JP7304560B2 - radar equipment - Google Patents

Description

The present disclosure relates to radar equipment.

Radar devices that detect the position of an object in a non-contact manner using millimeter wave or microwave frequency bands are known. Radar devices of this type are installed, for example, at the four corners of a vehicle body, and are used for multidirectional monitoring applications such as forward monitoring, front side monitoring, or rear side monitoring.

In recent years, in this type of radar device, since the applications in the devices (for example, vehicles) to be mounted are diversified, the detection range is widened, that is, the side directivity of the device is enhanced. is required.

Ordinarily, an array antenna consisting of multiple antenna elements enhances directivity, but the wide-angle performance of an array antenna is limited by the directivity of the antenna elements, so there is a limit to improving the directivity of the side of the device. be.

For example, Patent Literature 1 discloses an adaptive array antenna including a plurality of patch antennas arranged in a flat area and a plurality of patch antennas arranged in an inclined area on a multilayer substrate. In this configuration, the side directivity is enhanced by the patch antenna arranged in the inclined area.

WO2017/047396

However, since it is necessary to polish the multilayer substrate in order to form the inclined region in the multilayer substrate, there arises a problem that it is difficult to manufacture the device. In addition, since the shape of the lens arranged in front of the antenna needs to match the shape of the multilayer substrate, there arises a problem that the manufacturing is further difficult.

An object of the present disclosure is to provide a radar device that is easy to manufacture and that can improve lateral directivity.

The radar device according to the present disclosure is
an antenna unit having a plurality of antenna elements configured by an endfire array antenna;
a circuit board on which the plurality of antenna elements are arranged side by side in a first direction;
with
At least some of the plurality of antenna elements are arranged in a second direction parallel to the substrate surface of the circuit board and orthogonal to the first direction, and in a direction inclined with respect to the first direction. arranged to radiate electromagnetic waves in a certain third direction ,
at least some of the plurality of antenna elements are arranged along the third direction; a second portion arranged along a fourth direction that is inclined with respect to the first direction;
A first reflector arranged opposite to the third direction with respect to the second portion of the antenna element and reflecting electromagnetic waves in the third direction,
The reflecting surface of the first reflecting portion has a stepped shape parallel to the second portion .

ADVANTAGE OF THE INVENTION According to this indication, it is easy to manufacture and can improve a side directivity.

1 is a diagram showing a vehicle equipped with a radar device according to an embodiment of the present disclosure; FIG. 1 is a plan view of a radar device according to an embodiment; FIG. 3 is an enlarged plan view of an antenna element portion in the radar device; FIG. It is a sectional side view in a radar apparatus. It is a figure which shows the relationship of the detection angle and gain in a radar apparatus. 3 is an enlarged plan view of an antenna element portion in the radar device; FIG. It is a figure for demonstrating an example of the effect of a radar apparatus. It is a figure for demonstrating an example of the effect of a radar apparatus. It is a figure for demonstrating an example of the effect of a radar apparatus. It is an enlarged plan view of the antenna element portion in the radar device according to the modification. It is an enlarged plan view of the antenna element portion in the radar device according to the modification. It is an enlarged plan view of the antenna element portion in the radar device according to the modification. It is an enlarged plan view of the antenna element portion in the radar device according to the modification.

Hereinafter, embodiments of the present disclosure will be described in detail based on the drawings. FIG. 1 is a diagram showing a vehicle C equipped with a radar device 100 according to an embodiment of the present disclosure. FIG. 2 is a plan view of the radar device 100 according to this embodiment.

As shown in FIG. 1, the radar device 100 transmits and receives millimeter waves or electromagnetic waves in a frequency band higher than the millimeter waves, for example, via a cover member B of a vehicle C or the like. The radar devices 100 are provided, for example, at the four corners of the vehicle body.

As shown in FIG. 2 , the radar device 100 has a housing (not shown), a circuit board 110 , an antenna section 120 and a lens 130 . In FIG. 2 and the like, a diagram of the radar device 100 viewed from the + side in the Z direction is shown.

An orthogonal coordinate system (X, Y, Z) is used to describe the structure of the radar device 100 of the present embodiment. A common orthogonal coordinate system (X, Y, Z) is used in the drawings to be described later.

A solid-line arrow F in FIG. 2 represents an electromagnetic wave transmitted by a transmitting antenna. A dotted arrow Fr represents a reflected wave from the target. 2, illustration of a structure for supporting the radar device 100 in the vehicle C is omitted.

The radar device 100 according to the present embodiment uses the antenna section 120 disposed in the + side end region of the circuit board 110 in the X direction to An electromagnetic wave is transmitted/received to/from the outside of the apparatus via the lens 130, with the direction inclined by the lens 130 (the first inclined direction described later) as the directivity direction. That is, in the radar device 100 according to the present embodiment, the circuit board 110 is arranged so that the extending direction of the board surface intersects (for example, is perpendicular to) the extending direction of the cover member B. .

With such a configuration, the radar device 100 according to the present embodiment prevents the reflected wave reflected by the cover member B from being multiple-reflected between the circuit board 110 and the like, causing interference with the reflected wave from the target, and , suppresses the reflected wave from entering the antenna section 120 as a looping wave.

The circuit board 110 is a board on which the antenna section 120, a signal processing IC, a connector, and the like are mounted. In the circuit board 110, the antenna section 120, the signal processing IC, the connector, etc. are mounted, and the wiring (see FIG. not shown) are patterned.

The circuit board 110 is arranged so that the board surface is parallel to the XY plane.

Although the material of the circuit board 110 is not particularly limited in the present disclosure, for example, a PCB (Printed Circuit Board) board can be used. Note that the circuit board 110 typically has a flat plate shape.

As shown in FIGS. 3A and 3B, the circuit board 110 has a surface layer member 111, an inner layer member 112, and a reflective member 113. As shown in FIGS. The surface member 111 is a conductor arranged on the surface of the circuit board 110 . A plurality of surface layer members 111 are arranged side by side in the Y direction so as to sandwich strip conductors 122 of a plurality of first elements 121A, which will be described later.

In addition, the X-direction end of one surface layer member 111 has a first end 111A and a second end 111B having a stepped shape.

The first end portion 111A is arranged in parallel with an extension element 123 of a first element 121A, which will be described later. The second end portion 111B is arranged at a position that protrudes in the X direction from the first end portion 111A, and is arranged in parallel with an extension element 123 of a second element 121B, which will be described later.

The inner layer member 112 is a conductor provided inside the circuit board 110 and is arranged on the negative side of the surface layer member 111 in the Z direction. The inner layer member 112 is connected to the ground.

The X-direction end of the inner layer member 112 has substantially the same shape as the X-direction end of the surface layer member 111 .

The surface layer member 111 and the inner layer member 112 are electrically connected by vias 114 . Thus, the X-direction first end portion 111A of the surface layer member 111 functions as a reflecting surface that reflects the electromagnetic waves radiated from the antenna portion 120 . The first end 111A corresponds to the "first reflector" of the present disclosure.

The reflecting member 113 is arranged inside the circuit board 110 on the negative side in the Z direction with respect to the inner layer member 112 . The reflecting member 113 is arranged in a range extending to the + side in the X direction from the end portions of the surface layer member 111 and the inner layer member 112 .

The reflecting member 113 has a function of reflecting the electromagnetic wave transmitted by the antenna unit 120 when the electromagnetic wave travels in the negative direction in the Z direction (see arrow F1 in FIG. 3B). The reflecting member 113 corresponds to the "second reflecting section" of the present disclosure.

As shown in FIG. 2 , the antenna section 120 is arranged in the + side end region in the X direction of the circuit board 110 and has a plurality of antenna elements 121 . A plurality of antenna elements 121 are arranged side by side in the Y direction. In the example shown in FIG. 2, a total of eight antenna elements 121 are provided. The Y direction corresponds to the "first direction" of this disclosure.

The four antenna elements 121 arranged in the area on the + side of the circuit board 110 in the X direction are antenna elements for transmission. transmit electromagnetic waves parallel to

The four antenna elements 121 arranged in the region on the − side of the circuit board 110 in the X direction are antenna elements for reception, and receive reflected waves from the + side of the circuit board 110 in the X direction.

By being arranged in this way, the antenna section 120 has directivity characteristics for transmission and reception on the + side of the X direction (first tilt direction) of the circuit board 110 .

As the antenna unit 120, typically, an end-fire array antenna having directivity on the + side of the X direction of the circuit board 110 is applied. An endfire array antenna includes a plurality of strip conductors arranged so that their longitudinal directions are parallel, and transmits and receives electromagnetic waves along the direction in which the plurality of strip conductors are arranged.

The electromagnetic wave transmitted by the transmission antenna element 121 is converted into a plane wave by the lens 130 and sent out toward the + side (here, substantially horizontal direction) in the X direction outside the radar device 100 . In addition, the reflected wave that the electromagnetic wave transmitted by the transmitting antenna element 121 is reflected by the target outside the device and returns is collected by the lens 130 and sent to the receiving antenna element 121 . Each antenna element 121 is connected to the signal processing IC via wiring formed on the circuit board 110 .

As shown in FIGS. 3A and 3B, antenna element 121 has first element 121A and second element 121B. The first element 121A and the second element 121B have an L-shape composed of a strip conductor 122 and an extension element 123. As shown in FIG.

The strip conductors 122 in the first element 121A are arranged along a first tilt direction parallel to the circuit board 110 and tilted with respect to the X direction and the Y direction. The X direction corresponds to the "second direction" of the present disclosure. The first tilt direction corresponds to the "third direction" of the present disclosure. The strip conductor 122 corresponds to the "first part" of this disclosure.

In addition, the two surface layer members 111 sandwiching the strip conductor 122 described above are arranged at equal intervals with respect to the strip conductor 122 .

The strip conductor 122 in the second element 121B extends from the Y-direction end of the inner layer member 112 in the first inclination direction. The strip conductor 122 of the second element 121B is arranged at a position overlapping the strip conductor 122 of the first element 121A when viewed from the Z direction.

The extension element 123 is arranged from the + side end of the strip conductor 122 in the X direction along a second tilt direction parallel to the circuit board 110 and orthogonal to the first tilt direction. The extension element 123 in the first element 121A extends to the + side in the second tilt direction. The extension element 123 in the second element 121B extends to the - side in the second tilt direction. The second tilt direction corresponds to the "fourth direction" of the present disclosure. Extension element 123 corresponds to the "second portion" of the present disclosure.

That is, the plurality of antenna elements 121 are arranged so as to radiate electromagnetic waves in the first tilt direction (see arrow F in FIG. 3A).

By arranging in this way, the antenna section 120 can increase the directivity toward the + side in the Y direction (lateral directivity) compared to a configuration in which the strip conductor is arranged along the X direction. becomes possible.

For example, as shown in FIG. 4, when the strip conductors are arranged along the X direction, the gain of the antenna section becomes a trapezoidal shape symmetrical with respect to the detection angle of 90° (see the dashed line).

On the other hand, in the case of the antenna unit 120 according to the present embodiment, the directivity of the electromagnetic wave is shifted to the + side (for example, the side larger than 90°) in the Y direction, so the directivity is shifted to the side larger than 90°. It becomes a one-sided gain. That is, the antenna section 120 according to the present embodiment can improve the directivity in the lateral direction (+ side in the Y direction).

Further, as shown in FIGS. 3A and 3B, the above-described surface layer member 111 is arranged on the circuit board 110 together with the first element 121A. The first ends 111A are arranged to face each other. That is, the first end portion 111A of the surface layer member 111 is arranged on the side opposite to the first inclination direction with respect to the extension element 123 of the first element 121A.

As described above, since the surface layer member 111 is electrically connected to the inner layer member 112 by the vias 114, the first end portion 111A functions as a reflecting surface that reflects electromagnetic waves emitted from the extension element 123. .

Therefore, when electromagnetic waves are radiated from the antenna section 120 in the negative direction in the X direction, the electromagnetic waves can be reflected in the first tilt direction by the first end portion 111A of the surface layer member 111 . Further, for example, if the surface layer member is not parallel to the extension element of the first element, the extension element and the surface layer member may interfere depending on the inclination angle of the strip conductor with respect to the Y direction.

In contrast, in the present embodiment, surface layer member 111 is parallel to extension element 123 of first element 121A, so interference between extension element 123 and surface layer member 111 can be suppressed.

In addition, as shown in FIG. 5, the ends of the extension elements 123 of the plurality of first elements 121A on the + side in the Y direction are arranged at the same position in the X direction. In other words, the ends of the extension elements 123 of the plurality of first elements 121A on the + side in the Y direction are arranged on the straight line L1 parallel to the Y direction at the first predetermined position in the X direction. Thereby, the performance of each element can be made uniform.

In addition, the negative ends in the Y direction of the extended elements 123 of the plurality of second elements 121B are arranged at the same position in the X direction. In other words, each negative Y-side end of the extended element 123 of the plurality of second elements 121B is arranged on the straight line L2 parallel to the Y direction at the second predetermined position in the X direction.

A lens 130 is arranged on the + side of the antenna section 120 in the X direction. The lens 130 narrows the beam of the electromagnetic wave transmitted by the transmission antenna element 121 and transmits the beam to the + side area in the Y direction outside the device. Then, the lens 130 collects the reflected waves that are returned after the transmitted electromagnetic waves are reflected by the target, and sends them to the antenna element 121 for reception. More preferably, the lens 130 is configured to narrow the beam of the electromagnetic wave to the extent that the electromagnetic wave transmitted by the transmitting antenna element 121 is converted into a plane wave.

The lens 130 improves the gain when the antenna section 120 transmits and receives electromagnetic waves, and the lens 130 also functions as a radome that protects the antenna section 120 .

As the lens 130, typically, a one-side convex lens having a convex surface on the + side in the X direction can be applied. However, as the lens 130, a double-sided convex lens, a ball lens, a Fresnel lens, or a combination thereof, or a combination thereof with a concave lens, or the like may be applied. Alternatively, the lens 130 may be convex on the negative side in the X direction.

Any material can be used to form the lens 130 as long as it functions as a lens. Tick polystyrene resin, ABS resin, or the like is used.

Effects of the radar device 100 according to the present embodiment configured as described above will be described.

For example, as shown in FIG. 6, assume that a vehicle C equipped with a radar device 100 attempts to change lanes to the right lane, which is adjacent to the current lane on the right. In this case, the radar device 100 mounted on the right rear of the vehicle C is used as a device for detecting the approach of the rear vehicle when changing lanes. The radar device 100 in this case is arranged so that the diagonally right rearward direction (B1 direction) of the vehicle C is on the + side of the X direction. The detection range R1 of the radar device 100 is within the right rear range of the vehicle C, for example. When another vehicle D1 traveling in the right lane enters the detection range R1, the other vehicle D1 is detected by the radar device 100. FIG.

In this embodiment, for example, the antenna element 121 is arranged in the B1 direction and the rearward direction so that the gain in the direction (the direction between the B1 direction and the rearward direction) that is inclined with respect to the B1 direction of the vehicle C increases. placed at an angle. As a result, the detection range R1 of the radar device 100 on the right rear side can be tilted obliquely to the left rear side (solid line reference). As a result, the detection range behind the vehicle C in the right lane is widened, making it easier to detect the other vehicle D1 traveling in the right lane.

Further, for example, as shown in FIG. 7, suppose that the vehicle C equipped with the radar device 100 tries to move backward from the parking space in order to leave the parking lot or the like. In this case, the radar devices 100 mounted on both ends of the rear side of the vehicle C are used as devices for rear detection when the vehicle is left behind. In this case, the radar device 100 is arranged so that the left oblique rear direction (B2 direction) of the vehicle C is on the + side of the X direction, and the right oblique rear direction (B3 direction) of the vehicle C is arranged on the X direction. Those arranged so as to be on the + side are provided respectively. The detection ranges R3 and R4 of the radar device 100 are, for example, the ranges on both the left and right sides of the rear side of the vehicle C. As shown in FIG. When moving objects E (pedestrians, other vehicles, etc.) on the left and right sides behind the vehicle C enter the detection ranges R3 and R4, the moving objects E are detected by the radar device 100. FIG.

In the present embodiment, for example, the gain in the direction in which the vehicle C is inclined with respect to the B2 direction (direction between the B2 direction and the left direction) and the direction in which the vehicle C is inclined with respect to the B3 direction (between the B3 direction and the right direction) Each antenna element 121 is arranged at an angle so that the gain in the direction of ) and . As a result, the detection ranges R3 and R4 of the radar device 100 are obliquely forward on both the left and right sides in the rear side, compared with the detection ranges R5 and R6 (see broken lines) in the configuration in which the antenna element 121 is arranged without being inclined. It can be tilted (see solid line). As a result, the detection range on the rear sides of the vehicle C is widened, and moving objects E on both the left and right sides of the rear sides of the vehicle C can be easily detected.

Further, for example, as shown in FIG. 8, assume that a vehicle C equipped with a radar device 100 attempts to turn right at an intersection. In this case, when the vehicle C is waiting for a right turn, the radar device 100 mounted on the front left end of the vehicle C detects a moving object (for example, an Another vehicle D2) is detected. The radar device 100 in this case is arranged so that the left side of the vehicle C (B4 direction in FIG. 8) is on the + side in the X direction. The detection range R7 of the radar device 100 is, for example, the front left range of the vehicle C. As shown in FIG.

In the present embodiment, antenna element 121 is arranged to be inclined so that the gain on the left oblique rear side of vehicle C (the direction between the B4 direction and the left direction) is improved. As a result, the detection range R7 of the radar device 100 on the left rear side of the vehicle C can be tilted (see the solid line) compared to the detection range R8 (see the broken line) in which the antenna element 121 is arranged without being tilted. . As a result, when the vehicle C is waiting for a right turn, the detection range in the diagonally left rear of the vehicle C is widened, and a moving object or the like in the diagonally left rear of the vehicle C can be easily detected.

As described above, in the present embodiment, by arranging antenna element 121 so as to radiate electromagnetic waves in the first tilt direction that is tilted with respect to the Y direction, side directivity of radar device 100 can be improved. can be done. As a result, it is possible to widen the detection range of the radar device 100 and improve the detection rate of side objects.

Further, since the antenna section 120 in this embodiment is configured by an end-fire array antenna, it can be configured simply by arranging the antenna element 121 on a normal circuit board 110 that is not specially processed.

For example, when a patch antenna is arranged on a circuit board as in the configuration described in Patent Document 1, there arises a problem that it is difficult to manufacture the device, such as the need to polish the circuit board.

However, in the present embodiment, the circuit board 110 can have a simple structure because it can be configured by simply arranging the antenna element 121 on the normal circuit board 110 . As a result, the radar device 100 can be manufactured easily.

That is, in the present embodiment, manufacturing is easy, and side directivity can be enhanced. Moreover, since it is not necessary to form a complicated structure such as polishing the circuit board 110, the manufacturing cost can be suppressed.

In addition, in the configuration described in Patent Document 1, by polishing the circuit board, the shape of the circuit board becomes a special shape such as a trapezoid. need arises.

On the other hand, in the present embodiment, since the antenna section 120 is composed of an end-fire array antenna, a lens having a simple shape such as a one-sided convex lens can be adopted as the lens 130 . As a result, the radar device 100 can have a simple shape as a whole, and the radar device 100 can be manufactured more easily.

Although the shape of the reflecting member 113 on the circuit board 110 was not mentioned in the above embodiment, the reflecting member 113 may be provided with a notch as shown in FIG.

Specifically, the X-direction end of the reflecting member 113 has a notch portion 113A that is recessed toward the antenna element 121 side. One notch portion 113</b>A is provided corresponding to each antenna element 121 . A portion corresponding to one antenna element 121 at the end of the reflecting member 113 in the X direction is composed of a first side A1, a second side A2, and a third side A3.

The first side A1 is a side parallel to the Y direction and provided at a position corresponding to the extension element 123 of the second element 121B. The second side A2 is a side extending in a direction parallel to the extension element 123 of the first element 121A (− side in the X direction) from the + side end of the first side A1 in the Y direction. The third side A3 extends from the end of the second side A2 on the + side in the Y direction in a direction orthogonal to the second side A2 (the side away from the antenna element 121), and is adjacent to the + side in the Y direction. is a side connected to the first side A1 in .

113 A of notch parts are parts comprised by 2nd edge|side A2 and 3rd edge|side A3. With this configuration, for example, the reflection area of the electromagnetic wave emitted from the extension element 123 of the first element 121A can be made a relatively narrow area.

If the reflection area is widened, the reflection member 113 may excessively reflect electromagnetic waves. Therefore, by making the reflection area relatively narrow, it is possible to suppress excessive reflection of the reflected wave.

Further, in the above embodiment, all the antenna elements 121 are configured to radiate electromagnetic waves in the same direction, but the present disclosure is not limited to this. The antenna element 121 may radiate electromagnetic waves in the first tilt direction. In FIG. 10, the antenna element 121 on the + side in the Y direction is arranged so as to radiate electromagnetic waves obliquely upward to the right in FIG. Also, the remaining antenna elements 121 are arranged to radiate electromagnetic waves in the X direction.

Also, as shown in FIG. 11, a plurality of antenna elements 121 may be arranged so as to radiate electromagnetic waves in different tilt directions. In FIG. 11, the antenna element 121 on the positive side in the Y direction and the antenna element 121 in the middle in the Y direction are arranged so as to radiate electromagnetic waves obliquely upward to the right in FIG. Also, the negative antenna element 121 in the Y direction is arranged so as to radiate electromagnetic waves obliquely upward to the left in FIG.

Further, as shown in FIG. 12, two antenna elements 121 among the plurality of antenna elements 121 may be arranged so as to radiate electromagnetic waves to the sides facing each other. In FIG. 12, the antenna element 121 on the + side in the Y direction is arranged so as to radiate electromagnetic waves diagonally upward to the left in FIG. Further, the negative antenna element 121 in the Y direction and the middle antenna element 121 in the Y direction are arranged so as to radiate electromagnetic waves obliquely upward to the right.

In addition, in the above-described embodiment, the receiving antenna element 121 is arranged at an angle in the same manner as the transmitting antenna element 121, but the present disclosure is not limited to this, and the antenna element 121 does not have to be arranged at an angle.

Further, in the above embodiment, the first end portion 111A of the surface member 111 is arranged parallel to the extension element 123, but the present disclosure is not limited to this, and they do not have to be arranged parallel.

Further, although the reflecting member 113 is provided in the above embodiment, the present disclosure is not limited to this, and the reflecting member may not be provided.

In addition, each of the above-described embodiments merely shows an example of implementation for carrying out the present disclosure, and the technical scope of the present disclosure should not be construed to be limited by these. That is, the present disclosure can be embodied in various forms without departing from its spirit or key features.

INDUSTRIAL APPLICABILITY The radar device of the present disclosure is useful as a radar device that is easy to manufacture and that can improve side directivity.

REFERENCE SIGNS LIST 100 radar device 110 circuit board 111 surface layer member 111A first end portion 111B second end portion 112 inner layer member 113 reflection member 114 via 120 antenna portion 121 antenna element 121A first element 121B second element 122 strip conductor 123 extension element 130 lens

Claims (4)

an antenna unit having a plurality of antenna elements configured by an endfire array antenna;
a circuit board on which the plurality of antenna elements are arranged side by side in a first direction;
with
At least some of the plurality of antenna elements are arranged in a second direction parallel to the substrate surface of the circuit board and orthogonal to the first direction, and in a direction inclined with respect to the first direction. arranged to radiate electromagnetic waves in a certain third direction ,
at least some of the plurality of antenna elements are arranged along the third direction; a second portion arranged along a fourth direction that is inclined with respect to the first direction;
A first reflector arranged opposite to the third direction with respect to the second portion of the antenna element and reflecting electromagnetic waves in the third direction,
The reflecting surface of the first reflecting portion has a stepped shape parallel to the second portion,
radar equipment. Each end of the second portion of the plurality of antenna elements is arranged on a straight line parallel to the first direction at a predetermined position in the second direction,
The radar device according to claim 1 . A second reflecting portion disposed inside the circuit board and reflecting electromagnetic waves radiated to the inside of the circuit board,
The second reflector is arranged in a range extending beyond the antenna element in the second direction,
The radar device according to claim 1 or 2 . an antenna unit having a plurality of antenna elements configured by an endfire array antenna;
a circuit board on which the plurality of antenna elements are arranged side by side in a first direction;
with
At least some of the plurality of antenna elements are arranged in a second direction parallel to the substrate surface of the circuit board and orthogonal to the first direction, and in a direction inclined with respect to the first direction. arranged to radiate electromagnetic waves in a certain third direction,
a second reflecting portion arranged inside the circuit board for reflecting electromagnetic waves radiated to the inside of the circuit board;
The second reflector is arranged in a range extending from the antenna element in the second direction,
The end portion of the second reflecting portion in the second direction includes a portion notched so as to be recessed toward the antenna element side,
radar equipment.

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