Radar sensor with decoupling means for surface waves

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 surroundings (16) of the radar sensor (10), comprising a main part (18), an antenna surface (20) on the main part (18), said antenna surface facing the sensor surroundings (16) and having an electrically conductive surface material (22), a first antenna element (24) in the form of at least one opening (26) in the antenna surface (20), and a second antenna element (34) in the form at least one additional opening (36) in the antenna surface (20), wherein the waveguide antenna (12) has decoupling means (38) at least between the first and second antenna element (24, 34), said decoupling means being designed to change at least the transmission of surface waves (40), in the form of radar waves (14) which travel on the surface, between the first and second antenna element (24, 34).

Description

[0001] Radar sensor with decoupling agents for surface waves

[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. This improves the radiation characteristics of the radar sensor.

[0006] Disclosure of the invention

[0007] According to the present invention, a radar sensor with the features of claim 1 is proposed. This allows crosstalk between the antenna elements to be reduced. The antenna elements can be more effectively decoupled from each other. 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. The waveguide antenna can be a receiving antenna and / or a transmitting antenna for radar waves.

[0011] The first and second antenna elements are each components of the waveguide antenna that transmit electromagnetic energy between the radar sensor and the sensor environment. The first and / or second antenna element can be designed as a slot.

[0012] In the base body, several waveguides transmitting the radar waves can be designed as waveguides. The base body can be arranged on a circuit board. The first and / or second antenna element can be connected to at least one of the waveguides for transmitting the radar waves. The base body can be formed from a base body material. The base body can be produced by injection molding and / or 3D printing. The base body can be at least partially, in particular completely, preferably coated with the surface material. The base body can be constructed from a plastic, in particular a thermoplastic or duroplastic. The plastic can be filled with carbon.

[0013] The radar sensor can be protected by a protective component against environmental influences from the sensor's surroundings, in particular dirt, moisture, and / or water. 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 be constructed of plastic and / or a composite material to allow the radar waves to pass through.

[0014] 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.

[0015] The surface material can be a metal or a metal alloy.

[0016] The surface waves are the radar waves that propagate within and / or along the physical structures, for example the base body, of the radar sensor mainly and / or at least in an initial transmission path from the generation of the surface waves superficially, for example with respect to the base body and / or the antenna surface.

[0017] The decoupling means are introduced in addition to the antenna elements and are to be distinguished from the antenna means. The decoupling means can be arranged at least in sections in a direct connection between the first and second antenna elements. The decoupling means can be arranged centrally or off-center with respect to the extension of the connection. The decoupling means can be arranged over the majority of the length of the connection. The decoupling means can be adapted in at least one dimension, in particular in several, preferably in all dimensions, for example the length, width, depth, or height, to adjust the impedance of the decoupling means and / or the phase change and / or the amplitude change of the surface waves.

[0018] The adaptation of the first antenna element can be adapted to the adaptation of the second antenna element by suitable arrangement and / or dimensioning of the decoupling means, or it can be specifically set to deviate from the adaptation of the second antenna element. The adaptation of the first antenna element can be a transmission coefficient, a reflection coefficient, and / or a return loss, in particular a frequency-dependent one, of the respective antenna element. The adaptation can comprise a target frequency range in which at least one of the aforementioned parameters is set below a threshold value. The decoupling means can effect a target frequency range for the first antenna element that is aligned with a target frequency range of the second antenna element or is offset from a target frequency range of the second antenna element.If the target frequency ranges are offset, the bandwidth of the radar sensor can be increased.

[0019] The waveguide antenna can have a third antenna element designed as at least one further opening in the antenna surface. In addition to the decoupling means arranged between the first and second antenna elements, the waveguide antenna can have second decoupling means structured as a first decoupling means between the second and third antenna elements or between the first and third antenna elements, which are configured to change the transmission of surface waves, which occur as surface-propagating radar waves in the waveguide antenna, between the second and third antenna elements or the first and third antenna elements. The first and second decoupling means can be designed and / or arranged such that the remaining transmission of the surface waves via the first decoupling means is matched to the remaining transmission of the surface waves via the second decoupling means.This allows the transmission of surface waves to be homogenized overall.

[0020] In an advantageous embodiment of the invention, the decoupling means inhibit, in particular block, the transmission of surface waves. The transmission of surface waves can be inhibited by scattering, reflection, and / or absorption of the surface waves.

[0021] In a specific embodiment of the invention, it is advantageous if the decoupling means are designed as decoupling means structured on the antenna surface. This allows the transmission of the surface waves between the first and second antenna elements to be directly modified. The surface waves can be at least partially deflected into the base body by the decoupling means.

[0022] In a preferred embodiment of the invention, it is advantageous if the decoupling means comprise at least one partial volume in the base body, a recess and / or a depression in the antenna surface, and / or an elevation relative to the antenna surface. The recess, the depression, and / or the elevation can comprise at least one beveled side wall.

[0023] In an advantageous embodiment of the invention, it is provided that the partial volume, the recess, the depression, and / or the elevation comprises a filler material and / or, with respect to the sensor environment, a surface material that differs from the surface material. An electrical conductivity of the surface material can be greater than the electrical conductivity of the filler material and / or the surface material. A complex permittivity and / or a complex permeability of the surface material can be greater or less than that of the filler material and / or the surface material. The surface material can correspond to the filler material or differ from the filler material.

[0024] In a preferred embodiment of the invention, the surface material and / or the filler material differs from the base material of the base body. The filler material and / or the surface material can be a thermoplastic or thermoset. At least one base surface, one side wall, preferably all side walls, of the partial volume, the recess, the depression, and / or the elevation can comprise the surface material, the base material, the surface material, and / or the filler material.

[0025] In an advantageous embodiment of the invention, the decoupling means are provided within the base body. The decoupling means can be recesses that are at least partially, in particular completely, enclosed by the base body. The recesses can be open or closed to the sensor environment. The decoupling means can be partially or completely filled with the filler material.

[0026] In a preferred embodiment of the invention, the decoupling means are configured to scatter the surface waves into the sensor environment, to reflect the surface waves, and / or to absorb them. This can inhibit the transmission of the surface waves between the first and second antenna elements. The surface waves of the first antenna element can also be specifically scattered by the decoupling means in front of the second antenna element or in the region of the second antenna element, for example, to change the matching of the second antenna element. The surface waves of the second antenna element can be specifically scattered by the decoupling means in front of the first antenna element or in the region of the first antenna element, for example, to change the matching of the first antenna element.The decoupling agents can also change the surface waves themselves, for example the amplitude, phase and / or frequency of the surface waves.

[0027] In an advantageous embodiment of the invention, the waveguide antenna comprises absorber means for absorbing surface waves. This allows the surface waves to be attenuated. The absorber means may comprise, at least in sections, an absorber material that differs from the surface material. The absorber means may be formed by at least one material that absorbs radar waves, in particular with a loss factor describing the dielectric losses greater than 0.01, in particular greater than 0.1. The absorber material may correspond to the filler material and / or the base material, or it may differ from the filler material and / or the base material.

[0028] In a specific embodiment of the invention, it is advantageous if the absorber means are formed at least partially by the base body. This allows the radar sensor to be designed cost-effectively and in a space-saving manner. The absorber means can be formed predominantly by the base body. The decoupling means can comprise multiple absorber means.

[0029] Further advantages and advantageous embodiments of the invention emerge from the description of the figures and the illustrations.

[0030] Character description

[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 an electrically conductive surface material 22 at least in sections.

[0036] Furthermore, the waveguide antenna 12 comprises at least a first 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 first 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 base body 18 and the antenna surface 20 on the base body 18, which has the electrically conductive surface material 22. The surface material 22 can be a metal or a metal alloy and is applied to the base body 18 as a surface layer.

[0038] The first antenna element 24 is designed as an opening 26 in the antenna surface 20. The waveguide antenna 12 further comprises a second antenna element 34, spaced apart from the first antenna element 24, which is designed as a further opening 36 in the antenna surface 20.

[0039] The waveguide antenna 12 comprises structured decoupling means 38 configured to modify the transmission of surface waves 40 as surface-propagating radar waves between the first and second antenna elements 24, 34. The surface waves 40 can originate from the first and second antenna elements 24, 34, respectively. The decoupling means 38 are structured on the antenna surface 20 and comprise a recess 42 in the antenna surface 20 between the first and second antenna elements 24, 34, at least one further recess 44 in the antenna surface 20 adjacent to the first antenna element 24, and at least one further recess 46 in the antenna surface 20 adjacent to the second antenna element 34. The recesses 42, 44, 46 interrupt, in particular, the surface material 22.

[0040] The recess 42 borders on a partial volume 48 in the base body 18, which is provided with a

[0041] Filling material 50, which is separated from the surface material 22 and in particular from the

[0042] The partial volume 48 extends a depth 52 into the base body 18 and, with respect to the sensor environment 16, has a surface material 53 corresponding to the filling material 50.

[0043] The further recess 44 next to the first antenna element 24 has a partial volume 54 with the filler material 50. The further recess 44 is larger than the recess 42 with respect to the antenna surface 20, and the partial volume 54 extends at least partially below the antenna surface 20 in the base body 18. The further recess 46 next to the second antenna element 34 also has a partial volume 56 with the filler material 50. The further recess 46 is larger than the recess 42 with respect to the antenna surface 20, and the partial volume 56 extends at least partially below the antenna surface 20 in the base body 18.

[0044] The radar waves 14 from the first antenna element 24 are emitted into the sensor environment 16. The surface waves 40 are generated as surface-propagating radar waves emanating from the first antenna element 24. The transmission of the surface waves 40 to the second antenna element 34 is inhibited by the decoupling means 38 in that the surface waves 40 are scattered at the partial volume 48, for example, into the sensor environment 16. The surface waves 40 emitted by the first antenna element 24 in the direction opposite to the second antenna element 34 are scattered by the partial volume 54 into the sensor environment 16. Furthermore, the base body 18 can, at least in some regions, represent absorber means 58 for the surface waves 40, which at least partially absorb the surface waves 40. The partial volume 54 can also be at least partially filled to form the absorber means 58.

[0045] The surface waves 40 emanating from the second antenna element 34 in the direction of the first antenna element 24 are also prevented from further transmission to the first antenna element 24 by the partial volume 48 and, for example, scattered into the sensor environment 16. This can reduce crosstalk caused by the surface waves 40 between the first and second antenna elements 24, 34.

[0046] The surface waves 40 emitted by the second antenna element 34 in the direction opposite to the first antenna element 24 are prevented from further transmission by the partial volume 56 and scattered into the sensor environment 16. Furthermore, the partial volume 56 can represent, at least in some regions, absorbing means 58 for the surface waves 40, which at least partially absorb the surface waves 40.

[0047] Figure 3 shows a cross-section of a radar sensor in another specific embodiment of the invention. The decoupling means 38 are designed as depressions 60 in the antenna surface 20. The surface material 22 is also arranged in the depressions 60. The depression 60 is set back by a depth 52 from the antenna surface 20. A base area 61 and the side walls 62 of the respective depression 60 are covered with the surface material 22. The side walls 62 are beveled to scatter the surface waves 40 into the sensor environment 16.

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) of the radar sensor (10), with a base body (18), an antenna surface (20) facing the sensor environment (16) and comprising an electrically conductive surface material (22) on the base body (18), a first antenna element (24) designed as at least one opening (26) in the antenna surface (20), and a second antenna element (34) designed as at least one further opening (36) in the antenna surface (20), characterized in that the waveguide antenna (12) has decoupling means (38) at least between the first and second antenna elements (24, 34), which are designed to at least the transmission of surface waves (40) as surface-running radar waves (14) between the first and second to change the antenna element (24, 34).

2. Radar sensor (10) according to claim 1, characterized in that the decoupling means (38) inhibit the transmission of the surface waves (40).

3. Radar sensor (10) according to claim 1 or 2, characterized in that the decoupling means (38) are designed as decoupling means (38) structured on the antenna surface (20).

4. Radar sensor (10) according to one of the preceding claims, characterized in that the decoupling means (38) have at least one partial volume (48, 54, 56) in the base body (18), a recess (42) and / or a depression (60) in the antenna surface (20) and / or an elevation relative to the antenna surface (20).

5. Radar sensor (10) according to claim 4, characterized in that the partial volume (48, 54, 56), the recess (42), the depression (60) and / or the elevation comprises a filling material (50) and / or, with respect to the sensor environment (16), a surface material (53) which differs from the surface material (22).

6. Radar sensor (10) according to claim 5, characterized in that the surface material (53) and / or the filling material (50) differs from the base body material of the base body (18).

7. Radar sensor (10) according to one of the preceding claims, characterized in that the decoupling means (38) are designed within the base body (18).

8. Radar sensor (10) according to one of the preceding claims, characterized in that the decoupling means (38) are arranged to scatter the surface waves (40) into the sensor environment (16), to reflect and / or to absorb the surface waves (40).

9. Radar sensor (10) according to one of the preceding claims, characterized in that the waveguide antenna (12) has absorber means (58) for absorbing the surface waves (40).

10. Radar sensor (10) according to claim 9, characterized in that the absorber means (58) are formed at least in regions by the base body (18).

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