JP2005039415A - Antenna assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antenna assembly which provides a desired direction angle in a simple constitution. <P>SOLUTION: The antenna assembly 1 uses a wiring board antenna having feeders 3, 4 composed of microstrip lines, and antenna elements 5 composed of microstrip lines on a dielectric board 2. The size elements of the feeder 3, 4 and the antenna element 5 are deviated from those for obtaining a omnidirectivity, and take those for obtaining an elliptic directivity. A reflector plate 6 is installed with a specified inclination angle of e.g. 90° to the board 2 to obtain a pointing angle of 160°. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antenna device used for a mobile station base station antenna and the like, and more particularly to an antenna device that can obtain a desired directivity angle with a simple configuration.
[0002]
[Prior art]
In a base station antenna for mobile communication, a service area where a communication service can be provided from the base station antenna to the mobile station is greatly affected by the directivity of the base station antenna on the horizontal plane. When installing the base station antenna, it is desirable to install it in the best place where the service area to be provided can be provided without omission and without waste. That is, even if power is delivered to an area where a mobile station cannot exist, energy is wasted, and it is troublesome if power does not reach an area where a mobile station exists.
[0003]
In practice, the best place is on the road or other places where it is difficult to install the antenna, so it is often installed in a suboptimal place close to that place. For example, when an antenna having a figure 8 directivity on a horizontal plane is used and the longitudinal direction of the road 91 is to be mainly included in the service area as shown in FIG. 11, the best place is a point at the center of the road. 92. Since an antenna cannot be installed in the center of the road, it will be installed in a telephone pole or telephone box next to the road.
[0004]
However, when a base station antenna having an 8-shaped directivity 94 is installed at a point 93 on the road side as shown in FIG. 11, areas such as buildings 96 facing the road that do not need to be focused on as service areas are displayed. Because it is included, it is wasteful. Further, in FIG. 11, even if an antenna having omnidirectionality (circular directivity) on the horizontal plane is used instead of the antenna having figure-8 directivity, the longitudinal direction of the road 91 is included in the service area mainly. The request cannot be fulfilled.
[0005]
In FIG. 11, the directivity on the horizontal plane of an ideal antenna suitable for the installation environment is as indicated by a broken line 97. If the antenna has directivity as indicated by the broken line 97, the service area covered on the building side can be reduced.
[0006]
In recent years, the number of mobile stations existing in a narrow area has increased due to the widespread use of mobile station equipment, but a base station antenna using an omnidirectional antenna is installed as shown in FIG. If the service area is a circular service area around the installation site 101, there is a limit to the number of channels that can be provided by one base station, so that a sufficient number of channels cannot be secured for the number of mobile stations. Therefore, it is considered to secure a sufficient number of channels in each service area by installing a plurality of antennas having relatively narrow directivities in the same place and setting different directions as service areas. For example, as shown in FIG. 12B, if three antennas having a directivity angle of 120 ° are installed at the same location 101 and fan-shaped service areas facing in different directions are shared, a circular service area can be obtained. Three times as many channels can be secured.
[0007]
However, when the number of mobile stations further increases, it is necessary to install four or more antennas at the same installation location 101 as shown in FIG. In this case, since the service area 102 is formed at a narrow angle, the directivity of each antenna must be considerably narrowed.
[0008]
[Patent Document 1]
JP 11-31915 A [Patent Document 2]
Japanese Patent Laid-Open No. 8-125435
[Problems to be solved by the invention]
Patent Document 1 discloses a technique for obtaining omnidirectionality over a relatively wide band by using a substrate type antenna in which a dielectric substrate is provided with a feed line made of a microstrip line and an antenna element made of a microstrip line.
[0010]
Further, Patent Document 2 discloses that a circular service area is formed from a building by providing a reflector opposite to an omnidirectional antenna so that the omnidirectional characteristic shape is shifted in one direction. A technique for shifting away is disclosed.
[0011]
However, even if a reflector is provided opposite to an omnidirectional antenna as in Patent Document 2, only a directivity with a narrow directivity angle is obtained, and the service area that covers the building side as desired in FIG. 11 is reduced. The directivity on the horizontal plane of the antenna, that is, the wide directivity exceeding the directivity angle of 120 ° cannot be easily obtained. Further, the non-directional antenna as in Patent Document 1 cannot obtain the directivity 97 on the horizontal plane.
[0012]
When a plurality of antennas are installed at the same place for the purpose of narrowly dividing the service area, the directivity angle of the antennas needs to be a desired narrow angle corresponding to the number of divisions.
[0013]
In view of the above, an antenna that can obtain a desired directivity angle with a simple configuration from a wide directivity angle of 180 ° to a narrow directivity angle of about 30 ° is desired.
[0014]
Accordingly, an object of the present invention is to provide an antenna device that can solve the above-described problems and obtain a desired directivity angle with a simple configuration.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an antenna apparatus using a substrate type antenna in which a feed line made of a microstrip line and an antenna element made of a microstrip line are formed on a dielectric substrate. The dimension element is made to deviate from the dimension element capable of obtaining omnidirectionality to obtain an elliptical directivity, and the reflector is installed with a predetermined inclination angle with respect to the substrate.
[0016]
The inclination angle may be 90 °.
[0017]
The tilt angle may be 0 °.
[0018]
A plurality of the reflection plates may be provided, and each reflection plate may have the inclination angle with respect to the substrate.
[0019]
The plurality of reflection plates may be arranged with a predetermined crossing angle, and the plurality of substrates may be arranged with different inclination angles with respect to the reflection plates.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
[0021]
As shown in FIGS. 1 (a) and 1 (b), an antenna device 1 according to the present invention includes a feed line (open end) made of a microstrip line extending in the longitudinal direction of the substrate 2 on one surface of the substrate 2. 3), an antenna element 5 made of a microstrip line, a feed line 4 made of a microstrip line connecting the feed line 3 and the antenna element 5, and a microstrip line on the other surface of the substrate 2. A substrate type antenna 10 formed with a parasitic element 7 made of and a ground 8 made of a conductor is used. The ground 8 is located on the back side of the feed line 3, and the parasitic element 7 is located on the back side of the antenna element 5. A coaxial cable 9 for supplying power from an external transmission / reception device (not shown) to the substrate is disposed along the ground 8. In the substrate type antenna of the present embodiment, the parasitic element 7 is provided at a position corresponding to the antenna element 5 on the opposite surface of the surface on which the antenna element 5 is formed. It is also possible to arrange them so as to be parallel to the antenna element 5. The antenna element 5 has an electrical length of ½ wavelength in the longitudinal direction.
[0022]
The direction indicated by the z axis in the figure is the direction perpendicular to the horizontal plane. That is, the substrate 2 is placed with the longitudinal direction of the substrate 2 perpendicular to the horizontal plane. The dimension elements of the feed line 4 and the antenna element 5 that determine the directivity of the antenna device 1 are adjacent to the length of the feed line 4 (the distance between the open end line 3 and the antenna element 5) and the longitudinal direction of the substrate 2. The distance between the two feed lines 4 on the open end line 3 and the distance between the two antenna elements 5 adjacent to each other in the longitudinal direction of the substrate 2 are such that these dimensional elements are an integral multiple of the operating frequency λ or simple. By setting the integral multiple of such an integer, omnidirectionality (circular directivity) can be obtained on a horizontal plane. Details are described in Patent Document 1.
[0023]
The present invention intentionally deviates from the dimension element that provides the above omnidirectionality, and uses a dimension element that provides elliptical directivity on a horizontal plane using, for example, a value that cannot be simply obtained from the operating frequency λ. ing. For example, the distance between the two antenna elements 5 adjacent in the longitudinal direction of the substrate 2 is changed from the distance at which omnidirectionality is obtained. An example of the elliptical directivity thus obtained is shown in FIG. As shown in the figure, the gain at ± 90 ° (y-axis direction in FIG. 1) is smaller by about 3 dB or more than the gain at 0 ° and ± 180 ° (x-axis direction in FIG. 1).
[0024]
Returning to FIG. 1, the antenna device 1 according to the present invention is configured such that the reflecting plate 6 is installed with an inclination angle of 90 ° on the horizontal plane with respect to the substrate 2. That is, while the substrate 2 is along the x axis, the reflecting plate 6 is provided parallel to the y axis.
[0025]
FIG. 3 shows the directivity on the horizontal plane of the antenna device of FIG. As shown in the figure, directivity that is largely biased toward the semicircle on the side including 0 ° is obtained. Looking at the angle of −3 dB with respect to the maximum gain, it is ± 80 °. That is, a directivity angle of 160 ° is obtained.
[0026]
When the antenna apparatus of FIG. 1 having the characteristics of FIG. 3 is installed in the installation environment as shown in FIG. 11, the directivity on the horizontal plane becomes as shown by the broken line 97, the service area covering the building 96 side is reduced, and the length of the road 91 Direction can be focused on the service area. The characteristic indicated by the broken line 97 requires less power to reach an area where a mobile station cannot exist than the characteristic in which the non-directional characteristic shape is shifted in one direction as in Patent Document 2. That is, there is little waste.
[0027]
The antenna device 1 of FIG. 1 deliberately deviates from the dimensional elements of the conventional non-directional substrate type antenna to obtain the elliptical directivity of FIG. Since the reflector 6 is installed with an inclination angle of °, the characteristics shown in FIG. 3 that cannot be obtained by adding a reflector to a non-directional substrate type antenna as in Patent Document 2 can be realized. It was.
[0028]
In addition, the reflecting plate 6 may be in contact with the edge of the substrate 2 or may be installed appropriately separated from the edge of the substrate 2. The distance from the antenna element 5 to the reflecting plate 6 is preferably adjusted so that the directivity shown in FIG. The width of the reflecting plate 6 in the y-axis direction is preferably adjusted so that the directivity shown in FIG. The length of the reflecting plate 6 in the z-axis direction is substantially equal to the length of the substrate 2 in the z-axis direction. In FIG. 1, only four stages of the antenna elements 5 are shown in the z-axis direction, but actually, the antenna elements 5 may be provided in more or less stages than the four stages.
[0029]
Next, another embodiment will be described.
[0030]
As shown in FIG. 4A and FIG. 4B, the antenna device 1 is provided with the reflecting plate 6 with an inclination angle of 0 ° on the horizontal plane with respect to the substrate 2. That is, assuming that the substrate 2 is along the y-axis, the reflector 6 is provided in parallel to the y-axis. The substrate 2 is the same as shown in FIG. 1, and has a gain of ± 90 ° (in the x-axis direction in FIG. 4) with respect to gains of 0 ° and ± 180 ° (in the y-axis direction in FIG. 4) on the horizontal plane. Employs a dimensional element that provides an elliptical directivity of about 3 dB. The distance from the antenna element 5 to the reflecting plate 6 is preferably adjusted so that the directivity shown in FIG. The width of the reflecting plate 6 in the y-axis direction is preferably adjusted so that the directivity shown in FIG. The length of the reflecting plate 6 in the z-axis direction is substantially equal to the length of the substrate 2 in the z-axis direction.
[0031]
FIG. 5 shows the directivity on the horizontal plane of the antenna device 1 of FIG. As shown in the figure, directivity having a directivity angle of 120 ° is obtained. Looking at an angle of −3 dB with reference to a gain of 0 ° at which the gain is maximum, it is ± 60 °. That is, a directivity angle of 120 ° is obtained.
[0032]
As shown in FIG. 5, a plurality of the antenna devices of FIG. 4 having a small directivity angle on the horizontal plane are installed in the same place with different directions, so that FIG. 12 (b) or FIG. 12 (c). Thus, the service area can be divided into narrow areas.
[0033]
FIG. 6 shows the directivity on the horizontal plane of the antenna apparatus of FIG. 1, as in FIG. 3 differs from the elliptical directivity in the absence of the reflector 6. That is, the distance between the two antenna elements 5 adjacent to each other in the longitudinal direction of the substrate 2 is different from the distance at which the characteristics shown in FIG. 2 are obtained. As shown in FIG. 6, the directivity which is largely biased to the semicircle on the side including 0 ° is obtained. Looking at an angle of −3 dB with respect to the maximum gain, it is ± 90 °. That is, a directivity angle of 180 ° is obtained.
[0034]
Next, various other embodiments will be described.
[0035]
The antenna device 1 shown in FIGS. 7A and 7B is provided with a plurality of substrates 2. The respective substrates 2 are parallel to each other, and the angle formed with the reflecting plate 6 is the same. If the reflector 6 is installed at a place where a plurality of substrate type antennas 10 are installed so that elliptical directivity can be obtained on a horizontal plane as in these examples, FIG. 3, FIG. 5, FIG. 6 or other desired Directivity on a horizontal plane can be obtained.
[0036]
At this time, the antenna device 1 shown in FIGS. 7A and 7B is adjusted to a plurality of frequencies by one antenna device 1 by adjusting each substrate type antenna 10 to emit different radio waves. It becomes possible to respond.
[0037]
8A to 8F are obtained by providing a plurality of reflectors 6 for one substrate type antenna 10.
[0038]
Each reflector 6 is installed with various inclination angles on the horizontal plane with respect to the substrate 2. In FIG. 8A, one reflector 6 has an inclination angle of 90 ° with respect to the substrate 2, and the other two reflectors 6, 6 are parallel to the substrate 2 and the one reflector. 6 is installed in contact with both ends. In FIG. 8B, one reflector 6 has an inclination angle of 90 ° with respect to the substrate 2, and the other two reflectors 6, 6 have an inclination angle of ± about 30 ° with respect to the substrate 2. And is placed in contact with both ends of the single reflector 6. In FIG. 8C, the two reflecting plates 6 are installed at an inclination angle of ± about 45 ° with respect to the substrate 2. In FIG. 8D, one reflector 6 is installed in parallel with the substrate 2, and the other two reflectors 6, 6 are tilted at an angle of 90 ° with respect to the substrate 2. It is installed in contact with both ends. In FIG. 8 (e), one reflector 6 is installed in parallel with the substrate 2, and the other two reflectors 6 and 6 reflect the one reflector at an inclination angle of ± 60 ° with respect to the substrate 2. It is installed in contact with both ends of the plate 6. In FIG. 8 (f), the two reflecting plates 6 are installed at an inclination angle of ± about 45 ° with respect to the substrate 2.
[0039]
FIG. 9 shows the directivity on the horizontal plane of the antenna device 1 of FIG. Looking at an angle of −3 dB with reference to a gain of 0 ° at which the gain is maximum, it is ± 25 °. That is, a directivity angle of 50 ° is obtained. Thus, the directivity angle can be easily adjusted by changing the shape of the reflection plate 6.
[0040]
The antenna device 11 shown in FIG. 10 uses a plurality of reflection plates 6 shown in FIGS. 1 and 4 and the like, and these reflection plates 6 have a predetermined crossing angle to form a polygon on a horizontal plane. The same number of substrates 2 as the reflecting plates 6 are arranged with the same inclination angle with respect to each reflecting plate 6. Since the directivity on the horizontal plane of one set of the antenna device 1 by the pair of substrates 2 and the reflecting plate 6 has a narrow directivity angle, the antenna device 11 in which a plurality of such antenna devices 1 are installed at the same place is shown in FIG. ) Or as shown in FIG. 12C, it is suitable for the purpose of narrowly dividing the service area by the directivity 102 of each antenna device 1.
[0041]
【The invention's effect】
The present invention exhibits the following excellent effects.
[0042]
(1) A desired directivity angle can be obtained with a simple configuration.
[Brief description of the drawings]
FIG. 1 is an external view of an antenna device showing an embodiment of the present invention. (A) is a perspective view, (b) is sectional drawing seen from the z-axis direction.
2 is a characteristic diagram of horizontal plane directivity by a single substrate of the antenna device of FIG. 1;
FIG. 3 is a characteristic diagram of horizontal plane directivity of the antenna device of FIG. 1;
FIG. 4 is an external view of an antenna device showing another embodiment of the present invention. (A) is a perspective view, (b) is sectional drawing seen from the z-axis direction.
FIG. 5 is a characteristic diagram of horizontal plane directivity of the antenna device of FIG. 4;
6 is a characteristic diagram of horizontal plane directivity of a modified example of the antenna device of FIG. 1;
FIGS. 7A and 7B are external views of an antenna device according to another embodiment of the present invention.
FIGS. 8A to 8F are horizontal sectional views of an antenna device showing another embodiment of the present invention, respectively.
9 is a characteristic diagram of horizontal plane directivity of the antenna device of FIG.
FIGS. 10A to 10D are horizontal sectional views of an antenna device showing another embodiment of the present invention. FIGS.
FIG. 11 is a plan view of the vicinity of a road in which a base station antenna is installed on the side of the road.
FIG. 12 is a plan view showing a state in which a plurality of service areas are formed around one base station antenna installation location.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,11 Antenna apparatus 2 Substrate 3, 4 Feed line 5 Antenna element 6 Reflector 10 Substrate antenna

Claims (5)

In an antenna apparatus using a substrate-type antenna in which a feed line made of a microstrip line and an antenna element made of a microstrip line are formed on a dielectric substrate, the dimensions of the feed line and the antenna element are dimensions that can provide omnidirectionality. An antenna device, characterized in that an ellipsoidal directivity is obtained by deviating from the elements, and a reflecting plate is provided with a predetermined inclination angle with respect to the substrate. The antenna apparatus according to claim 1, wherein the inclination angle is 90 degrees. The antenna apparatus according to claim 1, wherein the inclination angle is 0 °. The antenna device according to any one of claims 1 to 3, wherein a plurality of the reflecting plates are provided and each reflecting plate has a different inclination angle with respect to the substrate. The plurality of reflectors are arranged with a predetermined crossing angle with each other, and the plurality of substrates are arranged with the inclination angles with respect to the respective reflectors. An antenna device according to any one of the above.

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