阅读说明：本技术 雷达装置以及雷达装置用托架 (Radar device and bracket for radar device ) 是由 樱井一正 境俊哉 于 2020-04-08 设计创作，主要内容包括：本发明涉及雷达装置以及雷达装置用托架。是通过辐射电波来探测存在于规定的探测范围内的物体的雷达装置(1、101),具备天线部(2)和电波反射部(4、400)。天线部构成为辐射电波。电波反射部配置于天线部的周围的区域且探测范围外的区域,并具有相对于雷达装置的设置面(44)的高度逐渐变化的反射面。(The present invention relates to a radar device and a bracket for the radar device. Disclosed is a radar device (1, 101) that detects an object existing within a predetermined detection range by radiating a radio wave, and is provided with an antenna unit (2) and a radio wave reflection unit (4, 400). The antenna unit is configured to radiate radio waves. The radio wave reflection unit is disposed in a region around the antenna unit and outside the detection range, and has a reflection surface whose height gradually changes with respect to a mounting surface (44) of the radar device.)

1. A radar device (1, 101) for detecting an object existing in a predetermined detection range by radiating a radio wave, comprising:

an antenna unit (2) configured to radiate the radio wave; and

the radio wave reflection unit is a radio wave reflection unit (4, 400) disposed in an area around the antenna unit and outside the detection range, and has a reflection surface whose height gradually changes with respect to a mounting surface (44) of the radar device.

2. The radar apparatus of claim 1,

the reflecting surface includes a plurality of metal surfaces (41, 42, 43) having different heights with respect to the installation surface.

3. The radar apparatus according to claim 2,

the plurality of metal surfaces are arranged in an azimuth detection direction with respect to an azimuth in which the object exists, among detection directions included in the detection range.

4. The radar apparatus according to claim 3,

the radio wave radiated to the outside of the detection range from the radio wave radiated from the antenna unit is set as a useless wave,

the lengths (L1, L2, L3) from one end to the other end in the azimuth detecting direction are shorter than the length of one wavelength of the unnecessary wave for each of the plurality of metal surfaces.

5. The radar apparatus according to any one of claims 2 to 4,

m is a positive integer, and the difference in height (H1, H2) between the plurality of metal surfaces with respect to the mounting surface is a value other than m times 1/2 the wavelength of the radio wave.

6. The radar apparatus according to any one of claims 3 to 5,

the plurality of metal surfaces are formed such that heights of the metal surfaces with respect to the installation surface gradually change along the azimuth detection direction.

7. The radar apparatus according to any one of claims 3 to 6,

at least one of the plurality of metal surfaces is configured to change in height with respect to the installation surface in a direction substantially parallel to the installation surface and substantially perpendicular to the azimuth detection direction.

8. The radar apparatus of claim 1,

the reflecting surface is formed in a curved surface shape.

9. The radar apparatus of claim 8,

the reflecting surfaces are arranged along an azimuth detection direction with respect to an azimuth in which the object exists, among detection directions included in the detection range.

10. The radar apparatus of claim 9,

the curved surface shape is configured to change in height with respect to the installation surface along a direction substantially parallel to the installation surface and substantially perpendicular to the azimuth detection direction.

11. The radar apparatus according to any one of claims 1 to 10,

at least a part of the radio wave reflection unit is present in a range in which a range surrounded by a line passing through an upper end (25) of a side wall (24) in the azimuth detection direction and substantially perpendicular to the installation surface and a line passing through the upper end and along a direction toward the installation surface, and an angle formed by the two lines is within 60 DEG, overlaps with a range within three wavelengths of the radio wave from the upper end along an azimuth detection direction with respect to an azimuth in which the object is present among detection directions included in the detection range, wherein the side wall (24) is a side wall of the antenna unit.

12. A bracket (5) for mounting the radar device according to any one of claims 1 to 11 to a vehicle,

the radar device includes a radio wave reflecting unit which is disposed in a region around an antenna unit that radiates a radio wave in a mounted state and which is out of a detection range, and which has a reflecting surface whose height with respect to a mounting surface of the radar device gradually changes.

Technical Field

The present disclosure relates to a radar device and a radar device bracket used for the radar device.

Background

Millimeter wave radars used for the purpose of automatic driving of a vehicle, collision prevention, and the like are known. The millimeter wave radar is a radar that irradiates a radio wave, detects a reflected wave of the irradiated radio wave reflected by an object, and detects the presence of the object in a predetermined detection area and a distance to the object. In such a millimeter wave radar, there are radio waves, i.e., useless waves, which deviate from a desired irradiation range or go around to an undesired region. Such unwanted waves bring about detection errors of the object.

Patent document 1 discloses a technique for reducing an azimuth detection error. The azimuth detection error is an error regarding the azimuth of an object with reference to the radar device. Patent document 1 discloses a technique of reducing errors by providing an absorption element made of a material that absorbs electromagnetic waves in a case of a radar device, thereby suppressing multiple reflections of unwanted waves and the like.

Patent document 1: japanese patent laid-open publication No. 2014-547812

However, as a result of detailed studies by the inventors, the technique described in patent document 1 has found a problem that the manufacturing cost increases because an absorption element needs to be provided separately from the radar device.

Disclosure of Invention

In an aspect of the present disclosure, it is preferable to provide a radar apparatus of a new configuration capable of reducing an azimuth detection error of a radar and reducing a manufacturing cost.

One aspect of the present disclosure is a radar device that detects an object existing within a predetermined detection range by radiating a radio wave, and includes an antenna unit and a radio wave reflection unit. The antenna section radiates an electric wave. The radio wave reflecting unit is disposed in a region around the antenna unit and outside the detection range, and has a reflecting surface whose height gradually changes with respect to the installation surface of the radar device.

According to such a configuration, in the radio wave reflecting unit provided around the radar, the unnecessary wave is reflected by the reflecting surface whose height gradually changes with respect to the installation surface, and the phases of the respective reflected waves from the reflecting surface are dispersed, thereby reducing phase disturbance caused by interference of the reflected unnecessary wave with the radar radiation wave. Therefore, the azimuth detection error of the radar can be reduced. Further, it is possible to reduce the object detection error of the radar without providing an absorption element of the radio wave or the like, and it is possible to reduce the manufacturing cost in the point that the absorption element of the radio wave or the like may not be provided.

One aspect of the present disclosure is a bracket for mounting a radar device on a vehicle, and includes a radio wave reflection unit. The radio wave reflection unit is disposed in a region outside a detection range and around an antenna unit that radiates radio waves in a mounted state, and has a reflection surface whose height with respect to a mounting surface of the radar device gradually changes.

With this configuration, the bracket alone can provide the same effects as those described above.

Drawings

Fig. 1a is a schematic diagram showing a radar device according to a first embodiment. B of fig. 1 is a schematic cross-sectional view at line IB-IB of a of fig. 1. C of fig. 1 is a schematic cross-sectional view at the IC-IC line of a of fig. 1.

Fig. 2a is a schematic diagram showing a radar device according to modification 1 of the first embodiment. B of FIG. 2 is a schematic sectional view taken along line IIB-IIB of A of FIG. 2. C of fig. 2 is a schematic cross-sectional view at line IIC-IIC of a of fig. 2.

Fig. 3a is a schematic diagram showing a radar device according to modification 2 of the first embodiment. B of fig. 3 is a schematic cross-sectional view at line IIIB-IIIB of a of fig. 3. Fig. 3C is a schematic cross-sectional view at line IIIC-IIIC of a of fig. 3.

Fig. 4a is a schematic diagram showing a radar device according to modification 3 of the first embodiment. B of fig. 4 is a schematic cross-sectional view at the line IVB-IVB of a of fig. 4. C of fig. 4 is a schematic cross-sectional view at the line IVC-IVC of a of fig. 4.

Fig. 5a is a schematic diagram showing a radar device according to modification 4 of the first embodiment. B of fig. 5 is a schematic cross-sectional view taken along line VB-VB of a of fig. 5. C of fig. 5 is a schematic cross-sectional view at line VC-VC of a of fig. 5.

Fig. 6a is a schematic diagram showing a radar device according to modification 5 of the first embodiment. B of fig. 6 is a schematic cross-sectional view at line VIB-VIB of a of fig. 6. C of fig. 6 is a schematic cross-sectional view at the VIC-VIC line of a of fig. 6.

Fig. 7a is a schematic diagram showing a radar device according to modification 6 of the first embodiment. B of fig. 7 is a schematic cross-sectional view at VIIB-VIIB line of a of fig. 7. Fig. 7C is a schematic cross-sectional view at VIIC-VIIC line of a of fig. 7.

Fig. 8a is a schematic diagram showing a radar device according to modification 7 of the first embodiment. B of fig. 8 is a schematic cross-sectional view at VIIIB-VIIIB line of a of fig. 8. C of fig. 8 is a schematic cross-sectional view at VIIIC-VIIIC line of a of fig. 8.

Fig. 9a is a schematic diagram showing a radar device according to modification 8 of the first embodiment. B of fig. 9 is a schematic cross-sectional view at line IXB-IXB of a of fig. 9. C of FIG. 9 is a schematic cross-sectional view at the IXC-IXC line of A of FIG. 9.

Fig. 10a is a schematic diagram showing a radar device according to modification 9 of the first embodiment. B of fig. 10 is a schematic cross-sectional view at line XB-XB of fig. 10 a. C of FIG. 10 is a schematic cross-sectional view at XC-XC line of A of FIG. 10.

Fig. 11a is a schematic diagram showing a radar device according to modification 10 of the first embodiment. Fig. 11B is a schematic cross-sectional view at line XIB-XIB of fig. 11 a. Fig. 11C is a schematic cross-sectional view at XIC-XIC line of fig. 11 a.

Fig. 12 is a diagram showing an effect of improving the azimuth detection error of the radar device according to the first embodiment.

Fig. 13 is a diagram showing changes in antenna directivity of the radar device according to the first embodiment.

Fig. 14a is a schematic diagram showing a radar device according to a second embodiment. B of fig. 14 is a schematic cross-sectional view taken along line XIVB-XIVB of a of fig. 14. Fig. 14C is a schematic cross-sectional view at XIVC-XIVC line of a of fig. 14.

Fig. 15a is a schematic diagram showing a radar device according to modification 1 of the second embodiment. B of fig. 15 is a schematic cross-sectional view taken along line XVB-XVB of a of fig. 15. Fig. 15C is a schematic cross-sectional view at the line XVC-XVC of fig. 15 a.

Fig. 16a is a schematic diagram showing a radar device according to modification 2 of the second embodiment. Fig. 16B is a schematic cross-sectional view taken along line XVIB-XVIB of a of fig. 16. Fig. 16C is a schematic cross-sectional view taken along line XVIC-XVIC of a in fig. 16.

Fig. 17a is a schematic diagram showing a radar device according to modification 3 of the second embodiment. Fig. 17B is a schematic cross-sectional view at line XVIIB-XVIIB of fig. 17 a. Fig. 17C is a schematic cross-sectional view at line xviiic-xviiic of a of fig. 17.

Fig. 18a is a schematic diagram showing a radar device according to modification 4 of the second embodiment. Fig. 18B is a schematic sectional view taken on line XVIIIB-XVIIIB of a in fig. 18. Fig. 18C is a schematic cross-sectional view at line XVIIIC-XVIIIC of a of fig. 18.

Fig. 19a is a schematic diagram showing a radar device according to modification 5 of the second embodiment. B of fig. 19 is a schematic cross-sectional view at line XIXB-XIXB of a of fig. 19. C of fig. 19 is a schematic cross-sectional view at the line XIXC-XIXC of a of fig. 19.

Fig. 20 is a diagram showing an effect of improving the azimuth detection error of the radar device according to the second embodiment.

Fig. 21 is a diagram showing changes in antenna directivity of the radar device according to the second embodiment.

Detailed Description

Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings.

[1. first embodiment ]

[ 1-1. Structure ]

The radar device 1 according to the first embodiment is mounted on a vehicle 10, radiates a radiation wave, which is a radio wave having a predetermined frequency, and detects a reflected wave of the radiation wave reflected by an object to detect the object. The radar device 1 is installed, for example, inside a bumper of the vehicle 10, and detects an object around the vehicle 10.

The radar device 1 shown in fig. 1 includes an antenna unit 2 and a radio wave reflection unit 4. The antenna section 2 includes a housing 3. The radar device 1 may include a cover for protecting the antenna unit 2.

The radar device 1 includes a transmission/reception circuit that transmits/receives a radiation wave and a reflected wave via the antenna unit 2, a signal processing unit that processes a reception signal received by the transmission/reception circuit in order to acquire information of a surrounding object, and the like.

The antenna unit 2 includes a rectangular antenna substrate 21. A plurality of antenna elements 22 for transmitting and receiving radio waves are provided on one of the two surfaces of the antenna substrate 21. Hereinafter, the surface of the antenna substrate 21 on which the antenna element 22 is formed is referred to as an antenna surface 23. The antenna substrate 21 is housed in the case 3 and fixed to the case 3. The case 3 is made of a metal material and functions as a ground.

The antenna unit 2 may not necessarily include the housing 3, and may be directly provided in the vehicle 10.

Here, the longitudinal direction of the antenna substrate 21 is defined as the x-axis direction, the short-side direction is defined as the y-axis direction, and the axial direction perpendicular to the antenna surface 23 of the antenna substrate 21 is defined as the z-axis direction. Hereinafter, description will be given by appropriately using the xyz three-dimensional coordinate axis. Hereinafter, the positive direction of the z-axis is referred to as "front", and the negative direction of the z-axis is referred to as "rear". The side on which the radiation wave is radiated is set to the antenna front side with the antenna surface 23 as a boundary, and the opposite side is set to the antenna rear side. The x-axis direction is a direction in which an orientation of an object (here, an orientation in the horizontal direction) exists, and is hereinafter also referred to as an orientation detection direction.

The plurality of antenna elements 22 are arranged in the antenna substrate 21 along the x-axis direction and the y-axis direction in fig. 1. Further, the antenna elements 22 arranged in a row along the y-axis direction among the plurality of antenna elements 22 constitute an array antenna. That is, the antenna unit 2 has a structure in which a plurality of array antennas are arranged along the x-axis direction.

When the radar device 1 is mounted on the vehicle 10, the radar device is mounted so that the y-axis direction coincides with the vehicle height direction, the x-axis direction coincides with the horizontal direction, and the z-axis direction coincides with the center direction of the detection area. The detection area is an area within a range forming a predetermined solid angle from the center of the antenna surface 23. Among the radiation waves, the radiation wave radiated to the outside of the detection region is also referred to as an unnecessary wave hereinafter.

Any one of the array antennas is used as a transmission antenna, and the other array antennas are used as reception antennas. However, the form of the transmission antenna and the reception antenna is not limited to this, and the arrangement of the array antenna used as the transmission antenna and the array antenna used as the reception antenna can be arbitrarily set. In addition, all the array antennas may be used as the transmission antenna and the reception antenna.

The radio wave reflecting unit 4 is made of a metal material. The radio wave reflection unit 4 is designed in such a shape that the unnecessary waves radiated from the antenna unit 2 and leaking to the outside of the detection area are reflected by the radio wave reflection unit 4.

The radio wave reflection units 4 are arranged one by one in the azimuth detection direction, i.e., in the x-axis direction in the figure, so as to face each other with the antenna unit 2 interposed therebetween. The two radio wave reflection units 4 are directly provided on the installation surface 44 of the vehicle 10. The two radio wave reflecting portions 4 have symmetrical shapes in the azimuth detecting direction. Hereinafter, the configuration and shape of the radio wave reflecting unit 4 will be specifically described with attention paid to one radio wave reflecting unit 4.

The length of the radio wave reflecting section 4 in the y-axis direction is formed longer than the width of the housing 3 in the y-axis direction.

The radio wave reflection unit 4 further includes: a first metal surface 41, a second metal surface 42 and a third metal surface 43. These first metal surface 41, second metal surface 42, and third metal surface 43 function as reflection surfaces that reflect unnecessary waves. The first metal surface 41, the second metal surface 42, and the third metal surface 43 are different in height from each other in the z-axis direction, and are formed in a three-step shape. Specifically, the metal material extends forward from the installation surface 44, horizontally bends by 90 ° so as to be separated from the antenna unit 2, and extends to form the first metal surface 41. The metal material is bent backward by 90 ° from the first metal surface 41 and extended, and further horizontally bent by 90 ° away from the antenna unit 2 and extended to form a second metal surface 42. The metal material is bent backward by 90 ° from the second metal surface 42 again, and further horizontally bent by 90 ° so as to be separated from the antenna unit 2, and then extended to form a third metal surface 43. However, the first metal surface 41, the second metal surface 42, and the third metal surface 43 may be integrally formed, instead of sequentially forming these metal surfaces, for example, by initially forming the first metal surface 41.

In this way, in the first embodiment, the height (i.e., the height from the installation surface 44) of the third metal surface 43, which is the outermost metal surface among the first metal surface 41, the second metal surface 42, and the third metal surface 43, is formed to be gradually lower from the center of the antenna unit 2 toward the outer edge of the third metal surface 43. The first metal surface 41, the second metal surface 42, and the third metal surface 43 are formed substantially parallel to the antenna surface 23.

Here, a range enclosed by the line a1 and the line a2, where the angle formed by the two lines (a1 and a2) is approximately 60 ° or less, is defined as a range a, where the line a1 is a line passing through the upper end 25 of the side wall 24 in the azimuth detection direction and substantially perpendicular to the installation surface 44, the side wall 24 is a side wall of the antenna unit 2, and the line a2 is a line passing through the upper end 25 and extending in a direction toward the installation surface 44. The range within three wavelengths λ of the radio wave from the upper end 25 along the azimuth detection direction is defined as range B. The radio wave reflecting unit 4 is disposed entirely within a range S where the range a and the range B overlap. Note that the range S is also the same in other embodiments described later, and therefore, in other embodiments, the description and illustration are omitted.

The width of each metal surface of the radio wave reflecting unit 4, i.e., the length from one end to the other end in the x-axis direction in the drawing, is shorter than one wavelength of the radio wave. In the first embodiment, the length L1 of the first metal surface 41, the length L2 of the second metal surface 42, and the length L3 of the third metal surface 43 are all equal. The length L1 of the first metal surface 41, the length L2 of the second metal surface 42, and the length L3 of the third metal surface 43 may be different from each other.

Where m is a positive integer, the difference H1 and H2 in height of each metal surface of the radio wave reflection unit 4 with respect to the installation surface 44 in the z-axis direction in the figure are both set to values other than m times 1/2 the wavelength of the radio wave. Here, H1 is the difference between the height from the mounting surface 44 to the first metal surface 41 and the height from the mounting surface 44 to the second metal surface 42. H2 is the difference between the height from the mounting surface 44 to the second metal surface 42 and the height from the mounting surface 44 to the third metal surface 43. In the present first embodiment, H1 and H2 are equal to each other. Further, H1 and H2 may be different from each other as long as the above conditions are satisfied.

< modification 1 of the first embodiment >

Next, a modified example 1 of the first embodiment will be described with reference to fig. 2. The basic configuration of modification 1 is the same as that of the first embodiment, and the same reference numerals are given to the common configurations. Hereinafter, the following description will focus on the differences.

In modification 1, the radar device 1 includes a bracket 5 between the radar device 1 and a vehicle 10 on which the radar device 1 is installed. The bracket 5 is used to couple the radar apparatus 1 to the vehicle 10. The bracket 5 is made of metal.

The radar device 1 is mounted to a vehicle 10 via a bracket 5. Specifically, the bracket 5 may be attached to the vehicle 10, the radar device 1 may be attached to the bracket 5, and the radar device 1 may be fixed to the vehicle 10 with the bracket 5 interposed between the radar device and the vehicle 10.

The radio wave reflecting portion 4 is formed integrally with the bracket 5 and can be formed by bending by press working or the like.

The first metal surface 41, the second metal surface 42, and the third metal surface 43 have the same configuration as in the first embodiment.

< modification 2 of the first embodiment >

Next, a modified example 2 of the first embodiment will be described with reference to fig. 3. The basic configuration of modification 2 is the same as that of the first embodiment, and the same reference numerals are given to the common configurations. Hereinafter, the following description will focus on the differences.

The radio wave reflecting portion 4 in modification 2 is provided directly to the case 3, and is formed by bending a metal material upward from the contact point portion between the vehicle 10 and both side surfaces of the case 3 in the x-axis direction.

Further, the housing 3 and the radio wave reflecting portion 4 may be mounted as separate members, or may be integrally formed.

The first metal surface 41, the second metal surface 42, and the third metal surface 43 have the same configuration as in the first embodiment.

< modification 3 of the first embodiment >

Next, a modified example 3 of the first embodiment will be described with reference to fig. 4. Basic configurations of modifications 3 to 10 of the first embodiment to be described later are the same as those of modification 1 of the first embodiment, and the same reference numerals are given to common configurations. Hereinafter, the following description will focus on the differences.

In modification 3, the first metal surface 41, the second metal surface 42, and the third metal surface 43 of the radio wave reflecting unit 4 are formed in a three-step shape with different heights in the z-axis direction. Specifically, the metal material extends forward from the installation surface 44, horizontally bends by 90 ° so as to be separated from the antenna unit 2, and extends to form the first metal surface 41. The metal material is bent forward by 90 ° from the first metal surface 41 and extended, and further bent horizontally by 90 ° away from the antenna portion 2 and extended, thereby forming a second metal surface 42. The metal material is bent forward again by 90 ° from the second metal surface 42 and extended, and further bent horizontally by 90 ° away from the antenna unit 2 and extended, thereby forming a third metal surface 43. As described above, in modification 3, the height of the third metal surface 43, which is the outermost metal surface among the first metal surface 41, the second metal surface 42, and the third metal surface 43, is formed to be gradually higher from the center of the antenna portion 2 toward the outer edge of the third metal surface 43.

< modification example 4 of the first embodiment >

Next, a modified example 4 of the first embodiment will be described with reference to fig. 5.

The metal surfaces of the radio wave reflecting unit 4 in modification 4 are formed to have different heights in the z-axis direction, and are arranged in steps with irregular heights.

Specifically, the radio wave reflecting unit 4 has a convex portion extending forward, and a concave portion continuous with the convex portion and recessed rearward. The metal surface in the radio wave reflecting unit 4 of modification 4 is formed horizontally in the x-axis direction.

In the present modification, the width of each metal surface of the radio wave reflecting unit 4, that is, the length from one end to the other end in the x-axis direction in the drawing is configured to be shorter than one wavelength of the radio wave. Further, where m is a positive integer, the difference in height of each metal surface of the radio wave reflecting unit 4 with respect to the installation surface 44 in the z-axis direction in the figure is set to a value other than a value equal to m times 1/2 of the wavelength of the radio wave.

< modification example 5 of the first embodiment >

Next, a modified example 5 of the first embodiment and fig. 6 will be described with reference to fig. 6.

In modification 5, the first metal surface 41, the second metal surface 42, and the third metal surface 43 are connected by a slope. That is, the first metal surface 41, the second metal surface 42, and the third metal surface 43 are connected by a surface that is not parallel to the x-axis direction. Specifically, the metal material extending diagonally forward from the mounting surface 44 so as to be away from the antenna unit 2 is bent horizontally in the x-axis direction and extends to form the first metal surface 41. The metal material is bent and extended obliquely rearward from the first metal surface 41 so as to be away from the antenna unit 2, and further bent and extended horizontally in the x-axis direction, thereby forming a second metal surface 42. The metal material is bent and extended obliquely rearward from the second metal surface 42 so as to be away from the antenna unit 2, and further bent and extended horizontally in the x-axis direction, thereby forming a third metal surface 43.

< modification 6 of the first embodiment

Next, a modified example 6 of the first embodiment will be described with reference to fig. 7.

The first metal surface 41, the second metal surface 42, and the third metal surface 43 in modification 6 are configured to have an angle with respect to the x-axis direction and to be non-parallel. Specifically, the metal material extending forward from the installation surface 44 is bent and extended obliquely forward so as to be apart from the antenna unit 2, thereby forming the first metal surface 41. The metal material is bent and extended rearward from the first metal surface 41, and further bent and extended obliquely forward so as to be apart from the antenna portion 2, thereby forming a second metal surface 42. The metal material is bent and extended backward again from the second metal surface 42, and further bent and extended obliquely forward so as to be apart from the antenna portion 2, thereby forming a third metal surface 43.

< modification example 7 of the first embodiment >

Next, a modified example 7 of the first embodiment will be described with reference to fig. 8.

The first metal surface 41, the second metal surface 42, and the third metal surface 43 in modification 7 are configured such that the height from the installation surface 44 changes along a direction substantially parallel to the installation surface 44 and substantially perpendicular to the azimuth detection direction. Specifically, the first metal surface 41, the second metal surface 42, and the third metal surface 43 of the radio wave reflecting unit 4 are configured to have a stepped shape along the y-axis direction.

< modification example 8 of the first embodiment >

Next, a modified example 8 of the first embodiment will be described with reference to fig. 9.

The first metal surface 41, the second metal surface 42, and the third metal surface 43 in modification 8 are configured to change in height with respect to the installation surface 44 in a direction substantially parallel to the installation surface 44 and substantially perpendicular to the azimuth detection direction, as in modification 7 described above. Specifically, the first metal surface 41, the second metal surface 42, and the third metal surface 43 of the radio wave reflecting unit 4 are formed in a chevron shape along the y-axis direction.

< modification 9 of the first embodiment >

Next, a modified example 9 of the first embodiment will be described with reference to fig. 10.

The first metal surface 41, the second metal surface 42, and the third metal surface 43 in modification 9 are configured to change in height with respect to the installation surface 44 in a direction substantially parallel to the installation surface 44 and substantially perpendicular to the azimuth detection direction, similarly to modifications 7 and 8 described above. Specifically, the first metal surface 41, the second metal surface 42, and the third metal surface 43 of the radio wave reflecting unit 4 are configured to have a curved surface shape along the y-axis direction.

< modification example 10 of the first embodiment

Next, a modified example 10 of the first embodiment will be described with reference to fig. 11.

In the first embodiment, two radio wave reflecting units 4 are provided along the x-axis direction so as to face each other with the antenna unit 2 interposed therebetween, but in modification 10, four radio wave reflecting units 4 are provided. That is, the x-axis and y-axis directions in the drawing are both azimuth detection directions, and the x-axis and y-axis directions are respectively provided so as to face each other with the antenna unit 2 interposed therebetween, and are arranged so as to surround the outer periphery of the antenna unit 2. The two radio wave reflecting portions 4 in the y-axis direction have symmetrical shapes in the azimuth detecting direction.

The first metal surface 41, the second metal surface 42, and the third metal surface 43 of the radio wave reflecting unit 4 in the y-axis direction are formed substantially parallel to the y-axis in the figure. The shape, width, and height difference of the metal surfaces 41, 42, and 43 with respect to the installation surface 44 are the same as those of the metal surfaces 41, 42, and 43 of the radio wave reflecting unit 4 in the x-axis direction.

[ 1-2. Effect ]

In the radar device 1 configured as described above, most of the unnecessary waves, which are radio waves radiated from the antenna unit 2 and directed outside the detection region, are reflected by the first metal surface 41, the second metal surface 42, and the third metal surface 43 of the radio wave reflecting unit 4. Thereby, the phases of these unnecessary waves can be dispersed. In particular, the widths L1, L2, and L3 of the respective metal surfaces of the radio wave reflecting unit 4 are all shorter than one wavelength of the radio wave, and therefore reflected waves of the same phase are not generated. The differences H1 and H2 in height of the metal surfaces of the radio wave reflecting unit 4 with respect to the installation surface 44 are all values other than a value equal to one-half of the wavelength of the radio wave multiplied by m. Therefore, the difference in the path length of the radio wave due to the difference in the height of each metal surface 41, 42, 43 is not a positive integral multiple of one wavelength of the radio wave, and the phase deviation due to the reflection by each metal surface 41, 42, 43 occurs.

According to the first embodiment described in detail above, the following effects are obtained.

(1a) The first metal surface 41, the second metal surface 42, and the third metal surface 43 having different heights of the radio wave reflecting unit 4 reflect the unnecessary waves on the first metal surface 41, the second metal surface 42, and the third metal surface 43, respectively, thereby dispersing the phases of the reflected waves. Further, phase disturbance due to interference of the reflected unnecessary wave with the radar radiation wave can be reduced. Therefore, the azimuth detection error of the radar can be reduced.

Fig. 12 shows the results of measuring the detection azimuth accuracy in the radar device 1 provided with the radio wave reflection unit 4 and in the radar device without the radio wave reflection unit. As shown in the figure, in the radar device without the radio wave reflecting unit, the maximum error E1 of the azimuth accuracy is about 1.5 degrees, whereas in the radar device 1 provided with the radio wave reflecting unit 4, the maximum error E2 of the azimuth accuracy is about 1 degree. Therefore, the detection azimuth accuracy is improved.

Fig. 13 shows the results of calculating the directivity of the gain by simulation in the radar device 1 provided with the radio wave reflecting unit 4 and in the radar device without the radio wave reflecting unit. As shown in the figure, in the radar device provided with the radio wave reflection unit 4, the gain outside the detection region is significantly reduced as compared with the case where the radio wave reflection unit is omitted.

(1b) In addition, according to the radar device 1 of the present disclosure, it is possible to reduce an object detection error of the radar without providing an absorption element of radio waves or the like. Therefore, it is possible to eliminate the need for radio wave absorbing elements and the like, and accordingly, it is possible to avoid an increase in manufacturing cost and to reduce manufacturing cost.

[2. second embodiment ]

[ 2-1. Structure ]

Since the basic configuration of the second embodiment is the same as that of the first embodiment, a different point will be described below. Note that the same reference numerals as those in the first embodiment denote the same structures, and the above description is referred to.

As shown in fig. 14, in the radar device 101 according to the second embodiment, two radio wave reflection units 400 are provided directly on the vehicle 10. The radio wave reflection units 400 are arranged one by one so as to face each other with the antenna unit 2 interposed therebetween along the x-axis direction in the figure. The two radio wave reflecting portions 400 have a symmetrical shape in the azimuth detecting direction. Hereinafter, the configuration and shape of the radio wave reflecting unit 400 will be specifically described with attention paid to one radio wave reflecting unit 400.

The radio wave reflecting unit 400 has a curved surface portion 401. The curved surface portion 401 is curved so as to gradually change in height with respect to the installation surface 44 of the radar device 101. Specifically, the curved surface portion 401 is curved such that the height in the z-axis direction becomes higher as the distance from the antenna portion 2 increases. The curved surface portion 401 functions as a reflection surface.

< modification example 1 of the second embodiment >

Next, modified example 1 of the second embodiment will be described with reference to fig. 15. The basic configuration of modification 1 is the same as that of the second embodiment, and the same reference numerals are given to the common configurations. Hereinafter, the following description will focus on the differences.

In modification 1, the radar device 101 includes a bracket 5 between the radar device 101 and the vehicle 10 on which the radar device 101 is installed. The bracket 5 is used to couple the radar device 101 to the vehicle 10. The bracket 5 is made of metal.

The radar device 101 is mounted to the vehicle 10 via the bracket 5. Specifically, the bracket 5 may be attached to the vehicle 10, the radar device 101 may be attached to the bracket 5, and the radar device 101 may be fixed to the vehicle 10 with the bracket 5 interposed between the radar device and the vehicle 10.

The radio wave reflecting portion 400 is formed integrally with the bracket 5 and is formed by bending by press working or the like.

The structure of the curved surface portion 401 is the same as that of the second embodiment.

< modification 2 of the second embodiment >

Next, a modified example 2 of the second embodiment will be described with reference to fig. 16. The basic configuration of modification 2 is the same as that of the second embodiment, and the same reference numerals are given to the common configurations. Hereinafter, the following description will focus on the differences.

The radio wave reflecting portion 400 in modification 2 is provided directly to the case 3, and is formed by bending a metal material upward from a contact portion between both side surfaces of the case 3 in the x-axis direction and the vehicle 10.

Further, the housing 3 and the radio wave reflecting portion 400 may be mounted as separate components, or may be integrally formed.

The structure of the curved surface portion 401 is the same as that of the second embodiment.

< modification 3 of the second embodiment >

Next, a modified example 3 of the second embodiment will be described with reference to fig. 17. Basic configurations of modifications 3 to 5 of the second embodiment to be described later are the same as those of modification 1 of the second embodiment, and the same reference numerals are given to common configurations. Hereinafter, the following description will focus on the differences.

The curved surface portion 401 of the radio wave reflecting unit 400 in modification 4 is configured to gradually change in height with respect to the installation surface 44 in a direction substantially parallel to the installation surface 44 and substantially perpendicular to the azimuth detecting direction. Specifically, the curved surface portion 401 of the radio wave reflecting portion 400 is formed in a hemispherical shape along the y-axis direction.

< modification example 4 of the second embodiment >

Next, a modified example 3 of the second embodiment will be described with reference to fig. 18.

The curved surface portion 401 of the radio wave reflecting unit 400 in modification 4 is configured to gradually change in height with respect to the installation surface 44 in a direction substantially parallel to the installation surface 44 and substantially perpendicular to the azimuth detecting direction. Specifically, the curved surface portion 401 of the radio wave reflecting portion 400 is configured to have a shape in which portions of the outer surfaces of the three hemispheres are overlapped and connected to each other along the y-axis direction.

< modification example 5 of the second embodiment >

Next, a modified example 5 of the second embodiment will be described with reference to fig. 19.

In the second embodiment, two radio wave reflecting units 400 are provided so as to face each other with the antenna unit 2 interposed therebetween along the x-axis direction, but in modification 5, there are four radio wave reflecting units 400. That is, one antenna unit 2 is provided so as to face each other in the x-axis direction and the y-axis direction, and the antenna unit 2 is arranged so as to surround the outer periphery thereof. The two radio wave reflection units 400 in the y-axis direction have a symmetrical shape in the azimuth detection direction.

The shape and curvature (i.e., the case of bending) of each curved surface portion 401 in the y-axis direction are the same as those of the curved surface portion 401 in the x-axis direction.

[ 2-2. Effect and Effect ]

Most of the radio waves radiated from the antenna unit 2 and directed outside the detection region, i.e., the unwanted waves, are reflected by the curved surface portion 401 of the radio wave reflecting unit 400. Thereby, the phases of these unnecessary waves can be dispersed.

According to the second embodiment described in detail above, the following effects are obtained.

(2a) By reflecting the unnecessary waves by the curved surface portion 401 of the radio wave reflecting portion 400 and diffusing the respective reflected waves, it is possible to reduce phase disturbance caused by interference of the reflected unnecessary waves with the radar radiation wave. Therefore, the azimuth detection error of the radar can be reduced.

Fig. 20 shows the results of measuring the detection azimuth accuracy in the radar device 101 provided with the radio wave reflection unit 400 and in the radar device without the radio wave reflection unit. As shown in the figure, in the radar device without the radio wave reflecting unit, the maximum error E3 of the azimuth accuracy is about 1 degree, whereas in the radar device 101 provided with the radio wave reflecting unit 400, the maximum error E4 of the azimuth accuracy is about 0.5 degree. Therefore, the detection azimuth accuracy is improved.

Fig. 21 shows the result of calculating the directivity of the gain by simulation in the radar device 101 provided with the radio wave reflecting unit 400 and in the radar device without the radio wave reflecting unit. As shown in the drawing, in the radar device 101 provided with the radio wave reflection unit 400, the gain outside the detection region is significantly reduced as compared with the case where the radio wave reflection unit is omitted.

(2b) Further, as in the first embodiment described above, it is possible to reduce an object detection error of the radar without providing an absorption element of radio waves or the like. Therefore, the radio wave absorbing element and the like are not required, and accordingly, the increase in the manufacturing cost can be avoided.

[3 ] other embodiments ]

While the embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above, and various modifications can be made.

(3a) In the above embodiment, the number of metal surfaces in the radio wave reflecting portion is three, but the number of metal surfaces in the radio wave reflecting portion is not limited to three.

The location of the radio wave reflecting unit does not necessarily have to be the direction of direction detection, and the radio wave reflecting unit does not necessarily have to be disposed at an opposing position.

(3b) In the above embodiment, the configuration in which all the radio wave reflecting parts are arranged within the range S is exemplified, but the present invention is not limited thereto. For example, a part of the radio wave reflecting unit may be disposed within the range S.

(3c) In the present disclosure, the radar device having the radio wave reflecting unit is described, but the present disclosure may be applied to a bracket alone having the radio wave reflecting unit, for example. Thus, the same effects as those described above can be obtained by the bracket alone.

(3d) The plurality of functions of one component in the above embodiments may be realized by a plurality of components, or one function of one component may be realized by a plurality of components. Further, a plurality of functions provided by a plurality of components may be realized by one component, or one function realized by a plurality of components may be realized by one component. In addition, a part of the structure of the above embodiment may be omitted. In addition, at least a part of the structure of the above-described embodiment may be added to or replaced with the structure of the other above-described embodiment.