Ridge loading multipath synthesis TE02 mode input coupler with high electron beam flow rate

Abstract

The invention discloses a ridge loading multipath synthesis TE02 mode input coupler with a high electron beam flow rate, and belongs to the technical field of microwave and millimeter wave electric vacuum devices. The input coupler comprises a power distribution network part, a ridge loading multipath synthesis part and a three-stage cascade circular reflection waveguide part. The waveguide ridge is arranged on the side wall of the main circular waveguide, and the length, the width and the depth of the waveguide ridge are adjusted to suppress main competition modes (TE01 and TE41) of a TE02 mode in the main circular waveguide, so that the effects of suppressing a miscellaneous mode, reducing a reflection coefficient, improving conversion efficiency and expanding input bandwidth are achieved. Meanwhile, the cascade circular reflecting waveguide can totally reflect a TE02 mode, and the inner radius of the cascade circular reflecting waveguide is larger than that of a cut-off waveguide of a traditional input coupler, so that the probability of electron interception is reduced, and the flow rate of electron beams is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave, millimeter wave and terahertz devices, and particularly relates to a ridge-loaded multi-path synthesized TE with high electron beam flux. 02 Mode input coupler can be used in gyrotron traveling wave tubes in millimeter wave and terahertz bands. Background Art

[0002] As an electric vacuum device based on the electron cyclotron maser mechanism, the gyrotron traveling wave tube amplifier has broad application prospects in modern high-performance radar, wireless communications, security imaging and other fields because of its wide bandwidth, high power and high efficiency in the millimeter wave and even terahertz frequency bands.

[0003] The input coupler is a key component of the gyrotron traveling wave tube input system. It is located between the electron gun and the high-frequency structure. Its main function is to couple the input microwave signal into the circular waveguide to stimulate the working mode required by the gyrotron traveling wave tube. Therefore, the input coupler needs to meet the characteristics of high conversion efficiency, high mode purity, high power capacity, simple processing, and compact structure in the design process to ensure the good working performance of the gyrotron traveling wave tube. The input coupler is a three-port device. The input port is a standard rectangular waveguide connected to a rectangular waveguide. The two output ports are both circular waveguides and are respectively connected to the electron gun and the injection-wave interaction region. For the traditional gyrotron traveling wave tube input coupler, in order to prevent the input electromagnetic wave from propagating in reverse, a waveguide that is cut off for the working mode is usually set between the input coupler and the transition section. However, the radius of the cutoff waveguide is generally 0.8-0.9 times the radius of the circular waveguide of the input coupler, which will cause a part of the electron beam to be intercepted when passing through the cutoff section.

[0004] In previous research on gyrotron traveling wave tube input couplers, low-order modes (such as TE 01 TE 11 However, with the expansion of application fields and the urgent need for high-power gyrotron traveling wave tubes, research on gyrotron traveling wave tubes using high-order modes as working modes has gradually begun. 02 The difficulty of the gyrotron traveling wave tube input coupler working in the TE mode is 02 The mode is a high-order mode, with many competing modes and difficult to suppress, low conversion efficiency, and limited available bandwidth. It is difficult to obtain a high-purity TE using traditional design methods. 02 mold. Summary of the invention

[0005] In order to solve the problem of cyclotron traveling wave tube TE 02The present invention proposes a ridge-loaded multi-channel synthesized TE with high electron beam flux. 02 Mode input coupler, which adds ridges uniformly in the circular waveguide and uses a multi-channel synthesis structure to couple high-purity TE in the circular waveguide 02 The TE mode in the main circular waveguide is suppressed by changing the size, position distribution and depth of the ridges on the side wall of the main circular waveguide. 02 The main competitive mode of the model (TE 01 ,TE 41 ) field distribution, improve impedance matching, thereby achieving the effect of suppressing heterogeneous modes, reducing reflection coefficient, improving conversion efficiency, and increasing bandwidth. In addition, the use of three-stage cascaded circular reflection waveguides to replace traditional cutoff waveguides can improve TE 02 The mode is totally reflected. This structure can make the waveguide radius of the cutoff section larger than that of the traditional structure, thereby reducing the probability of electron interception.

[0006] The present invention is implemented by the following technical solutions:

[0007] A ridge-loaded multiplexed TE synthesis with high electron beam flux 02 Mode input coupler, used in 210-230GHz frequency band, working mode is TE 02 mode; the structure includes a power distribution network part, a ridge-loaded multiplexing part and a three-stage cascaded circular reflection waveguide part.

[0008] The power distribution network part includes a standard rectangular waveguide 1, a T-type power divider 3, two T-type power dividers 5, and two transition waveguides 4; TE 10 The analog microwave signal is input into a standard rectangular waveguide and is divided into two equal-amplitude half-microwave signals by a T-type power divider 3; each half-microwave signal is input into a T-type power divider 5 through a transition waveguide 4 and is divided into two equal-amplitude quarter-microwave signals, thereby finally achieving radially uniform distribution of the output four equal-amplitude microwave signals.

[0009] The power distribution network part is located on the same horizontal plane, and the T-type power divider 3 and the T-type power divider 5 have the same size.

[0010] The T-type power divider 3 and the T-type power divider 5 are both provided with matching grooves for reducing the reflection coefficient of the T-type power divider.

[0011] The ridge-loaded multi-path synthesis part includes a main circular waveguide, four-path rectangular waveguides, and eight waveguide ridges.

[0012] The radius of the main circular waveguide is the same as the radius of the gyrotron traveling wave tube injection-wave interaction high-frequency system.

[0013] The waveguide ridges are evenly distributed on the inner wall of the main circular waveguide in an angular direction and have the same spacing as adjacent coupling holes.

[0014] The four equal-amplitude microwave signals output by the power distribution network are respectively input into a rectangular waveguide, and then injected into the main circular waveguide through a coupling hole, and finally synthesized into TE in the main circular waveguide. 02 mold.

[0015] The three-stage cascade circular reflection waveguide part comprises a first-stage circular reflection waveguide, a second-stage circular reflection waveguide and a third-stage circular reflection waveguide which are arranged at intervals.

[0016] Furthermore, the inner cavity radius lengths of the first to third stage circular reflection waveguides are all the same.

[0017] Furthermore, the cavity of the main circular waveguide is completely connected with the cavities of each stage of the three-stage cascade circular reflection waveguide.

[0018] The beneficial effects of the present invention are:

[0019] (1) Ridge-loaded multi-channel synthesis TE with high electron beam flux designed by the present invention 02 The mode input coupler is a high-order mode, broadband input coupler, with a -1dB relative bandwidth of 6.1% (213-226.5GHz); a -3dB relative bandwidth of 9.1% (210-230GHz); and a reflection coefficient lower than -12dB.

[0020] (2) Ridges are added uniformly in the angular direction on the side wall of the main circular waveguide. The competing modes can be effectively suppressed by changing the size and position distribution of the ridges.

[0021] (3) Using a cascaded reflection cavity structure to replace the cutoff waveguide section can increase the radius while achieving TE 02 The total reflection of the mode reduces the probability of the electron beam being intercepted. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Ridge-loaded multiplexed TE with high electron beam flux rate of the present invention 02 Schematic diagram of the 3D structure of the mode input coupler.

[0023] Figure 2 Ridge-loaded multiplexed TE with high electron beam flux rate of the present invention 02 Side view of the mode input coupler.

[0024] Figure 3 Ridge-loaded multiplexed TE with high electron beam flux rate of the present invention 02 TE of the mode input coupler 02 TE 01TE 41 Transmission coefficient.

[0025] Figure 4 Ridge-loaded multiplexed TE with high electron beam flux rate of the present invention 02 Reflection coefficient of the mode input coupler. DETAILED DESCRIPTION

[0026] The present invention is further elaborated below in combination with a design example and the accompanying drawings. It is necessary to point out here that this embodiment is only used to further illustrate the present invention and cannot be understood as a limitation on the protection of the present invention. Technical personnel familiar with the field can make some non-essential improvements and adjustments based on the above-mentioned contents of the present invention.

[0027] The working band of this embodiment is 210-230 GHz.

[0028] Figure 1 Multiplexed synthetic TE for ridge loading with high electron beam flux 02 Schematic diagram of the 3D structure of the mode input coupler; Figure 2 Multiplexed synthetic TE for ridge loading with high electron beam flux 02 Side view of the mode input coupler. This embodiment includes: power distribution network part: standard rectangular waveguide 1, matching groove 2, T-type power divider 3, transition waveguide 4, T-type power divider 5, transition waveguide 6. Ridge-loaded multiplexing part: waveguide ridge 7, main circular waveguide 8, rectangular waveguide 9. Three-stage cascade circular reflection waveguide part: first-stage circular reflection waveguide 10, second-stage circular reflection waveguide 11, third-stage circular reflection waveguide 12.

[0029] 1. Power distribution network part

[0030] Standard rectangular waveguide 1 is a standard rectangular waveguide (BJ2200): wide side size 1.092mm, narrow side size 0.546mm.

[0031] Matching groove 2: wide side dimension 1.092mm, narrow side dimension 0.68mm, depth 0.21mm.

[0032] T-type power divider 3: input port size: wide side size 1.092mm, narrow side size 0.546mm; two arm sizes: wide side size 1.092mm, narrow side size 0.546mm; the two T-type power dividers 5 are equal to the T-type power divider 3 in size.

[0033] Transition waveguide 4: realizes 90° turn, with wide side dimension of 1.092mm and narrow side dimension of 0.546mm.

[0034] Transition waveguide 6: achieves a 135° turn, with a wide side dimension of 1.092mm and a narrow side dimension of 0.546mm.

[0035] 2. Ridge loading multiplex synthesis part

[0036] Waveguide ridge 7: wide side dimension: 0.7mm, narrow side dimension: 0.18mm, depth: 0.28mm.

[0037] Main circular waveguide 8: Radius: 1.6mm, Length: 5mm

[0038] Rectangular waveguide 9: wide side size: 1.092mm, narrow side size: 0546mm.

[0039] 3. Three-stage cascade circular reflection waveguide

[0040] First-stage circular reflection waveguide 10: radius: 2.44 mm, length: 0.84 mm.

[0041] Second-order circular reflected wave 11: radius: 2.8 mm, length: 1.1 mm.

[0042] The third-stage circular reflection waveguide 12 has the following characteristics: radius: 1.8 mm, length: 0.6 mm.

[0043] In addition, θ1=90°, θ2=135°.

[0044] Figure 3 Ridge-loaded multiplexed TE with high electron beam flux rate of the present invention 02 TE of the mode input coupler 02 TE 01 TE 41 Transmission coefficient. As can be seen from the figure, TE 02 The transmission coefficient of the mode S 21 The bandwidth greater than -1dB covers the range from 213GHz to 226.5GHz, and the bandwidth above -3dB covers the range from 210GHz to 230GHz, with a wide operating bandwidth. 10 Mode to other mode (TE 01 TE 41 ) has a relatively low transmission parameter, which is below -12dB in the frequency range of 210GHz to 220GHz. It can be seen that the competition mode is well suppressed, thus achieving TE 10 -TE 02 High-efficiency mode conversion, outputting a circular waveguide TE with high purity 02 mold.

[0045] Figure 4 Ridge-loaded multiplexed TE with high electron beam flux rate of the present invention 02Reflection coefficient of the mode input coupler. It can be seen from the figure that the reflection coefficient of the gyrotron traveling wave tube input coupler is around -15dB in the frequency range of 210GHz to 230GHz.

[0046] The above examples are only for the convenience of explaining the present invention. The novel gyrotron traveling wave tube input coupler proposed in the present invention can also be applied to other frequency bands, and the specific size is determined by the corresponding frequency band and working mode.

Claims

1. A ridge-loaded multiplexed TE with high electron beam flux 02 Mode input coupler, used in 210-230GHz frequency band, working mode is TE 02 The structure includes a power distribution network part, a ridge-loaded multiplexing part and a three-stage cascaded circular reflection waveguide part; The power distribution network part will be a standard rectangular waveguide TE at the input end 10 The modulated microwave signal is equally divided into four equal-amplitude microwave signals uniformly distributed along the radial direction; the ridge-loaded multi-path synthesis part includes a main circular waveguide, four rectangular waveguides, and eight waveguide ridges; the radius of the main circular waveguide is the same as the radius of the gyrotron traveling wave tube injection-wave interaction high-frequency system; the three-stage cascade circular reflection waveguide part includes a first-stage circular reflection waveguide, a second-stage circular reflection waveguide, and a third-stage circular reflection waveguide arranged at intervals, and the inner cavity radius lengths of the first-stage to the third-stage circular reflection waveguides are all the same; the cavity of the main circular waveguide is completely connected with the cavities of each stage of the three-stage cascade circular reflection waveguide.

2. A ridge loaded multiplexed TE with high electron beam flux as claimed in claim 1 02 An input coupler, characterized in that The power distribution part includes a standard rectangular waveguide 1, a T-type power divider 3, and two T-type power dividers 5; TE 10 The analog microwave signal is input into a standard rectangular waveguide and is divided into two equal-amplitude half-microwave signals by a T-type power divider 3; each half-microwave signal is input into a T-type power divider 5 through a transition waveguide 4 and is divided into two equal-amplitude quarter-microwave signals, thereby finally achieving radially uniform distribution of the output four equal-amplitude microwave signals.

3. A ridge loaded multiplexed TE with high electron beam flux as claimed in claim 1 02 mode input coupler, characterized in that The length of the waveguide ridge ranges from 0.6 mm to 0.75 mm, the width ranges from 0.15 mm to 0.2 mm, and the depth ranges from 0.2 to 0.

3.

4. A ridge loaded multiplexed TE with high electron beam flux as claimed in claim 1 02 mode input coupler, characterized in that The length of the first-stage circular reflection waveguide is 0.84 mm and the radius is 2.44 mm; the length of the second-stage circular reflection waveguide is 1.1 mm and the radius is 2.8 mm; the length of the third-stage circular reflection waveguide is 0.6 mm and the radius is 1.8 mm.

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