High-efficiency microwave pulse compressor

Abstract

The invention discloses a high-efficiency microwave pulse compressor, which belongs to the technical field of high-power microwaves and comprises a first mode converter, a first transition structure, a dispersion structure, a second transition structure, a second mode converter, a radiation structure and the like. The components are sequentially connected in series for use, and the first mode converter converts a mode of input microwave pulse into a working mode of a dispersion structure; the microwave pulse after mode conversion is efficiently transmitted to the dispersion structure through the transition structure, the dispersion structure compresses the input frequency modulation pulse, and the second transition structure and the second mode converter convert the compressed high-power short pulse into a microwave mode required by radiation; and the radiation structure directionally radiates the high-power short microwave pulse to a space target. The high-efficiency microwave pulse compressor has the advantages of being simple in system, compact in structure and large in power capacity, has good application prospects in the aspects of microwave source arraying, modularization and the like, and is expected to improve the performance of a high-power microwave system.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-power microwave, and relates to a high-efficiency microwave pulse compressor. Background Art

[0002] Nowadays, countries around the world are accelerating the development of equipment systems towards unmanned and intelligent directions. Electronic information devices, systems, and networks are becoming increasingly rich, and the electromagnetic environment is getting more and more complex. In the face of the competition for electromagnetic dominance in the future complex electromagnetic environment, high-power microwave sources with wide-spectrum characteristics are one of the key means to achieve strategic initiative. The technologies for generating wide-spectrum high-power microwaves mainly include frequency tuning, superradiance, and pulse compression, etc. Among them, pulse compression is to compress a low-power long microwave pulse into a high-power short microwave pulse, and the power gain can reach several times to dozens of times. Due to the advantages of modularization and arrayation, microwave pulse compression has become a potential high-power microwave generation technology.

[0003] Pulse compression technology has been widely used in the field of accelerators to achieve the acceleration of charged particles. With the development of technology, its application in the field of high-power microwaves is increasing. Here are several typical pulse compression technologies. In 2015, researchers proposed a five-fold helically corrugated waveguide and applied it to passive pulse compression research. In the experiment, the microwave pulse width of 80 ns was compressed to 1.6 ns, and the corresponding energy efficiency was 66.3%. The microwave pulse compression gain in the X-band was about 14 dB (L. Zhang et al., Experimental Study of Microwave Pulse Compression Using a Five-Fold Helically Corrugated Waveguide[J], IEEE Transactions on Microwave Theory and Techniques, vol. 63, no. 3, pp. 1090-1096, March 2015). In 2018, based on the principle of energy storage resonant cavity, on a two-speed klystron high-power platform, the design of a compact two-stage pulse compressor was completed. The power gain of this pulse compressor was as high as 13 dB, breaking through the limitation that the gain limit of the passive pulse compressor is 9 (Wang Ping. Research on a New High-Power Microwave Pulse Compressor[D]. Beijing: Tsinghua University, 2018.). In 2023, researchers based on a microwave chaotic cavity and carried out pulse compression according to the time-reversal model. The compression gain was theoretically increased by 6 dB - 12 dB, and the experimental results were in the range of 5 dB - 8.5 dB (Lu Xicheng. Research on Time-Reversal Pulse Compression Technology of Microwave Chaotic Cavity and Its Applications[D]. Xi'an: Xidian University, 2023).

[0004] At present, various pulse compression methods have received a great deal of attention and research. Methods such as energy storage resonators and energy multipliers have high power gains, but there are problems such as relatively complex systems and limited power capacity. The pulse compression method based on a microwave chaotic cavity has characteristics such as high gain and simple structure, but faces the problems of large volume and low energy transmission efficiency. The research results show that due to reasons such as energy loss in the pulse compression system, the efficiency of pulse compressors is usually lower than 60%. Therefore, it is necessary to explore a higher-efficiency microwave pulse compressor to meet the application requirements in the field of high-power microwaves. Summary of the Invention (I) Summary of the Invention

[0006] The object of the present invention is to develop a high-efficiency microwave pulse compressor to achieve high-gain pulse compression, efficiently increase the peak power of microwave pulses, and thus enhance the power of a wide-spectrum high-power microwave source.

[0007] (II) Technical Solution

[0008] In order to achieve the above object of the invention, the technical solution adopted by the present invention is as follows:

[0009] A high-efficiency microwave pulse compressor is designed, and the main components include a first mode converter, a first transition structure, a dispersion structure, a second transition structure, a second mode converter, and a radiation structure. The above components are used in series in sequence. The first mode converter converts the mode of the input microwave pulse into the working mode of the dispersion structure; the first transition structure is used to connect the mode converter and the dispersion structure to achieve efficient transmission of microwave pulses and avoid the generation of reflection and non-working modes; the dispersion structure compresses the input frequency-modulated pulse to obtain a compressed microwave pulse with high gain; the subsequent second transition structure and second mode converter convert the mode of the compressed high-power microwave pulse into the microwave mode of radiation again; finally, the radiation structure radiates the high-power microwave pulse to the spatial target. Among them, the dispersion structure is the core and the key to achieving high-gain and high-efficiency microwave pulse compression.

[0010] Furthermore, a hollow waveguide structure is used to design the components of the pulse compressor such as the mode converter, transition structure, dispersion structure, and radiation structure to improve the power capacity of the system.

[0011] The dispersion structure can adopt a spiral corrugated waveguide, and the group velocity of its coupled mode changes rapidly with frequency and is far from the cut-off region, which is conducive to achieving high-gain microwave pulse compression. This structure can be expressed by the following formula:

[0012]

[0013] where r 0 is the average radius of the spiral corrugated waveguide, r 0Selected in the range of 0.42λ to 0.52λ; r 1 is the corrugation amplitude, r 1 Selected in the range of 0.34λ to 0.45λ; m B is the angular wave number, determined by the angular selection condition; k B = 2π / d is the axial wave number, which needs to satisfy the Bragg condition; d is the axial period length, and d satisfies the range of 0.75λ to 0.95λ. λ is the microwave wavelength.

[0014] The radiation structure can adopt a horn feed with a variable flare angle and a smooth inner wall to meet the requirements of high power capacity and large operating bandwidth.

[0015] Furthermore, according to the dispersion characteristics of the pulse compressor, the modulation mode of the input microwave pulse is matched and designed. Specifically, the frequency range with a relatively fast change in group velocity is selected as the working frequency band, and then the width of the input microwave pulse is determined according to the length L of the dispersion structure, so as to construct a non-linear frequency modulation microwave pulse and improve the gain of pulse compression.

[0016] Furthermore, the microwave pulse compressor is prepared with a material of high electrical conductivity, and the structural dimensions and surface roughness of the components are strictly controlled. Ohmic loss and RF breakdown are avoided, so as to ensure the realization of high-efficiency microwave pulse compression.

[0017] (III) Effective benefits

[0018] 1. The high-efficiency microwave pulse compressor of the present invention can effectively improve the peak power of the output microwave pulse, thereby enhancing the performance of the high-power microwave source.

[0019] 2. The microwave pulse compressor of the present invention has the advantages of simple system, compact structure, and large power capacity, providing new technical support for high-repetition-rate arrayed high-power microwave sources. Description of the drawings

[0020] Figure 1 Principle and structural schematic diagram of the high-efficiency microwave pulse compressor of the present invention;

[0021] Figure 2 Dispersion characteristics of the dispersion structure;

[0022] Figure 3 The material of the pulse compressor is selected as pure copper, and the power comparison of the input and output microwave pulses; Detailed implementation manners

[0023] The high-efficiency microwave pulse compressor of the present invention will be described in detail below with reference to the drawings and embodiments.

[0024] First, determine the output microwave frequency range and power level of the pre-stage microwave source, and then design the structural parameters of the high-efficiency microwave pulse compressor according to the technical requirements. The principle and structure of a high-efficiency microwave pulse compressor of the present invention are as Figure 1 shown. The main components include a mode converter, a transition structure, a dispersion structure, a transition structure, a mode converter, and a radiation structure. The above components are used in series in sequence. The mode converter converts the mode of the input microwave pulse into the working mode of the dispersion structure; the transition structure is used to connect the mode converter and the dispersion structure to achieve efficient transmission of the microwave pulse and avoid reflection and generation of non-working modes; the dispersion structure compresses the input frequency-modulated pulse to obtain a compressed microwave pulse with high gain; the subsequent transition structure and mode converter convert the mode of the compressed high-power microwave pulse into the radiated microwave mode again; finally, the radiation structure radiates the high-power microwave pulse to the space target. Among them, the dispersion structure is the core and the key to achieving high-gain and high-efficiency microwave pulse compression.

[0025] Furthermore, according to the output interface and microwave mode of the pre-stage microwave source, a hollow waveguide structure is used to match and design the components of the pulse compressor such as the mode converter, the transition structure, and the dispersion structure. Combining requirements such as microwave mode and antenna gain, a horn feed with a smooth inner wall and variable flare angle is used to design the radiation structure to meet the requirements of high power capacity and large working bandwidth.

[0026] The design of the dispersion structure is introduced in detail. A spiral corrugated waveguide is used, and this structure can be expressed by the following formula:

[0027]

[0028] where, r 0 is the average radius of the spiral corrugated waveguide; r 1 is the corrugation amplitude; m B is the azimuthal wave number; k B = 2π / d is the axial wave number; d is the axial period length.

[0029] In a three-fold spiral corrugated waveguide, that is, m B = ±3, the TE 11 and TE 21 modes are two modes that satisfy the Bragg condition and the azimuthal selection condition, and strong eigen-coupling occurs. The Bragg condition and the azimuthal selection condition are respectively

[0030] k z1 - k z2 = k B (3)

[0031] m 1 - m 2 = m B (4) In the formula: m1 and m 2 are respectively the azimuth numbers of TE 11 and TE 21 ; k z1 and k z2 are respectively the axial wavenumbers of TE 11 and TE 21 .

[0032] Optimize the structural parameters of the helical corrugated waveguide to achieve the best pulse compression effect, and the obtained structural parameters are as follows: r 0 = 45 mm, satisfying within the range of 0.42λ - 0.52λ; r 1 = 3.9 mm, satisfying within the range of 0.34λ - 0.45λ; the axial period d = 86 mm, satisfying within the range of 0.75λ - 0.95λ. λ is the microwave wavelength.

[0033] According to the impedance perturbation and coupling theory of the waveguide, the dispersion characteristics of the dispersion structure in the designed high-efficiency microwave pulse compressor are obtained, as Figure 2 shown. Select 2.8 GHz - 3.17 GHz as the working frequency range, where the group velocity changes rapidly in the frequency band and is far from the cut-off region, which is beneficial to realizing high-gain microwave pulse compression.

[0034] Furthermore, according to the dispersion characteristics of the pulse compressor, match and design the modulation mode of the input microwave pulse. Specifically, select the length L = 6.88 m of the dispersion structure, combine the working frequency band and dispersion characteristics, determine the width of the input microwave pulse to be 316 ns, and then construct a non-linear frequency modulation microwave pulse.

[0035] Furthermore, use pure copper material with high conductivity to prepare the microwave pulse compressor, and strictly control the structural dimensions and surface roughness of the components. Avoid ohmic loss and RF breakdown, so as to ensure the realization of high-efficiency microwave pulse compression.

[0036] The effect of an embodiment of the high-efficiency microwave pulse compressor of the present invention is as Figure 3 shown. Inject a microwave pulse modulation signal with a pulse width of 316 ns into the pulse compressor, and the output microwave pulse width is 5.8 ns, and the power gain is about 44.5 times, that is, 16.5 dB, and the energy transmission efficiency of the entire pulse compressor is 81.7%.

[0037] The beneficial effect brought by the present invention is that the high-efficiency microwave pulse compressor can significantly increase the output microwave pulse power, with the peak power reaching more than 16 dB and the microwave spectrum width reaching more than 10%. Integrating the microwave pulse compressor with a high-power microwave source is expected to improve the overall performance of the high-power microwave system to meet the application requirements in complex electromagnetic environments.

[0038] The above content is a further detailed description of the present invention in combination with specific embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A high-efficiency microwave pulse compressor, characterized in that: It includes a first mode converter, a first transition structure, a dispersion structure, a second transition structure, a second mode converter and a radiation structure, and the above components are used in series; The first mode converter converts the mode of the input microwave pulse into the working mode of the dispersion structure; The first transition structure is used to connect the first mode converter and the dispersion structure; The dispersive structure compresses the input frequency modulated pulse to obtain a high-gain compressed microwave pulse; The second transition structure and the second mode converter convert the compressed high-power microwave pulse mode into a radiated microwave mode again; The radiating structure radiates high-power microwave pulses to space targets; Use hollow waveguide structures to design mode converters, transition structures, dispersion structures, and radiation structures; The dispersion structure adopts a spiral corrugated waveguide. The group velocity of the coupling mode of the spiral corrugated waveguide changes rapidly with the frequency and is far away from the cutoff region. The dispersion structure is expressed by the following formula: Wherein, r0 is the average radius of the spiral corrugated waveguide, and r0 is selected in the range of 0.42λ~0.52λ; r1 is the ripple amplitude, and r1 is selected in the range of 0.34λ~0.45λ; m B is the angular wave number, determined by the angular selection condition; k B =2π / d is the axial wave number, which must satisfy the Bragg condition; d is the axial period length, d satisfies the range of 0.75λ to 0.95λ, and λ is the microwave wavelength.

2. The high-efficiency microwave pulse compressor according to claim 1, characterized in that: The modulation method of the input microwave pulse is designed according to the dispersion characteristics of the pulse compressor, the frequency range with fast group velocity change is selected as the working frequency band, and the width of the input microwave pulse is determined according to the length L of the dispersion structure, thereby constructing a nonlinear frequency modulated microwave pulse and improving the gain of pulse compression.

3. The high-efficiency microwave pulse compressor according to claim 1, characterized in that: 2.8 GHz to 3.17 GHz is selected as the operating frequency range. The group velocity changes rapidly in the frequency band and is far away from the cutoff region, which is conducive to achieving high-gain microwave pulse compression.

4. The high-efficiency microwave pulse compressor according to claim 1, characterized in that: The length of the dispersion structure is selected as L=6.88m, and the width of the input microwave pulse is determined to be 316ns in combination with the working frequency band and dispersion characteristics, thereby constructing a nonlinear frequency modulated microwave pulse.

5. The high-efficiency microwave pulse compressor according to claim 1, characterized in that: A microwave pulse modulation signal with a pulse width of 316ns is injected into the pulse compressor, and the output microwave pulse width is 5.8ns. The power gain is about 44.5 times, i.e. 16.5dB, and the energy transmission efficiency of the entire pulse compressor is 81.7%.

6. The high-efficiency microwave pulse compressor according to claim 1, characterized in that: The high-efficiency microwave pulse compressor increases the output microwave pulse power, the peak power reaches more than 16 dB, and the microwave spectrum width reaches more than 10%.

7. The high-efficiency microwave pulse compressor according to claims 1-6, characterized in that: The radiation structure adopts a variable angle horn feed source with a smooth inner wall.

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