Multi-mode resonant waveguide slot antenna structure, waveguide radar and automobile

Abstract

The utility model provides a multimode resonant waveguide slot antenna structure and a waveguide radar, and the structure comprises a waveguide antenna which is provided with a waveguide channel; the waveguide channel comprises a waveguide input cavity, a waveguide power division cavity, a waveguide extension cavity and a multimode coupling window; the waveguide input cavity is vertically connected with the waveguide power division cavity; the plurality of waveguide extension cavities are in offset connection with the two ends of the waveguide power division cavity respectively, the waveguide power division cavity and the waveguide extension cavities are communicated through the multimode coupling window, and the opening of the multimode coupling window is smaller than the widths of the waveguide power division cavity and the waveguide extension cavities; and a plurality of radiation slots penetrate through the top of the waveguide channel. According to the utility model, the multimode coupling window is additionally arranged between the waveguide power division cavity and the waveguide extension cavity, and the opening width of the multimode coupling window is smaller than the widths of the waveguide power division cavity and the waveguide extension cavity, so that a dual-mode or multimode resonant mode is excited, and the bandwidth is greatly broadened; and the increase of manufacturing difficulty and cost caused by a complex power division structure or a power division network in the structural design is also avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of waveguide antenna, specifically, a kind of multi-mode resonant waveguide slot antenna structure and waveguide radar. BACKGROUND

[0002] At present, in the application of vehicle-mounted millimeter wave radar, waveguide antenna is paid more and more attention due to its low loss, high isolation and other advantages. The structure of waveguide antenna with radiation slot is: the waveguide cavity extends in a straight line, and the end is closed. The top surface (long side surface) of the waveguide cavity is provided with a radiation slot penetrating the waveguide antenna body. The radiation slot has an elongated radiation slot at the bottom layer, and the upper layer often has a step or a horn shape with increasing width. Each radiation slot has a central symmetric structure.

[0003] At present, the design of waveguide antenna product usually uses a slot array as the main radiation unit, and uses metal or surface metallized plastic as the basic material. Due to the short wavelength of millimeter wave and the high requirement for processing precision, in order to improve the bandwidth of signal transmission, a complex power division structure or power division network is usually set, which can lead to complex product structure, high manufacturing cost, and limited bandwidth improvement by changing the power division structure. Therefore, a new waveguide antenna structure is needed to further improve the bandwidth. SUMMARY

[0004] In view of the defects in the prior art, the purpose of the utility model is to provide a multi-mode resonant waveguide slot antenna structure and waveguide radar.

[0005] According to the multi-mode resonant waveguide slot antenna structure provided by the utility model, the waveguide antenna has a waveguide channel.

[0006] The waveguide channel includes a waveguide input cavity, a waveguide power division cavity, a waveguide extension cavity and a multi-mode coupling window.

[0007] The waveguide input cavity is connected vertically with the waveguide power division cavity. A plurality of waveguide extension cavities are connected with the two ends of the waveguide power division cavity respectively. The size of the connection between the waveguide power division cavity and the waveguide extension cavity is reduced to form a multi-mode coupling window. The multi-mode coupling window connects the waveguide power division cavity and the waveguide extension cavity. The opening of the multi-mode coupling window is smaller than the width of the waveguide power division cavity and the waveguide extension cavity.

[0008] A plurality of radiation slots are provided through the top of the waveguide channel.

[0009] Preferably, the opening width of the multi-mode coupling window is about 1 / 2 of the working wavelength.

[0010] Preferably, the H-plane center plane of the waveguide input cavity is a first center plane.

[0011] One end of the waveguide input cavity is a waveguide feed, the other end of the waveguide input cavity is in communication with the waveguide power division cavity, and the waveguide power division cavity is symmetrically arranged perpendicular to the first central plane.

[0012] Preferably, the H-plane central plane of the waveguide power division cavity is a second central plane, the H-plane central plane of the waveguide extension cavity is a third central plane, and the second central plane is offset parallel to the third central plane; a plurality of waveguide extension cavities are vertically and symmetrically arranged about the second central plane.

[0013] Preferably, the third central plane is parallel to the second central plane and offset in the direction of the waveguide input cavity.

[0014] Each waveguide extension cavity is spaced apart from the waveguide input cavity.

[0015] Preferably, the radiation slots are arranged as an even number and symmetrically distributed along the first central plane.

[0016] The first radiation slot on one side of the first central plane is located on the waveguide power division cavity; the remaining radiation slots are located on the waveguide extension cavities and are staggered on both sides of the third central plane.

[0017] Preferably, the central plane of the radiation slot is a fourth central plane, and each fourth central plane is parallel to the second central plane or the third central plane.

[0018] The offset amount of the fourth central plane parallel to the second central plane or the third central plane decreases in the direction away from the first central plane.

[0019] Preferably, the waveguide channel adopts a closed waveguide cavity.

[0020] Alternatively, the waveguide channel is formed by surrounding an antenna upper layer, an antenna lower layer, and a magnetic conductor unit, the magnetic conductor unit is located between the antenna upper layer and the antenna lower layer, and is in contact connection or non-contact connection with the antenna upper layer and the antenna lower layer, respectively.

[0021] The utility model provides a kind of waveguide radar, including the multimode resonant waveguide slot antenna structure.

[0022] The utility model provides a kind of car, including the waveguide radar.

[0023] Compared with the prior art, the utility model has the beneficial effects as follows:

[0024] 1. The waveguide antenna design provided by the utility model, a multimode coupling window is newly added between the waveguide power division cavity and the waveguide extension cavity, the opening width of the multimode coupling window is smaller than the width of the waveguide power division cavity and the waveguide extension cavity, the multimode coupling window excites a bimode or multimode resonance mode, and the bandwidth is greatly widened; the utility model provides a novel bandwidth widening structure, and the manufacturing difficulty and cost increase caused by the complex power division structure or power division network in the structural design are avoided.

[0025] 2. The waveguide antenna design provided by the utility model simplifies the design of the T-shaped power division structure, and it is not necessary to set a too much power division network structure or a complex matching or distribution structure; the structure design is simplified under the premise of ensuring the transmission performance.

[0026] 3. The waveguide antenna design provided by the utility model can effectively adjust the coupling strength between cavities by adjusting the position and width of the multimode coupling window structure, thereby adjusting the energy distribution of the radiation slot in the waveguide extension cavity, and then obtaining a more effective sidelobe level suppression effect.

[0027] 4. In the utility model, the waveguide extension cavity adopts an offset design, so that the central multiple radiation slots of the radiation slot array can be placed with a small offset or no offset, the antenna radiation pattern is more regular, the directivity is stronger, and the radiation far field phase is more stable.

[0028] 5. The energy coupling design of the waveguide cavity and the multimode coupling window in the utility model is different from the equal cross-sectional size transmission of a general waveguide, can realize multimode resonance, and effectively expand the super wide working bandwidth.

[0029] 6. The waveguide antenna design provided by the utility model realizes a larger working bandwidth, which is more than twice the target working bandwidth, thereby reducing the sensitivity to the manufacturing error of the waveguide structure size, and being more conducive to large-scale manufacturing.

[0030] 7. The waveguide antenna design provided by the utility model has excellent sidelobe suppression performance, and has a better suppression effect on the deterioration of the sidelobe level caused by the large difference in working wavelength under the high frequency or low frequency working mode in the band.

[0031] 8. The design of each waveguide structure such as the T-shaped power division structure and the resonant cavity structure in the utility model adopts a simple rectangular design, the structure is simple, the size is moderate, the production process is optimized, and the manufacturing cost is reduced.

[0032] 9. The waveguide antenna design provided by the utility model has a simple structure, minimizes the number of convergence parameters, is conducive to improving the efficiency of design iteration, and can quickly meet the technical requirements of different waveguide antenna application projects. BRIEF DESCRIPTION OF DRAWINGS

[0033] Other features, objects, and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments thereof as taken in conjunction with the accompanying drawings:

[0034] Figure 1 is a front perspective view of a waveguide channel in the present application;

[0035] Figure 2 is a front view of a waveguide cavity in the present application;

[0036] Figure 3 is a front view of a radiation slot in the present application;

[0037] Figure 4 is a front perspective view of a waveguide antenna (2 slots) in the present application;

[0038] Figure 5 is a front perspective view of a waveguide antenna (4 slots) in the present application;

[0039] Figure 6 is a front perspective view of a waveguide antenna (6 slots) in the present application;

[0040] Figure 7 is a front perspective view of a waveguide antenna (8 slots) in the present application;

[0041] Figure 8 is a perspective view of a waveguide antenna with a human-made magnetic conductor in the present application;

[0042] Figure 9 is a front view of a waveguide cavity and a radiation slot with a human-made magnetic conductor in the present application;

[0043] Figure 10 is a schematic diagram of S parameters of a waveguide antenna example in the present application, S parameters (Scatter parameters), i.e., scattering parameters, S(1,1) in the figure represents input return loss;

[0044] Figure 11 is a diagram of a waveguide antenna example in the present application, Azim is an azimuth angle, and Elev is an elevation angle.

[0045] Explanation of reference signs:

[0046] DETAILED DESCRIPTION

[0047] The present application will be described in detail below with specific embodiments. The following embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of changes and improvements can be made. These all belong to the protection scope of the present application.

[0048] The utility model provides a kind of multi-mode resonant waveguide slot antenna structure, the waveguide antenna structure has simplified T-shaped power division structure, under the premise of guaranteeing transmission and radiation performance, manufacturing difficulty is significantly reduced. By the bias connection of waveguide power division cavity and waveguide extension cavity, the smaller bias amount or no bias arrangement of multiple slots in the center of slot array is formed, the problems of poor antenna directivity and unstable far-field phase are solved. The misplacement connection of waveguide power division cavity and waveguide extension cavity forms multimode coupling window, the energy size coupled into waveguide extension cavity is adjusted, and ultra-low sidelobe level control is realized. The multi-mode resonance excited by radiation slot and multimode coupling window is formed, and ultra-wide working bandwidth is realized.

[0049] The structure of the waveguide antenna is further described in detail below.

[0050] Referring to Figures 1 to 3 The utility model discloses a kind of multi-mode resonant waveguide slot antenna structures, including waveguide antenna 1, and waveguide channel 2 is contained in waveguide antenna 1. Waveguide channel 2 includes waveguide input cavity 21, waveguide power division cavity 22 and waveguide extension cavity 23, and wave radiation slot 25 is vertically penetrated and arranged on waveguide channel 2.

[0051] The H face center plane of waveguide input cavity 21 is first center face 211, specifically, first center face 211 is respectively perpendicular to the center of waveguide input cavity H face top surface (referring to the drawing) and the center of H face bottom surface, and first center face 211 extends and is arranged along the direction of signal transmission in waveguide input cavity. Figure 6

[0052] Waveguide input cavity 21 one end is open, and is waveguide feed 212. Waveguide power division cavity 22 is symmetrically arranged perpendicularly to first center face 211, and is connected to form T-shaped power division structure with waveguide input cavity 21, and T-shaped power division structure profile is simple, and does not include traditional matching block, distribution block and other special structures. By simplified T-shaped power division structure, under the premise of meeting transmission and radiation performance, manufacturing process is optimized, and manufacturing difficulty is significantly reduced

[0053] The H face center plane of waveguide power division cavity 22 is second center face 221, and second center face 221 is perpendicular to first center face 211. The specific position structure of second center face 221 is similar to first center face 211, and is not described repeatedly.

[0054] ​Two waveguide extension cavities 23 are arranged in two directions of the second central plane 221 respectively, and connected with two ends of the waveguide power division cavity 22; the H plane central plane of the waveguide extension cavity 23 is the third central plane 231, which is parallel to the second central plane 221 and deviates from the waveguide input cavity 21 direction by a certain displacement. Two waveguide extension cavities 23 are arranged vertically and symmetrically to the second central plane 221. The specific position structure of the third central plane 231 is similar to that of the first central plane 211, and is not described here.

[0055] Two corners 241 are formed at the connection between the waveguide power division cavity 22 and each waveguide extension cavity 23, and two corners 241 form a multi-mode coupling window 24, the long side size of the multi-mode coupling window 24 is smaller than the long side size of the waveguide power division cavity 22 and the waveguide extension cavity 23. The interval between each waveguide extension cavity 23 and the waveguide input cavity 21 forms an interval 242. The multi-mode coupling window structure is introduced in the original regular waveguide shape, which can excite multi-mode resonance in the process of signal transmission, thereby forming several concave points on the signal standing wave curve, and further expanding the bandwidth.

[0056] Specifically, the multi-mode coupling window 24 introduces high-order mode to form a dual-mode or multi-mode coupling mechanism, which can realize energy exchange between modes, introduce additional transmission zeros, and thus realize higher order under the same volume, which helps to expand the bandwidth or improve the frequency response characteristics.

[0057] The dual-mode or multi-mode coupling design makes the multi-port waveguide cavity equivalent to multiple resonant units, and by cascading multiple dual-mode or multi-mode cavities, more poles can be realized without increasing the physical size, thereby expanding the passband bandwidth. The coupling coefficient between modes directly affects the bandwidth. Strengthening the coupling (such as increasing the size of the coupling window) can expand the bandwidth, and weakening the coupling can make the bandwidth narrower. Therefore, reasonable design of the coupling structure can realize bandwidth optimization.

[0058] An even number of radiation slots 25 are arranged above the waveguide cavity, and the radiation slots 25 are symmetrically arranged along the first central plane 211; the center plane of each radiation slot 25 is the fourth central plane 251; specifically, the fourth central plane 251 is perpendicular to the center of the top end face and the center of the bottom end face of the radiation slot, and the fourth central plane 251 is parallel to the long side of the radiation slot port. Each fourth central plane 251 is arranged parallel to the second central plane 221 or the third central plane 231.

[0059] Starting from the first center plane 211, the first radiating slot 25 on one side is located within the projection area of ​​the waveguide power divider cavity 22 and is offset towards the waveguide input cavity 21 along one side of the second center plane 221. The second and all subsequent radiating slots 25 are arranged within the projection area of ​​the waveguide extension cavity 23. Along both sides of the third center plane 231, the fourth center plane 251 of the second radiating slot 25 is offset away from the waveguide input cavity 21, and the fourth center plane 251 of the third radiating slot 25 is offset towards the waveguide input cavity 21, and so on. The offset of the relevant center planes of the above radiating slots 25 decreases successively. The lateral spacing of all radiating slots 25 is close to or the same, approximately half the waveguide wavelength.

[0060] In one specific implementation, refer to Figure 3 As shown, there are two radiation slots 25. At this time, the waveguide channel 2 only contains the waveguide input cavity 21 and the waveguide power splitter cavity 22; both radiation slots 25 are located in the projection area of ​​the waveguide power splitter cavity 22.

[0061] In one specific implementation, refer to Figures 5 to 7 As shown, the number of radiation slots 25 are four, six, and eight respectively; at this time, the waveguide channel 2 includes a waveguide input cavity 21, a waveguide power splitting cavity 22, and a waveguide extension cavity 23, wherein two radiation slots 25 are located in the projection area of ​​the waveguide power splitting cavity 22, and the remaining radiation slots are all located in the projection area of ​​the waveguide extension cavity.

[0062] On each side of the first center plane 211, adjust the offset between the third center plane 231 and the second center plane 221 so that the first radial slit 25 and the second radial slit 25 are arranged in a straight line or with a small offset.

[0063] Along the direction of signal transmission, the long side dimension of the cross-section of the waveguide power splitter cavity 22 (i.e., the H-plane width of the waveguide power splitter cavity 22) is close to or equal to the long side dimension of the cross-section of the waveguide extension cavity 23, and the short side dimension of the cross-section of the waveguide power splitter cavity 22 (i.e., the E-plane height of the waveguide power splitter cavity 22) is consistent with the short side dimension of the cross-section of the waveguide extension cavity. Both the long and short side dimensions meet the general requirements for the cutoff wavelength of the waveguide TE10 mode pair.

[0064] Along the direction of signal transmission, the long side dimension of the cross-section of the waveguide input cavity 21 (i.e., the H-plane width of the waveguide input cavity 21) is greater than the long side dimension of the cross-section of the waveguide power divider cavity 22, and the short side dimension of the cross-section of the waveguide input cavity 21 (i.e., the E-plane height of the waveguide input cavity 21) is the same as the short side dimension of the cross-section of the waveguide power divider cavity 22.

[0065] The length of the waveguide power division cavity 22 is about one waveguide wavelength; the length of the waveguide extension cavity 23 is about equal to 1 / 2 of the waveguide wavelength multiplied by the number of radiation slots 25 in the projection area. The width of the multimode coupling window 24 is less than the long side width of the waveguide power division cavity 22 and close to 1 / 2 of the operating wavelength. The spacing 242 is of an appropriate width to be suitable for different processing methods.

[0066] In a preferred embodiment, referring to Figure 8 and Figure 9 As shown, an artificial magnetic conductor can be used to replace the closed waveguide cavity, in addition to maintaining similar levels of antenna performance, some additional manufacturing cost optimization or manufacturing convenience can be obtained.

[0067] Specifically, in the practice of using an artificial magnetic conductor, the waveguide antenna comprises an antenna upper layer 26, an antenna lower layer 27, and a waveguide channel 2 formed by a certain number of magnetic conductor units 28. The waveguide channel 2 comprises a waveguide input cavity 21, a waveguide power division cavity 22, a waveguide extension cavity 23, and a radiation slot 25, and the structural features and size relationships are similar to the closed waveguide cavity structure scheme.

[0068] In a preferred embodiment, the magnetic conductor unit 28 can also be replaced by one or more enclosures, or a combination of enclosures and magnetic conductor units.

[0069] In a preferred embodiment, referring to the structure idea proposed by the present application, a 6-radiation slot waveguide antenna for a 77GHz frequency band of a car radar is designed and developed, which can realize a-10dB bandwidth of 11.6G, which is more than twice the target operating bandwidth (refer to Figure 10 As shown); and realizes a radiation performance of a side lobe level of more than-30dB (refer to Figure 11 As shown).

[0070] In a preferred embodiment, the multimode resonant waveguide slot antenna structure provided by the present application can be made of metal or surface metallized non-metal materials, and the processing technology can adopt manufacturing processes such as CNC numerical control processing, 3D printing, die casting, injection molding, etc. In processing, it can be integrally made, such as 3D printing, etc. It can also be appropriately divided into double-layer or multi-layer structures, respectively made and assembled and connected by means such as solder paste reflow soldering, ultrasonic welding, screwing, gluing, etc.

[0071] The utility model discloses a kind of waveguide radars, which uses the above multimode resonant waveguide slot antenna structure. The utility model discloses a kind of car, which uses the above waveguide radar.

[0072] In the description of the present application, it needs to be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0073] The specific embodiments of the present application are described above. It needs to be understood that the present application is not limited to the specific embodiments described above, and various changes or modifications can be made by those skilled in the art within the scope of the claims, which does not affect the essential content of the present application. In the case of no conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A multi-mode resonant waveguide slot antenna structure, characterized by, The application relates to a waveguide antenna (1) which comprises a waveguide channel (2). The waveguide channel (2) comprises a waveguide input cavity (21), a waveguide power division cavity (22), waveguide extension cavities (23) and a multimode coupling window (24). The waveguide input cavity (21) is connected with the waveguide power division cavity (22) perpendicularly; the waveguide extension cavities (23) are connected with the two ends of the waveguide power division cavity (22) respectively; the waveguide power division cavity (22) and the waveguide extension cavities (23) are communicated through the multimode coupling window (24); the opening of the multimode coupling window (24) is smaller than the width of the waveguide power division cavity (22) and the waveguide extension cavities (23). The top of the waveguide channel (2) is provided with a plurality of radiation slots (25). The opening width of the multimode coupling window (24) is 1 / 2 of the working wavelength.

2. The multi-mode resonant waveguide slot antenna structure of claim 1, wherein, The H-plane center plane of the waveguide input cavity (21) is a first center plane (211).

3. The multi-mode resonant waveguide slot antenna structure of claim 1, wherein, One end of the waveguide input cavity (21) is a waveguide feed port (212); the other end of the waveguide input cavity (21) is communicated with the waveguide power division cavity (22); and the waveguide power division cavity (22) is symmetrically arranged perpendicularly to the first center plane (211). The H-plane center plane of the waveguide power division cavity (22) is a second center plane (221); the H-plane center plane of the waveguide extension cavity (23) is a third center plane (231); the second center plane (221) is parallel to the third center plane (231) and is arranged in an offset manner; and the waveguide extension cavities (23) are vertically and symmetrically arranged about the second center plane (221).

4. The multi-mode resonant waveguide slot antenna structure of claim 3, wherein, The third center plane (231) is parallel to the second center plane (221) and is arranged in an offset manner along the direction of the waveguide input cavity (21).

5. The multi-mode resonant waveguide slot antenna structure of claim 4, wherein, Each waveguide extension cavity (23) forms a spacing (242) with the waveguide input cavity (21). The radiation slots (25) are arranged in an even number and are symmetrically distributed along the first center plane (211).

6. The multi-mode resonant waveguide slot antenna structure of claim 4, wherein, The first radiation slot (25) on one side of the first center plane (211) is located on the waveguide power division cavity (22); and the remaining radiation slots (25) are located on the waveguide extension cavities (23) and are arranged in an interlaced manner on both sides of the third center plane (231). The center plane of the radiation slot (25) is a fourth center plane (251); each fourth center plane (251) is arranged in parallel to the second center plane (221) or the third center plane (231).

7. The multi-mode resonant waveguide slot antenna structure of claim 6, wherein, The offset amount of the fourth center plane (251) about the parallel direction of the second center plane (221) or the third center plane (231) gradually decreases in the direction away from the first center plane (211). The waveguide channel (2) adopts a closed waveguide cavity.

8. The multi-mode resonant waveguide slot antenna structure of claim 1, wherein, Alternatively, the waveguide channel (2) is surrounded by an antenna upper layer (26), an antenna lower layer (27) and a magnetic conductor unit (28); the magnetic conductor unit (28) is located between the antenna upper layer (26) and the antenna lower layer (27) and is connected with the antenna upper layer (26) and the antenna lower layer (27) in contact or non-contact mode. ​ 9. A waveguide radar, characterized by A multi-mode resonant waveguide slot antenna structure comprising any one of claims 1 to 8.

10. An automobile characterized by comprising: A waveguide radar comprising the waveguide radar of claim 9.

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