JP2012054653A - Antenna device and array antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna device capable of suppressing inter-sector interference with a simple structure.SOLUTION: An antenna device includes a reflection board and at least one half-wave dipole antenna disposed thereon. The polarization direction of radio wave radiated from the at least one half-wave dipole antenna is vertical to the earth. The antenna device includes a first and a second conductors disposed along the extension direction of the at least one half-wave dipole antenna on both sides thereof. When a first face is specified as a face that is parallel to the reflection plane of the reflection board and the at least one half-wave dipole antenna is disposed thereon and a second face is specified as a face that is parallel to the reflection plane of the reflection board and the first and second conductors are disposed thereon, the second face is located outside the first face when viewed from the reflection plane of the reflection board. The first and second conductors have a first and a second slits extending from both ends of the extension direction to a central area, respectively.

Description

  The present invention relates to an antenna device and an array antenna used as a base station antenna for mobile communication, and more particularly to an antenna optimal for a plurality of sector sectors used for obtaining a horizontal plane directivity covering all 360 ° directions. The present invention relates to an apparatus and an array antenna.

In a base station antenna for mobile communication, for example, when the subscriber capacity is to be increased, it is necessary to change the half width of the radiation beam in the horizontal plane of the antenna device.
As one of the methods for changing the half-width of the radiation beam in the horizontal plane of the antenna device, in the multi-frequency shared antenna in which the half-width of the radiation beam in the horizontal plane is about 120 °, the half-width of the highest frequency is set on both sides of the existing antenna. It is known to reduce the half width of the highest frequency horizontal radiation beam by erecting a metal conductor having a length of about the wavelength. (See Patent Document 1 below)

As prior art documents related to the invention of the present application, there are the following.
JP 2006-217104 A

When a mobile communication base station has a three-sector configuration, the antennas constituting each sector are arranged at the same base station at a 120 ° separation angle. At that time, the beam width in the horizontal plane of the antenna constituting each sector is preferably a sector shape of 120 °.
However, since the antenna gain actually exists in directions other than the 120 ° direction as in the multi-frequency shared antenna described in Patent Document 1, for example, the directivity of the two antennas mainly between sectors. Duplicate characteristics. The larger the overlapping area, the greater the interference between sectors, leading to deterioration in communication quality.
As a method for solving the above-mentioned problems, a method of increasing the thickness of the antenna cover or a method of increasing the shape of the reflector is known, but these methods complicate the shape of the entire antenna. There was a problem of high costs.
The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide an antenna device that can suppress inter-sector interference with a simple structure. is there.
Another object of the present invention is to provide an array antenna that uses the antenna device described above as a vertically polarized antenna device.
The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.
(1) A reflector and at least one half-wave dipole antenna disposed on the reflector are provided, and the polarization direction of radio waves radiated from the at least one half-wave dipole antenna is relative to the ground. An antenna device in a vertical direction, wherein the first conductor and the second conductor are disposed on both sides of the at least one half-wave dipole antenna along an extension direction of the at least one half-wave dipole antenna. A surface on which the at least one half-wave dipole antenna is disposed is parallel to the reflection surface of the reflection plate and parallel to the reflection surface of the reflection plate. When the surface on which the body and the second conductor are disposed is the second surface, the second surface is located outside the first surface when viewed from the reflective surface of the reflector, The first conductor and the second conductor; The conductors each have a first slit and a second slit extending toward the central area from the two ends of the extension direction.
(2) In (1), a waveguide is disposed on the at least one half-wave dipole antenna, and a surface on which the waveguide is disposed is parallel to a reflection surface of the reflector. When the third surface is used, the third surface is located outside the first surface when viewed from the reflecting surface of the reflecting plate.

(3) In (1), the at least one half-wave dipole antenna is a pair of half-wave dipole antennas arranged at a predetermined interval on the reflector.
(4) In (3), having a waveguide disposed on the reflection surface of the reflection plate on a surface orthogonal to the reflection surface of the reflection plate and passing through the center of the pair of half-wave dipole antennas When the surface on which the director is disposed is parallel to the reflecting surface of the reflecting plate and is a third surface, the third surface is more than the second surface when viewed from the reflecting surface of the reflecting plate. Is also located outside.
(5) An array antenna comprising a first antenna device in which the polarization direction of radio waves is horizontal to the ground, and a second antenna device in which the polarization direction of radio waves is perpendicular to the ground, The second antenna device is the antenna device according to any one of (1) to (4) described above.

The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.
According to the present invention, it is possible to suppress inter-sector interference with a simple structure.

It is a perspective view which shows schematic structure of the antenna device for vertically polarized waves of Example 1 of this invention. It is the front view which looked at the antenna apparatus for vertically polarized waves of Example 1 of this invention from the front. It is principal part sectional drawing which shows the cross-section of the vertically polarized antenna apparatus of Example 1 of this invention, and is sectional drawing which shows the cross-section along the A-A 'cutting line shown in FIG. It is a figure for demonstrating the structure of the 1st conductor of Example 1 of this invention, and a 2nd conductor. It is a graph which shows the directional characteristic in the horizontal surface of the antenna apparatus for vertical polarizations of a reference example. It is a graph which shows the horizontal plane directional characteristic of the antenna apparatus for vertically polarized waves of Example 1 of this invention. It is a graph which shows the radiation beam width in the horizontal surface of the vertically polarized antenna device of the reference example and the vertically polarized antenna device of Example 1 of the present invention. It is a graph which shows an example of the horizontal plane directional characteristic which used the antenna for vertical polarizations of a reference example for the base station antenna. It is a graph which shows an example of the horizontal plane directivity characteristic which used the antenna for vertically polarized waves of Example 1 of this invention for the base station antenna. It is a perspective view which shows schematic structure of the array antenna of Example 2 of this invention. It is a perspective view which shows schematic structure of the polarization sharing array antenna of Example 3 of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In all the drawings for explaining the embodiments, parts having the same functions are given the same reference numerals, and repeated explanation thereof is omitted.
[Example 1]
1 is a perspective view illustrating a schematic configuration of a vertically polarized antenna device according to a first embodiment of the present invention.
FIG. 2 is a front view of the vertically polarized antenna device according to the first embodiment of the present invention as viewed from the front. In FIG. 2, the reflection plate is not shown.
FIG. 3 is a cross-sectional view of the main part showing the cross-sectional structure of the antenna device according to the first embodiment of the present invention, and is a cross-sectional view showing the cross-sectional structure along the line AA ′ shown in FIG.
1 to 3, reference numeral 1 denotes a reflecting plate, 10 denotes a bottom reflecting plate constituting a reflecting surface, 11 denotes a side reflecting plate, 21 and 22 denote a pair of dipole antennas for vertical polarization, and 31 denotes a first conductive plate. The body, 32 is a second conductor, and 4 is a director.
As shown in FIG. 3, the side reflector 11 of the reflector 1 is bent to the back side of the bottom reflector 10, and the angle formed between the side reflector 11 and the bottom reflector 10 (θ in FIG. 3) is 90 °. It is as follows.
Here, the pair of half-wave dipole antennas (21, 22), the first conductor 31, the second conductor 32, and the director 4 are etched using, for example, a printed wiring board on a dielectric substrate. It is formed by a technique or the like.
As shown in FIG. 2, the first conductor 31 and the second conductor 32 are formed of a pair of half-wave dipole antennas (21, 22) along the extending direction of the pair of half-wave dipole antennas (21, 22). ) On both sides.
The first conductor 31 and the second conductor 32 limit the half-value width of the radiation beam in the horizontal plane of the vertically polarized radio wave radiated from the pair of half-wave dipole antennas (21, 22).

Here, as shown in FIG. 2, the length (L1) of the waveguide 4 and the lengths (L2) of the first conductor 31 and the second conductor 32 are values of the following equation (1). It is said.
[Equation 1]
0.25 × λo ≦ L1 ≦ 0.35 × λo
0.5 × λo ≦ L2 ≦ 0.65 × λo
(1)
Also, as shown in FIG. 3, the surface on which the pair of half-wave dipole antennas (21, 22) is arranged parallel to the bottom reflector 10 of the reflector 1 is the first surface (FA1 in FIG. 3), and the reflection The surface on which the first conductor 31 and the second conductor 32 are arranged parallel to the bottom reflector 10 of the plate 1 is the second surface (FA2 in FIG. 3), and the bottom reflector of the reflector 1 10, when the surface on which the director 4 is disposed is a third surface (FA3 in FIG. 3), the distance (L3) between the bottom surface reflecting plate 10 and the first surface of the reflecting plate 1, and The distance (L4) between the first surface and the third surface is a value of the following equation (2).
[Equation 2]
0.15 × λo ≦ L3 ≦ 0.30 × λo
0.20 × λo ≦ L4 ≦ 0.30 × λo
(2)
Furthermore, the distance (L5) between the first conductor 31 and the second conductor 32 and the width (L6) of the reflector 1 are values of the following equation (3).
[Equation 3]
0.45 × λo ≦ L5 ≦ 0.60 × λo
0.30 × λo ≦ L6 ≦ 0.50 × λo
(3)
Note that the second surface (FA2 in FIG. 3) is outside the first surface (FA1 in FIG. 3) when viewed from the bottom reflector 10 of the reflector 1 (in FIG. 3, the first surface (in FIG. 3)). (Above FA1) and inside the third surface (FA3 in FIG. 3) as viewed from the bottom reflector 10 of the reflector 1 (in FIG. 3, below the third surface (FA3 in FIG. 3)). At the position, the first conductor 31 and the second conductor 32 are set to positions where predetermined horizontal plane directivity can be obtained.

FIG. 4 is a diagram for explaining the configuration of the first conductor 31 and the second conductor 32 according to the first embodiment of the present invention.
As shown in FIG. 4, the first conductor 31 (or the second conductor 32) according to the first embodiment of the present invention includes a first slit 30a extending from both ends in the extending direction toward the central region and the first slit 30a. 2 slits 30b.
Here, the width (L8 in FIG. 4) of the first conductor 31 (or the second conductor 32) and the slit (30a, second conductor 32) of the first conductor 31 (or the second conductor 32). The length (L7 in FIG. 4) and the width (L9 in FIG. 4) of 30b) are values of the following equation (4).
[Equation 4]
0.20 × λo ≦ L7 ≦ 0.30 × λo
0.02 × λo ≦ L8 ≦ 0.03 × λo
0.01 × λo ≦ L9 ≦ 0.02 × λo
(4)

FIG. 5 is a graph showing the directivity characteristics in the horizontal plane of the vertical polarization antenna device of the reference example, and FIG. 6 is a graph showing the directivity characteristics in the horizontal plane of the vertical polarization antenna device of Embodiment 1 of the present invention. is there.
FIG. 7 is a graph showing the radiation beam width in the horizontal plane of the vertically polarized antenna device of the reference example and the vertically polarized antenna device of Example 1 of the present invention. In FIG. 7, A indicates the horizontal radiation beam width of the vertically polarized antenna device according to the first embodiment of the present invention, and B indicates the horizontal radiation beam width of the vertically polarized antenna device of the reference example.
As can be seen from FIG. 5 to FIG. 7, in the vertically polarized antenna device of this example, the half width value of the directional characteristics in the horizontal plane (the beam width at which the gain amount is −3 dB) is 80 °, which is the vertical of the reference example. Although it is the same as the polarization antenna device, the beam width at which the gain is −10 dB or less is about 140 °, which is narrower than the vertical polarization antenna device of the reference example.
This is because the first conductor 31 and the second conductor 32 of the present embodiment are half the radiation beam in the horizontal plane of the vertically polarized radio wave radiated from the pair of half-wave dipole antennas (21, 22). It is assumed that this is based on the result of improving the gain in the 0 ° direction shown in FIG. 6 of the vertically polarized radio wave by the director 4 while limiting the value width.
In the multi-frequency shared antenna described in Patent Document 1 described above, metal conductors are disposed on both sides of the half-wave dipole antenna to reduce the half-value width of the radiation beam in the horizontal plane at the highest frequency. In 1, the metal conductors arranged on both sides of the half-wave dipole antenna are arranged at positions inside the half-wave dipole antenna as seen from the reflecting surface of the reflector. Furthermore, Patent Document 1 does not describe disposing a director on a half-wave dipole antenna.
Further, in the vertically polarized antenna device of this embodiment, the gain on the back side of the reflector 1 is also greatly reduced. This is assumed to be due to the side reflector 11 of the reflector 1 of the present embodiment.

As described above, in general, when a base station of a mobile phone system has a three-sector configuration, antennas constituting each sector are arranged at the same base station with a 120 ° separation angle.
FIG. 9 shows the directivity characteristics in the horizontal plane when the three vertically polarized antennas of this embodiment are used as base station antennas and arranged at intervals of 120 °. 8 shows the directivity characteristics in the horizontal plane when the three vertically polarized antennas of the reference example are used as base station antennas and arranged at intervals of 120 °.
The vertical polarization antenna device of the reference example shown in FIGS. 5, 7, and 8 is the same as the first conductor 31 and the second polarization antenna device of the present embodiment shown in FIG. The antenna device is obtained by removing the conductor 32 and the director 4.
As can be seen from the graphs of FIGS. 8 and 9, by using the vertically polarized antenna device of the present embodiment shown in FIG. 1, compared to the vertically polarized antenna device of the reference example, three horizontal planes are used. A region where the internal directivity characteristics interfere with each other (gray portion in FIGS. 8 and 9) is reduced.

[Example 2]
FIG. 10 is a perspective view illustrating a schematic configuration of the array antenna according to the second embodiment of the present invention.
As shown in FIG. 10, the array antenna of the present embodiment is one in which the three vertically polarized antennas of the first embodiment described above are arranged on the reflector 1 with a predetermined interval. Even with such a configuration, it is possible to obtain the same effects as those of the first embodiment.
[Example 3]
FIG. 11 is a perspective view illustrating a schematic configuration of the polarization-sharing array antenna according to the third embodiment of the present invention.
As shown in FIG. 11, the dual-polarized array antenna of the present embodiment has three vertically polarized antennas and two horizontally polarized dipole antennas 5 of the first embodiment described above on the reflector 1. Are arranged at predetermined intervals. Even with such a configuration, it is possible to obtain the same effects as those of the first embodiment.
In each of the above-described embodiments, the case where a pair of half-wave dipole antennas 21 and 22 is used in order to set the half-width value of the directivity in the horizontal plane to 80 ° has been described. It is possible to vary the directivity in the horizontal plane.
As mentioned above, the invention made by the present inventor has been specifically described based on the above embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Of course.

DESCRIPTION OF SYMBOLS 1 Reflector 4 Waveguide 5 Horizontally polarized half-wave dipole antenna 10 Bottom reflector 11 Side reflectors 21, 22 A pair of vertically polarized dipole antennas 30a First slit 30b Second slit 31 First Conductor 32 Second conductor

Claims (5)

A reflector,
Comprising at least one half-wave dipole antenna disposed on the reflector;
An antenna device in which the polarization direction of radio waves radiated from the at least one half-wave dipole antenna is perpendicular to the ground,
A first conductor and a second conductor disposed on both sides of the at least one half-wave dipole antenna along an extending direction of the at least one half-wave dipole antenna;
The surface on which the at least one half-wave dipole antenna is disposed is parallel to the reflection surface of the reflection plate, the first surface, the reflection surface of the reflection plate, and the first conductor and the second surface. When the surface on which the conductor is disposed is the second surface, the second surface is located outside the first surface when viewed from the reflective surface of the reflector,
The antenna device, wherein each of the first conductor and the second conductor includes a first slit and a second slit extending from both ends in an extending direction toward a central region. Having a director disposed on the at least one half-wave dipole antenna;
When the third surface is parallel to the reflecting surface of the reflecting plate and the waveguide is disposed, the third surface is more than the second surface when viewed from the reflecting surface of the reflecting plate. The antenna device according to claim 1, wherein the antenna device is located outside.   2. The antenna device according to claim 1, wherein the at least one half-wave dipole antenna is a pair of half-wave dipole antennas arranged at a predetermined interval on the reflector. Having a waveguide disposed on the reflecting surface of the reflecting plate on a surface orthogonal to the reflecting surface of the reflecting plate and passing through the center of the pair of half-wave dipole antennas;
When the third surface is parallel to the reflecting surface of the reflecting plate and the waveguide is disposed, the third surface is more than the second surface when viewed from the reflecting surface of the reflecting plate. The antenna device according to claim 3, wherein the antenna device is located outside. A first antenna device in which the polarization direction of the radio wave is horizontal with respect to the ground;
An array antenna comprising a second antenna device in which the polarization direction of the radio wave is perpendicular to the ground,
The array antenna according to claim 1, wherein the second antenna device is the antenna device according to claim 1.

Images