Installation space-optimized absorber funnel for a radar sensor of a vehicle, and vehicle

Abstract

One aspect of the invention relates to an absorber (4) for a radar sensor (2) of a vehicle (1), the absorber (4) having an accommodation region (7) for a radar sensor (2) and the accommodation region (7) defining a vertical and / or transverse axis (8) of the absorber (4). When the radar sensor (2) is arranged as intended, the absorber (4) is arranged in sections around a predetermined capture region (5) of the radar sensor (2). At least sections of an inner side (6) of the absorber (4) that faces the predetermined capture region (5) are designed to be stepped by way of absorption surfaces (10). The absorption surfaces (10) that design at least sections of the inner side (6) that faces the predetermined capture region (5) to be stepped are inclined vis-à-vis the vertical and / or transverse axis (8) of the absorber (4) at a predetermined inclination angle (φ).

Description

[0001] SPACE-OPTIMIZED ABSORBER FUNNEL FOR A

[0002] RADAR SENSOR OF A VEHICLE, VEHICLE

[0003] The present invention relates to an absorber for a radar sensor of a vehicle. Furthermore, the present invention relates to a vehicle with such an absorber.

[0004] Radar sensor absorbers, also called absorber cones, are essential components of modern radar sensors in the automotive sector. Absorber cones typically form a (protective) shield or collar to minimize unwanted radar reflections and absorb radar beams that arrive outside the desired detection range of the radar sensor. This can usually increase the sensor sensitivity and accuracy of the radar sensor.

[0005] Absorber cones are often made of foam-based radar-absorbing materials (RAM). For example, a urethane foam enriched with conductive carbon black (carbonyl iron particles and / or crystalline graphite particles) can be used. However, a polymer (e.g., polyamide or polycarbonate) loaded with carbon is often used as the radar-absorbing material. Absorber cones can also incorporate radar-absorbing structures (RAS), such as pyramid-shaped structures. These structures can also be made of microwave-absorbing material. However, since the available space in a vehicle is always valuable and limited, the absorber cone must be designed to both fulfill its function and be small enough to blend harmoniously into the vehicle's design.

[0006] The document DE 10 2012 017 669 A1 relates to an arrangement for a motor vehicle, comprising a trim part, in particular a bumper, and comprising a radar sensor which is designed to emit electromagnetic waves through the trim part for the detection of target objects and to receive radiation echoes from target objects. The radar sensor has a simultaneous detection angle through which a field of view of the radar sensor is defined in the azimuthal direction, and the radar sensor is arranged at a distance from a rear side of the trim part such that the azimuthal field of view of the radar sensor intersects the trim part in an intersection region. To absorb interference waves outside the azimuthal detection angle, an absorption material is applied to the rear side of the trim part in the azimuthal direction outside the intersection region, the intersection region being free of absorption material.

[0007] The object of the present invention is to demonstrate a solution for further improving absorbers for radar sensors or absorber cones. It is considered particularly advantageous if this saves installation space without functional restrictions and simplifies integration into the vehicle design.

[0008] This object is achieved by the features of the independent claims. Further advantageous embodiments of the invention are specified in the dependent claims.

[0009] One aspect of the invention relates to an absorber for a radar sensor of a vehicle, wherein the absorber has a receiving area for a radar sensor, wherein the receiving area defines a vertical and / or a transverse axis of the absorber. When the radar sensor is arranged as intended, the absorber is arranged in regions around a predetermined detection area of ​​the radar sensor. An inner side of the absorber facing the predetermined detection area is at least partially stepped by absorption surfaces. The absorption surfaces, which at least partially step the inner side facing the predetermined detection area, are inclined at a predetermined angle of inclination relative to the vertical and / or transverse axis of the absorber.

[0010] The absorber can minimize unwanted radar reflections between a radar sensor radome and the radar sensor itself. The radome can be formed, for example, by a panel component (e.g., front or rear apron, headlight cover, or the like) and can protect the radar sensor from environmental influences, particularly precipitation and stone chips. Although the radome is transparent to electromagnetic radiation in a wavelength range of the radar sensor, disruptive reflections always occur, albeit to a small extent, which can be minimized using the absorber.

[0011] The absorber can be arranged between the radome and the radar sensor. If the radome is formed by a vehicle trim panel, the distance between the radome and the radar sensor can be predetermined. Furthermore, the predetermined detection range of the radar sensor is typically also predetermined (for example, due to the functional requirements of a wide variety of driver assistance systems). According to the current state of the art, this leads to a predetermined installation space requirement for the radar sensor's absorber. By using the absorber according to the invention, the installation space requirement predetermined by the aforementioned framework conditions can now be reduced without functional restrictions.

[0012] First, the absorber has a receiving area for the radar sensor. In principle, the absorber can have a conical shape in the transmitting or receiving direction of the radar sensor. This means that a cross-sectional area defined by the receiving area can be smaller than a cross-sectional area of ​​the absorber or radome defined by an exit area. The exit area describes an area from which electromagnetic radiation emitted by the radar exits. Consequently, when the radar sensor is properly arranged, the absorber is arranged in sections (e.g., in a collar, shield, or funnel shape) around the predetermined detection area of ​​the radar sensor.

[0013] The vertical and / or transverse axis of the absorber can now be defined using the detection area. This axis can, in particular, correspond to a Cartesian coordinate system of the radar sensor. The definition of the vertical and / or transverse axis can subsequently be used to describe a relative position of the inner side facing the predetermined detection area.

[0014] The geometrically complex detection ranges of modern radar sensors typically mean that a cross-section of the absorber can correspond to any (convex) quadrilateral, a convex polygon, or the like. The inner surfaces of the absorber can therefore (at least in some areas) correspond to flat surfaces or flat planes.

[0015] In order to reduce the installation space required by the inner sides of the absorber, which can be predetermined due to the predetermined detection range of the radar sensor and the distance between the radar sensor and the radome, the inner side of the absorber facing the predetermined detection range can be designed in a stepped manner, at least in some regions, by absorption surfaces. This stepped arrangement can therefore save installation space. The absorption surfaces, which at least in some regions form a stepped manner on the inner side facing the predetermined detection range, can be inclined at the predetermined angle of inclination with respect to the vertical and / or transverse axis of the absorber. This can prevent the electromagnetic radiation emitted by the radar sensor from being reflected back to the radar sensor in the form of an interference signal due to multiple reflection and thus affecting the performance of the radar sensor.In other words, a reflection reflected from the radome via the inside of the absorber back to the radar sensor can be deflected away from the radar sensor by tilting it at a predetermined angle. Overall, this can improve the performance of the radar sensor. The predetermined angle of inclination can, for example, be in the range of 4° to 10°. It can be particularly advantageous if the predetermined angle of inclination is in the range of 6° to 8°.

[0016] One embodiment of the absorber provides that a step formed by one of the absorption surfaces runs along a transmission direction of the radar sensor. In principle, it is conceivable for the step to run both along the transmission direction of the radar sensor and transversely to the transmission direction. If the step formed by the absorption surfaces runs along the transmission direction, the installation space can be reduced, particularly for a predetermined detection range that is (significantly) extended in the azimuth direction. Analogously, the installation space can also be reduced for a predetermined detection range that is (significantly) extended in the elevation direction. However, the latter is usually less relevant for a radar sensor for automotive applications. It can also be advantageous if one inner side, which is at least partially stepped, corresponds at least substantially to a (flat) plane if the step shape is neglected.

[0017] In a further possible embodiment of the absorber, one of the absorption surfaces is provided with structural elements for scattering incident electromagnetic radiation in a wavelength range of the radar sensor. The absorption surfaces are intended to prevent multiple reflections of the electromagnetic radiation emitted by the radar sensor from being reflected back to the radar sensor in the form of an interference signal, thereby affecting the performance of the radar sensor. Therefore, the absorption surfaces, which form the inner side facing the predetermined detection area in a stepped manner at least in some regions and are inclined according to the predetermined angle of inclination relative to the vertical and / or transverse axis of the absorber, can additionally have structural elements for scattering the incident electromagnetic radiation.Thus, the absorption surfaces can deflect the incoming electromagnetic radiation, while the absorption surfaces can scatter the incoming electromagnetic radiation. This can reduce the power of electromagnetic radiation reflected back to the radar sensor in doubtful cases (i.e., when electromagnetic radiation is reflected back despite being deflected by the absorption surfaces). Interference signals can thus be reduced. The performance of the radar sensor can thus be further increased.

[0018] A further embodiment of the absorber provides that the structural elements are wave-shaped to scatter the incident electromagnetic radiation. The wave-shaped structural elements can, for example, also be a semi-cylindrical elevation or depression, which can optionally also be distorted. The wave-shaped structural elements can, in particular, correspond to a planar wavefront. A wave-shaped structural element can, for example, run along the transmission direction of the radar sensor. If a step formed by the absorption surfaces also runs along the transmission direction of the radar sensor, the wave-shaped structural element or a planar wavefront can be arranged parallel to the step shape.

[0019] The wave-shaped structural elements can cause the electromagnetic radiation deflected away from the radar sensor to be further scattered. This ensures that, in cases of doubt (i.e., when electromagnetic radiation is reflected back despite being deflected by the absorption surfaces), the reflected electromagnetic radiation is reduced, or the power, and thus the strength, of the interference signal reaching the radar sensor's receiving antenna is reduced. The waveform ensures that the scattering occurs only in an intended spatial direction, so that almost no interference signals, which could be directly attributed to the scattering itself, are directed to the radar sensor.

[0020] It can therefore be advantageous if the structural elements for scattering the incoming electromagnetic radiation are designed in a wave-like manner along the radar sensor's transmission direction. Alignment along the radar sensor's transmission direction can enable targeted scattering of the incoming electromagnetic radiation. This prevents unwanted scattering in the direction of the radar sensor itself. Furthermore, the actual function of the absorber can also be improved.

[0021] Another embodiment of the absorber provides for the wave-shaped structural elements to have a height of 1 mm to 6 mm. Furthermore, the wave-shaped structural elements can have a spatial period of 1 mm to 6 mm. Tests have shown that such wave-shaped structural elements are particularly suitable for scattering electromagnetic radiation in the frequency range of automotive radar sensors (approximately 76 to 80 GHz).

[0022] This may be particularly related to the resulting wavelength of about 4 mm.

[0023] In a further possible embodiment of the absorber, it is provided that a collar shape of the absorber, by means of which the absorber is arranged in regions around the predetermined detection range of the radar sensor, is formed essentially by four planes. The term "essentially by four planes" refers to the shape of the inner sides of the absorber, provided that the at least partially stepped design is neglected. The shape of the cavity defined by the absorber can therefore be - neglecting the at least partially stepped design - for example, any convex cuboid, with at least one of the sides being at least partially stepped.

[0024] An absorber whose basic shape is essentially formed by four planes offers particularly significant potential for saving installation space. The absorption surfaces can be tilted at a predetermined angle relative to the vertical and / or transverse axes of the absorber, which is particularly advantageous. This allows for targeted deflection of the incoming electromagnetic radiation.

[0025] A further embodiment of the absorber provides that at least two of the four planes forming the collar shape of the absorber form the inner side of the absorber facing the predetermined detection area and are thus formed, at least in some regions, in a stepped manner by absorption surfaces. Typically, the predetermined detection area of ​​automotive radar sensors is significantly larger in the azimuth direction than in the elevation direction. Consequently, the required installation space can be significantly reduced simply by forming at least two of the four planes shielding the predetermined detection area in the azimuth direction. Furthermore, the functionality of the absorber can be retained at the same time.

[0026] In another possible embodiment of the absorber, the inner side of the absorber facing the predetermined detection area, which is stepped at least in some regions by absorption surfaces, comprises at least five steps. The more steps the inner side of the absorber facing the predetermined detection area has, the more installation space can be saved. With a step height of, for example, 4 mm (in the range of the radar sensor's wavelength), the installation space can be reduced by as little as 15 mm to 20 mm.

[0027] A further aspect of the invention relates to a vehicle comprising a radar sensor and a radome. The radome is configured to protect the radar sensor from environmental influences and to be permeable to electromagnetic radiation in a wavelength range of the radar sensor. Furthermore, the vehicle according to the invention comprises an absorber for the radar sensor of the vehicle, wherein the absorber has a receiving area for the radar sensor, wherein the receiving area defines a vertical and / or a transverse axis of the absorber. When the radar sensor is arranged as intended, the absorber is arranged in regions around a predetermined detection area of ​​the radar sensor. An inner side of the absorber facing the predetermined detection area is formed in a stepped manner, at least in regions, by absorption surfaces.The absorption surfaces, which form the inner side facing the predetermined detection area in a stepped manner at least in some areas, are inclined at a predetermined angle relative to the vertical and / or transverse axis of the absorber. The vehicle can be designed, in particular, as a passenger car.

[0028] The preferred embodiments presented with reference to the absorber according to the invention and their advantages apply accordingly to the vehicle according to the invention.

[0029] Further features of the invention emerge from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0030] The invention will now be explained in more detail using preferred embodiments and with reference to the accompanying drawings.

[0031] Fig. 1 is a schematic representation of a vehicle comprising a radar sensor, a radome and an absorber for the radar sensor,

[0032] Fig. 2 is a front view of an absorber, the inside of which is at least partially stepped,

[0033] Fig. 3a is a sectional view of an absorber according to Fig. 2 in a side view,

[0034] Fig. 3b is a schematic representation of a beam path of a reflected electromagnetic radiation within the absorber in the sectional view according to Fig. 3a, and

[0035] Fig. 4 is a sectional view of an absorber according to Fig. 2 in a plan view,

[0036] In the figures, identical or functionally identical elements are provided with the same reference symbols.

[0037] Fig. 1 shows a schematic representation of a vehicle 1 comprising a radar sensor 2, a radome 3, and an absorber 4 for the radar sensor 1. When the radar sensor 2 is arranged as intended, the absorber 4 encloses a predetermined detection area 5 of the radar sensor 2 in sections, particularly in a collar shape. The predetermined detection area 5 is indicated in Fig. 1 by the dashed-dotted lines.

[0038] Fig. 2 shows a front view of an absorber 4, the inner side 6 of which is at least partially stepped. The absorber 4 has a receiving area 7 for a radar sensor 2, wherein the receiving area 7 defines a vertical and / or a transverse axis 8 of the absorber 4. A comparable absorber 4 according to the prior art or its inner sides would essentially be formed by four planes E. In contrast, the absorber 4 or two of the inner sides 6 of the absorber 4 facing the predetermined detection area from Fig. 2 are at least partially stepped by absorption surfaces 10. The absorption surfaces 10, which form the two inner sides 6 facing the predetermined detection area 5 at least partially stepped, are inclined relative to the vertical and / or transverse axis 8 of the absorber 4 at a predetermined angle of inclination (p).The at least partially stepped formation of the inner side 6 by the absorption surfaces 10 leads to a space saving A compared to a comparable absorber 4 according to the prior art.

[0039] Furthermore, the absorption surfaces 10 of the absorber 4 shown in Fig. 2 have structural elements 11 for scattering incident electromagnetic radiation in a wavelength range of the radar sensor 2. The step formed by one of the absorption surfaces 10 runs along a transmission direction of the radar sensor 2. The structural elements 11 for scattering the incident electromagnetic radiation are wave-shaped and also run along a transmission direction of the radar sensor 2. By aligning them along the transmission direction of the radar sensor 2, targeted scattering of the incident electromagnetic radiation can be achieved. This prevents unwanted scattering in the direction of the radar sensor 4.

[0040] Fig. 3a shows a sectional view of an absorber 4 according to Fig. 2 in a side view, wherein the radar sensor 2 is not visible in Fig. 3a. Fig. 3b shows a schematic representation of a beam path 12 of reflected electromagnetic radiation within the absorber 4 in the sectional view according to Fig. 3a. Due to the absorption surfaces 10 inclined at the predetermined angle of inclination (p) with respect to the vertical and / or transverse axis 8 of the absorber 4, the electromagnetic radiation reflected back by the radome 3 can be deflected upwards in such a way that no interference signal reaches the radar sensor 2 (note that the predetermined angle of inclination (p) may not be correctly drawn in the figures due to the perspective).

[0041] Finally, Fig. 4 shows a sectional view of an absorber 4 according to Fig. 2 in a plan view. List of reference symbols

[0042] 1 vehicle

[0043] 2 radar sensors

[0044] 3 Radome

[0045] 4 absorbers

[0046] 5 predetermined detection area

[0047] 6 Inside

[0048] 7 Recording area

[0049] 8 Vertical and / or transverse axis

[0050] 9 Plane 0 Absorption surfaces 1 Structural element 2 Beam path P Predetermined angle of inclination

[0051] A Space saving

Claims

Claims 1. Absorber (4) for a radar sensor (2) of a vehicle (1), wherein - the absorber (4) has a receiving area (7) for a radar sensor (2), wherein the receiving area (7) defines a vertical and / or a transverse axis (8) of the absorber (4), - the absorber (4) is arranged in regions around a predetermined detection area (5) of the radar sensor (2) when the radar sensor (2) is arranged as intended, - an inner side (6) of the absorber (4) facing the predetermined detection area (5) is formed at least partially in a stepped manner by absorption surfaces (10), and - the absorption surfaces (10), which form the inner side (6) facing the predetermined detection area (5) in a stepped manner at least in some areas, are inclined at a predetermined angle of inclination (cp) relative to the vertical and / or transverse axis (8) of the absorber (4).

2. Absorber (4) according to claim 1, characterized in that a step formed by one of the absorption surfaces (10) runs along a transmission direction of the radar sensor (2).

3. Absorber (4) according to claim 1 or 2, characterized in that one of the absorption surfaces (10) has structural elements for scattering incident electromagnetic radiation in a wavelength range of the radar sensor (2).

4. Absorber (4) according to claim 3, characterized in that the structural elements (11) are wave-shaped for scattering the incident electromagnetic radiation.

5. Absorber (4) according to claim 4, characterized in that the structural elements (11) for scattering the incident electromagnetic radiation are wave-shaped along a transmission direction of the radar sensor (2).

6. Absorber (4) according to one of claims 4 or 5, characterized in that the wave-shaped structural elements (11) have a height of 1 mm to 6 mm.

7. Absorber (4) according to one of the preceding claims, characterized in that a collar shape of the absorber (4), by means of which the absorber (4) is arranged in regions around the predetermined detection area (5) of the radar sensor (2), is formed essentially by four planes (9).

8. Absorber (4) according to claim 7, characterized in that at least two of the four planes (9) which form the collar shape of the absorber (4) form the inner side (6) of the absorber (4) facing the predetermined detection area (5) and are consequently formed in a stepped manner at least in some areas by absorption surfaces (10).

9. Absorber (4) according to one of the preceding claims, characterized in that the inner side (6) of the absorber (4) facing the predetermined detection area (5), which is formed in a step-like manner at least in regions by absorption surfaces (10), comprises at least five steps.

10. Vehicle (1), comprising: - a radar sensor (2), - a radome (3) which is designed to protect the radar sensor (2) from environmental influences and is permeable to electromagnetic radiation in a wavelength range of the radar sensor (2), and - an absorber (4) according to one of claims 1 to 9, wherein the absorber (4) is arranged between the radar sensor (2) and the radome (3).

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