Broadband efficient circular waveguide TE31 mode exciter

Abstract

The invention discloses a broadband efficient circular waveguide TE31 mode exciter, and belongs to the technical field of microwaves and millimeter waves. The exciter comprises a standard TE10 mode rectangular waveguide section, a TE10mode-TE30 mode conversion section, a standard TE30 mode rectangular waveguide section, a TE30 mode-circular waveguide TE31 mode conversion section and a TE31 mode circular waveguide section which are connected in sequence. The excitation process of the TE31 mode exciter is divided into two steps, a TE10 mode is converted into a TE30 mode, and then the TE30 mode is converted into a TE31 mode; under the cooperation of the power divider, the torsion waveguide and the gradual change waveguide, the conversion from a rectangular waveguide TE10 mode to a circular waveguide TE31 mode is realized, the loss in the conversion process is reduced, and the conversion efficiency is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of microwaves and millimeter waves, and in particular relates to a broadband and efficient circular waveguide TE 31 mode exciter. Background Art

[0002] Gyrotron is a high-power millimeter wave and terahertz wave amplifier device that can be used in radar, communication, electronic countermeasures and other fields. Gyrotron amplifies electromagnetic wave signals by utilizing the interaction between electron beam and magnetic field. As an important high-power millimeter wave and terahertz wave source, gyrotron has a wider working bandwidth than traditional high-power devices such as klystron, gyrotron and gyroklystron, and has broad application prospects.

[0003] During the development of a gyrotron traveling wave tube, it is usually necessary to measure the performance of its high-frequency system, such as the attenuation and dispersion characteristics of the gyrotron traveling wave tube's high-frequency interaction circuit in the working mode and the competition mode, and the transmission and reflection characteristics of the input coupler and output window in the working mode.

[0004] Vector network analyzer is a common measuring instrument, and it is also one of the most commonly used and reliable instruments for measuring microwave and millimeter wave devices. However, the output and input ports of vector network analyzer are generally coaxial structures or rectangular structures. However, the high-frequency interaction circuit of a gyrotron traveling wave tube is usually a circular waveguide structure, and the working mode and competition mode are both circular waveguide TEmn modes. Therefore, when testing the propagation characteristics of the high-frequency interaction circuit of a gyrotron traveling wave tube, it is necessary to develop a corresponding mode exciter according to the working mode and competition mode.

[0005] Mode exciters are widely used in microwave, millimeter wave and terahertz wave systems. They use different waveguide geometric structures to realize the excitation conversion from one waveguide mode to another. The development of mode exciters usually requires high conversion efficiency and broadband characteristics. However, the existing circular waveguide TE31 mode exciter design has the problems of narrow bandwidth (relative bandwidth effect 5%) and low conversion efficiency (mode conversion efficiency is generally less than 90%), which can hardly meet the needs of testing the dispersion and attenuation characteristics of the main competing mode TE31 mode when developing a large cyclotron electron beam second harmonic TE21 mode cyclotron traveling wave tube. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention proposes a broadband and high-efficiency circular waveguide TE31 mode exciter.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A broadband high-efficiency circular waveguide TE31 mode exciter comprises a standard TE10 mode rectangular waveguide section (1), a TE10 mode-TE30 mode conversion section (2), a standard TE30 mode rectangular waveguide section (3), a TE30 mode-circular waveguide TE31 mode conversion section (4), and a TE31 mode circular waveguide section (5) which are connected in sequence.

[0009] The standard TE10 mode rectangular waveguide section is used to transmit the TE10 mode to the TE10 mode-TE30 mode conversion section.

[0010] The TE10 mode-TE30 mode conversion section comprises a one-to-two power divider (21), a two-to-three power divider (22), three twisted waveguides (23), a TE30 mode synthesis section (24), and a TE30 mode transition section (25); wherein the one-to-two power divider is used to divide the input TE10 mode into two paths and transmit the paths to the two-to-three power divider; the two-to-three power divider is used to divide the two paths of the input TE10 mode into three paths and respectively input the three twisted waveguides; the twisted waveguide is used to transmit the TE10 mode To the TE30 mode synthesis section, the torsional waveguide located in the middle and the torsional waveguide located at the side respectively rotate the polarization direction of the input TE10 mode by 90 degrees in the opposite direction, so that the three-way electromagnetic field meets the field distribution of the rectangular waveguide TE30 mode; the TE30 mode synthesis section is used to synthesize the input three-way TE10 mode into one TE30 mode and transmit it to the TE30 mode transition section; the TE30 mode transition section is used to transition the output port of the TE30 mode synthesis section to the input port of the standard TE30 mode rectangular waveguide.

[0011] The standard TE30 mode rectangular waveguide section is used to transmit the TE30 mode to the TE30 mode-circular waveguide TE31 mode conversion section.

[0012] The TE30 mode-circular waveguide TE31 mode conversion section is used to convert the input rectangular waveguide TE30 mode into the circular waveguide TE31 mode and transmit it to the TE31 mode circular waveguide section.

[0013] The TE31 mode circular waveguide section is used to output the TE31 mode to the circular waveguide of the subsequent stage.

[0014] Preferably, the TE30 mode-circular waveguide TE31 mode conversion section comprises an axially cascaded rectangular waveguide transformation section (41) and a rectangular waveguide-circular waveguide transformation section (42); wherein the rectangular waveguide transformation section has a constant wide side and a linearly increasing narrow side; and the rectangular waveguide-circular waveguide transformation section uniformly and gradually transforms the rectangular output port of the rectangular waveguide transformation section to the input port of the TE31 mode circular waveguide section.

[0015] Preferably, the TE30 mold synthesis section includes three rectangular input ports and one rectangular output port; the narrow sides of the three rectangular input ports are close to each other and uniformly change along the axial direction to form a rectangular output port.

[0016] Preferably, the narrow side of the TE30 mode transition section remains unchanged, and the wide side decreases linearly.

[0017] Preferably, the narrow side size of the standard TE30 mode rectangular waveguide segment is the same as the narrow side size of the standard TE10 mode rectangular waveguide segment, and the wide side size is 3 times the wide side size of the standard TE10 mode rectangular waveguide segment.

[0018] The working principle of the present invention is as follows: electromagnetic waves of the TE10 mode transmitted by a standard rectangular waveguide are divided into three paths of equal amplitude and same direction through two groups of power dividers; the three paths of the TE10 mode with the same direction are converted into a polarization direction that conforms to the TE30 mode of the rectangular waveguide through the reverse twisting action of the twisting waveguide; the three paths of electromagnetic fields are combined into one path through the TE30 mode synthesis section, and at this time, a non-standard rectangular waveguide TE30 mode is obtained; the non-standard rectangular waveguide TE30 mode is then converted into a standard TE30 mode rectangular waveguide through the TE30 mode transition section; finally, the standard rectangular waveguide TE30 mode is gradually converted into the TE31 mode of the circular waveguide through two sections of gradient waveguides in the TE30 mode-circular waveguide TE31 mode conversion section, and is output through the subsequent circular waveguide section.

[0019] The present invention has the following technical effects: The present invention proposes a broadband, efficient circular waveguide TE31 mode exciter. With the cooperation of a power divider, a twisted waveguide and a gradient waveguide, the conversion from a rectangular waveguide TE10 mode to a circular waveguide TE31 mode is realized. The entire excitation process is divided into two steps, which reduces the loss in the conversion process and ensures the conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a three-dimensional structure diagram of the circular waveguide TE31 mode exciter of the present invention;

[0021] Figure 2 Dimensions of the circular waveguide TE31 mode exciter of this embodiment;

[0022] Figure 3 The field distribution diagram of the input and output ends of the circular waveguide TE31 mode exciter in this embodiment;

[0023] Figure 4 Schematic diagram of the twisted waveguide structure in this embodiment;

[0024] Figure 5 The field distribution diagrams of the three twist waveguide input and output ends in this embodiment;

[0025] Figure 6is a graph showing the relationship between the return loss and frequency of the input port of the circular waveguide TE31 mode exciter in the Q band of this embodiment;

[0026] Figure 7 FIG. 4 is a graph showing the relationship between the conversion efficiency and frequency of the circular waveguide TE31 mode exciter in the Q band of this embodiment. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0028] This embodiment provides a broadband and efficient circular waveguide TE31 mode exciter. Figure 1 As shown, it includes a standard TE10 mode rectangular waveguide section (1), a TE10 mode-TE30 mode conversion section (2), a standard TE30 mode rectangular waveguide section (3), a TE30 mode-circular waveguide TE31 mode conversion section (4), and a TE31 mode circular waveguide section (5) connected in sequence.

[0029] like Figure 2 As shown, the standard TE10 mode rectangular waveguide section uses a BJ400 standard rectangular waveguide with dimensions of a1*b1*c1=5.69mm*2.845mm*5mm, and is used to transmit the TE10 mode to the TE10 mode-TE 30 mode conversion section.

[0030] like Figure 2 As shown, the TE10 mode-TE30 mode conversion section includes a one-to-two power divider (21), a two-to-three power divider (22), three twisted waveguides (23), a TE30 mode synthesis section (24), and a TE30 mode transition section (25).

[0031] The one-to-two power splitter is used to split the input TE10 mode into two paths and transmit them to the two-to-three power splitter. The two-to-three power splitter is used to split the two input TE10 modes into three paths and input them into three twisted waveguides respectively. The twisted waveguide is used to transmit the TE10 mode to the TE30 mode synthesis section. Figure 4 As shown in the figure, the twisted waveguide located in the middle and the twisted waveguide located at the side respectively rotate the polarization direction of the input TE10 mode by 90 degrees in the opposite direction, so that the three-way electromagnetic field meets the field distribution of the rectangular waveguide TE30 mode. The field distribution before and after the twisted waveguide is shown in Figure 5 The TE30 mode synthesis section is used to synthesize the three input TE10 modes into one TE30 mode and transmit it to the TE30 mode transition section. The TE30 mode transition section is used to transition the output port of the TE30 mode synthesis section to the input port of the standard TE30 mode rectangular waveguide.

[0032] Specifically, the twist waveguide adopts a rectangular twist waveguide with an arbitrary angle change disclosed in the application number "2024116521233", such as Figure 4 As shown, the twist waveguide includes an input rectangular waveguide, a "three-circular" twist waveguide, and an output rectangular waveguide; wherein the dimensions of the input rectangular waveguide and the output rectangular waveguide are a2*b2=5.69mm*2.845mm, the radius of the small circular hole of the "three-circular" twist waveguide is r1=1.45mm, the radius of the large circular hole is r2=2.25mm, and the center spacing of the large circular holes is d=4.9mm. The angles between the three-way input rectangular waveguide and the output rectangular waveguide are all 90 degrees, the angle between the central axis of the middle twist waveguide and the center line of the narrow sides of the waveguides on both sides is 45 degrees, and the angle between the central axis of the side twist waveguide and the center line of the narrow sides of the waveguides on both sides is also 45 degrees, but the direction is opposite to that of the middle twist waveguide.

[0033] The TE30 mold synthesis section includes three rectangular input ports and one rectangular output port with a length of 32 mm; the narrow sides of the three rectangular input ports are close to each other and change evenly along the axial direction to form a rectangular output port with a size of a3*b3=20.27mm*2.845mm.

[0034] The narrow side of the TE30 module transition section remains unchanged, the wide side decreases linearly, the length is 34.51 mm, and the size of the output port is a4*b4=17.07 mm*2.845 mm.

[0035] The size of the standard TE30 mode rectangular waveguide section is a4*b4*c4=17.07mm*2.845mm*11.2mm, and is used to transmit the TE30 mode to the TE30 mode-circular waveguide TE31 mode conversion section.

[0036] The TE30 mode-circular waveguide TE31 mode conversion section is used to convert the input rectangular waveguide TE30 mode into a circular waveguide TE31 mode and transmit it to the TE31 mode circular waveguide section. Specifically, the TE30 mode-circular waveguide TE31 mode conversion section includes an axially cascaded rectangular waveguide conversion section (41) and a rectangular waveguide-circular waveguide conversion section (42); wherein the length of the rectangular waveguide conversion section is 39 mm, the wide side remains unchanged, the narrow side increases linearly, and the output port size is a5*b5=17.07 mm*8.535 mm; the length of the rectangular waveguide-circular waveguide conversion section is 61.6 mm, and the rectangular output port of the rectangular waveguide conversion section is uniformly and gradually transformed to the input port of the TE31 mode circular waveguide section.

[0037] The length of the TE31 mode circular waveguide section is h=10 mm, and the radius is r=8 mm, and is used to output the TE31 mode to the circular waveguide of the subsequent stage.

[0038] Figure 3Shown are the field distribution diagrams at the input and output ends of the circular waveguide TE31 mode exciter of this embodiment. It can be seen that the circular waveguide TE31 mode exciter obtained in this embodiment can successfully convert the TE10 mode of the rectangular waveguide into the TE31 mode of the circular waveguide.

[0039] Figure 6 2 is a graph showing the relationship between the return loss of the input port of the circular waveguide TE31 mode exciter in the Q band and the frequency in this embodiment. It can be seen that the return loss of the input port in the Q band is substantially less than 20 dB, ie, less than 1%.

[0040] Figure 7 : is a graph showing the relationship between the conversion efficiency and frequency of the circular waveguide TE31 mode exciter in the Q band in this embodiment. It can be seen that the conversion efficiency of the mode exciter in the Q band can reach more than 94%.

[0041] In summary, the circular waveguide TE31 mode exciter proposed in the present invention has lower loss and higher conversion efficiency.

Claims

1. A broadband high-efficiency circular waveguide TE31 mode exciter, characterized in that: The invention comprises a standard TE10 mode rectangular waveguide section (1), a TE10 mode-TE30 mode conversion section (2), a standard TE30 mode rectangular waveguide section (3), a TE30 mode-circular waveguide TE31 mode conversion section (4), and a TE31 mode circular waveguide section (5) which are connected in sequence. The standard TE10 mode rectangular waveguide section is used to transmit the TE10 mode to the TE10 mode-TE30 mode conversion section; The TE10 mode-TE30 mode conversion section comprises a one-to-two power divider (21), a two-to-three power divider (22), three twisted waveguides (23), a TE30 mode synthesis section (24), and a TE30 mode transition section (25); wherein the one-to-two power divider is used to divide the input TE10 mode into two paths and transmit the paths to the two-to-three power divider; the two-to-three power divider is used to divide the two paths of the input TE10 mode into three paths and respectively input the three twisted waveguides; the twisted waveguide is used to transmit the TE10 mode To the TE30 mode synthesis section, and the twisted waveguide located in the middle and the twisted waveguide located in the side respectively rotate the polarization direction of the input TE10 mode by 90 degrees in the opposite direction, so that the three-way electromagnetic field meets the field distribution of the rectangular waveguide TE30 mode; the TE30 mode synthesis section is used to synthesize the input three-way TE10 mode into one TE30 mode and transmit it to the TE30 mode transition section; the TE30 mode transition section is used to transition the output port of the TE30 mode synthesis section to the input end of the standard TE30 mode rectangular waveguide; The standard TE30 mode rectangular waveguide section is used to transmit the TE30 mode to the TE30 mode-circular waveguide TE31 mode conversion section; The TE30 mode-circular waveguide TE31 mode conversion section is used to convert the input rectangular waveguide TE30 mode into the circular waveguide TE31 mode and transmit it to the TE31 mode circular waveguide section; The TE31 mode circular waveguide section is used to output the TE31 mode to the circular waveguide of the subsequent stage.

2. A broadband high-efficiency circular waveguide TE31 mode exciter as claimed in claim 1, characterized in that: The TE30 mode-circular waveguide TE31 mode conversion section comprises an axially cascaded rectangular waveguide transformation section (41) and a rectangular waveguide-circular waveguide transformation section (42); wherein the rectangular waveguide transformation section has a constant wide side and a linearly increasing narrow side; and the rectangular waveguide-circular waveguide transformation section uniformly and gradually transforms the rectangular output port of the rectangular waveguide transformation section to the input port of the TE31 mode circular waveguide section.

3. A broadband high-efficiency circular waveguide TE31 mode exciter as claimed in claim 1 or 2, characterized in that: The TE30 mold synthesis section includes three rectangular input ports and one rectangular output port; the narrow sides of the three rectangular input ports are close to each other and uniformly change along the axial direction to form a rectangular output port.

4. A broadband high-efficiency circular waveguide TE31 mode exciter as claimed in claim 3, characterized in that: The narrow side of the TE30 mode transition section remains unchanged, and the wide side decreases linearly.

5. A broadband high-efficiency circular waveguide TE31 mode exciter as claimed in claim 4, characterized in that: The narrow side size of the standard TE30 mode rectangular waveguide section is the same as the narrow side size of the standard TE10 mode rectangular waveguide section, and the wide side size is three times the wide side size of the standard TE10 mode rectangular waveguide section.

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