High-resolution imaging method and device based on microwave multiple modes

Abstract

The invention relates to the technical field of target imaging, and provides a high-resolution imaging method and device based on microwave multimodality, and the device comprises a signal source unit, a vortex electromagnetic wave antenna, an echo receiving array, and a control terminal. The signal source unit is used for generating microwave excitation signals and transmitting the microwave excitation signals through the vortex electromagnetic wave transmitting array, and echo signals received by the echo receiving array are processed through the signal processing module of the control terminal; the vortex electromagnetic wave antenna adopts an annular waveguide slot antenna array and comprises an antenna body and a plurality of stacked annular rectangular waveguides arranged in the antenna body, and slots are formed in the walls of the waveguides and used for forming leaky wave radiation to emit vortex electromagnetic waves. Through the arrangement of the annular waveguide slot antenna array, stable emission of multi-modal vortex electromagnetic waves is realized, the target scattering information dimension is enhanced, and the imaging resolution is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field related to target imaging, and in particular to a high-resolution imaging method and device based on microwave multimodality. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] High-resolution target imaging technology has important application value in remote sensing monitoring, battlefield reconnaissance, security inspection, and intelligent manufacturing. In particular, accurate detection and imaging of targets in complex environments are crucial for target recognition and classification. Traditional electromagnetic wave imaging relies on detailed analysis of target reflection signals. However, with the increasing requirements for imaging quality, conventional methods such as linear frequency modulation radar (LFM), synthetic aperture radar (SAR), and inverse synthetic aperture radar (ISAR) face many limitations. Vortex electromagnetic waves are a type of electromagnetic wave with a unique temporal and spatial distribution. Their phase wavefront is vortex-distributed, and the amplitude and phase distribution of the electromagnetic field at different positions in the beam illumination area have spatial differences, providing a physical basis for target detection and resolution. Based on this characteristic, vortex electromagnetic waves can be used to achieve high-resolution imaging of targets.

[0004] Existing microwave imaging technologies primarily include SAR and ISAR. These technologies face the following challenges in practical applications: First, range resolution is limited by signal bandwidth, with a theoretical upper limit of c / 2B (where c is the speed of light and B is the signal bandwidth). Achieving high resolution requires extremely high bandwidth, placing stringent demands on signal generation, modulation, linear calibration, and back-end processing, significantly increasing hardware costs and system complexity. Second, azimuth resolution is limited by antenna aperture size. SAR and ISAR rely on large relative motion angles between the target and the platform to achieve a large synthetic aperture. However, the antenna beam is fixed and has a limited beamwidth, which limits the achievable angular variation and azimuth resolution. Furthermore, SAR / ISAR imaging, based on the principle of coherence, is highly sensitive to environmental coherence and is susceptible to noise and phase perturbations. This results in large grayscale fluctuations between adjacent pixels in the resulting image, reducing image quality and target recognizability. These issues are particularly pronounced in applications such as imaging complex scenes and non-cooperative targets. Summary of the Invention

[0005] In order to solve the above problems, the present invention proposes a high-resolution imaging method and device based on microwave multimodality. Without the need for phased array control, a ring-shaped waveguide slot antenna array is set up to achieve stable emission of multimodal vortex electromagnetic waves, enhance the target scattering information dimension, and significantly improve imaging resolution.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] One or more embodiments provide a high-resolution imaging device based on microwave multimodality, including a signal source unit, a vortex electromagnetic wave antenna, an echo receiving array, and a control terminal; the signal source unit is used to generate a microwave excitation signal, which is transmitted through the vortex electromagnetic wave transmitting array, and the echo signal received by the echo receiving array is processed by a signal processing module of the control terminal;

[0008] The vortex electromagnetic wave antenna adopts an annular waveguide slot antenna array, which includes an antenna body, multiple stacked annular rectangular waveguides arranged in the antenna body, and slots arranged on the waveguide wall to form leakage waves to radiate vortex electromagnetic waves.

[0009] One or more embodiments provide an imaging method based on the above-mentioned microwave multi-modal high-resolution imaging device, comprising the following steps:

[0010] Control the microwave switch to switch different modes of vortex electromagnetic waves and transmit the vortex electromagnetic waves to the target to be detected in sequence;

[0011] The scattered echo signals of each mode are acquired through the echo receiving array, and the multi-modal response signals are obtained by combining the response characteristics of the target to different modes.

[0012] The multimodal response signal is processed using information decoupling and super-resolution reconstruction algorithms to extract the target's spatial position information and scattering characteristics information to obtain imaging results. Compared with the existing technology, the present invention has the following beneficial effects:

[0013] The present invention adopts a ring-shaped waveguide slot antenna array as the emission structure of vortex electromagnetic waves, and realizes multi-modal electromagnetic excitation without introducing a complex phased array system, which significantly simplifies the structural design and control complexity of the antenna system. The antenna array evenly arranges slot units on the wall of the ring waveguide, so that the microwave signal leaks uniformly along the ring path and radiates into space, naturally forming a vortex electromagnetic wave with a spiral phase front. Compared with traditional plane waves, vortex electromagnetic waves have rich spatial phase information and orbital angular momentum characteristics, which can stimulate more complex scattering responses of the target, so that the received echo signal is greatly improved in both dimension and information volume. By fusing multiple modal echoes for reconstruction, the ability to restore the details of the target imaging is greatly enhanced, the imaging resolution of the system is significantly improved, and the resolution bottleneck problem of traditional microwave imaging, which is limited by the signal bandwidth and target geometric characteristics, is solved, providing an effective solution for high-precision detection in complex scenes.

[0014] The advantages of the present invention and its additional aspects will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their description are used to explain the present invention but do not constitute a limitation of the present invention.

[0016] Figure 1 1 is a schematic structural diagram of a high-resolution imaging device based on microwave multimodality according to embodiment 1 of the present invention;

[0017] FIG2( a ) is a schematic structural diagram of a ring-shaped waveguide slot antenna array according to Example 1 of the present invention;

[0018] FIG2( b ) is a schematic diagram of the first viewing angle of the annular rectangular waveguide according to embodiment 1 of the present invention.

[0019] FIG2( c ) is a schematic top view of the annular rectangular waveguide according to Example 1 of the present invention;

[0020] FIG2( d ) is a schematic side view of the structure of the annular rectangular waveguide according to Example 1 of the present invention;

[0021] Figure 3 Schematic diagram of three different modes of transverse vortex electromagnetic modes generated by the annular waveguide slot antenna array of Example 1 of the present invention;

[0022] Figure 4 1 is a wavefront amplitude distribution diagram of different modes of vortex electromagnetic waves in Example 1 of the present invention;

[0023] Figure 5 1 is a wavefront phase distribution diagram of different modes of vortex electromagnetic waves in Example 1 of the present invention;

[0024] Figure 6 is the original distribution diagram of the simulation experiment of Example 1 of the present invention;

[0025] Figure 7 1 is an imaging result diagram of a simulation experiment using a high-resolution imaging device based on microwave multi-mode in Example 1 of the present invention; DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0028] It should be noted that the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof. It should be noted that, in the absence of conflict, the various embodiments of the present invention and the features in the embodiments can be combined with each other. The embodiments will be described in detail below with reference to the accompanying drawings.

[0029] Example 1

[0030] In the technical solutions disclosed in one or more embodiments, Figures 1 to 7 As shown, the high-resolution imaging device based on microwave multimodality includes: a signal source unit, a vortex electromagnetic wave antenna, an echo receiving array, and a control terminal; the signal source unit is used to generate a microwave excitation signal and transmit it through the vortex electromagnetic wave transmitting array, and the echo signal received by the echo receiving array is processed by the signal processing module of the control terminal;

[0031] The vortex electromagnetic wave antenna adopts an annular waveguide slot antenna array, which includes an antenna body, multiple stacked annular rectangular waveguides arranged in the antenna body, and slots arranged on the waveguide wall to form leakage waves to radiate vortex electromagnetic waves.

[0032] In this embodiment, a ring antenna array is used based on a ring-shaped rectangular waveguide, and a number of slot units are arranged on the waveguide wall to realize leakage wave radiation under the action of the excitation signal. Through the structural design and arrangement control of the slot array, the device can form vortex electromagnetic waves without the need for complex phased array control. The generated vortex electromagnetic waves have a spiral phase front characteristic, that is, their phase shows a rotational change in space, so that the electromagnetic waves carry orbital angular momentum. These vortex electromagnetic waves with specific modes are used as imaging excitation waves and irradiated to the target to be measured. Under the action of this type of electromagnetic wave, the target surface will induce an electromagnetic response different from the traditional plane wave, thereby generating a feature-rich scattered echo. After the echo signal is received by the echo receiving array, it is transmitted to the signal processing module in the control terminal, which processes the received echo and finally obtains the target imaging result.

[0033] This embodiment uses a ring-shaped waveguide slot antenna array as the emission structure of the vortex electromagnetic wave, and realizes multi-modal electromagnetic excitation without introducing a complex phased array system, which significantly simplifies the structural design and control complexity of the antenna system. The antenna array evenly arranges slot units on the wall of the ring waveguide, so that the microwave signal leaks uniformly along the ring path and radiates into space, naturally forming a vortex electromagnetic wave with a spiral phase front. Compared with traditional plane waves, vortex electromagnetic waves have rich spatial phase information and orbital angular momentum characteristics, which can stimulate more complex scattering responses of the target, so that the received echo signal is greatly improved in both dimension and information volume. By fusing multiple modal echoes for reconstruction, the ability to restore the details of the target imaging is greatly enhanced, the imaging resolution of the system is significantly improved, and the resolution bottleneck problem of traditional microwave imaging, which is limited by the signal bandwidth and target geometric characteristics, is solved, providing an effective solution for high-precision detection in complex scenes.

[0034] In some embodiments, the structure of a ring-shaped waveguide slot antenna array is shown in Figure 2(a). The inner wall of the antenna body is a reflective wall with a predetermined curvature. Ring-shaped rectangular waveguides with different wavelength modes are stacked sequentially within the antenna body. Slots are provided on the outer walls of the rectangular waveguides to create leakage spaces. As shown in Figure 2(a), three stacked rectangular waveguides are used as an example, with rectangular waveguides configured for a double wavelength mode, a triple wavelength mode, and a quadruple wavelength mode, respectively.

[0035] Furthermore, to ensure that the radiation directions of different modes are consistent, the waveguide is a rectangular structure with a wide side and a short side. A method of slits on the short side of the waveguide can be used, with slits extending outward from the waveguide wall along the short side of the waveguide. Specifically, as shown in Figure 2(b), a portion of a rectangular waveguide is cut out, and the cut end face is rectangular, with the horizontal direction being the long side of the waveguide and the vertical direction (the z direction of the coordinate system in the figure) being the short side of the rectangular waveguide. Slits are set on the outer short side of the rectangular waveguide, allowing electromagnetic waves to be emitted outward from the center of the waveguide ring. As shown in Figure 2(a), the electromagnetic wave emitted outward through the set slit is the outgoing wave, which is reflected by the reflective wall to form an emitted wave with the same direction.

[0036] In a ring-shaped waveguide structure, the beam radiated through the slits on the waveguide wall exhibits different angles in space. This means that the vortex modes have different angles (i.e., the angles at which the beam spreads in space). Consequently, the radiation directions of different modes vary. To ensure that the main radiation directions of all modes are consistent, this solution uses slits on the short sides of the waveguide. This has the following effects:

[0037] Changing the directivity of leaky waves: Slits on the short sides make the radiation direction closer to the radial direction (perpendicular to the annular path), facilitating the unification of the radiation direction;

[0038] Enhanced modal consistency: Align the main lobes of different modes in a general direction to avoid information aliasing caused by inconsistent scattering directions. The main lobe is the area of radiation within an antenna or radiation beam with the highest energy and most concentrated direction, also known as the main beam or main radiation direction.

[0039] Because different modes of vortex waves have different beam angles (for example, modes l = 1, 2, and 3 have different beam angles), if they are radiated directly, these modes will propagate at different angles in space, resulting in inconsistent receiving point positions on the imaging plane, affecting image reconstruction.

[0040] Furthermore, the wall surface of the reflecting wall is set to a U-shaped structure, which extends outward from the bottom to the top of the U-shaped structure wall in accordance with the set curvature to form an arc-shaped reflecting surface, thereby reflecting electromagnetic waves of different modes to the same direction, thereby realizing the emission of vortex waves of different modes, as shown in Figure 2(a).

[0041] Specifically, in this embodiment, an arc-shaped metal reflective wall is provided in the radiation direction of each slot, which may be in the shape of a horn, to reflect the waves leaking from the slot into a beam in a fixed direction;

[0042] The device of this embodiment needs to jointly image the echo information of multiple modes. If the radiation direction of each mode is different, the echo signal coverage area will not overlap, and the information cannot be effectively fused; the imaging surface is difficult to reconstruct, which affects the resolution improvement. Setting a curved reflective surface can improve the imaging resolution.

[0043] In some embodiments, the structure of the ring-shaped rectangular waveguide is as follows Figure 2(b) to Figure 2(d) As shown, the entire waveguide is annular, the hollow space between the annular outer walls forms the transmission space for the signal inside the waveguide, and the cross-section of the annular outer walls is rectangular.

[0044] Furthermore, a controllable microwave switch array is provided on the coupling path between the signal source unit and the vortex electromagnetic wave transmitting array, and each microwave switch is connected to the annular rectangular waveguide of the annular waveguide slot antenna array through a millimeter wave frequency multiplier;

[0045] Optionally, the microwave switch uses a controllable switch, which may be a PIN diode, a MEMS switch, or a voltage-controlled capacitor, to control the effective propagation path length of the electromagnetic wave in the ring waveguide;

[0046] like Figure 3 As shown in the figure, traveling waves can be generated in the annular rectangular waveguide cavity, and by adjusting the electrical length of the electromagnetic wave in the waveguide through the on and off of the microwave switch, traveling wave modes of different wavelengths can be generated. Figure 3 The three vortex electromagnetic modes a, b, and c in the figure are three transverse vortex electromagnetic modes with different modes generated by leakage waves from the annular waveguide gap.

[0047] Furthermore, by adjusting the radius of the set annular rectangular waveguide, the phase difference generated by the transmission of the electromagnetic wave in the waveguide and the topological charge number of the radiated vortex electromagnetic wave are adjusted; as shown in Figure 2(a), taking three stacked rectangular waveguides as an example, rectangular waveguides with double wavelength mode, triple wavelength mode and quadruple wavelength mode are set respectively.

[0048] Phase difference refers to the phase difference between two points of the radiating slot in the waveguide; the phase difference determines the synthetic shape of the radiation wave from each slot in space, such as plane wave, spiral wave, etc.

[0049] Topological charge is an important parameter of vortex electromagnetic waves, indicating the number of cycles of phase change within a complete cycle.

[0050] The propagation path length between any two points in the rectangular slot depends on the arc length s of the waveguide ring, that is:

[0051] s=R×Δφ;

[0052] Where R is the waveguide radius and Δφ is the spacing angle between the two slots.

[0053] Electromagnetic propagation in a waveguide experiences phase accumulation. The larger the radius, the longer the propagation path at the same angular interval, and the greater the phase difference. The phase difference is calculated as follows:

[0054] Δθ=β×s=β×R×Δφ;

[0055] Here, β = 2π / λ is the phase constant in the waveguide, and λ is the waveguide wavelength.

[0056] Therefore, by setting up multiple ring waveguides with different radii, each waveguide radiates a different mode, the topological charge number can be adjusted.

[0057] For example, if 8 points are selected in the slot, if the phase difference between adjacent points is 2π / 8=45°, then the phase rotates one circle (360°) and the topological charge number l=1; if the phase difference between the slots is 90°, then the phase rotates one circle (360°) and the topological charge number l=2; higher topological charge requires a larger phase difference, which can be achieved by increasing the waveguide radius.

[0058] In some embodiments, the signal source unit includes a fast frequency modulation transceiver module, a microwave frequency multiplier, a microwave switch array, and a microwave power splitter;

[0059] The fast frequency modulation transceiver module specifically uses a digital signal synthesizer (DDS) (RF / LO) to generate radio frequency (RF) and local oscillator (LO) signals. After the radio frequency (RF) signal is amplified by the microwave frequency multiplier, it generates a microwave excitation signal to drive the transmitting antenna. The echo signal is down-converted at the receiving end to generate an intermediate frequency (IF) signal.

[0060] A microwave frequency multiplier is used to amplify the power of the signal output by the fast frequency modulation transceiver module;

[0061] The radio frequency signal output by the fast frequency modulation transceiver module is distributed as needed to multiple antenna channels of the vortex electromagnetic wave antenna through the microwave switch array. The different modes of vortex wave transmission channels are controlled by electronic switches. Each channel has an adjustable switching path for switching the vortex mode (topological charge number).

[0062] The microwave power splitter distributes the local oscillator (LO) signal output by the fast frequency modulation transceiver module to each down-conversion receiving channel. It ensures the synchronization of the mixer's local oscillator port, which is conducive to phase-coherent sampling of multi-channel echoes.

[0063] In some embodiments, the echo receiving array transmits the received echo signal to the control terminal through the multi-channel mixing module and the multi-channel ADC module;

[0064] The echo receiving array uses a millimeter wave horn antenna;

[0065] The multi-channel mixing module sets a mixer for each millimeter-wave horn antenna, uses the power-divided local oscillator signal output by the microwave power divider as a mixing reference, and converts the echo signal received by the millimeter-wave horn antenna into an intermediate frequency (IF) signal through mixing processing;

[0066] The multi-channel ADC module sets a sampling channel for each mixer and samples the intermediate frequency signal output by the mixer; the channels are sampled synchronously to maintain time consistency between modes.

[0067] Furthermore, a multi-channel spread spectrum processing module is also provided at the output end of the multi-channel ADC module, which is used to perform spread spectrum coding processing on the sampled multi-channel data, improve the system's anti-interference ability, and retain the characteristic differences between modes for subsequent inversion and reconstruction.

[0068] In some embodiments, the control terminal is provided with a main control all-in-one machine (PC+GPU) and FPGA, which is used to control the switch switching logic and implement the modal scheduling strategy of the electromagnetic wave; and is used to perform synchronous management and demodulation processing of the sampled data;

[0069] The main control unit is equipped with a signal processing unit for performing modal separation, feature decoupling, reconstruction and super-resolution processing on the received wave signals to obtain a high-resolution image of the target.

[0070] In an optional embodiment, a mechanical scanning device is further provided to adjust the direction of the echo receiving array, thereby enabling multi-directional automatic target detection and imaging.

[0071] The traditional microwave imaging method uses a single plane wave incident with a single scattering characteristic, and the inferred detection target is only inferred by the response of a single incident wave. This embodiment converts the plane electromagnetic wave used for detection into a vortex electromagnetic wave through a ring waveguide slot antenna array, which has a vortex-shaped phase distribution, and different modal vortex electromagnetic waves are orthogonal to each other. The phase wavefront distribution of different modal vortex electromagnetic waves makes the induced electromagnetic current generated on the surface of the target to be measured different from that in the case of a single plane incident wave, and the scattered echo will contain richer target information. When different modal vortex electromagnetic waves are used for target detection, the target to be measured is excited by different modal electromagnetic waves, and its scattering information and key response characteristics provide a new dimension for target imaging. Switching different modes and combining scattering characteristics can effectively improve imaging resolution.

[0072] Example 2

[0073] Based on Example 1, this embodiment provides an imaging method based on the microwave multi-modal high-resolution imaging device described in Example 1, which can be implemented in a control device, including the following steps:

[0074] Step 1: Control the microwave switch to switch between different modes of vortex electromagnetic waves, and sequentially transmit the vortex electromagnetic waves to the target to be detected;

[0075] Step 2: Acquire scattered echo signals of each mode through the echo receiving array, combine them according to the target's response characteristics to different modes, and obtain a multi-modal response signal;

[0076] Step 3: Use information decoupling and super-resolution reconstruction algorithms to process the multimodal response signals, extract the spatial position information and scattering characteristic information of the target, and obtain the imaging results.

[0077] In step 1, when the microwave switch is set to conduct a certain path, a certain modal vortex wave is incident. The incident wave irradiates the target to be detected and generates a scattering field. The probe of the echo receiving array performs a planar scan on the target to be detected, and collects the response information of this modal vortex wave incident condition, that is, the scattered echo signal; by switching different channels, different modal vortex waves are incident, thereby obtaining different modal response characteristics.

[0078] The combination of the signals in step 2 is to superimpose the signals according to their time axis;

[0079] Step 3: Use information decoupling and super-resolution reconstruction algorithms to process multimodal response signals. By sampling the scattering fields under different modal incident waves, that is, the response characteristics of different modes, the images of the different modal scattering fields are calculated using a full-wave quantitative algorithm, and the calculated images are spliced according to the characteristic information to obtain high-resolution imaging results.

[0080] Furthermore, in step 2, the probe of the echo receiving array is driven by a mechanical scanning device to perform a two-dimensional plane scanning motion, and the probe of the echo receiving array receives vortex wave scattering information of different modes by moving;

[0081] Furthermore, when the obtained imaging result cannot show the complete object, it is determined to be a large-size target; the target area is divided into multiple grid areas, and steps 1 to 3 are executed one by one for each target area to complete detection and imaging, and a three-dimensional high-resolution image of the complete target is reconstructed through image stitching and fusion.

[0082] The mechanical scanning device can rotate or move, driving the echo receiving array to perform two-dimensional plane scanning movement. After the data of each sampling point is collected, three-dimensional high-resolution imaging of the measured target can be achieved through error calibration. For large-scale targets, the target needs to be divided into grids. After completing the collection and imaging processing of each grid area in turn, three-dimensional high-resolution imaging of the large-scale target can be achieved through image stitching and fusion.

[0083] In order to illustrate the effect of the method of this embodiment, a simulation experiment was carried out. The multi-mode vortex electromagnetic wave used is as follows Figure 4 and Figure 5 As shown, Figure 4 is the 5 modal amplitude distribution, Figure 5 is the corresponding phase distribution.

[0084] Two uniform square cylinders with a side length of λ / 2 are placed in the center of the target area. The distance between the edges of the square cylinders is λ / 4. The dielectric constant of the two square cylinders is 3, as shown in the following example: Figure 6 The operating frequency is set to 110 GHz and the regularization parameter is 0.01. Figure 4 The five modes of vortex electromagnetic waves are used to image the two targets, and the following results are obtained: Figure 7 The imaging structure shown in the figure can clearly distinguish two targets with a distance of λ / 4, achieving a high resolution better than λ / 2. Figure 6 and Figure 7 The figure is divided into two parts, the left figure is the real part of the complex dielectric constant, and the right figure is the imaginary part of the complex dielectric constant.

[0085] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

[0086] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A high-resolution imaging device based on microwave multimodality, characterized by: It includes a signal source unit, a vortex electromagnetic wave antenna, an echo receiving array and a control terminal; the signal source unit is used to generate a microwave excitation signal which is transmitted through the vortex electromagnetic wave transmitting array, and the echo signal received by the echo receiving array is processed by the signal processing module of the control terminal; The vortex electromagnetic wave antenna adopts an annular waveguide slot antenna array, which includes an antenna body, multiple stacked annular rectangular waveguides arranged in the antenna body, and slots arranged on the waveguide wall to form leakage waves to radiate vortex electromagnetic waves.

2. The high-resolution imaging device based on microwave multimodality according to claim 1, characterized in that: The inner wall of the antenna body is a reflective wall with a set curvature. Annular rectangular waveguides with different wavelength modes are stacked in sequence inside the antenna body. Gaps are set on the outer walls of the rectangular waveguides to form leakage spaces.

3. The high-resolution imaging device based on microwave multimodality according to claim 1, characterized in that: The annular rectangular waveguide is a rectangular structure including a wide side and a short side, and a gap is provided on the waveguide wall of the short side of the waveguide extending outward.

4. The high-resolution imaging device based on microwave multimodality according to claim 1, characterized in that: The inner wall of the antenna body is a reflective wall with a set curvature. Annular rectangular waveguides with different wavelength modes are stacked in sequence inside the antenna body. Gaps are set on the outer walls of the rectangular waveguides to form leakage spaces.

5. The high-resolution imaging device based on microwave multimodality according to claim 1, characterized in that: A controllable microwave switch array is set on the coupling path between the signal source unit and the vortex electromagnetic wave transmitting array. Each microwave switch is connected to the annular rectangular waveguide of the annular waveguide slot antenna array through a millimeter wave frequency multiplier.

6. The high-resolution imaging device based on microwave multimodality according to claim 5, characterized in that: Microwave switches use PIN diodes, MEMS switches, or voltage-controlled capacitors.

7. The high-resolution imaging device based on microwave multimodality according to claim 1, characterized in that: By adjusting the radius of the set annular rectangular waveguide, the phase difference generated by the transmission of the electromagnetic wave in the waveguide and the topological charge number of the radiated vortex electromagnetic wave are adjusted.

8. The high-resolution imaging device based on microwave multimodality according to claim 1, characterized in that: The signal source unit includes a fast frequency modulation transceiver module, a microwave frequency multiplier, a microwave switch array, and a microwave power divider; Fast FM transceiver module, specifically using a digital signal synthesizer DDS to generate RF and local oscillator signals; A microwave frequency multiplier is used to amplify the power of the signal output by the fast frequency modulation transceiver module; Microwave power splitter, used to distribute the local oscillator signal output by the fast frequency modulation transceiver module; The echo receiving array transmits the received echo signal to the control terminal through the multi-channel mixing module and the multi-channel ADC module; A mechanical scanning device is also provided for adjusting the direction of the echo receiving array.

9. The imaging method according to any one of claims 1 to 8, wherein: The steps include: Control the microwave switch to switch different modes of vortex electromagnetic waves and transmit the vortex electromagnetic waves to the target to be detected in sequence; The scattered echo signals of each mode are acquired through the echo receiving array, and the multi-modal response signals are obtained by combining the response characteristics of the target to different modes. The multimodal response signals are processed using information decoupling and super-resolution reconstruction algorithms to extract the target's spatial position information and scattering characteristic information to obtain imaging results.

10. The imaging method according to claim 9, wherein The steps include: The mechanical scanning device drives the echo receiving array probe to perform two-dimensional plane scanning motion, and the echo receiving array probe receives vortex wave scattering information of different modes by moving; Alternatively, when the target is large, the target area is divided into multiple grid areas, each target area is detected and imaged, and the imaging results of each grid are stitched and fused to reconstruct the image of the target.

Images