JP2747239B2 - Antenna device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device installed in a radio base station or the like of a mobile communication system such as an automobile telephone system, and more particularly to transmitting and receiving a transmission signal including a plurality of signal channels in a service area with a small insensitive band. The present invention relates to an antenna device.

[0002]

2. Description of the Related Art A conventional antenna device of this type will be described with reference to the drawings. FIG. 4 shows a conventional antenna device 10.
FIG. 5 is a diagram for explaining the installation conditions of A, FIG. 5 is a block diagram of the antenna device 10A, and FIG. 6 is a diagram showing signal radiation characteristics of the antenna device 10A.

Referring to FIG. 4, an antenna device 10A
Is installed on the roof of the building 30 of the wireless base station and connected to the transmitting device 20 in the building 30 by a coaxial cable or the like. The coordinate axis Y is perpendicular to the ground, and a plane formed by the coordinate axes Z and X (not shown) forms a horizontal plane with the ground. The antenna device 10A radiates a transmission signal from the transmission device 20 slightly downward from the horizontal plane so as to obtain a wide coverage area. FIG. 4 shows that the area between Z2a and Z4a in the Z-axis direction is formed as a cover area. Note that the transmission signal generally includes signals of a plurality of signal channels.

Referring to FIG. 5, an antenna device 10A
Are N antenna elements 1A, 1B,
, 1J,..., 1M, 1N (where J is an arbitrary integer from 1 to N, N is an integer of 2 or more).
Radiates into service area. The distributor 3 is a transmitting device 2
The transmission signal from 0 is distributed to each of the antenna elements 1J via a signal transmission line such as a coaxial cable. Each of the antenna elements 1J is a sector antenna using a dipole antenna with a reflector or the like. Also, a large number of antenna elements 1A to 1N are arranged in a vertical direction from the ground to narrow the radiation beam in the vertical direction. In this way, the antenna device 10A forms an array of transmission signals using the antenna elements 1A to 1N to form a radiation pattern having a large maximum gain and a narrow radiation beam width in the vertical direction.

Referring to FIG. 6A, which shows a cover area, the antenna device 20A forms a cover area FA in which the antenna gain Gt is set to a low gain limit. Also,
Referring to FIG. 6B which shows a vertical plane pattern of the antenna device 20A (a vertical plane pattern when the transmission signal emission direction of the antenna device 20A is the horizontal direction), the service of the radio base station in the antenna device 20A is referred to. The range in which the low gain limit Gt, which is the limit at which the
1a. Therefore, the cover area FA should be wider toward the antenna device 20A than the Z2a with respect to the Z axis. Therefore, a dead zone NA is generated near the antenna device 20A (a short distance zone).

[0006]

In the above-mentioned conventional antenna device, if the maximum gain is increased to obtain a high directivity in order to increase the coverage area, the beam width in the vertical direction becomes narrow, and the vicinity of this antenna device is reduced. It was impossible to avoid the formation of a dead zone.

[0007]

According to one aspect of the present invention, there is provided an antenna apparatus comprising: a plurality of antenna elements forming an array;
A distributor for distributing a transmission signal composed of a plurality of signal channels to each of the antenna elements, wherein a part of the transmission signal between a part of the antenna elements and the distributor A filter that passes only the signal channel in the frequency band is inserted.

In one of the antenna devices, a cover area of the transmission signal supplied to all of the antenna elements is set far from the antenna device, and the transmission signal in a frequency band not passing through the filter is set. It is possible to adopt a configuration in which the cover area is set near the antenna device.

[0009] Another one of the antenna devices may have a configuration in which the plurality of antenna elements are arranged in a vertical direction with respect to the ground.

[0010] An antenna device according to another aspect of the present invention includes:
In an antenna device including a plurality of antenna elements forming an array configuration and a distributor for distributing a transmission signal including a plurality of signal channels to each of the antenna elements, all of the plurality of antenna elements are all signals. The transmission signal including a channel is radiated to a first cover area set far from the antenna device, and a part of the plurality of antenna elements transmits the transmission signal excluding a signal channel of a first frequency band. The second set near the antenna device
Radiates into the cover area.

[0011]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a diagram for explaining installation conditions of an antenna device 10 according to an embodiment of the present invention, FIG. 2 is a block diagram of the antenna device 10, and FIG. 3 is a diagram showing signal radiation characteristics of the antenna device 10. is there.

Referring to FIG. 1, an antenna device 10 of the present embodiment is also installed on the roof of a building 30 of a radio base station, like a conventional antenna device 10A, and is provided with a transmitting device in the building 30 by a coaxial cable or the like. 20. The coordinate axes X, Y and Z are also set the same as in the conventional example. The antenna device 10 radiates a transmission signal including a signal channel of a first frequency band as a first cover area between Z1 and Z2 in the Z-axis direction, and transmits the transmission signal including all channels to a second coverage area. Z2 to Z in the Z-axis direction as the cover area
Emit between 4

Referring to FIGS. 2 and 3, similarly to the conventional example described with reference to FIGS. 5 and 6, the above-described antenna device 10 has n antenna elements 1a, 1b,. , 1j, ..., 1m, 1n (where j is 1
A transmission signal is radiated from the antenna block 1 including an arbitrary integer from to n, where n is an integer of 2 or more) into the service area of the transmitting device 20 (radio base station). The distributor 3 distributes a transmission signal from the transmission device 20 to each of the antenna elements 1j via a signal transmission line such as a coaxial cable. These many antenna elements 1a to 1n are arranged in a vertical direction from the ground so as to narrow the vertical radiation beam width.

Here, the antenna device 10 of the present embodiment
A filter (2a in this embodiment) that allows only a part of the transmission signal of the transmission signal, that is, the transmission signal of the signal channel of the first frequency band, to pass between some of the antenna elements 1a and 1b and the distributor 3. And 2b) are inserted. Since the transmission signals of the signal channel of the first frequency band are array-combined by all the antenna elements 1a to 1n, they are radiated into the service area with a radiation pattern PA having a large maximum gain and a narrow radiation beam width in the vertical direction. Is done. On the other hand, among the antenna elements 1a to 1n, the antenna elements other than the antenna elements 1a and 1b combine the transmission signals excluding the signal channel of the first frequency band in an array. When the antenna block 1 synthesizes an array of transmission signals except for the antenna elements 1a and 1b,
Although the maximum gain is smaller than the above, a radiation pattern PB having a wider radiation beam width in the vertical direction can be obtained. In this case, the vertical plane radiation angle at which the low gain limit Gt is obtained is the angle 2θ1 in the radiation pattern PA at which a larger maximum gain is obtained,
In the radiation pattern PB having a small maximum gain, a larger angle 2θ2 is obtained (see FIG. 3B).

Therefore, the coverage area (first coverage area Fa) of the transmission signal in the first frequency band is set far from the antenna device 10 by taking advantage of the feature that the maximum gain is large. Excluding transmission signal coverage area (2nd
The coverage area Fs) is set near the antenna device 10 by taking advantage of the feature of a large vertical plane radiation angle, so that the service area of the transmission device 10 (the radio base station or the transmission device 20) can be widened, and the antenna device The dead zone near 10 can be eliminated (FIGS. 1 and 3A).
reference). The cover area F of such an antenna device 10
The center position (maximum gain position) of a and Fb is determined by the phase adjustment of the transmission signal supplied to the antenna elements 1a to 1n,
This is achieved by disposing the antenna element 1j connected to the filter in the antenna block 1. Since the cover area Fa far from the antenna device 10 has a larger cover area, the above-described phase adjustment and the like are performed in the cover area F.
It is better to give priority to achieving a.

As described above, the antenna device 1 of the present embodiment
0 forms a different vertical beam width for each frequency band of the transmission signal (and the reception signal), and makes the coverage areas of the different beam widths different from each other, so that the insensitive band NA as occurs in the conventional antenna apparatus 10A. Can be narrowed.

Although the antenna device 20 of the present embodiment has been described with respect to an example in which two vertical beam widths are formed, the signal passing band of the filters 2a to 2n is further divided into a plurality of antenna elements 2a. Or 2n
It is clear that if the signal pass band supplied to the antenna is further divided, a large number of vertical beam widths different from each other can be formed, and an antenna device capable of forming various cover areas can be obtained.

[0019]

As described above, according to the present invention, a signal of a part of frequency band of a transmission signal is provided between a part of the antenna elements in the array and the distributor. Since a filter for passing only a channel is inserted, a different vertical beam width is formed for each frequency band of a transmission signal (and a reception signal), and the coverage areas of the different beam widths are made different from each other, so that the conventional antenna device is used. As described above, there is an effect that the range of the dead zone can be narrowed.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining installation conditions of an antenna device 10 according to an embodiment of the present invention.

FIG. 2 is a block diagram of the antenna device 10.

FIG. 3 is a diagram showing signal radiation characteristics of the antenna device 10;

FIG. 4 is a diagram for explaining installation conditions of a conventional antenna device 10A.

FIG. 5 is a block diagram of an antenna device 10A.

FIG. 6 is a diagram illustrating signal radiation characteristics of the antenna device 10A.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna block 1a, 1b, 1m, 1n Antenna element 2a, 2b Filter 3 Divider 10 Antenna device 20 Transmitting device 30 Building

Claims (5)

(57) [Claims] 1. An antenna device comprising: a plurality of antenna elements forming an array configuration; and a distributor for distributing a transmission signal including a plurality of signal channels to each of the antenna elements. An antenna device, wherein a filter that passes only the signal channel in a part of the frequency band of the transmission signal is inserted between the antenna and the distributor. 2. The antenna according to claim 1, wherein a cover area of the transmission signal supplied to all of the antenna elements is set far from the antenna device, and a cover area of the transmission signal in a frequency band not passing through the filter is defined as the antenna device. 2. The antenna device according to claim 1, wherein the antenna device is set in the vicinity of. 3. The apparatus according to claim 1, wherein the plurality of antenna elements are arranged vertically with respect to the ground.
The antenna device as described in the above. 4. The antenna device according to claim 1, wherein the filters have different frequency bands. 5. An antenna device comprising: a plurality of antenna elements forming an array configuration; and a distributor for distributing a transmission signal including a plurality of signal channels to each of the antenna elements, wherein all of the plurality of antenna elements are provided. Radiating the transmission signal of the signal channel of the first frequency band to a first cover area set far from the antenna device, wherein a part of the plurality of antenna elements is An antenna device, wherein the transmission signal excluding a signal channel is radiated to a second cover area set far from the antenna device.