Waveguide arrangement, radar sensor and vehicle

Abstract

The present invention relates to a waveguide arrangement (1) for a radar sensor (16, 19a, 19b, 19c, 19d), comprising a circuit board (2) having at least one high-frequency component with at least one element for directly emitting or receiving the radar signals, an antenna (3) having one or more individual antennas for transmitting and / or receiving radar signals with a definable wavelength, wherein the antenna (3) comprises at least one waveguide (4a, 4b) which is delimited by a plurality of side walls, and at least one side wall is formed by the circuit board (2) and the side walls comprise a metal layer, in particular a metal coating, wherein at least one recess (5) is provided in at least one side wall of the waveguide (4a, 4b), the size of which recess is smaller than the wavelength of the emitted radar signals.

Description

[0001] The present invention relates to a waveguide arrangement for a radar sensor, a corresponding radar sensor comprising a waveguide arrangement according to the invention, and a vehicle having at least one radar sensor 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 roadway, 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, interior monitoring of motor vehicles is now also becoming a focus, e.g. to detect which seats in the vehicle are occupied; frequencies in the 60 GHz range, for example, are used for this purpose.Waveguide antennas have been used in radar sensors for several years. These antennas enclose the electromagnetic waves within solid conductive walls and transport them to their final destination. The waveguides used are often bulky, and when soldered onto circuit boards, they take up a lot of space, necessitating larger circuit boards and greater routing complexity, which in turn increases manufacturing complexity and costs. Therefore, there is a particular interest in reducing the size of the circuit boards used in conventional radar sensors, thereby reducing manufacturing complexity and costs. Printed state of the art

[0004] DE 10 2018 203 106 A1 discloses a radar system for detecting the surroundings of a motor vehicle with a separate plastic antenna, wherein the plastic antenna has one or more individual antennas for transmitting and / or receiving radar signals and a circuit board comprising at least one high-frequency component with at least one element for direct radiation or reception. The plastic antenna is manufactured from a single piece and arranged on the side of the circuit board opposite the at least one high-frequency component. The at least one radiating or receiving element is designed such that it radiates towards the circuit board or can receive from the direction of the circuit board. For this purpose, the circuit board is permeable to radar waves in the region of the at least one radiating or receiving element, wherein an input or output coupling point is located on the plastic antenna at the permeable point of the circuit board. Object of the present invention

[0005] Based on the prior art, the object of the present invention is to provide an antenna for a radar device with which the circuit board size can be reduced and thus also the manufacturing effort and costs can be reduced. Solution to the task

[0006] The above object is achieved by the entire teaching of claim 1 and the subordinate claims. Advantageous embodiments of the invention are claimed in the subclaims.

[0007] The waveguide arrangement according to the invention for a radar sensor comprises a circuit board (or substrate, printed circuit board, PCB or the like) having at least one high-frequency component with at least one element for directly emitting or receiving the radar signals, an antenna having one or more individual antennas for transmitting and / or receiving radar signals with a definable wavelength, wherein the antenna comprises at least one waveguide delimited by several side walls. At least one side wall is realized or formed by the circuit board, wherein the side walls (and thus possibly also the circuit board at least in the region of the waveguide) comprise a metal layer, in particular a metal coating. Furthermore, at least one recess is provided in at least one side wall of the waveguide, the size of which recess is smaller than the wavelength of the emitted radar signals.

[0008] By arranging (electrically small) recesses or cutouts in the substrate or in a side that forms the waveguide, vias can be created in normally occupied areas. This results in the advantage that less complex routing is required, which can lead to a smaller circuit board size. Furthermore, vias that are only partially drilled through the circuit board (microvias) can be avoided. Both of these reduce manufacturing effort and thus also manufacturing costs. A further advantage of vias in the waveguide is that they create escape paths for solder gases, which facilitates production. To further reduce the problem with solder gases, similar cutouts can be implemented in waveguide walls that are not soldered to the circuit board. This can further reduce manufacturing effort.The technology according to the invention can be used in all areas in which waveguides are used - preferably in the high-frequency or optical range.

[0009] Preferably, several recesses are provided in the side walls or thus also in the circuit board.

[0010] Conveniently, the at least one recess can thus also be provided in the side wall of the waveguide formed by the circuit board.

[0011] Furthermore, the metal layer may comprise copper or a copper alloy. This may be a layer disposed on the sidewalls. Furthermore, it may simply be a coating applied (e.g., vapor-deposited or deposited) to the sidewalls or antenna and / or the circuit board.

[0012] Advantageously, a plastic antenna can be provided as the antenna, which has at least partially a metal coating.

[0013] According to a particular embodiment of the invention, the waveguide can be aligned either vertically or horizontally.

[0014] Preferably, the recess is circular in shape; in particular, it can be a bore whose diameter is smaller than the wavelength of the emitted radar signals. For example, for radar radiation with a frequency of approximately 75 GHz and a wavelength of approximately 4 mm, a diameter of the recesses smaller than 4 mm could be provided.

[0015] Furthermore, the present invention also comprises a radar sensor, in particular for a vehicle, which has a waveguide arrangement according to the invention, and a vehicle which comprises or has such a radar sensor. Description of the invention using exemplary embodiments

[0016] The invention is described in more detail below using practical embodiments. They show: Fig. 1 a simplified representation of a part of an embodiment of a waveguide arrangement according to the invention with vertically aligned waveguides; Fig. 2 a simplified representation of a part of a further embodiment of a waveguide arrangement according to the invention with horizontally aligned waveguides; Fig. 3 a simplified representation of part of a further embodiment of a waveguide arrangement according to the invention; Fig. 4 a simplified representation of the antenna gain (gain in dBi) for various design variants of a waveguide arrangement, wherein the solid curve shows the profile of the reference radiation pattern of a conventional radar sensor without recesses, the dashed curve shows the profile of the radiation pattern using a design according to the invention with recesses and the dotted curve shows the profile of the radiation pattern with a design with inappropriately arranged recesses, and Fig. 5 a simplified schematic representation of an embodiment of a vehicle which has at least one radar sensor according to the invention.

[0017] The Fig. 1-3 show exemplary implementations of a waveguide arrangement 1 according to the invention, wherein in the Fig. 1-3, a part of a circuit board 2 and a part of an antenna 3 are shown. The waveguide arrangement 1 comprises the circuit board 2 (or substrate, printed circuit board, PCB or the like), which has at least one high-frequency component with at least one element for directly transmitting or receiving radar signals, wherein the antenna 3, which is preferably a plastic-enclosed antenna or plastic antenna, has one or more individual antennas for transmitting and / or receiving the radar signals with a definable wavelength. The antenna 3 comprises at least one waveguide, which is delimited by several side walls. In Fig. 1 the waveguide is a vertical waveguide 4a and in Fig. 2 as a horizontal waveguide 4b. Furthermore, at least one side wall is realized or formed by the circuit board 2, wherein the side walls (and thus possibly also the circuit board at least in the region of the waveguide) comprise a metal layer, in particular a metal coating. Advantageously, the metal layer can comprise copper or a copper alloy. In addition, at least one recess 5 is provided in at least one side wall of the waveguide 1, the size of which is smaller than the wavelength of the transmitted radar signals (e.g. also their dimensions (radius, diameter, length, width or the like). The recesses 5 are in the Fig. In the embodiments shown in Figures 1-3, the recesses 5 are arranged in the side wall formed by the circuit board 2, but could also be provided in other side walls of the waveguide 4a or 4b, e.g., in the side walls formed by the antenna 3. The recesses 5 are also circular in shape; in particular, they can be a bore extending through the side wall, the diameter of which is smaller than the wavelength of the transmitted radar signals.

[0018] In Fig. Figure 3 shows the implementation in part of an antenna 3. When cutouts or recesses 5 are made in the circuit board 2 or printed circuit board, energy can escape. If the energy is allowed to propagate, this leads to a slight deterioration of the radiation pattern, as shown in Fig. 4, where the radiation pattern at Phi = 0 shows no recesses (solid line), few and advantageously arranged recesses (dashed line) and disadvantageously arranged recesses (dotted curve), whereby a difference is particularly noticeable for marginal or extreme angles.

[0019] Reference number 11 in Fig.5 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 or an antenna with a waveguide arrangement according to the invention. LIST OF REFERENCE SYMBOLS 1 waveguide arrangement 2 circuit boards 3 Antenna 4a Waveguide 4b Waveguide 5 Recess 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] DE 10 2018 203 106 A1

[0004]

Claims

[1] Waveguide arrangement (1) for a radar sensor (16, 19a, 19b, 19c, 19d), comprising a circuit board (2) comprising at least one high-frequency component with at least one element for directly transmitting or receiving the radar signals, an antenna (3) comprising one or more individual antennas for transmitting and / or receiving radar signals with a definable wavelength, wherein the antenna (3) comprises at least one waveguide (4a, 4b) which is delimited by several side walls, and at least one side wall is formed by the board (2) and the side walls comprise a metal layer, in particular a metal coating, characterized by , that at least one recess (5) is provided in at least one side wall of the waveguide (4a, 4b), the size of which recess is smaller than the wavelength of the emitted radar signals. [2] Waveguide arrangement (1) according to one of the preceding claims, characterized by that several recesses (5) are provided. [3] Waveguide arrangement (1) according to one of the preceding claims, characterized by that the at least one recess (5) is provided in the side wall of the waveguide (4a, 4b) formed by the circuit board (2). [4] Waveguide arrangement (1) according to one of the preceding claims, characterized by that the metal layer comprises copper or a copper alloy. [5] Waveguide arrangement (1) according to one of the preceding claims, characterized by that a plastic antenna is provided as the antenna (3), which at least partially has a metal coating. [6] Waveguide arrangement (1) according to one of the preceding claims, characterized by that the waveguide (4a, 4b) is aligned either vertically or horizontally. [7] Waveguide arrangement (1) according to one of the preceding claims, characterized by that the recess (5) is circular, in particular is a bore whose diameter is smaller than the wavelength of the emitted radar signals. [8] Radar sensor (16, 19a, 19b, 19c, 19d) comprising a waveguide arrangement (1) according to one of the preceding claims. [9] Vehicle (11) comprising a radar sensor (16, 19a, 19b, 19c, 19d) according to claim 8.

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