JP2020080527A - Antenna device - Google Patents

Abstract

To provide a technique for realizing a unidirectional antenna device with high gain.SOLUTION: An antenna device 100 includes a metal base plate 1, and a radiator 3 and a director 5 provided on the metal ground plane 1. The director 5 is provided on the metal base plate 1 as convex portions of N metal bodies 50 arranged from the radiator 3 along a predetermined arrangement direction. In the N convex portions forming the director 5, the length (width w) of the i+1-th (i=1 to (N-1)) convex portion in the width direction (direction orthogonal to the arrangement direction on the ground plane) is longer than the width of the i-th convex portion in the width direction in ascending order from a radiating element.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an antenna device.

  Transmitting and receiving radio waves in a specific direction, such as radar and sensor devices mounted on aircraft and vehicles, wireless LAN and MIMO (Multiple-Input and Multiple-Output) transmission in 5G mobile communication systems (5G) The role of a small, unidirectional antenna that can do this is important.

  A Yagi-Uda monopole array antenna, for example, is known as one of low-profile directional antennas in which radiating elements are linearly arranged on a metal ground plane (see, for example, Patent Document 1). FIG. 15 is a structural perspective view of the Yagi-Uda monopole array antenna 100h. One rod-shaped radiator 3h and one rod-shaped reflector 7h, and a plurality of (10 in the illustrated example) metal. A waveguide 5h composed of a body 50h and a waveguide 5h are arranged on the base plate 1h at a predetermined interval in a straight line direction. The operating principle of the Yagi-Uda monopole array antenna is well known, and the electromagnetic wave intensity in a specific direction is obtained by superimposing the electromagnetic wave emitted from the radiator 3h and the electromagnetic wave re-emitted from the reflector 7h and the director 5h. It is to enhance

  On the other hand, from a different point of view, the array of directors in the Yagi-Uda monopole array antenna can be regarded as a kind of so-called corrugated structure in which metal walls are arrayed periodically on the ground plane. It is known that in a corrugated structure, the propagation constant changes depending on the height and spacing (pitch) of the metal walls, and surface waves propagate when corrugations having a height smaller than ¼ wavelength are arranged on the ground plane. Examples of using such surface wave propagation include a surface wave transmission line (see Patent Document 2) and a surface wave antenna (see Non-Patent Document 1). On the other hand, when the height of the corrugated wall is ¼ wavelength or more, it functions as a choke or a shield and can suppress the propagation of surface waves on the ground plane (see Non-Patent Document 2).

JP 2001-189620 A JP, 2012-239096, A

R. Elliott, "On the theory of corrugated plane surfaces," in Transactions of the IRE Professional Group on Antennas and Propagation, vol. 2, no. 2, pp. 71-81, Apr. 1954. F. Scire-Scappuzzo and SN Makarov, "A Low-Multipath Wideband GPS Antenna With Cutoff or Non-Cutoff Corrugated Ground Plane," in IEEE Transactions on Antennas and Propagation, vol. 57, no. 1, pp. 33-46, Jan. 2009.

  The Yagi-Uda monopole array antenna can increase the horizontal gain as the number of directors increases, but the total length of the antenna increases accordingly.

  Further, in the corrugated line of Patent Document 2 and Non-Patent Document 1, since only plane waves perpendicular to the arrangement direction of the metal walls can propagate, electromagnetic waves that radiate from a radiation source such as a monopole antenna are spread. As a result, the reflection becomes large. In that case, it is necessary to convert the electromagnetic waves that spread radially into a plane wave with an electromagnetic horn, for example, and then guide the plane wave to the corrugated line, but this leads to enlargement of the device.

  The problem to be solved by the present invention is to provide a technique for realizing a unidirectional antenna device having a high gain.

  A first aspect of the present invention includes a ground plate, a radiation element provided on the ground plate, and N (N≧2) metal bodies arranged on the ground plate along a predetermined arrangement direction from the radiation element. A convex portion, and the i+1-th (i=1 to (N-1)) convex portion in the order of decreasing distance from the radiating element has a length in the width direction orthogonal to the arrangement direction on the main plate surface. Is an antenna device that is longer than the i-th convex portion.

  According to the first aspect, it is possible to arrange N (N≧2) convex portions of the metal body on the main plate along the predetermined arrangement direction from the radiation element. Then, the length of the convex portion in the width direction orthogonal to the array direction on the main plate surface is set so as to gradually increase from the convex portion closer to the radiating element in order to form a radio wave waveguide. be able to. According to this, the gain in the array direction can be increased, and a unidirectional antenna device with high gain can be realized.

  The N convex portions may be included within a central angle of 90 degrees with respect to the radiating element in a plan view seen from a direction orthogonal to the main plate surface.

  Thereby, the N convex portions can be accommodated within a central angle of 90 degrees with respect to the radiating element in a plan view seen from a direction orthogonal to the base plate surface.

  The projecting portion may have a projecting shape facing the radiating element in a plan view viewed from a direction orthogonal to the main plate surface.

  Thereby, the shape of each convex portion in a plan view can be a convex shape toward the radiating element. The convex shape may be, for example, an arc shape or a V shape.

  The N may be 3 or more.

  This makes it possible to form a waveguide by arranging three or more convex portions.

  The base plate may have an inclined surface.

  Accordingly, even when the base plate has an inclined surface, by providing N convex portions in the arrangement direction along the inclined surface, the same effect as any of the above can be obtained. The inclined surface includes a flat inclined surface with a constant gradient, a curved inclined surface with a continuous gradient change, and a curved inclined surface with a continuous gradient change.

  The base plate may further include a reflector provided on the opposite side of the N convex portions with the radiating element interposed therebetween.

  As a result, it is possible to realize an antenna device including a reflector and further improve the gain in the array direction.

  The N convex portions may be formed by a plurality of groove-shaped portions provided on the base plate, in which a height from the base plate surface in the arrangement direction relatively changes.

  This makes it possible to provide a plurality of groove-shaped portions on the base plate to form N convex portions.

  A convex portion of a plurality of metal bodies arranged on the base plate along the arrangement direction following the N convex portions, wherein the length in the width direction is equal to that of the N convex portions. You may further provide the some convex part below the length of the said N direction of the convex part of the said width direction.

  This makes it possible to provide a waveguide in which a plurality of convex portions whose length in the width direction is equal to or less than the length of the N-th convex portion in the width direction are arranged subsequent to the N convex portions. ..

  A second aspect of the present invention is a housing installed in a predetermined position of a vehicle in a predetermined direction, and any one of the above antenna devices built in the housing, wherein the housing is provided at the predetermined position. An in-vehicle antenna device, comprising: an antenna device that is installed at a position where the arrangement direction of the antenna devices is a specified direction with respect to the vehicle when installed in the predetermined direction.

  According to the second aspect, it is possible to install the antenna device having the same effect as any of the above in the vehicle such that the array direction of the convex portions is the specified direction with respect to the vehicle. The specified direction is defined as a communication direction based on the vehicle, such as the front direction of the vehicle.

The perspective view of an antenna device. The top view of the antenna device of FIG. The side view of the antenna device of FIG. The perspective view which shows the structural example of the antenna device in a comparative example. The figure which shows the directivity pattern of the ground plane direction measured about the antenna device of embodiment. The figure which shows the directivity pattern in the main plate direction measured about the antenna device of a comparative example. The perspective view which shows the structural example of the antenna device in a 1st modification. The perspective view which shows the structural example of the antenna device in a 2nd modification. The perspective view which shows the structural example of the antenna device in a 3rd modification. The perspective view which shows the structural example of the antenna device in a 4th modification. The perspective view which shows the structural example of the antenna device in a 5th modification. The figure which shows the structural example of the vehicle-mounted antenna apparatus in a 6th modification. The figure which shows the structural example of the vehicle-mounted antenna apparatus in a 7th modification. The figure which shows the structural example of the antenna device incorporated in the vehicle-mounted antenna device of the 7th modification. A structural perspective view of a Yagi-Uda monopole array antenna.

  Hereinafter, an example of a preferred embodiment of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, and modes to which the present invention is applicable are not limited to the following embodiments. In the description of the drawings, the same parts are designated by the same reference numerals.

  First, in this embodiment, the direction is defined as follows. The X-axis direction is the direction of the waveguide 60 that is the “arrangement direction” in which the metal bodies 50 that are convex portions are arranged, and the direction perpendicular to the plate surface of the metal base plate 1 is the Z-axis direction. Is the Y-axis direction. The X-axis positive direction is the direction toward the side where the metal bodies 50 of the director 5 are arranged when viewed from the radiator 3, and the Z-axis positive direction is the metal body 50 when viewed from the metal base plate 1. The direction is toward the designated side. In order to make it easy to understand the directions of the three orthogonal axes, reference directions indicating directions parallel to the respective axial directions are added to the drawings. It is shown only for reference of directions, and the intersection of the reference directions shown in each drawing does not mean the origin of coordinates. The coordinate origin of the three orthogonal axes is the installation position of the radiator 3 on the metal base plate 1.

  FIG. 1 is a perspective view showing a configuration example of an antenna device 100 according to this embodiment. 2 is a plan view of the antenna device 100 of FIG. 1 with the metal ground plane 1 as a plane (XY plane viewed from the Z-axis positive direction), and FIG. 3 is the antenna device. It is a side view of 100. As shown in the drawings, the antenna device 100 of the present embodiment includes a flat metal base plate (base plate) 1, a radiator 3, a director 5, and a reflector 7 installed on the metal base plate 1, Equipped with.

  The radiator 3 is provided as a radiating element on the ground plane and transmits or receives a radio signal having a predetermined frequency (hereinafter, referred to as “operating frequency”). In the present embodiment, a monopole antenna is used as the radiator 3, the height of the radiator 3 is 2.5 [mm], and the operating frequency thereof is, for example, 28.5 [GHz] (one wavelength is about 10.5 [ mm]). Not only a monopole antenna, but also a patch antenna, a horn antenna, or the like can be used.

  The director 5 forms a waveguide 60 of a radio wave transmitted or received by the antenna device 100 along an array direction (X-axis positive direction) that is a direction away from the radiator 3. In the present embodiment, the X-axis positive direction, which is the side opposite to the reflector 7 with the radiator 3 interposed, is the array direction. Then, the director 5 is configured to include, on the metal base plate 1, N (N≧2) convex portions of the metal bodies 50 arranged in the arrangement direction. The convex portions of the N metal bodies 50 constitute a kind of corrugated structure. In the present embodiment, the director 5 is configured by providing N metal bodies 50, which are N convex portions, on the metal base plate 1. Specifically, the director 5 has N (N≧2) metal bodies 50 each of which is a trapezoidal columnar shape in plan view (see FIG. 2, which is a plan view). The N convex portions are arranged on the metal base plate 1 by arranging the metal bodies 50 on the metal base plate 1 side by side in the arrangement direction to be the waveguides 60.

  The planar view shape of the metal body 50 is not limited to the trapezoidal shape illustrated, but may be a rectangular shape. The cross-sectional shape of the metal body 50 parallel to the XZ plane is not limited to the rectangular shape, but may be a semicircular shape, a trapezoidal shape, a triangular shape, or the like.

Here, the propagation velocity v of the radio wave propagating through the corrugated waveguide 60 is represented by the following equation (1) using the angular frequency ω, and is the thickness t which is the length of each metal body 50 in the X-axis direction. It is also known that the propagation speed c in vacuum becomes smaller depending on the distance p between the adjacent metal bodies 50.

  Therefore, the relationship of Expression (1) is used as a predetermined rule, and the optimum values of the thickness t, the height h, and the interval p are set based on the size of the antenna, the required gain, etc., based on the frequency used. .. However, the height h is set to be less than a quarter wavelength. Further, the number of the metal bodies 50 may be two or more (N≧2), but the gain is improved by increasing the number, so three or more (N≧3) are preferable in consideration of the size of the antenna and the like. Is. As an example, if the operating frequency is 28.5 [GHz], for example, the thickness t is 1.8 [mm], the height h is 1.6 [mm], and the interval p is 2. It is considered to be 8 [mm]. Further, the number of metal bodies 50 is shown as 10 (N=10) in FIG. 1 and the like.

  Next, the width w of each metal body 50 (50-1 to 50-10) is set to a different length. The width w is a length in the width direction of the metal body 50 when the Y-axis direction orthogonal to the arrangement direction of the metal bodies 50 that are convex bodies on the base plate surface of the metal base plate 1 is the width direction of the metal body 50. As for the width w of each metal body 50, the width w of the (i+1)th (i=1 to (N−1)) metal body 50 counted from the side close to the radiator 3 is the i-th metal body 50. It is set longer than the width. That is, each metal body 50 is configured such that its width w becomes gradually longer (wider) from the radiator 3 side along the arrangement direction (X-axis positive direction). Further, each metal body 50 is a radiation element that is a radiation element in a plan view (see FIG. 2, which is a plan (XY plane) view) viewed from a direction (Z-axis positive direction) orthogonal to the ground plane of the metal ground plane 1. It is preferable that the central angle θ with respect to the position of the container 3 be within 90 degrees.

  In this embodiment, for example, the angle θ is set to about 20 degrees. The width w of each metal body 50 is, for example, 1 [mm] for the metal body 50-1 and 2 [mm] for the metal body 50-2, in order from the one end side of the waveguide 60 closest to the radiator 3. The body was set to be gradually longer such as 3 [mm], and the width w of the metal body 50-10 at the other end of the waveguide 60 was set to 10.5 [mm].

  The reflector 7 is provided on the metal base plate 1 on the side opposite to the director 5 having the N metal bodies 50 with the radiator 3 interposed therebetween, and is opposite to the arrangement direction of the N metal bodies 50. It is located in the extension direction (X-axis negative direction). The reflector 7 is composed of one or a plurality of metal walls 70 (70-1, 70-2) having a height of 1/4 wavelength or more from the metal base plate 1. In the present embodiment, the metal wall 70 has a substantially semi-arcuate shape in plan view (see FIG. 2, which is a plan view), and is arranged so as to surround the rear in the radial direction when viewed from the radiator 3. To be done. Further, two metal walls 70 having different radii are installed side by side with a predetermined installation interval. If the operating frequency is 28.5 [GHz], the height of each metal wall 70-1, 70-2 is 3.5 [mm], and the installation interval is 2.5 [mm]. You can The number of the metal walls 70 may be one, or may be three or more. Further, although the reflection characteristics are superior or inferior, the shape in plan view may be a rectangular shape instead of a semi-arcuate shape. Further, the antenna device 100 without the reflector 7 may be configured.

  In the antenna device 100 of the present embodiment, for example, when transmitting a radio wave, a radio wave is transmitted (radiated) from the radiator 3 and enters the waveguide 5, and a surface wave is generated from one end side of the waveguide 60. Propagate to the other end. The radio wave propagating to the other end side further propagates through, for example, an external waveguide (transmission path) or free space as a medium. In the antenna device 100 of the present embodiment, the N metal bodies 50 forming the waveguide 5 form the waveguide 60 such that the width of the protrusion of the corrugated structure gradually increases from the radiator 3 side. Therefore, the director 5 acts as a lens to delay the phase of a part of the radio wave (spherical wave) radially spread from the radiator 3, and thus the spherical wave can be shaped into a plane wave and emitted. it can. Since the gain in the array direction (X-axis positive direction) can be increased compared to other directions, the antenna functions as a unidirectional antenna.

  Here, as shown in FIG. 4, for comparison, an antenna device 100a was prepared in which the director 5a was configured using the prismatic metal body 50a having the same width in the Y-axis direction. Then, with respect to the antenna device 100 of the present embodiment and the antenna device 100a of the comparative example shown in FIG. 4, directivity patterns in the ground plane direction (XY plane) were measured. FIG. 5 shows a directivity pattern in the direction of the ground plane measured for the antenna device 100 of this embodiment. Further, FIG. 6 shows a directivity pattern in the direction of the ground plane measured for the antenna device 100a of the comparative example. Comparing FIG. 5 and FIG. 6, the antenna device 100 of the present embodiment has a higher gain in the arrangement direction (X-axis positive direction) than the antenna device 100a of the comparative example, and is constant with the X-axis positive direction as the center. It can be seen that a gain of 10 [dBi] or more is obtained for the azimuth angle of.

  As described above, according to the antenna device of the present embodiment, a unidirectional antenna device with high gain can be realized.

  The mode to which the present invention is applicable is not limited to the above-described embodiment, and constituent elements can be appropriately added, omitted, or changed.

[First Modification]
For example, in the above-described embodiment, an example in which the metal wall 70 forming the reflector 7 has a semicircular arc shape as a plan view (see FIG. 2 and the like), but the shape of the metal wall 70 is not particularly limited. FIG. 7: is a perspective view which shows the structural example of the antenna device 100b in a 1st modification. In FIG. 7, the same components as those in the above embodiment are denoted by the same reference numerals.

  In this modification, the reflector 7b is composed of a plurality of prismatic metal rods 70b. A plurality of metal rods 70b are arranged in an arc shape so as to surround the radiator 3 on the side opposite to the radiation direction when viewed from the radiator 3, and are erected on the metal base plate 1. The number of the metal rods 70b may be one or may be two or more, and the number thereof is not particularly limited. Further, the array shape may be a straight line shape parallel to the metal body 50 instead of the arc shape.

[Second Modification]
Further, in the above-described embodiment, an example in which the width w of all the metal bodies 50 forming the director 5 is different is shown, but a part of the width may be changed. However, even in that case, the number N (N≧2) of the convex portions of the metal body 50 close to the radiator 3 is counted as i+1th (i=1 to 1) from the side closer to the radiator 3. The width w of (N-1)) is set to be longer than the width of the i-th metal body 50. Then, following the convex portions of the N metal bodies 50, a plurality of convex portions whose width w is equal to or less than the width w of the Nth metal body 50 (for example, the convex portions of the metal body 50c in FIG. 8). ) May be arranged in the arrangement direction (X-axis positive direction).

  FIG. 8: is a perspective view which shows the structural example of the antenna device 100c in a 2nd modification. In FIG. 8, the same components as those in the above embodiment are denoted by the same reference numerals. In the antenna device 100c of the present modification, the director 5c includes a portion forming the first waveguide 601 whose width is gradually widened from the radiator 3 side in the same manner as in the above-described embodiment, and the first waveguide 601. And a portion forming a second waveguide 603 for propagating a radio wave made a plane wave in the waveguide 601. Each metal body 50c forming the portion of the second waveguide 603 has substantially the same width as the widest metal body 50 in the portion of the first waveguide 601. Also in the antenna device 100c of this modification, the same effect as that of the above-described embodiment can be obtained. The width of each metal body 50c forming the portion of the second waveguide 603 may be equal to or less than the width of the widest metal body 50 in the portion of the first waveguide 601.

[Third Modification]
Further, in the above-described embodiment, the flat metal base plate 1 is illustrated (see FIG. 1 and the like), but the same applies even when the base plate is not flat and a part or all of the waveguide is inclined. Is applicable to. The inclined surface may be a flat inclined surface with a constant gradient, a curved inclined surface with a continuous gradient change, or a curved inclined surface with a continuous gradient change. ..

  FIG. 9 is a perspective view showing a configuration example of an antenna device 100d in the third modified example. In FIG. 9, the same components as those in the above embodiment are denoted by the same reference numerals. As shown in FIG. 9, the metal base plate 1d of the antenna device 100d of the present modification has a shape in which the metal body 50 is arranged and the portion forming the waveguide 60 has the inclined surface 10d.

  Similarly to the above embodiment, also in the antenna device 100d of this modification, the transmitted or received radio wave propagates as a surface wave along the waveguide 60. Therefore, even when the metal base plate 1d has an inclined surface and a part of the waveguide 60 is inclined, the director 5 may be provided along the inclined surface. That is, by setting the shape and size of the metal body 50 in the same manner as in the above-described embodiment and arranging the metal bodies 50 at the intervals p set in the same manner, the same effect as in the above-described embodiment is obtained.

  The slope here is not limited to the slope of the uphill shown in FIG. 9, but may be the slope of the downhill, or may include the slope of both the uphill and the downhill. Specifically, a part of the waveguide may be raised and raised, or may be recessed like a mortar, and the inclination of the waveguide is not particularly affected. Only by propagating the radio wave along the direction of the ground plane, the effects of the above-described embodiment can be similarly exhibited. Therefore, it is possible to realize a unidirectional antenna device having a high gain in the arrangement direction (X-axis positive direction) without selecting the installation location.

[Fourth Modification]
Further, in the above embodiment, the planar view shape (see FIG. 2) of the metal body 50 is a trapezoidal shape, and an example of a linear shape in the Y-axis direction is shown (see FIG. 1 and the like). The shape of the metal body 50 in the Y-axis direction may not be a linear shape, but may be a shape formed in a convex shape toward the radiator 3.

  FIG. 10: is a perspective view which shows the structural example of the antenna device 100e in this 4th modification. In FIG. 10, the same components as those in the above embodiment are denoted by the same reference numerals. As shown in FIG. 10, in the antenna device 100e of the present modification, the planar view shape of each metal body 50e forming the director 5e is a convex curved shape (or an arc shape) toward the radiator (radiating element) 3. It can be said that). Further, it may be a V-shaped convex shape instead of the curved shape. In the case of a curved shape or a V shape, the length in the width direction of the metal body 50e, which is the convex portion forming the waveguide 5, may be a length along the curved shape or the V shape. Also in the antenna device 100e of this modification, the same effect as that of the above-described embodiment can be obtained.

[Fifth Modification]
In addition, a plurality of groove-shaped portions whose width w is equal to or less than the width w of the N-th metal body 50 (for example, in the figure Alternatively, the eleven groove-shaped portions 8i) may be arranged in the arrangement direction (X-axis positive direction).

  FIG. 11: is a perspective view which shows the structural example of the antenna device 100i in a 5th modification. In FIG. 11, the same components as those in the above embodiment are denoted by the same reference numerals. In the antenna device 100i of the present modification, the width of the metal body 50 is gradually widened from the radiator 3 side in the same manner as in the above embodiment, and the portion of the first waveguide 601i constituting the waveguide 5 is provided. And a portion forming a second waveguide 603i in which the groove-shaped portions 8i are arranged for propagating a radio wave made a plane wave in the first waveguide 601i. Each groove-shaped portion 8i forming the portion of the second waveguide 603i has substantially the same width as the widest metal body 50 in the portion of the first waveguide 601i.

  The metal base plate 1i of the antenna device 100i of the present modification has a recess 111i for disposing the radiator 3 and the director 5 in the center, and the disposing portion of the director 5 on the bottom surface thereof ( The portion of the first waveguide 601i in which the metal body 50 is arranged has a shape having a downward slope toward the radiator 3. In addition, the shape of the wall portion 113i of the concave portion 111i, which is the rear side in the radial direction when viewed from the radiator 3, is substantially semicircular in plan view (the XY plane viewed from the Z-axis positive direction), and this wall portion 113i is formed. Functions as a reflector.

  Also in the antenna device 100i of this modification, the same effect as that of the above-described embodiment can be obtained. The width of each groove 8i forming the portion of the second waveguide 603i may be less than or equal to the width of the widest metal body 50 in the portion of the first waveguide 601i.

[Sixth Modification]
Further, in the above embodiment, the operating frequency is 28.5 [GHz], but the operating frequency is not limited to this and may be 10 [GHz] or 30 [GHz]. However, if the operating frequency is small, the size of the device will increase in order to secure a height of 1/4 wavelength or more. Therefore, considering the height from the ground plane required for reflectors and radiators, 20 [GHz] It is preferable to apply the antenna device of this embodiment to the above operating frequencies. Specifically, it can be applied to, for example, a radar or sensor device mounted in an aircraft or a vehicle, a repeater device such as a wireless LAN or 5G installed in a vehicle, an antenna device of a reflector device, or the like. Further, the present invention can be applied to a wireless LAN or a small base station for microwave/millimeter wave communication such as 5G, a repeater device, an antenna device of a reflector device, etc., which is installed on an indoor wall surface/ceiling surface, an outdoor wall surface, or the like.

  FIG. 12 is a diagram showing an example of a vehicle-mounted antenna device 10 in which the antenna device 100 is applied to a vehicle 200. Here, the front-rear, left-right, and up-down directions of the vehicle-mounted antenna device 10 are the same as the front-rear, left-right, and up-down directions of the vehicle 200 when installed on the vehicle 200.

  As shown in FIG. 12, a vehicle-mounted antenna device 10 of the present modification is configured such that the antenna device 100 of the above-described embodiment is built in a housing 11 and is oriented in a predetermined direction on a rear upper surface of a roof 201 of a vehicle 200 which is a passenger car. Will be installed in. The vehicle-mounted antenna device 10 is not limited to the antenna device 100 of the above-described embodiment, and any of the antenna devices 100b, 100c, 100d, and 100e of the first modification to the fourth modification or an antenna device combining these configurations. It can also be configured by incorporating.

  Specifically, the outer shape of the vehicle-mounted antenna device 10 has a fin shape that rectifies traveling wind during traveling and reduces fluid resistance, and the front is tapered and the height increases toward the rear. It is designed. Then, the vehicle-mounted antenna device 10 is installed at a predetermined position (the upper rear surface of the roof 201) of the vehicle 200 in such a direction that the narrower side is the front and the higher side is the rear.

  The antenna device 100 is arranged in the housing 11 so as to have a predetermined orientation when the vehicle-mounted antenna device 10 is installed in a predetermined position of the vehicle 200. Specifically, the direction in which the vehicle 200 transmits or receives a radio wave using the antenna device 100 is set as a predetermined direction A1 with respect to the vehicle 200 as an assumed direction. The position of the vehicle 200 in which the antenna device 100 is installed is also determined. Therefore, the position and orientation in which the antenna device 100 is incorporated in the housing 11 are set so that the arrangement direction (X-axis positive direction) when the antenna device 100 is installed in the vehicle 200 is the specified direction A1. ing.

[Seventh Modification]
Further, the application to the vehicle is not limited to the fin-shaped vehicle-mounted antenna device 10 shown in the sixth modification. FIG. 13 is a diagram showing a vehicle-mounted antenna device 10f of the present modification, and FIG. 14 is a perspective view showing a configuration example of one antenna device 100f-1 included in the vehicle-mounted antenna device 10f. Here, the front-rear, left-right, and up-down directions of the vehicle-mounted antenna device 10 are the same as the front-rear, left-right, and up-down directions of the vehicle 200f when installed in the vehicle 200f.

  The vehicle-mounted antenna device 10f of the present modification is configured such that two antenna devices 100f (100f-1, 100f-2) are built in the housing 11f, and are installed near the center of the roof 201f of the vehicle 200f. The antenna device 100f of this modification has the same configuration as the antenna device 100d of the third modification. The antenna device 100d of the third modified example is configured by incorporating an antenna device in which the configurations of the antenna devices 100b, 100c, and 100e of any one of the first modified example, the second modified example, and the fourth modified example are combined. You can also

  Specifically, the vehicle-mounted antenna device 10f is installed in a predetermined direction in a concave portion 203f having an inclined surface near the center of the roof 201f of the vehicle 200f. Then, the two antenna devices 100f are provided with a metal base plate 1f that is partially inclined so as to follow the shape of the recess 203f, as shown enlarged in FIG. The inclined surface does not have to be a flat surface and includes a curved surface. That is, when the shape of the recess includes a curved surface, the shape of the metal base plate 1f can be a shape along the curved surface.

  Further, the two antenna devices 100f have a common reflector 7f arranged near the center on the metal base plate 1f, and the radiators 3f of the respective antenna devices 100f are arranged in front and behind with the reflector 7f interposed therebetween. .. Then, on the side opposite to the reflector 7f across the radiator 3f, the metal bodies 50f forming the respective waveguides 5f are arranged in the front-rear direction. More specifically, the length of the metal body 50f in the width direction is gradually widened from the radiator 3f side to form the waveguide 60. When transmitting a radio wave, the radio wave from the radiator 3 is guided as a plane wave along the surface of the roof 201f and emitted in the front-rear direction. According to the vehicle-mounted antenna device 10f having this configuration, each component of the antenna device 100f can be arranged in the recess 203f formed in the roof 201f. Since the height of the antenna device 100f can be suppressed to be low, it is possible to provide an antenna device having excellent aerodynamic characteristics without hindering the shape (design) of the vehicle body.

[Eighth Modification]
Further, in the above embodiment, an example of the waveguide 5 in which N (N≧2) metal bodies 50 are arranged on the metal base plate 1 to form N convex portions is shown. If the waveguide 5 has a shape in which the height with respect to the ground plane is regularly changed in the arrangement direction (X-axis positive direction), the same operational effect as that of the above-described embodiment can be exhibited. Therefore, the metal base plate 1 between the adjacent metal bodies 50 may be formed as a recess so that the metal base plate 1 and the waveguide 5 are formed in a corrugated shape. The metal body 50 may be omitted, and a plurality of groove-shaped recesses may be provided in parallel in the metal base plate 1 to configure the metal base plate 1. In that case, the concave portions are groove-shaped, but the concave portions are relatively convex portions. Therefore, with respect to the N (N≧2) convex portions formed relatively, the i+1th (i=1 to (N−1)) convex portions in the width direction are arranged in the order of increasing distance from the radiating element. The length may be longer than the length of the i-th convex portion in the width direction.

100, 100b, 100c, 100d, 100e, 100f, 100i... Antenna device 1, 1d, 1f, 1i... Metal base plate 3, 3f... Radiator 5, 5c, 5e, 5f... Waveguide 50, 50c, 50e, 50f Metal body 60... Waveguide 601... 1st waveguide 603... 2nd waveguide 7, 7b, 7f... Reflector 70, 70b... Metal wall 8i... Groove-shaped part 10, 10f... Vehicle-mounted antenna device 200, 200f... Vehicle A1... Specified direction

Claims (9)

The ground plane,
A radiating element provided on the ground plane,
N (N≧2) convex portions of metal bodies arranged on the base plate along a predetermined arrangement direction from the radiating element,
Equipped with
The i+1-th (i=1 to (N-1)) convex portion in the order of decreasing distance from the radiating element has an i-th convex portion whose length in the width direction orthogonal to the arrangement direction on the main plate surface. Longer,
Antenna device. The N convex portions fit within a central angle of 90 degrees with respect to the radiating element in a plan view seen from a direction orthogonal to the main plate surface,
The antenna device according to claim 1. The convex portion has a shape in plan view seen from a direction orthogonal to the main plate surface, and is a convex shape toward the radiating element,
The antenna device according to claim 1. The N is 3 or more,
The antenna device according to claim 1. The main plate has an inclined surface,
The antenna device according to claim 1. A reflector provided on the base plate on the side opposite to the N convex portions with the radiating element interposed therebetween;
The antenna device according to claim 1, further comprising: The N convex portions are formed by a plurality of groove-shaped portions provided on the base plate, and a height of the base plate surface in the arrangement direction relatively changes.
The antenna device according to any one of claims 1 to 6. A convex portion of a plurality of metal bodies arranged on the main plate along the arrangement direction following the N convex portions, wherein the length in the width direction is equal to that of the N convex portions. A plurality of convex portions having a length in the width direction of the N-th convex portion,
The antenna device according to claim 1, further comprising: A casing installed in a predetermined position of the vehicle in a predetermined direction,
The antenna device according to any one of claims 1 to 8, which is built in the housing, wherein the arrangement direction of the antenna devices when the housing is installed at the predetermined position in the predetermined direction. An antenna device built in a position that is a specified direction with respect to the vehicle,
An in-vehicle antenna device comprising:

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