Horn antenna and vehicle-mounted millimeter wave radar

Abstract

The utility model relates to a horn antenna and a vehicle-mounted millimeter wave radar, and the horn antenna comprises a waveguide tube and a horn mouth which is connected with the waveguide tube and is expanded outwards. One side, far away from the waveguide tube, of the horn mouth is a port part, the edge of the port part comprises two long edges which are oppositely arranged and two short edges which are connected between the two long edges, and the middle areas of the two long edges are provided with inward concave parts which are deviated in opposite directions. The horn antenna is simple in structure and easy to process, and a specific directional diagram required by the millimeter wave radar can be realized through the horn mouth; the overall size is small, and compared with a currently used millimeter wave radar antenna unit, the millimeter wave radar antenna unit has a smaller radiation aperture; the manufacturing cost is greatly reduced, and a single-layer board or a double-layer board can be used for processing, so that the processing cost is obviously reduced compared with that of a three-layer and four-layer antenna, and large-scale processing and manufacturing are facilitated; compared with a traditional single horn antenna, the antenna has more excellent radar directional diagram characteristics.

Description

TECHNICAL FIELD

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

[0002] 4D millimeter wave radar antennas require antennas with wider impedance bandwidth. Therefore, waveguide antennas are currently used in millimeter wave radars. 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, which can obtain a wider azimuth beam width and a narrower elevation beam width.

[0005] The horn antenna provided by the present application comprises a waveguide tube and a horn mouth connected with the waveguide tube and outwardly expanded in shape.

[0006] The side of the horn mouth away from the waveguide tube is a port part, and the edge of the port part comprises two long sides arranged oppositely and two short sides connected between the two long sides, wherein the middle region of the two long sides has inwardly offset recessed parts.

[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 the combination between multiple optional modes is also possible.

[0008] In one embodiment, the recessed part has a span L3 along the extension direction of the long side, and the span L3 is one-half wavelength of the horn antenna.

[0009] In one embodiment, the recessed part has a depth W3 along the extension direction of the short side, and the depth W3 is one-fourth wavelength of the horn antenna.

[0010] In one of the embodiments, the inner recesses of the two long sides are symmetrical to each other and are arranged at equal intervals in the extension direction of the long sides.

[0011] In one of the embodiments, the horn antenna is a corner horn antenna, the horn mouth has an outward expansion tendency in both E and H planes relative to the waveguide; wherein the long side corresponds to the H plane and the short side corresponds to the E plane.

[0012] In one of the embodiments, the sidewall of the horn mouth forms a groove at the position corresponding to the inner recess, the depth of the groove gradually increases from the waveguide to the port site.

[0013] In one of the embodiments, the bottom surface of the groove is arranged in the same plane with the sidewall of the corresponding side of the waveguide.

[0014] In one of the embodiments, the horn antenna has a height direction extending from the waveguide to the port site, and the total height H1 of the horn antenna is less than or equal to 5mm.

[0015] In one of the embodiments, the waveguide is straight and has a caliber size corresponding to a WR10 waveguide.

[0016] In one of the embodiments, the horn antenna is made of plastic material and the inner surface is plated with a metal coating.

[0017] In one of the embodiments, the plastic material part of the horn antenna is integrally injection molded.

[0018] The application also provides a vehicle-mounted millimeter wave radar comprising an antenna, which is the horn antenna described in the application.

[0019] The horn antenna structure of the application is simple and easy to process, and can realize the specific pattern required by the millimeter wave radar by relying on the horn mouth; the overall size is small, and compared with the millimeter wave radar antenna unit currently used, it has a smaller radiation aperture; the manufacturing cost is greatly reduced, because it can be processed using a single-layer board or a double-layer board, so that the processing cost is significantly reduced compared with three-layer or four-layer antennas, which is conducive to large-scale processing and manufacturing; compared with the traditional single-horn antenna, it has better radar pattern characteristics. BRIEF DESCRIPTION OF DRAWINGS

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

[0021] Figure 1 Fig. 1 is a perspective view of a horn antenna according to an embodiment of the present application;

[0022] Figure 2 Fig. 2 is a top view of the horn antenna according to an embodiment of the present application; Figure 1

[0023] Figure 3 Fig. 3 is a side view of the horn antenna according to an embodiment of the present application; Figure 1

[0024] Figure 4 Fig. 4 is a diagram showing the azimuth beam width of the horn antenna according to an embodiment of the present application;

[0025] Figure 5 Fig. 5 is a diagram showing the S11 index of the horn antenna according to an embodiment of the present application;

[0026] Figure 6 Fig. 6 is a diagram showing the comparison of the azimuth beam width between the horn antenna according to an embodiment of the present application and a conventional horn antenna;

[0027] Figure 7 Fig. 7 is a diagram showing the comparison of the elevation beam width between the horn antenna according to an embodiment of the present application and a conventional horn antenna.

[0028] The reference signs of the components are as follows:

[0029] 100, waveguide; 110, first side; 111, straight section; 120, second side;

[0030] 200, horn mouth; 210, long side; 211, inner recess; 220, short side. DETAILED DESCRIPTION

[0031] In order to make the above objectives, features and advantages of the present application more clear and easily understood, the 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 variety of ways beyond the specific embodiments described herein without departing from the scope of the present application, and it is understood that similar improvements can be made by those skilled in the art in light of the foregoing description. Therefore, the present application is not limited to the following disclosed specific embodiments.

[0032] 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 can be a middle component. When a component is referred to as being "connected to" another component, it can be directly connected to the other component or there can be a middle component. The terms "vertical", "horizontal", "upper", "lower", "left", "right", and similar expressions used in the description of the present application are for the purpose of illustration only and are not intended to be the only implementation. ​​

[0033] In addition, the terms "first", "second", etc. are used only for descriptive purposes and do not connote or imply relative importance or a quantity of the indicated technical features. Thus, a feature defined with "first", "second", etc. can include at least one of the feature explicitly or implicitly. In the description of the present application, the meaning of "a plurality" is at least two, for example, two, three, etc., unless otherwise explicitly and specifically limited.

[0034] In the present application, unless otherwise explicitly specified and limited, the "on", "under", "above" and "over" of the first feature to the second feature 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 "on", "above" and "over" of the first feature to the second feature 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 "under", "below" and "under" of the first feature to the second feature 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).

[0035] 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 skilled 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.

[0036] The 4D millimeter wave radar antenna unit in the prior art is in the form of a horn array, and has a large antenna volume, many layers of structure, and high manufacturing cost. 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.

[0037] Reference is made to Figures 1-3 An embodiment of the present application provides a horn antenna, comprising a waveguide tube 100 and a horn mouth 200 connected with the waveguide tube 100 and outwardly expanded in shape;

[0038] The horn mouth 200 is in transition connection with the waveguide tube 100 at one end, and the other end, i.e., the side away from the waveguide tube 100, is a port part. The outer contour shape of the port part is overall rectangular, and the edge includes two long sides 210 arranged oppositely and two short sides 220 connected between the two long sides 210. The long side 210 has a span L2, and the short side 220 has a span W2. Based on the improvement of the present application, the long side 210 is not strictly limited to a straight side, but has a concave part 211 offset towards each other in the middle region of the two long sides 210, i.e., the distance between the two long sides 210 is narrowed at the part where the concave part 211 is located.

[0039] The horn antenna of the embodiment can be processed on one plate, i.e., integrally injection molded, avoiding the cumbersome process of multiple molding and then splicing. Compared with the traditional horn antenna without the concave part 211, the horn antenna of the embodiment can obtain a wider azimuth beam width and a narrower elevation beam width through the concave structure of the two long sides 210, which is more suitable for the application scenario of automobile millimeter wave radar, and has a simple structure and is easy to process, with high processing robustness.

[0040] In one embodiment, the waveguide tube 100 is straight and has a size corresponding to a WR10 waveguide, for example, the outer contour shape of the waveguide tube 100 includes two first side edges 110 and two second side edges 120. The first side edge 110 extends substantially in the same direction as the long side 210, and the second side edge 120 extends substantially in the same direction as the short side 220. The intersection part of the first side edge 110 and the second side edge 120 can adopt a chamfered or rounded structure. The first side edge 110 includes at least a straight section 111 having a span L4. In the extension direction of the long side 210, the waveguide tube 100 has a span L1, and in the extension direction of the short side 220, the waveguide tube 100 has a span W1. When corresponding to the standard WR10 size, L1*W1 is 2.54mm*1.27mm, which can be more suitable for signal transmission of millimeter wave radar, and can well match the chip and test waveguide, having good versatility.

[0041] The horn antenna of the present application is a corner horn antenna, and the horn mouth 200 has an outward expansion tendency in the E plane and the H plane with respect to the waveguide tube 100. The long side 210 corresponds to the H plane, and the short side 220 corresponds to the E plane. Considering that the horn antenna is a typical aperture antenna, it can be regarded as a plurality of radiation elements working on the aperture surface. Changing the position of the elements can change the radiation mode of the horn antenna. Therefore, by reducing the proportion of the radiation size in the E plane, a wider azimuth beam width and a narrower elevation beam width can be obtained.

[0042] The size of the inner recess 211 affects the antenna performance to some extent. In an embodiment, the inner recess 211 has a span L3 along the extension direction of the long side 210, and the span L3 is one-half of the wavelength of the horn antenna. The inner recess 211 has a depth W3 along the extension direction of the short side 220, and the depth W3 is one-fourth of the wavelength of the horn antenna.

[0043] In terms of the configuration of the horn mouth 200 and the waveguide tube 100, the inner recesses 211 of the two long sides 210 are symmetrical to each other and are arranged at equal intervals in the extension direction of the long side 210. The side wall of the horn mouth 200 where the long side 210 is located forms a groove at a position corresponding to the inner recess 211. The bottom surface of the groove is arranged in the same plane as the side wall of the corresponding side of the waveguide tube 100. Due to the outward expansion of the shape of the horn mouth 200, the depth of the groove gradually deepens from the waveguide tube 100 to the port part until reaching the depth W3.

[0044] In order to obtain a simpler antenna structure and a smaller antenna size, in an embodiment, the horn antenna has a height direction extending from the waveguide tube 100 to the port part, the horn mouth 200 has a height H2, and the horn antenna has a total height H1. The total height H1 is generally less than or equal to 5 mm. This size setting is more in line with the mass production requirements of automotive millimeter wave radars. In a further preferred embodiment, the total height H1 is less than 4 mm to ensure the feasibility of injection molding. When the total height H1 is equal to 4 mm, an antenna gain of 10 dBi can be obtained, which can meet the use requirements.

[0045] In order to further reduce the cost, in an embodiment, the horn antenna is made of plastic material and has a metal coating on the inner surface. The use of a plastic surface coated with metal instead of traditional all-metal materials effectively reduces the cost and the weight of the product, and is more suitable for the application of vehicle-mounted millimeter wave radars. The plastic material part of the horn antenna is integrally injection molded, and its shape characteristics can be molded in a simple demolding manner, avoiding the complexity of multi-segment molding.

[0046] Based on the above embodiments, the application further provides a vehicle-mounted millimeter wave radar using the horn antenna of the above embodiments.

[0047] Referring to Figures 4-7 The horn antenna of the application has a very wide operating bandwidth and excellent radiation performance, Figure 5 The S11 index diagram of the horn antenna is shown in the figure, and the -15 dB bandwidth covers the working frequency band of 75-86 GHz of the millimeter wave automotive radar, which is 11 GHz.

[0048] Figure 6 and Figure 7It can be seen that the horn antenna (the performance curve in the figure is a dashed line) has wider azimuth beam width and narrower elevation beam width compared with the conventional horn antenna (the performance curve in the figure is a solid line).

[0049] The designed antenna structure achieves a gain of 11 dB in the working frequency band, an azimuth 5dB beam width of 140° (see Figure 4 the angle α in the figure), an elevation 5dB beam width of 35°, and a radiation pattern suitable for millimeter wave radar.

[0050] The optimized horn antenna covers the working frequency range of 76GHz to 81GHz of the automotive millimeter wave radar, has wider azimuth beam width and narrower elevation beam width, and has simple and compact structure. It can be directly produced on a substrate, is easy to manufacture, significantly reduces the antenna processing cost, and is suitable for large-scale mass production of automotive millimeter wave radar.

[0051] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, but as long as the combinations of the technical features do not contradict, they should be considered within the scope of the present disclosure. When the technical features in different embodiments are embodied in the same figure, it can be considered that the figure also discloses the combination of the embodiments involved.

[0052] The above-described embodiments only express several implementation manners of the present application, and the description is specific and detailed, but it should not be understood as a limitation on the patent scope of the application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. A horn antenna, characterized in that: It includes a waveguide tube and a bell mouth connected to the waveguide tube and having an outward-expanding shape; The side of the horn away from the waveguide tube is a port portion, and the edge of the port portion includes two long sides arranged opposite to each other and two short sides connected between the two long sides, wherein the middle areas of the two long sides have inner recesses offset towards each other.

2. The horn antenna according to claim 1, wherein: Along the extending direction of the long side, the inner concave portion has a span L3, and the span L3 is half the wavelength of the horn antenna.

3. The horn antenna according to claim 1, wherein: Along the extending direction of the short side, the inner concave portion has a depth W3 , and the depth W3 is a quarter of the wavelength of the horn antenna.

4. The horn antenna according to claim 1, wherein: The inner concave portions of the two long sides are symmetrical to each other and are arranged at equal intervals in the extending direction of the long sides.

5. The horn antenna according to claim 1, wherein: The horn antenna is a pyramidal horn antenna, 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.

6. The horn antenna according to claim 5, characterized in that A groove is formed on the side wall of the bell mouth at a position corresponding to the inner recess, and the depth of the groove gradually increases from the waveguide to the port.

7. The horn antenna according to claim 6, characterized in that The bottom surface of the groove is coplanar with the side wall of the corresponding side of the waveguide.

8. The horn antenna according to claim 1, wherein: The horn antenna has a height direction extending from the waveguide tube to the port portion, and the total height H1 of the horn antenna is less than or equal to 5 mm; the waveguide tube is straight cylindrical, and the diameter size corresponds to that of the WR10 waveguide.

9. The horn antenna according to claim 1, wherein: The horn antenna is made of plastic material and the inner surface is plated with a metal coating; the plastic material part of the horn antenna is integrally injection-molded.

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

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