Vehicle-mounted radar waveguide antenna structure

Abstract

The present invention relates to a vehicle-mounted radar waveguide antenna structure, wherein the antenna structure is a waveguide processing part, the waveguide processing part is formed by splicing an upper waveguide processing part (51) and a lower waveguide processing part (52) from top to bottom, and the upper waveguide processing part (51) and the lower waveguide processing part (52) are provided with a first waveguide transmission cavity (1), a waveguide antenna cavity structure, an electromagnetic bandgap structure (3) and an electromagnetic bandgap avoidance area (4) inside. Compared with a conventional terminal open-circuit waveguide antenna, the vehicle-mounted radar waveguide antenna structure of the present invention can realize the splicing of two layers of waveguide parts, and can horizontally stack a complex waveguide structure through reasonable design, so that the distribution characteristics of the two layers of waveguide parts can be simplified as much as possible, and the processing difficulty is greatly reduced, which is beneficial to commercial vehicle-mounted radars while improving performance and reducing costs, and can reduce the influence of waveguide processing errors on performance while maintaining a wide impedance bandwidth.

Description

Technical Field

[0001] The invention relates to the field of waveguide antennas, and in particular to a vehicle-mounted radar waveguide antenna structure. Background Art

[0002] With the rapid development of high-level intelligent driving in recent years, 4D millimeter-wave imaging radar is playing an increasingly important role with its multi-dimensional information perception capabilities and low cost advantages. People are constantly exploring and developing millimeter-wave radars with higher resolution and longer detection distances. In order to increase the detection distance and improve the resolution of millimeter-wave radars, it is necessary to increase the number of radar channels and improve the radiation performance of antennas in the array. The microstrip series-fed antenna solution currently commonly used in the industry has the problem of mutual coupling interference between the feed line and the antenna, and has significant deficiencies in antenna radiation performance, feed line loss, and array freedom. In order to improve feed loss and reduce the impact of feed lines on antennas, many existing technologies have proposed waveguide antennas instead of microstrip antennas, which have improved feed line loss, antenna radiation performance, and array freedom. However, due to the small size of conventional waveguide slot antennas in the 77GHz frequency band, the antenna performance is greatly affected by batch processing consistency. There are also many existing technologies that use terminal open-circuit waveguide antenna solutions. However, due to the complex structure of the multi-stage power divider, it is generally necessary to splice more than three waveguide parts. If the SMT welding solution is not used between the spliced ​​parts, the electromagnetic energy leakage will have a great impact on the antenna performance. Regardless of whether multiple waveguide parts are spliced ​​or the SMT welding solution is used, the processing cost will be greatly increased. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a vehicle-mounted radar waveguide antenna structure.

[0004] In order to achieve the above object, the vehicle-mounted radar waveguide antenna structure of the present invention is as follows:

[0005] The vehicle-mounted radar waveguide antenna structure has the following main features: the antenna structure is a waveguide processing part, which is formed by splicing an upper waveguide processing part and a lower waveguide processing part from top to bottom, and the upper waveguide processing part and the lower waveguide processing part are provided with a first waveguide transmission cavity, a waveguide antenna cavity structure, an electromagnetic band gap structure and an electromagnetic band gap avoidance zone.

[0006] Preferably, the first waveguide transmission cavity is a rectangular waveguide of WR12, and feeds electromagnetic energy along the waveguide guiding direction.

[0007] Preferably, the waveguide antenna cavity structure includes a variable polarization structure, and the variable polarization structure is used to feed electromagnetic energy from a first waveguide transmission cavity with a vertical long side to a second waveguide transmission cavity with a vertical short side.

[0008] Preferably, the variable polarization structure includes a first inward convex structure and a second inward convex structure, and the first inward convex structure and the second inward convex structure are used to feed electromagnetic energy from a first waveguide transmission cavity vertically arranged on a long side to a second waveguide transmission cavity vertically arranged on a short side to achieve low-loss transmission.

[0009] Preferably, the second waveguide transmission cavity is arranged in the upper waveguide processing piece, and the cavity guiding direction of the second waveguide transmission cavity and the cavity guiding direction of the first waveguide transmission cavity are both in a plane parallel to the antenna radiation surface, and the directions differ by 90°.

[0010] Preferably, the waveguide antenna cavity structure also includes a third waveguide transmission cavity arranged in the upper waveguide processing part and the lower waveguide processing part, and the third waveguide transmission cavity is composed of a symmetrically distributed first transmission cavity and a second transmission cavity, and the first transmission cavity and the second transmission cavity are both arranged with long sides vertically and short sides horizontally.

[0011] Preferably, the waveguide antenna cavity structure further comprises a first waveguide power division structure, and the first waveguide power division structure is used to distribute electromagnetic energy from the second waveguide transmission cavity with a short side vertically arranged to the first transmission cavity and the second transmission cavity with two long sides vertically arranged with equal power;

[0012] The cavity guiding direction of the first transmission cavity and the cavity guiding direction of the second transmission cavity are both in the parallel plane of the antenna radiation surface, with a direction difference of 90°, and the cavity guiding directions of the first transmission cavity and the second transmission cavity are respectively 180° different.

[0013] Preferably, the first waveguide power division structure includes a third inward convex structure and a fourth inward convex structure, and the fourth inward convex structure passes through the bottom of the first transmission cavity and the second transmission cavity.

[0014] Preferably, it further comprises a fourth waveguide transmission cavity disposed in the lower waveguide processing piece with its long side arranged horizontally and its short side arranged vertically, wherein the fourth waveguide transmission cavity comprises two completely symmetrical first waveguide sub-transmission cavities and second waveguide sub-transmission cavities, and the first waveguide sub-transmission cavity and the second waveguide sub-transmission cavity are respectively connected to the ends of the first transmission cavity and the second transmission cavity;

[0015] The cavity guiding direction of the fourth waveguide transmission cavity and the cavity guiding direction of the third waveguide transmission cavity are both in a plane parallel to the antenna radiation surface, with a direction difference of 90°, and are located at the lower part of the third waveguide transmission cavity.

[0016] Preferably, the waveguide antenna cavity structure also includes a second waveguide power division structure, which is used to distribute electromagnetic energy from the first waveguide sub-transmission cavity and the second waveguide sub-transmission cavity with vertical short sides to the radiation structure, and the second waveguide power division structure is connected to the radiation structure through a waveguide.

[0017] Preferably, the second waveguide power division structure comprises two first waveguide power molecular structures and a second waveguide power molecular structure of the same size and symmetrically distributed; the radiation structure comprises a first radiation element, a second radiation element, a third radiation element and a fourth radiation element; the second waveguide power division structure is used to distribute electromagnetic energy from the first waveguide sub-transmission cavity and the second waveguide sub-transmission cavity with vertical short sides to the first radiation element, the second radiation element, the third radiation element and the fourth radiation element with equal power;

[0018] Furthermore, the cavity guiding direction of the connection part between the second waveguide power division structure and the first radiation element, the second radiation element, the third radiation element and the fourth radiation element is 90° different from the cavity guiding direction of the fourth waveguide transmission cavity.

[0019] Preferably, the waveguide power division structure is provided with an inward convex structure on both sides of the bottom connected to the first waveguide sub-transmission cavity and the second waveguide sub-transmission cavity, and by adjusting the size of the inward convex structure, low-loss transmission of electromagnetic energy from the fourth waveguide transmission cavity with two short sides arranged vertically to the four first radiation element, the second radiation element, the third radiation element and the fourth radiation element is achieved.

[0020] Preferably, the electromagnetic band gap structure includes a first metal column structure, a metal strip structure and a second metal column structure. The first metal column structure, the metal strip structure and the second metal column structure are used in combination to cooperate with the electromagnetic band gap avoidance zone to suppress the electromagnetic energy leakage of the waveguide power division structure, the third waveguide transmission cavity and the fourth waveguide transmission cavity.

[0021] Compared with conventional terminal open-circuit waveguide antennas, the vehicle-mounted radar waveguide antenna structure of the present invention can realize the splicing of two layers of waveguide parts, and the complex waveguide structure can be horizontally stacked through reasonable design to realize the splicing of two layers of waveguide parts. At the same time, its simplified distribution characteristics greatly reduce the difficulty of processing, and the reduction in the number of waveguide parts leads to a reduction in processing costs, which is conducive to commercial vehicle-mounted radars while improving performance and reducing costs. On this basis, due to the large feature size design, the processing is convenient, and the influence of waveguide processing errors on performance can be reduced while maintaining a wide impedance bandwidth, especially the offset of impedance bandwidth. In addition, if plastic parts are metallized, the simpler features are not easy to cause the problem of inconsistent metal plating at small feature positions. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a three-dimensional view of the vehicle-mounted radar waveguide antenna structure of the present invention.

[0023] Figure 2 It is a side view of the vehicle-mounted radar waveguide antenna structure of the present invention.

[0024] Figure 3 This is a three-dimensional view of the upper waveguide component of the vehicle-mounted radar waveguide antenna structure of the present invention after processing.

[0025] Figure 4 This is a three-dimensional view of the lower waveguide component of the vehicle-mounted radar waveguide antenna structure of the present invention after processing.

[0026] Figure 5 This is a three-dimensional view of the complete waveguide component of the vehicle-mounted radar waveguide antenna structure of the present invention after processing.

[0027] Figure 6 It is a three-dimensional view of the variable polarization structure inside the vehicle-mounted radar waveguide antenna structure of the present invention.

[0028] Figure 7 This is a three-dimensional view of the first part of the waveguide power distribution structure inside the vehicle-mounted radar waveguide antenna structure of the present invention.

[0029] Figure 8 This is a three-dimensional view of the second part of the waveguide power division structure and the radiation element inside the vehicle-mounted radar waveguide antenna structure of the present invention.

[0030] Fig. 9 It is a top view of the electromagnetic band gap structure and avoidance area inside the vehicle-mounted radar waveguide antenna structure of the present invention.

[0031] Fig.10 It is a flow chart of a vehicle-mounted radar waveguide antenna structure in a specific implementation manner of the present invention.

[0032] Fig.11 The E-plane and H-plane radiation patterns of the vehicle-mounted radar waveguide antenna structure of the present invention when the gaps between the waveguide components are 0 mm and 0.1 mm.

[0033] Fig.12 A three-dimensional view of a vehicle-mounted radar antenna array in an embodiment of the present invention.

[0034] Fig.13 1 and 2 are the E-plane and H-plane radiation patterns of the antenna unit in the vehicle-mounted radar antenna array in the embodiment of the present invention.

[0035] Reference numerals

[0036] 1. The first waveguide transmission cavity

[0037] 21 Variable polarization structure

[0038] 22 Second waveguide transmission cavity

[0039] 211 First convex structure

[0040] 212 Second convex structure

[0041] 23 First waveguide power division structure

[0042] 231 The third convex structure

[0043] 232 Fourth convex structure

[0044] 24 The third waveguide transmission cavity

[0045] 241 First transmission cavity

[0046] 242 Second transmission cavity

[0047] 25 Fourth waveguide transmission cavity

[0048] 251 The First Waveguide Transmission Cavity

[0049] 252 Second waveguide transmission cavity

[0050] 26 Second waveguide power division structure

[0051] 261 The first waveguide molecular structure

[0052] 262 The second waveguide molecular structure

[0053] 27 Radiating Structure

[0054] 271 First Radiating Element

[0055] 272 Second radiating element

[0056] 273 Third radiating element

[0057] 274 Fourth Radiating Element

[0058] 3 Electromagnetic band gap structure

[0059] 31 First metal column structure

[0060] 32 Metal Strip Structure

[0061] 33 Second metal column structure

[0062] 4 Electromagnetic band gap avoidance zone

[0063] 51 Upper waveguide processing parts

[0064] 52 Lower waveguide processing parts DETAILED DESCRIPTION

[0065] In order to more clearly describe the technical content of the present invention, further description is given below in conjunction with specific embodiments.

[0066] Before describing in detail embodiments according to the present invention, it should be noted that, hereinafter, the terms "comprises", "includes" or any other variations are intended to cover non-exclusive inclusion, whereby a process, method, article or apparatus comprising a series of elements includes not only these elements, but also other elements not explicitly listed or inherent to such process, method, article or apparatus.

[0067] See also Figures 1 to 5 As shown, the vehicle-mounted radar waveguide antenna structure, wherein the antenna structure is a waveguide processing part, the waveguide processing part 5 is formed by splicing an upper waveguide processing part 51 and a lower waveguide processing part 52 from top to bottom, and the upper waveguide processing part 51 and the lower waveguide processing part 52 are internally provided with a first waveguide transmission cavity 1, a waveguide antenna cavity structure, an electromagnetic band gap structure 3 and an electromagnetic band gap avoidance area 4.

[0068] As a preferred embodiment of the present invention, the first waveguide transmission cavity 1 is a rectangular waveguide of WR12, and electromagnetic energy is fed along the waveguide guiding direction.

[0069] As a preferred embodiment of the present invention, the waveguide antenna cavity structure includes a variable polarization structure 21, and the variable polarization structure 21 is used to feed electromagnetic energy from the first waveguide transmission cavity 1 with a vertical long side to the second waveguide transmission cavity 22 with a vertical short side.

[0070] like Figure 6 As shown, as a preferred embodiment of the present invention, the variable polarization structure 21 includes a first inward convex structure 211 and a second inward convex structure 212. The first inward convex structure 211 and the second inward convex structure 212 are used to feed electromagnetic energy from the first waveguide transmission cavity 1 with a vertical long side to the second waveguide transmission cavity 22 with a vertical short side to achieve low-loss transmission.

[0071] As a preferred embodiment of the present invention, the second waveguide transmission cavity 22 is arranged in the upper waveguide processing part 51, and the cavity guiding direction of the second waveguide transmission cavity 22 and the cavity guiding direction of the first waveguide transmission cavity 1 are both in a plane parallel to the antenna radiation surface, and the directions differ by 90°.

[0072] As a preferred embodiment of the present invention, the waveguide antenna cavity structure also includes a third waveguide transmission cavity 24 arranged in the upper waveguide processing part 51 and the lower waveguide processing part 52, and the third waveguide transmission cavity 24 is composed of a symmetrically distributed first transmission cavity 241 and a second transmission cavity 242, and the first transmission cavity 241 and the second transmission cavity 242 are both arranged with long sides vertically and short sides horizontally.

[0073] As a preferred embodiment of the present invention, the waveguide antenna cavity structure further includes a first waveguide power division structure 23, and the first waveguide power division structure 23 is used to distribute electromagnetic energy from the second waveguide transmission cavity 22 with a short side vertically to the first transmission cavity 241 and the second transmission cavity 242 with two long sides vertically;

[0074] The cavity guiding directions of the first transmission cavity 241 and the second transmission cavity 242 are in parallel with the cavity guiding direction of the second waveguide transmission cavity 22 on the plane parallel to the antenna radiation surface, with a direction difference of 90°, and the cavity guiding directions of the first transmission cavity 241 and the second transmission cavity 242 are 180° different from each other.

[0075] like Figure 7 As shown, as a preferred embodiment of the present invention, the first waveguide power division structure 23 includes a third inward convex structure 231 and a fourth inward convex structure 232, and the fourth inward convex structure 232 passes through the bottom of the first transmission cavity 241 and the second transmission cavity 242.

[0076] like Figure 8 As shown, as a preferred embodiment of the present invention, the fourth waveguide transmission cavity 25 is arranged in the lower waveguide processing piece 52 with its long side placed horizontally and its short side placed vertically, and includes two completely symmetrical first waveguide sub-transmission cavities 251 and second waveguide sub-transmission cavities 252, and the first waveguide sub-transmission cavities 251 and the second waveguide sub-transmission cavities 252 are respectively connected to the ends of the first transmission cavity 241 and the second transmission cavity 242;

[0077] Moreover, the cavity guiding direction of the fourth waveguide transmission cavity 25 and the cavity guiding direction of the third waveguide transmission cavity 24 are both in the parallel plane of the antenna radiation surface, with a direction difference of 90°, and are located at the lower part of the third waveguide transmission cavity 24 .

[0078] As a preferred embodiment of the present invention, the waveguide antenna cavity structure 2 also includes a second waveguide power division structure 26, which is used to distribute electromagnetic energy from the first waveguide sub-transmission cavity 251 and the second waveguide sub-transmission cavity 252 with vertical short sides to the radiation structure 27, and the second waveguide power division structure 26 is connected to the radiation structure 27 through a waveguide.

[0079] As a preferred embodiment of the present invention, the second waveguide power division structure 26 includes two first waveguide power molecular structures 261 and second waveguide power molecular structures 262 of the same size and symmetrically distributed; the radiation structure 27 includes a first radiation element 271, a second radiation element 272, a third radiation element 273 and a fourth radiation element 274; the second waveguide power division structure 26 is used to distribute electromagnetic energy from the first waveguide sub-transmission cavity 251 and the second waveguide sub-transmission cavity 252 with vertical short sides to the first radiation element 271, the second radiation element 272, the third radiation element 273 and the fourth radiation element 274 with equal power;

[0080] Furthermore, the cavity guiding direction of the connection part between the second waveguide power division structure 26 and the first radiation element 271 , the second radiation element 272 , the third radiation element 273 and the fourth radiation element 274 is 90° different from the cavity guiding direction of the fourth waveguide transmission cavity 25 .

[0081] As a preferred embodiment of the present invention, the second waveguide power division structure 26 is provided with an inward convex structure on both sides of the bottom connected to the first waveguide sub-transmission cavity 251 and the second waveguide sub-transmission cavity 252. By adjusting the size of the inward convex structure, low-loss transmission of electromagnetic energy is achieved from the fourth waveguide transmission cavity 25 with two short sides arranged vertically to the four first radiation elements 271, the second radiation element 272, the third radiation element 273 and the fourth radiation element 274.

[0082] like Fig. 9 As shown, as a preferred embodiment of the present invention, the electromagnetic band gap structure 3 includes a first metal column structure 31, a metal strip structure 32 and a second metal column structure 33. The first metal column structure 31, the metal strip structure 32 and the second metal column structure 33 are used in combination to cooperate with the electromagnetic band gap avoidance zone 4 to suppress the electromagnetic energy leakage of the waveguide power division structure 23, the third waveguide transmission cavity 24 and the fourth waveguide transmission cavity 25.

[0083] The vehicle-mounted radar waveguide antenna structure of the present technical solution will be further described in detail below. Fig.12 As shown, this embodiment is a partial display of a vehicle-mounted radar waveguide antenna array. The antenna part of this embodiment is designed based on the present technical solution. There are 4 channels in total, and 4 antenna units are connected through waveguide transmission feeders. Each channel consists of four parts, which are respectively composed of a first waveguide transmission cavity 1, a waveguide antenna cavity structure, an electromagnetic bandgap structure 3, an electromagnetic bandgap avoidance area 4, and a waveguide processing part that can actually be processed and contains the above-mentioned features.

[0084] The first waveguide transmission cavity 1 is a rectangular waveguide with a standard size of WR12, and electromagnetic energy is fed along the waveguide guiding direction. The waveguide guiding direction is parallel to the antenna radiation surface. The long side of the rectangular waveguide is placed vertically, and the long side size is twice the short side size. In actual design, the size of the first waveguide transmission cavity 1 can be any rectangular waveguide size with a cutoff frequency higher than the operating frequency. In actual processing of waveguide parts, the inside of the rectangular waveguide is hollowed out, and the inner wall surface is a metal material with high electrical conductivity. The actual processed waveguide processing parts can be metal parts, or they can be other non-metallic materials that can be injection molded or CNCed and the surface is metallized. All waveguide antenna features including the first waveguide transmission cavity 1 are realized on the waveguide processing parts by injection molding or CNC, which are divided into upper waveguide processing parts 51 and lower waveguide processing parts 52, such as Figure 3 and Figure 4 In order to realize the splicing of two layers of waveguides, the waveguides are divided into two parts from the middle line of the vertical long side of the waveguide transmission cavity. Since the field lines of the main mode are distributed in the middle line of the vertical long side of the waveguide transmission cavity, even if there is a gap, the leakage of electromagnetic energy will be greatly suppressed.

[0085] The waveguide antenna cavity structure is divided into a variable polarization structure 21 , a second waveguide transmission cavity 22 , a waveguide power division structure 23 , a third waveguide transmission cavity 24 , a fourth waveguide transmission cavity 25 , a waveguide power division structure 26 and a radiation structure 27 .

[0086] The variable polarization structure 21 realizes the feeding of electromagnetic energy from the first waveguide transmission cavity 1 with a long side vertically arranged to the second waveguide transmission cavity 22 with a short side vertically arranged. The cavity guiding direction of the second waveguide transmission cavity 22 and the cavity guiding direction of the first waveguide transmission cavity 1 are both in a plane parallel to the antenna radiation surface, but the directions differ by 90°. The second waveguide transmission cavity 22 has the same waveguide size as the first waveguide transmission cavity 1, with the horizontal arrangement being the long side of the waveguide and the vertical arrangement being the short side of the waveguide, since the long side is twice the length of the short side. The variable polarization structure 21 includes a first inward convex structure 211 and a second inward convex structure 212. By optimizing the dimensions of the two inward convex structures, low-loss transmission of electromagnetic energy from the first waveguide transmission cavity 1 with a long side vertically arranged to the second waveguide transmission cavity 22 with a short side vertically arranged can be realized.

[0087] The second waveguide transmission cavity 22 has the same waveguide size as the first waveguide transmission cavity 1, but the short side is placed vertically, so the second waveguide transmission cavity 22 is located in the upper half of the first waveguide transmission cavity 1. Due to the processability of the waveguide component, the first waveguide transmission cavity 1 needs to be split into two parts, located in the upper waveguide processing component 51 and the lower waveguide processing component 52. The second waveguide transmission cavity 22 is completely in the upper waveguide processing component 51, so that the characteristics of the two layers of waveguide components are simplified. The special electromagnetic bandgap structure is matched between the variable polarization structure 21 and the second waveguide transmission cavity 22, which can maximize the limit and suppression of electromagnetic energy leakage caused by the gap. The length of the second waveguide transmission cavity 22 is very short, which can help the final waveguide antenna to have a horizontal size as small as possible.

[0088] The function of the waveguide power division structure 23 is to distribute the electromagnetic energy from the second waveguide transmission cavity 22 with a short side vertically to the first transmission cavity 241 and the second transmission cavity 242 with two long sides vertically. The cavity guiding direction of the first transmission cavity 241 and the second transmission cavity 242 is parallel to the antenna radiation surface, but the direction differs by 90°. The cavity guiding directions of the first transmission cavity 241 and the second transmission cavity 242 differ by 180°. The waveguide power division structure 23 mainly includes a third inward convex structure 231 and a fourth inward convex structure 232. The fourth inward convex structure 232 runs through the bottom of the first transmission cabin 241 and the second transmission cabin 242. The waveguide power division structure 23 not only completes the equal power distribution of electromagnetic energy, but is also a similar HT-type power division structure. In addition, it also realizes the effect of polarization change. By optimizing the dimensions of the third inward convex structure 231 and the fourth inward convex structure 232 , low-loss transmission of electromagnetic energy from the second waveguide transmission cavity 22 with a short side vertically arranged to the third waveguide transmission cavity 24 with two long sides vertically arranged can be achieved.

[0089] The third waveguide transmission cavity 24 includes two completely identical and symmetrically distributed first transmission cavities 241 and second transmission cavities 242, both of which are vertically arranged on the long side and horizontally arranged on the short side. The advantage of this design is to reduce the horizontal size of the waveguide antenna. In the actual processing of the third waveguide transmission cavity 24, the interior of the rectangular waveguide is hollowed out, and the inner wall surface is a metal material with high electrical conductivity. In order to achieve layer splicing, the waveguide processing part is divided into two parts of waveguide parts from the middle of the long side of the waveguide transmission cavity, which are divided into an upper waveguide processing part 51 and a lower waveguide processing part 52. Since the waveguide transmission cavity has a vertical short side, it is not suitable for a conventional electromagnetic bandgap structure, and a new form of electromagnetic bandgap structure needs to be customized.

[0090] The fourth waveguide transmission cavity 25 includes two completely symmetrical first waveguide sub-transmission cavities 251 and second waveguide sub-transmission cavities 252, which are connected to the ends of the first transmission cavity 241 and the second transmission cavity 242 respectively. The cavity guiding direction of the fourth waveguide transmission cavity 25 and the cavity guiding direction of the third waveguide transmission cavity 24 are both in the parallel plane with the antenna radiation surface, but the directions differ by 90°. The fourth waveguide transmission cavity 25 still has the same waveguide size as the first waveguide transmission cavity 1, with the short side vertically and the long side horizontally, so the fourth waveguide transmission cavity 25 is just located in the lower half of the third waveguide transmission cavity 24. Due to the processability of the waveguide component, the third waveguide transmission cavity 24 needs to be split into two parts from top to bottom, which are set in the upper waveguide processing component 51 and the lower waveguide processing component 52. The fourth waveguide transmission cavity 25 is completely in the lower waveguide processing component 52. The length of the fourth waveguide transmission cavity 25 is very short, which can help the final waveguide antenna to have the smallest horizontal size possible. The connecting portion between the fourth waveguide transmission cavity 25 and the third waveguide transmission cavity 24 actually completes the polarization change function, and this portion does not have an additional inner convex structure and still achieves low-loss transmission of electromagnetic energy.

[0091] The second waveguide power division structure 26 comprises two first waveguide power molecular structures 261 and a second waveguide power molecular structure 262 of exactly the same size and symmetrically distributed. The function of the second waveguide power division structure 26 is to distribute electromagnetic energy from the two first waveguide sub-transmission cavities 251 and the second waveguide sub-transmission cavities 252 with vertical short sides to four first radiation elements 271, second radiation element 272, third radiation element 273 and fourth radiation element 274 with approximately equal power. The cavity guiding direction of the connecting part of the second waveguide power division structure 26 with the first waveguide sub-transmission cavity 251 and the second waveguide sub-transmission cavity 252 is the normal direction perpendicular to the radiation surface of the waveguide antenna. The cavity guiding direction of the connecting part of the second waveguide power division structure 26 with the four radiation elements is 90° different from the cavity guiding direction of the fourth waveguide transmission cavity 25. The first waveguide power molecular structure 261 and the second waveguide power molecular structure 262 are similar to the HT type waveguide power division structure, and there is an inner convex structure on both sides of the bottom connected to the first waveguide sub-transmission cavity 251 and the second waveguide sub-transmission cavity 252. By optimizing the size of the two inner convex structures, low-loss transmission of electromagnetic energy from the fourth waveguide transmission cavity 25 with two short sides vertically arranged to the four-way radiation element can be achieved. The cavity center spacing of the connection part of the second waveguide power division structure 26 and the four-way radiation element is designed according to the unit spacing of the radiation element. The input waveguide port of the first waveguide power molecular structure 261 and the second waveguide power molecular structure 262 is located in the middle of the two output waveguide ports, and the input main path and the two output branch cavity guiding directions are both normal directions perpendicular to the radiation surface of the waveguide antenna. The branch close to the middle of the waveguide antenna is slightly higher than the branch close to the edge of the waveguide antenna. This is for the design of low side lobes in the elevation direction of the waveguide antenna. By optimizing the dimensions of the two inner convex structures, not only can low-loss transmission of electromagnetic energy from the two short-side vertical fourth waveguide transmission cavities 25 to the four-way radiation elements be achieved, but also the distribution power of the branches can be adjusted.

[0092] The radiation structure 27 includes four radiation elements. The connection part between the radiation structure 27 and the second waveguide power division structure 26 is a waveguide with the same waveguide size as the first waveguide transmission cavity 1. The end of the radiation element is a horn-shaped structure. The horizontal aperture of the end radiation surface is larger than the waveguide size of the first waveguide transmission cavity 1. The horizontal size is related to the horizontal dimension radiation pattern beam width of the waveguide antenna. If a smaller beam width and a larger normal gain are required, it is necessary to increase the horizontal aperture of the end radiation surface. The elevation aperture of the end radiation surface is the same as the waveguide size of the first waveguide transmission cavity 1. The elevation aperture of the end radiation surface cannot be smaller than the elevation size of the transmission waveguide in design. This is to take into account the machinability of the upper waveguide processing part 51 by injection molding or mechanical CNC, and at the same time ensure that the cavity wall thickness between adjacent radiation surfaces is not too thin to meet the processing requirements. The four radiation elements are exactly the same size, with the center pointing in a direction parallel to the elevation surface.

[0093] The electromagnetic bandgap structure 3 includes metal column structures 31 and 33, and a metal strip structure 32. Because the waveguide antenna needs to realize two-layer splicing and meet the conventional screw installation. Therefore, it is necessary to suppress the electromagnetic energy leakage caused by the gap through the electromagnetic bandgap structure, but the waveguide antenna flattens the structure for two-layer splicing, completes the three polarization transformations of the main mode of the electromagnetic wave, and the conventional periodic arrangement of metal columns is not suitable for the complex internal structure, so different structures need to be used for different components. The column size, column height and column spacing of the first metal column structure 31 and the second metal column structure 33 will affect the frequency range of suppressing electromagnetic energy leakage. The electromagnetic bandgap avoidance area 4 is an area actually hollowed out in the waveguide part, and the height is the same as the electromagnetic bandgap structure 3, and the distance from the metal column structure is not less than the metal column spacing. The first metal column structure 31 cooperates with the electromagnetic bandgap avoidance area 4 to suppress the electromagnetic energy leakage of the variable polarization structure 21 and the second waveguide transmission cavity 22 when there is a gap in the connection between the upper waveguide processing part 51 and the lower waveguide processing part 52. The first metal column structure 31 and the metal strip structure 32 cooperate with the electromagnetic band gap avoidance zone 4 to suppress the electromagnetic energy leakage of the waveguide power division structure 23, the third waveguide transmission cavity 24 and the fourth waveguide transmission cavity 25 when there is a gap between the upper waveguide processing part 51 and the lower waveguide processing part 52.

[0094] Through the cooperation of the metal strip structure 32 and the second metal column structure 33 with the electromagnetic band gap avoidance zone 4, on the basis of the horizontally stacked terminal open-circuit waveguide antenna with multiple polarization transformations, the two layers of waveguide parts are spliced ​​and meet the requirements of conventional screw installation. The high radiation efficiency of the waveguide antenna is still exerted by suppressing the leakage of electromagnetic energy.

[0095] The electromagnetic energy is fed to the first waveguide transmission cavity 1 of each channel through the radio frequency chip, and then fed to each waveguide antenna unit. Fig.13 The horizontal and elevation axial radiation patterns of the four waveguide antennas in the array are shown. It can be seen that the radiation and inter-channel consistency of each waveguide antenna in the array are good.

[0096] In practical application, this technical solution has the following technical advantages:

[0097] 1. Compared with the conventionally designed terminal open-circuit waveguide antenna, the vehicle-borne guided radar antenna described in this technical solution can realize the splicing of two layers of waveguide parts, and the complex waveguide structure can be horizontally stacked through reasonable design. While realizing the splicing of two layers of waveguide parts, the distribution characteristics are simplified as much as possible, and the processing difficulty is greatly reduced. The reduction in the number of waveguide parts means the reduction of processing costs, which is conducive to the commercial vehicle-borne radar while improving performance and reducing costs. 2. Compared with the conventionally designed waveguide slot antenna, the design similar to the terminal open-circuit waveguide antenna described in the present invention has a larger feature size and is easy to process. While maintaining a very wide impedance bandwidth, it can reduce the impact of waveguide processing errors on performance, especially the offset of impedance bandwidth. In addition, if plastic parts are metallized, the simpler features are not easy to cause the problem of inconsistent metal plating at small feature positions. 3. Compared with the conventionally designed waveguide antenna, the vehicle-borne guided radar antenna described in the present invention does not require special welding methods when the number of waveguide parts is small enough, the features are simple and the size is large. It does not need to use SMT or laser ultrasonic welding. Even in the case of screw installation, it can still suppress the leakage of electromagnetic energy caused by the installation gap and the degradation of antenna pattern performance.

[0098] The waveguide antenna is made of two waveguide parts. The two waveguide parts do not need to be completely sealed by welding. Even if there is a gap at the connection, the effect on the waveguide antenna is very small. Fig.11 Shown are the horizontal and elevation axial radiation patterns of the waveguide antenna when the gap at the joint is 0mm and 0.1mm. It can be seen that there is little difference in the normal gain or the radiation pattern beam width.

[0099] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present invention belong.

[0100] In the description of this specification, the description with reference to the terms "an embodiment", "some embodiments", "example", "specific example", or "embodiment" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0101] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

[0102] Compared with conventional terminal open-circuit waveguide antennas, the vehicle-mounted radar waveguide antenna structure of the present invention can realize the splicing of two layers of waveguide parts, and the complex waveguide structure can be horizontally stacked through reasonable design to realize the splicing of two layers of waveguide parts. At the same time, its simplified distribution characteristics greatly reduce the difficulty of processing, and the reduction in the number of waveguide parts leads to a reduction in processing costs, which is conducive to commercial vehicle-mounted radars while improving performance and reducing costs. On this basis, due to the large feature size design, the processing is convenient, and the influence of waveguide processing errors on performance can be reduced while maintaining a wide impedance bandwidth, especially the offset of impedance bandwidth. In addition, if plastic parts are metallized, the simpler features are not easy to cause the problem of inconsistent metal plating at small feature positions.

[0103] In this specification, the present invention has been described with reference to specific embodiments thereof. However, it is apparent that various modifications and variations may be made without departing from the spirit and scope of the present invention. Therefore, the specification and drawings should be regarded as illustrative rather than restrictive.

Claims

1. A vehicle-mounted radar waveguide antenna structure, characterized in that: The antenna structure is a waveguide processing part, the waveguide processing part is formed by splicing an upper waveguide processing part (51) and a lower waveguide processing part (52) from top to bottom, and the upper waveguide processing part (51) and the lower waveguide processing part (52) are provided with a first waveguide transmission cavity (1), a waveguide antenna cavity structure (2), an electromagnetic band gap structure (3) and an electromagnetic band gap avoidance area (4) inside, the waveguide antenna cavity structure (2) also includes a first waveguide power division structure (23) and a third waveguide transmission cavity (24) arranged in the upper waveguide processing part (51) and the lower waveguide processing part (52), and a fourth waveguide transmission cavity (25) arranged in the lower waveguide processing part (52) with its long side arranged horizontally and its short side arranged vertically; The waveguide antenna cavity structure (2) further comprises a variable polarization structure (21), wherein the variable polarization structure (21) is used to feed electromagnetic energy from a first waveguide transmission cavity (1) with a vertical long side to a second waveguide transmission cavity (22) with a vertical short side. The polarization-changing structure (21) comprises a first inwardly convex structure (211) and a second inwardly convex structure (212), wherein the first inwardly convex structure (211) and the second inwardly convex structure (212) are used to feed electromagnetic energy from a first waveguide transmission cavity (1) with a vertical long side to a second waveguide transmission cavity (22) with a vertical short side, thereby achieving low-loss transmission; The electromagnetic bandgap structure (3) comprises a first metal column structure (31), a metal strip structure (32) and a second metal column structure (33). The first metal column structure (31), the metal strip structure (32) and the second metal column structure (33) are used in combination to cooperate with the electromagnetic bandgap avoidance zone (4) to suppress electromagnetic energy leakage in the first waveguide power division structure (23), the third waveguide transmission cavity (24) and the fourth waveguide transmission cavity (25).

2. The vehicle-mounted radar waveguide antenna structure according to claim 1, characterized in that: The first waveguide transmission cavity (1) is a rectangular waveguide of WR12, and feeds electromagnetic energy along the waveguide guiding direction.

3. The vehicle-mounted radar waveguide antenna structure according to claim 1, characterized in that: The second waveguide transmission cavity (22) is arranged in the upper waveguide processing piece (51), and the cavity guiding direction of the second waveguide transmission cavity (22) and the cavity guiding direction of the first waveguide transmission cavity (1) are both on a plane parallel to the antenna radiation surface, and the directions differ by 90°.

4. The vehicle-mounted radar waveguide antenna structure according to claim 1, characterized in that: The third waveguide transmission cavity (24) is composed of a first transmission cavity (241) and a second transmission cavity (242) that are symmetrically distributed, and the first transmission cavity (241) and the second transmission cavity (242) are both arranged with their long sides arranged vertically and their short sides arranged horizontally.

5. The vehicle-mounted radar waveguide antenna structure according to claim 4, characterized in that: The first waveguide power division structure (23) is used to distribute electromagnetic energy from the second waveguide transmission cavity (22) with a short side arranged vertically to two first transmission cavities (241) and second transmission cavities (242) with long sides arranged vertically with equal power; The cavity guiding directions of the first transmission cavity (241) and the second transmission cavity (242) and the cavity guiding direction of the second waveguide transmission cavity (22) are both on a plane parallel to the antenna radiation surface, with a direction difference of 90°, and the cavity guiding directions of the first transmission cavity (241) and the second transmission cavity (242) are respectively 180° different.

6. The vehicle-mounted radar waveguide antenna structure according to claim 5, characterized in that: The first waveguide power division structure (23) comprises a third inward convex structure (231) and a fourth inward convex structure (232), and the fourth inward convex structure (232) runs through the bottom of the first transmission cavity (241) and the second transmission cavity (242).

7. The vehicle-mounted radar waveguide antenna structure according to claim 5, characterized in that: The fourth waveguide transmission cavity (25) comprises two completely symmetrical first waveguide sub-transmission cavities (251) and second waveguide sub-transmission cavities (252), wherein the first waveguide sub-transmission cavity (251) and the second waveguide sub-transmission cavity (252) are respectively connected to the ends of the first transmission cavity (241) and the second transmission cavity (242); Furthermore, the cavity guiding direction of the fourth waveguide transmission cavity (25) and the cavity guiding direction of the third waveguide transmission cavity (24) are both on a plane parallel to the antenna radiation surface, with a direction difference of 90°, and are located at the bottom of the third waveguide transmission cavity (24).

8. The vehicle-mounted radar waveguide antenna structure according to claim 5, characterized in that: The waveguide antenna cavity structure (2) further comprises a second waveguide power division structure (26), wherein the second waveguide power division structure (26) is used to distribute electromagnetic energy from the first waveguide sub-transmission cavity (251) and the second waveguide sub-transmission cavity (252) whose short sides are vertically arranged to the radiation structure (27), and the second waveguide power division structure (26) is connected to the radiation structure (27) via a waveguide.

9. The vehicle-mounted radar waveguide antenna structure according to claim 8, characterized in that: The second waveguide power division structure (26) comprises a first waveguide power molecular structure (261) and a second waveguide power molecular structure (262) of the same size and symmetrically distributed; the radiation structure (27) comprises a first radiation element (271), a second radiation element (272), a third radiation element (273) and a fourth radiation element (274); the second waveguide power division structure (26) is used to distribute electromagnetic energy from the first waveguide sub-transmission cavity (251) and the second waveguide sub-transmission cavity (252) with vertical short sides to the first radiation element (271), the second radiation element (272), the third radiation element (273) and the fourth radiation element (274) with equal power; Furthermore, the cavity guiding direction of the connection portion between the second waveguide power division structure (26) and the first radiation element (271), the second radiation element (272), the third radiation element (273) and the fourth radiation element (274) differs by 90° from the cavity guiding direction of the fourth waveguide transmission cavity (25).

10. The vehicle-mounted radar waveguide antenna structure according to claim 9, characterized in that: The second waveguide power division structure (26) is provided with an inner convex structure on both sides of the bottom connected to the first waveguide sub-transmission cavity (251) and the second waveguide sub-transmission cavity (252). By adjusting the size of the inner convex structure, low-loss transmission of electromagnetic energy is achieved from the fourth waveguide transmission cavity (25) with two short sides arranged vertically to the first radiation element (271), the second radiation element (272), the third radiation element (273) and the fourth radiation element (274).

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