Double-working-condition coaxial input coupler suitable for high-power cyclotron amplifier

Abstract

A low-frequency-band input rectangular waveguide is located on the outer wall of the outer side of a four-groove coaxial resonant cavity, the low-frequency-band input rectangular waveguide and the four-groove coaxial resonant cavity are connected through a rectangular coupling hole in the four-groove coaxial resonant cavity, and a Bragg reflector is arranged on the low-frequency-band input rectangular waveguide; the microwave screening device is used for screening microwaves with different frequencies; the high-frequency-band input rectangular waveguide is also located on the outer wall of the outer side of the four-groove coaxial resonant cavity, is connected with the four-groove coaxial resonant cavity through a rectangular coupling hole, and is spaced from the low-frequency-band input rectangular waveguide by 180 degrees; the four-groove coaxial resonant cavity is connected with the output circular waveguide through four coupling slots uniformly arranged on the outer wall of the inner side, and the cut-off circular waveguide is centered with the axis of the output circular waveguide. Compared with an existing dual-working-condition input coupler, the dual-working-condition input coupler is simpler in structure, screening of microwaves with different frequencies is guaranteed only through the cut-off function of the Bragg reflector on the low-frequency-band rectangular waveguide, and efficient output from a high-frequency-band TE10 mode to a high-frequency-band TE02 mode is achieved.

Description

Technical Field

[0001] This invention belongs to the field of microwave and millimeter-wave vacuum electronic device technology, and relates to a dual-condition coaxial input coupler suitable for high-power cyclotron amplifiers. Background Technology

[0002] A cyclotron amplifier is a vacuum electronic device based on the electron cyclotron radiation mechanism. Operating on a fast-wavelength basis, the cyclotron amplifier modulates the velocity of the cyclotron electron beam using an input signal, causing the electron beam to cluster angularly. This ultimately achieves energy exchange between the electron beam and the working signal, i.e., power amplification of the working signal. Based on this working principle, the cyclotron amplifier overcomes the size concurrency effect of conventional vacuum amplifiers. This also ensures that the cyclotron amplifier has high power and wide bandwidth characteristics in the microwave, millimeter-wave, and even terahertz frequency bands, thus showing significant application prospects in high-resolution radar, high-speed communication, electronic warfare, and biomedicine. Consequently, it has attracted numerous researchers to participate in the research and development of cyclotron amplifiers, resulting in many outstanding research achievements. In a cyclotron amplifier, the input coupler is the device that feeds the working signal into the interaction structure.

[0003] Currently, some applications of cyclotron amplifiers require cross-frequency band operation, which necessitates providing multiple cyclotron amplifiers for different frequency bands to support the equipment. This deviates from the miniaturization and compactness development trend of cyclotron amplifiers and significantly increases costs. Therefore, a cyclotron amplifier capable of simultaneous multi-frequency band operation is needed to achieve both cross-frequency band operation and cost reduction. Consequently, the research demand for corresponding multi-band input couplers for such multi-frequency band cyclotron amplifiers has emerged. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a dual-condition coaxial input coupler suitable for high-power cyclotron amplifiers. This input coupler can operate in two different frequency bands, has a simplified structure, and ensures the selection of microwaves of different frequencies by only using the cutoff function of the Bragg reflector on the low-frequency rectangular waveguide, thereby achieving efficient output from the TE10 mode to the TE02 mode in the high-frequency band.

[0005] The solution to the technical problem of this invention is: a dual-condition coaxial input coupler suitable for high-power cyclotron amplifiers, comprising a cutoff circular waveguide, a Bragg reflector, a low-frequency input rectangular waveguide, a four-slot coaxial resonant cavity, a high-frequency input rectangular waveguide, and an output circular waveguide;

[0006] The low-frequency input rectangular waveguide is located on the outer wall of the four-slot coaxial resonator, and the two are connected through a rectangular coupling hole on the four-slot coaxial resonator. The low-frequency input rectangular waveguide is equipped with a Bragg reflector for filtering microwaves of different frequencies. The high-frequency input rectangular waveguide is also located on the outer wall of the four-slot coaxial resonator and is connected to the four-slot coaxial resonator through a rectangular coupling hole, and is spaced 180° from the low-frequency input rectangular waveguide. The four-slot coaxial resonator is connected to the output circular waveguide through four coupling slots evenly arranged on the inner outer wall, and the cutoff circular waveguide is aligned with the axis of the output circular waveguide.

[0007] Furthermore, when the input coupler operates in the low-frequency band, the operating mode is TE01 mode; when the input coupler operates in the high-frequency band, the operating mode is TE02 mode.

[0008] Furthermore, when high-frequency microwaves are fed into the high-frequency input rectangular waveguide by the Bragg reflector, they are transmitted through a four-slot coaxial resonant cavity to prevent the high-frequency microwaves from being transmitted to the low-frequency input rectangular waveguide, thereby ensuring that the high-frequency TE02 mode is coupled to the output circular waveguide for output.

[0009] Furthermore, of the four coupling slots, the included angle between any two adjacent coupling slots is 90°, and the included angle between the coupling slot and the rectangular coupling hole used to install the low-frequency input rectangular waveguide or the high-frequency input rectangular waveguide is 45°.

[0010] Furthermore, the waveguide diameter of the cutoff circular waveguide is 0.8-0.9 times the diameter of the output circular waveguide.

[0011] Furthermore, the distance between the Bragg reflector and the surface of the four-slot coaxial resonant cavity is 0.8–1.2 mm.

[0012] The beneficial effects of this invention compared to the prior art are:

[0013] (1) Compared with traditional input couplers, the present invention designs a dual-condition coaxial input coupler suitable for cyclotron amplifiers, which can operate in two different frequency bands, with operating modes being TE01 mode and TE02 mode respectively.

[0014] (2) Compared with the existing dual-condition input coupler, the structure of the present invention is more concise. It achieves the screening of microwaves of different frequencies by only using the cutoff function of the Bragg reflector on the low-frequency rectangular waveguide.

[0015] (3) In the low-frequency rectangular input waveguide, a Bragg reflector is used to prevent microwaves from being transmitted to the low-frequency input rectangular waveguide after passing through the coaxial resonant cavity when working in the high-frequency band, thereby ensuring that the high-frequency TE02 mode is coupled to the output circular waveguide for output. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the dual-condition coaxial input coupler of the present invention;

[0017] Figure 2 This is an axial sectional view of the dual-condition coaxial input coupler of the present invention;

[0018] Figure 3 This is a cross-sectional view of the dual-condition coaxial input coupler of the present invention;

[0019] Figure 4 This invention relates to the Bragg reflector in the dual-condition coaxial input coupler, and details the transmission parameters of the TE10 mode, as well as the electric field distribution of the low-frequency input rectangular waveguide during K / Ka band TE10 mode transmission.

[0020] Figure 5 The transmission parameters of the dual-condition coaxial input coupler of the present invention when it operates in the K-band, and the electric field distribution of the coupler when the TE01 mode is excited in the output waveguide;

[0021] Figure 6 The transmission parameters of the dual-condition coaxial input coupler of the present invention when it operates in the Ka band, and the electric field distribution of the coupler when the TE02 mode is excited in the output waveguide;

[0022] Figure 7 The output power curve of the dual-frequency dual-mode cyclotron amplifier corresponding to the dual-condition coaxial input coupler of the present invention is obtained by nonlinear numerical program calculation when the coupler is working normally. Detailed Implementation

[0023] A dual-condition coaxial input coupler suitable for high-power cyclotron amplifiers, such as Figure 1 As shown, it includes a cutoff circular waveguide 1, a Bragg reflector 2, a low-frequency input rectangular waveguide 3, a four-slot coaxial resonant cavity 4, a high-frequency input rectangular waveguide 5, and an output circular waveguide 6.

[0024] The low-frequency input rectangular waveguide 3 is located on the outer wall of the four-slot coaxial resonant cavity 4, and the two are connected through a rectangular coupling hole on the four-slot coaxial resonant cavity 4. The low-frequency input rectangular waveguide 3 is equipped with a Bragg reflector 2 for filtering microwaves of different frequencies. The high-frequency input rectangular waveguide 5 is also located on the outer wall of the four-slot coaxial resonant cavity 4, and is connected to the four-slot coaxial resonant cavity 4 through a rectangular coupling hole, and is spaced 180° from the low-frequency input rectangular waveguide 3. The four-slot coaxial resonant cavity 4 is connected to the output circular waveguide 6 through four coupling slots 7 evenly arranged on the inner outer wall. The cutoff circular waveguide 1 is aligned with the axis of the output circular waveguide 6.

[0025] When the input coupler operates in the low-frequency band, the operating mode is TE01 mode; when the input coupler operates in the high-frequency band, the operating mode is TE02 mode.

[0026] When high-frequency microwaves are fed into the high-frequency input rectangular waveguide 5, the Bragg reflector 2 transmits them through the four-slot coaxial resonant cavity 4, preventing the high-frequency microwaves from being transmitted to the low-frequency input rectangular waveguide 3. This ensures that the high-frequency TE02 mode is coupled to the output circular waveguide 6 for output.

[0027] The four coupling slots 7 have an angle of 90° between two adjacent coupling slots and an angle of 45° between the coupling slot and the rectangular coupling hole used to install the low-frequency input rectangular waveguide 3 or the high-frequency input rectangular waveguide 5.

[0028] The waveguide diameter of the cutoff circular waveguide 1 is 0.8-0.9 times the diameter of the output circular waveguide 6.

[0029] The distance between the Bragg reflector 2 and the surface of the four-slot coaxial resonant cavity 4 is 0.8–1.2 mm.

[0030] The invention will be further elaborated below with a design example of a coaxial input coupler in dual operating modes (K-band-TE01 mode; Ka-band-TE02 mode) and accompanying drawings.

[0031] Example 1

[0032] Input signal mode: TE10 mode

[0033] Operating Condition 1: Frequency Band - K-band, Frequency Range - 18.5GHz-20.5GHz, Operating Mode - TE01 Mode

[0034] Operating Condition 2: Frequency Band - Ka band, Frequency Range - 33.65GHz - 35.5GHz, Operating Mode - TE01 mode

[0035] Appendix Figure 1 This is a schematic diagram of the dual-condition coaxial input coupler of the present invention; Figure 2 This is an axial sectional view of the dual-condition coaxial input coupler of the present invention; Figure 3 This is a cross-sectional view of the dual-condition coaxial input coupler of the present invention.

[0036] The structure of this example includes an input rectangular waveguide 3 operating in the K-band and its Bragg reflector 2, an input rectangular waveguide 5 operating in the Ka-band, a four-slot coaxial resonant cavity 4 for coupling the TE01 mode and the TE02 mode, and a cutoff circular waveguide 1 and an output circular waveguide 6.

[0037] 1. K-band input rectangular coupler 3: adopts a standard rectangular waveguide (BJ-180), with a wide side dimension of 12.96mm, a narrow side dimension of 6.48mm, and a length of 14mm.

[0038] 2. Bragg reflector 2: The wide side is 15mm, the narrow side is 9mm, the thickness is 2mm, and the distance between it and the surface of the four-slot coaxial resonant cavity 4 is 1mm.

[0039] 3. Ka-band input rectangular coupler 5: adopts a standard rectangular waveguide (BJ-320), with a wide side dimension of 7.112mm, a narrow side dimension of 3.556mm, and a length of 13.5mm.

[0040] 4. Four-slot coaxial resonant cavity 4: The inner radius of the coaxial resonant cavity is 10.6 mm, the outer conductor radius is 13.5 mm, and the inner wall length of the cavity is 13 mm. Coaxial resonant cavity coupling slots 7: Width 2.5 mm, length 6 mm, thickness 5.265 mm, a total of 4 coupling slots, the first slot makes an angle of 45 degrees with the center of the rectangular waveguide, and the angle between adjacent coupling slots is 90 degrees.

[0041] 5. Cutoff circular waveguide 1: radius 9mm, length 10mm.

[0042] 6. Output circular waveguide 6: radius 10.1mm, length 60mm.

[0043] Figure 4 This figure shows the transmission parameters of the TE10 mode and the electric field distribution of the low-frequency input rectangular waveguide during TE10 mode transmission in the K / Ka bands, using a Bragg reflector in a dual-mode coaxial input coupler. As can be seen from the figure, in the K-band (18GHz-22.5GHz), the S21 parameter is almost zero, while the S11 parameter is less than -10dB. Simultaneously, the electric field distribution indicates that the TE10 mode successfully transmits to the other side of the waveguide. When operating in the Ka band (33GHz-36GHz), the TE01 mode is essentially cut off, with the S11 parameter greater than -1dB, and the S21 parameter less than -10dB across the entire frequency band, consistent with the electric field distribution. This demonstrates that the Bragg reflector can effectively cut off high-frequency microwaves, preventing microwave leakage at the low-frequency input rectangular waveguide.

[0044] Figure 5The images show the transmission parameters of the dual-mode coaxial input coupler operating in the K-band, and the electric field distribution of the coupler when the TE01 mode is excited in the output waveguide. Observing the images, it can be seen that when operating in the K-band, the S21 (TE10-TE01) parameter is greater than -3dB in the range of 18.5GHz to 20.5GHz, the S11 parameter is less than -10dB, and the S21 parameter for other modes is less than -25dB. Simultaneously, the electric field distribution diagram shows that the TE01 mode is successfully excited at the output port.

[0045] Figure 6 The images show the transmission parameters of the dual-mode coaxial input coupler operating in the Ka-band, and the electric field distribution of the coupler when the TE02 mode is excited in the output waveguide. Observing the images, it can be seen that when operating in the Ka-band, the S21 (TE10-TE02) parameter is greater than -3dB in the range of 33.65GHz to 35.5GHz, while the S21 parameters for S11 and other modes are less than -15dB, indicating successful suppression. Simultaneously, the electric field distribution diagram also shows the TE02 mode excited in the interleaved waveguide.

[0046] pass Figure 4 , Figure 5 , Figure 6 The data shows that the K / Ka band dual-mode coaxial input coupler designed in this example achieves the conversion from the rectangular waveguide TE10 mode to the cyclotron amplifier operating modes TE01 and TE02, whether in the K band from 18.5 GHz to 20.5 GHz or the Ka band from 33.65 GHz to 35.5 GHz. Furthermore, the S21 parameter is greater than -3 dB within this range, and reflection and parasitic modes are well suppressed.

[0047] Figure 7 When the dual-mode coaxial input coupler is working normally, the corresponding output power curve of the dual-frequency dual-mode cyclotron amplifier (obtained through nonlinear numerical program) shows that the peak output power of the K-band cyclotron amplifier is greater than 160kW, and the peak output power of the Ka-band cyclotron amplifier is greater than 200kW. This indicates that the dual-mode input coupler can be effectively applied to K-band-TE01 mode / Ka-band-TE02 mode dual-mode cyclotron amplifiers.

[0048] The above examples are only for the purpose of illustrating the present invention. The dual-condition coaxial input coupler proposed in this invention can also be applied to other frequency bands, and the specific size is determined by the corresponding frequency band and operating mode.

[0049] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

[0050] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A dual-condition coaxial input coupler suitable for high-power cyclotron amplifiers, characterized in that, It includes a cutoff circular waveguide (1), a Bragg reflector (2), a low-frequency input rectangular waveguide (3), a four-slot coaxial resonant cavity (4), a high-frequency input rectangular waveguide (5), and an output circular waveguide (6); The low-frequency input rectangular waveguide (3) is located on the outer wall of the four-slot coaxial resonant cavity (4). The two are connected through a rectangular coupling hole on the four-slot coaxial resonant cavity (4). The low-frequency input rectangular waveguide (3) is equipped with a Bragg reflector (2) for filtering microwaves of different frequencies. The high-frequency input rectangular waveguide (5) is also located on the outer wall of the four-slot coaxial resonant cavity (4). It is connected to the four-slot coaxial resonant cavity (4) through a rectangular coupling hole and is spaced 180° from the low-frequency input rectangular waveguide (3). The four-slot coaxial resonant cavity (4) is connected to the output circular waveguide (6) through four coupling gaps (7) evenly arranged on the inner outer wall. The cutoff circular waveguide (1) is aligned with the axis of the output circular waveguide (6).

2. The dual-condition coaxial input coupler for high-power cyclotron amplifiers according to claim 1, characterized in that, When the input coupler operates in the low-frequency band, the operating mode is TE01 mode; when the input coupler operates in the high-frequency band, the operating mode is TE02 mode.

3. A dual-condition coaxial input coupler suitable for high-power cyclotron amplifiers according to claim 2, characterized in that, When the high-frequency microwave is fed into the high-frequency input rectangular waveguide (5) by the Bragg reflector (2), it is transmitted through the four-slot coaxial resonant cavity (4) to prevent the high-frequency microwave from being transmitted to the low-frequency input rectangular waveguide (3), thereby ensuring that the high-frequency TE02 mode is coupled to the output circular waveguide (6) for output.

4. A dual-condition coaxial input coupler suitable for high-power cyclotron amplifiers according to claim 1, characterized in that, The four coupling slots (7) have an angle of 90° between two adjacent coupling slots and an angle of 45° between the coupling slot and the rectangular coupling hole used to install the low-frequency input rectangular waveguide (3) or the high-frequency input rectangular waveguide (5).

5. A dual-condition coaxial input coupler suitable for high-power cyclotron amplifiers according to claim 1, characterized in that, The waveguide diameter of the cutoff circular waveguide (1) is 0.8-0.9 times the diameter of the output circular waveguide (6).

6. A dual-condition coaxial input coupler suitable for high-power cyclotron amplifiers according to claim 1, characterized in that, The distance between the Bragg reflector (2) and the surface of the four-slot coaxial resonant cavity (4) is 0.8 to 1.2 mm.

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