Power dividing horn antenna and vehicle-mounted millimeter wave radar

Abstract

The power dividing horn antenna comprises a waveguide tube and a horn mouth which are in butt joint with each other, the horn mouth is provided with a corresponding long edge and a corresponding short edge, one side of the horn mouth is in butt joint with the waveguide tube, and the other side of the horn mouth is provided with an interval groove. The two unit barrels are arranged in a spaced mode in the long edge direction through the partition groove; one end, far away from the waveguide tube, of the horn mouth is a tail end, the long side has a span L1 at the tail end, the widest part of the interval groove has a span L4 in the long side direction, and the span L4 is smaller than one half of the span L1. The power division horn antenna is simple in structure, can obtain better azimuth beam width, and meets the detection range requirement of millimeter wave radar.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of signal detection, in particular to a power-dividing horn antenna and a vehicle-mounted millimeter wave radar. BACKGROUND

[0002] 4D millimeter wave radar antennas require antennas with wider impedance bandwidth. Therefore, millimeter wave radars currently mostly use waveguide antennas. Horn antennas, as the simplest waveguide antennas, have been used in 4D millimeter wave radars. Automotive millimeter wave radars require antennas with wide azimuth beam width (E-plane) to detect targets, and antennas with narrow elevation beam width (H-plane) to reduce the influence of ground reflected waves. Due to different application scenarios, few studies focus on expanding the beam width of horn antennas, and most work focuses on suppressing the beam width.

[0003] In order to obtain a wider azimuth beam width, some existing technologies use horn antenna arrays to solve this problem, but horn arrays require multiple plastic metalized plates (three-layer plates and above) for processing, and these circuit boards need to be separately processed before being bonded together. This method will bring more errors and higher processing costs. There is also a solution of slotted waveguide to achieve the ideal radar pattern, but the impedance bandwidth of this solution is narrow. CONTENT OF THE UTILITY MODEL

[0004] The present application provides a horn antenna with simple structure and better azimuth beam width to meet the detection range requirements of millimeter wave radars.

[0005] The present application provides a power-dividing horn antenna, which comprises a waveguide and a horn mouth that are mutually butted, the horn mouth has corresponding long and short sides, one side of the horn mouth is butted with the waveguide, the other side has a spacing groove, and the horn mouth is divided into two unit cylinders arranged at intervals along the long side direction through the spacing groove.

[0006] The end of the horn mouth away from the waveguide is a terminal, the long side has a span L1 at the terminal, along the long side direction, the widest part of the spacing groove has a span L4, and the span L4 is less than one half of the span L1.

[0007] The following also provides several optional modes, but not as an additional limitation to the above general scheme, but only as a further supplement or preference, without technical or logical contradiction, each optional mode can be combined with the above general scheme, and multiple optional modes can also be combined.

[0008] In one of the embodiments, the power-dividing horn antenna has a height direction extending from the waveguide to the horn mouth, the spacing groove has a closed groove bottom at one end in the height direction, and the spacing groove extends by an equal span from the groove bottom to an end opening to the horn mouth.

[0009] In one of the embodiments, the spacing groove has a height H4, and the span L1 is 2 times the height H4.

[0010] In one of the embodiments, the height H4 is less than or equal to 4 mm.

[0011] In one of the embodiments, the span L4 is 1 / 10 to 1 / 4 of the span L1.

[0012] In one of the embodiments, the horn mouth includes a transition section and two unit barrels, the two unit barrels are a first unit barrel and a second unit barrel respectively, each unit barrel is in communication with one side of the transition section in abutment, and the horn mouth as a whole has a U-shaped structure.

[0013] In one of the embodiments, the waveguide includes an extension section in abutment with the transition section, and a converging section converging in shape in the long-side direction, and an end aperture size of the converging section corresponds to a WR10 waveguide or a WR12 waveguide.

[0014] In one of the embodiments, the extension section converges in a stepped structure in the long-side direction.

[0015] In one of the embodiments, in the long-side direction, the extension section has a span L2, the converging section has a span L3, and the span L2 is 1.5 times the span L3.

[0016] In one of the embodiments, the waveguide has a span W2 in the short-side direction, and the extension section has a height H2, and a ratio of the span W2 to the height H2 is 1:(0.8-1.2).

[0017] In one of the embodiments, the power-dividing horn antenna as a whole is a corner horn antenna, and the horn mouth has an outward expansion trend in both the E plane and the H plane relative to the waveguide; wherein the long side corresponds to the H plane, and the short side corresponds to the E plane.

[0018] The application also provides a vehicle-mounted millimeter wave radar including an antenna, and the antenna is the power-dividing horn antenna.

[0019] The power-dividing horn antenna utilizes interval grooves to implement power division, realizes separation of electromagnetic fields, effectively widens the azimuth plane beam width, and has simple overall structure and small size. Compared with existing millimeter wave radar antenna units, the power-dividing horn antenna has a smaller radiation aperture, can be processed by using a single-layer plate or a double-layer plate, and thus has a significantly reduced processing cost compared with three-layer or four-layer antennas, is conducive to large-scale processing and manufacturing, and has excellent radar pattern characteristics. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0021] Figure 1 It is a perspective view of the power-dividing horn antenna in an embodiment of the present application.

[0022] Figure 2 It is a front view of the power-dividing horn antenna. Figure 1

[0023] Figure 3 It is a side view of the power-dividing horn antenna. Figure 1

[0024] Figure 4 It is a top view of the power-dividing horn antenna. Figure 1

[0025] Figure 5 It is a schematic diagram of the internal electric field of the power-dividing horn antenna in an embodiment of the present application.

[0026] Figure 6 It is a schematic diagram of the azimuth plane beam width of the power-dividing horn antenna in an embodiment of the present application.

[0027] Figure 7 It is a schematic diagram of the two-layer mold during injection molding of the power-dividing horn antenna in an embodiment of the present application.

[0028] Figure 8 It is an internal schematic diagram of the two-layer mold. Figure 7

[0029] Figure 9 It is a schematic diagram of a conventional one-to-two horn antenna.

[0030] Figure 10 It is a schematic diagram of the S11 index of the power-dividing horn antenna in an embodiment of the present application.

[0031] Figure 11 ​​​​A schematic diagram of the azimuth beam width of the power-dividing horn antenna at different frequency points in an embodiment of the present application;

[0032] Figure 12 A schematic diagram of the elevation beam width of the power-dividing horn antenna at different frequency points in an embodiment of the present application;

[0033] Figure 13 A schematic diagram of the comparison between the power-dividing horn antenna and the conventional one-dividing-two horn antenna in an embodiment of the present application.

[0034] The element reference numbers are as follows:

[0035] 100, waveguide; 110, converging section; 120, extending section;

[0036] 200, horn mouth; 210, first unit cylinder; 220, second unit cylinder; 230, spacing groove; 240, transition section;

[0037] 300, mold; 310, first unit mold; 320, second unit mold. DETAILED DESCRIPTION

[0038] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a number of ways other than those specifically described herein, and it is to be understood that the present application is not limited to the specific embodiments disclosed, but is open to equivalents.

[0039] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there can be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there can be an intervening element. The terms "vertical", "horizontal", "up", "down", "left", "right", and similar expressions used in the description of the specification are used for the purpose of illustration only and are not intended to indicate the sole orientation of the embodiments.

[0040] In addition, the terms "first", "second", and the like are used only for descriptive purposes and do not indicate or imply relative importance or a quantity of the indicated technical features. Thus, features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0041] In the present application, unless specifically defined and limited otherwise, the first feature is "on", "under", "above" or "over" the second feature, which can be that the first feature is in direct contact with the second feature, or the first feature is indirectly in contact with the second feature through an intermediate medium. Moreover, the first feature is "above", "over" and "on" the second feature, which can be that the first feature is directly above or obliquely above the second feature, or only indicates that the first feature is higher than the second feature in horizontal height (or in a use state, or in a certain drawing perspective). The first feature is "below", "under" and "under" the second feature, which can be that the first feature is directly below or obliquely below the second feature, or only indicates that the first feature is lower than the second feature in horizontal height (or in a use state, or in a certain drawing perspective).

[0042] Unless otherwise defined, all technical and scientific terms used in the specification of the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used in the specification of the present application includes any and all combinations of one or more related listed items.

[0043] The prior art 4D millimeter wave radar antenna unit is in the form of a horn array, the antenna volume is large, the structure has many layers, and the manufacturing cost is high. The traditional horn antenna usually adjusts the beam width of the horn radiation mode by adjusting the horn height and the length-width ratio of the radiation surface. However, due to the limitation of the size of the radar, the horn height of the automobile millimeter wave radar cannot be increased indefinitely. In the case of fixed height, there is a critical value for improving the beam width by the length-width ratio of the radiation surface, and it is difficult to achieve the ideal beam width.

[0044] Referring to Figures 1-4 An embodiment of the present application provides a power division horn antenna, which comprises a waveguide 100 and a horn mouth 200 that are mutually butted. The horn mouth 200 has a rectangular cross-sectional shape as a whole and has corresponding long and short sides. One side of the horn mouth 200 is butted with the waveguide 100, and the other side has a spacing groove 230 and is divided into two unit cylinders that are spaced apart along the long side direction, namely a first unit cylinder 210 and a second unit cylinder 220, through the spacing groove 230.

[0045] The horn mouth 200 is a U-shaped structure as a whole and comprises a transition section 240 and two unit cylinders. The two unit cylinders are butted and communicated with one side of the transition section 240, and the other side of the transition section 240 is butted and communicated with the waveguide 100.

[0046] The power division horn antenna of the embodiment can achieve a two-way power division function through the interval groove 230. Compared with the traditional power division mode, under the condition of the same aperture length (the span L1 of the long side), a wider azimuth beam width and a narrower elevation beam width can be achieved, the gain remains consistent, and the requirements of the millimeter wave radar for the wide azimuth beam and the slightly narrow elevation beam are better met.

[0047] The end of the horn mouth 200 away from the waveguide tube 100 is the terminal end. The long side has a span L1 at the terminal end, and the short side has a span W1 at the terminal end. In the long side direction, the widest part of the interval groove 230 has a span L4, and the span L4 is less than one half of the span L1.

[0048] The power division horn antenna has a height direction extending from the waveguide tube 100 to the horn mouth 200. In the height direction, the interval groove 230 has a closed groove bottom at one end. The interval groove 230 extends by an equal span from the groove bottom to the terminal end of the horn mouth 200, and the interval groove 230 has a height H4.

[0049] The existing two-way horn antenna (for example Figure 9 As shown, the dashed line represents the two-layer boundary part during processing. The interval of the two unit barrels has a large change in the height direction. After extending by an equal span, the interval is significantly narrowed near the terminal end, and the two unit barrels are almost connected. The interval groove 230 of the embodiment extends by an equal span, and different performance can be obtained compared with the existing two-way horn antenna.

[0050] The change of the span L4 and the height H4 of the interval groove 230 can adjust the directivity pattern of the power division horn antenna. For example, the adjustment of the span L4 can adjust the matching of the power divider. In the preferred mode, the span L4 is one tenth to one fourth of the span L1, for example, one tenth of the span L1.

[0051] The relative relationship between the height H4 and the span L1 can be changed to adjust the gain and beam width of the power division horn antenna to meet the scene requirements. For example, in one embodiment, the span L1 is 2 times the height H4, and better gain can be obtained. Considering the size and processing technology, the height H4 is less than or equal to 4 mm, which can ensure the feasibility of injection molding. If it exceeds 5 mm, the processing difficulty will be increased.

[0052] In one embodiment, the waveguide tube 100 includes an extension section 120 connected to the transition section 240 and a closing section 110 with a shape converging in the long side direction. The extension section has a height H2, and the closing section 110 has a height H3. The extension section 120 converges in the long side direction by using a stepped structure. In the long side direction, the extension section 120 has a span L2, and the closing section 110 has a span L3. The span L2 is 1.5 times the span L3.

[0053] The end aperture size of the tapered section 110 corresponds to a WR10 waveguide (2.54mm*1.27mm) or a WR12 (3.1mm*1.55mm) waveguide, which is more convenient for matching with other components having standard sizes, thereby improving its versatility.

[0054] In one embodiment, the waveguide tube 100 has a span W2 in the short direction, and the span W2 is close to or the same as the height H2, for example, the ratio of the span W2 to the height H2 is 1:(0.8-1.2).

[0055] Referring to Figure 5 The internal electric field diagram of the power-dividing horn antenna is shown, and the electromagnetic wave of the power-dividing horn antenna of the embodiment can be divided into two paths to realize the function of a one-to-two power divider. The two paths of signals are respectively radiated in free space, and the required azimuth plane (E-plane) wide beam form of the millimeter wave radar is realized through the superposition principle.

[0056] In one embodiment, the horn antenna is an angular pyramid horn antenna in terms of its overall configuration, and the horn mouth 200 has an outward expansion trend in the E-plane and the H-plane relative to the waveguide tube; wherein the long side corresponds to the H-plane, and the short side corresponds to the E-plane. When in use, the long side is placed vertically, and the posture is substantially as shown in Figure 6 .

[0057] The various parts of the power-dividing horn antenna of the present application can be processed by a plastic metallization process, that is, after plastic injection molding, the surface is plated with copper, gold or silver. This can reduce weight and cost.

[0058] Referring to Figure 7 and Figure 8 , the power-dividing horn antenna of the present application can be injection molded by using a mold 300. According to the shape characteristics, a two-layer processing method is adopted, that is, the mold 300 includes a first unit mold 310 and a second unit mold 320. The first unit mold 310 is used to form two unit cylinder parts, and the second unit mold 320 is used to form the remaining parts. After each layer is injection molded, they are bonded by welding, for example, each layer can be electroplated with copper, and the two layers are combined together by SMT and the like.

[0059] Referring to Figure 10 , it is tested that the power-dividing horn antenna of the present application realizes a full-band reflection coefficient of 76-81GHz less than -15dB.

[0060] Referring to Figure 11 and Figure 12 , the specific radiation performance indicators of each frequency point of the power-dividing horn antenna of the present application are shown, wherein the azimuth plane and the elevation plane -5dB beam width are 103.5° (for example Figure 6The horn antenna has a 3dB beam width of ±40 degrees, and the radiation pattern is suitable for millimeter wave radar. At 79GHz, the radiation gain at θ=0° is 11.5dBi, which also indicates that the horn antenna has stable radiation characteristics in the full frequency band.

[0061] Referring to Figure 13 Compared with the conventional horn antenna, the horn antenna has a wider azimuth beam width, and the 3dB beam width reaches ±40 degrees.

[0062] The application also provides a vehicle-mounted millimeter wave radar comprising the horn antenna of the above embodiments. The horn antenna effectively widens the azimuth beam width. Compared with the antenna array, the overall structure is simpler and smaller.

[0063] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not contradict, they should be considered as falling within the scope of the present disclosure. When the technical features in different embodiments are embodied in the same figure, it is considered that the figure also discloses the combination of the embodiments involved.

[0064] The above embodiments only express several implementation manners of the application, and the description is specific and detailed, but it should not be considered as a limitation on the patent protection scope of the application. It should be pointed out that for those skilled in the art, without departing from the concept of the application, some modifications and improvements can be made, which are all within the protection scope of the application. Therefore, the patent protection scope of the application should be subject to the appended claims.

Claims

1. A power splitting horn antenna, characterized in that: It includes a waveguide tube and a bell mouth that are connected to each other, the bell mouth has corresponding long sides and short sides, one side of the bell mouth is connected to the waveguide tube, and the other side has a spacing groove, and is divided into two unit tubes arranged at intervals along the long side direction by the spacing groove; The end of the flare away from the waveguide is the end, and the long side has a span L1 at the end. Along the long side, the widest part of the spacing groove has a span L4, and the span L4 is less than half of the span L1.

2. The power dividing horn antenna according to claim 1, characterized in that: The power dividing horn antenna has a height direction extending from the waveguide tube toward the horn mouth, and one end of the spacing slot in the height direction is a closed slot bottom position. The spacing slot extends with equal span from the slot bottom position until it opens at the end of the horn mouth.

3. The power dividing horn antenna according to claim 2, characterized in that: The spacing groove has a height H4, and a span L1 is twice the height H4.

4. The power dividing horn antenna according to claim 3, characterized in that: The height H4 is less than or equal to 4 mm.

5. The power dividing horn antenna according to claim 1, wherein: The span L4 is one tenth to one quarter of the span L1.

6. The power dividing horn antenna according to claim 1, characterized in that: The bell mouth includes a transition section and two unit tubes, the two unit tubes are respectively a first unit tube and a second unit tube, each unit tube is connected to one side of the transition section, and the bell mouth is a U-shaped structure as a whole; The waveguide tube includes an extension section docked with the transition section, and a closing section whose shape is narrowed in the long side direction. The end diameter of the closing section corresponds to that of the WR10 waveguide or the WR12 waveguide.

7. The power dividing horn antenna according to claim 6, characterized in that: The extension section is closed with a stepped structure in the long side direction; Along the long side direction, the extension section has a span L2, the closing section has a span L3, and the span L2 is 1.5 times the span L3.

8. The power dividing horn antenna according to claim 6, characterized in that: The waveguide has a span W2 in the short side direction, the extension section has a height H2, and a ratio of the span W2 to the height H2 is 1:(0.8-1.2).

9. The power dividing horn antenna according to claim 1, wherein: The power dividing horn antenna is a pyramidal horn antenna as a whole, and the horn mouth has an outward expansion trend on both the E plane and the H plane relative to the waveguide; wherein the long side corresponds to the H plane, and the short side corresponds to the E plane.

10. A vehicle-mounted millimeter-wave radar, characterized in that: The invention comprises an antenna, wherein the antenna is the power dividing horn antenna according to any one of claims 1 to 9.

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