JPH0794935A - Planar antenna - Google Patents

Abstract

PURPOSE:To extend a frequency band with a low axial ratio and to expand a frequency band with high matching by preparing at least one radiation conductor plate provided with specific peripheral conductor plates arranged along the periphery of the radiation conductor plate. CONSTITUTION:This plane antenna has a feeding means consisting of dielectric 6, a microstrip line 7 and an earth conductor plate 4 provided with a slot 5 and a radiation conductor plate 1 arranged on the earth conductor plate 4 via air as insulating body to which high frequency power is fed from the feeding means. The plate 1 has a circular shape and is provided with two peripheral conductor plates 2 extended from mutual opposed positions on the periphery of the plate 1 by length L in the same peripheral direction along the peripheral edge of the plate 1. The length L is about 0.45 times of propagation wavelength. Since at least one radiation conductor plate 1 provided with two peripheral conductor plates 2 extended by length >0.4 propagation wavelength the peripheral edge of the plate 1 is prepared, a circularly polarized wave can be radiated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat antenna having a radiation conductor plate and a power feeding means for feeding high frequency power to the radiation conductor plate.

[0002]

22 is a perspective view showing an example of a conventional planar antenna of this type. In FIG. 22, the planar antenna is a ground conductor plate 4 having a plate-shaped dielectric body 6, a microstrip line 7 formed on the lower surface of the dielectric body 6, and a slot 5 formed on the upper surface of the dielectric body 6. It has a power feeding means including a ground plate 4) and a circular radiation conductor plate 21 (patch 21) arranged on the ground plate 4. Two notches facing each other in the diametrical direction are formed on the peripheral edge of the patch 21.

The planar antenna configured as described above is
A microwave signal is input to the power feeding means and the patch 21 is excited through the slot 5 to radiate circularly polarized waves.

In addition to the above-mentioned planar antenna, a planar antenna having a cutout portion on a radiation conductor plate is disclosed in Japanese Patent Laid-Open No. 3-1453
No. 05 publication.

[0005]

However, conventional planar antennas that generate circularly polarized waves, including the above planar antenna, are
There is a problem that the frequency band with a low axial ratio (good elliptic polarization ratio) is narrow.

Further, there is a problem that the frequency band in which the matching can be achieved is narrow.

An object of the present invention is to provide a planar antenna having a wide frequency band with a low axial ratio.

Another object of the present invention is to provide a flat antenna having a wide frequency band with good matching.

[0009]

According to the present invention, a power feeding means provided with a ground conductor plate and a radiation arranged on the ground conductor plate via a dielectric and supplied with high frequency power from the power feeding means. A planar antenna having a conductor plate, wherein the radiation conductor plate is provided with an outer peripheral conductor plate extending along a periphery thereof to a length of 0.4 wavelength or more of a propagation wavelength corresponding to the relative permittivity of the dielectric. A planar antenna is obtained which has at least one layer.

The radiation conductor plate may have any one of a circular shape, an oval shape and a rectangular shape.

Further, the radiating conductor plate may include two outer peripheral conductor plates so as to extend in the same circumferential direction from positions opposite to each other on their peripheral edges.

Further, it is also possible that the radiation conductor plates are laminated in two or more layers, the radiation conductor plates of each layer have the same type of shape, and there is a relative positional relationship with a predetermined rotation angle about the center of the shape. Good.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A planar antenna according to an embodiment of the present invention will be described below with reference to the drawings. In each drawing of each embodiment, the same parts or similar parts as in the conventional example and the same parts or similar parts in different embodiments are designated by the same reference numerals.

[Embodiment 1] FIG. 1 is a perspective view showing a planar antenna according to Embodiment 1 of the present invention. In FIG.
This planar antenna is composed of a feeding means including a dielectric 6, a microstrip line 7 and a ground conductor plate (hereinafter referred to as a ground plate) 4 having a slot 5, and an air as a dielectric on the ground plate 4 via air. Radiating conductor plate (hereinafter referred to as a patch), which is arranged as
1 and.

Referring also to the plan view of FIG. 2, the patch 1
Has a circular shape, and is provided with two outer peripheral conductor plates (hereinafter referred to as loops) 2 that extend from opposite positions of their peripheral edges to the length L in the same circumferential direction along the peripheral edges. Here, the length L is about 0.45 of the propagation wavelength (about 0.4 of the propagation wavelength).
5 times as long).

The propagation wavelength (λ) used in this embodiment is defined by the relative permittivity of the dielectric material related to the conductor, εr,
If the spatial wavelength is λ ₀ , it can be obtained by Equation 1.

[0017]

[Equation 1]

Further, in the present planar antenna, it is possible to use a power feeding means to the patch 1 different from the configuration of FIG.
That is, as shown in the perspective view of FIG. 3 and the vertical sectional view of FIG. 4, power is supplied to an arbitrary power feeding point 3 of the patch 1 through a hole formed in the ground plate 4 ′ under the patch 1. You may take

Next, the electrical characteristics of the planar antenna shown in FIG. 1 were measured.

In FIG. 1, the diameter of the patch 1 of the planar antenna is about 0.45 wavelength of the propagation wavelength, the length L of the loop 2 is about 0.45 wavelength of the propagation wavelength as described above, and the rotation of the loop 2 with respect to the slot 5 is performed. The angle θ is 45 °, the distance d between the patch 1 and the ground plate 4 is about 0.02 wavelength of the propagation wavelength, and the length S of the slot 5 is about 0.25 wavelength of the propagation wavelength. The ratio and the reflection loss, which is a measure of matching, were measured.

The relationship between frequency and axial ratio is shown in FIG. Figure 5
In a relatively wide frequency band of 1.55 to 1.60 GHz, a good result with an axial ratio of 6 dB or less was obtained. A band having an axial ratio of 6 dB or less is about 3.2%.

FIG. 6 shows the relationship between the frequency of radio waves and the reflection loss. In FIG. 6, 1.45 to 1.67 GHz
Reflection loss is -11d in the relatively wide frequency band of
Good results of B or less were obtained. Reflection loss is -11dB
The following band is about 13%.

[Embodiment 2] FIGS. 7 to 9 are plan views showing examples of the shape of the patch of the planar antenna according to Embodiment 2. As shown in FIG.
7 to 9, each patch 10 has an elliptical shape as an example of an oval shape. Two loops 11, 12, and 13 are added to each patch 10 from positions opposite to each other on the periphery of the patch 10 along the elliptical periphery in the same circumferential direction and have a length of about 0.45 wavelength of the propagation wavelength. Extends to.

The means for supplying power to these patches 10 may have the same structure as in the first embodiment.

[Third Embodiment] FIGS. 10 to 13 show a third embodiment.
4 is a plan view showing an example of the shape of a patch of the planar antenna according to FIG. 10 to 13, the patch 14 or 16
Has a square as an example of a square.

Then, in FIGS. 10 and 11, two loops 15 are added to each patch 14, and
Two loops 17 added to the patch 16 extend from the opposite positions of the periphery of the patch 14 or 16 to the length of about 0.45 wavelength of the propagation wavelength in the same circumferential direction along the periphery of the square. There is.

In addition, in FIG. 12 and FIG. 13, two loops 18 are added to each patch 14 or 16.
Extend from opposite positions of the periphery of the patch 14 or 16 along the periphery of the square in the same circumferential direction in an arc shape to a length of about 0.45 wavelength of the propagation wavelength.

Incidentally, the power feeding means to these patches 14 or 16 can also have the same construction as in the first embodiment.

[Fourth Embodiment] FIG. 14 and FIG. 15 are plan views showing a configuration example of a loop of a planar antenna according to a fourth embodiment. In FIGS. 14 and 15, only one loop 2 or loop 15 is added to each of the patch 1 having a circular shape and the patch 14 having a square shape and extending along the peripheral edge to a length of about 0.45 wavelength of the propagation wavelength. ing.

Incidentally, the power feeding means to these patches 1 or 14 can also have the same construction as in the first embodiment.

Here, in each of Examples 1 to 4, the length of the loop added to the patch is set to 0.4 of the propagation wavelength.
Although the loop length is set to 5 wavelengths, the loop length is approximately 20% or more above and below the half wavelength of the propagation wavelength, that is, at least 0.4 wavelength or more, and a wide frequency band with a low axial ratio and a good matching frequency band can be obtained. It was found from the experimental results that it was preferable.

[Fifth Embodiment] FIGS. 16 to 19 show a fifth embodiment.
FIG. 6 is a plan view showing an example of the shape of a loop of the planar antenna according to FIG.

16 and 17, the patch 1,
For each patch 14, from the opposite positions of the periphery,
Loops 19 and 20 are added to each other so as to draw spirals in the same circumferential direction along the peripheral edge and extend to a length of 0.45 wavelength or more of the propagation wavelength.

Further, in FIGS. 18 and 19, a patch 19 and a loop 20 are added to the patch 1 and the patch 14, respectively, so as to draw a spiral along the periphery and extend to a length of 0.45 wavelength or more of the propagation wavelength. ing.

Incidentally, the power feeding means to these patches 1 or 14 can also have the same construction as in the first embodiment.

[Sixth Embodiment] FIGS. 20 and 21 are perspective views showing a configuration example of a planar antenna according to a sixth embodiment.

20 and 21, each of the planar antennas has the same circular shape on the ground plate 4 of the feeding means, and each patch 8 has two loops.
The patches 9 are two-layered and arranged at intervals.

In the planar antenna of FIG. 20, the patch 8 and the patch 9 have a relative positional relationship such that the positions of the added loops are the same.

In addition, the planar antenna of FIG.
The patch 9 and the patch 9 are in a relative positional relationship in which the positions of the added loops form a rotation angle of 90 ° about the center of the circle.

In the sixth embodiment, the two layers of the patch 8 and the patch 9 may have the same type of shape and need not have the same size. The shape of the patch is not limited to the circular shape, but may be an oval shape, a square shape, or the like. When the patch shape is square, the relative positional relationship between the patches is set with the center of the shape such as the intersection of the diagonals as the axis. Also, the relative positional relationship between the patches is 9
The rotation angle is not limited to 0 °.

Also in the planar antennas according to the second to sixth embodiments described above, the axial ratio of the polarization circle to the frequency of the radio wave and the reflection loss were measured in the same manner as in the first embodiment. The results were obtained.

[0042]

Since the planar antenna of the present invention has at least one layer of the radiation conductor plate having the outer periphery conductor plate extending along the periphery of the radiation conductor plate to the length of 0.4 wavelength or more of the propagation wavelength, Of course, circularly polarized waves can be radiated, and the frequency band with a low axial ratio and the frequency band with good matching are wide.

[Brief description of drawings]

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

FIG. 2 is a plan view showing a patch of the planar antenna shown in FIG.

FIG. 3 is a perspective view showing an example in which the power feeding means of the planar antenna according to the first embodiment of the present invention is different.

4 is a vertical cross-sectional view of the planar antenna shown in FIG.

5 is a diagram showing reflection loss of the planar antenna shown in FIG.

FIG. 6 is a diagram showing an axial ratio of the planar antenna shown in FIG.

FIG. 7 is a plan view showing a patch of a planar antenna according to a second embodiment of the present invention.

FIG. 8 is a plan view showing another example of the patch shown in FIG.

9 is a plan view showing another example of the patch shown in FIG. 7. FIG.

FIG. 10 is a plan view showing a patch of a planar antenna according to a third embodiment of the present invention.

FIG. 11 is a plan view showing another example of the patch shown in FIG.

12 is a plan view showing another example of the patch shown in FIG.

13 is a plan view showing another example of the patch shown in FIG.

FIG. 14 is a plan view showing a patch of a planar antenna according to a fourth embodiment of the present invention.

FIG. 15 is a plan view showing another example of the patch shown in FIG.

FIG. 16 is a plan view showing a patch of a planar antenna according to a fifth embodiment of the present invention.

FIG. 17 is a plan view showing another example of the patch shown in FIG.

FIG. 18 is a plan view showing another example of the patch shown in FIG.

FIG. 19 is a plan view showing another example of the patch shown in FIG.

FIG. 20 is a perspective view showing a planar antenna according to a sixth embodiment of the present invention.

21 is a perspective view showing another example of the planar antenna shown in FIG. 20. FIG. FIG.

FIG. 22 is a perspective view showing a conventional planar antenna.

[Explanation of symbols]

 1 patch 2 loop 3 feeding point 4, 4'ground plate 5 slot 6 dielectric 7 microstrip line 8-10 patch 11-13 loop 14 patch 15 loop 16 patch 17-20 loop 21 patch

Claims (4)

[Claims] 1. A planar antenna comprising: a feeding means having a ground conductor plate; and a radiation conductor plate which is arranged on the ground conductor plate via a dielectric and to which high-frequency power is fed from the feeding means. As the radiation conductor plate, at least one having an outer peripheral conductor plate extending along the periphery thereof to a length of 0.4 wavelength or more of a propagation wavelength corresponding to the relative permittivity of the dielectric body is used.
A planar antenna having layers. 2. The planar antenna according to claim 1, wherein the radiating conductor plate has any one of a circular shape, an oval shape, and a rectangular shape. 3. The planar antenna according to claim 1, wherein the radiating conductor plate is provided with two outer peripheral conductor plates so as to extend in the same circumferential direction from positions opposite to each other at their peripheral edges. 4. The radiation conductor plates are laminated in two or more layers, and the radiation conductor plates in each layer have the same type of shape, and have a relative positional relationship with a predetermined rotation angle about the shape center as an axis. The planar antenna according to any one of 3 to 3.