Radar system

Abstract

A radar system (1) comprising an electronic component (2) for transmitting and / or receiving radar signals and an antenna element (3), wherein the antenna element (3) is configured as a plastic body into which a channel (4) having a metallized channel wall is introduced, the channel (4) forming a hollow conductor, and wherein a heat conduction element (5) is introduced into the antenna element (3).

Description

Technical Field

[0001] The present invention relates to a radar system including an electronic component that transmits and / or receives a radar signal and an antenna element, wherein the antenna element is formed as a plastic body into which a channel having a metallized channel wall is introduced, and the channel forms a hollow conductor.

Background Art

[0002] This type of radar system is known, for example, from US Patent Application Publication No. 2021 / 0183797. Radar systems of the type mentioned at the beginning are often used in motor vehicles, where they form components of driver assistance systems. For this purpose, the radar system detects the surroundings and enables at least one information notification to the driver in the form of an automatic reaction of the motor vehicle or, in particular, an alarm based on the detected data. Thereby, on the one hand, it becomes possible for the driver to control the vehicle speed to the speed set by the driver when the traffic situation permits, and at that time, the speed is automatically adapted to the traffic situation. In an emergency situation caused, for example, by an unexpected lane change of another vehicle detected by the radar system, automatic emergency braking can be triggered. In driver assistance systems and autonomous driving systems, the radar system is often combined with other sensors, such as radar sensors and camera sensors. The radar system has the advantage that the system operates reliably even when weather conditions are poor compared to other systems. Furthermore, in addition to detecting the distance to the detected vehicle and object, the relative speed to other vehicles can also be determined using the Doppler effect.

[0003] In a radar system, the antenna element forms a central element that critically affects the functionality of the radar system. In this case, it is known to form the antenna element from a plastic body consisting of one or more members, and channels are introduced into the antenna element, where the channel walls of the channels are configured to be conductive and the channels form a hollow body. The antenna element is operatively connected to electronic components in order to transmit and / or receive radar signals in this case.

[0004] The electronic components are, in most cases, microchips in the form of high-frequency chips arranged on a substrate. Here, it becomes a problem that significant heat dissipation occurs during the operation of the radar system, which is caused in particular by the requirement to form electromagnetic waves in a spectrum that is common for radar waves and has a sufficient range. The heat dissipation can be on the order of several watts depending on the configuration of the radar system, which occurs in particular when a radar system with a high heat load is compactly configured in a small space. In this case, the antenna element formed from plastic is only suitable to a limited extent for dissipating heat from the system in a proper manner because of its low thermal conductivity.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem underlying the present invention is to provide a radar system having improved thermal characteristics.

Means for Solving the Problems

[0006] The above problems are solved by the features of claim 1. Each dependent claim relates to an advantageous configuration.

[0007] The radar system according to the present invention includes an electronic component that transmits and / or receives a radar signal and an antenna element, and the antenna element is formed from a plastic body into which a channel having a channel wall configured to have conductivity is introduced. The channel forms a hollow conductor, and a heat conduction element is introduced into the antenna element.

[0008] According to the present invention, the antenna element has not only electromagnetic characteristics but also thermal characteristics, and heat can be transported through or from the antenna element. For example, the antenna element can release the heat introduced through the heat conduction element during manufacturing. Thereby, during manufacturing, on the one hand, a higher heat supply is possible, and on the other hand, the cooling time can be shortened. Furthermore, a compact radar system that is robust and operable over a long period can be configured. Due to the improved thermal characteristics of the antenna element, the temperature inside the antenna element is homogenized. Furthermore, the heat dissipation of the chip that transmits and receives radar radiation is also improved, thereby improving the measurement accuracy and transmission output of the radar system.

[0009] In the case of an antenna element composed of a plurality of members, the individual elements are often interconnected by a soldering process. In this case, heat supply is generally performed through the air flow taken in on both sides of the antenna element. The heat conduction element can improve the transport of hot air and can transport heat well into the element. Thereby, the bonding process can be accelerated, and at the same time, a soldered connection having improved quality can be obtained.

[0010] The heat conduction element may have recesses and / or through-holes introduced into the plastic body. Here, the recesses and / or through-holes are introduced into the plastic body independently of the channels forming the hollow conductor. As the plastic for the antenna element, in particular, heat-resistant polymers such as polyphenylene sulfide (PPS), polyetherimide (PEI), polyphenylene ether (PPE), polyamide (PA), liquid crystal polymer (LCP), polycarbonate (PC), polyphthalamide (PPA), polyetheretherketone (PEEK) or mixtures of the aforementioned polymers are conceivable.

[0011] Preferably, in the antenna element, in the area assigned to the microchip or the corresponding substrate area, there are no recesses and / or through-holes.

[0012] The thermal conductivity can be improved by coating the recesses and / or through-holes with a thermally conductive material. Advantageous materials for the coating are metals such as nickel, chromium, aluminum, copper, tin, zinc, silver or gold. These materials are also suitable for forming a conductive channel wall. The metal coating may be single-layer or multi-layer. Through the coating of the recesses and / or through-holes, heat conduction parallel to the material of the antenna element is performed, thereby improving the overall heat conduction. A typical thermal conductivity coefficient for plastic is, for example, about 0.3 W / m×K, and a typical thermal conductivity coefficient for copper is about 300 W / m×K.

[0013] The deposition of the metal coating can be carried out, in particular, by an electrolytic plating coating.

[0014] For example, a ceramic coating based on aluminum oxide is also possible. The ceramic coating can be deposited by a vacuum process.

[0015] The layer thickness of the coating is preferably 0.5 μm to 40 μm. Such a coating is low-cost and has good thermal conductivity.

[0016] Here, the recess can be formed, for example, in the form of a blind hole or a through hole. In this case, the recess can be formed circularly. However, particularly preferably, the recess or the through hole has a shape different from a circle. In this case, advantageously, the peripheral surface of the recess or the through hole is enlarged, thereby further increasing the thermal conductivity. This is particularly the case when the walls of the recess and / or the through hole are coated with a thermally conductive material. For example, the recess or the through hole may be formed in a clover shape as viewed in plan view. In order to improve the cooling capacity, the recess and / or the through hole preferably do not accommodate an object, particularly a holding means such as a screw and the like.

[0017] The recess and / or the through hole can form a channel. In this case, the recess protrudes into the plastic body or, in the case of the through hole, the through hole penetrates the plastic body. Thereby, heat can be released from the radar system through the plastic body, or heat can be transferred to another component of the radar system through the plastic body.

[0018] The heat flow through the antenna element increases as the number of recesses and / or through holes per unit area increases. Preferably, the unit area here relates to the surface of the antenna element facing the electronic component. Here, it has been found to be advantageous that 10 to 50 recesses and / or through holes are provided per 1 cm 2 of the surface facing the electronic component. Good heat flow can already be obtained from 3 or more recesses and / or through holes per 1 cm 2 . The recesses and through holes may have various geometric shapes, and this geometric shape and particularly the surface used for heat transfer affect heat transfer. In particular, the recess can be arranged in the region of the surface facing the electronic component. The through holes are preferably formed so that these through holes penetrate the antenna element.

[0019] Depending on the configuration of the recess and / or through-hole, when the recess or through-hole is formed in an elongated shape and particularly has a length exceeding 10 mm, within 1 cm of the surface facing the electronic component 2 it may be sufficient to provide 3 to 15 recesses or through-holes per centimeter. In the case of a meander structure, 1 to 10 per centimeter 2 per centimeter may be sufficient. The meander structure is particularly advantageous in the recesses near the surface. Overall, with the configuration here, good heat conduction through the antenna element occurs particularly during manufacturing and the associated bonding process. At the same time, the functionality of the antenna element is not impaired.

[0020] The heat conduction element can have recesses in the form of surface structuring parts. For example, surface structuring parts in the form of ribs or grooves can be introduced onto the surface of the plastic body, where the surface structure enlarges the surface of the plastic body, thereby further improving the heat conductivity. In this case, in particular, it is possible to introduce surface structuring parts into areas not related to the channels forming the hollow conductors in the plastic body. Within 1 cm of the surface facing the electronic component 2 when 3 to 15 structures are provided in the form of ribs or grooves per centimeter, advantageous heat dissipation through such surface structures is achieved. This is particularly the case when the structures are formed in an elongated shape and have a length exceeding 10 mm. In the case of a meander structure, 1 to 10 2 recesses per centimeter may be sufficient.

[0021] A heat conductor can also be embedded in the antenna element. In this case, the heat conductor has a higher thermal conductivity coefficient than the material of the plastic body. Thereby, heat can be transported to the outside particularly quickly and effectively through the heat conductor.

[0022] The heat conductor may be made of a metallic material. In particular in this context, the heat conductor can be formed as a molded part in the form of a cylindrical element, such as a sleeve or a wire. The heat conductor can also be formed in the form of a thin metal sheet. As a material for the heat conductor, in particular, a thermally conductive material made of a metallic material such as copper or aluminum is also conceivable.

[0023] The heat conductor may be made of a thermally conductive plastic. The thermal conductivity here is configured to be higher than the thermal conductivity of the material of the plastic body. In particular in this context, the heat conductor can be formed in the form of a flexible conductor path or from a pre-injection molded part. These have a lower thermal conductivity compared to heat conductors made of metallic materials, but the advantage is that heat conductors made of plastic can be realized in complex geometries. This is particularly advantageous in relation to complex hollow conductor structures. Preferably, the thermally conductive plastic has a thermal conductivity of at least 1 W / m×K.

[0024] The antenna element can also be formed in multiple layers. In this configuration, channels with particularly complex structures can be formed inside the plastic body and / or heat conducting elements can be arranged. Furthermore, it is also possible for each layer of the multi-layer antenna element to have different heat conduction characteristics. In particular in this context, it is advantageous if the layer facing the component or the substrate has a higher thermal conductivity than the other layers. For this purpose, the layer facing the component or the substrate can have a relatively thick coating, in particular a relatively thick metal coating.

[0025] The heat conducting element can have a deposited, for example printed, structure. For example, a thermally conductive material can be printed or adhered to the outer surface of the plastic body.

[0026] The antenna element can be covered by a radome. The radome protects the antenna element from external influences. The radome can form a structural unit together with the antenna element. In this configuration, the hollow conductor is closed on the emission side of the electromagnetic radiation, and the guiding of the electromagnetic radiation is performed by appropriately changing the coating.

[0027] Hereinafter, several configurations of the radar system according to the present invention will be described in detail with reference to the drawings. The following are schematically shown in the drawings.

Brief Description of the Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0029] The drawings show a radar system 1 which is a component of a driver assistance system for a vehicle. The radar system 1 includes an electronic component 2 that transmits and / or receives radar signals, and an antenna element 3 disposed on the electronic component 2. The component 2 is formed in the form of an integrated circuit and is disposed on a substrate 6. The antenna element 3 is connected to the component 2 by material bonding via an adhesive connection portion.

[0030] In an alternative configuration, the electronic component 2 is disposed on one main surface of the substrate 6, and the antenna element 3 is disposed on the other main surface. In this case, the substrate 6 is configured to transmit electromagnetic radiation between the component 2 and the antenna element 3.

[0031] The antenna element 3 is formed as a plastic body made of polyether ether ketone (PEEK). Here, the plastic body forming the antenna element 3 is formed in multiple layers and is formed from a plurality of plates laminated on top of each other. A plurality of channels 4 having metallized channel walls are introduced into the plastic body, and the channels 4 form a hollow conductor. The hollow conductor is operatively connected to the transceiver unit of the electronic component 2. The antenna element is covered by a radome.

[0032] A heat conduction element 5 is introduced into the antenna element 3. In this configuration, the heat conduction element 5 has recesses and through-holes. The recesses and through-holes form channels. In this case, the recesses are formed such that a surface structuring portion is formed on the side facing the component 2. A heat conductor made of a metal material, aluminum in this configuration, is embedded in the recesses. In an alternative configuration, the heat conductor is formed from a thermally conductive plastic. In another alternative configuration, the heat conduction element 5 has a printed structure.

[0033] FIG. 1 shows a cross-sectional view of the radar system 1 described above. FIG. 2 shows a perspective view of the antenna element 3 viewed obliquely from above, and FIG. 3 shows a perspective view of the antenna element 3 having the heat conduction element 5 in the form of meandering through-holes and recesses viewed obliquely from below. The walls of the recesses and through-holes are coated with a thermally conductive material.

[0034] FIG. 4 shows a plan view of the configuration of the antenna element 3 in which the heat conduction element 5 is formed in the form of a through-hole penetrating the antenna element 3. The cross-sectional shape of the through-hole is clover-shaped in this configuration. In this configuration, the area of the channel wall is larger than the cross-sectional area of the recess representing the required space of the through-hole, thus improving heat conduction.

[0035] The channel wall is provided with a coating made of a metal material, which is aluminum in this configuration. The layer thickness of the coating is 20 μm. In this configuration, 24 recesses are introduced per 1 cm of the surface of the antenna element facing the electronic component 2. 2 around.

[0036] Fig. 5 shows a graph of simulation calculations that can be seen to show that the heat flux increases as the number of through-holes increases. The number of through-holes from 0 to 12 is plotted on the horizontal axis, and the heat flux at 40 K, 0 W to 3 W is plotted on the vertical axis. The calculations here are based on introducing elongated through-holes with a length of 23 mm and a width of 1.2 mm into a cube made of polyamide with a side length of 25 mm. A gold coating with a layer thickness of 10 μm is provided on the surface of the cube. A temperature difference that generates a heat flux in the same direction is formed in the direction of the through-hole.

Claims

1. A radar system (1), comprising an electronic component (2) for transmitting and / or receiving a radar signal and an antenna element (3), wherein the antenna element (3) is configured as a plastic body into which a channel (4) having a metallized channel wall is introduced, and the channel (4) forms a hollow conductor, in the radar system (1). The radar system (1), characterized in that a heat conducting element (5) is introduced into the antenna element (3).

2. The radar system according to claim 1, wherein the heat conducting element (5) has recesses and / or through holes.

3. The radar system according to claim 2, wherein the recesses and / or the through holes form a channel.

4. The radar system according to claim 2 or 3, wherein the recesses and / or the through holes have a heat conductive coating.

5. One cm of the surface facing the electronic component (2) ２ The radar system according to any one of claims 2 to 4, wherein one to 50, particularly three to 15, recesses and / or through holes are provided per square centimeter of the surface facing the electronic component (2).

6. The radar system according to claim 4 or 5, wherein the coating contains a metallic material.

7. The radar system according to any one of claims 4 to 6, wherein the layer thickness of the coating is 0.5 μm to 40 μm.

8. The radar system according to any one of claims 4 to 7, wherein the coating is configured as an electroplated coating.

9. The radar system according to any one of claims 1 to 8, wherein the heat conducting element (5) has a surface structuring.

10. The radar system according to any one of claims 1 to 9, wherein the heat conducting element (5) includes a heat conductor embedded in the antenna element (3).

11. The radar system according to claim 10, wherein the heat conductor is made of a metallic material.

12. The radar system according to claim 10 or 11, wherein the heat conductor is formed of a heat conductive plastic.

13. The radar system according to any one of claims 1 to 12, wherein the antenna element (3) is formed in multiple layers.

14. The radar system according to claim 13, wherein the layer assigned to the component (2) has a higher thermal conductivity than the other layers.

15. The radar system according to any one of claims 1 to 14, wherein the heat conducting element (5) has a printed structure.

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