Waveguide apparatus, radar sensor and vehicle

Abstract

The invention relates to a waveguide apparatus (1), in particular for a radar sensor (11, 18a-18d), comprising a first waveguide section (2) comprising three wall elements (2a, 2b, 2c) which are arranged on one another and are arranged in such a way that the first waveguide section (2) has three closed sides and has an opening (3), and a second waveguide section (4) comprising three wall elements (4a, 4b, 4c) which are arranged on one another and are arranged in such a way that the second waveguide section (4) has three closed sides and has an opening (5), wherein the wall element (2b) of the first waveguide section (2), which is arranged opposite the opening (3) of the first waveguide section (2), has a recess (6), and the first waveguide section (2) and the second waveguide section (4) are arranged on one another in such a way that the opening (5) of the second waveguide section (4) is arranged at the recess (6) of the first waveguide section (2).

Description

[0001] 202406220

[0002] 1

[0003] Waveguide device, radar sensor and vehicle

[0004] The present invention relates to a waveguide device for a radar sensor, a corresponding radar sensor with a waveguide device according to the invention for a vehicle, and a vehicle which has a radar sensor according to the invention.

[0005] Technological background

[0006] Modern vehicles such as cars and motorcycles are increasingly equipped with driver assistance systems (ADAS). These systems use sensors to perceive the environment, recognize traffic situations, and support the driver, for example, by applying the brakes or steering, or by issuing visual or audible warnings. Radar sensors, lidar sensors, cameras, and similar devices are commonly used for environmental perception. The sensor data collected by these devices allows for inferences to be drawn about the surroundings. Radar sensors are used for environmental perception by emitting focused electromagnetic waves and reflecting them back, for example, from other road users, obstacles on the road, or roadside structures.

[0007] The radar sensors used in systems of the type described above are often combined with sensors from other technologies, such as cameras or lidar. Radar sensors have the advantage of operating reliably even in adverse weather conditions and, in addition to measuring the distance to objects, can also directly measure their radial relative velocity via the Doppler effect. Transmission frequencies of 24 GHz, 77 GHz, and 79 GHz are typically used. As the functionality of such systems increases, the requirements, particularly regarding maximum detection range, are constantly rising. Besides the environmental sensing of vehicles for systems of the type described above, the monitoring of vehicle interiors is also becoming increasingly important, for example, to detect which seats are occupied; frequencies in the 60 GHz range are used for this purpose.

[0008] Modern radar sensors often employ waveguide antennas. Rectangular waveguides are particularly common in these applications. Such rectangular waveguides are closed and typically have four walls in cross-section. For example, if one wall on the short side of a rectangular waveguide is removed...

[0009] Internal 202406220

[0010] When the waveguide structure or device reaches a certain size, it assumes an extreme impedance value. This makes it very difficult to match this waveguide to another waveguide type in a waveguide-to-waveguide transition. One way to tune the waveguide structure to a more suitable impedance value is to increase the width-to-height ratio. At a certain point in this growth, the impedance approaches that of a rectangular waveguide enclosed on one short side with a perfect magnetic conductor, at the cost of introducing higher-order modes and a significant increase in size.

[0011] Printed state of the art

[0012] From US 3,015,100 A, a waveguide is known that has a transmission line with two parallel side walls connected by a bottom wall, the side walls being completely open at their upper edges and thus forming a waveguide structure with a trough-shaped cross-section that is substantially constant over its entire length, wherein a center conductor is arranged symmetrically within the substantially trough-shaped waveguide structure and extends along its length. Furthermore, means for generating and controlling the radiation from the open top of the trough-shaped waveguide structure are provided, the means being arranged such that they cause an asymmetry with respect to a lateral cross-section of the waveguide. Finally, means are provided in the waveguide to eliminate reflections caused by the radiation-generating means.

[0013] Furthermore, a waveguide antenna system is known from US 2023 / 085413 A1, which consists of an electromagnetic (EM) transition section and a leaky waveguide antenna section. The EM transition section comprises a transition area with a signal input interface and an open waveguide section or leaky waveguide antenna section, wherein the EM transition section is configured to couple EM energy from the signal input interface via the transition area into a guided waveguide mode of EM energy in the leaky waveguide antenna section. The leaky waveguide antenna section is configured and arranged such that it radiates electromagnetic energy received from the open waveguide section, wherein the EM transition section is electromagnetically coupled to the leaky waveguide antenna section, and wherein the EM transition section is configured to transmit

[0014] Internal 202406220

[0015] 3 electromagnetic energy is supported from a signal feed structure to the leakage waveguide antenna section.

[0016] Furthermore, HONG, WEI, ET AL. describe a half-mode substrate integrated waveguide (HMSIW) for microwave and millimeter wave applications in "Half-mode substrate integrated waveguide: A new guided wave structure for microwave and millimeter wave application" (Joint 31st International Conference on Infrared Millimeter Waves and 14th International Conference on Terahertz Electronics. IEEE, 2006). The measurement results described therein in the microwave and millimeter wave ranges show that the attenuation is lower than with conventional microstrips or surface integrated waveguides (SIWs), while the size of the HMSIW is only about half that of an SIW. In this way, the size of an integrated microwave or millimeter wave circuit based on this new guided waveguide structure can be further reduced.

[0017] The HMSIW presented in "Half mode substrate integrated waveguide: A new guided wave structure for microwave and millimeter wave application" (HONG, WEI, ET AL) is a refined approach that uses dielectric loading to control the waveguide impedance and field confinement. It incorporates all the advantages of a rectangular waveguide, such as robustness under tolerance variations and ease of processing, combined with the compactness of a half-mode approach. However, the dielectric loading significantly increases losses compared to an air- or vacuum-filled rectangular waveguide. In general, high losses, coupled with the additional cost of the dielectric material, are some of the main disadvantages of an HMSIW.

[0018] Another approach to the "one-sided open rectangular waveguide" is a ridge-loaded open waveguide, as known from US 2023 / 085413 A1. The propagating TE01 mode is well confined, and the air or vacuum filling ensures very low losses. Radiation from such a waveguide can be achieved by breaking the symmetry along the central axis, whereby breaking the symmetry energy from the propagating non-radiating TE01 is transferred to a radiating TE01 mode. This simple method of generating radiation from an "open waveguide" is also one of its greatest disadvantages: Any deviation from symmetry, such as the position of the ridge relative to the walls or the size of the ridge itself, produces unwanted radiation, which can make the entire system susceptible to tolerance-related problems.

[0019] Internal 202406220

[0020] 4

[0021] Object of the present invention

[0022] Starting from the prior art, the object of the present invention is to provide a waveguide or waveguide device and a radar sensor of the generic type, in which an improvement or reduction of losses can be achieved in a cost-effective manner while maintaining good robustness and simple manufacturing.

[0023] Solution to the task

[0024] The foregoing problem is solved by the entire teaching of claim 1 and the dependent claims. Advantageous embodiments of the invention are claimed in the dependent claims.

[0025] The waveguide device according to the invention is particularly intended for a radar sensor used in vehicles for object detection. The waveguide device comprises a first waveguide section comprising three adjacent wall elements or side walls arranged such that the first waveguide section has three closed sides and one opening, and a second waveguide section comprising three adjacent wall elements arranged such that the second waveguide section has three closed sides and one opening.The wall element of the first waveguide section, which is arranged opposite the opening of the first waveguide section, further has a recess, wherein the first waveguide section and the second waveguide section are arranged next to each other, such that the opening of the second waveguide section is arranged at the recess of the first waveguide section.

[0026] According to a preferred embodiment of the invention, structures, in particular protruding structures such as pins, cylinders, EBG (electromagnetic band gap) structures, or the like, are provided on at least one of the wall elements of the first waveguide section. This allows the return loss and insertion loss of the semi-mode open waveguide to be further improved. Alternatively or additionally, recesses, holes, or other extrusions can also be provided.

[0027] Internal 202406220

[0028] 5

[0029] Advantageously, the structures can be arranged on two opposite sides of the first waveguide section.

[0030] Preferably, the structures on the opposite sides of the first waveguide section are arranged in a mirror-symmetric manner or follow higher symmetries (e.g., they can be glide-symmetric).

[0031] Advantageously, the recess of the first waveguide section extends over the entire length of the wall element of the first waveguide section.

[0032] According to a particular embodiment of the waveguide device, a kink can be provided, which changes the spatial orientation of the waveguide. Advantageously, the kink can be rounded or chamfered.

[0033] Furthermore, the present invention comprises a radar sensor, in particular for object detection for a vehicle, with a high-frequency component for generating and / or receiving RF signals or radar signals and a semi-mode waveguide device or waveguide arrangement open at one end according to the invention for coupling in and / or out the radar signals or RF signals.

[0034] Furthermore, the present invention claims a motor vehicle or vehicle which has a radar sensor according to the invention.

[0035] The invention will now be described in more detail using practical embodiments. The figures show:

[0036] Fig. 1 shows a simplified 3D representation of a first embodiment of a waveguide device according to the invention;

[0037] Fig. 2 shows a simplified cross-sectional view through the waveguide device from Fig. 1;

[0038] Fig. 3 shows the return loss of an embodiment of an open semi-mode waveguide according to the invention;

[0039] Internal 202406220

[0040] 6

[0041] Fig. 4 shows the insertion loss of an embodiment of an open semi-mode waveguide according to the invention;

[0042] Fig. 5 shows a simplified 3D representation of a second embodiment of a waveguide device according to the invention with structures on two opposing wall elements of the first waveguide section;

[0043] Fig. 6 shows a simplified cross-sectional view through the waveguide device from Fig. 5;

[0044] Fig. 7 shows the return loss of an embodiment of an open semi-mode waveguide according to the invention with an AMC layer;

[0045] Fig. 8 shows the insertion loss of an embodiment of an open semi-mode waveguide according to the invention with an AMC layer;

[0046] Fig. 9 shows a further embodiment of a semi-modern open waveguide according to the invention with a rounded kink;

[0047] Fig. 10 shows a further embodiment of a semi-modern open waveguide according to the invention with an oblique bend;

[0048] Fig. 11 shows a further embodiment of a semi-mode open waveguide according to the invention with a rounded kink and AMC layer or with an arrangement of structures;

[0049] Fig. 12 shows a further embodiment of a semi-mode open waveguide according to the invention with an oblique bend and AMC layer or with an arrangement of structures;

[0050] Fig. 13 shows a simplified 3D representation of a further embodiment of a waveguide device according to the invention with structures designed as holes on two opposing wall elements of the first waveguide section;

[0051] Fig. 14 shows a simplified cross-sectional view through the waveguide device from Fig. 13;

[0052] Internal 202406220

[0053] 7

[0054] Fig. 15 shows a simplified 3D representation of a further embodiment of a waveguide device according to the invention with a P-shaped cross-section;

[0055] Fig. 16 shows a simplified cross-sectional view through the waveguide device from Fig. 15, as well as

[0056] Fig. 17 shows a simplified representation of an embodiment of a vehicle according to the invention.

[0057] Figures 1 and 2 show an embodiment of a waveguide device according to the invention.

[0058] Figure 1 shows the invention. According to the invention, an open waveguide without extreme impedance values ​​is generated by stacking or arranging two rectangular (open at one end) waveguides one above the other. First, a first, in particular larger, waveguide section 2 is arranged with three wall sections 2a, 2b, 2c, such that this essentially rectangular waveguide has one open side or opening 3 (particularly in cross-section). Furthermore, a second waveguide section 4, in particular a flatter, smaller waveguide, is arranged comprising three wall elements 4a, 4b, 4c (with one side wall or wall element 4b being located on the underside), such that the second waveguide section 4 has three closed sides and an opening 5 (particularly in cross-section).The wall element 2b of the first waveguide section 2, which is arranged opposite the opening 3 of the first waveguide section 2, also has a recess 6 which preferably extends over the entire length of the waveguide or waveguide section 2, wherein the first waveguide section 2 and the second waveguide section 4 are arranged such that the opening 5 of the second waveguide section 4 is adjacent to the recess 6 of the first waveguide section.

[0059] 2 is arranged. This arrangement causes the smaller waveguide (on the underside) to merge with the larger waveguide, creating a T- or P-shaped waveguide, or any variation in between. The top side of the first waveguide section 2 is (completely) open. In this way, the waveguide structure or waveguide device can be manufactured very easily, e.g., by injection molding, sheet metal forming, thixoforming, 3D printing, or the like. Preferably, the waveguide device can be manufactured as a single-piece component. Figure 3 shows the return loss associated with one embodiment of the waveguide device according to the invention, and Figure 4 shows the corresponding insertion loss.

[0060] Internal 202406220

[0061] 8

[0062] The presented waveguide structure can be further improved, as shown in the embodiments in Figures 5 and 6, to reduce the potential radiation loss and insertion loss by an arrangement of periodic, quasi-periodic, or random structures 7, in particular protrusions and extrusions on the "long" wall elements 2a, 2c of the larger waveguide section 2. Such structures 7 or protrusions are preferably mirror-symmetric or can follow higher symmetries, such as sliding symmetry. The proposed "stacked" waveguide or t / p-shaped waveguide offers excellent insertion and radiation loss with and without protrusions, so that an improvement or reduction in losses can be achieved in a simple and cost-effective manner while maintaining good robustness within tolerances and being easy to manufacture.Furthermore, the proposed waveguide structure features a type of half-mode wave propagation that is robust against tolerances, while simultaneously exhibiting an air / vacuum filling with very low loss and low cost. Figure 7 shows the return loss of one embodiment of the waveguide device according to the invention, and Figure 8 shows the corresponding insertion loss.

[0063] In summary, a half-mode open waveguide is presented, in which one half-mode is used for wave propagation. This allows the waveguide to be constructed without metallic walls on all sides, resulting in a waveguide with one open end. This can, for example, save costs by requiring less material. Since the half-mode waveguide is manufactured without the use of substrate material, it exhibits no dielectric losses. A magnetic wall can be used to further improve the performance of the open half-mode waveguide. The magnetic wall ensures that the field distribution within the waveguide remains intact, even though the waveguide is open on one side. The magnetic wall can be created by or encompass a perfect magnetic conductor (PMC).Since a true perfect magnetic conductor (PMC) layer does not yet exist, an artificial magnetic conductor (AMC) layer can be provided at the open end of the waveguide. An AMC layer can be constructed in various ways, for example, by creating a grid of pins with sliding symmetry on the open side of a waveguide. The pin grid can be placed, for instance, on the upper and lower walls of the open end of the waveguide. The dimensions of the half-mode waveguide and the AMC layer are preferably optimized to improve the return loss and insertion loss.

[0064] Internal 202406220

[0065] 9

[0066] Furthermore, Figs. 9 to 12 show different embodiments of the waveguide device 1 according to the invention, wherein Fig. 9 shows a semi-mode open waveguide with a rounded bend 8, Fig. 10 shows a semi-mode open waveguide with an oblique or beveled bend 9, Fig. 11 shows a semi-mode open waveguide with a rounded bend 8 and AMC layer (or an arrangement of structures or projections), and Fig. 12 shows a semi-mode open waveguide with an oblique or beveled bend 9 and AMC layer (or an arrangement of structures or projections).

[0067] Figures 13 and 14 show a further embodiment of the waveguide device 1 according to the invention, in which the structures 7 are configured as holes or recesses. Figures 14 and 15 also show an embodiment of the waveguide device 1 in which a P-shaped waveguide is formed or provided, which can have structures on one or more wall elements in the same way as previously described embodiments. The P-shaped waveguide is characterized in that it has the recess 6 on the lower (or the upper) side of the wall element 2b, so that wall element 2c and wall element 4c preferably merge flush into one another (or, if the recess 6 is provided at the other end of the wall element 2b, wall element 2a and wall element 4a merge flush into one another).

[0068] Furthermore, Fig. 17 shows a vehicle 10 according to the invention, which has several radar sensors 11, 18a-18d 4 according to the invention with a waveguide device according to the invention (which is not shown in Fig. 13 for clarity). Reference numeral 12 in Fig. 6 designates a control unit (ECU, Electronic Control Unit or ADCU, Assisted and Automated Driving Control Unit) by which sensor control, sensor data fusion, environment and / or object detection, trajectory planning and / or vehicle control can be carried out, in particular in an assistive and / or (semi-)autonomous manner. For vehicle control, the control unit 12 can access various actuators (steering 13, motor 14, brake 15). In addition to the radar sensors 11, 18a-18d, the vehicle 10 also has further sensors (Lidar sensor 7, camera 8) for environment detection. The sensor data can be advantageously used for environment and object recognition, enabling various assistance functions, such as...B. Emergency Brake Assist (EBA), Adaptive Cruise Control (ACC), Lane Keep Assist (LKA), or similar systems can be implemented. Furthermore, the execution of these assistance functions can also be carried out via control unit 12 or another designated control unit.

[0069] Internal 202406220

[0070] 10

[0071] REFERENCE MARK LIST

[0072] 1 Waveguide device

[0073] 2 first waveguide section

[0074] 2a-2c wall element

[0075] 3 Opening

[0076] 4 second waveguide section

[0077] 4a-4c wall element

[0078] 5 Opening

[0079] 6 Exclusion

[0080] 7 Structure

[0081] 8. Bend point (round)

[0082] 9. Crease point (diagonal)

[0083] 10 vehicles

[0084] 11 Radar sensor

[0085] 12 Control unit

[0086] 13 Steering

[0087] 14 engine

[0088] 15 Brake

[0089] 16 Lidar sensor

[0090] 17 Camera

[0091] 18a-18d radar sensor

[0092] Internal

Claims

202406220 11 PATENT CLAIMS 1. Waveguide device (1), in particular for a radar sensor (11, 18a-18d), comprising a first waveguide section (2), comprising three wall elements (2a, 2b, 2c) arranged one after the other, such that the first waveguide section (2) has three closed sides and an opening (3), and a second waveguide section (4), comprising three wall elements (4a, 4b, 4c) arranged one after the other, such that the second waveguide section (4) has three closed sides and an opening (5), wherein the wall element (2b) of the first waveguide section (2), which is arranged opposite the opening (3) of the first waveguide section (2), has a recess (6), and the first waveguide section (2) and the second waveguide section (4) are arranged one after the other, such that the opening (5) of the second waveguide section (4) is arranged at the recess (6) of the first waveguide section (2). is.

2. Waveguide device (1) according to claim 1, characterized in that at least on one of the wall elements of the first waveguide section (2), structures (7), in particular pins, cylinders, EBG (Electromagnetic Band Gap) structures, holes, recesses, extrusions or the like, are provided.

3. Waveguide device (1) according to claim 2, characterized in that the structures (7) are arranged on two opposite sides (2a, 2c) of the first waveguide section (2).

4. Waveguide device (1) according to claim 3, characterized in that the structures (7) on the opposite sides (2a, 2c) are arranged in a mirror-symmetric manner or follow higher symmetries, preferably sliding-symmetric.

5. Waveguide device (1) according to one of the preceding claims, characterized in that the recess (6) extends over the entire length of the wall element (2b) of the first waveguide section (2). Internal 202406220 12 6. Waveguide device (1) according to one of the preceding claims, characterized in that a kink (8, 9) is provided, through which the spatial orientation of the waveguide changes.

7. Waveguide device (1) according to claim 6, characterized in that the kink is rounded or chamfered.

8. Radar sensor (11, 18a-18d), in particular for object detection for a vehicle (10), comprising a waveguide device (1) according to one of the preceding claims.

9. Vehicle (10) comprising a radar sensor (11, 18a-18d) according to claim 8. Internal

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