A toroidal high power microwave pulse compressor

Abstract

The application discloses a kind of annular high-power microwave pulse compressors, belong to high-power microwave field.It includes directional coupler and waveguide transmission line;Directional coupler includes four ports, waveguide transmission line includes input port and output port;The first port of directional coupler is used to receive microwave signal from outside, the second port is used to output microwave signal compressed after waveguide transmission line and part of microwave signal from outside to external load;Third port and fourth port are connected with the input port and output port of waveguide transmission line respectively;The length of waveguide transmission line is set to make the microwave signal output from the first port to the third port and the microwave signal output from the fourth port to the third port have the same phase.The application uses traveling wave energy storage, has the characteristics of simple structure, high power capacity, has good power gain, and can provide output pulse with flat top waveform.

Description

Technical Field

[0001] The present invention belongs to the field of high-power microwaves, and in particular relates to a ring-shaped high-power microwave pulse compressor. Background Art

[0002] Pulse compression is a technology for generating high-power microwaves. It works by inputting microwave pulses into an energy storage device and then rapidly extracting the microwave energy from the device, increasing the power of the input microwave pulses by several or even dozens of times, thereby achieving high-power microwave pulse output. Currently, pulse compressors are widely used in accelerators to compensate for the insufficient peak power output of klystron tubes.

[0003] The first pulse compressor was the SLED (SLAC Energy Doubler) from the SLAC National Accelerator Laboratory. It consisted of a 3dB coupler and two resonant cavities with identical quality factors. A klystron simultaneously charged the two identical energy storage cavities through a four-port 3dB coupler, extracting the stored energy by phase-inverting the input pulses. Many subsequent pulse compressors, such as the SLED-II, the BOC (Barrel Shaped Open Cavity), and the spherical resonant cavity, have been adapted from this model.

[0004] In the field of high-power microwave (HPM) pulse compression, the technology of obtaining flat-top output (i.e., a waveform with small fluctuations at the top of the pulse and uniform energy distribution) is crucial for applications such as particle accelerators and directed energy weapons.

[0005] Traditional pulse compression techniques for achieving flat-top output include SLED-II, whose basic structure still consists of a 3 dB coupler and two energy storage units. To generate square wave pulses, the SLED-II pulse compressor uses a delay line as its energy storage unit. However, the excessive fill time results in a very long delay line. The SLED-II pulse compressor designed at CERN at 30 GHz produces a flat-top output of 70 ns, but its length is also 9 meters.

[0006] Pulse compression technologies that can also achieve flat-top outputs include amplitude-modulated cavity chain pulse compression technology. Taking CERN's SLEDX as an example, a total of 18 resonant cavities with a total length of 7.2m are required. The overall system complexity is high, and the cost and maintenance requirements are also correspondingly increased. Tsinghua University proposed using dual-polarization mode couplers and spherical resonant cavities to replace the resonant cavities in the original amplitude-modulated cavity chain pulse compressor, but there are still problems such as the complex system and the high processing precision requirements of the spherical cavity, resulting in high system costs. Summary of the Invention

[0007] In order to solve the problems in the prior art, the present invention proposes a ring-shaped high-power microwave pulse compressor.

[0008] The technical solution adopted in the present invention is as follows:

[0009] In a first aspect, the present invention discloses a ring-shaped high-power microwave pulse compressor, comprising a directional coupler and a waveguide transmission line;

[0010] The directional coupler includes four ports, the first port is an input port, the second port is a through port, the third port is a coupled port, and the fourth port is an isolated port. The waveguide transmission line includes an input port and an output port. The first port of the directional coupler is used to receive a microwave signal from the outside, and the second port is used to output the microwave signal compressed by the waveguide transmission line to an external load. The third port and the fourth port are connected to the input port and the output port of the waveguide transmission line, respectively.

[0011] The directional coupler splits the microwave signal into two equal parts, and the two divided microwave signals are output from the second port and the third port, respectively. The phase difference between the microwave signals output from the second port and the third port is 90 degrees. The microwave signal output from the third port is transmitted through the waveguide transmission line and then returns to the directional coupler from the fourth port. It is then split into two equal parts again and output from the second port and the third port, respectively.

[0012] The length of the waveguide transmission line is set so that the microwave signal output from the first port to the third port is in phase with the microwave signal output from the fourth port to the third port, and the microwave signals are linearly superimposed at the third port; the microwave signal output from the fourth port to the second port is in phase with the microwave signal output from the first port to the second port.

[0013] In a second aspect, the present invention discloses a microwave pulse compression method using the annular high-power microwave pulse compressor, comprising the following steps:

[0014] The directional coupler receives a microwave signal from the outside through the first port and splits it into two equal parts. The two divided microwave signals are output from the second port and the third port respectively, and the phase difference between the microwave signals output from the second port and the third port is 90°.

[0015] The microwave signal output from the third port is transmitted through the waveguide transmission line and then returns to the directional coupler from the fourth port, where it is split into two equal parts again. After being split into two equal parts, it is output from the second port and the third port respectively. At this time, the microwave signal output from the first port to the third port has the same phase as the microwave signal transmitted from the fourth port to the third port, so the microwave signals are linearly superimposed at the third port, while the signal output from the fourth port to the second port has an opposite phase to the microwave signal output from the first port to the second port, so the microwave energy output from the second port is weakened. The above linear superposition process is repeated continuously, and the amplitude of the microwave signal in the waveguide transmission line gradually increases. When the amplitude of the microwave signal output from the second port is equal to the amplitude of the microwave signal from the outside received by the first port, the compressor achieves a steady state, and the microwave signal stores energy in the waveguide transmission line in a traveling wave state.

[0016] When energy extraction is required, the phase of the externally input microwave signal is flipped 180°. At the moment of phase flipping, the microwave signal output from the first port to the second port has the same phase as the microwave signal output from the fourth port to the second port when the compressor is in a steady state. The microwave signal achieves instantaneous power doubling in the second port, completing microwave pulse compression.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The annular pulse compression system of the present invention uses a waveguide transmission line for energy storage, overcoming the current situation in which the output power of the existing pulse compression system decays exponentially, while ensuring a certain power gain and obtaining a wide flat-top output.

[0019] (2) The present invention is almost entirely made up of rectangular waveguides. Compared with other high-power microwave pulse compression technologies that can produce flat-top output, it has a smaller size, simpler structure, lower processing difficulty, lower cost, and lower maintenance difficulty.

[0020] (3) The present invention uses a waveguide transmission line for traveling wave energy storage, overcoming the low power capacity of the existing pulse compression system using standing wave energy storage and having a higher power capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of a ring-shaped high-power microwave pulse compressor in an embodiment of the present invention;

[0022] Figure 2 Schematic diagram of a directional coupler in an embodiment of the present invention;

[0023] Figure 3 This is a power gain curve diagram of the annular high-power microwave pulse compressor according to an embodiment of the present invention;

[0024] Figure 4This is the electric field diagram of the annular high-power microwave pulse compressor according to an embodiment of the present invention.

[0025] Reference numerals in the figure: 1-directional coupler; 2-waveguide transmission line. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0027] It should be noted that all directional indications (such as up, down, left, right, front, and back) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0028] In addition, the terms "first," "second," and so on, used in this disclosure are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referenced. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this disclosure, "plurality" means at least two, such as two or three, unless otherwise specifically defined.

[0029] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; it can mean mechanical connection, electrical connection, physical connection, or wireless communication connection; it can mean direct connection or indirect connection through an intermediate medium; it can mean internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] The present invention will be further described in detail below with reference to the accompanying drawings.

[0031] In response to the current problems with pulse compression technology that produces flat-top output, the present invention proposes an annular high-power microwave pulse compressor. The present invention aims to ensure a higher power gain while obtaining a flat-top output with a larger width, and to simplify the structure of the annular high-power microwave pulse compressor to make it simple and compact, reduce processing difficulty, and reduce costs.

[0032] like Figure 1As shown, the ring-shaped high-power microwave pulse compressor of the present invention includes a directional coupler 1 and a waveguide transmission line 2.

[0033] Among them, the directional coupler 1 includes four ports, the first port is an input port, the second port is a through port, the third port is a coupled port, and the fourth port is an isolated port; the waveguide transmission line 2 includes an input port and an output port; the first port of the directional coupler 1 is used to receive a microwave signal from the outside, and the second port of the directional coupler 1 is used to output the microwave signal compressed by the waveguide transmission line 2 and part of the microwave signal from the outside to the external load; the third port and the fourth port of the directional coupler 1 are respectively connected to the input port and the output port of the waveguide transmission line 2.

[0034] Directional coupler 1 splits the microwave signal into two equal parts, and the two divided microwave signals are output from the second port and the third port, respectively. The phase difference between the microwave signals output from the second port and the third port is 90°. The microwave signal output from the third port is transmitted through the waveguide transmission line and returns to the directional coupler from the fourth port, where it is split into two again and then output from the second port and the third port, respectively.

[0035] The length of the waveguide transmission line 2 is set so that the microwave signal output from the first port to the third port is in phase with the microwave signal output from the fourth port to the third port, and the microwave signals are linearly superimposed at the third port; the microwave signal output from the fourth port to the second port is in phase with the microwave signal output from the first port to the second port.

[0036] In a specific embodiment of the present invention, the directional coupler 1 is a 3dB coupler.

[0037] Specifically, the directional coupler 1 includes a first main transmission line, a second main transmission line and a branch transmission line. The first main transmission line and the second main transmission line are parallel to each other. The first main transmission line connects the first port and the second port, and the second main transmission line connects the third port and the fourth port. The branch transmission line is vertically connected between the first main transmission line and the second main transmission line to achieve 3dB power coupling.

[0038] In a preferred embodiment of the present invention, the first main transmission line and the second main transmission line are both rectangular waveguides, and the two rectangular waveguides are provided with six grooves for reducing reflection of the directional coupler and enhancing the directivity of the directional coupler.

[0039] The six grooves can be two large grooves and four small grooves, and each rectangular waveguide is provided with one large groove and two small grooves. The large groove is provided in the middle of the wide wall of the rectangular waveguide, and the two small grooves are also provided on the wide wall of the rectangular waveguide, and are provided on both sides of the large groove and symmetrically relative to the large groove. Both the large groove and the small groove are rectangular grooves, the width of the large groove is greater than the width of the small groove, and the depth of the large groove is less than the depth of the small groove.

[0040] In the present invention, the waveguide transmission line is formed by connecting multiple sections of rectangular waveguides end to end, and adjacent sections of rectangular waveguides are perpendicular to each other. The outer edge of the right-angle turning point of the waveguide transmission line is chamfered to ensure smooth transmission of microwave signals and reduce reflection of microwave signals at the turning point.

[0041] For the present invention, the chamfer can be a 45° bevel or a circular arc, but the ultimate goal is to ensure smooth transmission of microwave signals and reduce reflection of microwave signals at the turning point.

[0042] Furthermore, the length of the waveguide transmission line 2 of the present invention also affects the duration of the flat-top output. The longer the waveguide transmission line 2, the longer the flat-top output. Therefore, according to the art, while ensuring that the length of the waveguide transmission line 2 ensures that the microwave signal output from the first port to the third port is in phase with the microwave signal output from the fourth port to the third port, it is reasonable to choose a longer waveguide transmission line 2 to extend the duration of the flat-top output.

[0043] In order to more clearly illustrate the purpose, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] This embodiment is a complete S-band (2.849 GHz) annular high-power microwave pulse compressor, that is, the annular high-power microwave pulse compressor of this embodiment is used to perform pulse compression on a 2.849 GHz microwave signal, wherein the microwave signal is a sine wave.

[0045] like Figure 1 As shown, the annular high-power microwave pulse compressor of the present invention includes a directional coupler 1 and a waveguide transmission line 2. The standard rectangular waveguide in the directional coupler 1 and the waveguide transmission line 2 adopts BJ32 (a=72.14mm, b=34.04mm).

[0046] The directional coupler 1 includes four rectangular ports, and the waveguide transmission line 2 includes two rectangular ports, namely, an input port and an output port; the first port and the second port of the directional coupler 1 are used to receive an external microwave signal and output a microwave signal, respectively, and the third port and the fourth port of the directional coupler 1 are connected to the two ports of the waveguide transmission line 2, namely, the input port and the output port of the waveguide transmission line 2, respectively.

[0047] like Figure 2 As shown, the directional coupler is a 3dB coupler with rectangular grooves on its sides to enhance its directivity and reduce reflections. The width and depth of the grooves affect the coupler's parameters, and thus the reflection and gain of the entire pulse compressor. Therefore, the groove parameters need to be optimized to achieve this goal.

[0048] In this embodiment, the large groove and the small groove are both square grooves, wherein the large groove has a width of 17.66 mm and a depth of 3.1 mm, the small groove has a width of 3 mm and a depth of 7.23 mm, and the four small grooves have the same size.

[0049] The waveguide transmission line 2 is composed of multiple sections of rectangular waveguides. The total length of the waveguide transmission line 2 is 18m. The multiple sections of rectangular waveguides are connected in an "S" shape. A 45° angle is set at the turning point of the waveguide to ensure smooth transmission of the microwave signal and reduce the reflection of the microwave signal at the turning point.

[0050] The entire annular microwave pulse compressor occupies an area of ​​about 3.4m 2 The ring-shaped microwave pulse compressor is approximately 2 meters long, 1.62 meters wide, and only 34.04 mm high. This makes it compact and easy to assemble and move. The entire ring-shaped microwave pulse compressor is made up almost entirely of rectangular waveguides, resulting in a relatively low cost.

[0051] In a specific embodiment of the present invention, the present invention further provides a microwave pulse compression method using the annular high-power microwave pulse compressor, comprising the following steps:

[0052] The first port of the directional coupler receives a microwave signal from the outside. The directional coupler splits the input microwave signal into two equal parts. One part of the split microwave signal is output through the second port of the directional coupler, and the other part of the microwave signal is input into the waveguide transmission line through the third port of the directional coupler. The phase difference between the microwave signals at the second and third ports of the directional coupler is 90°.

[0053] After a period of time, the microwave signal entering the waveguide transmission line is transmitted to the fourth port of the directional coupler. The microwave signal then returns to the directional coupler through the fourth port. The directional coupler then splits the microwave signal input from the fourth port into two equal parts. One portion of the split signal is output through the second port, while the other portion is input into the waveguide transmission line through the third port. At this point, the microwave signal input from the first port of the directional coupler to the third port is in phase with the microwave signal transmitted from the fourth port to the third port. Therefore, the microwave signals are linearly superimposed at the third port. The microwave signal output from the fourth port to the second port is in phase with the microwave signal output from the first port to the second port, resulting in a weakened microwave energy output from the second port. This linear superposition process repeats itself, gradually increasing the amplitude of the microwave signal within the waveguide transmission line. When the amplitude of the microwave signal output from the second port equals the amplitude of the external microwave signal received at the first port, the compressor reaches a steady state, and the microwave signal stores energy within the waveguide transmission line as a traveling wave.

[0054] When energy extraction is required, the phase of the external microwave signal is flipped 180°. At the moment of the phase flip, the microwave signal output from the first port to the second port becomes identical in phase with the microwave signal output from the fourth port to the second port when the compressor is in steady state. This instantaneous power doubling of the microwave signal occurs within the second port, completing microwave pulse compression. Furthermore, due to the characteristics of the waveguide transmission line, the output pulse waveform exhibits a flat-top characteristic.

[0055] In the present invention, the directional coupler divides the externally input microwave signal into two equal parts, outputs one part of the divided microwave signal to the second port, and outputs the other part of the microwave signal to the third port; at this time, the phase of the microwave signal output to the second port is equal to the phase of the externally input microwave signal, and the phase of the microwave signal output to the third port is the phase of the externally input microwave signal minus 90°.

[0056] The directional coupler splits the microwave signal input from the fourth port into two equal parts, outputting one part of the microwave signal to the second port and the other part to the third port. At this time, the phase of the microwave signal output to the second port is the phase of the microwave signal input from the fourth port minus 90°, and the phase of the microwave signal output to the third port is equal to the phase of the microwave signal input from the fourth port.

[0057] In a preferred embodiment of the present invention, flipping the phase of the externally input microwave signal by 180° means adjusting the phase of the externally input microwave signal to the original phase minus 180°.

[0058] The embodiment of the ring-shaped high-power microwave pulse compressor of the present invention has the following effects: Figure 3 and Figure 4As shown in the figure, when the pulse width of the input microwave signal is 2000ns and the phase is reversed at 1800ns, the power gain of the ring-shaped high-power microwave pulse compressor is about 5.75, and the output signal has a flat-top output of about 80ns. Figure 4 As shown, when the input power is 0.5W, the maximum electric field in the ring resonator is 1675V / m. When the breakdown threshold is 300kV / cm, the pulse compressor's power capacity can reach 160MW. This shows that the ring-shaped high-power microwave pulse compressor of the present invention not only ensures high power gain, but also achieves a wide flat-top output, while also ensuring high power capacity.

[0059] The beneficial effect of this invention is that the annular high-power microwave pulse compressor can significantly increase the output microwave pulse power, with peak power exceeding 7.6dB. The integration of a directional coupler with a waveguide transmission line can enhance the overall performance of the high-power microwave pulse compressor, providing output pulses with a flat-top waveform while maintaining good power gain.

[0060] The present invention utilizes a ring-shaped pulse compressor, which achieves excellent power gain while also providing output pulses with a flat-top waveform. Compared to other high-power microwave pulse compression technologies that produce flat-top outputs, the compressor of the present invention is smaller, simpler in structure, easier to manufacture, and less expensive and requires less maintenance. Furthermore, the present invention utilizes traveling-wave energy storage, resulting in a higher power capacity than pulse compressors using standing-wave energy storage.

[0061] The above-described embodiments merely illustrate several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. Persons skilled in the art will readily appreciate that variations and modifications may be made without departing from the scope of the present invention, all of which fall within the scope of protection of the present invention.

Claims

1. A ring-shaped high-power microwave pulse compressor, characterized in that: including directional couplers and waveguide transmission lines; The directional coupler includes four ports, the first port is an input port, the second port is a through port, the third port is a coupled port, and the fourth port is an isolated port. The waveguide transmission line includes an input port and an output port. The first port of the directional coupler is used to receive a microwave signal from the outside, and the second port is used to output the microwave signal compressed by the waveguide transmission line to an external load; the third port and the fourth port are connected to the input port and the output port of the waveguide transmission line respectively; The directional coupler splits the microwave signal into two equal parts, and the two divided microwave signals are output from the second port and the third port, respectively. The phase difference between the microwave signals output from the second port and the third port is 90 degrees. The microwave signal output from the third port is transmitted through the waveguide transmission line and then returns to the directional coupler from the fourth port. It is then split into two equal parts again and output from the second port and the third port, respectively. The length of the waveguide transmission line is set so that the microwave signal output from the first port to the third port is in phase with the microwave signal output from the fourth port to the third port, and the microwave signals are linearly superimposed at the third port; the microwave signal output from the fourth port to the second port is in phase with the microwave signal output from the first port to the second port.

2. The annular high-power microwave pulse compressor according to claim 1, characterized in that: The directional coupler is a 3dB coupler.

3. The annular high-power microwave pulse compressor according to claim 1, characterized in that: The directional coupler includes a first main transmission line, a second main transmission line and a branch transmission line. The first main transmission line and the second main transmission line are parallel to each other. The first main transmission line connects the first port and the second port, and the second main transmission line connects the third port and the fourth port. The branch transmission line is vertically connected between the first main transmission line and the second main transmission line to achieve 3dB power coupling.

4. The annular high-power microwave pulse compressor according to claim 3, characterized in that: The first main transmission line and the second main transmission line are both rectangular waveguides. Six grooves are provided on the two rectangular waveguides to reduce reflection of the directional coupler and enhance the directivity of the directional coupler.

5. The annular high-power microwave pulse compressor according to claim 4, characterized in that: The six grooves include two first grooves and four second grooves. Each rectangular waveguide is provided with one first groove and two second grooves. The first groove is provided in the middle position of the wide wall surface of the rectangular waveguide. The two second grooves are also provided on the wide wall surface of the rectangular waveguide and are provided on both sides of the first groove and symmetrically relative to the first groove. The first groove and the second groove are both rectangular grooves, the width of the first groove is greater than the width of the second groove, and the depth of the first groove is less than the depth of the second groove.

6. The annular high-power microwave pulse compressor according to claim 1, characterized in that: The waveguide transmission line is formed by connecting multiple sections of rectangular waveguides end to end, with adjacent sections of rectangular waveguides perpendicular to each other. The outer edge of the right-angle turning point of the waveguide transmission line is chamfered to ensure smooth transmission of microwave signals and reduce reflection of microwave signals at the turning point.

7. A microwave pulse compression method using the annular high-power microwave pulse compressor according to claim 1, characterized in that: The following steps are involved: The directional coupler receives a microwave signal from the outside through the first port and splits it into two equal parts. The two divided microwave signals are output from the second port and the third port respectively, and the phase difference between the microwave signals output from the second port and the third port is 90°. The microwave signal output from the third port is transmitted through the waveguide transmission line and then returns to the directional coupler from the fourth port, where it is split into two equal parts again. After being split into two equal parts, it is output from the second port and the third port respectively. At this time, the microwave signal output from the first port to the third port has the same phase as the microwave signal transmitted from the fourth port to the third port, so the microwave signals are linearly superimposed at the third port, while the signal output from the fourth port to the second port has an opposite phase to the microwave signal output from the first port to the second port, so the microwave energy output from the second port is weakened. The above linear superposition process is repeated continuously, and the amplitude of the microwave signal in the waveguide transmission line gradually increases. When the amplitude of the microwave signal output from the second port is equal to the amplitude of the microwave signal from the outside received by the first port, the compressor achieves a steady state, and the microwave signal stores energy in the waveguide transmission line in a traveling wave state. When energy extraction is required, the phase of the externally input microwave signal is flipped 180°. At the moment of phase flipping, the microwave signal output from the first port to the second port has the same phase as the microwave signal output from the fourth port to the second port when the compressor is in a steady state. The microwave signal achieves instantaneous power doubling in the second port, completing microwave pulse compression.

8. The microwave pulse compression method according to claim 7, characterized in that: The directional coupler splits the external microwave signal into two equal parts, outputting one part of the split microwave signal to the second port and the other part to the third port. At this time, the phase of the microwave signal output to the second port is equal to the phase of the external microwave signal, and the phase of the microwave signal output to the third port is the phase of the external microwave signal minus 90°.

9. The microwave pulse compression method according to claim 7, characterized in that: The directional coupler splits the microwave signal input from the fourth port into two equal parts, outputting one part of the microwave signal to the second port and the other part to the third port. At this time, the phase of the microwave signal output to the second port is the phase of the microwave signal input from the fourth port minus 90°, and the phase of the microwave signal output to the third port is equal to the phase of the microwave signal input from the fourth port.

10. The microwave pulse compression method according to claim 7, characterized in that: Flipping the phase of the externally input microwave signal by 180° means adjusting the phase of the externally input microwave signal to the original phase minus 180°.

Images