Online high-power microwave coupling measurement device and method for circular waveguide

Abstract

The invention relates to a circular waveguide on-line high-power microwave coupling measurement device and method, belongs to the technical field of high-power microwave measurement, solves the technical problems of inaccurate measurement result and complex structure in microwave coupling measurement, and comprises a circular waveguide, a coupling waveguide, an auxiliary waveguide, a rectangular waveguide, a sealed waveguide coaxial converter and a sealed matching load. The coupling waveguide is located between the two circular waveguides, the center line coincides with the center line of the circular waveguide, and the coupling waveguide and the circular waveguide are in fillet transition. The coupling waveguide is provided with a coupling hole and is communicated with the rectangular waveguide of the auxiliary waveguide through the coupling hole. The circular waveguide is a transmission waveguide and is used for transmitting a high-power microwave signal; the coupling waveguide is used for sampling high-power microwave signals in the coupler main line and feeding the high-power microwave signals into the coupling hole. The method comprises the steps that in the microwave output channel, microwaves are coupled to the rectangular waveguide of the auxiliary waveguide through the coupling hole, then pass through the waveguide coaxial converter, the attenuator and the detector, and finally are transmitted to the oscilloscope through the coaxial cable.

Description

Technical Field

[0001] This invention belongs to the field of high-power microwave measurement technology, specifically relating to a circular waveguide online high-power microwave coupling measurement device and method. Background Technology

[0002] Relativistic backward wave tubes (RBTs) have attracted increasing attention from researchers in recent years due to their high power capacity, high output power, and repetitive frequency operation, making them promising candidates for various applications. The output microwave mode of a relativistic backward wave tube is TM. 01 To measure microwave output power, a TM model was established. 01 The online high-power microwave coupling measurement device is of great significance for measuring the output microwave power of relativistic backwave tubes.

[0003] Chinese invention patent CN105277816A discloses a high-power microwave coupling measurement device, such as... Figure 1 As shown, it includes a circular waveguide 1, an electrical probe 4, an insulating support structure 5, a secondary waveguide outer conductor 6, an RF coaxial connector 7, and a flange 8. The circular waveguide 1 is the main coupler line used to transmit high-power microwave signals; the electrical probe 4 is used to couple and sample the high-power microwave signals in the circular waveguide 1, and further feed them into the coaxial structure composed of the electrical probe 4 and the secondary waveguide outer conductor 6; the insulating support structure 5 supports the electrical probe 4 and maintains good vacuum sealing of the system during operation; the RF coaxial connector 7 is used to connect to an external RF cable; and the flange 8 is used to achieve a vacuum-sealed connection with the microwave source output port or radiation system.

[0004] During operation, the circular waveguide 1 is directly connected to the microwave output path of the high-power microwave source through flange 8, generating TM from the high-power microwave source. 01 The microwave signal is transmitted into the circular waveguide 1. As it continues to transmit, some of the microwave energy is coupled by the electrical probe 4 into the coaxial structure composed of the electrical probe 4 and the outer conductor 6 of the sub-waveguide. It is then transmitted through the coaxial RF cable via the RF coaxial connector 7. After further attenuation and detection, it is finally delivered to the oscilloscope in the shielded room via the coaxial cable.

[0005] When used for online high-power microwave coupling measurements of high-power microwave generators, the main problem with this structure is that, since the output of the coupling device is in the form of a coaxial SMA, the signal bandwidth of the coaxial output is very wide, which can easily lead to the entry of interference signals, resulting in inaccurate measurement results. Summary of the Invention

[0006] To overcome the shortcomings of inaccurate measurement results and complex structure in high-power microwave coupling measurement, this invention proposes a circular waveguide online high-power microwave coupling measurement device and method.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] A circular waveguide online high-power microwave coupling measurement device includes a circular waveguide, a coupling waveguide, a sub-waveguide rectangular waveguide, a sealed waveguide coaxial converter, and a sealed matching load.

[0009] The coupling waveguide is located between two circular waveguides, with its centerline coinciding with the centerline of the circular waveguides, and a rounded transition at the connection point. The coupling waveguide is equipped with a coupling aperture, through which it connects to the sub-waveguide rectangular waveguide.

[0010] The circular waveguide is a transmission waveguide used to transmit high-power microwave signals; the coupling waveguide is used to couple and sample a small amount of high-power microwave signals in the coupler main line and further feed them into the coupling aperture to prevent the coupling aperture from undergoing radio frequency breakdown.

[0011] During operation, the circular waveguide and the coupling waveguide together form the microwave output channel of the high-power microwave generator. A portion of the microwaves coupled through the coupling aperture to the rectangular waveguide of the secondary waveguide are then transmitted via a coaxial cable to the oscilloscope in the shielded room through a sealed waveguide coaxial converter. The sealed waveguide coaxial converter connects to external attenuators, detectors, or coaxial cables, providing a vacuum-sealed function. Because two microwave signals are coupled at the coupling aperture, one is used to measure microwave power, and the other is absorbed by a sealed matched load.

[0012] The aforementioned circular waveguide online high-power microwave coupling measurement device has an inner diameter of D1 = 50 mm and a rounded corner of Rx = 5 mm; an inner diameter of D2 = 78 mm and a length of d = 10.92 mm for the coupling waveguide; a coupling aperture diameter of d0 = 4 mm and a height of h = 0.8 mm; and a rectangular sub-waveguide with a wide side a = 22.86 mm and a narrow side b = 10.16 mm.

[0013] The aforementioned circular waveguide online high-power microwave coupling measurement device has an inner diameter of D1 = 30 mm and a rounded corner of Rx = 3.3 mm; an inner diameter of D2 = 49.2 mm and a length of d = 7.5 mm; a coupling aperture diameter of d0 = 4 mm and a height of h = 0.5 mm; and a sub-waveguide rectangular waveguide with a wide side of a = 15.8 mm and a narrow side of b = 7.9 mm.

[0014] A method for online high-power microwave coupling measurement of a circular waveguide includes the following steps:

[0015] In the microwave output channel of a high-power microwave generator, which is composed of a circular waveguide and a coupling waveguide, microwaves are coupled to the rectangular waveguide of the sub-waveguide through a coupling hole. Then, through a waveguide coaxial converter connected in a vacuum seal to an external attenuator, detector, or coaxial cable, the microwaves are finally transmitted via coaxial cable to an oscilloscope in a shielded room, achieving the transmission mode TM. 01Real-time online power measurement of high-power microwave circuits.

[0016] The beneficial effects of this invention are:

[0017] A circular waveguide online high-power microwave coupling measurement device can be directly integrated into the output waveguide of a high-power microwave generator, enabling measurement of microwaves in TM transmission mode. 01 Real-time online power measurement of high-power microwave circuits.

[0018] A circular waveguide online high-power microwave coupling measurement device is disclosed, wherein the coupling waveguide used for coupling high-power microwave energy has a coupling hole, which can be regarded as a section of circular waveguide that can cut off microwaves. Since the coupling hole is located at the maximum radius of the coupling cavity, the microwave electric field strength is small, which helps to prevent strong field breakdown at the coupling hole and improve the power capacity of the measurement device.

[0019] A circular waveguide online high-power microwave coupling measurement device is provided. The coupler uses a lower coupling degree to reduce subsequent attenuation links. Due to the reduction of intermediate links, the measurement uncertainty of the system is reduced.

[0020] A circular waveguide online high-power microwave coupling measurement device, through optimized design of the coupling cavity structure, achieves main path TM 01 The mode has ultra-low loss, with insertion loss of less than 0.01dB.

[0021] An online high-power microwave coupling measurement device using a circular waveguide is disclosed. The structural component for transmitting sampled microwave signals is a rectangular waveguide of the corresponding frequency band. The waveguide is directly connected to an attenuator, detector, or coaxial cable via a coaxial converter, simultaneously solving the system's vacuum sealing problem. Therefore, this measurement system exhibits strong operability and versatility. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a high-power microwave coupling measurement device in the prior art;

[0023] Figure 2 This is a schematic diagram of the structure of the circular waveguide online high-power microwave coupling measurement device according to Embodiment 1 of the present invention;

[0024] Figure 3 This is a front view of the circular waveguide online high-power microwave coupling measurement device according to Embodiment 1 of the present invention;

[0025] Figure 4 This is a perspective view of the circular waveguide online high-power microwave coupling measurement device according to Embodiment 1 of the present invention;

[0026] Figure 5 This is the coupling curve of the coupler in Embodiment 2 of the present invention;

[0027] Figure 6This refers to the insertion loss of the coupler in Embodiment 2 of the present invention;

[0028] Figure 7 This is the coupling curve of the coupler in Embodiment 3 of the present invention;

[0029] Figure 8 This refers to the insertion loss of the coupler in Embodiment 3 of the present invention.

[0030] Reference numerals: 1. Circular waveguide, 2. Coupled waveguide, 3. Coupled hole, 4. Electrical probe, 5. Insulating support structure, 6. Sub-waveguide outer conductor, 7. RF coaxial connector, 8. Flange, 9. Sub-waveguide rectangular waveguide, 10. Sealed waveguide coaxial converter, 11. Sealed matching load. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0032] Example 1

[0033] A circular waveguide online high-power microwave coupling measurement device, such as Figure 2 , 3 As shown in Figure 4, the system includes a circular waveguide 1, a coupling waveguide 2, a coupling aperture 3, a sub-waveguide rectangular waveguide 9, a sealed waveguide coaxial converter 10, and a sealed matching load 11. The circular waveguide 1 is the transmission waveguide used to transmit high-power microwave signals. The coupling waveguide 2 is used to couple and sample a small amount of the high-power microwave signal from the coupler's main line and further feed it into the coupling aperture. To prevent RF breakdown at the connection between the coupler's main line and the coupling waveguide 2, the circular waveguide is rounded. The output with a sealed waveguide coaxial converter can be directly connected to an external attenuator, detector, or coaxial cable, and has a vacuum-sealed function.

[0034] The main structural parameters of the online high-power microwave coupling measurement device are as follows: the inner diameter of the circular waveguide 1 is D1; ​​the inner diameter of the coupling waveguide 2 is D2; the inner diameter of the coupling hole 3 is d0; the wide side of the output standard rectangular waveguide is a, and the narrow side is b; the height of the coupling hole is h, and the rounded corner of the circular waveguide is Rx.

[0035] During operation, the circular waveguide 1 and the coupling waveguide 2 together form the microwave output channel of the high-power microwave generator. Due to the cutoff effect of the coupling waveguide 2, only a very small amount of microwave energy can be coupled through the coupling hole 3 to the sub-waveguide rectangular waveguide 9. Within the sub-waveguide rectangular waveguide 9, the energy is transmitted through a sealed waveguide coaxial converter, and after further attenuation and detection, it is finally delivered to the oscilloscope in the shielded room via a coaxial cable. Two microwave signals are coupled at the coupling hole, while the other microwave signal is absorbed by a sealed matched load.

[0036] Example 2

[0037] An embodiment of an online circular waveguide high-power microwave coupling measurement device of the present invention operates in the X-band, and its main structural parameters are as follows: D1 = 50mm, D2 = 78mm, d = 10.92mm, d0 = 4mm, h = 0.8mm, Rx = 5mm. The sub-waveguide rectangular waveguide 9 is a standard waveguide BJ100 for the corresponding frequency band, with a wide side dimension a = 22.86mm, a narrow side dimension b = 10.16mm, and a 5mm rounded corner. Within a bandwidth of 9.0-10.0GHz, the coupling degree of the online high-power microwave coupling measurement device with these structural parameters varies linearly between -71.8 and -68.9dB. At a power level of 5.0GW, the maximum RF field strength within the coupling waveguide is 465kV / cm, far lower than the vacuum RF breakdown field strength of 1.0MV / cm. The coupling curve of the coupler is shown below. Figure 5 As shown, the insertion loss curve of the coupler is as follows: Figure 6 As shown.

[0038] Example 3

[0039] Another embodiment of the circular waveguide online high-power microwave coupling measurement device of the present invention operates in the Ku band, and its main structural parameters are as follows: D1 = 30mm, D2 = 49.2mm, d = 7.5mm, d0 = 4mm, h = 0.5mm, Rx = 3.3mm. The sub-waveguide, rectangular waveguide 9, is a standard waveguide BJ140 for the corresponding frequency band, with a waveguide width dimension a = 15.8mm and a sub-waveguide dimension b = 7.9mm. Within a bandwidth of 14-16GHz, the coupling degree of the online high-power microwave coupling measurement device with these structural parameters varies linearly between -76.5 and -70.98dB. At a power level of 5.0GW, the maximum RF field strength within the coupling waveguide is 892kV / cm, which is lower than the vacuum RF breakdown field strength of 1.0MV / cm. The coupling curve of the coupler is shown below. Figure 7 As shown, the insertion loss curve of the coupler is as follows: Figure 8 As shown.

Claims

1. A circular waveguide online high-power microwave coupling measurement device, characterized in that, It includes a circular waveguide (1), a coupled waveguide (2), a sub-waveguide rectangular waveguide (9), a sealed waveguide coaxial converter (10), and a sealed matching load (11); in, The coupling waveguide (2) is located between two circular waveguides (1), with its centerline coinciding with the centerline of the circular waveguide (1) and rounded corners at the connection with the circular waveguide (1); the coupling waveguide (2) is provided with a coupling hole (3), and the coupling waveguide (2) is connected to the sub-waveguide rectangular waveguide (9) through the coupling hole (3); The circular waveguide (1) is a transmission waveguide used to transmit high-power microwave signals; the coupling waveguide (2) is used to couple and sample the high-power microwave signals in the coupler main line and feed them into the coupling aperture (3); During operation, the circular waveguide (1) and the coupled waveguide (2) together constitute the microwave output channel of the high-power microwave generator; Microwaves coupled through coupling hole (3) to the sub-waveguide rectangular waveguide (9) are transmitted to the oscilloscope in the shielded room by coaxial cable through waveguide coaxial converter; the sealed waveguide coaxial converter is connected to external attenuator, detector or coaxial cable and has vacuum sealing function.

2. The microwave coupling measurement device according to claim 1, characterized in that, The inner diameter of the circular waveguide (1) is D1 = 50 mm, and the rounded corners of the circular waveguide (1) are Rx = 5 mm; the inner diameter of the coupling waveguide (2) is D2 = 78 mm, and the length is d = 10.92 mm. The coupling hole (3) has a diameter d0 = 4 mm and a height h = 0.8 mm; the sub-waveguide rectangular waveguide (9) has a wide side a = 22.86 mm and a narrow side b = 10.16 mm.

3. The microwave coupling measurement device according to claim 1, characterized in that, The inner diameter of the circular waveguide (1) is D1 = 30 mm, and the rounded corner of the circular waveguide (1) is Rx = 3.3 mm; the inner diameter of the coupling waveguide (2) is D2 = 49.2 mm, and the length is d = 7.5 mm. The coupling hole (3) has a diameter d0 = 4 mm and a height h = 0.5 mm; the sub-waveguide rectangular waveguide (9) has a wide side a = 15.8 mm and a narrow side b = 7.9 mm.

4. A method for online high-power microwave coupling measurement using a circular waveguide, characterized in that, Includes the following steps: In the microwave output channel of the high-power microwave generator, which is jointly formed by the circular waveguide (1) and the coupling waveguide (2), microwaves are coupled to the sub-waveguide rectangular waveguide (9) through the coupling hole (3), and then connected to the external attenuator and detector through the vacuum-sealed waveguide coaxial converter. Finally, the microwaves are transmitted to the oscilloscope in the shielded room through the coaxial cable, realizing the transmission mode TM. 01 The high-power microwave online power is measured in real time; because two microwave signals are coupled at the coupling hole, one is used to measure microwave power, and the other microwave signal is absorbed by a sealed matching load.

Images