Waveguide antenna, radar and automobile
By setting an absorbing layer on the waveguide structure, the problems of beamforming and isolation are solved, realizing a thin and efficient waveguide antenna design suitable for the 76-81GHz frequency range.
Patent Information
- Application Number
- CN202422541894.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-21
- Publication Date
- 2025-12-02
- Estimated Expiration
- 2034-10-21
AI Technical Summary
Traditional beamforming methods for waveguide antennas are not applicable, resulting in increased antenna thickness, complex manufacturing processes, and severe signal interference, making it difficult to achieve high-efficiency, wide-bandwidth beamforming and improve isolation.
An absorbing layer is placed on the waveguide structure without covering the radiation opening. The surface current is changed by the absorbing layer to achieve beamforming, reduce antenna pattern jitter and improve isolation. The shape and position of the absorbing layer can be flexibly adjusted to meet different requirements.
While achieving beamforming effect, it reduces antenna thickness, improves antenna array isolation and signal quality, and makes the structure more flexible and versatile.
Smart Images
Figure CN223625204U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of signal technology, and in particular to a waveguide antenna, radar, and automobile. Background Technology
[0002] With the development of autonomous driving technology, waveguide antennas, with their high efficiency and large bandwidth, are receiving increasing attention and application compared to traditional microstrip antennas. However, as waveguide antennas are a newly emerging form of radar antenna, traditional microstrip antenna design concepts and beamforming control methods are no longer applicable. How to concentrate the radiated energy of waveguide antennas more effectively within the functional region of millimeter-wave radar is a pressing research issue. Furthermore, due to the unique form of waveguide antennas, surface wave problems are more severe than those of microstrip antennas. These surface waves not only affect the isolation between channels but also influence the antenna's radiation pattern, increasing jitter or distorting the pattern.
[0003] To address beamforming, existing technologies employ a design that adds a concave wall above the radiating aperture (equivalent to adding a horn antenna to the original waveguide structure). However, this approach increases the antenna thickness, complicates manufacturing processes, and consequently raises costs. Furthermore, this method struggles to resolve signal interference issues caused by poor isolation between waveguide antennas within the antenna array. Utility Model Content
[0004] Therefore, it is necessary to provide a waveguide antenna that can both reduce antenna pattern jitter and improve the isolation between waveguide antennas in the antenna array.
[0005] To solve the above-mentioned technical problems, this application provides the following technical solution: a waveguide antenna, including a waveguide structure and an absorbing layer disposed on the waveguide structure, the waveguide structure having a radiation opening, the absorbing layer being arranged on the side of the radiation opening, and the absorbing layer not covering the radiation opening.
[0006] It is understandable that by setting an absorbing layer on the waveguide structure, the surface current of the waveguide structure is altered by the absorbing layer. Firstly, beamforming is achieved, which helps reduce antenna pattern jitter. Secondly, the isolation between waveguide antennas in the antenna array is improved. The shape of the absorbing layer's uncovered radiating opening and the relative position between the absorbing layer and the radiating opening can be set according to different beamforming and / or isolation requirements, thus making the waveguide antenna more flexible and versatile.
[0007] Furthermore, since the absorbing layer is directly placed on the waveguide structure, the thickness of this waveguide antenna is much lower than that of existing waveguide antennas that change the radiation opening, making this waveguide antenna thinner.
[0008] In one embodiment, the thickness of the absorbing layer does not exceed 3 mm.
[0009] In this way, the thickness of the waveguide antenna can be minimized while meeting beamforming and / or isolation requirements.
[0010] In one embodiment, the absorbing layer has a window that exposes a radiation opening, the projection of which in the horizontal direction is formed by at least one combination of straight line segments and curved segments.
[0011] This allows for greater flexibility in the shape of the window to meet different beamforming and / or isolation requirements.
[0012] In one embodiment, in the horizontal direction of projection, at least one radiating opening is located within the projection of the window, wherein multiple radiating openings located within the same window constitute a group of radiating openings.
[0013] This configuration allows for greater versatility in the structure of the waveguide antenna, while meeting different beam requirements and / or isolation requirements.
[0014] In one embodiment, the window forms a projection surface on a horizontal plane, and the projection surface is defined by a first bisector, a second bisector, and a directional point. The directional point is the intersection of the first bisector and the second bisector. The first bisector is a bisector of the projected area of the projection surface in the horizontal direction, and the second bisector is a bisector of the projected area of the projection surface in the vertical direction.
[0015] The waveguide antenna is defined by a beam target position, and the relative position of the azimuth point with respect to the vertical center line of the waveguide is determined according to the beam target position.
[0016] It is understandable that by confirming the azimuth point of the window on the horizontal projection, the relative position of the azimuth point with respect to the vertical center line of the waveguide can be adjusted to achieve different beam direction requirements. Compared with existing technologies, its control is simple and easy to implement.
[0017] In one embodiment, the width of the window in the first direction is 3 to 10 mm, and the length of the window in the second direction is 18 to 30 mm. The first direction is the short side direction of the rectangular waveguide, and the second direction is the long side direction of the rectangular waveguide.
[0018] This configuration is used to accommodate waveguide antennas in the 76-81 GHz frequency band.
[0019] In one embodiment, the waveguide antenna is a slot antenna or a horn antenna.
[0020] Thus, the structure of this waveguide antenna is applied to slot antennas or horn antennas.
[0021] In one embodiment, the dielectric constant of the absorbing layer is in the range of 6 to 12, and the dielectric loss factor is in the range of 0.2 to 0.5.
[0022] This application also provides the following technical solution: a radar, including a circuit board, a radio frequency chip disposed on the circuit board, and the aforementioned waveguide antenna disposed on the circuit board.
[0023] It is understood that by applying the waveguide antenna of this application to the radar, the performance of the radar is improved compared with the prior art, and the compactness and lightweight of the radar are improved while maintaining high performance.
[0024] This application also provides the following technical solution: a car that includes the aforementioned radar.
[0025] It is understandable that installing the aforementioned radar on a car can significantly improve the car's safety.
[0026] Compared to existing technologies, by incorporating an absorbing layer onto the waveguide structure and altering the surface current of the waveguide, firstly, beamforming is achieved, which helps reduce antenna pattern jitter; secondly, the isolation between waveguide antennas in the antenna array is improved. The shape of the absorbing layer's uncovered radiating opening and its relative position to the opening can be customized to meet different beamforming and / or isolation requirements, making the waveguide antenna more flexible and versatile. Furthermore, because the absorbing layer is directly incorporated into the waveguide structure, the thickness of this waveguide antenna is significantly lower than that of existing waveguide antennas that modify the radiating opening, resulting in a thinner antenna. Attached Figure Description
[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0028] Figure 1 This is a schematic diagram of the waveguide antenna provided in this application;
[0029] Figure 2 for Figure 1 The top view of the waveguide antenna shown;
[0030] Figure 3 A comparison diagram of the azimuth planes of three slot antennas with different structures;
[0031] Figure 4 This application provides a schematic diagram of the structure of a waveguide antenna array.
[0032] Figure 5 for Figure 4 The diagram shows a comparison of the isolation between a waveguide antenna array and an existing waveguide antenna array without an absorbing layer.
[0033] Figure 6 for Figure 4 The image shows a comparison of the waveguide antenna array and an existing waveguide antenna array without an absorbing layer in the transmit / receive combining direction.
[0034] Figure 7 A schematic diagram of another waveguide antenna provided in this application.
[0035] The component labels are as follows:
[0036] 100. Waveguide antenna; 10. Waveguide structure; 11. Radiation opening; 20. Absorbing layer; 21. Window; 200. Waveguide antenna array. Detailed Implementation
[0037] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.
[0038] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application's specification are for illustrative purposes only and do not represent the only possible implementation.
[0039] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0040] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0041] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items.
[0042] Please see Figure 1 This application provides a waveguide antenna 100, which includes a waveguide structure 10 and an absorbing layer 20 disposed on the waveguide structure 10. The waveguide structure 10 has radiation openings 11. In this embodiment, the number of radiation openings 11 is eight. Of course, in other embodiments, the number of radiation openings 11 can also be other than eight. Figure 7 In this structure, there is one radiating opening 11. The waveguide structure 10 can adopt an existing structure, which typically includes a metal plate on which the radiating opening 11 is formed. The absorbing layer 20 is located above the uppermost metal plate. The absorbing layer 20 is arranged on the side of the radiating opening 11, and the absorbing layer 20 does not cover the radiating opening 11.
[0043] By setting an absorbing layer 20 on the waveguide structure 10, the surface current of the waveguide structure 10 is changed by the absorbing layer 20. First, beamforming is achieved, which helps to reduce antenna pattern jitter. Second, the isolation between waveguide antennas in the antenna array is improved. The shape of the absorbing layer 20 not covering the radiation opening 11 and the relative position between the absorbing layer 20 and the radiation opening 11 can be set according to different beamforming requirements and / or isolation requirements, thus making the waveguide antenna 100 more flexible and versatile.
[0044] Furthermore, since the absorbing layer 20 is directly disposed on the waveguide structure 10, the thickness of the waveguide antenna 100 is much lower than that of the waveguide antenna 100 in the prior art that changes the radiation opening 11. Therefore, the waveguide antenna 100 is thinner.
[0045] It should be noted that in the prior art, the thickness of the concave wall added above the radiating opening 11 is not less than 10 mm, depending on the beamforming requirements to be achieved. In this application, although the waveform shaping effect is related to the thickness of the absorbing layer, and the thicker the absorbing layer 20, the more obvious the beam narrowing effect, experimental verification shows that under the same beamforming requirements, the thickness of the absorbing layer 20 used is much less than 10 mm. In one embodiment, the thickness of the absorbing layer 20 does not exceed 3 mm. By setting the thickness of the absorbing layer 20, the overall thickness of the waveguide antenna 100 can be minimized while achieving the beamforming and / or isolation requirements.
[0046] The dielectric constant (DK) of the absorbing layer 20 ranges from 6 to 12, and the dielectric loss factor (DF) ranges from 0.2 to 0.5, for example, DK = 9.4 and DF = 0.34. By limiting the range of dielectric constant and dielectric loss factor of the absorbing layer 20 of the waveguide antenna 100 applicable to this application, it is helpful to improve the overall performance of the antenna.
[0047] The absorbing layer 20 has a window 21 that exposes the radiation opening 11. In the horizontal direction, the projection of the window 21 is formed by at least one combination of straight line segments and curved segments. In one embodiment, the projection of the window 21 in the horizontal direction is rectangular; in other embodiments, the projection can also be circular, serrated, or irregularly shaped. Specifically, the window 21 can be configured with different shapes according to different beamforming requirements and / or isolation requirements. Besides the shape, the length of the window 21 and its position on the waveguide structure 10 can also be adjusted to achieve different beamforming and / or isolation requirements.
[0048] In this embodiment, the projection of the radiating opening 11 in the horizontal direction is a slot. Specifically, the waveguide antenna 100 is a slot antenna. As mentioned above, in this embodiment, the number of radiating openings 11 is eight. The eight radiating openings 11 are all located within the projection of the window 21 in the horizontal direction. In other embodiments, the window 21 may also be set to two or more, wherein the projection of each window 21 in the horizontal direction covers one or more radiating openings 11. For ease of description, multiple radiating openings 11 located within the same window 21 can be grouped into a radiating opening group, such as... Figure 1 In the illustrated embodiment, eight radiating openings are combined to form a radiating opening group. This arrangement allows for greater versatility in the structure of the waveguide antenna 100 while meeting different beamforming and / or isolation requirements.
[0049] As mentioned above, different beamforming requirements can be met by changing the shape of the absorbing layer 20 covering the radiating opening 11 and the relative position between the absorbing layer 20 and the radiating opening 11. In one embodiment, the width of the window 21 in the first direction ranges from 3 to 10 mm, and the length of the window 21 in the second direction ranges from 18 to 30 mm. The first direction is the direction of the short side of the rectangular waveguide, and the second direction is the direction of the long side of the rectangular waveguide. This configuration is used to adapt the waveguide antenna 100 to the frequency range of 76-81 GHz.
[0050] Since the influence of surface current and radiation on the waveguide structure 10 is greater in the azimuth direction than in the elevation direction, beamforming mainly considers the azimuth direction. The azimuth beamforming of the waveguide antenna 100 is achieved using the relative positions of window 21 and radiation opening 11 in the horizontal direction. Specifically, window 21 forms a projection plane on the horizontal plane, within which are defined a first bisector, a second bisector, and an azimuth point. The azimuth point is the intersection of the first and second bisectors. The first bisector is the line that bisects the projected area based on the projection plane in the horizontal direction (the horizontal direction is the X-axis direction of a coordinate system established based on the horizontal and vertical centerlines of the waveguide, where the X-axis direction is the direction of the horizontal centerline of the waveguide, and the Y-axis direction is the direction of the vertical centerline of the waveguide). The second bisector is the line that bisects the projected area based on the projection plane in the vertical direction (the horizontal direction is the Y-coordinate direction of the coordinate system established based on the projection plane). The waveguide antenna 100 is defined with a beam target position, which is the position in which the waveguide antenna 100 is expected to point in a specific direction, which is the direction of beam radiation. The relative position of the azimuth point with respect to the vertical centerline of the waveguide is determined based on the beam target position. By confirming the azimuth point on the horizontal projection of the window 21, the relative position of the azimuth point with respect to the vertical centerline of the waveguide in the azimuth direction can be adjusted to achieve different beam direction requirements. Compared with the prior art, its control is simple and easy to implement.
[0051] To facilitate understanding of the effect of the absorbing layer 20 on the beam direction, a comparative explanation is provided using the structures of three different waveguide antennas 100. The first type of waveguide antenna 100: [Example 100] Figure 1 The waveguide antenna 100 shown includes a waveguide structure 10 and an absorbing layer 20 disposed on the waveguide structure 10. The azimuth point on the projection plane of its window 21 is located above the vertical centerline of the waveguide. Figure 2 for Figure 1 Top view, Figure 2 The dashed line xx represents the vertical centerline of the waveguide, which serves as the baseline. The dashed box indicates the waveguide, and the point indicated by arrow A is the azimuth point (a virtual point). The second type of waveguide antenna... Figure 1The difference between the waveguide antenna 100 shown is that the azimuth point is located below the vertical centerline of the waveguide, unlike the third type of waveguide antenna. Figure 1 The difference in the waveguide antenna 100 shown is that it does not have an absorbing layer. Please see... Figure 3 , Figure 1 The left-biased beam corresponds to the first type of waveguide antenna 100, the right-biased beam corresponds to the second type of waveguide antenna, and the original pattern beam corresponds to the third type of waveguide antenna.
[0052] Please see Figure 4 The waveguide antenna array 200 shown consists of eight waveguide antennas. The absorbing layer 20 is a single, integral structure covering the waveguide structures 10 of the eight waveguide antennas. The eight waveguide structures 10 form a module. Of course, in other embodiments, the number of waveguide antennas can be set according to the actual application scenario. In this embodiment, the waveguide antenna is a slot antenna; in other embodiments, the waveguide antenna can also be other types of waveguide antennas.
[0053] The waveguide antenna arrays described above, which have the first type of waveguide antenna 100 and the waveguide antenna array with the third type of waveguide antenna, are used as simulation objects. Please refer to [link / reference]. Figure 5 Using the isolation between the receiving antenna RX1 and receiving antenna RX2 channels as a reference, it can be found that the isolation between the third type of waveguide antenna is -25dB, while the isolation between the first type of waveguide antenna 100 is -35dB. Therefore, the first type of waveguide antenna can improve the isolation between antennas while performing beamforming. Please refer to... Figure 6 When the two types of waveguide antennas 100 are placed on the arrayed 4 transmit and 4 receive waveguide antenna 100 radar, it can be seen that the first type of waveguide antenna 100 has a more obvious beamforming effect in the azimuth plane. In the core functional area of -55 to 0°, it can have a gain increase of about 5dB, which makes the angle radar have a better signal-to-noise ratio in the functional area.
[0054] Please see Figure 7 The waveguide antenna 100 is a horn antenna with a horn-shaped radiating opening. In this embodiment, the horizontal cross-section of the radiating opening is square; in other embodiments, the cross-section of the radiating opening can be circular or other shapes. Thus, the structure of the waveguide antenna 100 of this application can be applied not only to slot antennas but also to horn antennas to improve its applicability. Of course, the waveguide antenna 100 can also be other types of waveguide antennas to further enhance the breadth of application of the waveguide antenna structure of this application; details will not be elaborated here. Figure 7 The waveguide structure 10 of the horn antenna shown has only one radiation opening 11. In other embodiments, the horn antenna may have two or more radiation openings.
[0055] This application also provides a radar, specifically a millimeter-wave radar, comprising a circuit board, an RF chip mounted on the circuit board, and a waveguide antenna mounted on the circuit board. The structures of the circuit board and the RF chip can employ existing technologies, as can the arrangement and connection methods between the circuit board, the RF chip, and the waveguide antenna, which will not be detailed here. Figure 1 The slot antenna shown, Figure 7 The horn antenna shown.
[0056] As mentioned above, because the waveguide antenna of this application has good isolation and reduces antenna pattern jitter, the radar has excellent performance. Furthermore, because the waveguide antenna is thinner than existing technologies, the radar has the advantages of being compact and lightweight.
[0057] This application also provides a vehicle including a vehicle body, a drive system disposed within the vehicle body, etc. In addition, the vehicle also includes a radar with the aforementioned structure. By installing the aforementioned radar on the vehicle, the safety of the vehicle can be significantly improved.
[0058] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0059] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the patent protection scope of this application should be determined by the appended claims.
Claims
1. A waveguide antenna, characterized in that, The device includes a waveguide structure and an absorbing layer disposed on the waveguide structure. The waveguide structure has a radiation opening, and the absorbing layer is disposed on the side of the radiation opening, but does not cover the radiation opening. The absorbing layer has a window that exposes the radiation opening, and in the horizontal direction, the projection of the window is formed by at least one combination of straight line segments and curved segments.
2. The waveguide antenna according to claim 1, characterized in that, The thickness of the absorbing layer does not exceed 3 mm.
3. The waveguide antenna according to claim 1, characterized in that, In the horizontal direction of projection, at least one of the radiation openings is located within the projection of the window, wherein multiple radiation openings located within the same window constitute a radiation opening group.
4. The waveguide antenna according to claim 3, characterized in that, The window forms a projection surface on a horizontal plane. The projection surface is defined by a first bisector, a second bisector, and a directional point. The directional point is the intersection of the first bisector and the second bisector. The first bisector is a bisector of the projected area of the projection surface in the horizontal direction, and the second bisector is a bisector of the projected area of the projection surface in the vertical direction. The waveguide antenna is defined by a beam target position, and the relative position of the azimuth point with respect to the vertical center line of the waveguide is determined according to the beam target position.
5. The waveguide antenna according to claim 4, characterized in that, The width of the window in the first direction ranges from 3 to 10 mm, and the length of the window in the second direction ranges from 18 to 30 mm. The first direction is the short side direction of the rectangular waveguide, and the second direction is the long side direction of the rectangular waveguide.
6. The waveguide antenna according to claim 1, characterized in that, The waveguide antenna is either a slot antenna or a horn antenna.
7. The waveguide antenna according to claim 1, characterized in that, The dielectric constant of the absorbing layer ranges from 6 to 12, and the dielectric loss factor ranges from 0.2 to 0.
5.
8. A radar, characterized in that, It includes a circuit board, an RF chip disposed on the circuit board, and a waveguide antenna disposed on the circuit board as described in any one of claims 1-7.
9. A car, characterized in that, It includes the radar as described in claim 8.