Waveguide arrangement and radar sensor

Abstract

Waveguide arrangement (1), in particular for a radar sensor (6, 9a-9d), comprising a first carrier (2) having at least one arrangement of structures, a second carrier (3) having at least one arrangement of structures, wherein the structures each have a structural gap (6, 7) through which the waveguiding takes place, and the structures are arranged such that the structures of the first carrier (2) are oriented at an angle to one another with respect to the structures of the second carrier (3).

Description

[0001] The present invention relates to a waveguide arrangement or waveguide and a radar sensor comprising a waveguide arrangement according to the invention. Technological background

[0002] Modern means of transport, such as cars or motorcycles, are increasingly being equipped with driver assistance systems that use sensor systems to detect the surroundings, recognize traffic situations, and assist the driver, e.g., by braking or steering intervention or by issuing a visual or acoustic warning. Radar sensors, lidar sensors, camera sensors, or similar sensor systems are regularly used for environmental detection. Conclusions about the surroundings can then be drawn from the data acquired by the sensors. Environmental detection using radar sensors is based on the emission of bundled electromagnetic waves and their reflection, e.g., by other road users, obstacles on the road, or buildings along the edge of the road. Pedestrians are often detected using camera sensors, but radar sensors are also increasingly being used for this purpose.

[0003] For systems of the type described above, radar sensors can also be used in fusion with sensors using other technologies, such as camera or lidar sensors. Radar sensors have the advantage, among other things, that they operate reliably even in poor weather conditions and can measure not only the distance between objects but also their radial relative velocity directly using the Doppler effect. The transmission frequencies typically used are 24 GHz, 77 GHz, and 79 GHz. Due to the increasing functional scope of such systems, the requirements are constantly increasing, particularly with regard to the maximum detection range. In addition to environmental detection of motor vehicles for systems of the type described above, the focus is now also on interior monitoring of motor vehicles, e.g. to detect which seats are occupied; frequencies in the 60 GHz range, for example, are used for this purpose.

[0004] Generic radar sensors usually have an antenna, in particular one designed as a waveguide or hollow guide. So-called energy band gap structures (EBG) are used here, which use a periodic or quasi-periodic structure and a defined gap or structural gap to create a waveguide. The waveguide can be manufactured, for example, by combining two halves of the waveguide, which are then connected using different joining techniques such as soldering, dip soldering, or gluing. Furthermore, alignment techniques for the waveguide are later necessary, especially when an antenna, filter, coupler, or the like is constructed, to ensure proper function. Another technique is the so-called SIW (Substrate Integrated Waveguide).Substrate-integrated waveguide (SWT) is a waveguide in which a line designed as a waveguide consists of a dielectric coated on both sides, also called a substrate, and electrical vias as a boundary. Accordingly, this is a design in which the waveguide or waveguide component is integrated into the circuit board. Furthermore, the (entire) waveguide can also be manufactured or printed using 3D printing, eliminating the need for alignment. Printed state of the art

[0005] EP 3 248 243 B1 discloses a microwave device, such as a waveguide, a transmission line, a waveguide circuit, a transmission line circuit, or a radio frequency (RF) part of an antenna system, wherein the microwave device comprises two conductive layers arranged with a gap therebetween. The gap between the conductive layers is filled with air and lacks a dielectric substrate.The microwave device further comprises a set of periodically or quasi-periodically arranged protruding elements that are firmly connected to at least one of the conductive layers, thereby forming a texture to stop wave propagation in an operating frequency band in directions other than along the provided waveguide paths. At least one electrically conductive ridge is provided on at least one of the conductive layers and is not in electrical contact with the other of the two conductive layers, whereby the conductive ridge forms the waveguide paths. All of the protruding elements are electrically connected to one another at their bases at least via the conductive layer to which they are firmly connected and are also in conductive contact with the other conductive layer. Object of the present invention

[0006] Based on the prior art, the object of the present invention is to provide a waveguide or waveguide arrangement in which the requirements with regard to structural tolerances during the manufacture of the waveguide can be improved or reduced in a simple and cost-effective manner. Solution to the task

[0007] The above object is achieved by the entire teaching of claim 1 and the subordinate claim. Advantageous embodiments of the invention are claimed in the subclaims.

[0008] The waveguide arrangement according to the invention is, in particular, a waveguide for a radar sensor, comprising a first carrier having at least one arrangement of structures, and a second carrier having at least one arrangement of structures, which are arranged next to one another. The structures each have a structural gap through which the waveguiding essentially takes place, wherein the structures are arranged such that the structures of the first carrier are oriented at an angle to one another with respect to the structures of the second carrier. The waveguide according to the invention or the waveguide arrangement according to the invention for a radar sensor thus consists of two halves, which are preferably in direct contact with one another without a gap therebetween, wherein each of the two halves is configured with periodic or quasi-periodic ribs.The ribs of the two halves are not arranged parallel to each other, but are offset, e.g., at a certain angle. Ideally, the waveguide arrangement must be electrically conductive, i.e., at least the surface of the assembly should be electrically conductive. For example, a (metal-coated) plastic can be used, or the assembly can be made entirely of metal.

[0009] The structures are preferably elongated or oblong structures, in particular ribs, grooves, rectangular elements or the like.

[0010] Conveniently, the longitudinal axis of the structures of the first carrier and the longitudinal axis of the structures of the second carrier can be oriented at an angle to one another, wherein the longitudinal axes of the structures are oriented, for example, at an angle of approximately (i.e. with a deviation of, for example, + / - 5°) 45° or 60° or 75° or 90° to one another.

[0011] The structural elements or ribs create so-called hard and soft or hot and cold surfaces, which allow or disallow the propagation of waves. Due to the offset or crossing of the structural element directions or rib directions (i.e. the orientation of the structural elements or ribs) on both sides or supports, the waves cannot propagate into the structural element region or rib region, whereby this propagation is achieved in particular by the inventive orientation of the arrangements or structures or ribs. A structural gap, e.g. a section of ribs, also creates an area in which waves can propagate, so that waveguides and waveguide components such as couplers / splitters, radiators, etc. can form.

[0012] Furthermore, an additional structural element, in particular an additional rib, can be arranged or provided in the structural gap of the first carrier and / or the structural gap of the second carrier. In other words, additional structural elements, such as an additional rib or two additional parallel ribs (on one side or on each carrier), can be introduced into the structural gap, which make it possible to reduce the area required to create a waveguide or waveguide components compared to an "empty structural gap."

[0013] Conveniently, the additional structural element can protrude from the profile of the arrangement of structural elements, preferably in such a way that, when the supports are joined together, the additional structural element of one support protrudes into the structural gap of the other support.

[0014] Alternatively, the additional structural element may also be recessed compared to the profile of the arrangement of structural elements, i.e. protrude less than the other structural elements.

[0015] If the two supports or their structures have a (very small) gap between them due to constructional inaccuracies or tolerances, this gap can behave like an undesired waveguide. Nevertheless, this waveguide is loaded with a series of short-circuited stubs. The length and width of these stubs, as well as their spacing, can be selected to create a stopband for the required frequency range, which leads to a field limitation inside the waveguide. This allows for impedance matching, which can be used to improve attenuation or reduce the reflected wave.

[0016] Minor gaps between the structures or EBGs or rib structures, which arise due to structural unevenness and inaccuracies, can create unwanted tolerances without affecting the waveguide properties, so that the tolerance requirements for the respective components that form the waveguide can be reduced.

[0017] According to a particular embodiment of the invention, at least one, in particular short-circuited, stub line can be provided in order to generate a stop band for a frequency range.

[0018] Furthermore, the present invention also includes a radar sensor having a waveguide arrangement according to the invention. Description of the invention using exemplary embodiments

[0019] The invention is described in more detail below using practical embodiments. They show: Fig. 1 a simplified representation of an embodiment of a waveguide according to the invention with two halves, on each of which there is a rib structure, each of which has a structural gap ( Fig. 1A Exploded view in unfolded or unassembled state, Fig. 1B Top view of the upper beam and Fig. 1C Side view of the supports); Fig. 2 a simplified representation of an embodiment of a waveguide according to the invention with two halves, on each of which there is a rib structure, each of which has a structural gap, wherein an additional rib is provided in the structural gap of the lower half ( Fig. 2A Exploded view in unfolded or unassembled state, Fig. 2B Top view of the upper beam and Fig. 2C Top view of the lower beam); Fig. 3 a simplified representation of an embodiment of a waveguide according to the invention with two halves, on each of which there is a rib structure, each having a structural gap, wherein an additional rib is provided in the structural gaps of the lower and upper halves ( Fig. 3A Exploded view in unfolded or unassembled state, Fig. 3B Top view of the upper beam and Fig. 3C Top view of the lower beam); Fig. 4 a simplified schematic representation of the relationship between return loss and frequency for a waveguide without additional rib according to Fig. 1 with different gaps S (gap=0 mm, gap=0.15 mm or gap=0.3 mm) between the halves; Fig. 5 a simplified schematic representation of the relationship between return loss and frequency for a waveguide with an additional rib according to Fig. 2 with different gaps S (gap=0 mm, gap=0.15 mm or gap=0.3 mm) between the halves; Fig. 6 a simplified schematic representation of the relationship between return loss and frequency for a waveguide with two additional ribs according to Fig. 3 with different gaps S (gap=0 mm, gap=0.15 mm or gap=0.3 mm) between the halves, as well as Fig. 7 a simplified schematic representation of an embodiment of a vehicle with at least one radar sensor according to the invention.

[0020] In Fig. 1A shows a first embodiment of a waveguide or waveguide arrangement according to the invention. The waveguide 1 is made of an upper half or first support 2 and a lower half or second support 3. The upper half has a rib or groove structure made of ribs 4 and the lower half 3 has a groove structure made of ribs 5. The groove structures or corrugations are offset or rotated by 90 degrees to one another, so that the alignment of the ribs 4 and the ribs 5, ie their longitudinal axes, are oriented at right angles to one another. For the sake of clarity, Fig. 1B a plan view of the lower support 3 and in Fig. 1C shows a side view of the supports 2, 3. The rib structures on the upper and lower supports 2, 3 are also interrupted by centrally arranged structural gaps 6, 7, which, when the supports 2, 3 are assembled, form a common channel that ultimately forms the waveguide. The groove structures serve to prevent wave propagation to the sides, so that the waves are only guided through the common channel. The ribs 4 are, as can be seen particularly in Fig. 1B, are arranged perpendicular to the ribs 5 and their longitudinal axes are arranged at approximately 90° or orthogonally to each other.

[0021] The design according to Fig. 1 has no additional rib in the common channel. In Fig. 2A-C shows an embodiment in which an additional rib 8 is provided on the lower support 3 (these could of course also be provided on the upper support 2). Fig. 3 an alternative embodiment in which an additional rib 8, 9 is provided on each of the two supports 2, 3, which then protrude into the common channel.

[0022] In the Fig. Figures 4-6 show the return loss for different distances or tolerance-related gaps between the two halves, which emulate an undesirable gap between the halves due to part tolerances. Different gaps S (S=0 mm, S=0.15 mm, and S=0.3 mm - simplified in the figures as S(0), S(0.15), and S(0.3)) were simulated. As shown in the Fig. As shown in Figures 4-6, the return loss (expressed in dB) is still within an acceptable range even with a distance or gap of 0.3 mm across a wide frequency band (expressed in GHz). Therefore, it can be seen that the inventive solution, or rather the introduction of the hard / soft surface, provides a waveguide with reduced tolerance requirements regarding the gap between the halves (i.e., the negative effects on return loss caused by structural tolerances are reduced by the invention).

[0023] Reference number 11 in Fig.7 denotes a vehicle which has a control device 12 (ECU, Electronic Control Unit or ADCU, Assisted and Automated Driving Control Unit), various actuators (steering 13, engine 14, brake 15) and sensors for detecting the environment (radar sensor 16, camera 17, lidar sensor 18 and radar sensors 19a-19d). The vehicle 11 can be controlled (partially) automatically in that the control device 12 can access the actuators and the sensors or their sensor data. In the area of ​​assisted or (partially) automated driving, the sensor data can be used for environmental and object recognition, so that various assistants or assistance functions, such as distance control (ACC, Adaptive Cruise Control), emergency braking assistant (EBA, Electronic Brake Assist), lane keeping control or a lane keeping assistant (LKA, Lane Keep Assist), parking assistant, traffic jam assistant or the like, can be controlled via the control device 12 orthe algorithm stored therein. Furthermore, the radar sensors 16 or 19a-19d may be radar sensors that have a waveguide arrangement according to the invention. LIST OF REFERENCE SYMBOLS 1 waveguide arrangement 2 first carrier 3 second carrier 4 ribs 5 ribs 6 Structural gap 7 Structural gap 8 (additional) rib 9 (additional) rib 11 vehicles 12 Control device 13 Steering 14 Engine 15 Brake 16 radar sensor 17 Camera 18 Lidar sensor 19a Radar sensor 19b Radar sensor 19c radar sensor 19d radar sensor QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 3 248 243 B1

[0005]

Claims

[1] Waveguide arrangement (1), in particular waveguide for a radar sensor (6, 9a-9d), comprising a first carrier (2) comprising at least one arrangement of structures, a second carrier (3) comprising at least one arrangement of structures, wherein the structures each have a structural gap (6, 7) through which the waveguiding takes place, and the structures are arranged such that the structures of the first carrier (2) are oriented at an angle to each other with respect to the structures of the second carrier (3). [2] Waveguide arrangement (1) according to claim 1, characterized by that elongated structures, in particular ribs, grooves or the like, are provided as structures. [3] Waveguide arrangement (1) according to claim 1, characterized by that the longitudinal axis of the structures of the first carrier (2) and the longitudinal axis of the structures of the second carrier (3) are oriented at an angle to each other. [4] Waveguide arrangement (1) according to claim 3, characterized by that the longitudinal axes of the structures are oriented at an angle of approximately 45°, 60°, 75° or 90° to each other. [5] Waveguide arrangement (1) according to one of the preceding claims, characterized by that an additional structural element, in particular an additional rib (8, 9), is provided in the structural gap (6) of the first support (2) and / or the structural gap (7) of the second support (3). [6] Waveguide arrangement (1) according to claim 4, characterized by that the additional structural element protrudes from the profile of the arrangement of structural elements, preferably in such a way that the additional structural element of one support protrudes into the structural gap of the other support. [7] Waveguide arrangement (1) according to one of the preceding claims, characterized by that the additional structural element is inferior to the profile of the arrangement of structural elements. [8] Waveguide arrangement (1) according to one of the preceding claims, characterized by that at least one, in particular short-circuited, stub line is provided in order to generate a stop band for a frequency range. [9] Radar sensor (11, 19a-19d) comprising a waveguide arrangement (1) according to one of the preceding claims.

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