of the klystron of an exemplary embodiment of the present disclosure. As shown in fig. 3, the corresponding electronic efficiency and gain are 17.2% and 54.8dB, respectively.

Fig. 4 shows a graph of the output signal spectrum of a klystron of an exemplary embodiment of the present disclosure. As shown in fig. 4, the output signal is fourier-transformed to obtain a signal spectrogram, which has pure frequency spectrum without clutter and frequency of 94.4 GHz.

Fig. 5 shows a schematic diagram of an electric field distribution of a klystron of an exemplary embodiment of the present disclosure. As shown in FIG. 5, in order to expand the axial electric field distribution of the interaction klystron during operation, each cavity stably operates in TM51-2 pi mode, and the electric field intensity gradually increases from the input cavity C1 to the output cavity C4. Therefore, the coaxial high-order mode extended interaction klystron has the advantages that the interaction structure can stably and efficiently carry out the injection-wave interaction with five electron beams which are uniformly distributed in an angular direction.

According to the embodiment of the disclosure, electrons generated by a cathode in an external electron generating device are converged into a direct current electron beam through a control electrode and an anode, the direct current electron beam enters a first resonant cavity through an electron beam channel, meanwhile, a seed signal enters the first resonant cavity through an annular input cavity, and the direct current electron beam is preliminarily modulated in the first resonant cavity to form certain velocity clustering. The dc electron beam is then continuously modulated through the intermediate resonators and the drift region between adjacent resonators gradually converts the velocity modulation into a density modulation, forming a cluster. And finally, the clustered beam clusters and the gap electric field in the second resonant cavity generate stronger beam-wave interaction, the energy is transferred to electromagnetic waves, and finally, the generated output signals are radiated out through the annular output cavity.

The present invention provides an extended interaction klystron in which the resonating section and the grating section have different lateral dimensions. According to the distribution characteristics of coaxial high-order TM mode electric fields, the adjacent electric field extreme values can be equivalent to an ideal electric wall, and the working mode electric field extreme values are respectively positioned in each resonance part and each grating part (a fan-shaped cavity). In addition, the invention uses TM51-2 pi mode as interaction mode, and under the same frequency operation, the transverse TM51 mode has larger transverse cavity size than the TM01 mode. Meanwhile, according to the injection-wave synchronization condition, the axial 2 pi mode enables the cavity to have the largest axial size, so that the power capacity and the heat dissipation performance of the cavity can be improved, and the millimeter wave high-power application scene is more suitable. Further, compared with the existing angular uniform coupling structure, the design enables the interaction electric field to be more concentrated near the electron beam channel, so that the characteristic impedance of the beam-wave interaction position is improved.

The embodiments of the present disclosure have been described above. However, these examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although the embodiments are described separately above, this does not mean that the measures in the embodiments cannot be used in advantageous combination. The scope of the disclosure is defined by the appended claims and equivalents thereof. Various alternatives and modifications can be devised by those skilled in the art without departing from the scope of the present disclosure, and such alternatives and modifications are intended to be within the scope of the present disclosure.

Claims

1. An extended interaction klystron, comprising: -a body (1), said body (1) having a cylindrical external profile, inside said body (1) there being formed:

a first resonant cavity, a second resonant cavity, and at least one intermediate resonant cavity located between the first resonant cavity and the second resonant cavity, which are coaxially arranged in an axial direction of the body (1), each of the first resonant cavity, the second resonant cavity, and the intermediate resonant cavity including:

a plurality of resonance sections (6) distributed at intervals in the circumferential direction in the body (1); and

a plurality of grating portions (4) arranged to alternate with the plurality of resonance portions (6) in the circumferential direction within the body (1), each grating portion (4) communicating with two adjacent resonance portions (6), wherein at least one grating portion (4) of a first resonant cavity communicates with an input waveguide, at least one grating portion (4) of a second resonant cavity communicates with an output waveguide, and

a plurality of electron beam channels (2), each electron beam channel (2) extending through the body (1) in the axial direction and communicating with grating portions (4) of the first, second and intermediate resonant cavities that are aligned in the axial direction.

2. Klystron as claimed in claim 1, wherein each said grating portion (4) comprises a plurality of fan-shaped resonant gaps (41) spaced in said axial direction and extending in a radial direction.

3. The klystron of claim 2, wherein the input waveguide comprises:

an annular input cavity (30) extending from a first end of the body (1) in the axial direction into the body (1) and communicating with one of the fan-shaped resonant gaps (41) of the grating portion (4) of the first resonant cavity;

the output waveguide includes:

and the annular output cavity (50) extends from the second end of the axial direction of the body (1) to the inside of the body (1) and is communicated with one fan-shaped resonant gap (41) of the grating part (4) of the second resonant cavity.

4. The klystron of claim 3, wherein the body is further formed with:

an input waveguide transition portion (32), the input waveguide transition portion (32) being formed as a cavity integrally extending from an inner side of an axial direction of the ring-shaped input cavity (30) toward an inner side of a radial direction of a sector resonance gap (41) of the first resonance cavity, the input waveguide transition portion (32) communicating with one sector resonance gap (41) of the first resonance cavity; and

an output waveguide transition portion (52), the output waveguide transition portion (52) being formed as a cavity integrally extending from an inner side of the annular output cavity (50) in an axial direction toward an inner side of a radial direction of a sector resonance gap (41) of the second resonance cavity, the output waveguide transition portion (52) communicating with one sector resonance gap (41) of the second resonance cavity.

5. The klystron of claim 4, said input waveguide transition (32) and said sector resonant gap (41) communicating through a sector input coupling hole (31);

the output waveguide conversion section (52) communicates with the sector resonance gap (41) via a sector output coupling hole (51).

6. Klystron as claimed in claim 1, wherein the center-to-center distance (a) between two adjacent sector resonances in the grating part (4) is taken as one period length of the grating part (4);

the width (b) of each fan-shaped resonant gap (41) in the grating part (4) is the same, and the width (b) of each fan-shaped resonant gap (41) is 1/3-1/2 times of the period length of the fan-shaped resonant gap (41).

7. Klystron as claimed in claim 1, wherein said resonance section (6) has a width (c) N times the period length of said fan-shaped resonance gap (41), where N is characterized by the number of said fan-shaped resonance gaps (41) in one of said grating sections (4) communicating with said resonance section (6).

8. The klystron of claim 1, wherein an inner diameter of the electron beam channel (2) is 1/6-1/4 times the operating wavelength of the klystron.

9. The klystron of claim 1, wherein each of the first resonant cavity, second resonant cavity, and intermediate resonant cavity comprises:

5 multiple resonance parts (6) and 5 grating parts (4);

wherein each grating portion (4) of the first resonant cavity comprises 3-5 fan-shaped resonant gaps (41);

wherein each grating portion (4) of the intermediate resonant cavity comprises 3-5 fan-shaped resonant gaps (41);

wherein each grating portion (4) of the second resonant cavity comprises 5-7 fan-shaped resonant gaps (41).

10. Klystron as claimed in claim 9, wherein the arc (β) of the resonance section (6) of each of the first, second and intermediate resonance cavities is 28-32 °;

the arc of each of the fan-shaped resonance gaps of the grating portion (4) of each of the first, second and intermediate resonant cavities is 44-40 ° (a);

the geometric centers of each of the fan-shaped resonance gap (41) and the resonance part (6) are located on the same concentric circle.