A broadband and efficient circular waveguide TE31 mode exciter

Abstract

The present invention discloses a broadband, high-efficiency circular waveguide TE31 mode exciter, belonging to the field of microwave and millimeter wave technology. The exciter comprises a standard TE10 mode rectangular waveguide section, a TE10 mode-TE30 mode conversion section, a standard TE30 mode rectangular waveguide section, a TE30 mode-TE31 mode conversion section, and a TE31 mode circular waveguide section, all connected in sequence. The excitation process of the TE31 mode exciter is divided into two steps: first, converting the TE10 mode to the TE30 mode, and then converting it to the TE31 mode. With the cooperation of a power divider, a torsion waveguide, and a gradient waveguide, the conversion from the rectangular waveguide TE10 mode to the circular waveguide TE31 mode is achieved, reducing losses during the conversion process and ensuring conversion efficiency.

Description

Technical Field

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

[0002] Gyrotrons (GWTs) are high-power millimeter-wave and terahertz wave amplifiers used in radar, communications, electronic countermeasures, and other fields. They amplify electromagnetic signals by exploiting the interaction between an electron beam and a magnetic field. As an important source of high-power millimeter-wave and terahertz waves, GWTs offer a wider operating bandwidth than conventional high-power devices such as klystrons, gyrotrons, and gyroklystrons, offering broad application prospects.

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

[0004] The vector network analyzer (VNA) is a common measuring instrument and one of the most commonly used and reliable instruments for measuring microwave and millimeter-wave devices. However, the output and input ports of a VNA are typically coaxial or rectangular. However, the high-frequency interaction circuit of a gyrotron traveling wave tube (TWT) is typically a circular waveguide structure, and both the operating and competitive modes are TEmn modes. Therefore, when testing the propagation characteristics of a TWT's high-frequency interaction circuit, it is necessary to develop a mode driver tailored to the operating and competitive modes.

[0005] Mode exciters are widely used in microwave, millimeter-wave, and terahertz wave systems. They utilize different waveguide geometries to achieve the excitation conversion from one waveguide mode to another. The development of mode exciters typically requires high conversion efficiency and broadband characteristics. However, existing circular waveguide TE31 mode exciter designs suffer from narrow bandwidth (relative bandwidth effect 5%) and low conversion efficiency (mode conversion efficiency is generally less than 90%). These issues make it difficult to meet the requirements for testing the dispersion and attenuation characteristics of the TE31 mode, the primary competing mode, when developing large cyclotron electron beam second harmonic TE21 mode gyrotron traveling wave tubes. 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 in 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 includes a one-to-two power splitter (21), a two-to-three power splitter (22), three twisted waveguides (23), a TE30 mode synthesis section (24), and a TE30 mode transition section (25); wherein the one-to-two power splitter is used to divide the input TE10 mode into two equal paths and transmit the divided TE10 mode to the two-to-three power splitter; the two-to-three power splitter is used to divide the two input TE10 modes into three equal paths and input the three twisted waveguides respectively; the twisted waveguide is used to transmit the TE10 mode to the three twisted waveguides. To the TE30 mode synthesis section, the torsional waveguide located in the middle and the torsional waveguide located on the side respectively rotate the polarization direction of the input TE10 mode 90 degrees in opposite directions, 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 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.

[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 three times the wide side size of the standard TE10 mode rectangular waveguide segment.

[0018] The working principle of the present invention is as follows: the TE10 mode electromagnetic wave transmitted by the standard rectangular waveguide is divided into three equal-amplitude and same-direction paths through two groups of power dividers; the three same-direction TE10 modes are converted into a polarization direction consistent with the rectangular waveguide TE30 mode through the reverse twisting action of the torsional waveguide; the three electromagnetic fields are combined into one through the TE30 mode synthesis section, at which point 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 circular waveguide TE31 mode 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] This invention has the following technical advantages: It proposes a broadband, efficient circular waveguide TE31 mode exciter. By combining a power divider, a twisted waveguide, and a gradient waveguide, it achieves conversion from a rectangular waveguide TE10 mode to a circular waveguide TE31 mode. The entire excitation process is performed in two steps, reducing losses during the conversion process and ensuring conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a three-dimensional structural 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 This is 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 Schematic diagram of the field distribution at the input and output ends of the three twisted waveguides in this embodiment;

[0025] Figure 6Graph showing the relationship between return loss and frequency at the input port of the circular waveguide TE31 mode exciter in the Q band according to this embodiment;

[0026] Figure 7 FIG. 4 is a diagram 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 will be further described below with reference to 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 splitter (21), a two-to-three power splitter (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 equal 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 equal 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, such as Figure 4 As shown, 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 opposite directions, 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 disclosed in application number "2024116521233" which can change the angle at any time, such as Figure 4 As shown, the twist waveguide includes an input rectangular waveguide, a "three-circular" twist waveguide, and an output rectangular waveguide. The dimensions of the input and output rectangular waveguides 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 angle between the three input and output rectangular waveguides is 90 degrees. The central axis of the center twist waveguide and the centerline of the narrow side of the waveguides on both sides are at a 45-degree angle. The central axis of the side twist waveguides and the centerline of the narrow side of the waveguides also have a 45-degree angle with the centerline of the narrow side of the waveguides, but in the opposite direction to the center 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 uniformly 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, while the wide side decreases linearly. The length is 34.51 mm, and the dimensions of the output port are a4*b4=17.07 mm*2.845 mm.

[0035] The dimensions of the standard TE30 mode rectangular waveguide section are a4*b4*c4=17.07mm*2.845mm*11.2mm, and are 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 in 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. 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 and high-efficiency circular waveguide TE31 mode exciter, characterized in that: It 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 includes a one-to-two power splitter (21), a two-to-three power splitter (22), three twisted waveguides (23), a TE30 mode synthesis section (24), and a TE30 mode transition section (25); wherein the one-to-two power splitter is used to divide the input TE10 mode into two equal paths and transmit the divided TE10 mode to the two-to-three power splitter; the two-to-three power splitter is used to divide the two input TE10 modes into three equal paths and input the three twisted waveguides respectively; the twisted waveguide is used to transmit the TE10 mode to the three twisted waveguides. To the TE30 mode synthesis section, the torsional waveguide located in the middle and the torsional waveguide located on the side respectively rotate the polarization direction of the input TE10 mode 90 degrees in opposite directions, 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 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 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 a 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 according to claim 1, characterized in that: The TE30 mode-circular waveguide TE31 mode conversion section comprises an axially cascaded rectangular waveguide conversion section (41) and a rectangular waveguide-circular waveguide conversion section (42); wherein the rectangular waveguide conversion section has a constant wide side and a linearly increasing narrow side; and the rectangular waveguide-circular waveguide conversion section uniformly and gradually transforms the rectangular output port of the rectangular waveguide conversion section to the input port of the TE31 mode circular waveguide section.

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

5. The broadband high-efficiency circular waveguide TE31 mode exciter according to claim 4, characterized in that: 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 three times the wide side size of the standard TE10 mode rectangular waveguide segment.

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