JPH11168318A - Multi-frequency shared sector antenna device - Google Patents

Abstract

(57) [Problem] To provide an antenna device used for a high-speed wireless LAN terminal or the like, which aims at realizing a multi-frequency shared multi-sector antenna which can be made small and thin. SOLUTION: A ground plate whose surface is a conductor, a cylindrical reflector plate whose surface is a metal on the surface of the ground plate, and a plurality of conductor surfaces whose surfaces extend radially outward from the cylindrical reflector plate. And two or more adjacent partition plates or an extension thereof and a region (hereinafter referred to as a sector) sandwiched between a portion of the reflector and one or more of the partition plates.
In a sector antenna device configured by an antenna device installed one after another and an antenna changeover switch that switches the antenna device for each sector, when a group including a plurality of antenna devices operating at the same frequency is defined as an antenna device group, A plurality of antenna device groups each having a different operating frequency are installed on the same ground plane, and each antenna device has a configuration in which the partition plate is shared with another adjacent antenna device.

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 high-speed wireless LAN terminal or the like, and more particularly to a multi-frequency antenna in which one antenna device is used at a plurality of different frequencies. And an antenna device that can simultaneously satisfy antenna characteristics required for each system.

[0002]

2. Description of the Related Art In recent years, high-speed wireless LAN systems have attracted attention, and the frequencies studied as shown in Table 1 are:
19 GHz, 2.4 GHz, 5 GHz, and 60 GHz.

[0003]

[Table 1]

It is effective to use a narrow beam with a large multipath suppression effect to increase the transmission speed (Literature: Kazuhiro Uehara, Tomohiro Seki, Kenichi Kagoshima: "Indoor propagation characteristics for arbitrary directional antennas by geometric optics method" Analysis ", IEICE BII, vol. J78-BII, No. 9, pp. 593.
-601, 1995. reference). Therefore, a multi-sector antenna capable of forming a narrow beam in all directions is effective.

[0005] If a single antenna device can realize a narrow beam multi-sector antenna at arbitrary plural frequencies such as 5 GHz and 19 GHz or 19 GHz and 60 GHz, it is possible to improve the convenience of those who use terminals and to improve the base station equipment. This can contribute to a reduction in installation work.

However, it is difficult to reduce the size of the conventional narrow beam multi-sector antenna even if it is designed with one frequency, and there is no antenna device that is small and realizes multi-frequency use.

FIG. 10 is a diagram showing an example of a conventional dual-frequency antenna device (Japanese Patent Application No. 4-347588). In the figure, numeral reference numeral 1 denotes device operating at a first frequency f _1, the two elements that operate at a second frequency f _2, 3 is a reflector, L is a reflector length, alpha is a corner angle.

In the antenna of FIG. 10, the beam width is determined by the corner length L, and an equal beam width can be obtained at two frequencies by properly adjusting the corner angle α (Reference: Suzuki).
Tamami, Kenichi Kagoshima: “Corner reflector antenna with dual beamwidths for two arbitrary frequency bands”, IEICE, B-II, V
ol. J75-BII, No. 12, pp. 950-95
6, December 1992. reference).

However, an antenna having such a structure is
The length L and the corner angle α are both f ₁F_Two
It also affects the operation in
And it is difficult to make a narrow beam. In addition, such corners
A 12-sector antenna consists of a reflector type antenna
The antenna opening area is the corner angle and the corner length.
Because it is almost determined by the arc obtained and the height of the reflector,
It is difficult to model (Literature: Tadashi Shirato, Tetsuro Hanazawa, Okada
 Takashi, Maruyama Tamami: "Development of High-Speed Wireless LAN Device", N
TT R & D, Vol. 45, no. 8, pp. 95-
104, Aug. , 1996. reference).

In another example of the conventional dual frequency antenna, a multi-sector antenna operating at a first frequency is configured as a planar patch antenna, and its ground plane is combined with a parasitic element of an antenna element operating at a second frequency. (Japanese Patent Application No. 8-215943). However, this antenna operating at the second frequency is omni-directional and cannot obtain a sector beam.

Next, an example of a conventional thin multi-sector antenna is shown in FIG. In the figure, numeral 21 denotes a feed element, 22 denotes a director, and 23 denotes a feed element 21 and a director 22.
Monopole Yagi-Uda antenna composed of 2,
4 is a base plate, 25 is a partition plate, 26 is a cylindrical reflector,
2s is the diameter of the cylindrical reflector, 2r is the diameter of the main plate, h
r is the height of the partition plate.

In the present antenna, by using a director, a 30 ° beam can be obtained with a volume of 1/3 as compared with the case where a three-dimensional corner reflector is used (Reference:
Tamami Maruyama, Kazuhiro Uehara, Kenichi Kagoshima: "Analysis and Design of Small Multi-Sector Antenna for Wireless LAN Using Monopole Yagi-Uda Array Antenna", IEICE B-II, Vo
l. J-80-B-II, No. 5, pp. 424-43
March and May. , 1997. reference).

However, since the present antenna has a structure in which the director is disposed in front of the feed element, it is difficult to use the element operating at the second frequency in two frequencies in front of the feed element as shown in FIG. It was difficult.

FIG. 12 shows a multi-sector monopole Yagi-Uda antenna when the number of sectors is six. In this antenna, the beam width on the horizontal plane is determined by the array length la, and the beam width on the vertical plane is determined by the ground plane length gl. Reference numeral 25 denotes a partition plate, which is installed to suppress unnecessary reflection from a power supply element of an adjacent array, which occurs when a switch that is not supplied with power is used.

When the diameter 2s of the central cylinder 26 is widened for installation of a sector changeover switch or the like, the partition plate becomes far from the feed element as shown in FIG. If α is reduced in order to control the directivity by using the partition plates, the number of necessary partition plates is doubled as shown in (b), and a useless space is generated between the partition plates.

In order to avoid this, the diameter of the entire antenna can be reduced by reducing 2 s in order to bring the partition plate closer to the feed element, but the cylinder 26 cannot be used as a switch storage space or return loss increases. Cause problems.

[0017]

As described above, the conventional dual frequency antenna is difficult to be applied to an antenna using a director and cannot be used as a sector antenna. Further, there is a problem that the conventional thin multi-sector antenna cannot be used at a plurality of frequencies. The present invention has been made to solve these problems, and it is an object of the present invention to realize a thin multi-frequency shared multi-sector antenna without changing the height or size of a conventional thin multi-sector antenna. .

[0018]

According to the present invention, the above-mentioned object is solved by the means described in the claims.

That is, according to the first aspect of the present invention, there is provided a ground plate having a surface as a conductor, a metal-made cylindrical reflecting plate on a surface of the ground plate, and a radially outward direction from the cylindrical reflecting plate. A plurality of partitioning plates whose surfaces extend are conductors are erected, and all or one of two adjacent partitioning plates or an extension of the partitioning plate and a region (sector) sandwiched between a part of the reflecting plate is provided. Antenna devices installed one by one in each section,

In a sector antenna device including an antenna changeover switch for switching the antenna device for each sector, when a group of a plurality of antenna devices operating at the same frequency is defined as an antenna device group, a plurality of antenna devices having different operating frequencies are used. Are installed on the same ground plane, and each antenna apparatus is a multi-frequency sector antenna apparatus having a configuration in which the partition plate is shared with another adjacent antenna apparatus.

According to a second aspect of the present invention, in the multi-frequency shared sector antenna apparatus of the first aspect, the antenna device of one of the plurality of antenna device groups is constituted by one feed element. It was done.

According to a third aspect of the present invention, in the multi-frequency shared sector antenna apparatus according to the first aspect, the antenna device of one of the plurality of antenna device groups includes one feed element and a plurality of waveguide elements. It is configured so as to be composed of a monopole element row composed of a container.

According to a fourth aspect of the present invention, in the multi-frequency sector antenna device according to any one of the first to third aspects, the antenna device of at least one of the plurality of antenna device groups is selected from the group consisting of: This is configured as a corner reflector antenna including a feed element and two partition plates adjacent to the feed element.

According to a fifth aspect of the present invention, there is provided the multi-frequency shared sector antenna device according to any one of the first to third aspects, wherein an antenna device of at least one of the plurality of antenna device groups is provided. , A horn antenna including a feed element, two partition plates adjacent to the feed element, and a lid of a metal plate covering upper portions of the two partition plates.

According to a sixth aspect of the present invention, in the multi-frequency shared sector antenna device according to the fourth or fifth aspect,
At least one antenna device constituting the antenna device group is loaded with a dielectric.

According to a seventh aspect of the present invention, in the multi-frequency shared sector antenna device according to any one of the fourth to sixth aspects, a metal fin is loaded on at least one of the antenna devices constituting the antenna device group. It is composed.

According to an eighth aspect of the present invention, in the multi-frequency shared sector antenna device according to any one of the fourth to seventh aspects, a director is loaded on at least one of the antenna devices constituting the antenna device group. It is configured.

The multi-frequency shared sector antenna device of the present invention has a structure as described above, for example, in which a partition plate attached to a multi-sector monopole Yagi-Uda antenna operating at the first frequency is moved at the second frequency. By using a reflector of an operating corner reflector, a dual-frequency antenna can be realized.

Also, for example, a dual-frequency antenna can be realized by using a partition plate attached to the thin sector antenna operating at the first frequency as a part of the horn antenna operating at the second frequency.

The partition plate of the multi-sector monopole Yagi-Uda antenna is used to control unnecessary radiation from the adjacent array. However, in order not to impair the original characteristics of the Yagi-Uda antenna. It is desirable that the length is set to a length covering the feed element, that is, about 0.5 wavelength.

On the other hand, the longer the corner length of the corner reflector, the sharper the directivity. In the present invention, by using the antenna operating at the high frequency as the second sector antenna, it becomes possible to make the partition plate which is electrically short enough at the low frequency to be electrically long enough at the high frequency.

According to the multi-frequency sector antenna apparatus of the present invention, for example, even when the length of the partition plate is limited to the first frequency, the second multi-sector antenna can be provided with a dielectric, a metal fin, By using the director, desired characteristics (beam width) for the second multi-sector antenna
Can be set.

At the first frequency, the monopole element operates as a director, and is ignored at the second frequency. Because, when the second frequency is low (long wavelength), the monopole element is negligibly small in wavelength, and when the second frequency is high (short wavelength), the distance between the monopole elements is small. It does not work because it is electrically far away. Therefore, by using this monopole element as a director, a reflector having the same size can be used at two frequencies, three frequencies, and any frequency ratio.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below as examples. FIG. 1 is a view showing a first embodiment of the present invention, showing an example of a frequency shared antenna device, wherein (a) is a perspective view and (b) is a top view.

This antenna device has a first low frequency f
6 sector antenna operating at ₁ and second high frequency f ₂
This is an antenna device in which one antenna device shares the 6-sector antenna operated by the above.

In FIG. 1, numeral 1 is an element operating at the first frequency f _{1. In} the case of this embodiment, this is a monopole Yagi-Uda antenna indicated by numeral 23. With figures reference numeral 25 is a partition plate of the monopole Yagi-Uda antenna, a reflector 3 of the corner reflector antenna as the second sector antenna operating at the frequency f _2.

Numeral 2 denotes a radiating element of the second sector antenna, 24 denotes a ground plane, and 26 denotes a cylindrical reflector. Alphabet codes 2r denote the diameter of the ground plane 24, 2s denotes the diameter of the cylindrical reflector 26, gl indicates the length of the ground plate (the distance from the cylindrical reflector 26 to the end of the ground plate), la indicates the array length, lr indicates the length of the partition plate, and hr indicates the height of the partition plate. The same applies to other drawings described below.

The corner reflector antenna includes a feed element 2 and two partition plates 3 adjacent to the feed element 2.
And an antenna composed of here,
In the monopole Yagi-Uda antenna, the beam width on the horizontal plane is adjusted by the array length la, and the beam width on the vertical plane is adjusted by the ground plane length gl.

In the corner reflector antenna, if the length of the partition plate 3 is at least one wavelength of the radio frequency to be used, the beam width can be adjusted by the corner angle β. But,
If the length of the partition plate 3 is less than one wavelength, the length is adjusted by the length and height of the partition plate 3 in addition to the corner angle. In the corner reflector antenna, the value of the length cl of the arc contributing to the aperture area is changed according to the frequency used.

For example, if the first low frequency f ₁ is 5 GHz
z, the second high frequency f ₂ is 19.6 GHz,
Length lr of the partition plate when the 0.5 wavelength at f _1, becomes 1.95 wavelength f _2. Here, although an example when 0.5 wavelength length lr of the partition plate at the frequency f _1, it is necessary to determine the length, etc. of the partition plate in consideration of the frequency used by each antenna.

For example, if the first low frequency f ₁ is 5 GHz
z, the second high frequency f ₂ is 19.5 GHz,
Length lr of the partition plate when the 0.5 wavelength at f _1, becomes 1.95 wavelength f _2.

FIG. 2 shows a dual-frequency antenna device according to a second embodiment of the antenna device comprising a plurality of antenna groups having different operating frequencies. FIG. 2 shows that the same monopole Yagi-Uda antenna as in FIG. 1 is used for each element of the sector antenna operating at the first frequency, and the diameter of the cylindrical reflector is 2.
This is an example in which s is different in size from the case of FIG. By doing so, the value of the length cl of the arc that contributes to the aperture area of the second sector antenna can be changed according to the frequency.

That is, as shown in FIG. 2, the corner angle α of the antenna forming the monopole Yagi-Uda antenna
By changing the diameter 2s of the cylindrical reflector while keeping the constant, it is possible to change the corner angle of the antenna constituting the corner reflector antenna from the angle β to the angle β ′. In FIG. 2, parts corresponding to the respective parts in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In the drawings described below, the same reference numerals are given to the portions corresponding to the respective portions already described, and the description thereof will be omitted.

Next, a dual-frequency antenna device according to a third embodiment of the antenna device comprising a plurality of antenna groups having different operating frequencies is shown in FIGS. FIG. 3 (a),
(B) is an example when the horn antenna 27 is used as the antenna operating at the second frequency. FIG. 3A shows a case where the antennas operating at two frequencies are each made up of six sectors, and FIG. 3B shows a case where the antennas are made up of eight sectors. The sides of the horn antenna are shared with the sides of the monopole Yagi and Uda antennas.

Here, the horn antenna includes a feed element, two partition plates adjacent to the feed element,
An antenna composed of a metal cover that covers the upper part of a partition plate. The beam width of the horn antenna can be adjusted according to the opening area of the horn antenna. The radiation pattern can be changed by changing the length of the opening in the vertical direction and the length in the horizontal direction.
Therefore, the design value of the horn antenna is determined in consideration of these points.

FIG. 4 shows a dual-frequency antenna device according to a fourth embodiment of the antenna device comprising a plurality of antenna groups having different operating frequencies. FIG. 4 shows an antenna having the same structure as that of FIGS. 3A and 3B, in which a dielectric 4 is loaded on a horn antenna 27 operating at a second frequency.

According to the present invention, even when the size of the partition plate and the diameter 2s of the cylinder are limited, the thickness of the dielectric 4 and the value of the relative permittivity are adjusted to obtain a desired beam at a desired frequency. It becomes possible to obtain the width. Also in the corner reflector antenna, a desired beam width can be obtained at a desired frequency by similarly loading a dielectric and adjusting the thickness and the relative permittivity.

FIG. 5 shows a dual-frequency antenna device according to a fifth embodiment of the antenna device comprising a plurality of antenna groups having different operating frequencies. FIG. 5 is an example in which a sector antenna operating at the second frequency is used as a corner reflector and metal fins indicated by reference numeral 5 are loaded to perform control for obtaining a desired beam width at a desired frequency.

Here, the beam width is adjusted by preparing a metal fin having an optimum length in the circumferential direction of the antenna device.
The adjustment is performed by adjusting the number of sheets and the length in the direction of the feeding element (the width of the metal fin). Note that the beam width of the horn antenna can be adjusted in the same manner using metal fins.

Next, a dual-frequency antenna device according to a sixth embodiment of the antenna device comprising a plurality of antenna groups having different operating frequencies is shown in FIG. FIG. 6 shows that the sector antenna operating at the second frequency is a corner reflector antenna, and the second sector antenna is also loaded with the director 6, thereby performing control to obtain a desired beam width at a desired frequency. It is an example.

Here, the adjustment of the beam width is performed as follows. The height of the director 6 and the feed element 2 is set to about １ ／ wavelength of the desired frequency. As the diameter of the element becomes larger, the height is made slightly smaller than <1/4 wavelength, and is adjusted so as to resonate at a desired frequency. The director 6 is connected to the feed element 2 so that a radio wave propagates from the feed element 2 to the director 6.
Shorter than. Thus, the length of the element contributes to the operating frequency.

On the other hand, in terms of the beam width, the directivity of the horizontal plane and the conical surface becomes sharper by installing the waveguide.
The extent varies with the number of directors. In other words, the more the number, the sharper. Also, in the case of a horn antenna, the length of the feed element should be set to 1/4 wavelength of the operating frequency, and the beam width adjusted to the frequency can be adjusted by installing a parasitic element or a director. Is possible.

Next, FIG. 7 shows a dual-frequency antenna device according to a seventh embodiment of the antenna device comprising a plurality of antenna groups having different operating frequencies. FIG. 7 shows an example in which six sector antennas operate at the first frequency and three sector antennas operate at the second frequency. At this time, the horizontal width at half maximum of the first sector antenna is 60 ° (=
It is preferable that the horizontal width at half maximum of the second sector antenna is 120 ° (= 360 ° / 3 sectors), and that each frequency can cover the circumferential direction (360 °).

Next, FIG. 8 shows a three-frequency shared antenna device according to an eighth embodiment of the antenna device comprising a plurality of antenna groups having different operating frequencies. FIG. 8 shows a six-sector antenna operating at the first frequency, a three-sector antenna operating at the second frequency, and a three-sector antenna operating at the third frequency indicated by numeral 7 in one antenna device. This is an example of realization. According to the present invention, as shown in FIG. 8, the number of shared frequencies is not limited to two and may be any number.

In FIG. 8, the sector antenna of the second frequency and the sector antenna of the third frequency are both half-width 120 ° using reflectors having the same physical size and different electrical sizes. In order to obtain, at one frequency, using any one of the control as shown in the above-described embodiment, that is, mounting of a dielectric, loading of a metal fin, and loading of a director, Alternatively, they may be used in combination, or the distance between the feeding element and the reflector may be adjusted. The antenna device of the present invention,
With a given number of sectors, it is possible to realize a shared antenna device in which the number of frequencies to be used can be made arbitrary.

[0056]

As described above, according to the antenna device of the present invention, a sector antenna device using one antenna device at a plurality of frequencies can be easily realized without changing the size of the conventional thin sector antenna. it can. As a result,
By installing this antenna, it is possible to reduce the number of base station facilities and to reduce the size of a wireless LAN terminal that can use a plurality of services.

FIG. 9 shows a result calculated by the moment method when the parameters are given as shown in Table 2 in the antenna device having the configuration of FIG. 1 described above.
FIG. 9A shows the radiation directivity of the lower frequency f _{1 in} the horizontal plane, and FIG. 9B shows the radiation directivity of the higher frequency f _{2 in} the horizontal plane.

[0058]

[Table 2]

In this example, the ratio between the lower frequency f ₁ and the higher frequency f ₂ is 1: 2. Low frequency f ₁
In the present antenna operates as a monopole Yagi array, operating in the frequency f ₂ of the fins as corner reflector antenna to corner reflector. As shown in the figure, a sector beam having a beam width of -3 dB and a beam width of 60 degrees is obtained for each frequency.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram showing a third embodiment of the present invention.

FIG. 4 is a diagram showing a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a fifth embodiment of the present invention.

FIG. 6 is a diagram showing a sixth embodiment of the present invention.

FIG. 7 is a diagram showing a seventh embodiment of the present invention.

FIG. 8 is a diagram showing an eighth embodiment of the present invention.

FIG. 9 is a diagram illustrating an example of radiation directivity in a horizontal plane of the antenna device of the present invention.

FIG. 10 is a diagram illustrating an example of a conventional antenna device.

FIG. 11 is a diagram showing an example of a conventional antenna device.

FIG. 12 is a diagram illustrating an example of a conventional antenna device.

[Explanation of symbols]

Reference Signs List ₁ element operating at first frequency f ₁ 2 element operating at second frequency f ₂ 3 reflector 4 dielectric 5 metal fin 6 director for second sector antenna 7 operates at third frequency Element 21 Feed element 22 Wave director 23 Monopole Yagi / Uda antenna 24 Base plate 25 Partition plate 26 Cylindrical reflector 27 Horn antenna

Claims (8)

[Claims] 1. A ground plate whose surface is a conductor, a cylindrical reflecting plate whose surface is erected on the surface of the ground plate, and a metal reflecting plate on the surface of the ground plate. A plurality of partition plates whose surfaces standing up to the outside are conductors, two adjacent partition plates or their extension lines, and a region (hereinafter referred to as a sector) sandwiched between a part of the reflection plate ), And a plurality of antenna devices operating at the same frequency, each of which includes one antenna device installed in all or a part thereof and an antenna changeover switch that switches the antenna device for each sector. When a group is referred to as an antenna device group, a plurality of antenna device groups each having a different operating frequency are installed on the same ground plane, and each antenna device is located between the adjacent antenna device and another antenna device. A multi-frequency shared sector antenna device having a configuration sharing a partition plate. 2. The multi-frequency shared sector antenna device according to claim 1, wherein the antenna device of at least one of the plurality of antenna device groups includes one feed element. 3. The antenna device of at least one of the plurality of antenna device groups, wherein the antenna device includes a monopole element array including one feed element and a plurality of directors. 2. The multi-frequency shared sector antenna device according to 1. 4. An antenna device of at least one of a plurality of antenna device groups is a corner reflector antenna constituted by a feed element and two partition plates adjacent to the feed element. The multi-frequency shared sector antenna device according to any one of claims 1 to 3, characterized in that: 5. An antenna device of at least one antenna device group of the plurality of antenna device groups, comprising: a feed element; two partition plates adjacent to the feed element; and upper portions of the two partition plates. The multi-frequency shared sector antenna device according to any one of claims 1 to 3, wherein the horn antenna is constituted by a metal plate cover that covers the antenna. 6. The multi-frequency shared sector antenna device according to claim 4, wherein a dielectric is loaded on the antenna device constituting at least one antenna device group. 7. The multi-frequency shared sector antenna device according to claim 4, wherein a metal fin is loaded on the antenna device constituting at least one antenna device group. 8. The multi-frequency shared sector antenna device according to claim 4, wherein a director is mounted on at least one antenna device group constituting the at least one antenna device group. .