JP7579358B2 - Radar Equipment - Google Patents

Description

The present invention relates to a radar device.

In recent years, radar devices have been developed as a sensing device to assist drivers in preventing automobile accidents and to realize autonomous driving. Radar devices emit high-frequency electromagnetic waves, typically millimeter waves, into the surrounding area, receive the electromagnetic waves reflected from targets, and perform signal processing to obtain information on the position and speed of the target. Using this information, it is possible to build a system that calculates the risk of collision between the target and the vehicle and issues an alarm.

Meanwhile, a camera device, which is one type of sensing device, requires ambient light or auxiliary light, but a radar device uses electromagnetic waves, so it is capable of detecting targets using only the radar device. Due to this characteristic, radar devices are particularly suitable for mounting in the corners and sides of vehicles. Furthermore, due to this application, there is a demand for radar devices to have a wide detection range for targets.

Figure 8 is a diagram showing an example of a radar device attached to a vehicle. In Figure 8, the upper side shows the front of the vehicle, and the lower side shows the rear of the vehicle. As shown in Figure 8, the radar device 1 is mounted on the side F of the vehicle 7. In order to enable the radar device 1 to function as an alarm system, if a specific direction is set as a direction in which the detection sensitivity of the radar device 1 is high, a part of the detection range E may overlap with the side F of the vehicle 7 and receive a reflected wave R from this side F. The target information from the reflected wave R from the vehicle 7 is unnecessary information for the alarm system, and if the intensity of this reflected wave R is high, it may not be possible to separate it from the original target information in signal processing, which raises concerns that the alarm function for targets that pose a collision risk to the vehicle 7 may not operate normally.

As a solution to this problem, for example, the technologies described in Patent Document 1 and Patent Document 2 have been proposed.

Patent document 1 discloses a technology in which a wall is formed from the inner surface of the radome surface toward the circuit board, thereby imparting directionality to the radar waves from the transmitting antenna section.

Furthermore, Patent Document 2 discloses a technology in which a radio wave absorbing material is attached onto the surface of the antenna substrate.

In Patent Documents 1 and 2, the above-mentioned technology is applied to suppress unnecessary reflected waves from the vehicle itself.

JP 2014-20846 A JP 2019-41224 A

The technology described in Patent Document 1 requires the formation of a wall on the inner surface of the radome, which necessitates changes to the radome molding die, resulting in significant costs.

In addition, the technology described in Patent Document 2 requires an additional process for attaching expensive radio wave absorbing material to the substrate, which increases the cost of the product.

The object of the present invention is to provide a radar device that can solve the above problems, suppress cost increases, and attenuate radio wave strength at a specific angle.

In order to achieve the above object, the present invention provides a radar device including a circuit board having a transmitting antenna unit that transmits electromagnetic waves, and a radome unit that covers the circuit board,
The radar device is an on-board radar mounted on a vehicle, and is mounted on the side of the vehicle extending from the front to the rear of the vehicle, and is attached at an angle to the side of the vehicle so that the surface of the circuit board carrying the transmitting antenna unit faces the rear outward of the vehicle, and the metal part is positioned on the circuit board closer to the vehicle than the transmitting antenna unit and reflects electromagnetic waves transmitted from the transmitting antenna unit.

The present invention makes it possible to provide a radar device that can attenuate radio wave strength at specific angles while suppressing increases in costs.

1 is a schematic cross-sectional view of a radar device according to a first embodiment of the present invention; FIG. 2 is a top view of the transmitting antenna section and the metal section in FIG. 1 . FIG. 4 is a diagram showing an example of a calculation result of the radiation power characteristic of an electromagnetic wave according to the first embodiment of the present invention. FIG. 11 is a top view of a transmitting antenna section and a metal section according to a second embodiment of the present invention. FIG. 11 is a diagram showing an example of a calculation result of the radiation power characteristic of an electromagnetic wave according to the second embodiment of the present invention. FIG. 11 is a top view of a transmitting antenna section and a metal section according to a third embodiment of the present invention. FIG. 11 is a diagram showing an example of a calculation result of the radiation power characteristic of an electromagnetic wave according to the third embodiment of the present invention. FIG. 1 is a diagram showing an example of a radar device mounted on a vehicle. FIG. 9 is an enlarged view of a radar device portion in FIG. 8 .

Below, the embodiments are explained using the drawings. Note that in this embodiment, only the parts related to the irradiation of electromagnetic waves that are relevant to the present invention are explained, and explanations of the monolithic microwave integrated circuit, receiving antenna, signal processing circuit, etc. that are necessary to operate as a radar device are omitted. The following embodiments are intended to explain the present invention, and can be implemented in other forms, and the present invention is not limited thereto.

Figure 1 is a schematic cross-sectional view of a radar device according to a first embodiment of the present invention, and Figure 2 is a top view of the transmitting antenna section and metal section in Figure 1. Figure 1 is a cross-sectional view taken along line I-I in Figure 2. Figure 9 is an enlarged view of the radar device portion in Figure 8.

The radar device 1 of the present invention is mounted, for example, on a vehicle and used as an on-vehicle radar. In the first embodiment, the radar device 1 is mounted on the side of the vehicle 7 at an angle so that the surface of the circuit board 3 on which the transmitting antenna unit 4 is mounted faces the rear outward of the vehicle 7, with the radar wave transmission direction being 0 degrees, the side of the vehicle 7 from the radar wave transmission direction being - degrees, and the outside of the vehicle 7 being + degrees. When this radar device 1 is used as an on-vehicle radar, it is used to detect other vehicles and the like that are present in blind spots that cannot be seen visually, by the left and right door mirrors, or by the rearview mirror.

In Figures 1 and 2, the radar device 1 is composed of a radome section 2 having a U-shaped cross section, a comb-tooth shaped transmitting antenna section 4, a metal section 5, and a circuit board 3 having the transmitting antenna section 4 and the metal section 5. The transmitting antenna section 4 and the metal section 5 are formed, for example, by printing a metal member on the circuit board 3.

The radome portion 2 is disposed so as to cover the circuit board 3, and has the function of protecting the circuit board 3 from the surrounding environment. The radome portion 2 is made of any of polycarbonate, syndiotactic polystyrene, polypropylene, ABS resin, etc. The transmitting antenna portion 4 and the metal portion 5 are configured to have the same thickness (height) on the circuit board 3. In the first embodiment, by making the thickness (height) of the transmitting antenna portion 4 and the metal portion 5 the same, for example, when the transmitting antenna portion 4 and the metal portion 5 are formed on the circuit board 3 by printing, the transmitting antenna portion 4 and the metal portion 5 can be printed and formed at the same time, which shortens the manufacturing process and reduces manufacturing costs.

The transmitting antenna section 4 has the function of radiating high-frequency electromagnetic waves W, such as millimeter waves, to the surroundings. The transmitting antenna section 4 is made of, for example, steel plate, galvanized steel plate, zinc spray coating, copper plate, copper foil, aluminum plate, aluminum foil, etc. The transmitting antenna section 4 is formed with protrusions 4a and 4b protruding from the surface of the transmitting antenna section 4, with the protrusion 4a side facing the metal section 5. Multiple protrusions 4a and 4b are formed on each surface.

The metal part 5 is an independent structure that is not connected to other circuits such as the GND wiring in the circuit board 3, and is formed adjacent to and at the same time as the transmitting antenna part 4. This metal part 5 has the function of re-reflecting the electromagnetic wave components of the electromagnetic waves W radiated from the transmitting antenna part 4 that are partially reflected by the surface 21 of the radome part 2. The metal part 5 is made of the same material as the transmitting antenna part 4, for example, steel plate, galvanized steel plate, zinc spray coating, copper plate, copper foil, aluminum plate, aluminum foil, etc. In the first embodiment, the manufacturing cost can be reduced by making the transmitting antenna part 4 and the metal part 5 out of the same material. In addition, the metal part 5 is arranged closer to the vehicle 7 than the transmitting antenna part 4.

By appropriately selecting the distance between the surface of the radome section 2 and the circuit board 3 and the shape of the metal section 5, among the electromagnetic waves W radiated from the transmitting antenna section 4, the electromagnetic wave component A that passes through the radome section 2 and the electromagnetic wave component B that is reflected by the surface 21 of the radome section 2 and further reflected again by the metal section 5 and passes through the radome section 2 are in an anti-phase relationship, and the electromagnetic wave components A and B interfere with each other and cancel each other out, making it possible to attenuate the radiation power of the electromagnetic wave in this direction. Since the electromagnetic wave component B is reflected by the surface 21 of the radome section 2 and the metal section 5, when it passes through the radome section 2, its phase lags behind that of the electromagnetic wave component A and it is in anti-phase with the electromagnetic wave component A. Since the metal section 5 is disposed closer to the vehicle 7 than the transmitting antenna section 4, the radiation power of the electromagnetic wave transmitted to the vehicle 7 side is attenuated, and the reflected wave from the side of the vehicle 7 can be suppressed.

In addition, the additional metal section 5 can be formed simultaneously with the transmitting antenna section 4, so the additional costs incurred by this method are extremely minimal.

In the first embodiment, the transmitting antenna part 4 and the metal part 5 are formed in a straight line when viewed from above and are arranged in parallel. The distance between the surface C of the transmitting antenna part 4 and the surface D of the metal part 5 is set to be equal to the thickness of the metal part 5.

Next, a calculation example of the radiation power characteristics of electromagnetic waves in the configuration of Fig. 2 will be described. Fig. 3 is a diagram showing an example of the calculation result of the radiation power characteristics of electromagnetic waves in Example 1 of the present invention. In Fig. 3, the solid line shows the case where there is no metal part 5, and the dashed line shows the case where there is a metal part 5.

In Figure 3, when the metal part 5 is installed, the radiated power is reduced in the angular region smaller than -30 degrees.

According to Example 1, by installing the metal part 5, the radiated power in a specified area can be reduced.

Furthermore, according to Example 1, by setting the direction in which the radiated power is attenuated toward the vehicle body, it is possible to relatively reduce the reflected electromagnetic waves from the vehicle body. This makes it possible to separate the original target information in the signal processing of the radar device, and allows the alarm function to operate normally. Furthermore, the additional metal section can be formed simultaneously with the transmitting antenna section, thereby suppressing the occurrence of additional costs.

Next, we will explain the second embodiment of the present invention. The same components as those in the first embodiment are given the same reference numerals, and detailed explanations of them will be omitted.

The difference between Example 2 and Example 1 is that multiple metal parts are provided. Figure 4 is a top view of the transmitting antenna part and metal parts according to Example 2 of the present invention, and Figure 5 is a diagram showing an example of a calculation result of the radiation power characteristics of electromagnetic waves according to Example 2 of the present invention.

In FIG. 4, the transmitting antenna section 4 is formed with protrusions 4a, 4b (antenna section protrusions) protruding from the surface of the transmitting antenna section 4, and the protrusion 4a side faces the metal section 5. A plurality of protrusions 4a, 4b are formed on each surface. The transmitting antenna section 4 is formed in a comb shape by the plurality of protrusions 4a, 4b. A metal section 51 is arranged at least in one location between adjacent protrusions 4a of the plurality of protrusions 4a. A plurality of metal sections 51 are provided, and each is arranged between adjacent protrusions 4a. By configuring in this manner, the installation space of the metal section 5 can be reduced, and the circuit board 3 can be made smaller. In the second embodiment, the circuit board 3 can be made smaller, which reduces manufacturing costs and expands the target and range in which the radar device can be mounted.

The radiation power characteristics of electromagnetic waves in the configuration of Figure 4 are as shown in Figure 5. In Figure 5, the solid line shows the case where there is no metal part 5, and the dashed line shows the case where there is a metal part 51.

In Figure 5, when the metal part 51 is installed, the radiated power is reduced in the angular region smaller than -15 degrees. This effect is greater than when the straight metal part 5 in Figure 2 is installed. Furthermore, in the angular region larger than 30 degrees, the effect of increasing the radiated power is also obtained.

According to the second embodiment, by disposing the metal part 51 between the multiple protrusions 4a formed in a comb-tooth shape of the transmitting antenna part 4, it is possible to reduce the radiated power in a predetermined area on the side where the metal part 51 is disposed. Also, according to the second embodiment, it is possible to increase the radiated power in a predetermined area on the side opposite to the side where the metal part 51 is disposed.

Next, we will explain the third embodiment of the present invention. The same components as those in the first embodiment are given the same reference numerals, and detailed explanations of them will be omitted.

Example 3 differs from Example 1 in that multiple protrusions are provided on the metal portion. Figure 6 is a top view of the transmitting antenna portion and metal portion according to Example 3 of the present invention, and Figure 7 is a diagram showing an example of a calculation result of the radiation power characteristics of electromagnetic waves according to Example 3 of the present invention.

6, the transmitting antenna section 4 has protrusions 4a and 4b protruding from the surface of the transmitting antenna section 4, and the protrusion 4a side faces the metal section 52. The transmitting antenna section 4 is formed in a comb-like shape. In addition, a plurality of protrusions 52a (metal section protrusions) are formed on the side of the metal section 52 facing the transmitting antenna section 4. The transmitting antenna section 4 side of the metal section 52 is formed in a comb-like shape. The plurality of protrusions 52a are arranged between adjacent protrusions 4a. In other words, the transmitting antenna section 4 and the metal section 52 are arranged so that their comb teeth mesh with each other. By configuring in this way, the installation space of the metal section 5 can be reduced and the circuit board 3 can be made smaller. In the third embodiment, the circuit board 3 can be made smaller, which reduces manufacturing costs and expands the target and range in which the radar device can be installed.

In Figure 7, the solid line indicates the case where there is no metal part 5, the dashed line indicates the case where there is a metal part 51 (Figure 4), and the dotted line indicates the case where there is a metal part 52 (Figure 6).

In Figure 7, when the metal part 52 is installed, the radiated power is smaller in the angle region smaller than -15 degrees. Furthermore, in the angle region smaller than -40 degrees, the radiated power is smaller than that of the configuration of Figure 4 (Example 2). Also, in the angle region larger than 30 degrees, the effect of increasing the radiated power compared to the configuration of Figure 4 (Example 2) is obtained.

According to the third embodiment, by disposing a plurality of comb-shaped protrusions 52a of the metal part 52 between a plurality of comb-shaped protrusions 4a of the transmitting antenna part 4, it is possible to reduce the radiated power of a predetermined area on the side where the metal part 52 is disposed. Also, according to the third embodiment, it is possible to increase the radiated power of a predetermined area on the side opposite to the side where the metal part 52 is disposed.

In Examples 1 to 3, a configuration in which the metal part is placed on the circuit board is shown, but the metal part is not limited to this placement. For example, it may be placed on a rib extending from the side of the radome part. Alternatively, a placement part may be provided on the circuit board 3, and the metal part may be placed on this placement part. The metal part may be placed within the space surrounded by the radome part.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. Therefore, the present invention can be embodied in various forms without departing from the concept and gist of the present invention.

1... radar device, 2... radome portion, 3... circuit board, 3... circuit board, 4... transmitting antenna portion, 4a, 4b... protrusion portion (antenna portion protrusion), 5, 51, 52... metal portion, 7... vehicle, 21... surface, 52a... multiple protrusion portions (metal portion protrusion)

Claims (5)

A radar device comprising a circuit board having a transmitting antenna section for transmitting electromagnetic waves, and a radome section for covering the circuit board,
a metal portion not connected to a circuit is provided within a space surrounded by the radome portion,
the radar device is an on-vehicle radar mounted on a vehicle, and is mounted on a side surface of the vehicle extending from the front to the rear of the vehicle, and is attached at an incline with respect to the side surface of the vehicle such that a surface of the circuit board on which the transmitting antenna unit is mounted faces toward the rear outside of the vehicle;
The metal portion is disposed on the circuit board closer to the vehicle than the transmitting antenna portion, and reflects electromagnetic waves transmitted from the transmitting antenna portion. In claim 1,
A radar device characterized in that the transmitting antenna section and the metal section are made of any one of a steel plate, a galvanized steel plate, a zinc-sprayed plate, a copper plate, a copper foil, an aluminum plate, and an aluminum foil. In claim 1,
A radar device, wherein the transmitting antenna section and the metal section have the same thickness. In claim 1,
A radar device, wherein the transmitting antenna section and the metal section are formed in a straight line and arranged in parallel. In claim 1,
The radar device is characterized in that the transmitting antenna portion has a plurality of protrusions protruding toward the metal portion, and the metal portion is disposed at at least one location between adjacent ones of the plurality of protrusions.

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