JP7194566B2 - antenna device - Google Patents

Description

The present invention relates to an antenna device.

Radio waves can be transmitted and received in a specific direction in MIMO (Multiple-Input and Multiple-Output) transmission in wireless LAN and fifth-generation mobile communication systems (5G), including radar and sensor devices installed in aircraft and vehicles. The role of a compact, unidirectional antenna that can

A Yagi-Uda monopole array antenna, for example, is known as one of low profile directivity antennas in which radiating elements are linearly arranged on a metal base plate (see, for example, Patent Document 1). FIG. 15 is a structural perspective view of the Yagi-Uda monopole array antenna 100h, which includes one rod-shaped radiator 3h and one rod-shaped reflector 7h, and a plurality of (10 in the illustrated example) metal antennas. A director 5h composed of a body 50h is arranged on the base plate 1h in a straight line at predetermined intervals. The principle of operation of the Yagi-Uda monopole array antenna is well known. It is intended to increase

On the other hand, from a different point of view, the arrangement of waveguides in the Yagi-Uda monopole array antenna can be regarded as a type of so-called corrugated structure in which metal walls are periodically arranged on the ground plane. It is known that the propagation constant of the corrugated structure varies depending on the height and interval (pitch) of the metal walls, and surface waves propagate when corrugated structures with a height smaller than 1/4 wavelength are arranged on the ground plane. Examples of using surface wave propagation include a surface wave transmission line (see Patent Document 2) and a surface wave antenna (see Non-Patent Document 1). Conversely, when the height of the corrugated wall is set to 1/4 wavelength or more, it functions as a choke or a shield, and can suppress surface wave propagation on the ground plane (see Non-Patent Document 2).

Japanese Patent Application Laid-Open No. 2001-189620 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 S. N. 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.

Although the Yagi-Uda monopole array antenna can increase the horizontal gain by increasing the number of waveguides, the overall length of the antenna increases accordingly.

In addition, the corrugated lines of Patent Document 2 and Non-Patent Document 1 can only propagate plane waves perpendicular to the direction in which the metal walls are arranged. the reflection becomes large. In that case, it is necessary to first convert the radially spreading electromagnetic wave into a plane wave by means of, for example, an electromagnetic horn, and then lead it to the corrugated line, which leads to an increase in the size of the apparatus.

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

A first aspect of the present invention comprises a base plate, a radiation element provided on the base plate, and N (N≧2) metal bodies arranged on the base plate along a predetermined arrangement direction from the radiation element. and the i+1-th (i=1 to (N−1)) convex portion having the shortest distance from the radiating element has a length in the width direction orthogonal to the arrangement direction on the ground plane. 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 bodies on the ground plane along a predetermined arrangement direction from the radiating element. Then, the length of the convex portion in the width direction perpendicular to the arrangement direction on the ground plane surface is set so that the length of the convex portion becomes longer in order from the convex portion closer to the radiating element, thereby forming a waveguide for radio waves. be able to. According to this, the gain in the arrangement direction can be increased, and a unidirectional antenna device with high gain can be realized.

The N convex portions may be arranged within a central angle of 90 degrees with respect to the radiating element in plan view in a direction orthogonal to the ground plane.

As a result, the N convex portions can be accommodated within a central angle of 90 degrees with respect to the radiating element in a plan view viewed in a direction perpendicular to the ground plane.

The convex portion may have a convex shape directed toward the radiating element when viewed from a direction orthogonal to the ground plane.

As a result, the shape of each convex portion in a plan view can be a convex shape facing the radiating element. The convex shape may be, for example, arc-shaped or V-shaped.

The N may be 3 or more.

Thereby, a waveguide can be formed by arranging three or more convex portions.

The base plate may have an inclined surface.

Accordingly, even if the base plate has an inclined surface, by providing N convex portions in the arrangement direction along the inclined surface, it is possible to obtain the same effect as any of the above. The inclined surface includes a flat inclined surface with a constant gradient, a curved inclined surface with an intermittently changing gradient, and a curved inclined surface with a continuously changing gradient.

A reflector may be provided on the ground plate on the opposite side of the radiating element from the N convex portions.

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

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

Thereby, N convex portions can be formed by providing a plurality of groove portions on the base plate.

A plurality of metal convex portions arranged on the base plate along the arrangement direction following the N convex portions, wherein the length in the width direction is equal to the length of the N convex portions. It may further include a plurality of convex portions whose length in the width direction is equal to or less than the N-th convex portion among them.

As a result, following the N convex portions, a waveguide can be provided in which a plurality of convex portions whose length in the width direction is equal to or less than the length in the width direction of the N-th convex portion are arranged. .

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

According to the second aspect, the antenna device having the same effect as any of the above can be installed in the vehicle so that the arrangement direction of the convex portions is in the specified direction with respect to the vehicle. The prescribed direction is defined as a communication direction with the vehicle as a reference, such as the forward direction of the vehicle.

1 is a perspective view of an antenna device; FIG. FIG. 2 is a plan view of the antenna device of FIG. 1; FIG. 2 is a side view of the antenna device of FIG. 1; The perspective view which shows the structural example of the antenna apparatus in a comparative example. FIG. 4 is a diagram showing a directivity pattern in the direction of the ground plane measured for the antenna device of the embodiment; FIG. 5 is a diagram showing a directivity pattern in the direction of the ground plane measured for an antenna device of a comparative example; The perspective view which shows the structural example of the antenna apparatus in a 1st modification. The perspective view which shows the structural example of the antenna apparatus in a 2nd modification. The perspective view which shows the structural example of the antenna apparatus in a 3rd modification. The perspective view which shows the structural example of the antenna apparatus in a 4th modification. The perspective view which shows the structural example of the antenna apparatus 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 which the vehicle-mounted antenna device of a 7th modification incorporates. Structural perspective view of the Yagi-Uda monopole array antenna.

An example of a preferred embodiment of the present invention will be described below with reference to the drawings. The present invention is not limited by the embodiments described below, nor is the form to which the present invention can be applied limited to the following embodiments. Moreover, in the description of the drawings, the same reference numerals are given to the same parts.

First, in this embodiment, directions are defined as follows. The direction of the waveguide 60, which is the "arrangement direction" in which the metal bodies 50 forming the convex portions are arranged, is defined as the X-axis direction, the direction perpendicular to the plate surface of the metal base plate 1 is defined as the Z-axis direction, and the direction orthogonal to these directions. is the Y-axis direction. The positive direction of the X-axis is the direction toward the side where the metal bodies 50 of the waveguide 5 are arranged when viewed from the radiator 3, and the positive direction of the Z-axis is the direction where the metal bodies 50 are provided when viewed from the metal base plate 1. direction toward the side that was hit. In order to make it easier to understand the directions of the three orthogonal axes, a reference direction indicating a direction parallel to each axis is added to each figure. It is shown only for reference of the direction, and the intersection of the reference directions shown in each figure does not mean the coordinate origin. 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 (XY plane seen from the positive Z-axis direction) of the antenna device 100 of FIG. 1 with the metal base plate 1 as a plane, and FIG. FIG. 100 is a side view of FIG. As shown in each figure, the antenna device 100 of this 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, Prepare.

The radiator 3 is provided as a radiation element on the ground plane, and transmits or receives radio signals of a predetermined frequency (hereinafter referred to as "operating frequency"). In this embodiment, a monopole antenna is used as the radiator 3, the height of the radiator 3 is 2.5 [mm], and the operating frequency is, for example, 28.5 [GHz] (one wavelength is about 10.5 [ mm]). For example, a patch antenna, a horn antenna, or the like can be used instead of a monopole antenna.

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

The planar view shape of the metal body 50 is not limited to the illustrated trapezoidal shape, and may be a rectangular shape. Also, the cross-sectional shape of the metal body 50 parallel to the XZ plane is not limited to a rectangular shape, and 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 the thickness t Also, it is known that the propagation speed c in a vacuum becomes smaller depending on the interval p between the adjacent metal bodies 50 .

Therefore, using the relationship of formula (1) as a predetermined rule, the optimal values for the thickness t, height h, and spacing p are obtained and set based on the size of the antenna, the required gain, etc., based on the frequency to be used. . However, the height h is less than 1/4 wavelength. In addition, the number of metal bodies 50 may be two or more (N≧2), but since the gain improves as the number increases, three or more (N≧3) is preferable in consideration of the size of the antenna and the like. is. For example, if the operating frequency is 28.5 [GHz], the thickness t is 1.8 [mm], the height h is 1.6 [mm], and the interval p is 2.5 [mm]. It is conceivable to set it to 8 [mm]. Also, the number of metal bodies 50 is illustrated as ten (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 the width direction length of the metal bodies 50 when the Y-axis direction orthogonal to the arrangement direction of the metal bodies 50 which are convex bodies on the ground plane of the metal ground board 1 is the width direction of the metal bodies 50 . The width w of each metal body 50 is the i+1-th (i=1 to (N−1)) metal body 50 counted from the side closer to the radiator 3 than the width w of the i-th metal body 50. 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). In addition, each metal body 50 is a radiating element, which is a radiation element, in a plan view (see FIG. 2 which is a plan (XY plane) view) viewed from a direction perpendicular to the ground plane of the metal ground plane 1 (positive direction of the Z-axis). It is preferable that the center angle .theta. with respect to the position of the vessel 3 is within 90 degrees.

In this embodiment, the angle θ is set to approximately 20 degrees, for example. The width w of each metal body 50 is, for example, 1 [mm] for the metal body 50-1, 2 [mm] for the metal body 50-2, 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 opposite side of the waveguide 5 having the N metal bodies 50 with the radiator 3 interposed therebetween, and is arranged in the direction opposite to the arrangement direction of the N metal bodies 50 . It is located in the extension direction (X-axis negative direction). This reflector 7 is composed of one or a plurality of metal walls 70 (70-1, 70-2) whose height from the metal base plate 1 is 1/4 wavelength or more. In the present embodiment, the metal wall 70 has a substantially semicircular shape in a plan view (see FIG. 2 which is a plan view), and is arranged so as to surround the rear side of the radiator 3 in the radial direction. be done. Also, two metal walls 70 having different radii are arranged 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 should be, for example, 3.5 [mm], and the installation interval should be, for example, 2.5 [mm]. can be done. One metal wall 70 may be provided, or three or more metal walls may be installed. Also, the shape in plan view may be a rectangular shape instead of a semicircular arc shape, although there are differences in reflection characteristics. Alternatively, the antenna device 100 may be configured without the reflector 7 .

In the antenna device 100 of the present embodiment, for example, in the case of transmitting radio waves, radio waves are transmitted (radiated) from the radiator 3, enter the waveguide 5, and form a surface wave from one end of the waveguide 60. It propagates to the other end side. The radio wave propagated to the other end further propagates through, for example, an external waveguide (transmission line) or free space as a medium. In the antenna device 100 of the present embodiment, the waveguide 60 is formed by the N metal bodies 50 forming the waveguide 5 such that the width of the projection of the corrugated structure gradually widens from the radiator 3 side. Therefore, the waveguide 5 functions like a lens that delays the phase of a portion of the radio waves (spherical waves) radially spreading from the radiator 3, so that the spherical waves can be shaped into plane waves and emitted. can. Since the gain in the arrangement direction (the positive direction of the X axis) can be increased compared to other directions, it acts as a unidirectional antenna.

Here, as shown in FIG. 4, for comparison, an antenna device 100a was prepared in which a director 5a was constructed using prismatic metal bodies 50a all having the same width, which is the length in the Y-axis direction. Then, directivity patterns in the ground plane direction (XY plane) were measured for each of the antenna device 100 of this embodiment and the antenna device 100a of the comparative example shown in FIG. FIG. 5 shows the directivity pattern in the direction of the ground plane measured for the antenna device 100 of this embodiment. FIG. 6 shows the directivity pattern in the direction of the ground plane measured for the antenna device 100a of the comparative example. Comparing FIGS. 5 and 6, the antenna device 100 of the present embodiment has an improved gain in the array direction (positive direction of the X-axis) compared to the antenna device 100a of the comparative example, and has a constant gain around the positive direction of the X-axis. It can be seen that a gain of 10 [dBi] or more is obtained in the azimuth angle of .

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

The form to which the present invention can be applied is not limited to the above-described embodiment, and the addition, omission, and change of constituent elements can be applied as appropriate.

[First modification]
For example, in the above-described embodiment, the metal wall 70 forming the reflector 7 has a semi-arc shape in plan view (see FIG. 2, etc.), but the shape of the metal wall 70 is not particularly limited. FIG. 7 is a perspective view showing a configuration example of an antenna device 100b in the first modified example. In FIG. 7, the same reference numerals are given to the same configurations as in the above-described embodiment.

In this modification, the reflector 7b is composed of a plurality of prismatic metal rods 70b. A plurality of metal rods 70b are erected on the metal base plate 1 so as to surround the radiator 3 on the opposite side of the radiator 3 in the radial direction. The number of metal rods 70b may be one, or two or more, and the number is not particularly limited. Also, the arrangement shape may be a linear shape parallel to the metal body 50 instead of the circular arc shape.

[Second modification]
Moreover, although the width w of all the metal bodies 50 constituting the director 5 is different in the above-described embodiment, the width w of some of the metal bodies 50 may be changed. However, even in that case, the convex portions of the N pieces (N≧2) of the metal bodies 50 close to the radiator 3 are counted from the one closest to the radiator 3, i+1 (i=1 to The width w of (N−1)) is set longer than the width of the i-th metal body 50 . Then, following the protrusions of the N metal bodies 50, a plurality of protrusions whose width w is equal to or less than the width w of the N-th metal body 50 (for example, the protrusion of the metal body 50c in FIG. ) are arranged in the arrangement direction (X-axis positive direction).

FIG. 8 is a perspective view showing a configuration example of an antenna device 100c in a second modified example. In FIG. 8, the same reference numerals are given to the same configurations as in the above embodiment. In the antenna device 100c of this modified example, the director 5c includes a portion forming a first waveguide 601 whose width is gradually widened from the radiator 3 side in the same manner as in the above-described embodiment, and this first waveguide 601. and a portion forming a second waveguide 603 for propagating the radio wave made into a plane wave in the waveguide 601 . Each metal body 50c forming the second waveguide 603 has substantially the same width as the widest metal body 50 in the first waveguide 601 portion. Also in the antenna device 100c of this modified example, the same effects as those of the above-described embodiment can be obtained. The width of each metal body 50c forming the second waveguide 603 portion may be less than or equal to the width of the widest metal body 50 in the first waveguide 601 portion.

[Third Modification]
In addition, in the above-described embodiment, the flat metal base plate 1 is illustrated (see FIG. 1 and the like). applicable to The inclined surface may be a flat inclined surface with a constant gradient, a curved inclined surface with an intermittently changing gradient, or a curved inclined surface with a continuously changing gradient. .

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 reference numerals are assigned to the same configurations as in the above-described embodiment. As shown in FIG. 9, the metal base plate 1d of the antenna device 100d of this modified example has an inclined surface 10d at the portion where the metal bodies 50 are arranged and the waveguide 60 is formed.

In the antenna device 100d of this modified example, radio waves to be transmitted or received propagate along the waveguide 60 as surface waves, as in the above-described embodiment. Therefore, even if the metal base plate 1d has an inclined surface and a part of the waveguide 60 is inclined, the waveguide 5 may be provided along the inclined surface. That is, by setting the shape and size of the metal bodies 50 in the same manner as in the above-described embodiment and arranging the metal bodies 50 at intervals p set in the same manner, the same effects as in the above-described embodiment can be obtained.

The slope here is not limited to the uphill slope shown in FIG. 9, but may be a downhill slope, or may include both uphill and downhill slopes. Specifically, a portion of the waveguide may swell and become high, or conversely, it may be recessed in the shape of a mortar, and the steepness of the inclination is not particularly affected. The effects of the above-described embodiment are similarly exhibited only by the propagation of radio waves along the direction of the ground plane. Therefore, it is possible to realize a unidirectional antenna device having a high gain in the arrangement direction (positive direction of the X-axis) regardless of the installation location.

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

FIG. 10 is a perspective view showing a configuration example of an antenna device 100e in this fourth modification. In FIG. 10, the same reference numerals are given to the same configurations as in the above-described embodiment. As shown in FIG. 10, in the antenna device 100e of this modified example, each metal body 50e that constitutes the director 5e has a convex curved shape (or arcuate shape) toward the radiator (radiating element) 3 in plan view. can also be said). Moreover, it may be a V-shaped convex shape instead of a 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 the length along the curved shape or V shape. Also in the antenna device 100e of this modified example, it is possible to obtain the same effects as those of the above-described embodiment.

[Fifth Modification]
Further, following the convex portions of the N metal bodies 50 as exemplified in the second modification, a plurality of groove-shaped portions having a width w equal to or less than the width w of the N-th metal body 50 11 groove-shaped portions 8i) may be arranged in the arrangement direction (X-axis positive direction).

FIG. 11 is a perspective view showing a configuration example of an antenna device 100i in the fifth modified example. In FIG. 11, the same reference numerals are given to the same configurations as in the above-described embodiment. The antenna device 100i of this modified example includes a first waveguide 601i portion that forms the waveguide 5 by gradually widening the width of the metal body 50 from the radiator 3 side in the same manner as in the above-described embodiment, and a portion forming a second waveguide 603i in which the groove-shaped portions 8i are arranged for propagating the radio waves made into plane waves in the first waveguide 601i. Each groove-like 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 this modified example has a recess 111i for arranging the radiator 3 and the director 5 in the center, and the portion where the director 5 is arranged on the bottom surface ( A portion of the first waveguide 601 i where the metal bodies 50 are arranged has a shape with a downward slope toward the radiator 3 . A wall portion 113i of the concave portion 111i behind the radiator 3 in the radial direction has a substantially semicircular shape in plan view (XY plane viewed from the positive direction of the Z-axis). Acts as a reflector.

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

[Sixth Modification]
Also, in the above embodiment, the operating frequency is 28.5 [GHz], but it is not limited to this, and may be 10 [GHz] or 30 [GHz]. However, if the operating frequency is low, the device must be large enough to secure a height of 1/4 wavelength or more. It is preferable to apply the antenna device of this embodiment to the above operating frequencies. Specifically, for example, it can be applied to radar and sensor devices mounted on aircraft and vehicles, repeater devices such as wireless LAN and 5G installed on vehicles, antenna devices of reflector devices, and the like. In addition, it can be applied to small base stations, repeater devices, reflector antenna devices, etc. for wireless LAN, microwave and millimeter wave communication such as 5G installed on indoor wall surfaces, ceiling surfaces, and outdoor wall surfaces.

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

As shown in FIG. 12, the in-vehicle antenna device 10 of this modified example is constructed by incorporating the antenna device 100 of the above-described embodiment in a housing 11, and is oriented in a predetermined direction toward the rear upper surface of a roof 201 of a vehicle 200, which is a passenger car. is installed in The vehicle-mounted antenna device 10 is not limited to the antenna device 100 of the above embodiment, but may be any of the antenna devices 100b, 100c, 100d, and 100e of the first to fourth modifications, or an antenna device combining these configurations. can also be configured with a built-in

Specifically, the external shape of the in-vehicle antenna device 10 has a fin shape that rectifies the running wind during running and reduces the fluid resistance. designed. The in-vehicle antenna device 10 is installed at a predetermined position (upper rear surface of the roof 201) of the vehicle 200 with the tapered side facing forward and the tall side facing backward.

The antenna device 100 is arranged in the housing 11 so that the vehicle-mounted antenna device 10 is oriented in a predetermined direction when installed at a predetermined position in the vehicle 200 . Specifically, the direction in which vehicle 200 transmits or receives radio waves using antenna device 100 is defined as prescribed direction A1 with respect to vehicle 200 as an assumed direction. Also, the position of the vehicle 200 where the antenna device 100 is installed is determined. Therefore, the position and orientation of the antenna device 100 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 prescribed direction A1. ing.

[Seventh Modification]
Further, application to vehicles is not limited to the fin-shaped vehicle-mounted antenna device 10 shown in the sixth modification. FIG. 13 is a view showing a vehicle-mounted antenna device 10f of this 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 in-vehicle 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.

A vehicle-mounted antenna device 10f of this modified example is constructed by incorporating two antenna devices 100f (100f-1, 100f-2) in a housing 11f and installed near the center of a roof 201f of a vehicle 200f. An antenna device 100f of this modified example has the same configuration as the antenna device 100d of the third modified example. The antenna device 100d of the third modification incorporates an antenna device that combines the configurations of the antenna devices 100b, 100c, and 100e of any one of the first, second, and fourth modifications. can also

Specifically, the in-vehicle antenna device 10f is installed in a predetermined orientation in a concave portion 203f having an inclined surface near the center of the roof 201f of the vehicle 200f. 13, the two antenna devices 100f are provided with a metal base plate 1f, a part of which is inclined along the shape of the concave portion 203f. An inclined surface need not be a flat surface and includes curved surfaces. That is, when the shape of the recess includes a curved surface, the metal base plate 1f can be shaped along the curved surface.

Further, the two antenna devices 100f share a 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 the reflector 7f. . On the opposite side of the reflector 7f with the radiator 3f interposed therebetween, metal bodies 50f forming each director 5f are arranged along the front-rear direction. More specifically, the waveguide 60 is formed by gradually widening the length of the metal body 50f in the width direction from the radiator 3f side. When radio waves are transmitted, the radio waves from the radiator 3 are derived as plane waves along the surface of the roof 201f and emitted in the longitudinal direction. According to the in-vehicle antenna device 10f having this configuration, each component of the antenna device 100f can be arranged in the concave portion 203f formed in the roof 201f. Since the height of the antenna device 100f can be kept low, it is possible to provide an antenna device with excellent aerodynamic characteristics without interfering with the shape (design) of the vehicle body.

[Eighth modification]
Further, in the above-described embodiment, an example of the waveguide 5 in which N convex portions are formed by arranging N (N≧2) metal bodies 50 on the metal base plate 1 is shown. If the waveguide 5 has a shape in which the height with respect to the ground plane as a reference changes regularly in the arrangement direction (positive direction of the X-axis), it can exhibit the same effect as the above-described embodiment. Therefore, the portion of the metal base plate 1 between the adjacent metal bodies 50 may be used as a concave portion, and the uneven shape of the combination of the metal base plate 1 and the waveguide 5 may be formed in a wavy shape. The metal body 50 may be dispensed with, and the metal base plate 1 may be provided with a plurality of groove-like recesses in parallel. In that case, the recesses are groove-shaped, but there are relatively convex portions between the recesses. Therefore, among the N (N≧2) convex portions formed relatively, the width direction of the i+1-th (i=1 to (N−1)) convex portion in descending order of distance from the radiation element is The length may be longer than the length in the width direction of the i-th convex portion.

100, 100b, 100c, 100d, 100e, 100f, 100i... antenna device 1, 1d, 1f, 1i... metal base plate 3, 3f... radiator 5, 5c, 5e, 5f... director 50, 50c, 50e, 50f DESCRIPTION OF SYMBOLS Metal body 60 Waveguide 601 First waveguide 603 Second waveguide 7, 7b, 7f Reflector 70, 70b Metal wall 8i Groove 10, 10f Vehicle antenna device 200, 200f...Vehicle A1...Regulated direction

Claims (9)

a baseplate;
a radiating element provided on the ground plane;
N (N≧2) metal convex portions arranged on the ground plane along a predetermined arrangement direction from the radiating element;
with
The i+1-th (i=1 to (N−1)) convex portion in order of distance from the radiating element is the i-th convex portion whose length in the width direction perpendicular to the arrangement direction on the ground plane is the i-th convex portion. longer ,
The N convex portions fit within a central angle of 180 degrees with respect to the radiating element in a plan view viewed from a direction perpendicular to the ground plane.
antenna device. The N convex portions fit within a central angle of 90 degrees with respect to the radiating element in a plan view viewed from a direction orthogonal to the ground plane.
The antenna device according to claim 1. The convex portion has a convex shape facing the radiating element when viewed from a direction orthogonal to the ground plane.
The antenna device according to claim 1 or 2. The N is 3 or more,
An antenna device according to any one of claims 1 to 3. The base plate has an inclined surface,
The antenna device according to any one of claims 1-4. a reflector provided on the ground plate on the opposite side of the radiating element from the N convex portions;
The antenna device according to any one of claims 1 to 5, further comprising: The N convex portions are formed by relatively changing the height from the ground plate surface in the arrangement direction by a plurality of groove-shaped portions provided on the ground plate,
The antenna device according to any one of claims 1-6. A plurality of metal convex portions arranged on the base plate along the arrangement direction following the N convex portions, wherein the length in the width direction is equal to the length of the N convex portions. a plurality of convex portions whose length in the width direction is equal to or less than the N-th convex portion among them;
The antenna device according to any one of claims 1 to 7, further comprising: a housing installed in a predetermined position in a vehicle in a predetermined orientation;
9. The antenna device according to any one of claims 1 to 8, which is incorporated in the housing, wherein the arrangement direction of the antenna device when the housing is installed in the predetermined position in the predetermined orientation An antenna device built in a position where is a specified direction with respect to the vehicle;
An in-vehicle antenna device comprising:

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