JP2001292023A - Antenna unit for mobile communication and antenna system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna system for mobile communication that can avoid a reception disturbance caused by intermodulation distortion that is a problem of a transmission reception common use antenna. SOLUTION: In order to solve a problem of the intermodulation distortion having been a problem of a conventional transmission reception common use antenna, the antenna elements in common use for transmission reception consist of combinations of antenna elements whose polarization differs from each other so as to prevent an intermodulation distortion noise intruded from a transmission antenna from being directly entered into a receiver without incurring increase in the size in comparison with the size of the conventional antenna. That is, the antenna system 1 consists of antenna units 2 of the same structure that are arranged vertically by a plurality of stages, and each antenna unit consists of the integration of a transmission vertical antenna element 21V and two diversity reception cross polarization antenna elements 21S1, 21S2 tilted horizontally by 45 deg. with respect to the transmission vertical antenna element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna apparatus for mobile communication in which a transmitting antenna and a receiving antenna are used in common, and a technique capable of preventing a reception failure caused by intermodulation distortion caused by transmission power. About.

[0002]

2. Description of the Related Art Recently used antennas include a system in which two vertically polarized antennas are horizontally arranged (horizontal diversity system) and a system in which one polarized antenna is used (polarization diversity system). .

[0003] In particular, as a currently used polarization antenna, a vertically polarized antenna element 1 shown in FIG.
One consisting of a combination of 00V and a horizontally polarized antenna element 100H and the other consisting of a combination of ± 45 ° slant polarized antenna elements 100S1 and 100S2 rotated by 45 degrees from horizontal or vertical polarization as shown in FIG. Types are mainstream.

[0004] With the recent rapid growth of subscribers to mobile communications such as mobile phones, the analog system has been replaced by
It is necessary to reduce the number of base station antennas due to the coexistence of the analog system and the digital system of time division or code division, and the restriction of the space for installing base station equipment due to the participation of multiple operators in one area. Is being pressed.
Therefore, it is common to share a transmitting antenna and a receiving antenna. In this case, in both the horizontal diversity system and the polarization diversity system, one system is used for both transmission and reception.

For example, in the polarization diversity antenna device 100 shown in FIG.
As a receiving element, and the vertical antenna element 10
0V is used as a transmitting / receiving antenna element. Also,
In the polarization diversity antenna device 200 shown in FIG.
One of the 45 ° right tilt antenna element 100S1 and the left 45 ° tilt antenna element 100S2 is a reception antenna element, and the other is a transmission / reception shared antenna element. In the figure, a 45 ° left tilt antenna element 100S2 is a transmission / reception shared antenna element.

On the other hand, the tower-top amplifier 300 used in the antenna device is configured as shown in FIG. 7, and has an input terminal 301 for transmission and reception and an input terminal 30 for reception only.
2 input terminals, and are connected to two antenna feeders.

[0007]

In the case where the transmitting antenna and the receiving antenna are shared as described above, failure of the antenna (deterioration of parts due to aging, loosening of solder, screws, etc. for connecting the antenna element and the like due to continuous vibration due to wind). ) Or when the arrangement of the transmission frequency and the reception frequency is a frequency that is susceptible to intermodulation distortion, that is, noise due to intermodulation distortion generated by the transmission power occurs in the reception band and interference with reception may occur. Likely to happen.

[0008] In view of the above, an object of the present invention is to provide:
It is an object of the present invention to provide an antenna unit and an antenna device for mobile communication capable of avoiding a reception failure caused by intermodulation distortion which is a problem in a transmission / reception shared antenna.

[0009]

SUMMARY OF THE INVENTION In order to solve the intermodulation distortion which is a problem in the conventional dual-purpose antenna for mobile communication, the antenna system for mobile communication according to the present invention uses an antenna element for transmission and reception which is different from an antenna element having a different polarization. By realizing the combination, the intermodulation distortion noise from the transmitting antenna is prevented from directly entering the receiver without increasing the size as compared with the conventional antenna.

That is, the antenna unit of the present invention comprises:
It is characterized in that a transmitting vertical antenna element and two diversity receiving cross-polarized antenna elements which are inclined left and right by 45 ° with respect to the transmitting vertical antenna element are integrated.

In addition to this configuration, a spare transmitting horizontal antenna element can be integrated.

On the other hand, the antenna device according to the present invention is characterized in that the antenna units having the above-described configuration are arranged in multiple stages in the vertical direction.

Here, in order to use the antenna in a plurality of sectors, the antenna unit having the above-described configuration is required
An antenna device having a configuration in which a plurality of antenna devices are arranged concentrically every time may be used.

Next, the present invention relates to a tower-top amplifier used in the antenna device having the above-described configuration, wherein one transmitting-only antenna output terminal, two receiving antenna input terminals, and the transmitting vertical antenna element are provided. Characterized in that it has a transmission band-pass filter for removing intermodulation distortion generated in the above, and a combiner for sharing the reception cable and the transmission cable.

[0015] The antenna feeder transmits and receives 2
In the case of drawing both of them individually, a tower-top amplifier having two receiving antenna input terminals may be used as shown in FIG.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a polarization diversity antenna device to which the present invention is applied will be described below with reference to the drawings.

FIG. 1 is an explanatory view showing a polarization diversity antenna apparatus to which the present invention is applied, and FIG. 2 is an explanatory view showing an antenna unit which is a basic component thereof. FIG. 3 is a schematic block diagram of a tower-top amplifier suitable for use in the antenna device of the present embodiment. In the antenna device 1 of the present example, the polarization diversity antenna conventionally used is a vertical and horizontal or ± 45 ° tilt type (also referred to as a cross type) polarization antenna. By adding a dedicated polarization antenna element for transmission, it is possible to prevent noise such as intermodulation distortion generated in the transmission antenna element from directly entering the receiver, and to combine this with the tower-top amplifier of this example. As a result, it is possible to cover two antenna feeders as in the related art.

More specifically, as can be seen from FIG. 1, the polarization diversity antenna device 1 of this embodiment has a configuration in which a plurality of sets of antenna units 2 having the same configuration are vertically arranged on a vertical plane. In the illustrated example, six sets of antenna units 2 (1) to 2 (6) are vertically arranged. The number of the antenna units 2 may be 5 or less, or 7 or more.

As shown in FIG. 2, each antenna unit 2 has a vertically polarized antenna element 21V as a transmission-only antenna element for separating transmission and reception.
And a slant (tilt) polarized wave antenna element 21 of right 45 ° and left 45 ° as a reception-only antenna element
S1 and 21S2 are provided.

In addition to this, the antenna unit 2 of this embodiment
Has a configuration in which the horizontal polarization antenna element 21H is arranged as a spare for additional transmission in consideration of a case where the transmission frequency increases in the future. Of course, the horizontal polarization antenna element 21H may be omitted.

As shown in FIG. 3, the tower-top amplifier 3 suitable for use in the polarization diversity antenna device 1 of this embodiment has two input terminals because the conventional tower-top amplifier uses the antenna for both transmission and reception. (See FIG. 7), one transmission output terminal 31 and two reception input terminals 32 and 33 are provided. The transmission cable 34 and the reception cable 35 are connected to the combiner 36 inside the tower-top amplifier 3 so that two antenna feeders are used as in the prior art (one for transmission and reception and one for reception only). The container 36 is connected to the antenna feeder terminal 51.

In order to prevent intermodulation distortion in the receiving band that may occur on the transmitting side during the combining by the combiner 36, the transmitting cable 34 is passed through a filter 37 that passes only the transmitting band. The output terminal for transmission 31 is connected.

The received wave input via the receiving input terminal 32 is input to the synthesizer 36 via the reception band filter 38 and the low noise amplifier (LNA) 39. Similarly, the reception wave input via the reception input terminal 33 also receives the reception bandpass filter 41 and the low noise amplifier (L
AN) 42 to an antenna feeder terminal 52.

In the case where the antenna hood is used individually for transmission and reception, that is, for a total of three antennas, FIG.
As shown in the above, a tower-top amplifier having two receiving antenna input terminals may be used.

The operation and effect of the antenna device 1 of this embodiment will be described. When a vertical antenna element is used exclusively for transmission and intermodulation distortion occurs in the transmission antenna element, the same antenna element is shared for reception in the related art, which directly affects the receiver. On the other hand, in the polarization diversity antenna device 1 of the present embodiment, the size of the antenna itself is changed by changing the polarization plane in the physically (structurally) identical antenna element, for example, in a patch antenna element. It is possible to reduce the influence of the receiver due to the intermodulation distortion generated in the transmitting antenna element without changing.

The antenna element itself can be, for example, a combination of a diball antenna other than the patch antenna.

Further, even when unnecessary wave noise due to intermodulation distortion occurs in the vertical antenna element, the receiving antenna element side has about 20-30 dB (about 1/100 to 1/1000) due to the difference in polarization plane and spatial loss. Since only low-level noise of ()) is added, it is possible to make the state almost unaffected.

Further, in the tower-top amplifier 3 of the present embodiment, since the bandpass filter 37 for passing only the transmission band is connected to the antenna output terminal 31 to which the transmission antenna is connected, unnecessary due to the intermodulation distortion generated in the reception band. Wave 70-9
About 0 dB can be removed.

Here, in order to use the antenna in a plurality of sectors, the antenna unit 2 having the above-described configuration is connected to the
An antenna device having a configuration in which a plurality of antenna devices are arranged concentrically at every 0 degree may be used.

[0030]

As described above, in the antenna unit of the present invention and the antenna device provided with the antenna unit, there is a possibility that the antenna may be generated in the transmitting antenna without increasing the number of physical antennas and the number of antenna feeders. Reception impairment due to a certain intermodulation distortion can be reduced to a level that causes almost no problem.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of a polarization diversity antenna device to which the present invention is applied.

FIG. 2 is an explanatory diagram showing an antenna unit which is a basic component of the antenna device of FIG. 1;

FIG. 3 is a schematic block diagram of a tower-top amplifier suitable for use in the antenna apparatus of FIG. 1;

FIG. 4 is a schematic block diagram showing an example of a tower antenna that can be used in the antenna device in FIG.

FIG. 5 is an explanatory diagram showing an example of a conventional vertical / horizontal polarization diversity antenna device.

FIG. 6 is an explanatory diagram showing an example of a conventional slant type polarization diversity antenna device.

FIG. 7 is a schematic configuration diagram of a conventional tower top amplifier.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna device 2, 2 (1) to 2 (6) Antenna unit 21V Transmission antenna element 21H Spare transmission antenna element 21S1 Receiving antenna element 21S2 Receiving antenna element 3 Tower amplifier 31 Output terminal 32, 33 Input terminal 51, 52 Antenna feeder terminal

Claims (6)

[Claims] 1. A vertical antenna element for transmission and two cross-polarized antenna elements for diversity reception inclined at 45 ° to the left and right with respect to the vertical antenna element for transmission are integrated. Antenna unit. 2. The antenna unit according to claim 1, further comprising a spare horizontal antenna element for transmission. 3. An antenna device, wherein the antenna units according to claim 1 or 2 are vertically arranged in multiple stages. 4. An antenna device comprising a plurality of the antenna units according to claim 1 arranged concentrically at 120 ° intervals. 5. The tower-top amplifier used in the antenna device according to claim 3 or 4, wherein one transmission-only antenna output terminal, two reception antenna input terminals, and the transmission vertical antenna element. 1. A tower-top amplifier comprising: a transmission band-pass filter for removing intermodulation distortion generated in the transmission cable; and a combiner for sharing a reception cable and a transmission cable. 6. A tower-top amplifier used for the antenna device according to claim 3 or 4, wherein the tower-top amplifier has two receiving antenna input terminals.