Radar sensor with emitting means for a secondary radiation

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), comprising a main part (18), an antenna surface (20) on the main part (18), said antenna surface facing the sensor surroundings (16) and having a surface material (22), and a first antenna element (24), in the form of at least one opening (26) in the antenna surface (20), for emitting the radar waves (14), as a useful radiation (34), directly into the sensor surroundings (16), wherein the waveguide antenna (12) has emitting means (38) designed to controlledly emit radar waves (14) that travel on the surface and form surface waves (36) as a secondary radiation (40), which contributes to the useful radiation (34), for adapting the radiation pattern of the first antenna element (24), said radiation pattern characterizing the useful radiation (34).

Description

[0001] Radar sensor with radiating agent for secondary radiation

[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 radiated onto an absorber and absorbed in a directional characteristic different from the directional characteristic of the antenna structure.

[0006] Disclosure of the invention

[0007] According to the present invention, a radar sensor with the features of claim 1 is proposed. This allows the antenna pattern of the radar sensor to be improved. The antenna pattern can be adjusted cost-effectively and in a space-saving manner. The surface waves can be guided in a controlled manner and / or radiated in a targeted manner to contribute to the useful radiation. 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 antenna element is a component of the waveguide antenna that transmits electromagnetic energy between the waveguide antenna and the sensor environment. The first antenna element can be designed as a slot, a circular opening, or an oval opening.

[0012] In contrast to parasitic radiation, useful radiation is the effective and usable radiation for operating the radar sensor, for example, for object detection. The useful radiation can be the radiation primarily characterized by at least one main lobe in the antenna pattern. Secondary radiation is deliberately added to the useful radiation and can contribute to the radar sensor's function associated with the useful radiation, for example, object detection.

[0013] The waveguide antenna may have at least one further second antenna element, which is designed as at least one opening in the antenna surface. The first and second antenna elements or further antenna elements may each have an antenna pattern.

[0014] 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 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 primarily coated with the surface material. The base body can be constructed of a plastic, in particular a thermoplastic or thermoset. The plastic can be filled with carbon.

[0015] Surface waves are present, in particular, outside the waveguides. Surface waves are radar waves that propagate within and / or along the physical structures, for example, the base body of the radar sensor, primarily and / or at least in an initial transmission path, superficially from the moment the surface waves are generated, for example, relative to the base body and / or the antenna surface.

[0016] 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.

[0017] 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 of the radar sensor. Adapting the antenna pattern can consist of setting a main lobe width of a main lobe, a main lobe direction of a main lobe, a side lobe direction of at least one side lobe, and / or a side lobe level of at least one side lobe of the radar wave radiation. A main lobe width, a main lobe direction, a side lobe direction, and / or a side lobe level can deviate due to the radiation means compared to the corresponding parameters without the radiation means. The secondary radiation can change the direction and / or intensity of the useful radiation.

[0018] The antenna pattern of the first antenna element can be adapted, in particular aligned, to the antenna pattern of the second antenna element by the radiation means. Mutual influences between the first and second antenna elements, for example, due to manufacturing defects, asymmetrical installation, housing influences, and the like, can be aligned by the radiation means.

[0019] The radiating means are exclusively structures present in addition to the first antenna element and / or other antenna elements and producing at most secondary radiation. The first antenna element and any additional antenna elements, which are primarily configured for the useful radiation, are distinct from the radiating means. A direct connection of the radiating means to the waveguides can be omitted. The radiating means can be arranged at a distance from the first antenna element. The radiation source of the secondary radiation of the radiating means can be spaced from the radiation source of the useful radiation of the first antenna element.

[0020] The emitting means can be configured to adjust the phase and / or amplitude of the radar waves emitted by the secondary radiation. A transmission path of the surface waves to the emitting means can be sufficiently long and / or comprise a damping material to reduce the amplitude of the surface waves entering the emitting means. By using a damping material, the amplitude can be adjusted independently of the phase, for example, to set specific phase-amplitude ratios.

[0021] The radiation means can have at least one first radiation element causing the secondary radiation. The radiation means can have a second radiation element causing further secondary radiation. The adaptation of the antenna pattern by the radiation means can depend on at least one dimension of the first and / or second radiation element and / or a distance between the first and second radiation elements. In a preferred embodiment of the invention, it is advantageous if the radiation means are designed as radiation means structured at least on the antenna surface. The radiation means can also be designed in the antenna surface and / or the base body. A depth of the structured radiation means can be in the range of less than 0.21, in particular less than 0.2, times the wavelength of the surface waves.

[0022] This allows the antenna pattern to be broadened. At greater depths, the antenna pattern can be narrower, as the radiating elements radiate surface waves more strongly.

[0023] In a preferred embodiment of the invention, it is advantageous if the radiating means comprise at least one recess and / or depression in the antenna surface and / or an elevation above the antenna surface. This allows the propagation of surface waves within the waveguide antenna to be influenced. The radiating means can compensate for the influence of defects, unevenness, and / or roughness in the antenna surface on the antenna pattern.

[0024] The first and second antenna elements can be arranged more compactly. The distance between the first and second antenna elements can be reduced.

[0025] The surface waves can be modified in phase and / or amplitude within the body. Within the body, the surface waves can be guided into a waveguide and emitted with a phase shift and / or a modified amplitude.

[0026] The shape of the radiating elements can be adjusted so that only specific areas of the antenna pattern receive additional energy from the secondary radiation. This can be achieved via three-dimensional structures on the base body and / or the antenna surface.

[0027] In a preferred embodiment of the invention, it is advantageous if the radiating means occupy a partial volume in the base body that has a filler material that is different from the surface material and / or a base body material of the base body. The filler material can correspond to the material of the sensor environment, in particular air. The filler material can also be a solid, in particular a plastic, preferably a thermoplastic or thermoset. The plastic can be filled with carbon.

[0028] In a specific embodiment of the invention, it is advantageous if the partial volume is arranged at least partially beneath the surface material of the antenna surface. The surface waves can be reflected, at least within the partial volume, by a rear side of the surface material facing away from the sensor environment, for example, to form a transmission path for the surface waves in the partial volume. The partial volume can also be dispensed with, and the surface waves can be reflected within the base body by a rear side of the surface material applied to the base body facing away from the sensor environment, for example, to form a transmission path for the surface waves in the base body.

[0029] In a specific embodiment of the invention, it is advantageous if the radiating means are configured to radiate the surface waves emanating from the first antenna element into the sensor environment. The radiating means can be arranged in the vicinity of the first antenna element. The radiating means can also be configured to radiate the surface waves emanating from the second antenna element. The surface waves emanating from the radiating means can also originate from reflected radar waves arriving at the antenna surface and transmitted into the waveguide antenna.

[0030] The radiating means can have surface structures on the antenna surface that have a depth such that, for example, less than 0.21 times the wavelength of the surface waves, preferably less than 0.2 times, that the surface waves are bound to the antenna surface and / or the base body or are radiated to a lesser extent than with greater surface structures. This can broaden the antenna pattern. A combination of smaller and larger depths can also be implemented, for example, to achieve an asymmetrical influence on the antenna pattern.

[0031] In a preferred embodiment of the invention, it is advantageous if the radiation means are configured to emit the secondary radiation at a first radiation position and at a second radiation position offset from the first radiation position relative to the antenna surface. This allows for a targeted superposition of the radar waves from the first radiation position with the radar waves from the second radiation position. Furthermore, the number of radiation positions of the radiation means and / or a distance between the radiation positions can be suitably adjusted to adapt the antenna pattern.

[0032] In a preferred embodiment of the invention, the radiation means comprise at least one radiation element arranged at an angle relative to the antenna surface. The angle of incidence relative to the antenna surface can be less than 90°. A preferred embodiment of the invention is advantageous in which the radiation element comprises an electrically conductive surface material at least on a surface facing the base body. The radiation element can be configured to reflect the surface waves from the surface material for radiation into the sensor environment. The angle of incidence can specify the radiation angle of the emitted surface waves depending on an angle of incidence of the surface waves onto the radiation element.

[0033] In a specific embodiment of the invention, it is advantageous if the first surface material is electrically conductive. The surface material can be a metal or a metal alloy.

[0034] Further advantages and advantageous embodiments of the invention emerge from the description of the figures and the illustrations.

[0035] Character description

[0036] The invention is described in detail below with reference to the figures. They show in detail:

[0037] Figure 1: A cross-section of a radar sensor in a specific embodiment of the invention.

[0038] Figure 2: A cross-section of a radar sensor in a specific embodiment of the invention.

[0039] Figure 3: A cross-section of a radar sensor in another specific embodiment of the invention.

[0040] Figure 4: A cross-section of a radar sensor in another specific embodiment of the invention.

[0041] Figure 5: A cross-section of a radar sensor in another specific embodiment of the invention.

[0042] 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.

[0043] Furthermore, the waveguide antenna 12 comprises at least a first antenna element 24, which is designed as at least one 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. The radar waves 14 transmitted from the sensor chip 28 to the first antenna element 24 are radiated by the first antenna element 24 as useful radiation 34 directly into the sensor environment 16.

[0044] Figure 2 shows a cross-section of a radar sensor in a 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.

[0045] The first antenna element 24 is designed as an opening 26 in the antenna surface 20 and causes the useful radiation 34 of the radar waves 14 directly into the sensor environment 16. However, surface waves 36 also emanate from the first antenna element 24 as surface-running radar waves, which are transmitted in the waveguide antenna 12 outside the waveguide, for example in the base body 18 and the antenna surface 20.

[0046] The waveguide antenna 12 comprises radiation means 38 configured to selectively radiate the surface waves 36 as secondary radiation 40 contributing to the useful radiation 34 in order to adapt an antenna pattern of the first antenna element 24 that characterizes the useful radiation 34. The surface waves 36 emanating from the first antenna element 24 are radiated at the radiation means 38 at a first radiation position 42 as secondary radiation 40 contributing to the useful radiation 34. For this purpose, the radiation means 38 have a first recess 44 in the antenna surface 20 that interrupts the surface material 22 and occupies a partial volume 46 in the base body 18 that adjoins the first recess 44 of the antenna surface 20 and has a filler material 48 that is different from the surface material 22 and a base body material of the base body 18.The first radiation position 42 is formed at a transition 50 between the base body material and the filling material 48.

[0047] Furthermore, the radiation means 38 have at least one second recess 52 in the antenna surface 20, which interrupts the surface material 22, and occupy a partial volume 46 in the base body 18 adjacent to the second recess 52 of the antenna surface 20, which is filled with the same filling material 48 as the partial volume 46 adjacent to the first recess 44. The partial volume 46 adjacent to the first and second recesses 44, 52 is arranged at least in sections below the surface material 22 of the antenna surface 20 and has a depth 68 relative to the antenna surface 20.

[0048] Figure 3 shows a cross-section of a radar sensor in a further specific embodiment of the invention. The surface waves 36 emanating from the first antenna element 24 are radiated by the radiating means 38 at a transition 50 between the base body material and the filler material 48 at a first radiating position 42 and at a second radiating position 54 offset therefrom as secondary radiation 40 contributing to the useful radiation 34. The radiating means 38 comprise a first radiating element 56, which is angled by an angle of incidence 58 relative to the antenna surface 20 and forms the second radiating position 54. The first radiating element 56 has, on a surface facing the base body 18, an electrically conductive surface material 62, at which the surface waves 36 are radiated into the sensor environment 16. The surface material 62 can be the surface material 22.The surface waves 36 can be reflected multiple times within the partial volume 46 between the first antenna element 24 and the first emission position 42 until they reach the second emission position 54. The reflection of the surface waves 36 can occur, on the one hand, at the transition 60 between the partial volume 46 and the base body 18 and, on the opposite side, at a rear side of the surface material 22.

[0049] The radiating means 38 further comprise a second radiating element 64 which radiates the surface waves 36 emanating from the first antenna element 24 on a side opposite the first radiating element 56 with respect to the first antenna element 24 at a second radiating position 54 as secondary radiation 40.

[0050] Figure 4 shows a cross-section of a radar sensor in another specific embodiment of the invention. The radiation means 38 are embodied as radiation means 38 structured on the antenna surface 20, which have a plurality of depressions 66 in the antenna surface 20. The depressions 66 are set back by a depth 68 from the antenna surface 20 and have slanted side walls 70. Furthermore, a transition 72 between the side walls 70 and the antenna surface 20 is preferably rounded. This simplifies the manufacture of the waveguide antenna 12. Furthermore, the scattering width of the emitted secondary radiation 40 can be increased.

[0051] Figure 5 shows a cross-section of a radar sensor in another specific embodiment of the invention. The surface waves 36 emanating from the first antenna element 24 and the surface waves 36 emanating from a second antenna element 71 are radiated by the radiating means 38 as secondary radiation 40 and contribute to the respective useful radiation 34 of the first and second antenna elements 24, 71. The recess 66 of the radiating means 38, arranged between the first and second antenna elements 24, 71, can radiate both the surface waves 36 of the first antenna element 24 and the surface waves 36 of the second antenna element 71 as secondary radiation 40.

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 a base body (18), an antenna surface (20) facing the sensor environment (16) and comprising a surface material (22) on the base body (18), and a first antenna element (24) designed as at least one opening (26) in the antenna surface (20) for radiating the radar waves (14) as useful radiation (34) directly into the sensor environment (16), characterized in that the waveguide antenna (12) has radiation means (38) which are configured to selectively radiate surface-running radar waves (14) forming surface waves (36) as secondary radiation (40) contributing to the useful radiation (34) for adapting an antenna pattern of the first antenna element characterizing the useful radiation (34). (24) to radiate.

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

3. Radar sensor (10) according to claim 1 or 2, characterized in that the radiation means (38) have at least one recess and / or depression (66) in the antenna surface (20) and / or an elevation relative to the antenna surface (20).

4. Radar sensor (10) according to one of the preceding claims, characterized in that the radiation means (38) occupy a partial volume (46) in the base body (18) which has a filling material (48) different from the surface material (22) and / or a base body material of the base body (18).

5. Radar sensor (10) according to claim 4, characterized in that the partial volume (46) is arranged at least in sections below the surface material (22) of the antenna surface (20).

6. Radar sensor (10) according to one of the preceding claims, characterized in that the radiation means (38) are arranged to radiate the surface waves (36) emanating from the first antenna element (24) into the sensor environment (16).

7. Radar sensor (10) according to one of the preceding claims, characterized in that the radiation means (38) are arranged to emit the secondary radiation (40) in each case with respect to the antenna surface (20) at a first radiation position (42) and at a second radiation position (54) offset therefrom.

8. Radar sensor (10) according to one of the preceding claims, characterized in that the radiating means (38) have at least one radiating element (56, 64) arranged at an angle of incidence (58) relative to the antenna surface (20).

9. Radar sensor (10) according to claim 8, characterized in that the radiating element (56, 64) has an electrically conductive surface material (62) at least on a surface facing the base body (18).

10. Radar sensor (10) according to one of the preceding claims, characterized in that the surface material (22) is electrically conductive.

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