JP2002026642A - Antenna system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna system that has a directivity whose half value width is about 100-120 deg. in a frequency band of a 3-sector configuration, and has a directivity whose half value width is about 60 deg. in a frequency band of a 6-sector configuration and whose directive direction is shifted to the right and left by about 30 deg. from the directive direction at a conventional frequency. SOLUTION: The antenna system is provided with a reflector 10 consisting of left right reflecting plates 11, 12 formed by folding a flat plate at its center line, a 1st dipole antenna 21 placed at a position formed by bisecting the center line of the reflector and used for a 1st frequency, and 2nd-5th dipole antennas 31-34 provided to the left right reflecting plates in a vertical symmetry with respect to the 1st dipole antenna and used at a 2nd frequency. A hybrid circuit is used for the dipole antennas 31-34 to feed power to the 2nd and 3rd dipole antennas and the 4th and 5th dipole antennas respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device used for a mobile communication system and the like, and more particularly to an antenna device used for a base station for mobile communication.

[0002]

2. Description of the Related Art Conventionally, an antenna having half-wavelength dipole antenna elements arranged in multiple stages in a vertical direction has been used as a base station antenna for mobile communication of an automobile, a cellular phone or the like. Also, when the operating frequency is in two separated frequency bands, a plurality of antennas are installed to cope with the problem. But,
In some cases, the number of mounted antennas is limited due to restrictions on the installation location and the like. In such a case, the above-described dipole antenna element is resonated in two frequency bands by two resonances. In this case, the number of antennas can be halved, but the directivities of the antennas in the two frequency bands are almost equal and only cover the same zone. Therefore, it was necessary to separately install an antenna to cover different wireless zones at two frequencies.

[0003]

With the recent increase in the number of mobile communications, in particular, the number of automobile and mobile phone subscribers, and the start of the provision of multimedia mobile communication services, the provision of mobile communication services at new frequencies is planned. And
For that purpose, it is necessary to install a base station antenna. However, locations that are suitable for the installation of base station antennas are often used for antennas of existing systems, etc., and methods of adding antennas to existing base stations rather than searching for new installation locations have been studied. I have. In addition, existing installation locations often have limitations such as the number of antennas, and it is effective to replace the antenna at a frequency for a new system with an existing antenna. For that purpose, it is necessary to share the antenna even when the system parameters differ from those of the existing system, and an antenna for that purpose is required.

[0004] In a conventional automobile / mobile phone system, a three-sector configuration is used using a directivity antenna having a half-value width of about 120 °. The service in the new frequency band is assumed to have a 6-sector configuration, with a half-width of about
Requires a 60 ° antenna. In this case, in the conventional antenna, one antenna cannot share an antenna having a different directivity and a different beam direction.

Therefore, the half-width has a directivity of about 100 to 120 ° in the frequency band of the three-sector configuration, and the half-width is about 60 ° in the frequency band of the six-sector configuration. For example, about 30
° had to be shifted antenna. As a solution to the above problem, the present applicant has proposed Japanese Patent Application No. 11-107510 “antenna device”, but in this case, there is only one beam corresponding to the new frequency band. for that reason,
For example, there is only one beam having a three-sector configuration. For this reason, for example, in the frequency direction of the 6-sector configuration with respect to the beam direction of the 3-sector configuration, for example, about 30
In order to make an antenna with a shifted beam, it is necessary to adopt an antenna configuration in which a two-element array antenna that is asymmetric with respect to the center lines arranged above and below the antenna device is horizontally inverted from the middle. In that case, there is a disadvantage that the antenna length becomes long.

An object of the present invention is to have directivity having a half width of 100 to 120 ° in a three-sector frequency band and to have a half width of about 60 ° in a six-sector frequency band.
An object of the present invention is to provide an antenna having directivity in which the directivity direction is shifted left and right by about 30 °, for example, from the directivity direction at the conventional frequency (the beam direction is shifted).

[0007]

According to the present invention, a first frequency-available first frequency which can be used at a certain distance in front of a reflector bent at an acute angle at the center of a flat plate and on the left and right center lines. Install a dipole antenna element. Further, the second and third dipole antenna elements usable at the second frequency are symmetrically arranged with respect to the center line of the reflector, and are arranged at a certain distance in front of the reflector. In addition, the second and third
The dipole antenna element feeds power through a hybrid circuit.

Here, the hybrid circuit means that a signal input to a terminal 81 as shown in FIG. 3 is output to a terminal 84 at an output phase α + 90 °, where α is an output phase of a terminal 83. The signal input to the terminal 82 is output to the terminal 83 at the output phase β + 90 °, where β is the output phase of the terminal 84. In other words, these circuits can supply power with a phase difference of 90 ° from each other. Further, in the present invention, the parasitic element which resonates at the first frequency or a frequency other than the first and second frequencies on the left and right center lines of the reflector and slightly ahead of the first dipole antenna element is provided in the antenna device. Install.

Further, in the present invention, in the above-mentioned antenna device, the second and third parasitic elements are provided slightly ahead of the second and third dipole antenna elements. Further, according to the present invention, in the above-mentioned antenna device, a pair of a second and a third dipole antenna element and a second and a third parasitic element are provided, and these are set to an upper part and a lower part with respect to the first dipole antenna element. And place it.

Further, according to the present invention, in the antenna device, a side reflector having both ends of the reflector bent forward is provided, or a set of parasitic elements having a certain length is provided. Further, according to the present invention, each of the above-described various antenna devices is installed in a plurality of stages in the vertical direction.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the drawings. (First Embodiment) FIGS. 1 and 2 show a first embodiment of the present invention. This embodiment shows an antenna device in a case where a 2 GHz band antenna which is being considered for use in the next mobile communication system is shared with a 900 MHz band antenna.

Here, the emission wavelength at 900 MHz is λ1, 2 GHz
Is λ2. A reflector in which left and right reflectors 11, 12 are obtained by bending a flat plate symmetrically with respect to the center line.
In front of the position that bisects the center line of the reflector 10 in front of 10
The dipole antenna element 21 for the 900 MHz band is installed vertically 1 / 4λ1 apart. The dipole antenna elements 31, 32, 33, and 34 for the 2-GHz band are planes perpendicular to a plane that bisects the reflector 10 to the left and right, and have a distance from a plane passing through the center line of the reflector 10 approximately. On the plane of 1/4 of λ1, dipole antenna elements 31 and 32 are centered on dipole antenna element 21.
The center of the dipole antenna elements 33 and 34 is located at about 1/3 of the lower about λ2, and the dipole antenna elements 31 and 33 are located forward of the dipole antenna element 21. , To the right about 1/4 of λ2,
The dipole antenna elements 32 and 34 are arranged at a position about 1/4 of λ2 on the left side toward the front of the dipole antenna element 21.

Dipole antenna element 31 for 2 GHz band
34 are connected to each other through the hybrid circuit 80, and elements 31 and 32, and 33 and 34 are at the same height. FIGS. 4 and 5 show the directivity of the antenna at each frequency when this embodiment is used. FIG. 4 shows that the directivity of the antenna at 900 MHz has a directivity with a half-width in the front direction (an angle formed by a point at which the radiation level is reduced by 3 dB from the maximum beam directivity) of about 120 °. Also,
FIG. 5 shows that at 2 GHz, the half-width has a directivity of about 60 ° in a direction of about 30 ° rightward from the front direction from the reflection plate 11.

However, in the case of FIG.
Shows the directivity when a signal is input to the input terminal 81 of FIG. When another signal is input to the terminal 82 at the same time, the directivity is symmetrical to the directivity of FIG. 5 (the half value width is about 60 ° in the direction of about 30 ° on the left side).
Directivity) is also obtained. (Second Embodiment) FIG. 6 shows a second embodiment of the present invention.

This embodiment is an embodiment in which a parasitic element 41 is mounted in front of the dipole antenna element 21 in the antenna apparatus of the first embodiment. FIGS. 7 to 9 show the directivity of the antenna at each frequency when the antenna device of the second embodiment is used. According to FIG.
The directivity of the antenna at Hz has a half-width of approximately 11 in the front direction.
It can be seen that the directivity is 0 °. According to FIG. 8, the parasitic element 41 installed in front of the dipole antenna 21 is used.
Has a directivity with a half-width of about 90 ° at 1.5 GHz. FIG. 9 shows that at 2.0 GHz, the half-width has a directivity of about 60 ° in a direction of about 30 ° rightward from the front direction from the reflection plate 11.

However, in the case of FIG.
Shows the directivity when a signal is input to the input terminal 81 of FIG. When another signal is input to the terminal 82 at the same time, a directivity symmetric to the directivity of FIG. 9 is obtained. (Third Embodiment) FIG. 10 shows a third embodiment of the present invention. In this embodiment, the parasitic elements 51 to 54 are provided in front of the dipole antenna elements 31 to 34 in the antenna device of the second embodiment.
FIG.

FIGS. 11 to 13 show the directivity of the antenna at each frequency when the antenna device of the third embodiment is used. According to FIG. 11, it can be seen that the directivity of the antenna at 885 MHz has a directivity with a half-width of about 100 ° in the front direction. According to FIG. 12, the half-width at 1501 MHz has a directivity of about 70 ° due to the effect of the parasitic element 41 provided in front of the dipole antenna 21. According to FIG. 13, it can be seen that at 2045 MHz, the half-width has a directivity of about 50 ° in a direction of about 30 ° leftward from the front from the reflection plate 11.

However, in the case of FIG.
Shows the directivity when a signal is input to the input terminal 82 of FIG. When another signal is input to the terminal 81 at the same time, directivity symmetrical to the directivity in FIG. 12 is obtained. (Fourth Embodiment) FIG. 14 shows a fourth embodiment of the present invention. This embodiment is different from the antenna device of the third embodiment in that
This is an embodiment in which side reflectors 13 and 14 are provided at both ends of reflectors 11 and 12 constituting the reflector 10 in parallel with a plane which bisects the reflector 10 to the left and right.

FIGS. 15 to 17 show the directivity of the antenna at each frequency when the fourth embodiment is used. According to FIG. 15, it can be seen that the directivity of the antenna at 885 MHz has a directivity with a half-value width of about 100 ° in the front direction. Also, FIG.
According to this, due to the effect of the parasitic element 41 provided in front of the dipole antenna 21, the half-width has a directivity of about 70 ° at 150 MHz. According to FIG. 17, it can be seen that at 2 GHz, the half-width has a directivity of about 60 ° in a direction of about 30 ° leftward from the front direction from the reflector 11.

However, in the case of FIG.
Shows the directivity when a signal is input to the input terminal 82 of FIG. When another signal is input to the terminal 81 at the same time, directivity symmetrical to the directivity in FIG. 12 is obtained. (Fifth Embodiment) FIG. 18 is a perspective view of a fifth embodiment of the present invention, and FIG. This embodiment is different from the antenna device of the third embodiment in that the reflector 10 intersects perpendicularly with a plane that bisects the reflector 10 to the left and right, and is located on a plane at a distance of about 1/6 of λ1 from the center line of the reflector 10. The center is located, the parasitic elements 61 and 62 whose centers in the vertical direction coincide with the dipole antenna elements 31 and 32, and the dipole antenna elements 33 and 34 in the vertical direction.
Parasitic elements 63 and 64 matched with are installed.

FIGS. 20 to 22 show the directivity of the antenna at each frequency when the antenna device of the fifth embodiment is used. According to FIG. 20, it can be seen that the directivity of the antenna at 885 MHz has a directivity with a half width of about 120 ° in the front direction. Further, according to FIG. 21, due to the effect of the parasitic element 41 installed in front of the dipole antenna 21, the half-width at 1501 MHz has a directivity of about 70 °. According to FIG. 22, it can be seen that at 2 GHz, the half-width has a directivity of about 60 ° in a direction of about 30 ° leftward from the front as viewed from the reflector 11.

However, in the case of FIG.
Shows the directivity when a signal is input to the input terminal 82 of FIG. When another signal is input to the terminal 81 at the same time, directivity symmetrical to the directivity in FIG. 12 is obtained. In the above embodiment, in the 800 MHz band, the half width in the front direction is about 100 to 120 °, 15
In the 00MHz band, the directivity was about 70 ° in the front direction, and in the 2.0GHz band, the directivity was about 60 ° in the direction of ± 30 ° from the front. However, the half width of each frequency band can be adjusted by changing the distance between each dipole antenna and the reflector, and can be adjusted to the required half width.

As described above, the present invention has been described based on the above embodiments. However, the present invention is not limited to the above embodiments, and can be carried out without departing from the gist thereof.

[0024]

As described above, by implementing the antenna device according to the present invention, in a certain frequency band, an antenna having a directivity having a half-value width of about 100 to 120 ° in the front direction is different from the above-mentioned frequency. An antenna having a directivity with a half-value width of about 60 ° and a maximum radiation direction shifted by, for example, 30 ° to the left and right in accordance with the input signals of the two input terminals of the hybrid circuit in frequency is one antenna apparatus. Became possible.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of an antenna device according to the present invention.

FIG. 2 is a three-view drawing showing a first embodiment of the antenna device of the present invention.

FIG. 3 illustrates a hybrid circuit.

FIG. 4 shows a 900 MHz antenna device according to the first embodiment of the present invention.
6 is a directional characteristic diagram based on a calculated value in FIG.

FIG. 5 shows a 2.0 GHz antenna device according to the first embodiment of the present invention.
6 is a directional characteristic diagram based on a calculated value in FIG.

FIG. 6 is a perspective view showing a second embodiment of the antenna device of the present invention.

FIG. 7 shows 800 MHz of the antenna device according to the second embodiment of the present invention.
6 is a directional characteristic diagram based on a calculated value in FIG.

FIG. 8 shows a 1.5 GHz antenna device according to a second embodiment of the present invention.
6 is a directional characteristic diagram based on a calculated value in FIG.

FIG. 9 shows a 2.0 GHz antenna device according to a second embodiment of the present invention.
6 is a directional characteristic diagram based on a calculated value in FIG.

FIG. 10 is a perspective view showing a third embodiment of the antenna device of the present invention.

FIG. 11 shows the 885 MHz antenna device according to the third embodiment of the present invention.
6 is a directional characteristic diagram based on a calculated value in FIG.

FIG. 12 illustrates a 1501 MHz antenna device according to a third embodiment of the present invention.
FIG. 4 is a directional characteristic diagram based on a calculated value at z.

FIG. 13 is a diagram illustrating an antenna device according to a third embodiment of the present invention.
FIG. 4 is a directional characteristic diagram based on a calculated value at z.

FIG. 14 is a perspective view showing a fourth embodiment of the antenna device of the present invention.

FIG. 15 shows 885 MHz of the antenna device according to the fourth embodiment of the present invention.
6 is a directional characteristic diagram based on measured values in FIG.

FIG. 16 shows a 150 MHz antenna device according to a fourth embodiment of the present invention.
6 is a directional characteristic diagram based on measured values in FIG.

FIG. 17 shows a 2.0 GHz antenna device according to a third embodiment of the present invention.
6 is a directional characteristic diagram based on measured values in FIG.

FIG. 18 is a perspective view showing a fifth embodiment of the antenna device of the present invention.

FIG. 19 is a three-view drawing showing a fifth embodiment of the antenna device of the present invention.

[FIG. 20] 885 MHz of the antenna device according to the fifth embodiment of the present invention.
6 is a directional characteristic diagram based on measured values in FIG.

FIG. 21 illustrates a 1501 MHz antenna device according to a fifth embodiment of the present invention.
FIG. 4 is a directional characteristic diagram based on measured values at z.

FIG. 22 shows a 2.0 GHz antenna device according to a fifth embodiment of the present invention.
6 is a directional characteristic diagram based on measured values in FIG.

[Explanation of symbols]

10 Reflector 11,12 Reflector constituting reflector 10, 13,14 Side reflector 21 Half-wave dipole antenna used at first frequency 31,32,33,34 Half-wave dipole antenna used at second frequency 41 Parasitic element shorter than about 1/2 of the wavelength of the first frequency 51,52,53,54 Parasitic element shorter than about 1/2 of the wavelength of the second frequency 61,62,63,64 Element 80 Hybrid circuit 81,82,83,84 Connection terminal in hybrid circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J020 AA03 BA07 BC09 CA04 DA03 DA04 DA09 5J021 AA05 AA06 AB03 BA01 CA06 DB03 FA32 FA34 GA04 GA08 HA05 HA10 JA03 JA07

Claims (8)

[Claims] 1. A reflector in which left and right reflectors obtained by bending a flat plate at a center line are arranged in a vertical direction, and a first reflector is provided at a position substantially bisecting the center line of the reflector.
And a second dipole antenna used at a second frequency provided on the left and right reflectors above a horizontal plane including the installation position of the first dipole antenna. A third dipole antenna; two fourth and fifth dipole antennas used at a second frequency provided on left and right reflectors below a horizontal plane including the installation position of the first dipole antenna; An antenna device, wherein power is supplied to each of the second and third dipole antennas and the fourth and fifth dipole antennas using a hybrid circuit. 2. The antenna device according to claim 1, wherein the first dipole antenna has an angle formed by a reflector of two.
On the surface to be equally divided, it is installed at a position about one quarter of the wavelength at the first frequency from the center of the reflector, and the second to fifth dipole antennas make the angle between the reflectors equal to 2 and so on. On a plane perpendicular to the separating plane and about one quarter of the wavelength at the first frequency from the center of the reflector, about four quarters of the left and right second frequencies toward the front of the reflector from the reflector. Is provided on a vertical straight line with a distance of about 1
In addition, the second and third dipole antennas are provided vertically above the center height of the first dipole antenna at two points each of which is about one third of the wavelength at the second frequency. The antennas are characterized in that the fourth and fifth dipole antennas are provided vertically below the center height of the first dipole antenna at two points of about one third of the wavelength at the second frequency. apparatus. 3. The antenna device according to claim 1, wherein the reflector is slightly separated from the first dipole antenna and parallel to the first dipole antenna on a plane bisecting an angle formed by the reflector. A first parasitic element for widening the first frequency with a certain installed length, or a second parasitic element having a length suitable for a frequency other than the first and second frequencies is provided. An antenna device, comprising: 4. The antenna device according to claim 1, wherein a length slightly shorter than said dipole antenna in parallel with each dipole antenna in front of said second to fifth dipole antennas. An antenna device comprising a third parasitic element having the following. 5. The antenna device according to claim 1, wherein both ends of the reflector are arranged so as to be parallel to a plane bisecting an angle formed by the reflector. An antenna device comprising a side reflector having a length. 6. The antenna device according to claim 1, wherein a vertical height at a center position of each of the second to fifth dipole antennas is the same in front of the reflector, An antenna device comprising: four fourth parasitic elements arranged on a plane perpendicular to a plane bisecting the reflector. 7. The antenna device according to claim 6, wherein a center is located slightly outside each of the four fourth parasitic elements, and a center is located at a position where the vertical height is equal to that of the first dipole antenna. An antenna device, comprising a fifth parasitic element having the following. 8. A multi-stage antenna device wherein the antenna device according to claim 1 is stacked in a plurality of stages in a vertical direction.