Radar sensor

Abstract

The invention relates to a radar sensor comprising a waveguide antenna (7), a radome (1), a housing (3) on which the radome (1) is mounted, and a printed circuit board (4) in which the waveguide antenna (7) is arranged. The waveguide antenna (7) and the radome (1) are interlockingly connected to one another.

Description

[0001] Description

[0002] title

[0003] radar sensor

[0004] The present invention relates to a radar sensor comprising a waveguide antenna and a radome. The radar sensor can be used, for example, in the automotive industry.

[0005] State of the art

[0006] Waveguide antennas, which have a waveguide structure for transmitting and receiving radar waves, have recently been frequently used in radar sensors. The waveguide antennas are connected to circuit boards and fed with radar waves via electrical components located on the circuit board. Traditionally, waveguide antennas are attached directly to the circuit board. To protect the radar sensor and the waveguide antenna from external influences, the radar sensor has a radome. The radome is positioned in the radiation direction, typically on the side of the antenna opposite the circuit board, and is permeable to radar waves. The radome is usually attached to a radar sensor housing, to which the circuit board is also attached.

[0007] Disclosure of the invention

[0008] A radar sensor is proposed that has a waveguide antenna and a radome, wherein the radome and the waveguide antenna are positively connected to each other. The waveguide antenna and the radome are therefore firmly connected to each other before installation on the radar sensor. In other words, the waveguide antenna is integrated into the radome. This allows the waveguide antenna and the radome to be manufactured as an assembly in advance and already adapted to each other, which simplifies production. Because the radome and the waveguide antenna are firmly connected to each other, the distance between the radiating surface of the waveguide antenna and the radome, which is important for the performance of the radar sensor, does not change even in the event of vibration or deformation.

[0009] The assembly is finally mounted on a radar sensor housing. The radome is preferably attached to the housing using a laser welding process. Distance measurements previously determined for the production of the radar sensor and the radome-waveguide antenna assembly can be used as input parameters for the laser welding process. This allows the distance between the waveguide antenna and the circuit board to be precisely adjusted. During assembly, the waveguide antenna is positioned by the circuit board by positioning elements of the waveguide antenna engaging corresponding guide elements in the circuit board. For example, the positioning elements are designed as pins extending from the waveguide antenna, and the guide elements are openings in the circuit board. The pins engage in the corresponding openings for guidance.

[0010] Since the waveguide antenna is already firmly attached to the radome, further fastening of the waveguide antenna to the circuit board is unnecessary. The radome-waveguide antenna assembly is held in place solely by the radome's attachment to the housing. This allows for fewer fastening elements and / or guide elements to be provided on the circuit board, thus reducing the space required on the circuit board. In particular, two guide elements on the circuit board are sufficient for fastening the assembly. A lateral positional misalignment between the launchers on the circuit board and the ports of the waveguide antennas can be compensated for using the positioning and / or guide elements via a short tolerance chain.

[0011] By mounting the antenna via the housing, the waveguide antenna and the circuit board are decoupled from each other. The forces acting on the waveguide antenna are not absorbed by the circuit board, resulting in less stress on the connection between the circuit board and the housing, especially when the radar sensor is subjected to vibration.

[0012] For the form-fitting connection technology, the radome preferably has

[0013] Pins that extend through the waveguide antenna, preferably to the opposite side, and are connected to the waveguide antenna. The pins enable a simple, positive connection.

[0014] A hot-staking process can be used as a preferred form-fitting connection technique. During hot-staking, plastic mandrels are melted using heat and then deformed under pressure. The aforementioned radome studs are preferably used as plastic domes, which then function as hot-staking studs. The radome's hot-staking studs extend through the waveguide antenna and are then melted and deformed on the opposite side so that they rest against the waveguide antenna. The waveguide antenna preferably has a recess into which the deformed hot-staking stud engages.

[0015] Optionally, the waveguide antenna has at least one projection extending from the main body in which the waveguides are formed. The positive connection of the radome to the waveguide antenna takes place at this at least one projection. Preferably, the pins, in particular the hot-staking pins, can extend through this at least one projection and engage into it on the opposite side. Consequently, the positive connection is realized outside the main body of the waveguide antenna, whereby no space is required on the main body for the positive connection. As a result, smaller overall designs can be realized.

[0016] Furthermore, a method for manufacturing a radar sensor is proposed. Initially, a waveguide antenna and a radome are provided. The shape and size of the waveguide antenna and the radome are adapted to each other, as well as to a housing and a circuit board to which they will later be connected. The distances between the waveguide antenna and the circuit board are also determined. The waveguides are already formed accordingly in the waveguide antenna. The radome is then positively connected to the waveguide antenna to form a radome-waveguide antenna assembly. As described above, a hot-staking process is used as the preferred positive-locking connection technique. These steps are performed before assembly on the housing and circuit board. This allows the radome-waveguide antenna assembly to be manufactured and delivered in advance, for example, by a supplier.Finally, during assembly, the radome-waveguide antenna assembly is mounted to the housing. The laser welding process described above is preferably used to connect the radome to the housing.

[0017] Overall, the radar sensor can be manufactured cost-effectively using standardized processes for series production in high quantities.

[0018] Short description of the drawings

[0019] Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description.

[0020] Figure 1 shows a cross section through a radar sensor according to the invention according to a first embodiment.

[0021] Figure 2 shows a cross section through a radar sensor according to the invention according to a second embodiment.

[0022] Figures 3 a - d show top views of a waveguide antenna with hot-staking pins of a radome in different arrangements.

[0023] Embodiments of the invention

[0024] Figure 1 shows a first embodiment of the radar sensor according to the invention. The radar sensor comprises a waveguide antenna 7, a radome 1, a housing 3, and a circuit board 4. The circuit board 4 has a chip 6 with a launcher that generates radar waves. The circuit board 4 is attached directly to the housing 3. According to the invention, the waveguide antenna 7 is positively connected to the radome 1. For this purpose, the radome 1 has hot-staking pins 2, two of which are shown in Figure 1. During manufacture, the hot-staking pins 2 are inserted into openings in the waveguide antenna 7 and extend through the openings to the opposite side—referred to here as the rear side and opposite the radiating surface. On the rear side, the waveguide antenna 7 in this exemplary embodiment has a recess 8 at the location of each hot-staking pin 2, into which a head of the hot-staking pin 8 projects.During the hot-staking process, the head of the hot-staking pin 2 is pressed against the back side using heat and pressure, thereby deforming it. This "squeezes" the waveguide antenna 7 between the hot-staking pin 2 and creates a positive connection. This creates an integral radome-waveguide antenna assembly. During the hot-staking process, the distance D between the radiating surface of the waveguide antenna 7 and the radome 1, which is important for the performance of the radar sensor, is determined using a tool-specific dimension. Thanks to the positive connection, the distance D remains constant throughout the service life of the radar sensor and is protected from vibrations and other deformations.

[0025] The waveguide antenna 7 also has peg-shaped positioning elements 5 on its rear side. During assembly of the radome 1 and the waveguide antenna 7 to the housing 3 and the circuit board 4, the positioning elements 5 are pre-centered through openings in the circuit board 4 in a pre-assembly step. The positioning elements 5 ensure the lateral position of the waveguide antenna 7 with respect to the launcher on the chip 6 during pre-assembly, laser welding, and the final installation of the radar sensor. During assembly, the radome 1 is connected to the housing 3 using a laser welding process. This adjusts the distance A between the waveguide antenna 7 and the circuit board 4, which is important for correct coupling and decoupling of the radar waves.To adjust the distance A, the distance B between the connection point of the radome 1 and the circuit board 4, as well as the distance C between the connection point of the radome 1 and the back of the waveguide antenna 7, are determined. The distance C is determined when the radome 1 and the waveguide antenna 7 are connected and then transmitted to a production station of the laser welding process using a data matrix code or another data transmission method. Before laser welding, the distance B is then calculated from the sum of the distance C and the previously determined distance A, and the laser welding process is carried out using the calculated distance B.

[0026] Figure 2 shows a second embodiment of the radar sensor according to the invention. Identical components are identified by the same reference numerals, and reference is made to the above description. The second embodiment differs from the first embodiment only in that the waveguide antenna 7 has projections 9, and the hot-staking pins 2 extend through these projections 9. As a result, the hot-staking pins 2 are located outside the main body of the waveguide antenna 7, so that the main body can be made smaller than in the first embodiment. During the hot-staking process, heat and pressure are used to press the head of the hot-staking pin 2 against the back of the projection 9, thereby deforming it. The waveguide antenna 7 is "squeezed" by the hot-staking pins 2, creating a positive connection.

[0027] Figures 3 a to d show plan views of the waveguide antenna 7, in which the radome 1 is not shown for reasons of clarity, and show various exemplary arrangements of the hot-staking pins 2 of the radome 1 on the waveguide antenna 7. These arrangements are to be understood as examples only, and different arrangements and a different number of hot-staking pins 2 can be used depending on the actual application and the available installation space. In Figures 3 a and b, according to the first embodiment, the description of which is referred to in connection with Figure 1, the hot-staking pins 2 are connected to the main body of the waveguide antenna 7, in which the waveguides are also formed. Figure 3 a shows two hot-staking pins 2 on opposite sides of the waveguide antenna 7, which are sufficient for a stable connection of the waveguide antenna 7 to the radome 1.Figure 3b shows three hot-staking pins 2 that form a triangle, further increasing stability. In Figures 3c and d, according to the second embodiment, the description of which is referred to in connection with Figure 2, a projection 9 is formed on the waveguide antenna 7 for each hot-staking pin 2, and the respective hot-staking pin 2 is connected to the corresponding projection 9. Figure 3c shows two projections 9 and two hot-staking pins 2 on opposite sides of the waveguide antenna 7, and Figure 3d shows three projections 9 and three hot-staking pins 2 that form a triangle.

Claims

AMENDED CLAIMS received by the International Bureau on 5 July 2023 (05.07.2023) Radar sensor comprising a waveguide antenna (7), a radome (1), a housing (3) to which the radome (1) is attached, and a circuit board (4) in which the waveguide antenna (7) is positioned, wherein the waveguide antenna (7) and the radome (1) are positively connected to one another, characterized in that the radome (1) has pins (2) extending through and connected to the waveguide antenna (7). Radar sensor according to one of claim 1, characterized in that the positive connection is realized by a hot-stitching process. Radar sensor according to claim 1 or 2, characterized in that the waveguide antenna (7) has at least one projection (9) and the positive connection is realized on the at least one projection (9). Method for manufacturing a radar sensor, characterized by the following steps: - Provide a waveguide antenna (7); - Provision of a radome (1); - positive locking connection of the radome (1) with the waveguide antenna (7); - Mounting the radome waveguide antenna assembly on a housing (3) of the radar sensor. Method according to claim 4, characterized in that the positive locking connection is effected by a hot riveting process. AMENDED SHEET (ARTICLE 19)

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