Radar antenna device for vehicle, vehicle, and method for manufacturing radar antenna device

Abstract

The invention relates to a radar antenna device (1) for a vehicle (20), comprising a composite window pane (2) and at least one radar device (13) configured to transmit and / or receive a radar beam (6). The at least one radar device (13) comprises a corresponding antenna unit (5) and a corresponding amplifier unit (12). The amplifier unit (12) is configured to provide an electrical drive signal (8) to the antenna unit (5) and / or to receive an electrical echo signal (9) from the antenna unit (5). The invention provides that the antenna unit (5) is arranged in the composite window pane (2) of the vehicle (20), the amplifier unit (12) is arranged on a surface of the composite window pane (2), and the antenna unit (5) and the amplifier unit (12) are spatially separated from each other and are electrically conductively connected to each other via a connecting element (11) arranged in the composite window pane.

Description

[0001] The invention relates to a radar antenna arrangement for a vehicle, a vehicle and a method for producing a radar antenna arrangement.

[0002] A variety of technologies are used to detect a vehicle's surroundings. These include, for example, optical detection of the surroundings using a camera, detection using a LIDAR system, or detection using a radar sensor. The advantage of radar sensors is that, unlike LIDAR or camera systems, they are not affected by poor visibility. Radar sensors can accurately detect the surroundings even in darkness or fog.

[0003] However, achieving high resolution requires a radar antenna system with multiple radar units. Furthermore, to achieve the required angular accuracy, the radar antenna system must have a certain surface area. A radar antenna system enables detection of the environment by determining the phase of the signals received by the respective radar antenna units. This presents two major challenges. The first is the synchronization of the individual radar antenna units. Because the angle of incidence of the signal is determined by phase measurement, the time of signal reception must be determined with the necessary accuracy. Another challenge arises from the relative positioning of the individual radar antenna units. Therefore, the precise position of the individual radar antenna units relative to one another must be determined. The windshield of a motor vehicle is a suitable surface for the radar antenna system because it provides the required surface area and enables a rigid arrangement of the individual radar antenna units.

[0004] For example, DE 10 246 607 B4 discloses an electrochromic radar sensor. The electrochromic radar sensor comprises an electrochromic layer arrangement. Here, the radar sensor device is arranged in the propagation direction of electromagnetic waves emitted from the observed object.

[0005] FR 2 235 502 A1 discloses a device for detecting or emitting various electromagnetic waves used in radio and television broadcasting or for radar, wherein a strip or powder of electrically conductive material is integrated into a substance applied or bonded to a surface.

[0006] US Pat. No. 5,682,168 A discloses a concealed vehicle antenna, wherein one or more antenna elements are provided below a covered cover above a roof rack of the vehicle or behind the front grille of the vehicle.

[0007] The technical problem to be solved by the present invention is to provide a radar antenna unit in the window glass of a vehicle (or transportation means).

[0008] According to the present invention, a radar antenna assembly for a vehicle is provided. The radar antenna assembly includes a composite window pane and at least one radar device configured to transmit and / or receive a radar beam. The at least one radar device includes a corresponding antenna unit and a corresponding amplifier unit. The amplifier unit is configured to provide an electrical drive signal to the antenna unit and / or receive an electrical echo signal from the antenna unit. The antenna unit of the antenna assembly is disposed in the composite window pane of the vehicle. The amplifier unit is disposed on a surface of the composite window pane. The antenna unit and the amplifier unit are spatially separated from each other and are electrically conductively connected to each other via a connecting element disposed in the composite window pane.

[0009] In other words, the radar antenna device includes a composite window pane, which can be, for example, a vehicle windshield. The composite window pane can have multiple layers fixed to one another. The radar device's antenna unit is arranged within the composite window pane. Thus, for example, the antenna unit is arranged between two layers of the composite window pane or integrated into one layer. The radar device's amplifier unit is arranged on the outside of the composite window pane. The amplifier unit and antenna unit are spatially separated and therefore do not contact each other. The amplifier unit is configured to provide the electrical drive signal to be transmitted by the antenna unit. To this end, the amplifier unit and antenna unit are electrically conductively connected to each other via a connecting element. The connecting element is also configured to transmit electrical echo signals received by the antenna unit to the amplifier unit.

[0010] The invention provides the advantage that the radar antenna arrangement can be arranged in a composite pane.

[0011] The invention also includes refinements which yield additional advantages.

[0012] A further development of the present invention provides that the composite glazing comprises at least two glass layers, with the antenna unit being arranged between the glass layers. In other words, the composite glazing is a multi-layer arrangement comprising at least two glass layers. The glass layers are arranged adjacent to one another, with the at least one antenna unit being located between the glass layers. For example, it may be provided that the at least two glass layers are connected to one another by a synthetic resin, with the antenna unit being incorporated into the synthetic resin arranged between the two glass layers.

[0013] A further development of the present invention provides that the connecting element is arranged in a hole in the composite glazing. In other words, the composite glazing has a hole extending through at least one layer of the composite glazing. The connecting element for electrically contacting the amplifier unit with the antenna unit is arranged in this hole. For example, it can be provided that the hole extends from the surface of the composite glazing to the antenna element and is filled with a conductive material.

[0014] A further development of the present invention provides that the connecting element is arranged perpendicular to the antenna unit. In other words, the connecting element extends parallel to the normal to the surface of the antenna unit. This results in the advantage that no radiation is emitted via the connecting element that would affect the radiation provided by the antenna unit. For example, it can be provided that the antenna unit has a rod antenna or a patch antenna arranged in the plane of the composite window. The connecting element can be arranged perpendicular to the antenna unit.

[0015] A further embodiment of the present invention provides that the composite glazing comprises at least one film layer, wherein the antenna element is printed (or imprinted) onto the film layer. In other words, the antenna element is provided on the film layer of the composite glazing. The shape of the antenna element can be provided by a printing method by applying a conductive material to the film layer. This offers the advantage that complex antenna element structures can be provided using common and simple methods. For example, it can be provided that the film layer consists of a polymer, wherein the antenna element is applied by inkjet printing or screen printing.

[0016] A further embodiment of the present invention provides for a coating in the glass layer to include the antenna element. In other words, the antenna element is applied directly to the glass layer. This offers the advantage that no additional layers need to be applied. For example, it may be provided that the antenna element is applied to the glass layer by sputtering or evaporation. To provide the desired structure of the antenna element, a mask may be placed on the composite window pane during the coating process, or subsequent etching may be performed to remove the applied layer.

[0017] An extension of the present invention provides that the composite glazing has at least one optical waveguide (or light guide), wherein the at least one optical waveguide is connected to the amplifier unit via an optical coupling element. In other words, the composite glazing includes a volume provided for optically guiding the optical signal. The optical coupling element is located on the amplifier unit and reflects at least a portion of the light of the optical signal guided through the optical waveguide to the amplifier unit. This extension has the advantage that the optical waveguide does not need to be additionally fixed to the outside of the composite glazing. For example, it can be provided that a specific material different from the material of the glass layer is added in one direction of the composite glazing. Due to the different refractive indices, light can be guided along the optical waveguide. In order to be able to convey a portion of the guided light to the amplifier unit, an optical coupling element can be arranged on the optical waveguide, which guides a portion of the light into the amplifier unit.

[0018] A refinement of the present invention provides that one of the glass layers has conductor tracks that are in electrical contact with the amplifier unit. In other words, the glass layer has tracks made of an electrically conductive material that are electrically conductively connected to the amplifier unit in order to supply it with current. This refinement offers the advantage that contact can be made with the amplifier unit via the composite glass.

[0019] The present invention also includes a vehicle having a radar antenna arrangement. The vehicle may be, for example, a car or a truck.

[0020] The present invention also includes a method for manufacturing a radar antenna system for a vehicle. The radar antenna system to be manufactured comprises a composite window pane and at least one radar system configured to transmit and / or receive radar beams, wherein at least one radar system comprises a corresponding antenna unit and a corresponding amplifier unit. The amplifier unit is configured to provide an electrical drive signal to the antenna unit and / or to receive an electrical echo signal from the antenna unit. The method provides for the antenna unit and a connecting element to be arranged in the composite window pane. The amplifier unit is arranged on a surface of the composite window pane. In the method, the antenna unit and the amplifier unit are electrically conductively connected to each other via the connecting element arranged in the composite window pane.

[0021] In other words, the radar antenna system includes at least one radar system, wherein during the method, the antenna unit of the radar system is arranged so that it is located within the composite window pane. This can be achieved, for example, by placing the antenna unit on a first glass layer covered with a second glass layer. This allows the antenna unit to be located between the two glass layers, thereby being located within the composite window pane. To electrically connect the antenna unit to the amplifier unit, a connecting element is provided within the composite window pane during the method. This can be achieved, for example, by drilling a hole into one of the glass layers and then placing the connecting element within the hole. In a final step, the amplifier unit can be placed on the composite window pane and connected to the antenna unit via the connecting element. For this purpose, the amplifier unit can be soldered to the connecting element, for example.

[0022] The present invention also includes refinements of the vehicle according to the invention and the method according to the invention, which have the features already described in conjunction with the refinements of the radar antenna arrangement according to the invention. For this reason, the corresponding refinements of the vehicle according to the invention and the method according to the invention will not be described further here.

[0023] The invention also includes combinations of features of the described embodiments.

[0024] Next, an embodiment of the present invention will be described. In the accompanying drawings:

[0025] Figure 1 A radar antenna arrangement for a vehicle is shown;

[0026] Figure 2 shows a radar antenna arrangement in a composite glazing; and

[0027] Figure 3 A further radar antenna arrangement is shown in a composite pane.

[0028] The exemplary embodiments described below are preferred embodiments of the present invention. In the exemplary embodiments, the components described in these embodiments each represent individual, independently considered features of the present invention, which also independently extend the present invention and are therefore considered to be components of the present invention, either individually or in combinations other than those shown. Furthermore, the described embodiments may be supplemented by other features of the present invention that have already been described.

[0029] In the figures, functionally identical elements are each provided with the same reference numerals.

[0030] Figure 1 A radar antenna system for a vehicle is shown. Radar antenna system 1 may include a composite window pane 2. For example, composite window pane 2 may include a first glass layer 3 and a second glass layer 4. An antenna unit 5, which may be configured to transmit and / or receive a radar beam 6, may be arranged between first glass layer 3 and second glass layer 4. Antenna unit 5 may be composed, for example, of gold, silver, copper, aluminum, or another electrically conductive material. Antenna unit 5 may be applied to first glass layer 3, for example, by evaporation or sputtering. Antenna unit 5 may have a predetermined geometry and may be configured, for example, as a patch antenna or a rod antenna. To achieve the geometric shape, antenna unit 5 may be applied using a mask. Alternatively, first glass layer 3 may be completely coated with material, and excess areas removed by etching or sputtering to obtain antenna unit 5.

[0031] Second glass layer 4 can be arranged on first glass layer 3 via synthetic resin 7. To enable electrical drive signal 8 to be supplied to antenna element 5 or to enable forwarding of electrical echo signal 9 received by antenna element 5, provision can be made in second glass layer 10, produced using a drill or laser. Connecting element 11, which can be produced by introducing a conductive material into hole 10, can be arranged in hole 10. Antenna element 5 can be electrically conductively connected to amplifier unit 12 via connecting element 11, and together they form radar device 13. Amplifier unit 12 can be arranged on the surface of second glass layer 4. Amplifier unit 12 can be configured to receive optical drive signal 14, convert the optical drive signal into electrical drive signal 8, and transmit it to antenna element 5 via connecting element 11. Amplifier unit 12 can also be configured to receive electrical echo signal 9 via connecting element 11 and convert it into optical echo signal 15.

[0032] Amplifier unit 12 can be connected to optical conductor 17 (or light guide) via optical coupling element 16. Optical coupling element 16 can be configured to couple optical driver signal 14 from optical conductor 17 into amplifier unit 12 or to couple optical echo signal 15 from amplifier unit 12 into optical conductor 17. Optical conductor 17 can be formed, for example, from glass fibers and arranged on second glass layer 4. Optical coupling element 16 can be, for example, a grating coupler, a butt coupler, or an adiabatic coupler. Metal conductor tracks 18 can be arranged in second glass layer 4 to supply current to amplifier unit 12 or to dissipate heat from amplifier unit 12.

[0033] Figure 2 The radar antenna arrangement in a composite glazing is shown. The radar antenna arrangement 1 comprises a plurality of radar devices 13, each having corresponding antenna elements 5 and corresponding amplifier units 12, which are arranged spaced apart from one another and connected to one another via corresponding connecting elements 11. It can be provided that the antenna elements 5 are applied to a film using a printing method. The film 19 can be adhesively bonded to the first glass layer 3. The second glass layer 4 can be arranged on the film 19 itself. The corresponding amplifier units 12 can be arranged on the surface of the second glass layer 4.

[0034] Figure 3 The radar antenna arrangement in a composite window pane is shown. For example, the antenna unit 5 can be configured as a rod antenna. A connecting unit 11 can electrically conductively connect the antenna unit 5 to a corresponding amplifier unit 12. The connecting unit 11 can be arranged perpendicular to the composite window pane 2. This prevents a portion of the electromagnetic field radiated by the connecting unit 11 from influencing the electromagnetic field of the antenna unit 5. The amplifier unit 12 can be optically connected via an optical fiber 17. The antenna arrangement 1 can be arranged, for example, in a vehicle 20, which can be a car or truck. The composite window pane 2 can be, for example, the front or rear window of the vehicle 20.

[0035] The new radar antenna system 1 uses photon-integrated amplifier units 12 (so-called radar chips) to form large radar arrays. Amplifier units 12 can be positioned behind the windshield. Here, amplifier units 12 and antenna units 5 are separate, so that only antenna units 5 are integrated into the windshield. The high-frequency connection (connection element 11) between amplifier unit 12 and the corresponding antenna unit 5 is created by a hole filled with conductive material (mechanically or using a laser).

[0036] By integrating the antenna unit 5 directly into the composite pane 2 , a highly precisely arranged antenna array can be produced which allows a spatial extension of more than one meter and thus enables angular separability of 0.1° and below.

[0037] Here, the antenna unit 5 can be integrated, for example, by the following method:

[0038] One embodiment may provide for the prefabrication and installation of the antenna unit 5 in a multilayer arrangement (sandwich structure) consisting of the glass layers 3, 4 of the composite glazing 2. Subsequently, the individual glass layers 3, 4 of the composite glazing 2 may be brought together, thereby simultaneously securing the antenna unit 5 in its position. For this purpose, the antenna unit 5 may be prefabricated and installed in the composite glazing 2 between the glass layers 3, 4.

[0039] Another embodiment can provide for metallization of the glass side surfaces of the first glass layer 3 and subsequent material removal (by laser, sputtering, etching, etc.) to obtain the antenna element 5 with a predetermined antenna geometry. Metal conductor tracks 18 can be integrated into the composite pane 2 for electrical contacting the amplifier unit 12. Alternatively, the uppermost glass layer 4 can be etched away in the location of the amplifier unit 12, so that the amplifier unit 12 is connected to the structured metallized surface via a flip-chip connection. The conductor tracks 18 can also serve to cool the amplifier unit 12.

[0040] One embodiment provides for the antenna unit 5 to be printed on a film and integrated into the composite window pane 2. The individual amplifier units 12 are synchronized here via optical fibers. The optical fibers are also used for signal transmission of the transmitted (Tx) and received (Rx) radar signals at optical frequencies. As an alternative to individual fiber optic lines, in the above-described embodiment, waveguides can also be introduced directly into the glass (PLC). The waveguides conduct the Tx and Rx radar signals, converted into the optical frequency range, to the individual amplifier units 12. The optical contact between the amplifier units 12 and the waveguides can be established via grating couplers, butt couplers, or adiabatic couplers. This allows for a single optical coupling point on the front window pane that distributes all the signals of the radar chip.

[0041] Perceiving the surroundings as safely as possible is crucial for automated driving. The surroundings are detected using radar, LIDAR, and cameras. 360° 3D detection of the environment as a whole is particularly important, so that all static and dynamic objects are detected. LIDAR plays a key role in redundant, stable environmental detection, since this sensor type allows precise distance measurements during environmental detection and can also be used for classification. However, these sensors are expensive and complex in their design. 360° 3D environmental detection is particularly problematic, since either many smaller individual sensors are required to ensure this (these typically work with many individual light sources and detector elements), or large sensors are installed. However, the smaller sensor types are still limited to 10×10×10 cm in their spatial dimensions. 3 range and no invisible installation locations have been permitted so far.

[0042] Furthermore, the data collected by each sensor must be processed and / or combined individually, where accurate timestamps are crucial for real-time processing, making data detection and classification more complex.

[0043] In the field of passive safety systems, and for Level 4 and 5 automated driving, the ability to distinguish between traffic participants is particularly important not only for protecting passengers but also for protecting other road users. For this purpose, safe environmental perception is crucial. To ensure this, the surroundings must be perceived with the highest possible resolution in all three spatial dimensions. Modern cameras and LIDAR systems can provide environmental perception, but their quality suffers or they become completely ineffective in conditions of poor visibility, such as fog, snow, or darkness. Radar sensors, in contrast, do not suffer from these limitations but must be arranged in an array with a large number of different sensors to achieve high-resolution 3D imaging. Furthermore, their transmission and reception times must be synchronized, which is technically very challenging. Therefore, it is advantageous for individual radar sensors to be as small, simple, flexible, fault-tolerant, robust, and inexpensive as possible. To achieve this, the radar sensors themselves must contain as little electronics as possible, and digital data processing must be decentralized within a central control unit.

[0044] Conventional mass-produced radar systems have an angular separability of 10° to 4° in azimuth. The angular separability in elevation is often even lower, making imaging methods unusable for radar data. Current LiDAR systems have an angular separability of 0.1°, which is unachievable with current radar systems.

[0045] Current radar sensors installed in vehicles typically have dimensions of 10 x 10 centimeters. Consequently, the maximum angular resolution achieved is approximately 2°, allowing only 2D environmental perception. For vehicles, current radar sensors have too large a spatial dimension with a small aperture, resulting in too low a resolution. This resolution does not allow for adequate environmental perception for autonomous driving. Installing multiple sensors requires their time synchronization, which is technically challenging and costly. Nanoradars have dimensions in the 5 x 5 centimeter range and, due to their compact design, can be more easily integrated into vehicles. Nanoradars have the same drawbacks. Furthermore, their range is currently limited to approximately 45 meters, which is too short, particularly for urban environments. Synthetic Aperture Radar (SAR) methods can increase resolution to the centimeter range. SAR methods only work perpendicular to the direction of travel. Predictions along or against the direction of travel are not possible with this method. Furthermore, the data processing required after the measurement is computationally intensive.

[0046] The installation of multiple electronic components within the sensors increases their size and cost, thus preventing the use of multiple sensors. Furthermore, time synchronization of the sensors is technically challenging. While aperture is achieved through distributed antennas and subsequent decentralized digital data processing within a central control unit, the electrical transmission of transmit and receive signals is problematic due to losses reaching several decibels.

[0047] Furthermore, multiple individual sensors must be used. The large physical dimensions of the sensors preclude concealed installation on the vehicle, so the sensors remain visible. The use of multiple individual sensors requires a relatively high level of effort to synchronize the individual sensors. Data merging is also complex and error-prone, as there is no central data acquisition; instead, each individual sensor acquires and forwards its own data. This results in high costs.

[0048] In contrast, the antenna device according to the present invention offers numerous advantages over the prior art. Overall, it is more cost-effective than known solutions. The placement of the radar device in the composite window pane allows for high manufacturing precision, as composite window panes are relatively rigid compared to sheet materials. This allows for simple integration of the antenna device into the vehicle. Manufacturing is accomplished using mature, well-developed technologies suitable for mass production. A simple design is possible. The number of individual sensors can be reduced, simplifying calibration. Concealed installation is possible. The device's large surface area allows for a very high angular separability of <= 0.1° for the radar.

[0049] Overall, this example shows how, by means of the present invention, a radar antenna unit can be provided in a window pane of a vehicle.

[0050] Reference Signs List

[0051] 1 Radar antenna device

[0052] 2 Composite window glass

[0053] 3. First layer of glass

[0054] 4. Second layer of glass

[0055] 5 antenna units

[0056] 6 radar beams

[0057] 7. Synthetic resin

[0058] 8Electric drive signal

[0059] 9Electric echo signal

[0060] 10 holes

[0061] 11 connection units

[0062] 12 amplifier units

[0063] 13 radar devices

[0064] 14 Optical drive signal

[0065] 15 optical echo signal

[0066] 16 coupling elements

[0067] 17 Photoconductor

[0068] 18-conductor line

[0069] 19 films

[0070] 20 vehicles

Claims

1. A radar antenna device (1) for a vehicle (20), the radar antenna device comprising: - composite window panes (2), at least one radar device (13) which is configured to transmit and / or receive radar beams (6), wherein: at least one radar device (13) having a corresponding antenna unit (5) and a corresponding amplifier unit (12), - the amplifier unit (12) is configured to provide an electrical drive signal (8) to the antenna unit (5) and / or to receive an electrical echo signal (9) from the antenna unit (5), It is characterized by: - the antenna unit (5) is arranged in the composite pane (2), - the amplifier unit (12) is arranged on the surface of the composite pane (2), The antenna unit (5) and the amplifier unit (12) are spatially separated from one another and are electrically conductively connected to one another via a connecting element (11) arranged in the composite pane; wherein the composite pane (2) has at least two glass layers, wherein the antenna unit (5) is arranged between the glass layers; and the at least two glass layers are connected to one another via a synthetic resin, wherein the antenna unit is incorporated into the synthetic resin arranged between the two glass layers.

2. The radar antenna device (1) according to claim 1, characterized in that The connecting element (11) is arranged in a hole in the composite pane (2).

3. The radar antenna device (1) according to claim 1, characterized in that The connecting element (11) is arranged perpendicular to the antenna unit (5).

4. The radar antenna device (1) according to claim 1, characterized in that The composite pane (2) has at least one film layer (19), wherein the antenna unit (5) is printed onto the film layer (19).

5. The radar antenna device (1) according to claim 1, characterized in that At least one of the glass layers (3), (4) is coated with an antenna unit (5).

6. The radar antenna device (1) according to claim 1, characterized in that The composite pane (2) has at least one optical waveguide (17), wherein the at least one optical waveguide (17) is connected to an amplifier unit (12) via an optical coupling element (16).

7. The radar antenna device (1) according to claim 1, characterized in that At least one of the glass layers (3), (4) has a metal conductor track (18) which is in electrical contact with the amplifier unit (12).

8. A vehicle (20) having a radar antenna arrangement (1) according to any one of the preceding claims.

9. A method for producing a radar antenna arrangement (1) for a vehicle (20), the radar antenna arrangement (1) comprising: - composite window panes (2), at least one radar device (13) configured to transmit and / or receive radar beams (6), wherein: at least one radar device (13) having a corresponding antenna unit (5) and a corresponding amplifier unit (12), - the amplifier unit (12) is configured to provide an electrical drive signal (8) to the antenna unit (5) and / or to receive an electrical echo signal (9) from the antenna unit (5), It is characterized by: - the antenna unit (5) is arranged in the composite pane (2), - the connecting element (11) is arranged in the composite pane (2), - the amplifier unit (12) is arranged on a surface of the composite pane (2), and - the antenna unit (5) and the amplifier unit (12) are electrically conductively connected to one another via a connecting element (11) arranged in the composite pane (2), The composite window pane (2) has at least two glass layers, wherein the antenna unit (5) is arranged between the glass layers; the at least two glass layers are connected to each other by synthetic resin, wherein the antenna unit is added to the synthetic resin arranged between the two glass layers.

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