JP2002261540A - Patch antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the F/B ratio of a patch antenna and, in addition, to increase the gain of the antenna in the obliquely forward direction. SOLUTION: This patch antenna is constituted, in such a way that a planar feeding element 13 is arranged at the central part, and at the same time, planar nonfeed elements 16 and 17 are arranged on both sides of the element 13 on a base plate 11, and frame-like conductive sidewalls 12 are connected to the base plate 11 in a state where the sidewalls 12 surround the elements 13, 16, and 17. In addition, plate-shaped conductors 21a and 21b are provided to respectively face the outsides of the longer sides 12a and 12b of the sidewalls 12 and the base plate 11 is connected to the conductors 21a and 21b by extending the plate 11 in its widthwise direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a patch-type antenna which is mounted on a wall or the like in a room and used as an antenna for a mobile station as a countermeasure against blind spots of, for example, a mobile phone or a mobile phone. In particular, the gain on the front side is not so much required, unnecessary radio waves in the back direction are suppressed, and a large gain is obtained in the oblique forward direction.

[0002]

2. Description of the Related Art FIG. 8 shows a configuration of a conventional patch antenna. A rectangular frame-shaped conductor side wall 12 having one end as one end is formed integrally with a peripheral edge of a rectangular base plate 11 having a length a and a width b (a> b). Side wall 12 parallel to the length direction of main plate 11
a, the height of 12b is t _1, the width direction parallel to the side wall 12c of the base plate 11, in the interior of the side wall 12 the height of the 12d is t _2, 1 side on a substantially central portion W of the base plate 11 ₁ Of the ground plane 11 through the dielectric plate 14
Is arranged in parallel with the base plate 11 at a height of h ₁ and, though not shown in the figure, penetrates the base plate 11 and the dielectric plate 14,
Power is supplied to the power feeder 15 of the power supply element 13 from the surface (back surface) of the base plate 11 opposite to the power supply element 13.

[0003] In the longitudinal direction of the base plate 11,
13 on both sides, one side is W_TwoSquare planar parasitic element 1
6 and 17 are heights h from the main plate 11, respectively._TwoIn place
It is provided in parallel with the ground plate 11 via dielectric plates 18 and 19.
The center of the planar feed element 13 and the plane parasitic elements 16 and 17
Each distance from each center is L. Where W₁>
W _Two, H₁≠ h_Two, T₁> T_TwoThere is a relationship. This package
In the case of the H-shaped antenna, a planar non-feed is provided on both sides of the planar feed element 13.
By installing the elements 16 and 17, a planar parasitic element
16 and 17 play the role of the director, and the gain in the side direction is
This has the effect of increasing. Also, the frame-shaped conductor side wall 1
2, the FB ratio (with respect to the ground plane in the front direction)
Improvement in the vertical direction on the feed element side) and gain in the side direction
Also increase.

As an example, a = 1.25λ, b = 0.48
λ, W ₁ = 0.43λ, W ₂ = 0.37λ, h ₁ = 0.
027λ, h ₂ = 0.08λ, L = 0.41λ, t ₁ =
In a plane perpendicular to the ground plane 11 at the time of 0.15λ and t ₂ = 0.09λ (λ is the working wavelength) and parallel to the arrangement direction of the elements 13, 16, 17 (the yz plane in FIG. 8C). Fig. 9
It becomes as shown in. In FIG. 9, the upper part (0 °) indicates the front direction, and the lower part (180 °) indicates the rear direction. In this numerical example, the elements 13, 16, 17 are brought as close as possible, that is, as small as possible. Note that this patch antenna is called a box-shaped planar patch antenna because it is formed in a box shape by the base plate 11 and the side wall 12.

[0005]

When such a patch-type antenna is mounted on a wall surface of a room in parallel, the gain on the front surface is not so large, and the gain on the corner of the room is larger than that on the front surface. Is desirable. Further, in order to prevent interference from outside, the FB ratio needs to be large. As can be seen from FIG. 8, the conventional patch-type antenna does not yet have a sufficient FB ratio. SUMMARY OF THE INVENTION An object of the present invention is to provide a patch antenna having a high FB ratio at the same time as achieving a high gain in a lateral direction.

[0006]

According to the first aspect of the present invention, in a patch-type antenna provided with a frame-shaped side wall and a planar parasitic element, the patch antenna is opposed to the outside of both side walls parallel to the arrangement direction of the parasitic element. And extend in the direction orthogonal to the plate conductors, plate conductors are installed, and a ground plane is extendedly connected to these plate conductors. In the second invention, a slightly larger metal box-shaped conductor is formed by a frame-shaped side wall,
In a patch-type antenna provided with a parasitic element, a box-shaped body made of a slightly larger conductor is provided so as to surround it.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 shows an embodiment of the first invention, in which parts corresponding to those in FIG. As in the case shown in FIG.
The planar parasitic elements 16 and 17 and the frame-shaped conductor side wall 12 are provided. According to this embodiment, the element 1 on the side wall 12
Sides 12a, 12b parallel to the arrangement direction of 3, 16, 17
The plate-shaped conductors 21a and 21b having a height t ₃ are provided in opposition to the base plate 11, and the base plate 11 has a length d ₁ on both sides in the width direction.
And is connected to the plate-shaped conductors 21a and 21b.
In this example, the base plate 11 has a length d on both sides in the length direction.
₁ only extended respectively, the plate-like conductor 21a, 21b is also coincident with the length of the lengthened base plate 11, thus the sides 12a of the plate-like conductors 21a, each length of 21b the side walls 12, 12
b is longer by d ₁ on both sides than the length a of. Height t
₃ opposing sides 12a of the side wall 12, is larger than the height t ₁ of 12b.

As described above, the plate-shaped conductor 21 is provided outside the side wall 12.
By providing a and 21b, radio wave radiation to the back
The function of guiding the elements to the plane parasitic elements 16 and 17 is produced, and F
The B ratio is improved, and the gain in the side direction is improved. Side wall 1
As a numerical example of each part in the case where 2 possible to approach the element 13, 16, 17 to the outside of the the box-shaped conductor, placing the plate-like conductor height t ₃ parallel to the width direction. For each size, W ₁ > W ₂ , h ₁ ≠ h ₂ , t ₁ > t ₂ , t ₃
> Relationship of t _1.

In this antenna, the plate-like conductor provided outside the box has a function of guiding radiation to the back toward the parasitic element, which leads to an improvement in the FB ratio and an increase in the gain in the side direction. In addition, there is also an effect that forward radiation is guided to the side. As an example, a = 1.25λ, b = 0.48λ, W
₁ = 0.43λ, W ₂ = 0.37λ, h ₁ = 0.027
λ, h ₂ = 0.08λ, L = 0.41λ, t ₁ = 0.1
5λ, t ₂ = 0.09λ, d ₁ = 0.027λ, t ₃ =
The directivity in the yz plane at 0.19λ is as shown in FIG. As can be understood by comparing FIG. 9 with FIG. 9, according to the first embodiment, the FB ratio is improved and the gain in the side direction is large.

The change in the FB ratio when only t ₃ is changed is shown in FIG.
Shown in The FB ratio of the antenna having the characteristics shown in FIG. 8 (FIG. 7) is 16.525 dB, and t ₃ decreases when it is increased to about 0.2λ or more.
The FB ratio cannot be expected to improve much, and the preferable value is 0.1%.
It can be seen that it is about 8λ to 0.193λ. Embodiment 2 FIG. 4 shows an embodiment of the second invention, and portions corresponding to FIG. 8 are given the same reference numerals.

In this case as well, as in the case shown in FIG.
Plate 11, planar feed element 13, planar parasitic element 16, 1
7. A frame-shaped conductor side wall 12 is provided. This embodiment
According to this, as shown in FIG.
A box 31 made of a conductor is provided so as to surround it. box
Although the bottom plate 31a of the body 31 is not shown in the drawing, for example,
The body plate is interposed, and the distance d from the main plate 11_TwoProvided
The short side plates 31b and 31c of the box 31 are
The shorter sides 12c, 12d and the distance d respectively_TwoIn
The long side plates 31d and 31e of the box-shaped body 31 facing each other
2 long sides 12a, 12b and distance d respectively_TwoIn
They are facing each other. Side plates 31c, 31b against bottom plate 31a
T_FourOf the side plates 31d and 31e with respect to the bottom plate 31a.
T _FiveAnd t_Four> T_Five, T₁+ D_Two> T_Four,
t_Two+ D_Two> T_FiveThat is, the side wall 12 protrudes from the box 31.
ing.

[0012] This configuration is a state in which the box-shaped conductor is doubly arranged.
And the FB ratio is further improved compared to the case of the first embodiment.
It is possible to make it. a = 1.25λ, b = 0.48
λ, W₁= 0.43λ, W_Two= 0.37λ, h ₁= 0.
027λ, h_Two= 0.08λ, L = 0.41λ, t₁=
0.15λ, t _Two= 0.09λ, a_Two= 1.30λ, b
_Two= 0.53λ, t_Four= 0.15λ, t _Five= 0.12
λ, d_Two= 0.025λ, that is, the side wall 12 is
Yz plane when approaching as close as possible to 3,16,17
The internal directivity was as shown in FIG. Embodiment from FIG.
The FB ratio is further improved compared to the patch antenna of No. 1
It is understood that the gain in the lateral direction is larger
It is.

The preferred numerical values shown earlier in the second embodiment
For t_FourIs a parameter, and t _FiveWhen changing
FIG. 6 shows the change in the FB ratio. From this figure, t_FourIs 0.1λ
In the following, the FB ratio becomes worse than that shown in FIG.
From t_FourMust be at least 0.1λ, and t_Five
Is larger than 0.15λ, the FB ratio is deteriorated.
Set to 5λ or less. In the second embodiment shown in FIG.
The distance d between the bottom plate 31a of the body 31 and the base plate 11_TwoSet
K_Two= 0, that is, the bottom plate 31a
It may be provided. Accordingly, the bottom plate 31a is also used as the ground plate 11.
Alternatively, the frame conductor may be doubled. Points to increase FB ratio
From d_TwoIt is better to provide_Two= 0.025
λ is preferred. The ground plate 11 and the bottom plate 31a are brought into contact with each other.
Xd = t_Four-T₁Parame
Data, yd = t_Five-T_TwoOf FB ratio to change of FB
Is shown in FIG. From FIG. 7 yd = −0.093
t_Five= 0, the FB ratio is high. In this case, FIG.
Corresponds to the first embodiment. Also, xd is 0.026λ-
It is preferably about 0.06λ, preferably xd = 0.06λ ~
About 0.053λ is good, and moreover, xd = about 0.053λ
Good degree.

In the above-described embodiment, the planar parasitic elements 16 and 17 are higher than the planar parasitic element 13 in order to turn the maximum gain direction obliquely forward.
The height 17 may be located within a range of about ± 0.1 λ or less with respect to the planar power supply element 13, that is, may be the same height, but it is better to have a difference. The parasitic elements 16 and 17 may be higher than the side wall 12. Parasitic elements 16, 17
And the distance between the feed element 13 and the near end of the element are ±
When the distance is too large, the parasitic element does not function as a director. The larger the size of the base plate 11 is, the better the size of the base plate 11 is. The shape of the planar feeding element 13 and the planar parasitic elements 16 and 17 is not limited to a square, but may be various shapes such as a rectangle and a circle. The target size is made smaller than the feed element 13. Each of the elements 13, 16, 17 is held on the base plate 11 by a dielectric plate, but may be held by other means.

[0015]

As described above, according to the present invention, by providing a plate-shaped conductor or a box-shaped conductor outside a box-shaped planar patch antenna, the lateral direction in the FB ratio and the directivity in the horizontal plane can be improved as compared with the related art. Can be improved.

[Brief description of the drawings]

FIG. 1 shows a configuration of a patch-type antenna according to a first embodiment of the present invention, wherein A is a perspective view, B is a cross-sectional view of A taken along the line BB, and C is A
5 is a sectional view taken along line CC of FIG.

FIG. 2 is a diagram showing directivity in a horizontal plane of the patch antenna according to the first embodiment of the present invention;

FIG. 3 is a view showing FB ratio characteristics with respect to a height t ₃ of a plate-like conductor of the antenna according to the first embodiment.

FIG. 4 shows a configuration of a patch antenna according to a second embodiment of the present invention, wherein A is a perspective view, B is a cross-sectional view taken along the line BB of A, and C is A
5 is a sectional view taken along line CC of FIG.

FIG. 5 is a diagram showing directivity in a horizontal plane of the patch antenna according to the second embodiment.

FIG. 6 shows F with respect to the heights t ₄ and t ₅ of the side plates of the second embodiment.
The figure which shows B ratio characteristic.

FIG. 7 is a view showing a state in which the main plate 11 is connected to the bottom plate 31a in the second embodiment
Xd = t when touched _Four-T₁, Yd = t_Five-T_Two
FIG. 4 is a diagram showing a relationship between the FB ratio and the FB ratio.

FIG. 8 shows a configuration of a conventional box-type patch antenna,
Is a perspective view, B is a cross-sectional view of A taken along line BB, and C is a cross-sectional view of A taken along line CC.

FIG. 9 is a diagram showing directivity in a horizontal plane of the conventional patch antenna shown in FIG. 8;

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshio Ebine 2-11-1, Nagatacho, Chiyoda-ku, Tokyo Inside NTT DoCoMo, Inc. (72) Inventor Hiroyuki Arai Imajuku, Asahi-ku, Yokohama-shi, Kanagawa Prefecture 615-11 Higashicho F-term (reference) 5J021 AA03 AA07 AB06 GA03 GA08 HA10 5J045 AA21 DA10 FA09 NA03 NA04 5J046 AA04 AB13 TA03

Claims (5)

[Claims] 1. A planar power feeding element disposed substantially parallel to a ground plane, two planar parasitic elements disposed substantially parallel to the ground plane on both sides of the plane power feeding element, and the ground plane. A patch-type antenna connected to the upper side and having a rectangular conductive side wall surrounding the planar feed element and the two planar parasitic elements, wherein two of the conductive side walls substantially parallel to the arrangement direction of the two parasitic elements A patch antenna, wherein two plate-shaped conductors facing each other are provided outside the side, and the ground plate is extended and connected to the two plate-shaped conductors. 2. A length of the plate-shaped conductor in a direction perpendicular to the ground plane is larger than a length of a side of the conductor side wall facing the plate-shaped conductor in a direction perpendicular to the ground plane. The patch-type antenna according to claim 1, wherein 3. A planar feed element disposed substantially parallel to the ground plane, two planar parasitic elements disposed substantially parallel to the ground plate on both sides of the planar feed element, and the ground plane. A patch antenna connected to the top and having a rectangular conductor side wall surrounding the planar feed element and the two planar parasitic elements, comprising a conductor surrounding the ground plane and the side wall except for the planar feed element side; A patch antenna having a box-like body. 4. The patch-type antenna according to claim 3, wherein the bottom plate of the box-shaped body and the ground plate are integrated. 5. The patch antenna according to claim 1, wherein a distance of the planar parasitic element from the ground plane is larger than a distance of the planar parasitic element from the ground plane.