JPH09331207A - Dielectric antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dielectric antenna which can be controlled in sensitivity in a vertical plane over a wide extent in a horizontal plane. SOLUTION: A dielectric antenna 10 is provided with a monopole antenna 11 and a dielectric element 12 which is provided so as to cover the antenna 11. The monopole antenna 11 is nearly vertically erected on a ground plane 13 and one end of the antenna 11 is connected to a power supply source V, with the other end being opened. The antenna 10 is formed in a platy shape by laminating a plurality of dielectric layers 14a,..., 14n having different dielectric constants upon another so that a dielectric constant gradient in which the dielectric constants become smaller in steps within the range of 20 to 2 from the lowermost dielectric layer 14a which is the closest to the grounding surface 13 to the uppermost layer 14n can be formed in the antenna 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric antenna, and more particularly to a dielectric antenna for a base station which needs to strongly radiate a radio wave in a horizontal direction with respect to a ground plane.

[0002]

2. Description of the Related Art A schematic view of a conventional monopole antenna is shown in FIG. The monopole antenna 50 stands substantially vertically on the ground plane 51, one end of which is connected to the power supply V and the other end of which is open. 6 and 7 show the sensitivity in the horizontal plane and the sensitivity in the vertical plane with respect to the ground plane 51 of the monopole antenna 50, respectively. As is clear from FIGS. 6 and 7, the sensitivity is uniform in all directions of 360 ° in the horizontal plane. On the other hand, in the vertical plane, the sensitivity becomes strongest in a certain direction, and this direction has an angle with the horizontal plane, that is, the ground plane.

[0003]

However, in the above-mentioned conventional monopole antenna, when the ground plane is small in the vertical plane, the monopole antenna has sensitivity in a direction having a certain angle with respect to the ground plane. However, there is a problem that the sensitivity is weak with respect to a radio wave from a direction parallel to the ground plane, that is, a horizontal direction.

In order to solve this problem, there are antennas such as a Luneberg lens antenna and a rod lens antenna. These antennas control the sensitivity in only one direction, and the antennas in a wide range within a horizontal plane. There is a problem that the sensitivity in the vertical plane cannot be controlled.

The present invention has been made to solve the above problems, and it is an object of the present invention to provide a dielectric antenna capable of controlling the sensitivity in a vertical plane in a wide range in a horizontal plane. To aim.

[0006]

In order to solve the above-mentioned problems, the present invention comprises an antenna and a dielectric element provided so as to cover the antenna, wherein the antenna is connected to a ground plane. It is characterized in that it has sensitivity in a direction having a certain angle in a vertical plane, and the dielectric element is composed of a plurality of dielectric layers having different relative dielectric constants between adjacent layers.

Further, it is characterized in that the relative permittivity of the plurality of dielectric layers constituting the dielectric element is gradually reduced from the lowermost part close to the ground plane to the uppermost part.

Further, the plurality of dielectric layers forming the dielectric element have a substantially convex shape having an apex at a substantially central portion of the dielectric layer.

According to the dielectric antenna of the present invention, since the antenna is covered with the dielectric element composed of the dielectric layers having different relative dielectric constants between the adjacent layers, it is possible to control the relative dielectric constant of the dielectric layer. Thus, the direction in which the electric field of the antenna is concentrated can be controlled.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a sectional view of a first embodiment of the dielectric antenna of the present invention. Dielectric antenna 10
Is a monopole antenna 11 and a monopole antenna 1
1, a dielectric element 12 provided so as to cover 1.

The monopole antenna 11 is erected almost vertically on the ground plane 13, one end of which is connected to the power supply V and the other end of which is open.

The dielectric element 12 is in the form of a flat plate formed by laminating a plurality of dielectric layers 14a, ..., 14n, and these dielectric layers 14a ,. The relative permittivity is different from each other. In the first embodiment, the relative dielectric constant is gradually reduced in the range of 20 to 2 from the lowermost dielectric layer 14a close to the ground plane to the uppermost dielectric layer 14n. The gradient of is given. That is, the relative dielectric constant of the lowermost dielectric layer 14 is 2
0, the relative dielectric constant of the uppermost dielectric layer 14 is 2.

The dielectric element 12 can be manufactured by basically applying a manufacturing method similar to that of a laminated ceramic electronic component, for example. That is, a dielectric ceramic green sheet capable of giving a desired relative permittivity for each of the plurality of dielectric layers 14a, ..., 14n constituting the dielectric element 12 is prepared. Laminate the sheets and press them. This press improves the adhesion between the plurality of dielectric ceramic green sheets. Then, by firing, the dielectric element 12 having a gradient in the relative dielectric constant can be obtained.

2 and 3, this dielectric antenna 10 is shown.
The sensitivity in the horizontal plane and the sensitivity in the vertical plane with respect to the ground plane 13 are shown. However, in FIG. 2 and FIG.
The dielectric element 12 is not shown so that the sensitivity can be easily understood. 2 and 3, the solid line shows the present embodiment and the broken line shows the conventional example.

From FIG. 2, in the horizontal plane, as in the conventional case,
It is understood that the sensitivity is uniform in all directions of 360 °. On the other hand, it is understood from FIG. 3 that the sensitivity becomes the strongest in the horizontal plane, that is, in the direction substantially horizontal to the ground plane in the vertical plane.

As is clear from FIG. 3, when comparing this embodiment with the conventional example, the sensitivity in the direction substantially horizontal to the ground plane is from point B to point A, and this embodiment is stronger. ing. That is, this embodiment can receive the radio waves even if the intensity of the radio waves in the horizontal direction is weak.

As described above, according to the dielectric antenna of the first embodiment, the dielectric element covering the antenna is composed of a plurality of dielectric layers having different relative permittivities between the adjacent layers, so that the dielectric layer ratio is increased. By controlling the dielectric constant, the direction in which the electric field of the antenna is concentrated can be controlled. Therefore, it is possible to control the direction in which the sensitivity becomes highest in the vertical plane.

Further, since the relative permittivity is graded so that the relative permittivity gradually decreases from the lowermost dielectric layer close to the ground plane to the uppermost dielectric layer, the antenna has The electric field can be concentrated near the ground plane. Therefore, in the vertical plane, the sensitivity can be sharpened in the horizontal direction, that is, in the direction substantially horizontal to the ground plane, and it is possible to receive even if the intensity of the radio wave in the horizontal direction is weak.

Further, since the monopole antenna is used as the antenna, the capacitance generated between the open end and the ground plane becomes large, and the dielectric antenna can be downsized. Similar effects can be obtained with a helical antenna or the like, one end of which is connected to the power supply and the other end is open.

FIG. 4 shows a sectional view of a second embodiment of the dielectric antenna of the present invention. The dielectric antenna 20 is different from the dielectric antenna 10 of the first embodiment in that the plurality of dielectric layers 22a, ...
22n are different in that each of them has a substantially convex shape having the apex at the substantially central portion of the dielectric layers 22a, ..., 22n.

As described above, according to the dielectric antenna of the second embodiment, in addition to the effect of the first embodiment, the direction in which the electric field of the antenna is concentrated is controlled even when the ground plate is finite. It is possible to control the direction in which the sensitivity becomes the strongest in the vertical plane.

In the above embodiments, the case where the dielectric element has a flat plate shape has been described, but the dielectric element may have any shape, for example, a prismatic shape, a cylindrical shape, a pyramidal shape, a cone shape. There is a state etc.

Further, the shape of each of the dielectric layers forming the dielectric element is not limited to a flat plate shape or a substantially convex shape, and may be any shape according to the desired refraction state of radio waves. You can

Furthermore, each of the dielectric layers need not have the same thickness as each other.

Further, although the case where the antenna is a monopole antenna has been described, any antenna may be used as long as it has sensitivity in a direction having a certain angle with respect to the ground plane, for example, a helical antenna.

Further, each of the dielectric layers forming the dielectric element may be composed of a plurality of layers having the same relative dielectric constant.

[0027]

According to the dielectric antenna of the first aspect, the relative permittivity of the dielectric layer is controlled by the plurality of dielectric layers having different relative permittivities between the adjacent dielectric elements covering the antenna. As a result, the direction in which the electric field of the antenna is concentrated can be controlled. Therefore, it is possible to control the direction in which the sensitivity becomes highest in the vertical plane.

According to the dielectric antenna of the second aspect, the gradient of the relative permittivity is such that the relative permittivity gradually decreases from the lowermost dielectric layer close to the ground plane to the uppermost dielectric layer. Is given, the electric field of the antenna can be concentrated near the ground plane. Therefore, in the vertical plane,
The sensitivity can be sharpened in a direction substantially horizontal to the horizontal plane, that is, the ground plane, and it becomes possible to receive even if the strength of the radio wave in the horizontal direction becomes weak.

According to the dielectric antenna of the third aspect, the plurality of dielectric layers forming the dielectric element are formed in a substantially convex shape having the apex at the substantially central portion of the dielectric layers, and are inclined. Therefore, even when the ground plate is finite, the direction in which the electric field of the antenna is concentrated can be controlled, and the direction in which the sensitivity is strongest in the vertical plane can be controlled.

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of a dielectric antenna according to the present invention.

2 is a diagram showing the sensitivity of the dielectric antenna of FIG. 1 in a horizontal plane.

FIG. 3 is a diagram showing sensitivity in a vertical plane of the dielectric antenna of FIG.

FIG. 4 is a sectional view of a second embodiment according to the dielectric antenna of the present invention.

FIG. 5 is a schematic view showing a conventional monopole antenna.

6 is a diagram showing the sensitivity of the monopole antenna of FIG. 5 in a horizontal plane.

FIG. 7 is a diagram showing the sensitivity of the monopole antenna of FIG. 5 in a vertical plane.

[Explanation of symbols]

 10, 20 Dielectric antenna 11 Antenna (monopole antenna) 12 Dielectric element 13 Ground plane 14a, ..., 14n Dielectric layer 14a Bottom 14n Top

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yohei Ishikawa 2 26-10 Tenjin Tenjin, Nagaokakyo, Kyoto Murata Manufacturing Co., Ltd.

Claims (3)

[Claims] 1. An antenna and a dielectric element provided so as to cover the antenna, wherein the antenna has sensitivity in a direction having an angle within a vertical plane with respect to a ground plane, A dielectric antenna, wherein the dielectric element comprises a plurality of dielectric layers having different relative dielectric constants between adjacent layers. 2. The relative dielectric constant of a plurality of dielectric layers forming the dielectric element is gradually reduced from the lowermost portion close to the ground plane to the uppermost portion. Dielectric antenna. 3. The dielectric layer according to claim 1, wherein the plurality of dielectric layers forming the dielectric element have a substantially convex shape with an apex at a substantially central portion of the dielectric layer. Dielectric antenna.