Millimeter wave waveguide antenna

Abstract

The invention discloses a millimeter wave waveguide antenna, which comprises a first metal layer; the second metal layer is arranged on one side of the first metal layer and attached to the first metal layer, and the antenna is characterized in that a waveguide transmission groove and beam width limiting grooves formed in the two sides of the waveguide transmission groove are formed in the side, facing the first metal layer, of the second metal layer; a plurality of radiation slots are formed in the positions, corresponding to the waveguide transmission grooves, of the first metal layer, and limiting slots corresponding to the beam width limiting grooves are formed in the positions, located on the two sides of the radiation slots, of the first metal layer; a waveguide blocking groove is further arranged between the second metal layer and the first metal layer, the wave beam width limiting groove and the waveguide transmission groove are surrounded by the waveguide blocking groove, and the waveguide blocking groove and the first metal layer form a waveguide blocking cavity used for preventing electromagnetic waves from leaking from a gap between the first metal layer and the second metal layer. The waveguide antenna can solve the problem that the existing waveguide antenna which is assembled in a layered mode and is simple in structure is poor in gap tolerance.

Description

Technical Field

[0001] The present invention relates to the technical field of millimeter wave radar, and in particular to a millimeter wave waveguide antenna. Background Art

[0002] With the rapid development of ADAS technology, while its functions and performance are becoming stronger and stronger, the performance requirements for the sensors used are also getting higher and higher. As a very important sensor in the ADAS system, millimeter-wave radar inevitably puts forward new and higher requirements for its performance. Microstrip lines are widely used in millimeter-wave radars due to their low cost and simple processing. However, microstrip lines have large losses and narrow bandwidths. Replacing the original microstrip antennas with waveguide antennas with low losses and large bandwidths naturally becomes an important direction for breakthroughs in the performance of 77GHz millimeter-wave radars. Existing waveguide antennas are either simple in structure, but have poor tolerance for gaps caused by production and assembly processes, and a slight gap will cause serious deterioration in antenna performance. Or, although they can have a large tolerance for gaps caused by production and assembly, their structures are relatively complex, which is not conducive to production, processing and mass production. Therefore, there is an urgent need for a waveguide antenna with a simple structure and stable performance when there are certain gaps in the assembly. Summary of the invention

[0003] The present invention provides a millimeter wave waveguide antenna, which can solve the problem that the existing waveguide antenna with simple structure and layered assembly has poor gap tolerance.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a millimeter wave waveguide antenna, comprising: a first metal layer; a second metal layer, arranged on one side of the first metal layer and in contact with the first metal layer, characterized in that a waveguide transmission groove and beam width limiting grooves arranged on both sides of the waveguide transmission groove are arranged on the second metal layer facing the first metal layer, a plurality of radiation slots are opened at positions corresponding to the waveguide transmission slot on the first metal layer, limiting slots corresponding to the beam width limiting slots are arranged on both sides of the radiation slot on the first metal layer, and the beam width limiting slot and the limiting slot constitute a beam width limiting cavity for adjusting the beam width of the waveguide antenna in the horizontal direction;

[0005] A waveguide blocking groove is also arranged between the second metal layer and the first metal layer. The waveguide blocking groove surrounds the beam width limiting groove and the waveguide transmission groove. The waveguide blocking groove and the first metal layer form a waveguide blocking cavity for preventing electromagnetic waves from leaking from the gap between the first metal layer and the second metal layer. The beam width of the waveguide antenna in the horizontal direction can be adjusted by setting the position of the beam width limiting cavity, and it is relatively flexible.

[0006] By setting a number of radiation slots, the resonant frequency of the waveguide antenna can be adjusted to the required working frequency band, and by reasonably adjusting the distance of the radiation slot offset from the longitudinal center line of the waveguide transmission slot, the side lobes of the waveguide antenna radiation pattern meet the preset conditions.

[0007] By setting the waveguide stopping cavity, the waveguide antenna has a certain tolerance for the installation gap, which is convenient for production and assembly, thereby ensuring the stability and consistency of the antenna performance.

[0008] Preferably, the radiation slots are rectangular through slots, and are arranged in a staggered manner along the longitudinal midline of the waveguide transmission slot. By reasonably adjusting the spacing between the radiation slots, the beam of the waveguide antenna elevation pattern is directed to a preset direction.

[0009] Preferably, the radiation slot is parallel to or angled with the longitudinal midline of the waveguide transmission slot, and the resonant frequency of the waveguide antenna can be adjusted to a desired operating frequency band.

[0010] Preferably, the length of the beam width limiting slot is smaller than the length of the waveguide transmission slot.

[0011] Preferably, the beam width limiting groove on the left side shares the first left side wall of the waveguide transmission groove with the waveguide transmission groove, and the beam width limiting groove on the right side shares the first right side wall of the waveguide transmission groove with the waveguide transmission groove, and the first left side wall and the first right side wall have the same width, the beam width limiting groove on the left side shares the second left side wall of the beam width limiting groove with the waveguide blocking groove on the left side, and the beam width limiting groove on the right side shares the second right side wall of the beam width limiting groove with the waveguide blocking groove on the right side, and the second left side wall and the second right side wall have the same width, and the structure is compact, which facilitates the processing of the waveguide transmission groove, the beam width limiting groove and the waveguide blocking groove, and can ensure that the spacing between the waveguide transmission groove and the beam width limiting grooves on the left and right sides and the waveguide blocking groove are equal.

[0012] Preferably, the waveguide blocking groove includes two longitudinal blocking grooves located outside the beam width limiting groove and a transverse blocking groove located outside the end of the waveguide transmission groove. The beam width limiting groove and the waveguide transmission groove can be surrounded by the longitudinal blocking grooves and the transverse blocking grooves to prevent electromagnetic waves from leaking from the gap between the first metal layer and the second metal layer, thereby ensuring the stable performance of the waveguide antenna.

[0013] Preferably, the end of the beam width limiting groove is connected to the transverse blocking groove, which can reduce the difficulty of processing and facilitate one-piece molding.

[0014] Preferably, the mutually bonding surfaces of the first metal layer and the second metal layer are both smooth metal surfaces, which can reduce the loss during electromagnetic wave transmission.

[0015] Preferably, a rectangular ridge is provided in the middle of the bottom of the waveguide transmission groove to meet the needs of different forms of high-frequency signal transmission.

[0016] Preferably, the cross-sections of the waveguide transmission slot, beam width limiting slot and waveguide blocking slot are rectangular, which is conducive to the transmission of electromagnetic waves.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] By setting the position of the beam width limiting cavity, the horizontal beam width of the waveguide antenna can be adjusted flexibly; by setting a number of radiation slots, the resonant frequency of the waveguide antenna can be adjusted to the required working frequency band, and by reasonably adjusting the distance of the radiation slot offset from the longitudinal center line of the waveguide transmission slot, the side lobes of the waveguide antenna radiation pattern meet the preset conditions; by setting the waveguide blocking cavity, the waveguide antenna has a certain tolerance for the installation gap, which is convenient for production and assembly, thereby ensuring the stability and consistency of the antenna performance; the structure is simple, with fewer components, and there is no structure that needs to be processed separately, which greatly reduces the complexity and production difficulty of the mold, thereby reducing the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram showing the structure of a millimeter wave antenna according to an embodiment of the present invention is shown.

[0020] Figure 2 A cross-sectional view of a millimeter wave waveguide antenna according to an embodiment of the present invention is shown.

[0021] Figure 3 A top view of the first metal layer of the millimeter wave waveguide antenna according to an embodiment of the present invention is shown.

[0022] Figure 4 A cross-sectional view of the second metal layer of the millimeter wave waveguide antenna according to an embodiment of the present invention is shown.

[0023] Figure 5 A perspective view showing the second metal layer of the millimeter wave waveguide antenna according to an embodiment of the present invention

[0024] Figure 6 A top view of the second metal layer of the millimeter wave waveguide antenna according to an embodiment of the present invention is shown.

[0025] Figure 7 The S parameter curve of the millimeter wave waveguide antenna according to the embodiment of the present invention is shown as follows:

[0026] Figure 8 The millimeter wave waveguide antenna radiation pattern according to the embodiment of the present invention is shown.

[0027] Reference numerals:

[0028] 1. First metal layer, 11. Radiation gap, 12. Limiting gap, 2. Second metal layer, 21. Waveguide transmission slot, 211. Rectangular ridge, 213. First left side wall, 214. First right side wall, 22. Beam width limiting slot, 221. Beam width limiting cavity, 222. Second left side wall, 223. Second right side wall, 23. Waveguide blocking slot, 231. Waveguide blocking cavity, 232. Longitudinal blocking slot, 233. Transverse blocking slot. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0030] The present invention aims to solve the problem that the existing waveguide antennas with simple structure and layered assembly have poor gap tolerance. Figure 1-8 As shown, the following technical solution is provided: a millimeter wave waveguide antenna, comprising: a first metal layer 1; a second metal layer 2, which is arranged on one side of the first metal layer 1 and is in contact with the first metal layer 1, a waveguide transmission slot 21 and a beam width limiting slot 22 arranged on both sides of the waveguide transmission slot 21 are arranged on the second metal layer 2 on the side facing the first metal layer 1, a plurality of radiation slots 11 are opened at positions corresponding to the waveguide transmission slot 21 on the first metal layer 1, limiting slots 12 corresponding to the beam width limiting slots 22 are arranged on both sides of the radiation slots 11 on the first metal layer 1, and the beam width limiting slots 22 and the limiting slots 12 constitute a beam width limiting cavity 221 for adjusting the beam width of the waveguide antenna in the horizontal direction;

[0031] A waveguide blocking groove 23 is also arranged between the second metal layer 2 and the first metal layer 1. The waveguide blocking groove 23 surrounds the beam width limiting groove 22 and the waveguide transmission groove 21. The waveguide blocking groove 23 and the first metal layer 1 form a waveguide blocking cavity 231 for preventing electromagnetic waves from leaking from the gap between the first metal layer 1 and the second metal layer 2. The beam width of the waveguide antenna in the horizontal direction can be adjusted by setting the position of the beam width limiting cavity 221, and it is relatively flexible.

[0032] By setting a plurality of radiation slots 11, the resonant frequency of the waveguide antenna can be adjusted to the required working frequency band, and by reasonably adjusting the distance of the radiation slot 11 offset from the longitudinal center line of the waveguide transmission slot 21, the side lobes of the waveguide antenna radiation pattern meet the preset conditions.

[0033] The waveguide stopping cavity 231 is provided to allow the waveguide antenna to have a certain tolerance for the installation gap, which is convenient for production and assembly, thereby ensuring the stability and consistency of the antenna performance.

[0034] Specifically, the first metal layer 1 and the second metal layer 2 are processed separately and can be formed by stamping metal plates. Of course, the upper side of the second metal layer 2 can be processed by metal CNC because multiple grooves are required. The second metal layer 2 can also be made by composite metal layers on the surface of the plastic base. It can be selected according to needs, and it is only necessary to ensure that the mutually bonded surfaces of the first metal layer 1 and the second metal layer 2 are smooth metal surfaces, which can reduce the loss during electromagnetic wave transmission, and the gap between the first metal layer 1 and the second metal layer 2 is as small as possible.

[0035] In this embodiment, after the electromagnetic wave is transmitted to the waveguide transmission slot 21, the electromagnetic wave is radiated out through the radiation gap 11, playing the role of a waveguide antenna, wherein, Figure 1 and 3 As shown, the radiation slots 11 are rectangular through slots, and the sizes of the radiation slots 11 can be consistent or inconsistent, and the radiation slots 11 are arranged in a staggered manner along the longitudinal midline of the waveguide transmission slot 21. By reasonably adjusting the spacing between the radiation slots 11, the beam of the waveguide antenna elevation pattern is directed to a preset direction. Among them, the cross-sections of the waveguide transmission slot 21, the beam width limiting slot 22 and the waveguide blocking slot 23 are rectangular, which is conducive to the transmission of electromagnetic waves.

[0036] like Figure 7 As shown, Figure 7 This is the S parameter curve of the waveguide antenna designed according to this embodiment. The antenna operating frequency band is 75.4GHz~82.3GHz, and the bandwidth is 6.9GHz@-10dB. It can be clearly seen from the figure that the bandwidth of the S parameter curve is relatively wide after adopting the technical solution in this embodiment.

[0037] like Figure 8 Shown is the radiation pattern of the waveguide antenna. Figure 8 There are four curves. The first curve on the top is a waveguide antenna with an operating frequency band of 77 GHz, phi=0deg, and a gap of 0 mm between the first metal layer 1 and the second metal layer 2. The second curve on the bottom is a waveguide antenna with an operating frequency band of 77 GHz, phi=0deg, and a gap of 0.2 mm.

[0038] Located in Figure 8 The third curve at the bottom is a waveguide antenna with an operating frequency band of 77 GHz, phi=90deg, and a gap of 0 mm between the first metal layer 1 and the second metal layer 2. The fourth curve on one side of the third curve is a waveguide antenna with an operating frequency band of 77 GHz, phi=90deg, and a gap of 0.2 mm between the first metal layer 1 and the second metal layer 2.

[0039] from Figure 8It can be seen that the gap between the waveguide antennas of the second curve and the fourth curve is 0.2 mm, but the first curve and the third curve, whose directional patterns have a gap of 0, have roughly the same shape, indicating that when there is a 0.2 mm gap between the first metal layer 1 and the second metal layer 2, the directional pattern of the waveguide antenna is little affected.

[0040] In this embodiment, the radiation slot 11 is parallel to or at an angle to the longitudinal center line of the waveguide transmission slot 21. By adjusting the direction of the radiation slot 11, the resonant frequency of the waveguide antenna can be placed in a required operating frequency band. For example, if the radiation slot 11 and the longitudinal center line of the waveguide transmission slot 21 form an angle of 5-10°, the direction and resonant frequency of the electromagnetic wave emitted from the radiation slot 11 can be adjusted.

[0041] In this embodiment, the waveguide transmission slot 21 is usually connected to the waveguide feeder of the waveguide antenna. The waveguide feeder will be routed according to actual needs. Therefore, the length of the waveguide transmission slot 21 is generally longer than the total length of the radiation slot 11. However, the length of the beam width limiting slot 22 has no requirements for routing, and its length is less than the length of the waveguide transmission slot 21. This can reduce the structural size and reduce the difficulty of production.

[0042] In order to facilitate the processing of the second metal layer 2, as Figure 4 As shown, the beam width limiting groove 22 on the left side shares the first left side wall 213 of the waveguide transmission groove 21 with the waveguide transmission groove 21, and the beam width limiting groove 22 on the right side shares the first right side wall 214 of the waveguide transmission groove 21 with the waveguide transmission groove 21, and the first left side wall 213 and the first right side wall 214 have the same width, the beam width limiting groove 22 on the left side shares the second left side wall 222 of the beam width limiting groove 22 with the waveguide blocking groove 23 on the left side, and the beam width limiting groove 22 on the right side shares the second right side wall 223 of the beam width limiting groove 22, and the second left side wall 222 and the second right side wall 223 have the same width, and the structure is compact, which is convenient for processing the waveguide transmission groove 21, the beam width limiting groove 22 and the waveguide blocking groove 23, and can ensure that the spacing between the waveguide transmission groove 21 and the beam width limiting grooves 22 and the waveguide blocking grooves 23 on the left and right sides is equal.

[0043] The beam width limiting slot 22 has the same width as the waveguide transmission slot 21, the ends are aligned, and the lengths are the same or different, and are used to adjust the beam width of the waveguide antenna in the horizontal direction.

[0044] like Figure 5As shown, the waveguide blocking groove 23 includes two longitudinal blocking grooves 232 located outside the beam width limiting groove 22 and a transverse blocking groove 233 located outside the end of the waveguide transmission groove 21. The longitudinal blocking grooves 232 and the transverse blocking grooves 233 can surround the beam width limiting groove 22 and the waveguide transmission groove 21 to prevent electromagnetic waves from leaking from the gap between the first metal layer 1 and the second metal layer 2, thereby ensuring the stability of the waveguide antenna performance. Among them, the end of the beam width limiting groove 22 is connected to the transverse blocking groove 233, which can reduce the difficulty of processing and facilitate integrated molding. The width and depth of the longitudinal blocking groove 232 and the transverse blocking groove 233 are kept consistent.

[0045] In this embodiment, if Figure 4-6 As shown, a rectangular ridge 211 is provided in the middle of the bottom of the waveguide transmission slot 21, which can meet the needs of high-frequency signal transmission in different forms.

[0046] Therefore, after adopting the technical solution in this embodiment, not only the structure of the waveguide antenna is reduced, but also the beam width of the waveguide antenna in the horizontal direction can be adjusted by setting the position of the beam width limiting cavity, and it is more flexible; by setting a number of radiation slots, the resonant frequency of the waveguide antenna can be adjusted to the required working frequency band, and by reasonably adjusting the distance of the radiation slot offset from the longitudinal center line of the waveguide transmission slot, the side lobe of the waveguide antenna radiation pattern meets the preset conditions; by setting the waveguide blocking cavity, the waveguide antenna has a certain tolerance to the installation gap, which is convenient for production and assembly, thereby ensuring the stability and consistency of the antenna performance.

[0047] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0048] In addition, in the present invention, descriptions such as "primary", "secondary", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "primary" or "secondary" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0049] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

Claims

1. A millimeter wave waveguide antenna, characterized in that: include: A first metal layer (1); A second metal layer (2) is arranged on one side of the first metal layer (1) and is bonded to the first metal layer (1), characterized in that a waveguide transmission groove (21) and beam width limiting grooves (22) arranged on both sides of the waveguide transmission groove (21) are arranged on the second metal layer (2) on the side facing the first metal layer (1), a plurality of radiation slots (11) are opened at positions corresponding to the waveguide transmission slots (21) on the first metal layer (1), and limiting slots (12) corresponding to the beam width limiting slots (22) are arranged on both sides of the radiation slots (11) on the first metal layer (1), and the beam width limiting slots (22) and the limiting slots (12) form a beam width limiting cavity (221) for adjusting the beam width of the waveguide antenna in the horizontal direction; A waveguide blocking groove (23) is also provided between the second metal layer (2) and the first metal layer (1), the waveguide blocking groove (23) surrounds the beam width limiting groove (22) and the waveguide transmission groove (21), and the waveguide blocking groove (23) and the first metal layer (1) form a waveguide blocking cavity (231) for preventing electromagnetic waves from leaking from the gap between the first metal layer (1) and the second metal layer (2).

2. The millimeter wave waveguide antenna according to claim 1, characterized in that: The radiation slots (11) are rectangular through slots, and the radiation slots (11) are arranged in a staggered manner along the longitudinal center line of the waveguide transmission slot (21).

3. The millimeter wave waveguide antenna according to claim 2, characterized in that: The radiation slot (11) is arranged parallel to or at an angle to the longitudinal midline of the waveguide transmission slot (21).

4. The millimeter wave waveguide antenna according to claim 1, characterized in that: The length of the beam width limiting slot (22) is smaller than the length of the waveguide transmission slot (21).

5. The millimeter wave waveguide antenna according to claim 1, characterized in that: The beam width limiting groove (22) on the left side shares the first left side wall (213) of the waveguide transmission groove (21) with the waveguide transmission groove (21), the beam width limiting groove (22) on the right side shares the first right side wall (214) of the waveguide transmission groove (21), the first left side wall (213) and the first right side wall (214) have the same width, the beam width limiting groove (22) on the left side shares the second left side wall (222) of the beam width limiting groove (22) with the waveguide blocking groove (23) on the left side, the beam width limiting groove (22) on the right side shares the second right side wall (223) of the beam width limiting groove (22), the second left side wall (222) and the second right side wall (223) have the same width.

6. The millimeter wave waveguide antenna according to claim 1, characterized in that: The waveguide blocking groove (23) comprises two longitudinal blocking grooves (232) located outside the beam width limiting groove (22) and a transverse blocking groove (233) located outside the end of the waveguide transmission groove (21).

7. The millimeter wave waveguide antenna according to claim 6, characterized in that: The end of the beam width limiting slot (22) is connected to the transverse blocking slot (233).

8. The millimeter wave waveguide antenna according to claim 1, characterized in that: The mutually bonded surfaces of the first metal layer (1) and the second metal layer (2) are both smooth metal surfaces.

9. The millimeter wave waveguide antenna according to claim 1, characterized in that: A rectangular convex ridge (211) is arranged in the middle of the bottom of the waveguide transmission groove (21).

10. The millimeter wave waveguide antenna according to claim 1, characterized in that: The cross sections of the waveguide transmission slot (21), the beam width limiting slot (22) and the waveguide blocking slot (23) are rectangular.

Images