A waveguide slot antenna, antenna array, detection device and information system

Abstract

The specification provides a waveguide slot antenna, an antenna array, a detection device and an information system. The antenna comprises a slow wave structure and a radiation unit. The slow wave structure comprises a plurality of straight waveguide cavities and connecting waveguide cavities. Two adjacent straight waveguide cavities are connected by the connecting waveguide cavities. The straight waveguide cavities define a waveguide narrow side in a cross section. The radiation unit is arranged on a radiation surface opposite to a layout surface of the waveguide narrow side. The radiation unit comprises an array of inclined slots. The inclined slots have an inclination angle relative to a center line of the waveguide narrow side. Each straight waveguide cavity is spaced apart from a plurality of inclined slots along a longitudinal direction on the radiation surface. The waveguide slot antenna, the antenna array, the detection device and the information system provided by the application can obtain a larger frequency scanning angle while reducing side lobes.

Description

Technical Field

[0001] This application relates to the field of antenna technology, specifically to a waveguide slot antenna, antenna array, detection device, and information system. Background Technology

[0002] Slow-wavelength line structures, with their unique transmission characteristics, exhibit significant advantages in the field of angular scanning. They not only greatly expand the angular scanning range but also achieve omnidirectional scanning modes with positive and negative symmetry, effectively eliminating detection blind spots. For example... Figure 1 As shown, in a waveguide slot antenna with a slow-wave line and a wide-side vertical slot, at high frequencies, the side length 'a' of the wide side of the slow-wave line must be greater than λ / 2. However, the spacing 'g' between adjacent waveguide elements is generally greater than 0.5 mm due to manufacturing limitations. This limitation results in a large distance between the radiating slots on two adjacent waveguide elements on the slow-wave line. Consequently, during large-angle scanning, the large-angle beam generated by the radiating slots radiating electromagnetic signals outward will produce sidelobes, making beam narrowing impossible. Utility Model Content

[0003] In order to solve at least one technical problem existing in the prior art, one object of this application is to provide a waveguide slot antenna, antenna array, detection device and information system that can reduce sidelobes while obtaining a large frequency sweep angle.

[0004] To achieve at least one of the above objectives, this application adopts the following technical solution: A waveguide slot antenna includes a slow-wave structure and a radiating element. The slow-wave structure includes a plurality of straight waveguide cavities and a connecting waveguide cavity. The plurality of straight waveguide cavities are arranged at intervals along an extension direction, and adjacent two straight waveguide cavities are connected by the connecting waveguide cavity. Each straight waveguide cavity has a narrow waveguide side defined in its cross-section. The radiating element is disposed on a radiating surface facing the arrangement surface of the narrow waveguide side. The radiating element includes an array of inclined slots, each inclined slot having an inclined angle relative to the centerline of the narrow waveguide side. Each straight waveguide cavity has a plurality of inclined slots spaced at intervals along the longitudinal direction on the radiating surface.

[0005] In a preferred embodiment, in the array of inclined slots, at least some of the inclined slots located in the same row along the extension direction have different inclination angles, and the waveguide slot antenna radiates more power at the middle position than at the two sides along the extension direction.

[0006] In a preferred embodiment, in the array of inclined slots, the inclination angles of multiple inclined slots located in the same column along the longitudinal direction are at least partially different.

[0007] In a preferred embodiment, in the array of inclined slots, at least some of the inclined slots located in the same column along the longitudinal direction have different inclination angles, and the waveguide slot antenna radiates more power at the middle position than at the two sides along the longitudinal direction.

[0008] In a preferred embodiment, in the array of inclined slots, the inclination angles of multiple inclined slots located in the same row along the extension direction are at least partially different.

[0009] In a preferred embodiment, in the array of inclined slots, each inclined slot is defined as... θ ij ， i represents the row where the tilted slot is located, and j represents the column where the tilted slot is located. The tilt angles of the tilted slots in the i-th row and the tilted slots in the j-th column are at least partially different, and the waveguide slot antenna radiates more power at the middle position along the extension direction than at the two sides, and the waveguide slot antenna radiates more power at the middle position along the longitudinal direction than at the two sides.

[0010] As a preferred embodiment, each inclined gap θ ij The tilt angle is determined based on the radiation excitation value of the tilted slot; the radiation excitation value of each tilted slot in the array is obtained by the following formula: ; in, In the formula sidelobe Indicates the sidelobe level ；n This indicates the number of linear waveguide cavities with inclined slots; f (x) This is expressed as a function of the antenna low sidelobe synthesis method; In the formula, m represents the number of inclined slots set along the longitudinal direction on the radiating surface of each linear waveguide cavity; V si It is represented as the equivalent matrix of the normalized gap excitation values ​​along the extension direction; V sj It is represented as the equivalent matrix of the normalized gap excitation values ​​along the longitudinal direction; V ij It is represented as a matrix of the excitation values ​​of the inclined slots on the radiating element.

[0011] In a preferred embodiment, the spacing between two adjacent inclined gaps located on the same row in the extending direction is λ.l / 4~λ l , λ l It is expressed as spatial wavelength, with the unit being meters (m).

[0012] In a preferred embodiment, the spacing between two adjacent inclined gaps located in the same column in the longitudinal direction is approximately λ. g / 2,λ g It is expressed as the waveguide wavelength, with the unit being meters (m).

[0013] In a preferred embodiment, the slow wave structure includes a first slow wave line layer and a second slow wave line layer. The first slow wave structure is disposed on the first slow wave line layer, and the second slow wave structure is disposed on the second slow wave line layer. The slow wave structure is formed by connecting the first slow wave structure and the second slow wave structure.

[0014] In a preferred embodiment, the plurality of linear waveguide cavities are arranged at intervals along the extension direction, and the slow wave structure has two opposite ends in the extension direction, one end of which is provided with a feed port and the other end of which is provided with a load port.

[0015] In a preferred embodiment, the connecting waveguide cavity includes a first connecting waveguide cavity and a second connecting waveguide cavity. The straight waveguide cavity has a first end and a second end in its longitudinal direction. The first end is connected to the first connecting waveguide cavity, and the second end is connected to the second connecting waveguide cavity. Both the first and second connecting waveguide cavities include a serpentine waveguide portion, and at least one of the first and second connecting waveguide cavities further includes a coupling portion connected to the serpentine waveguide portion. The coupling portion extends along a direction perpendicular to or inclined to the layout surface in the straight waveguide cavity, so that the layout surface in the serpentine waveguide portion of the first and / or second connecting waveguide cavities is not on the same plane as the layout surface in the straight waveguide cavity.

[0016] In a preferred embodiment, the slow wave structure includes: a first metal layer, an intermediate layer, and a second metal layer stacked sequentially; a linear waveguide cavity is disposed on the first metal layer; the intermediate layer is provided with a coupling port; and a serpentine waveguide portion of at least one of the first connecting waveguide cavity and the second connecting waveguide cavity is disposed on the second metal layer, and the serpentine waveguide portion located on the second metal layer is connected to the linear waveguide cavity through the coupling port.

[0017] In a preferred embodiment, one of the serpentine waveguide portion of the first connecting waveguide cavity and the serpentine waveguide portion of the second connecting waveguide cavity is disposed on the second metal layer, and the other is disposed on the first metal layer; or, both the serpentine waveguide portions of the first connecting waveguide cavity and the second connecting waveguide cavity are disposed on the second metal layer.

[0018] An antenna array comprising the waveguide slot frequency-scanning antenna described in any one of the claims.

[0019] A detection device includes an antenna array for transmitting detection signals and / or receiving return signals of the detection signals, said antenna array including any of the waveguide slot antennas described above.

[0020] An information system, characterized in that it includes a detection device and a signal processing device. The detection device includes a radio frequency front-end assembly and an antenna array; the detection device is used to detect a target by transmitting a detection signal based on frequency scanning and receiving a return signal of the detection signal; The radio frequency front-end component includes at least one of a signal amplification module, a mixing module, and a filtering module; the radio frequency front-end component is used to preprocess the probe signal before transmission and to preprocess the returned signal of the probe signal after reception. The antenna array includes any one of the waveguide slot antennas described above, and the antenna array is used to transmit a detection signal and / or receive a return signal of the detection signal; The signal processing device includes a processing and analysis module; the signal processing device is used to obtain target detection information based on the detection signal and the return signal, the detection information including one or more of the target's distance information, position information and spatial information.

[0021] Beneficial effects: The waveguide slot antenna provided in this application has its radiating element located on the radiating surface facing the narrow side of the waveguide. Compared to the wide side of the waveguide, the narrow side has a smaller side length. Even if the spacing g between adjacent waveguide elements is greater than 0.5 mm due to manufacturing limitations, the spacing between the radiating slots on two adjacent waveguide elements on the slow wave structure can be controlled, thereby effectively eliminating grating lobes, shaping the beam, and improving the antenna gain.

[0022] Furthermore, by setting multiple inclined slots in the longitudinal direction of the linear waveguide cavity, the effective aperture area of ​​the antenna radiating surface can be increased, thereby effectively reducing the beamwidth and making it point at an effective angle.

[0023] The waveguide slot antenna provided in this application embodiment has at least one coupling portion in the first connecting waveguide cavity and the second connecting waveguide cavity connected to the straight waveguide cavity. The coupling portion extends obliquely or perpendicularly to the layout surface inside the straight waveguide cavity, so that the layout surface inside the serpentine waveguide portion of the first connecting waveguide cavity and / or the second connecting waveguide cavity is not on the same plane as the layout surface inside the straight waveguide cavity. That is, the straight waveguide cavity is connected to only one serpentine waveguide portion in the longitudinal direction or there is no serpentine waveguide portion in the longitudinal direction, thereby reducing the size of the entire slow wave structure in the longitudinal direction while meeting the large-angle scanning requirements.

[0024] When arranging the antenna array, the height of the entire antenna array in the longitudinal direction can also be reduced, thereby achieving miniaturization and compactness of the antenna system.

[0025] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the present invention can be adopted. It should be understood that the scope of the embodiments of the present invention is not limited thereto.

[0026] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0027] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 The diagram shown is a schematic of a slow-wave serpentine waveguide structure provided by the prior art; Figure 2 The diagram shows a schematic of the wide side and narrow side of a waveguide provided by the prior art; Figure 3 The figure shown is a schematic diagram of the planar structure of a waveguide slot antenna provided in an embodiment of this application; Figure 4 The diagram shown is a schematic diagram of the assembly structure of a slow-wave structure of a waveguide slot antenna provided in an embodiment of this application; Figure 5 As shown Figure 4 A structural diagram from another perspective; Figure 6 The diagram shown is an assembly structure schematic of another slow-wave structure of a waveguide slot antenna provided in an embodiment of this application; Figure 7 The diagram shown is a schematic diagram of a radiating element in a waveguide slot antenna according to an embodiment of this application; Figure 8(a) shows the distribution curve of the slot voltage along the extension direction of the waveguide slot antenna in the embodiment of this application; Figure 8(b) shows the normalized admittance diagram of the waveguide element along the extension direction of the waveguide slot antenna in the embodiment of this application. Figure 9 The image shown is a large-angle frequency scanning pattern of the waveguide slot antenna in the extension direction according to an embodiment of this application. Figure 10 The image shown is a large-angle frequency scanning pattern of the waveguide slot antenna in the vertical direction according to an embodiment of this application. Figure 11 The figure shown is a three-dimensional structural diagram of a slow wave structure provided in an embodiment of this application; Figure 12 The figure shown is a three-dimensional structural schematic diagram of another slow-wave structure provided in an embodiment of this application; Figure 13 The image shows a... Figure 12 A schematic diagram of a waveguide slot antenna with a slow-wave structure; Figure 14 The image shows a... Figure 11 A planar schematic diagram of a waveguide slot antenna with a slow-wave structure; Figure 15 The diagram shown is a structural block diagram of the information system provided in an embodiment of this application; Figure 16 The diagram shown is a structural block diagram of the detection device provided in an embodiment of this application; Figure 17 The diagram shown is a structural block diagram of the signal processing device provided in an embodiment of this application.

[0030] Explanation of reference numerals in the attached figures: A. Longitudinal direction; B. Extension direction; C. Thickness direction; a. Wide side of waveguide; b. Narrow side of waveguide; 10', Straight waveguide segment; 20', Connecting waveguide segment; 100. Slow-wave structure; 1. First metal layer; 10. Linear waveguide cavity; 11. Radiation surface; 111. Radiation element; 12. Feed port; 13. Load port; 2. Second metal layer; 20. Serpentine waveguide section; 21. First connecting waveguide cavity; 22. Second connecting waveguide cavity; 23. Coupling section; 3. Intermediate layer; 30. Coupling port; 40 / 40', Layout surface; 41, First slow wave line layer; 411, First slow wave structure; 42, Second slow wave line layer; 422, Second slow wave structure; 5, Third metal layer; 200. Information system; 210. Detection device; 211. Radio frequency front-end component; 2111. Signal amplification module; 2112. Mixing module; 2113. Filtering module; 212. Antenna array; 220. Signal processing device; 221. Processing and analysis module. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solutions of this utility model, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0032] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or may be interposed with another element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] In waveguide slot scanning antennas with large scanning angles, slow wave structures are generally used to achieve large-angle scanning. The slow wave structure usually adopts a serpentine waveguide structure, which can be composed of straight waveguide segments and connecting waveguide segments.

[0035] Waveguide structures are typically three-dimensional structures. Common waveguide structures include rectangular waveguides, which have a rectangular cross-section with a wide side 'a' and a narrow side 'b'. Current waveguide structures are usually deployed in electronic devices with the wide side 'a' as the base surface. This base surface can be called the waveguide deployment surface, and the surfaces facing each other are used as the radiating surfaces for radiation.

[0036] The plane on which the waveguide is laid, or the plane closest to the laid-out plane (or the plane facing the slotted / radiating surface), can be called the waveguide's laying surface. For example... Figure 2 As shown, when the device is installed on the bottom surface of the wide side a, the installation surface 40 is the bottom surface of the wide side a, and the surface facing the installation surface 40 is the radiating surface (the opening is not shown); when the device is installed on the bottom surface of the narrow side b, the installation surface 40' is the bottom surface of the narrow side b, and the surface facing the installation surface 40' is the radiating surface (the opening is not shown).

[0037] Generally speaking, within the deployment plane of a serpentine waveguide, the transverse direction in which the serpentine waveguide meanders is called the extension direction. Figure 1 The direction B in the plane shows the extension direction of the serpentine waveguide structure. The direction perpendicular to the extension direction in the plane is called the longitudinal direction A. The serpentine waveguide structure includes several straight waveguide segments and connecting waveguide segments. That is, the serpentine waveguide structure includes straight waveguide segments and connecting waveguide segments. The straight waveguide segments can extend along the longitudinal direction A and are roughly straight. The connecting waveguide segments have "turning parts" and the two ends of the straight waveguide segments are connected to the connecting waveguide segments respectively.

[0038] A gap is left between two adjacent straight waveguide segments to separate them and avoid signal interference. Several adjacent straight waveguide segments are connected end-to-end by connecting waveguide segments to form an extended serpentine waveguide structure. A straight waveguide segment and its connected connecting waveguide segment can be defined as a serpentine waveguide unit. Each serpentine waveguide unit has a radiating slot on its radiating surface facing the deployment surface.

[0039] like Figure 1 The serpentine waveguide structure shown is in planar form, comprising a straight waveguide segment 10' and a connecting waveguide segment 20'. Both ends of the straight waveguide segment 10' are connected to a connecting waveguide segment 20', and one end of the connecting waveguide segment 20' is then connected to the straight waveguide segment 10' of the adjacent waveguide unit, thus forming the serpentine waveguide structure. Figure 1 The connecting waveguide segment 20' shown has a bend, which can have an arc-shaped structure, thereby reducing the voltage standing wave ratio of the serpentine waveguide and increasing the antenna gain while reducing dissipation.

[0040] Alternatively, the turning portion of the connecting waveguide section of the serpentine waveguide structure can have a rectangular structure, with both ends of the straight waveguide section connected to the rectangular connecting waveguide section. One end of the rectangular connecting section is then connected to the straight waveguide section of the adjacent waveguide unit, thereby forming the serpentine waveguide structure. Alternatively, the shape of the connecting waveguide section of the serpentine waveguide is not limited to the above shapes; its turning portion can have an arc shape, a rectangle, or at least one of other possible shapes.

[0041] The aforementioned straight waveguide segment and the surrounding boundaries connecting the waveguide segments form a cavity structure, serving as a transmission channel for electromagnetic waves. For example... Figure 2 As shown, the waveguide cavity structure of the straight waveguide segment has a rectangular cross-section, on which a wide waveguide side a and a narrow waveguide side b are defined, wherein the dimension of the wide waveguide side a is larger than the dimension of the narrow waveguide side b. It should be noted that the terms "wide waveguide side a" and "narrow waveguide side b" are well-known technical terms in the art. Since this specification introduces these two basic concepts of wide waveguide side and narrow waveguide side, it should be understood that the cross-section of the waveguide cavity structure mentioned in this specification is a rectangular cross-section.

[0042] Based on the principle of electromagnetic radiation, a slot is formed in the waveguide wall. When the slot cuts off the surface current lines on the waveguide wall, part of the surface current bypasses the slot, while the other part flows through the slot in the original direction as a displacement current. This displacement current is the source of radiation generated by the slot along the radiation direction into the outer space. The radiation direction is perpendicular to both the longitudinal direction A and the extension direction B. The slot type varies depending on its location. When the slot is located on the wide side a of the waveguide, it can be a longitudinally offset slot, which cuts the transverse current of the wide side. When the slot is located on the narrow side b of the waveguide, it can be an inclined slot, which also cuts the transverse current of the narrow side b. The longitudinally offset slot is set along the longitudinal direction of the wide side of the waveguide cavity in the straight waveguide segment, offset from the centerline of the wide side by a certain distance. By adjusting the offset from the centerline, the radiation intensity of the slot can be adjusted, thus affecting the antenna radiation or scanning effect. The inclined slot is set along the narrow side of the waveguide cavity of the straight waveguide section and has an inclined angle with the center line of the narrow side. By adjusting the inclined angle, the radiation intensity can be adjusted, thereby affecting the antenna radiation or scanning effect.

[0043] In existing technologies, the radiating surface of a serpentine waveguide structure typically corresponds to the plane containing the wide side of the waveguide rather than the plane containing the narrow side. By creating slots on the radiating surface corresponding to the wide side of the waveguide, a larger radiating aperture and a lower profile can be achieved. However, this structure is difficult to apply in high-frequency radiation, especially in high-frequency scanning applications.

[0044] This invention provides a waveguide slot antenna, such as Figures 3 to 14As shown, the waveguide slot antenna includes a slow-wave structure 100 and a radiating element 111. The slow-wave structure 100 includes a plurality of straight waveguide cavities 10 and a connecting waveguide cavity. The plurality of straight waveguide cavities 10 are arranged at intervals along the extension direction B, and adjacent two straight waveguide cavities 10 are connected by the connecting waveguide cavity. The straight waveguide cavity 10 defines a narrow waveguide side in its cross-section. The radiating element 111 is disposed on a radiating surface 11 facing the arrangement surface of the narrow waveguide side. The radiating element 111 includes inclined slots arranged in an array. The inclined slots have an inclined angle relative to the centerline of the narrow waveguide side. The straight waveguide cavity 10 is provided with a plurality of inclined slots at intervals along the longitudinal direction A on the radiating surface 11.

[0045] The "waveguide cavity" is formed by a solid boundary. The "waveguide cavity" can be formed by slotting or by injection molding. Specifically, the linear waveguide cavity corresponds to the cavity formed by the surrounding boundary of the linear waveguide segment mentioned earlier, and the connecting waveguide cavity corresponds to the cavity formed by the surrounding boundary of the connecting waveguide segments mentioned earlier. It is understood that although this specification... Figures 3 to 14 The illustrated connecting waveguide cavity has an arc-shaped bend structure, but other shapes, such as rectangles, arcs, or combinations thereof, can also be used to achieve this bend structure, and the scope of protection of this application is not limited thereto.

[0046] This application utilizes an inclined slot on the radiating surface 11 corresponding to the narrow side of the serpentine waveguide. Compared to the prior art where slots are opened on the radiating surface 11 corresponding to the wide side of the waveguide, this is more suitable for high-frequency radiation. The reason is that, due to the short wavelength of high-frequency radiation, to achieve a better radiation effect, the spacing between adjacent radiating slots along the extension direction B needs to be less than a predetermined condition, such as half the spatial wavelength. However, when slots are opened on the radiating surface 11 corresponding to the wide side of the waveguide, it is difficult to meet this predetermined condition due to limitations in manufacturing processes. Furthermore, since the narrow side of the waveguide is smaller than the wide side, even the spacing between adjacent waveguide units... g Even with a processing limitation greater than 0.5mm, the spacing between two adjacent radiating slots along the extension direction B of the slow-wave structure 100 can still be well controlled to not exceed a preset condition, thereby effectively eliminating grating lobes, shaping the beam, and improving antenna gain. For example... Figure 9 As shown, when the waveguide slot antenna scans at a large angle frequency in the extension direction, it can effectively achieve beam narrowing in the extension direction B.

[0047] Therefore, when the plurality of linear waveguide cavities 10 are arranged at intervals along the extension direction B, the spacing between two adjacent inclined slots 111 in the extension direction B can be less than a preset condition. Here, each inclined slot has a center point in its own extension direction, and the spacing between two adjacent inclined slots represents the distance between the center points of the two adjacent inclined slots.

[0048] For waveguide slot antennas, the minimum resolvable beam angle is a key parameter measuring the antenna's ability to distinguish two adjacent targets in space. It is an important manifestation of the antenna's "spatial resolution capability"; the smaller the value, the stronger the antenna's resolution capability. According to the formula for the minimum resolvable beam angle: ; In the above formula, Represented as the smallest resolvable angle, in degrees; λ l The wavelength is expressed in meters (m); D represents the effective aperture size of the antenna (length along the resolution direction), also in meters; k represents the beam quality factor (typically 0.8 to 1.5, determined by the antenna efficiency); where, N represents the number of slits; d represents the slit spacing in mm; α represents the beam scanning angle.

[0049] It is evident that a larger aperture along the resolution direction results in a smaller minimum resolvable angle, thus narrowing the beam and enabling the resolution of targets with smaller angular distances. Therefore, to obtain a narrow beam, by spaced multiple inclined slots along the longitudinal direction A on the radiating surface 11 of the linear waveguide cavity 10, the effective aperture size of the antenna along the longitudinal direction can be increased, thereby effectively reducing the beamwidth and improving directivity. Figure 10 As shown, the waveguide slot antenna provided in this application can effectively narrow the beam of the antenna in the longitudinal direction A by scanning the radiation pattern in the vertical direction (i.e., the longitudinal direction), thereby improving the antenna's directional capability.

[0050] In this specification, since the linear waveguide cavities 10 are arranged at intervals along the extension direction B, and each linear waveguide cavity 10 has an inclined slot on its radiation surface 11, the radiation units 111 are arranged in an array of inclined slots.

[0051] Generally speaking, on the radiating surface 11 of the linear waveguide cavity 10, if the spacing between two adjacent slots opened along the longitudinal direction A is approximately λ... g / 2, where the inclined slot has a center point along its own extension direction, and the spacing between two adjacent inclined slots represents the distance between the center points of two adjacent inclined slots. When electromagnetic waves propagate between multiple inclined slots on the waveguide unit, they travel at the waveguide wavelength λ. gFor transmission, when the distance between two adjacent slots is approximately λg / 2, the phase difference between the tilted slots is 180°. An additional 180° phase shift is needed between the adjacent slots to ensure in-phase excitation. For the tilted slots on the radiating surface 11 corresponding to the narrow side of the waveguide, using opposite tilt angles can achieve an additional 180° phase shift, thus satisfying in-phase excitation. Therefore, two adjacent tilted slots along the longitudinal direction A are roughly arranged in a figure-eight shape to present tilt angles with opposite phases.

[0052] The figure-eight distribution can be symmetrical. In a symmetrical figure-eight distribution, adjacent inclined slots have the same inclination angle relative to the centerline of the narrow side of the waveguide, but the inclination phases of adjacent inclined slots 111 differ by 180 degrees, thus forming a symmetrical figure-eight distribution in the inclination direction between adjacent inclined slots. The figure-eight distribution can also be asymmetrical. In an asymmetrical figure-eight distribution, the phases of adjacent inclined slots have a certain angular deviation relative to 180 degrees. This is because when the electromagnetic wave signal radiates outwards, it propagates along the waveguide unit. Each time the electromagnetic wave signal flows through a slot, part of its electromagnetic wave energy will radiate outwards through that slot, while the remaining electromagnetic wave energy continues to flow backwards, but the energy will gradually weaken. Therefore, by adjusting the inclination angle of the slots along the longitudinal direction A, the radiated energy of the electromagnetic wave can be changed. In this case, adjacent inclined slots along the longitudinal direction A form an asymmetrical figure-eight distribution.

[0053] The distance between two adjacent slits opened along the longitudinal direction A is approximately λ. g / 2 should be understood as in λ g Values ​​near / 2 can be λ. g / 4~3λ g / 4. For frequency-scanning antennas, the frequency of the electromagnetic wave input to the antenna can vary, and therefore the waveguide wavelength can also vary. When manufacturing waveguide slot antennas, this λ... g By taking the waveguide wavelength corresponding to a certain frequency, the spacing between two adjacent slits opened in the longitudinal direction A can be obtained.

[0054] In some implementations, such as Figure 3 and Figure 7 As shown, in order to improve the directivity of the beam in the extension direction B, the tilt angles of at least some of the tilted slots in the array of tilted slots located in the same row along the extension direction B can be different, and the waveguide slot antenna is required to have stronger radiation power at the middle position than at the two sides along the extension direction B.

[0055] Specifically, the tilt angles of adjacent tilted slots along the extension direction B can be different to make the antenna radiated power exhibit a radiation waveform that is strong in the middle and weak at both sides. The radiated power of the waveguide slot antenna along the extension direction B can be an effect where the power increases from both sides towards the middle, for example, a radiation waveform conforming to the Taylor synthesis method; or it can be a waveform with a decreasing waveform at both sides before increasing towards the middle, for example, a radiation waveform conforming to the Chebyshev synthesis method; or a radiation waveform conforming to the Fourier synthesis method; or other possible radiation waveforms conforming to the antenna's low sidelobe synthesis function. However, overall, the radiation waveform of the waveguide slot antenna shows that the radiated power at the middle position along the extension direction B is stronger than the radiated power at the sides.

[0056] like Figure 7 The radiating element 111 shown has at least partially different tilt angles for the tilted slots located in the same row along the extension direction B, specifically corresponding to the waveform of the required radiated power. In the array of tilted slots, the tilted slots in the same column, i.e., multiple tilted slots spaced apart along the longitudinal direction A corresponding to each waveguide element, are normalized to obtain a matrix of 1*n radiating elements 111, and the normalized slot excitation values ​​along the extension direction B satisfy the following formula: In the formula sidelobe Indicates the sidelobe level ；n This indicates the number of linear waveguide cavities with inclined slots; f (x) This is expressed as a function of the antenna low sidelobe synthesis method; V si It is represented as the equivalent matrix of the normalized gap excitation values ​​along the extension direction.

[0057] In a specific embodiment, as shown in FIG8(a), multiple inclined slots spaced apart along the longitudinal direction A are normalized, and then the Taylor synthesis method can be used to adjust the radiation energy of the inclined slots located in the same row along the extension direction B, thereby adjusting the tilt angle of each inclined slot according to the obtained radiation energy, so that the waveguide slot antenna has stronger radiation power at the middle position than at the two sides along the extension direction B.

[0058] In an array of inclined slots, the inclined slots in the same column, i.e., multiple inclined slots spaced apart along the longitudinal direction A corresponding to each waveguide element, are normalized. The normalized slot excitation values ​​along the extension direction satisfy the following formula: In the formula sidelobe Indicates the sidelobe level ；nThis indicates the number of linear waveguide cavities with inclined slots. V si It is represented as the equivalent matrix of the normalized gap excitation values ​​along the extension direction; The equivalent matrix of the relative excitation value of each waveguide element can be determined using the above formula. V Si According to the obtained V Si And through the following formula Then, the normalized admittance of the slot on each waveguide unit is obtained: ; ; ; In the formula, f i P represents the radiated power of the i-th waveguide element of the antenna, where i ∈ [0, n-1]; η represents the radiating efficiency of the radiating element; r P represents the total power radiated by all waveguide elements. in This represents the power input from the feed to the antenna; P represents the normalized admittance of the i-th waveguide element of the antenna; L This represents the power absorbed by the terminal load. After the excitation is fed in from the feed source, it will couple out a portion of the energy through the slots in each waveguide element and radiate it outward. Given the antenna radiation efficiency, the normalized admittance of the slots in each waveguide element can be obtained by working backward from the normalized admittance of the last waveguide element. This normalized admittance can represent the coupling coefficient of the corresponding normalized slot.

[0059] Then, the tilt angle of the normalized slot on each waveguide unit is obtained based on the normalized admittance, as shown in the following formula: In the above formula, 'a' represents the wide side dimension of the waveguide, in meters (m); 'b' represents the narrow side dimension of the waveguide, in meters (m). This indicates the waveguide wavelength, expressed in meters (m). Indicates spatial wavelength, in meters (m); The normalized tilt angle of the tilt slot in the i-th waveguide element of the antenna is expressed in degrees.

[0060] For example, when sidelobe=-30 and n=48, the gap excitation value is shown in Figure 8(a). V SiThe distribution curve is shown in Figure 8(b), where the horizontal axis represents the number of waveguide elements along the extension direction B, and the vertical axis represents the normalized slot excitation value corresponding to each antenna waveguide element. Then, the normalized admittance of the slot on each waveguide element is obtained, as shown in Figure 8(b).

[0061] For example, when n=5, the equivalent matrix obtained by calling the Taylor function is [0.6,0.85,1,0.85,0.6]; Since waveguide slot antennas do not release 100% of their energy through the slots when radiating outwards, when the efficiency of the radiating elements on the antenna needs to be 90%, f can be obtained according to the above formula. i [0.103,0.205,0.286,0.205,0.103] In this matrix, the final output energy of each normalized slot is as follows: 10.3% for the first normalized slot, 20.5% for the second normalized slot, 28.6% for the third normalized slot, 20.5% for the fourth normalized slot, and 10.3% for the fifth normalized slot. Thus, the total power radiated by all waveguide elements is 90.2%, with the remaining 9.8% absorbed by the load.

[0062] Then, by working backward from the normalized admittance of the slot in the last waveguide element, the normalized admittance of the slot in each waveguide element can be obtained: ① Admittance of the fifth normalized gap: 10.3 / 9.8 = 1.05; ② Admittance of the fourth normalized gap: 20.5 / (9.8+10.3) = 1.02; ③ Admittance of the third normalized gap: 28.6 / (9.8+10.3+20.5)=0.7; ④ Admittance of the second normalized gap: 20.5 / (9.8+10.3+20.5+28.6)=0.296; ⑤ Admittance of the first normalized gap: 10.3 / (9.8+10.3+20.5+28.6+20.5)=0.115; Then, the tilt angle of each normalized slot is obtained based on the normalized admittance. Since each waveguide element has multiple tilted slots spaced at intervals along the longitudinal direction A, the obtained tilt angles of the normalized slots can be further processed.

[0063] In one possible implementation, in the longitudinal direction A, multiple tilted slots located in the same column have the same tilt angle and form a symmetrical figure-eight distribution, so that the tilt angles of two adjacent tilted slots are 180 degrees out of phase. That is, the tilt angles of multiple tilted slots located on the i-th waveguide element are all the normalized tilt angles of the i-th waveguide element of the antenna.

[0064] Alternatively, in another possible implementation, in the array of inclined slots, the inclination angles of multiple inclined slots located in the same column along the longitudinal direction A are at least partially different. In this embodiment, if the inclination angles of inclined slots located in the same column along the longitudinal direction A are at least partially different, then adjacent inclined slots have a certain angular deviation relative to 180 degrees, forming an asymmetrical figure-eight distribution.

[0065] In this embodiment, for example, the tilt angles of at least some of the tilted slots located in the same column along the longitudinal direction A are different. The angle of each tilted slot in the same column can be adjusted according to the normalized tilt angle of the tilted slot so that the waveguide slot antenna has stronger radiation power in the middle position than in the two sides along the longitudinal direction.

[0066] In this embodiment, the tilt angles of the inclined slots located in the same column along the longitudinal direction A may all be different. Based on the foregoing description, as the electromagnetic wave signal propagates along the waveguide unit, its energy gradually weakens each time it passes through a slot. Therefore, adjusting the tilt angle of the radiating slots along the longitudinal direction A—for example, the tilt angle can change the radiated energy of the electromagnetic wave—results in different tilt angles along the longitudinal direction A. For instance, along the transmission direction of the electromagnetic wave signal, the tilt angle of the inclined slots increases sequentially, but its average value is the normalized tilt angle of the inclined slots.

[0067] In this specification, the distance between two adjacent inclined slots located on the same row in the extending direction B is λ. l / 4~λ l , λ l It is expressed as spatial wavelength, with the unit being meters (m).

[0068] In the field of beam scanning, to eliminate beam grating lobes, the beam spacing d theoretically needs to satisfy the following conditions: d≤ d max ； in, d max The maximum spacing value for eliminating grid lobes, in meters; θ m This is the maximum scanning angle, in degrees. λ l λ is the spatial wavelength, in meters (m); n is the number of waveguide elements, i.e., the number of linear waveguide cavities with inclined slots. From the above formula, it can be seen that, when other parameters remain constant, the larger the maximum scanning angle, the smaller the maximum spacing value for eliminating grating lobes.

[0069] Assuming the maximum scanning angle reaches ±90 degrees, and the number of waveguide elements is sufficiently large, i.e., (1-1 / n) is close to equal to 1, then... d max Approximately λ l / 2 Therefore, the spacing between adjacent waveguide elements is no greater than [missing value]. λ l / 2 At the same time, it can reduce the generation of grating lobes during large-angle scanning, effectively shape the beam, and further improve the antenna gain.

[0070] When the operating frequency is high, the corresponding spatial wavelength is small. d max The wavelength is smaller; however, at lower operating frequencies, the corresponding spatial wavelength is larger. d max Larger. Based on the aforementioned... d max As can be seen from the formula, d max Compared to λ l The multiple is (1-1 / n) / (1+|sinθ) m |), where |sinθ m | takes values ​​from 0 to 1, where n is the number of waveguide elements. The minimum value of n is 2, and theoretically, the maximum value of n can approach infinity. When the number of waveguide elements is very large and |sinθ m When | is 1, d max Approximately λ l / 2 When the number of waveguide elements is 2 and |sinθ m When | is 1, d max Approximately λ l / 4 When the number of array elements is very large and |sinθ m When | is 0, d max Approximately λ l However, this is a practically non-existent extreme case. In beam scanning, there should always be a certain scanning angle.

[0071] For example, if the scanning angle is ±90 degrees, |sinθ m When | is 1, and the number of waveguide elements is large, the maximum spacing between waveguide elements is approximately λ l / 2 For example, if the scanning angle is ±90 degrees, |sinθm When | is 1, and the number of waveguide elements is 2, the maximum spacing between waveguide elements is approximately λ l / 4 For example, if the scanning angle is ±10 degrees, |sinθ m When the number of waveguide elements is small, the maximum spacing between waveguide elements is approximately 0.17. λ l .

[0072] In some implementations, in order to improve the directivity of the beam in the longitudinal direction A, at least some of the inclined slots in the array arrangement located in the same column along the longitudinal direction A have different inclination angles, and the waveguide slot antenna radiates more power at the middle position than at the two sides along the longitudinal direction A.

[0073] The tilt angles of adjacent tilted slots along the longitudinal direction A can be different to make the antenna radiated power exhibit a radiation waveform that is strong in the middle and weak at the sides. Specifically, the radiated power of the waveguide slot antenna along the longitudinal direction A can be an effect where the power increases from the sides towards the middle, for example, a radiation waveform conforming to the Taylor synthesis method; or a waveform where the power decreases at the sides before increasing towards the middle, for example, a radiation waveform conforming to the Chebyshev synthesis method; or a radiation waveform conforming to the Fourier synthesis method; or other possible radiation waveforms conforming to the antenna's low sidelobe synthesis function. However, overall, the radiation waveform of the waveguide slot antenna shows that the radiated power at the middle position along the longitudinal direction A is stronger than the radiated power at the sides.

[0074] In an array of inclined slots, the inclined slots in the same row are normalized to obtain a matrix with radiating elements of m*1. The normalized slot excitation values ​​along the longitudinal direction satisfy the following formula: In the formula, m represents the number of inclined slots set along the longitudinal direction on the radiating surface of each linear waveguide cavity; V sj It is represented as the equivalent matrix of the normalized gap excitation values ​​along the longitudinal direction; In one specific embodiment, Taylor synthesis can be used to adjust the radiated energy of multiple tilted slots located in the same column along the longitudinal direction A. This allows adjustment of the tilt angle of each tilted slot based on the obtained radiated energy, so that the waveguide slot antenna exhibits stronger radiated power at the central position than at the two sides along the longitudinal direction A. The specific method of using Taylor synthesis can be found in the preceding description and will not be repeated here.

[0075] In one possible implementation, multiple inclined slots located on the same row in the extension direction B have the same inclination angle, and the inclination angles of two adjacent inclined slots are 180 degrees out of phase.

[0076] Alternatively, in another possible implementation, in the array of inclined slots, the inclination angles of multiple inclined slots located in the same row along the extension direction B are at least partially different. In this embodiment, if the inclination angles of inclined slots located in the same row along the extension direction B are at least partially different, then there is a certain angular deviation between adjacent inclined slots relative to 180 degrees.

[0077] In this embodiment, for example, the tilt angles of at least some of the tilted slots on the same row along the extension direction B are different. The angle of each tilted slot on the same row can be adjusted according to the normalized tilt angle of the tilted slot so that the waveguide slot antenna has stronger radiation power at the middle position than at the two sides along the extension direction B.

[0078] In this embodiment, the tilt angles of the inclined slots along the same row along the extension direction B may all be different. Based on the foregoing description, as the electromagnetic wave signal propagates along the waveguide unit, its energy gradually weakens each time it passes through a slot. Therefore, adjusting the tilt angle of the radiating slots along the extension direction B—for example, changing the radiated energy of the electromagnetic wave—results in different tilt angles along the extension direction B. For instance, as the electromagnetic wave signal propagates along the extension direction B, the tilt angles of the inclined slots increase sequentially, but their average value is the normalized tilt angle of the inclined slots.

[0079] In one possible implementation, in the array of inclined slots, each inclined slot is defined as... θ ij ， i represents the row where the tilted slot is located, and j represents the column where the tilted slot is located. The tilt angles of the tilted slots in the i-th row and the tilted slots in the j-th column are at least partially different, and the waveguide slot antenna radiates more power at the middle position along the extension direction B than at the two sides, and the waveguide slot antenna radiates more power at the middle position along the longitudinal direction A than at the two sides.

[0080] In one specific embodiment, the radiated energy of the tilted slots located in the same row along the extension direction B and the radiated energy of the tilted slots located in the same column along the longitudinal direction A can be adjusted by using a double antenna low sidelobe synthesis method function. This results in the waveguide slot antenna exhibiting stronger radiated power at the middle position along the extension direction B than at the two sides, and the waveguide slot antenna exhibiting stronger radiated power at the middle position along the longitudinal direction A than at the two sides.

[0081] Specifically, the tilt angle of each tilted slit θij is determined based on the radiation excitation value of that tilted slit; The radiation excitation value of each inclined slit in the array of inclined slits is obtained by the following formula: ; in, In the formula sidelobe Indicates the sidelobe level, in units of dB; n This indicates the number of linear waveguide cavities with inclined slots; f (x) This is expressed as a function of the antenna low sidelobe synthesis method; In the formula, m represents the number of inclined slots set along the longitudinal direction on the radiating surface of each linear waveguide cavity; V si It is represented as the equivalent matrix of the normalized gap excitation values ​​along the extension direction; V sj It is represented as the equivalent matrix of the normalized gap excitation values ​​along the longitudinal direction; V ij This is represented as a matrix of the excitation values ​​of the inclined slots on the radiating element; Then, based on the obtained radiative excitation value of each inclined slit in the array of inclined slits, the radiative power of each inclined slit is obtained using the following formula: In the formula, f ij η represents the radiated power of the inclined slit, expressed in W; η represents the efficiency of the radiating element.

[0082] Therefore, in this embodiment, the equivalent matrix of the normalized slot excitation value of each waveguide element along the extension direction B is obtained by using the antenna low sidelobe synthesis method. V Si And the equivalent matrix of the normalized gap excitation value along the longitudinal direction A. V sj ， Then through An m*n matrix is ​​obtained, and the values ​​in the matrix represent the excitation values ​​of each inclined slot on the radiation element 111.

[0083] Furthermore, by using the excitation value of each inclined slot, the admittance of each slot can be obtained, thereby deriving the inclination angle of each slot.

[0084] In one possible implementation, such as Figures 4 to 6 As shown, the slow wave structure 100 includes a first slow wave line layer 41 and a second slow wave line layer 42. The first slow wave structure 411 is disposed on the first slow wave line layer 41, and the second slow wave structure 422 is disposed on the second slow wave line layer 42. The slow wave structure 100 is formed by connecting the first slow wave structure 411 and the second slow wave structure 422.

[0085] In this embodiment, both the first slow waveline layer 41 and the second slow waveline layer 42 have a plate-like structure. The straight waveguide cavity 10 and the solid boundary connecting the waveguide cavities are formed by the aforementioned plate-like structure. The first slow waveline layer 41 and the second slow waveline layer 42 are respectively provided with slots to form the first slow wave structure 411 and the second slow wave structure 422. The straight waveguide cavity 10 and the connecting waveguide cavity in the slow wave structure 100 are formed by the docking of the first slow wave structure 411 and the second slow wave structure 422. The waveguide cavity structure formed by docking has a wide waveguide side and a narrow waveguide side on its cross-section along its width direction. The wide waveguide side is formed by the docking of the first slow wave structure 411 and the second slow wave structure 422. An inclined slot is opened on the radiation surface 11 corresponding to the narrow waveguide side.

[0086] like Figure 4 and Figure 5 As shown, one of the first slow waveline layer 41 and the second slow waveline layer 42 can also serve as the radiating surface 11. For example, the second slow waveline layer 42 has a side facing the first slow waveline layer 41 and a side facing away from the first slow waveline layer 41, and the side facing away from the first slow waveline layer 41 is slotted as the radiating surface 11. Using this structure to enclose the waveguide cavity not only satisfies the requirement that the cross-section of the waveguide cavity has both a wide and narrow waveguide side, but also allows the slow wave structure 100 to be as thin as possible, thereby reducing the volume of the waveguide slot antenna.

[0087] Or, such as Figure 6 As shown, the slow wave structure 100 may further include a third metal layer 5. The third metal layer 5, the second slow wave line layer 42, and the first slow wave line layer 41 are stacked sequentially. The second slow wave structure 422 on the second slow wave line layer 42 is a slot that penetrates the plate-like structure. The radiation surface 11 is located on the third metal layer 5.

[0088] Of course, in other possible implementations, the slow wave structure 100 may be provided on only one slow wave line layer, in which case the slow wave line layer needs to have sufficient thickness.

[0089] In this instruction manual, such as Figure 3 As shown, the plurality of linear waveguide cavities 10 are arranged at intervals along the extension direction B, and the slow wave structure 100 has two opposite ends in the extension direction B, one end of which is provided with a feed port 12, and the other end of which is provided with a load port 13.

[0090] Several straight waveguide cavities 10 are arranged at intervals along the extension direction B to form a straight waveguide cavity array. The straight waveguide cavity array is also provided with a feed port 12 to feed electromagnetic waves, and a load port 13 to absorb any remaining electromagnetic waves. It should be noted that the straight waveguide cavity 10 with the feed port 12 serves as the starting end of the slow-wave structure 100, with a connecting waveguide cavity only at one end of the straight waveguide cavity 10; similarly, the straight waveguide cavity 10 with the load port 13 serves as the ending end of the slow-wave structure 100, also with a connecting waveguide cavity only at one end of the straight waveguide cavity 10. Both ends of the straight waveguide cavity 10 located between the feed port 12 and the output port 13 are connected to a connecting waveguide cavity, and adjacent straight waveguide cavities 10 are connected end-to-end through connecting waveguide cavities to form a serpentine waveguide structure.

[0091] In one possible implementation, such as Figures 11 to 14 As shown, the connecting waveguide cavity includes a first connecting waveguide cavity 21 and a second connecting waveguide cavity 22. The straight waveguide cavity 10 has a first end and a second end in its longitudinal direction A. The first end is connected to the first connecting waveguide cavity 21, and the second end is connected to the second connecting waveguide cavity 22. Both the first connecting waveguide cavity 21 and the second connecting waveguide cavity 22 include a serpentine waveguide section 20. At least one of the first connecting waveguide cavity 21 and the second connecting waveguide cavity 22 further includes a coupling section 23 connected to the serpentine waveguide section 20. The coupling section 23 extends along a direction perpendicular to or inclined to the layout surface in the straight waveguide cavity 10, so that the layout surface in the serpentine waveguide section 20 of the first connecting waveguide cavity 21 and / or the second connecting waveguide cavity 22 is not on the same plane as the layout surface in the straight waveguide cavity 10.

[0092] The slow wave structure 100 provided in this application embodiment has at least one coupling portion 23 in the first connecting waveguide cavity 21 and the second connecting waveguide cavity 22 connected to the straight waveguide cavity 10. The coupling portion 23 extends obliquely or vertically relative to the layout surface in the straight waveguide cavity 10, so that the layout surface in the serpentine waveguide portion 20 of at least one of the first connecting waveguide cavity 21 and the second connecting waveguide cavity 22 is not on the same plane as the layout surface in the straight waveguide cavity 10. That is, the straight waveguide cavity 10 is connected to only one serpentine waveguide portion 20 in the longitudinal direction A or there is no serpentine waveguide portion 20 in the longitudinal direction A, thereby reducing the size of the entire slow wave structure in the longitudinal direction A while meeting the large-angle scanning requirements.

[0093] Even if the layout surface in the serpentine waveguide section 20 of at least one of the first connecting waveguide cavity 21 and the second connecting waveguide cavity 22 is not on the same plane as the layout surface in the straight waveguide cavity 10, the straight waveguide cavity 10 can still maintain the connection relationship through the coupling section 23, thereby reducing the height while still satisfying the transmission characteristics of the slow wave structure.

[0094] Please refer to the previous description for the definition of the layout surface. Typically, such as... Figure 1 The serpentine waveguide structure shown has a linear waveguide segment and a connecting waveguide segment connected in the longitudinal direction A within the layout plane of the serpentine waveguide structure, and located in the same layout plane (or their layout planes overlap). It is understood that when the layout planes of the serpentine waveguide section 20 and the linear waveguide cavity 10 are on the same plane, the serpentine waveguide section 20 and the linear waveguide cavity 10 are connected in the longitudinal direction A and arranged along the longitudinal direction A. However, when the layout plane within the serpentine waveguide section 20 and the layout plane within the linear waveguide cavity 10 are not on the same plane, the serpentine waveguide section 20 and the linear waveguide cavity 10 will no longer be arranged along the longitudinal direction A.

[0095] In order to prevent the serpentine waveguide section 20 and the straight waveguide cavity 10 from being arranged along the longitudinal direction A, the arrangement surface in the serpentine waveguide section 20 needs to be "folded back" relative to the arrangement surface in the straight waveguide cavity 10. In other words, the serpentine waveguide section 20 is "folded back" relative to the straight waveguide cavity 10.

[0096] In one possible implementation, the slow wave structure 100 includes: a first metal layer 1, an intermediate layer 3, and a second metal layer 2 stacked sequentially; a straight waveguide cavity 10 is disposed on the first metal layer 1; the intermediate layer 3 is provided with a coupling port 30; a serpentine waveguide portion 20 of the first connecting waveguide cavity 21 and / or the second connecting waveguide cavity 22 is disposed on the second metal layer 2; and the serpentine waveguide portion 20 located on the second metal layer 2 is connected to the straight waveguide cavity 10 through the coupling port 30.

[0097] Specifically, the first metal layer 1, the intermediate layer 3, and the second metal layer 2 can have plate-like structures. The solid boundary of the "cavity" is formed by the aforementioned plate-like structures. The first metal layer 1, the intermediate layer 3, and the second metal layer 2 are stacked sequentially. The first metal layer 1 and the second metal layer 2 have slots, which form the "cavity" by connecting with the intermediate layer 3 between the first metal layer 1 and the second metal layer 2. The "cavity" has opposing upper and lower surfaces and a side surface surrounding the upper and lower surfaces. Taking a linear waveguide cavity 10 as an example, one of the upper and lower surfaces of the linear waveguide cavity 10 is located on the first metal layer 1, which is the bottom surface of the slot on the first metal layer 1. The other of the upper and lower surfaces is located on the intermediate layer 3. The side surface of the linear waveguide cavity 10 is also located on the first metal layer 1, which is the side surface of the slot on the first metal layer 1.

[0098] In this embodiment, the first metal layer 1, the intermediate layer 3, and the second metal layer 2 can be combined to form the slow-wave structure 100 in the aforementioned embodiment. Since at least one of the first connecting waveguide cavity 21 and the second connecting waveguide cavity 22 is folded away from the straight waveguide cavity 10, the slow-wave structure 100 needs to be set as a multi-layer structure. At this time, both the first metal layer 1 and the second metal layer 2 need to have sufficient thickness to ensure that the waveguide cavity formed by the butt joint has a relatively wide and narrow waveguide side. In addition, the surface of the first metal layer 1 facing away from the intermediate layer 3 can also be slotted as a radiating surface 11 to provide a radiating element 111.

[0099] The intermediate layer 3 has a first surface and a second surface facing each other. The first surface faces the first metal layer 1, and the second surface faces the second metal layer 2. The coupling port 30 extends from the first surface to the second surface. The linear waveguide cavity 10 and the serpentine waveguide portion 20 located on the second metal layer 2 are connected at the coupling port 30 and form the coupling portion 23 near the coupling port 30.

[0100] The serpentine waveguide section 20 located on the second metal layer 2 is connected to the linear waveguide cavity 10 through a coupling port 30. The position of the coupling port 30 corresponds to the end position of the linear waveguide cavity 10 and the bottom position of the serpentine waveguide section 20. The coupling port 30 can be a hole opened from the first surface to the second surface of the intermediate layer 3. The end of the linear waveguide cavity 10 located on the first metal layer 1 can directly correspond to the hole, and the bottom of the serpentine waveguide section 20 located on the second metal layer 2 can also directly correspond to the hole.

[0101] Alternatively, the coupling port 30 may include: a hole extending from the first surface to the second surface of the intermediate layer 3, and a protrusion extending from the location of the hole toward the bottom end of the linear waveguide cavity 10 and / or the serpentine waveguide portion 20, the protrusion having a channel; the end of the linear waveguide cavity 10 located on the first metal layer 1 communicates with the serpentine waveguide portion 20 located on the second metal layer 2 through the protrusion and the hole.

[0102] The linear waveguide cavity 10 and the serpentine waveguide section 20 located on the second metal layer 2 form a coupling section 23 near the coupling port 30. That is, the coupling section 23 is formed by the first metal layer 1, the intermediate layer 3, and the second metal layer 2. Specifically, the linear waveguide cavity 10 is formed on the first metal layer 1, and the serpentine waveguide section 20 is formed on the second metal layer 2. The cavity structure located near the coupling port 30, formed by the sequential connection between the end of the linear waveguide cavity 10, the coupling port 30, and the serpentine waveguide section 20, is the coupling section 23.

[0103] In order to prevent leakage of electromagnetic waves when they are transmitted from the linear waveguide cavity 10 to the connecting waveguide cavity, the cavity structure of the coupling part 23 is sealed by the first metal layer 1, the intermediate layer 3 and the second metal layer 2.

[0104] One of the serpentine waveguide portion 20 connecting the first waveguide cavity 21 and the serpentine waveguide portion 20 connecting the second waveguide cavity 22 is disposed on the second metal layer 2, and the other is disposed on the first metal layer 1, such as... Figure 12 As shown, this is a structure with only one serpentine waveguide section 20 "back-folded".

[0105] Alternatively, both the serpentine waveguide portion 20 of the first connecting waveguide cavity 21 and the serpentine waveguide portion 20 of the second connecting waveguide cavity 22 are disposed on the second metal layer 2, such as... Figure 11 and Figure 13 As shown, both the serpentine waveguide section 20 connecting the first waveguide cavity 21 and the serpentine waveguide section 20 connecting the second waveguide cavity 22 are "back-folded". Compared to the method of only "back-folding" one serpentine waveguide section 20, the dimension H of the slow wave structure 100 in the longitudinal direction A will be reduced by the longitudinal extension length of the two serpentine waveguide sections 20. This specification also provides an antenna array including the waveguide slot antennas described above, and at least two of the waveguide slot antennas are spliced ​​along the longitudinal direction A to form an antenna array.

[0106] Specifically, along the longitudinal direction A, the arrangement surfaces of at least two of the waveguide slot antennas in the serpentine waveguide section 20 at the splicing position are not on the same plane as the arrangement surfaces in the straight waveguide cavity 10.

[0107] In this embodiment, when arranging the antenna array, the waveguide slot antenna with the back-folded serpentine waveguide section 20 can also reduce the height of the entire antenna array in the longitudinal direction A, thereby achieving miniaturization and compactness of the antenna system.

[0108] Furthermore, when the slow-wave structure 100 of at least two waveguide slot antennas is spliced ​​along the longitudinal direction A, it increases the number of radiating slots for the frequency-scanning antenna, thereby increasing the effective aperture size of the antenna and effectively reducing the beamwidth, improving the antenna's directivity and radiation capability. In this case, the spacing between adjacent radiating slots in the longitudinal direction A needs to meet certain conditions to ensure high gain.

[0109] For a conventional slow-wave structure, its length along the longitudinal direction A generally includes one straight waveguide cavity and two connecting waveguide cavities. The radiating slots are typically located on the radiating surfaces facing each other within the straight waveguide cavity. If two conventional slow-wave structures are spliced ​​together along the longitudinal direction A to form an antenna array, the presence of the serpentine waveguide section causes the spacing between adjacent radiating slots at the splicing location along the longitudinal direction A to fail to meet the distance requirement (greater than the required distance, for example, 3λ). This results in insufficient gain and affects the radiation performance.

[0110] Therefore, by folding the serpentine waveguide in the slow-wave structure back relative to the straight waveguide cavity, especially at the splicing position of two slow-wave structures, the straight waveguide cavity is connected to only one serpentine waveguide in the longitudinal direction A, or there is no serpentine waveguide in the longitudinal direction A. At the splicing position, the spacing between adjacent radiation slots in the longitudinal direction A can be reduced, thereby ensuring high gain.

[0111] This specification also provides an antenna array 212, including the waveguide slot antenna in any embodiment of this application. The antenna array 212 shown in this embodiment has the function of the waveguide slot antenna described in any of the above embodiments, and its implementation principle and technical effect are similar, so it will not be described again here.

[0112] This specification also provides a detection device 210, such as Figure 16 As shown, it includes an antenna array 212 for transmitting detection signals and / or receiving return signals of detection signals, the antenna array 212 including the waveguide slot antenna in any embodiment of this application.

[0113] This specification also provides an information system 200, such as Figures 15 to 17As shown, the system includes a detection device 210 and a signal processing device 220. The detection device 210 includes a radio frequency front-end assembly 211 and an antenna array 212. The detection device 210 is used to detect a target by transmitting a frequency-scanned detection signal and receiving a return signal of the detection signal. The radio frequency front-end assembly 211 includes at least one of a signal amplification module 2111, a mixing module 2112, and a filtering module 2113. The radio frequency front-end assembly 211 is used to preprocess the detection signal before transmission and to preprocess the return signal of the detection signal after reception. The antenna array 212 includes the frequency-scanned antenna 200 and is used to transmit the detection signal and / or receive the return signal of the detection signal. The signal processing device 220 includes a processing and analysis module 221. The signal processing device 220 is used to obtain target detection information based on the detection signal and the return signal. The detection information includes one or more of the target's distance information, position information, and spatial information.

[0114] The preprocessing of the detection signal by the radio frequency front-end component 211 before transmission may include: the signal amplification module 2111 amplifies the detection signal to obtain an amplified detection signal, and transmits the amplified detection signal to the mixing module 2112. The mixing module 2112 receives the amplified detection signal from the signal amplification module 2111, performs mixing on the amplified detection signal to obtain a mixed signal, and transmits the mixed signal to the filtering module 2113. The filtering module 2113 receives the mixed signal and filters it. Alternatively, the filtering module 2113 may first filter the detection signal to obtain a filtered detection signal, then transmit the filtered detection signal to the signal amplification module 2111. The signal amplification module 2111 receives the filtered detection signal from the filtering module 2113, amplifies it, and then the mixing module 2112 performs mixing on the amplified detection signal to obtain a mixed signal.

[0115] The radio frequency front-end component 211 is used to perform preprocessing on the received return signal of the probe signal. The preprocessing process of the probe signal described above is referred to in the specification and will not be repeated here.

[0116] In the embodiments provided in this application, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interfaces, devices, or modules, and may be electrical, mechanical, or other forms.

[0117] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of the embodiments of this application, depending on actual needs.

[0118] Furthermore, the functional modules in the various embodiments of this application can be integrated into one processing unit, or each module can exist physically separately, or two or more modules can be integrated into one unit. The unit composed of the above modules can be implemented in hardware or in the form of hardware plus software functional units.

Claims

1. A waveguide slot antenna, characterized in that, The antenna includes a slow-wave structure and a radiating element. The slow-wave structure includes a plurality of straight waveguide cavities and a connecting waveguide cavity. The plurality of straight waveguide cavities are arranged at intervals along the extension direction, and adjacent two straight waveguide cavities are connected by the connecting waveguide cavity. The straight waveguide cavity defines a narrow waveguide side in its cross-section. The radiating element is disposed on a radiating surface facing the arrangement surface of the narrow waveguide side. The radiating element includes an array of inclined slots. The inclined slots have an inclined angle relative to the centerline of the narrow waveguide side. Each straight waveguide cavity has a plurality of inclined slots spaced at intervals along the longitudinal direction on the radiating surface.

2. The waveguide slot antenna as described in claim 1, characterized in that, In the array of inclined slots, at least some of the inclined slots in the same row along the extension direction have different inclination angles, and the waveguide slot antenna has stronger radiation power at the middle position than at the two sides along the extension direction.

3. The waveguide slot antenna as described in claim 2, characterized in that, In the array of inclined slots, the inclination angles of multiple inclined slots located in the same column along the longitudinal direction are at least partially different.

4. The waveguide slot antenna as described in claim 1, characterized in that, In the array of inclined slots, at least some of the inclined slots located in the same column along the longitudinal direction have different inclination angles, and the waveguide slot antenna radiates more power at the middle position than at the two sides along the longitudinal direction.

5. The waveguide slot antenna as described in claim 4, characterized in that, In the array of inclined slots, the inclination angles of multiple inclined slots located in the same row along the extension direction are at least partially different.

6. The waveguide slot antenna as described in claim 1, characterized in that, In the array of inclined slots, each inclined slot is defined as θ. ij , i represents the row where the tilted slot is located, j represents the column where the tilted slot is located, wherein the tilt angles of the tilted slots in the i-th row and the tilted slots in the j-th column are at least partially different, and satisfy the condition that the radiated power of the waveguide slot antenna at the middle position along the extension direction is stronger than the radiated power at the two sides, and the radiated power of the waveguide slot antenna at the middle position along the longitudinal direction is stronger than the radiated power at the two sides.

7. The waveguide slot antenna as described in claim 6, characterized in that, Each inclined gap θ ij The tilt angle is determined based on the radiation excitation value of the tilted slot; The radiation excitation value of each inclined slit in the array of inclined slits is obtained by the following formula: V ij =V sj ·V si ; in, In the formula, sidelobe represents the sidelobe level; n represents the number of linear waveguide cavities with tilted slots; f (x) This is expressed as a function of the antenna low sidelobe synthesis method; In the formula, m represents the number of inclined slots set along the longitudinal direction on the radiating surface of each linear waveguide cavity; V si Represented as the equivalent matrix of normalized gap excitation values ​​along the extension direction; V sj Represented as the equivalent matrix of normalized gap excitation values ​​along the longitudinal direction; V ij It is represented as a matrix of the excitation values ​​of the inclined slots on the radiating element.

8. The waveguide slot antenna as described in claim 1, characterized in that, The spacing between two adjacent inclined gaps on the same row in the extending direction is λ. l / 4~λ l , λ l It is expressed as spatial wavelength, with the unit being meters (m).

9. The waveguide slot antenna as described in claim 1, characterized in that, The spacing between two adjacent inclined gaps located in the same column in the longitudinal direction is approximately λ. g / 2,λ g It is expressed as the waveguide wavelength, with the unit being meters (m).

10. The waveguide slot antenna as described in claim 1, characterized in that, The slow wave structure includes a first slow wave line layer and a second slow wave line layer. The first slow wave structure is disposed on the first slow wave line layer, and the second slow wave structure is disposed on the second slow wave line layer. The slow wave structure is formed by connecting the first slow wave structure and the second slow wave structure.

11. The waveguide slot antenna as claimed in claim 1, characterized in that, The plurality of linear waveguide cavities are arranged at intervals along the extension direction. The slow wave structure has two opposite ends in the extension direction, one end of which is provided with a feed port and the other end of which is provided with a load port.

12. The waveguide slot antenna as described in claim 1, characterized in that, The connecting waveguide cavity includes a first connecting waveguide cavity and a second connecting waveguide cavity. The straight waveguide cavity has a first end and a second end in its longitudinal direction. The first end is connected to the first connecting waveguide cavity, and the second end is connected to the second connecting waveguide cavity. Both the first connecting waveguide cavity and the second connecting waveguide cavity include a serpentine waveguide portion. At least one of the first connecting waveguide cavity and the second connecting waveguide cavity further includes a coupling portion connected to the serpentine waveguide portion. The coupling portion extends along a direction perpendicular to or inclined to the layout surface in the straight waveguide cavity, so that the layout surface in the serpentine waveguide portion of the first connecting waveguide cavity and / or the second connecting waveguide cavity is not on the same plane as the layout surface in the straight waveguide cavity.

13. The waveguide slot antenna as described in claim 12, characterized in that, The slow-wave structure includes a first metal layer, an intermediate layer, and a second metal layer stacked sequentially. The linear waveguide cavity is disposed on the first metal layer. The intermediate layer is provided with a coupling port. At least one of the first connecting waveguide cavity and the second connecting waveguide cavity is disposed on the second metal layer, and the serpentine waveguide portion located on the second metal layer is connected to the linear waveguide cavity through the coupling port.

14. The waveguide slot antenna as described in claim 13, characterized in that, One of the serpentine waveguide portion of the first connecting waveguide cavity and the serpentine waveguide portion of the second connecting waveguide cavity is disposed on the second metal layer, and the other is disposed on the first metal layer; or, both the serpentine waveguide portions of the first connecting waveguide cavity and the second connecting waveguide cavity are disposed on the second metal layer.

15. An antenna array, characterized in that, Including the waveguide slot antenna as described in any one of claims 1-14.

16. A detection device, characterized in that, It includes an antenna array for transmitting a probe signal and / or receiving a return signal of the probe signal, the antenna array including a waveguide slot antenna as described in any one of claims 1-14.

17. An information system, characterized in that, Includes detection devices and signal processing devices. The detection device includes a radio frequency front-end assembly and an antenna array; the detection device is used to detect a target by transmitting a detection signal based on frequency scanning and receiving a return signal of the detection signal; The radio frequency front-end component includes at least one of a signal amplification module, a mixing module, and a filtering module; the radio frequency front-end component is used to preprocess the probe signal before transmission and to preprocess the returned signal of the probe signal after reception. The antenna array includes a waveguide slot antenna as described in any one of claims 1-14, the antenna array being used to transmit a detection signal and / or receive a return signal of the detection signal; The signal processing device includes a processing and analysis module; the signal processing device is used to obtain target detection information based on the detection signal and the return signal, the detection information including one or more of the target's distance information, position information and spatial information.

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