Radar sensor having reflection-inhibiting means

Abstract

The invention relates to a radar sensor (10), having a waveguide antenna (12) for emitting and / or receiving radar waves (14) with respect to the sensor surroundings (16), an antenna surface (20) which faces the sensor surroundings (16) and has an electrically conductive surface material (22) at least in some parts, and at least one antenna element (24) which is in the form of at least one opening (26) in the antenna surface (20) and which lies opposite a protective component (34) located in the sensor surroundings (16). The antenna surface (20) has structured reflection-inhibiting means (36) which are designed to inhibit the reflection of scattered waves (38), in the form of radar waves (14) reflected by the protective component (34), between the protective component (34) and the antenna surface (20) at least by interfering with the scattered waves (38).

Description

[0001] Radar sensor with reflection inhibitors

[0002] The invention relates to a radar sensor according to the preamble of claim 1.

[0003] State of the art

[0004] DE 102022 202 140 A1 describes a radar sensor with an injection-molded waveguide antenna.

[0005] DE 102018218253 A1 describes a radar sensor comprising an antenna structure and a coupling structure for the targeted coupling of surface waves from the antenna structure. The coupled surface waves are absorbed by an absorber in the radome.

[0006] Disclosure of the invention

[0007] According to the present invention, a radar sensor with the features of claim 1 is proposed. This reduces disruptive reflections between the protective component and the waveguide antenna. The radar sensor can be operated more reliably and designed more cost-effectively. The measurement accuracy of the radar sensor can be increased.

[0008] The radar sensor can be arranged in a vehicle, in particular a motor vehicle, truck, and / or two-wheeled vehicle. The radar sensor can be arranged in a mobile robot.

[0009] The radar waves can be electromagnetic waves in the millimeter band.

[0010] The waveguide antenna can be constructed from several components. The components can be made of different materials.

[0011] The waveguide antenna can have multiple antenna elements. The antenna element is a component of the waveguide antenna that transmits electromagnetic energy between the radar sensor and the sensor environment. The antenna element can be designed as a slot. The waveguide antenna can be a receiving antenna and / or a transmitting antenna for the radar waves. The protective component can be a radome, a housing, and / or a trim component, in particular a bumper or body component of the vehicle. The protective component can protect the radar sensor from environmental influences, in particular dirt, moisture, and / or water. The protective component can be constructed of plastic and / or a composite material to allow the radar waves to pass through.

[0012] The structured reflection inhibiting means comprise structural structures on, at and / or in the antenna surface which have a reflective effect on scattered waves incident from the protective component.

[0013] The antenna surface can form, at least in part, a sensor surface of the radar sensor. The protective component can also form a sensor surface.

[0014] In a preferred embodiment of the invention, it is advantageous if the reflection-inhibiting means comprise at least one first reflection surface and at least one adjacent second reflection surface offset from the first reflection surface by a height difference. This allows reflection centers of the scattered waves to be relocated to different heights, resulting in wave interference of the scattered waves and, due to the phase shift resulting from the height difference, in a reduction of the resulting scattered waves.

[0015] The height difference and / or the dimensions of the first and / or second reflection surface in at least one dimension or in both dimensions can be adjusted such that the scattered waves reflected at different heights reduce, preferably cancel, each other out for a given reflection angle or reflection angle range and / or a given frequency range of the scattered waves. The height difference and / or at least one dimension of the first and / or second reflection surface are adapted to the wavelength in at least one dimension or in both dimensions.

[0016] Furthermore, the first and second reflection surfaces arranged at different heights can cause the scattered waves to be scattered over a larger angular range and thus spatially distribute the reflected wave energy.

[0017] The first and / or second reflection surface may be square or preferably deviate from a square shape.

[0018] The first and / or second reflection surface can form the antenna surface in the region of the reflection-inhibiting means. In a preferred embodiment of the invention, the second reflection surface is formed in a recess open to the sensor environment. The first reflection surface can be arranged on a raised portion protruding from the antenna surface.

[0019] A preferred embodiment of the invention is advantageous in which a transition between the first and second reflection surfaces is rounded and / or beveled. This allows the reflection inhibition means to be manufactured more easily, for example, by injection molding. Furthermore, the frequency dependence and / or angle dependence of the reflection inhibition can be reduced.

[0020] In a specific embodiment of the invention, it is advantageous if the waveguide antenna has a base body in which several waveguides transmitting the radar waves are implemented, and the second reflection surface is arranged on a side of the base body facing away from the first reflection surface. The second reflection surface can be a rear surface material on the base body. The rear surface material can be a different material from the base body and the surface material of the antenna surface. The radar waves can penetrate the base body on a side of the base body opposite the second reflection surface and be reflected by the second reflection surface toward the sensor environment.

[0021] The waveguide antenna can have a base body in which several waveguides transmitting the radar waves are implemented. The base body can be arranged on a circuit board. The antenna element can be connected to at least one of the waveguides for transmitting the radar waves. The base body can be manufactured by injection molding and / or 3D printing. The base body can be at least partially, in particular completely, coated with the surface layer of the antenna surface. The base body can be constructed from a plastic, in particular a thermoplastic or thermoset, which can additionally be mixed with an absorbent.

[0022] The surface material of the antenna surface can be a coating of the base body.

[0023] In a preferred embodiment of the invention, the surface material of the first and second reflection surfaces is the same. The first and second reflection surfaces can have the same surface material as the antenna surface. The first and second reflection surfaces can be made of metal or a metal alloy. The first and / or second reflection surfaces can have a single, uniform surface material. The surface material is a solid.

[0024] In a specific embodiment of the invention, it is advantageous if a surface material of the first and / or second reflection surface differs at least in sections from the surface material of the antenna surface. The material of the base body can form the surface material of the second reflection surface.

[0025] The reflection-inhibiting means may comprise a first surface material on the first reflection surface and a second surface material on the second reflection surface. The first and second surface materials may be the same or different from each other. The first and / or second surface materials may correspond to the material of the base body or differ from the material of the base body.

[0026] The first reflection surface can be designed to absorb and / or reflect at least a first frequency of the scattered waves, and the second reflection surface can be designed to absorb and / or reflect at least a second frequency of the scattered waves. The first and second frequencies can be the same or different from each other.

[0027] In a specific embodiment of the invention, it is advantageous if the electrical conductivity of a surface material of the first and / or second reflection surface is lower than the electrical conductivity of the surface material of the antenna surface. This allows the scattered waves to penetrate into the surface material of the second reflection surface, in particular into the base body, and be absorbed.

[0028] In an advantageous embodiment of the invention, the complex permittivity and / or complex permeability of a surface material of the first and / or second reflection surface is different from that of the respective surface material of the antenna surface. This allows the scattered waves to be absorbed by the reflection-inhibiting means.

[0029] In a preferred embodiment of the invention, a surface material of the first and / or second reflection surface has a relative permittivity that is closer to air than the surface material of the antenna surface. This can increase the absorption of scattered waves by the reflection-inhibiting means.

[0030] Further advantages and advantageous embodiments of the invention will become apparent from the description of the figures and the illustrations.

[0031] The invention is described in detail below with reference to the figures. They show in detail:

[0032] Figure 1: A cross-section of a radar sensor in a specific embodiment of the invention.

[0033] Figure 2: A cross-section of a radar sensor in another specific embodiment of the invention.

[0034] Figure 3: A cross-section of a radar sensor in another specific embodiment of the invention.

[0035] Figure 1 shows a cross-section of a radar sensor in a specific embodiment of the invention. The radar sensor 10 comprises a waveguide antenna 12 for transmitting and / or receiving radar waves 14 with respect to a sensor environment 16 of the radar sensor 10. The radar sensor 10 can be arranged in a vehicle. The waveguide antenna 12 comprises a base body 18 and an antenna surface 20 on the base body 18 facing the sensor environment 16, which surface 20 has, at least in sections, an electrically conductive first surface material 22.

[0036] Furthermore, the waveguide antenna 12 comprises at least one antenna element 24, which is designed as an opening 26 in the antenna surface 20. The radar waves 14 are generated and / or processed by a sensor chip 28. The sensor chip 28 is connected to the antenna element 24 via waveguide channels 30, which are designed at least in sections as waveguides, for transmitting the radar waves 14. The sensor chip 28 is arranged on a circuit board 32, which is accommodated in the base body 18.

[0037] Figure 2 shows a cross-section of a radar sensor in another specific embodiment of the invention. The radar sensor 10 comprises the waveguide antenna 12 with the antenna surface 20, which faces the sensor environment 16 and has, at least in sections, an electrically conductive surface material 22. The surface material 22 can be a metal or a metal alloy and is applied as a surface layer to the base body 18, which is made of plastic, for example. Furthermore, the waveguide antenna 12 comprises the antenna element 24, which is designed as an opening 26 in the antenna surface 20 and which is opposite a protective component 34 arranged in the sensor environment 16. The protective component 34 can be a radome or a bumper of the vehicle.

[0038] The antenna surface 20 comprises structured reflection-inhibiting means 36 for reducing the radar waves 14 reflected as scattered waves 38 between the protective component 34 and the antenna surface 20 by wave interference 39 of the scattered waves 38. The reflection-inhibiting means 36 comprise a plurality of first reflection surfaces 40 and a plurality of second reflection surfaces 44, each adjacent to the first reflection surfaces 40 and set back from the first reflection surfaces 40 by a height difference 42. The second reflection surfaces 44 are each formed in a recess 46 open relative to the sensor environment 16. A transition 48 between the first and second reflection surfaces 40, 44 is preferably rounded and beveled. The side walls 50 of the recess 46 are beveled relative to the antenna surface 20 at an inclination angle 52 different from 90°.This allows the reflection inhibition means 36 to be manufactured more easily, for example, by injection molding. Furthermore, the frequency dependence and / or angle dependence of the reflection inhibition can be reduced.

[0039] A surface material 56 of the first and second reflection surfaces 40, 44 is identical and is formed by the electrically conductive surface material 22 of the antenna surface 20. The first and second reflection surfaces 40, 44 form the antenna surface 20 in the region of the reflection-inhibiting means 36.

[0040] Figure 3 shows a cross-section of a radar sensor in another specific embodiment of the invention. The radar sensor 10 comprises the reflection-inhibiting means 36 with the first reflection surfaces 40 and the second reflection surfaces 44, which are set back from the first reflection surfaces 40 and have absorption means 54 for dampening the scattered waves 38. The surface material 56 of the second reflection surfaces 44 is different from the surface material 56 of the first reflection surfaces 40. The surface material 56 of the second reflection surfaces 44 is preferably formed by the material of the base body 18, for example, plastic. The surface material 56 of the first reflection surfaces 40 is preferably formed by the surface material 22 of the antenna surface 20.

[0041] The electrical conductivity of the surface material 56 of the second reflection surfaces 44 is in particular smaller than the electrical conductivity of the surface material 22 of the antenna surface 20. Furthermore, the complex permittivity and / or complex permeability of the surface material 56 of the second reflection surfaces 44 is different from that of the respective surface material 22 of the antenna surface 20, and the surface material 56 of the second reflection surfaces 44 has a relative permittivity that is more similar to air than the surface material 22 of the antenna surface 20.

Claims

Patent claims 1. Radar sensor (10), comprising a waveguide antenna (12) for transmitting and / or receiving radar waves (14) with respect to a sensor environment (16), with an antenna surface (20) facing the sensor environment (16) and at least partially comprising an electrically conductive surface material (22), and at least one antenna element (24) which is designed as at least one opening (26) in the antenna surface (20) and which lies opposite a protective component (34) arranged in the sensor environment (16), characterized in that the antenna surface (20) has structured reflection inhibiting means (36) which are configured to inhibit the reflection of scattered waves (38) as radar waves (14) reflected by the protective component (34) between the protective component (34) and the antenna surface (20) at least by wave interference (39) of the scattered waves (38).

2. Radar sensor (10) according to claim 1, characterized in that the reflection inhibiting means (36) have at least one first reflection surface (40) and at least one adjacent second reflection surface (44) offset from the first reflection surface (40) by a height difference (42).

3. Radar sensor (10) according to claim 2, characterized in that the second reflection surface (44) is designed in a recess (46) open with respect to the sensor environment (16).

4. Radar sensor (10) according to claim 2 or 3, characterized in that a transition (48) between the first and second reflection surfaces (40, 44) is rounded and / or bevelled.

5. Radar sensor (10) according to one of claims 2 to 4, characterized in that the waveguide antenna (12) has a base body (18) in which a plurality of waveguides (30) transmitting the radar waves (14) are designed and the second reflection surface (44) is arranged on a side of the base body (18) facing away from the first reflection surface (40).

6. Radar sensor (10) according to one of claims 2 to 5, characterized in that a surface material (56) of the first and second reflection surfaces (40, 44) is the same.

7. Radar sensor (10) according to one of claims 2 to 6, characterized in that a surface material (56) of the first and / or second reflection surface (40, 44) deviates at least in sections from the surface material (22) of the antenna surface (20).

8. Radar sensor (10) according to one of claims 2 to 7, characterized in that the electrical conductivity of a surface material (56) of the first and / or second reflection surface (40, 44) is smaller than the electrical conductivity of the surface material (22) of the antenna surface (20).

9. Radar sensor (10) according to one of claims 2 to 8, characterized in that the complex permittivity and / or complex permeability of a surface material (56) of the first and / or second reflection surface (40, 44) is different from that of the respective surface material (22) of the antenna surface (20).

10. Radar sensor (10) according to one of claims 2 to 9, characterized in that a surface material (56) of the first and / or second reflection surface (40, 44) has a relative permittivity that is more similar to air than the surface material (22) of the antenna surface (20).

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