A high-efficiency microwave pulse compressor

Abstract

This invention discloses a high-efficiency microwave pulse compressor, belonging to the field of high-power microwave technology. 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. These components are connected in series. The first mode converter converts the mode of the input microwave pulse into the operating mode of the dispersion structure. The mode-converted microwave pulse is efficiently transmitted to the dispersion structure via the transition structure. The dispersion structure compresses the input frequency-modulated pulse. The second transition structure and the second mode converter convert the compressed high-power short pulse into the microwave mode required for radiation. The radiation structure directionally radiates the high-power short microwave pulse to a space target. This high-efficiency microwave pulse compressor features a simple system, compact structure, and large power capacity. It has good application prospects in microwave source arraying and modularization, and is expected to improve the performance of high-power microwave systems.

Description

Technical Field

[0001] This invention belongs to the field of high-power microwave technology and relates to a high-efficiency microwave pulse compressor. Background Technology

[0002] Today, countries worldwide are accelerating the development of equipment systems towards unmanned and intelligent operation. Electronic information equipment, systems, and networks are becoming increasingly abundant, and the electromagnetic environment is becoming increasingly complex. In the face of the struggle for electromagnetic dominance in this complex electromagnetic environment, high-power microwave sources with wide-spectrum characteristics are one of the key means to achieve strategic initiative. Wide-spectrum high-power microwave generation technologies mainly include frequency tuning, superradiation, and pulse compression. Among these, pulse compression compresses low-power long microwave pulses into high-power short microwave pulses, achieving power gains of several to tens of times. Due to its modularity and array-like advantages, microwave pulse compression has become a promising high-power microwave generation technology.

[0003] Pulse compression technology has been widely used in the field of accelerators to accelerate charged particles. With the development of technology, its application in the field of high-power microwaves is increasing. Several typical pulse compression techniques are introduced below. In 2015, researchers proposed a five-fold helical corrugated waveguide and applied it to passive pulse compression research. In the experiment, the microwave pulse width of 80ns was compressed to 1.6ns, with a corresponding energy efficiency of 66.3%, and the X-band microwave pulse compression gain was about 14dB (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 cavities, a compact two-stage pulse compressor was designed on a dual-speed tube high-power platform. This pulse compressor achieved a power gain of up to 13 dB, breaking the gain limit of 9 dB for passive pulse compressors (Wang Ping. Research on Novel High-Power Microwave Pulse Compressors [D]. Beijing: Tsinghua University, 2018). In 2023, researchers, based on microwave chaotic cavities and a time-reversal model, theoretically increased the compression gain by 6 dB to 12 dB, with experimental results ranging from 5 dB to 8.5 dB (Lu Xicheng. Research on Microwave Chaotic Cavity Time-Reversal Pulse Compression Technology and Its Application [D]. Xi'an: Xi'an University of Electronic Science and Technology, 2023).

[0004] Currently, various pulse compression methods have received considerable attention and research. Methods such as energy storage resonant cavities and energy multipliers offer high power gains, but suffer from relatively complex systems and limited power capacity. Pulse compression methods based on microwave chaotic cavities offer high gain and simple structure, but face challenges such as large size and low energy transfer efficiency. Research results indicate that due to energy losses in pulse compression systems, the efficiency of pulse compressors is typically below 60%. Therefore, it is necessary to explore higher-efficiency microwave pulse compressors to meet the application requirements of high-power microwave applications. Summary of the Invention (I) Summary of the Invention

[0006] The purpose of this 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] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0009] A high-efficiency microwave pulse compressor was designed, comprising a first mode converter, a first transition structure, a dispersion structure, a second transition structure, a second mode converter, and a radiation structure, all connected in series. The first mode converter transforms the input microwave pulse mode into the operating mode of the dispersion structure. The first transition structure connects the mode converter and the dispersion structure, enabling efficient microwave pulse transmission and avoiding reflections and non-operating modes. The dispersion structure compresses the input frequency-modulated pulse to obtain a high-gain compressed microwave pulse. The subsequent second transition structure and second mode converter convert the compressed high-power microwave pulse mode back into a radiated microwave mode. Finally, the radiation structure radiates the high-power microwave pulse to a space target. The dispersion structure is the core component and is crucial for achieving high-gain and high-efficiency microwave pulse compression.

[0010] Furthermore, the system's power capacity is improved by employing hollow waveguide structures to design pulse compressor components such as mode converters, transition structures, dispersive structures, and radiating structures.

[0011] The dispersive structure can employ a helical corrugated waveguide, whose group velocity of the coupling modes changes rapidly with frequency and is far from the cutoff region, which is beneficial for achieving high-gain microwave pulse compression. This structure can be expressed by the following equation:

[0012]

[0013] Where r0 is the average radius of the helical corrugated waveguide, and r0 is selected in the range of 0.42λ to 0.52λ; r1 is the ripple amplitude, and r1 is selected in the range of 0.34λ to 0.45λ; m B The angular wavenumber is determined by the angular selection criteria; k B =2π / d is the axial wavenumber, which must satisfy the Bragg condition; d is the axial period length, which must be within the range of 0.75λ to 0.95λ. λ is the microwave wavelength.

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

[0015] Furthermore, the modulation scheme of the input microwave pulse is designed based on the dispersion characteristics of the pulse compressor. Specifically, a frequency range with rapid group velocity changes is selected as the operating 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.

[0016] Furthermore, the microwave pulse compressor is fabricated using materials with high electrical conductivity, and the structural dimensions and surface roughness of its components are strictly controlled. This avoids ohmic losses and radio frequency breakdown, thereby ensuring high-efficiency microwave pulse compression.

[0017] (III) Effective Returns

[0018] 1. The high-efficiency microwave pulse compressor of the present invention can effectively improve the peak power of the output microwave pulse, thereby improving the efficiency 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. Attached Figure Description

[0020] Figure 1 A schematic diagram illustrating the principle and structure of the high-efficiency microwave pulse compressor of this invention;

[0021] Figure 2 Dispersive properties of dispersive structures;

[0022] Figure 3 The pulse compressor is made of pure copper, and the power of the input and output microwave pulses is compared. Detailed Implementation

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

[0024] First, the output microwave frequency range and power level of the pre-stage microwave source are determined. Then, based on technical requirements, the structural parameters of the high-efficiency microwave pulse compressor are designed. The principle and structure of a high-efficiency microwave pulse compressor of this invention are as follows: Figure 1 As shown, the main components include a mode converter, a transition structure, a dispersion structure, a mode converter again, and a radiation structure, all connected in series. The mode converter transforms the mode of the input microwave pulse into the operating mode of the dispersion structure; the transition structure connects the mode converter and the dispersion structure, enabling efficient microwave pulse transmission and avoiding reflections and non-operating modes; the dispersion structure compresses the input frequency-modulated pulse to obtain a high-gain compressed microwave pulse; the subsequent transition structure and mode converter transform the compressed high-power microwave pulse mode back into a radiated microwave mode; finally, the radiation structure radiates the high-power microwave pulse to the space target. Among these components, the dispersion structure is the core and crucial for achieving high-gain and high-efficiency microwave pulse compression.

[0025] Furthermore, based on the output interface and microwave mode of the preceding microwave source, a hollow waveguide structure is used to match the design of pulse compressor components such as the mode converter, transition structure, and dispersion structure. Considering the requirements of the microwave mode and antenna gain, a variable-angle horn feed design with a smooth inner wall is adopted to meet the needs of high power capacity and large operating bandwidth.

[0026] The focus is on the design of the dispersive structure, which employs a helical corrugated waveguide. This structure can be represented by the following equation:

[0027]

[0028] Where r0 is the average radius of the helical corrugated waveguide; r1 is the ripple amplitude; m B Angular wave number; k B =2π / d is the axial wave number; d is the axial period length.

[0029] In a triple-fold helical waveguide, i.e. m B =±3,TE 11 and TE 21 The two modes satisfying the Bragg condition and the angular selection condition exhibit strong intrinsic coupling. The Bragg condition and the angular selection condition are respectively...

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

[0031] m1-m2=m B (4) Where m1 and m2 are respectively TE 11 and TE 21 The azimuth angle; k z1and k z2 TE 11 With TE 21 axial wave number.

[0032] To achieve optimal pulse compression, the structural parameters of the helical corrugated waveguide were optimized, resulting in the following parameters: r0 = 45 mm, within the range of 0.42λ to 0.52λ; r1 = 3.9 mm, within the range of 0.34λ to 0.45λ; and axial period d = 86 mm, within the range of 0.75λ to 0.95λ. λ represents the microwave wavelength.

[0033] Based on waveguide impedance perturbation and coupling theory, the dispersive characteristics of the dispersive structure in the designed high-efficiency microwave pulse compressor are obtained, such as... Figure 2 As shown. The operating frequency range of 2.8 GHz to 3.17 GHz was selected. This range has a relatively fast group velocity change and is far from the cutoff region, which is beneficial for achieving high-gain microwave pulse compression.

[0034] Furthermore, the modulation scheme of the input microwave pulse is designed based on the dispersion characteristics of the pulse compressor. Specifically, 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 based on the operating frequency band and dispersion characteristics, thereby constructing a nonlinear frequency modulated microwave pulse.

[0035] Furthermore, a microwave pulse compressor is fabricated using pure copper material with high electrical conductivity, and the structural dimensions and surface roughness of the components are strictly controlled. This avoids ohmic losses and radio frequency breakdown, thereby ensuring high-efficiency microwave pulse compression.

[0036] An embodiment of the high-efficiency microwave pulse compressor of the present invention has the following effects: Figure 3 As shown, when a microwave pulse modulation signal with a pulse width of 316ns is injected into the pulse compressor, the output microwave pulse width is 5.8ns, the power gain is approximately 44.5 times, or 16.5dB, and the energy transfer efficiency of the entire pulse compressor is 81.7%.

[0037] The beneficial effects of this invention are that the high-efficiency microwave pulse compressor can significantly improve the output microwave pulse power, with a peak power exceeding 16 dB and a microwave spectrum width exceeding 10%. Integrating the microwave pulse compressor with a high-power microwave source is expected to improve the overall performance of high-power microwave systems to meet the application requirements of complex electromagnetic environments.

[0038] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection 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, with the above components connected in series; The first mode converter converts the mode of the input microwave pulse into the operating mode of the dispersive 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 back into the radiated microwave mode. The radiating structure radiates high-power microwave pulses toward space targets; The mode converter, transition structure, dispersion structure and radiation structure are designed using a hollow waveguide structure; The dispersive structure employs a helical corrugated waveguide. The group velocity of the coupled modes in the helical corrugated waveguide changes rapidly with frequency and is far from the cutoff region. The dispersive structure is expressed by the following equation: Where r0 is the average radius of the helical corrugated waveguide, and r0 is selected in the range of 0.42λ to 0.52λ; r1 is the ripple amplitude, and r1 is selected in the range of 0.34λ to 0.45λ; m B The angular wavenumber is determined by the angular selection criteria. k B =2π / d is the axial wave number, which must satisfy the Bragg condition; d is the periodic length along the axis, and d is within the range of 0.75λ to 0.95λ, where λ is the microwave wavelength; The modulation scheme of the input microwave pulse is designed based on the dispersion characteristics of the pulse compressor. The frequency range with rapid group velocity change is selected as the working frequency band. 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.

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

3. The high-efficiency microwave pulse compressor according to claim 1, characterized in that: The length of the dispersive structure was selected as L = 6.88m. Based on the operating frequency band and dispersive characteristics, the width of the input microwave pulse was determined to be 316ns, and then a nonlinear frequency modulated microwave pulse was constructed.

4. 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, with a power gain of approximately 44.5 times, or 16.5dB. The energy transfer efficiency of the entire pulse compressor is 81.7%.

5. 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, with a peak power of over 16dB and a microwave spectrum width of over 10%.

6. The high-efficiency microwave pulse compressor according to any one of claims 1-5, characterized in that: The radiation structure employs a variable-angle horn feed with a smooth inner wall.

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