JP2001284957A - Dielectric plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that the design of an antenna is difficult conventionally since the direction of radio waves radiated from an antenna is changed by beam shift. SOLUTION: The dielectric constant of a dielectric plate 3A in the direction of the thickness is uniform and the dielectric constant in the direction of the plane is continuously increased in the advancing direction of radio waves. Thus, beam shift can be canceled, an installation space can be effectively utilized, and handling of the antenna at the time of production/instillation can be facilitated and an emission pattern shaping can be attained without providing complicated form of a reflecting mirror surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric plate made of a dielectric material used for a radio wave structure such as an antenna or a radome that reflects or transmits radio waves.

[0002]

2. Description of the Related Art A conventional dielectric plate will be described with reference to the drawings. FIG. 5 is a diagram illustrating a path through which a radio wave propagates through a dielectric.

In FIG. 5, 1a is a first dielectric medium,
1b is a second dielectric medium, 2 is a radio wave (incident wave), P is a refracted wave, and R is a reflected wave.

When the radio wave 2 radiated from the wave source in the first dielectric medium 1a enters the boundary surface with the second dielectric medium 1b at an arbitrary angle, as shown in FIG. Is reflected in the direction of the reflection angle θ _ref. Equal to the incident angle θ _in (hereinafter referred to as a reflected wave R), and the rest is refracted in the direction of the refraction angle θ _out (hereinafter referred to as a refracted wave P). ), Penetrates into the second dielectric medium 1b.

At this time, when the refractive index of the radio wave 2 in the first dielectric medium 1a is n _in and the refractive index of the radio wave 2 _in the second dielectric medium 1b is n _out , the incident angle θ _in and the refraction angle the relationship of θ _{o ut} is represented as follows. This law states that
It is called Snell's law in optics. sin θ _in / sin θ _out = n _out / n _in

The refractive index of the radio wave 2 in each medium is expressed as follows. n _in = √ε _rin (ε _rin is the relative permittivity of the first dielectric medium 1a), n _out = √ε _rout (ε _rout is the relative permittivity of the second dielectric medium 1b)

Accordingly, the refraction angle θ _out is obtained by the following equation, and this kind of phenomenon is mainly used in a radio wave structure such as an antenna or a radome that reflects or transmits the radio wave 2. θ _out = sin ^-1 ｛√ε _rin · sin θ _in / √ε _rout ｝

Next, a conventional radio wave structure will be described with reference to the drawings. FIGS. 6, 7 and 8 are cross-sectional views of a conventional dielectric plate, a dielectric lens, and a radio wave reflection layer, respectively.

In FIG. 6, 1 denotes a dielectric medium, 2 denotes a radio wave, 3 denotes a dielectric plate, and 4 denotes air.

The dielectric plate 3 shown in FIG. 6 is in the form of a flat plate having a surface and a thickness, has uniform dielectric characteristics inside the plate, and has a relative permittivity ε _r larger than the relative permittivity ε _ra of the air 4. Is formed by the dielectric medium 1 having

In FIG. 7, reference numeral 1 denotes a dielectric medium;
Indicates a radio wave, 4 indicates air, and 5 indicates a dielectric lens.

As shown in FIG. 7, the dielectric lens 5 having a function of deflecting the traveling direction of the transmitted radio wave like an optical lens also has a uniform dielectric property inside and has a relative dielectric constant ε _ra of the air 4 as shown in FIG. It is formed in the dielectric medium 1 having a large dielectric constant epsilon _r. However, since the curvature of the inner surface is different from that of the outer surface, even if the radio wave 2 is perpendicularly incident from one of the lens walls, the radio wave 2 after being transmitted at a deflection angle determined by the relative permittivity of the dielectric lens 5 is refracted. I have. This refraction characteristic is often used for expanding the scanning angle of a beam scanning antenna.

Further, in FIG. 8, 2 indicates a radio wave, 4 indicates air, and 6 indicates a radio wave reflection layer.

The radio wave reflection layer 6 shown in FIG. 8 is formed of an electric conductor such as a metal or carbon which reflects an incident wave as it is _in a direction of a reflection angle θ _{ref .} I have.

[0015]

In a conventional dielectric plate 3 as shown in FIG. 6, when a radio wave 2 radiated from a wave source enters the dielectric plate 3 at an incident angle θ _in1 , the ratio of the dielectric plate 3 It is refracted at the refraction angle θ _out1 by the dielectric constant. Then, the radio wave 2 that has entered the dielectric plate 3 reaches the other side of the plate at an incident angle θ _in2 , is similarly refracted at a refraction angle θ _out2 due to a difference in relative permittivity, and goes out of the dielectric plate 3 again. Radiated. This is because, for example, in a spherical radome composed of a plurality of flat panels, when a radio wave 2 radiated from an antenna stored in the panel passes through each panel, a panel end portion (seam between panels) at which an incident angle becomes large. (Commonly called beam shift), especially in large radomes. As described above, the conventional radome using the dielectric plate 3 has a problem in that the direction of the radio wave 2 radiated from the antenna changes due to the beam shift, so that the electrical design of the antenna becomes difficult.

In addition, the conventional dielectric lens 5 as shown in FIG. 7 often takes an arbitrary shape such as a curved surface, so that it is difficult to make effective use of the installation space and the manufacturing method. Also became difficult. These tendencies were particularly remarkable in the large-sized dielectric lens 5.

Further, in the conventional radio wave reflecting layer 6 as shown in FIG. 8, in a rotating parabolic reflector antenna (hereinafter referred to as "parabolic antenna"), the radio wave reflection pattern of the reflecting mirror surface is changed to change the radiation pattern of the radio wave. In the case of shaping, the angle of incidence θ _in of the radio wave on the mirror surface and the reflection angle θ _ref . However, this method has a problem that it is generally difficult to design and manufacture a reflecting mirror surface shape. These tendencies were particularly noticeable in large parabolic antennas.

The present invention has been made to solve the above-mentioned problems, and provides a dielectric plate capable of canceling a beam shift, and makes it possible to make more effective use of the installation space than a conventional dielectric lens. It is possible to provide a manufacturing method and a dielectric lens that facilitates handling at the time of installation during manufacturing, and a parabolic antenna that can shape a radiation pattern without complicating the shape of a reflecting mirror surface. The purpose of the present invention is to obtain a dielectric plate.

[0019]

According to a first aspect of the present invention, there is provided a dielectric plate comprising a dielectric plate formed of a dielectric material and having the same dielectric characteristics in the thickness direction and gradually changing the plane direction. It is.

The dielectric plate according to a second aspect of the present invention has a uniform relative dielectric constant in the thickness direction and a continuous change in the relative dielectric constant in the plane direction.

According to a third aspect of the present invention, in the dielectric plate, the relative dielectric constant in the plane direction is continuously increased in the traveling direction of the radio wave.

In a dielectric plate according to a fourth aspect of the present invention, the relative permittivity in the plane direction is continuously reduced in the traveling direction of the radio wave.

A dielectric plate according to a fifth aspect of the present invention is the dielectric plate formed of a dielectric material, wherein the relative dielectric constant in the thickness direction is uniform, and the relative dielectric constant in the plane direction is continuous according to the traveling direction of the radio wave. The first dielectric plate, which has been gradually increased, has a relative dielectric constant in the thickness direction that is uniform, and the relative dielectric constant in the plane direction is continuously reduced according to the traveling direction of the radio wave.
And a second dielectric plate superimposed on the above-mentioned dielectric plate.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 A dielectric plate according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a cross-sectional configuration of a dielectric plate according to Embodiment 1 of the present invention. In the drawings, the same reference numerals indicate the same or corresponding parts.

In FIG. 1, 1A, 1B, 1C, 1D,
1E is a dielectric medium, 2 is a radio wave, 3A is a dielectric plate,
Reference numeral 4 denotes air.

The dielectric plate 3A has a dielectric medium 1
The thickness direction (Z-axis direction in the figure) of the plate formed by A to 1E has the same dielectric property, and the plane direction (X-axis direction in the figure) has any dielectric property.

That is, the dielectric plate 3A has a uniform relative dielectric constant in the thickness direction and a stepwise relative dielectric constant in the plane direction.
It grows continuously digitally. However, for the sake of explanation, the dielectric medium 1A each having uniform dielectric properties
To 1E are arranged in the plane direction.

Now, when a radio wave 2 radiated from a wave source in the air 4 (relative permittivity = ε _ra ) enters the dielectric plate 3A at an incident angle θ _{in 1} , the relative dielectric constant of the dielectric medium 1B in the vicinity thereof. rate (= ε _r1> ε _ra) by radio 2 is the refractive angle theta _out1 (<
θ _in1 ).

Then, the radio wave 2 that has entered the dielectric is converted into an adjacent dielectric medium 1C (relative permittivity = ε _{r2) in the} traveling direction.
> Ε _r1 ) at an incident angle θ _in2 , and is similarly refracted at a refraction angle θ _out2 (<θ _in2 ) due to a difference in relative dielectric constant.

Further, the radio wave 2 penetrating into the dielectric is transmitted to the adjacent dielectric medium 1D (relative permittivity = ε _{r3) in the} traveling direction.
> Arrives at an incident angle theta _in3 to epsilon _r2), is refracted by the dielectric constant of the refractive angle in the same manner by the difference θ _out3 (<θ _in3), arrives at the incident angle theta _{i n4} to the other plate, the ratio Similarly, the electric wave 2 is refracted at the refraction angle θ _out4 (> θ _in4 ) due to the difference in the dielectric constant, and the radio wave 2 is radiated again out of the dielectric plate 3A.

At this time, by appropriately designing the thickness of the dielectric plate 3A, the dimension in the plate surface direction and the relative permittivity of each of the dielectric media 1A to 1E in the plate, the radio wave 2 incident on the dielectric plate 3A is Controls the direction of travel.

That is, according to the first embodiment, the thickness direction of the dielectric plate 3A formed by the dielectric media 1A to 1E is set to the same dielectric characteristic, and the plane direction is set to an arbitrary dielectric characteristic. In-plane dielectric medium 1A-1
By appropriately designing the relative permittivity of E, the traveling direction of the radio wave 2 incident on the dielectric plate 3A can be controlled.

Embodiment 2 FIG. Embodiment 2 A dielectric plate according to Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 2 is a diagram showing a cross-sectional configuration of a dielectric plate according to Embodiment 2 of the present invention.

In FIG. 2, 1X indicates a dielectric medium, 2 indicates a radio wave, 3B indicates a dielectric plate, and 4 indicates air.

In the plane direction of the dielectric plate 3B, in which the thickness direction of the plate formed of the dielectric medium 1X has the same dielectric characteristic and the plane direction is an arbitrary dielectric characteristic, the distance from the center of the plate toward the plate end increases. Dielectric medium 1X
Is to be increased or decreased.

That is, the relative permittivity in the thickness direction of the dielectric plate 3B is uniform, and the relative permittivity in the plane direction continuously increases in an analog manner.

Now, when a radio wave 2 radiated from a wave source in the air 4 (relative permittivity = ε _ra ) enters the dielectric plate 3B at an incident angle θ _{in 1} , the relative dielectric constant of the dielectric medium 1X in the vicinity thereof rate (= ε _r1> ε _ra) by radio 2 is the refractive angle theta _out1 (<
θ _in1 ).

The radio wave 2 penetrating into the dielectric reaches the other side of the plate at an incident angle θ _in2 , and is similarly refracted at a refraction angle θ _out2 (> θ _in2 ) due to a difference in relative permittivity. The radio wave 2 is radiated outside the dielectric plate 3B.

Here, the angle between the traveling direction of the radio wave 2 radiated from the wave source and the Z axis (thickness direction axis) is defined as θ ₀ , which is defined as the beam scanning angle of the radar antenna. If the angle between a line (dotted line in the figure) connecting the tip of the beam after refraction by 3B and the wave source and the Z axis (thickness direction axis) is defined as θ, the thickness of the dielectric plate 3B and the surface direction in the plate are defined. in by appropriately designing the relative dielectric constant of the dielectric medium 1X, causes the beam scanning angle of the antenna by [Delta] [theta] (the difference between theta and theta ₀₎ is enlarged by a dielectric plate 3B.

When the dielectric medium 1X of the dielectric plate 3B according to the second embodiment is viewed microscopically, the dielectric medium 1A of the dielectric plate 3A according to the first embodiment is considered.
1 to 1E.

That is, according to the second embodiment, the same function as the dielectric lens 5 can be obtained in a planar shape by using the dielectric plate 3B, so that the conventional dielectric plate, which often takes a curved shape, is used. Compared with the body lens 5, it is possible to obtain the dielectric lens 5 that makes effective use of the installation space, a manufacturing method, and easy handling during manufacturing and installation. The same applies to the dielectric plates 3A and 3D.

Embodiment 3 Third Embodiment A dielectric plate according to a third embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a diagram showing a cross-sectional configuration of a dielectric plate according to Embodiment 3 of the present invention.

In FIG. 3, 1X indicates a dielectric medium, 2 indicates a radio wave, 3B indicates a dielectric plate, 4 indicates air, and 6 indicates a radio wave reflection layer.

A radio wave reflecting layer 6 made of an electric conductor is provided on one surface of a dielectric plate 3B having the same dielectric characteristics in the thickness direction of the plate formed of the dielectric medium 1X and the arbitrary dielectric characteristics in the plane direction. Is added.

FIG. 3 shows a dielectric plate 3B in which a radio wave reflection layer 6 is added to one surface of a dielectric plate 3B so that the relative permittivity in the thickness direction is uniform and the relative permittivity in the surface direction continuously increases.
Is shown.

Now, when a radio wave 2 radiated from a wave source in the air 4 (relative permittivity = ε _ra ) enters the dielectric plate 3B at an incident angle θ _{in 1} , the relative dielectric constant of the dielectric medium 1X in the vicinity thereof rate (= ε _r1> ε _ra) by radio 2 is the refractive angle theta _out1 (<
θ _in1 ).

[0047] Then, radio 2 has penetrated into the dielectric reaches to the radio wave reflecting layer 6 at an incident angle theta _in2, the incident angle theta _in2 matching the radio wave reflecting layer 6 on the mirror image of waves 2 which is a boundary surface '( = Θ
_in2 ), the light again enters the dielectric plate 3B, and is refracted at a refraction angle θ _out2 (= θ _in2 ).

Again, the radio wave 2 that has entered the dielectric reaches the other side of the plate at an incident angle θ _in3 , and is similarly refracted at a refraction angle θ _out3 (> θ _in3 ) due to a difference in relative permittivity.
The radio wave 2 is radiated out of the dielectric plate 3B again.

Here, when the dielectric plate 3B does not exist, the point where the radio wave 2 radiated from the wave source enters the radio wave reflection layer 6 is defined as a new wave source, and the point of the radio wave 2 radiated from the wave source is defined. The angle between the traveling direction and the Z axis (thickness direction axis) is defined as θ ₀ . Similarly, when the dielectric plate 3B exists, the dielectric plate 3B
And the line connecting the beam tip and the source after refraction by Z
The angle between the axis and the axis (thickness direction axis) is defined as θ. At this time, by appropriately designing the thickness of the dielectric plate 3B and the relative permittivity of the dielectric medium 1X in the plane direction in the plate, the reflection angle of the radio wave 2 on the radio wave reflection layer 6 is apparently Δ
is changed by θ (difference between θ and θ ₀ ).

That is, according to the third embodiment, since the radio wave reflection layer 6 formed of an electric conductor is provided on the dielectric plate 3B, it is easy to change the reflection angle of the incident radio wave 2 on the radio wave reflection layer 6. Thus, for example, it is possible to obtain a parabolic antenna capable of shaping the radiation pattern without complicating the shape of the reflecting mirror surface. In addition,
The same applies to the dielectric plates 3A and 3D.

Embodiment 4 FIG. Embodiment 4 A dielectric plate according to Embodiment 4 of the present invention will be described with reference to the drawings. FIG. 4 is a diagram showing a cross-sectional configuration of a dielectric plate according to Embodiment 4 of the present invention.

In FIG. 4, 1X denotes a dielectric medium, 1Y denotes a dielectric medium, 2 denotes a radio wave, 3B denotes a dielectric plate, 3C denotes a dielectric plate, 3D denotes a dielectric plate, and 4 denotes air.

In a dielectric plate 3D in which the thickness direction of a plate formed of a dielectric medium has the same dielectric characteristics and the surface direction has arbitrary dielectric characteristics, a plurality of dielectric plates are combined in the thickness direction. .

A dielectric plate 3D according to the fourth embodiment shown in FIG. 4 has a dielectric constant in the thickness direction which is uniform and a dielectric constant in the plane direction which is continuously increased. Are two dielectric plates 3C whose relative dielectric constants are uniform and whose relative dielectric constant in the plane direction is continuously reduced.

Now, when the radio wave 2 radiated from the wave source in the air 4 (relative permittivity = ε _ra ) is incident on the dielectric plate 3B at an incident angle θ _{in 1} , the relative dielectric constant of the dielectric medium 1X in the vicinity thereof. rate (= ε _r> ε _ra) by radio 2 is the refractive angle theta _out1 (<
θ _in1 ).

Then, the radio wave 2 that has entered the dielectric reaches the dielectric medium 1Y of the adjacent dielectric plate 3C in the traveling direction at an incident angle θ _in2 and a refraction angle θ _out2 (θ _{out 2 in} FIG. 4). = Θ _in2 ).

Further, the radio wave 2 that has entered the dielectric reaches the other end of the dielectric plate 3C at an incident angle θ _in3 ,
Similarly, the angle of refraction θ _out3 (>
θ _in3 ), and the electric wave 2 is again transmitted to the dielectric plate 3C.
Radiated out of (3D).

At this time, by appropriately designing the thickness of the dielectric plate 3D (3B and 3C) and the relative permittivity of each dielectric medium 1X and 1Y in the plane direction in the plate, the light enters the dielectric plate 3D. The traveling direction of the radio wave 2 is controlled.

As described above, the fourth embodiment
May be used instead of the dielectric plate 3B according to the third embodiment.

That is, according to the fourth embodiment, the traveling direction of the radio wave 2 incident on the dielectric plate 3D can be controlled by superposing a plurality of the dielectric plates 3B and 3C in the thickness direction. It is also possible to cancel the beam shift. Therefore, for an antenna that is housed inside a spherical radome composed of a plurality of flat panels, for example, it is not necessary to consider the beam shift caused by the radome, so that the electric design is facilitated. Further, a plurality of the same dielectric plates 3A, 3B or 3C may be stacked in the thickness direction.

[0061]

As described above, the dielectric plate according to the first aspect of the present invention has the same dielectric characteristics in the thickness direction and gradually changes the plane direction in the dielectric plate formed of the dielectric. Therefore, the beam shift can be canceled, the installation space can be effectively utilized, the manufacturing method and the handling at the time of manufacturing and installation are easy, and the radiation pattern can be shaped without complicating the shape of the reflecting mirror surface. This has the effect.

As described above, in the dielectric plate according to the second aspect of the present invention, the relative permittivity in the thickness direction is uniform and the relative permittivity in the plane direction is continuously changed, so that the beam shift can be canceled. In addition, the installation space can be effectively used, the manufacturing method and the handling during manufacturing and installation can be easily performed, and the radiation pattern can be shaped without complicating the shape of the reflecting mirror surface.

As described above, in the dielectric plate according to the third aspect of the present invention, the relative permittivity in the plane direction is continuously increased in accordance with the traveling direction of the radio wave, so that the beam shift can be canceled and the installation space can be reduced. It can be used effectively, and the manufacturing method and the handling at the time of manufacturing and installation are easy, and the radiation pattern can be shaped without complicating the shape of the reflecting mirror surface.

As described above, in the dielectric plate according to the fourth aspect of the present invention, the relative permittivity in the plane direction is continuously reduced in accordance with the traveling direction of the radio wave, so that the beam shift can be canceled and the installation space can be reduced. It can be used effectively, and the manufacturing method and the handling at the time of manufacturing and installation are easy, and the radiation pattern can be shaped without complicating the shape of the reflecting mirror surface.

As described above, in the dielectric plate according to the fifth aspect of the present invention, the relative permittivity in the thickness direction is uniform, and the relative permittivity in the plane direction is radio wave. A first dielectric plate that is continuously increased in the direction of travel of the first dielectric plate, a dielectric constant in the thickness direction is uniform, and a relative dielectric constant in the surface direction is continuously reduced in the direction of travel of the radio wave; With the second dielectric plate superimposed on the body plate, the beam shift can be canceled, the installation space can be effectively utilized, the manufacturing method and the handling at the time of manufacture and installation are easy, and the shape of the reflecting mirror surface Therefore, there is an effect that the radiation pattern can be shaped without complicating.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross-sectional configuration of a dielectric plate according to Embodiment 1 of the present invention.

FIG. 2 is a diagram showing a cross-sectional configuration of a dielectric plate according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a cross-sectional configuration of a dielectric plate according to Embodiment 3 of the present invention.

FIG. 4 is a diagram showing a cross-sectional configuration of a dielectric plate according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing the relationship among the incidence, reflection, and refraction angles of radio waves in a dielectric medium.

FIG. 6 is a diagram showing a cross-sectional configuration of a conventional dielectric plate.

FIG. 7 is a diagram showing a cross-sectional configuration of a conventional dielectric lens.

FIG. 8 is a diagram showing a cross-sectional configuration of a conventional radio wave reflection layer.

[Description of Signs] 1A, 1B, 1C, 1D, 1E, 1X, 1Y Dielectric medium, 2 radio waves, 3A, 3B, 3C, 3D dielectric plate, 4 air, 5 dielectric lenses, 6 radio wave reflection layer.

Claims (5)

[Claims] 1. A dielectric plate formed of a dielectric material, wherein the dielectric characteristics are the same in the thickness direction and the surface direction is gradually changed. 2. The dielectric constant in the thickness direction is uniform, and the dielectric constant in the plane direction changes continuously.
A dielectric plate as described. 3. The relative permittivity in the plane direction is continuously increased according to a traveling direction of a radio wave.
A dielectric plate as described. 4. The device according to claim 2, wherein the relative permittivity in the plane direction is continuously reduced according to the traveling direction of the radio wave.
A dielectric plate as described. 5. A dielectric plate formed of a dielectric material, wherein a relative dielectric constant in a thickness direction is uniform, and a relative dielectric constant in a plane direction is continuously increased in a traveling direction of a radio wave. A relative dielectric constant in a thickness direction is uniform, a relative dielectric constant in a plane direction is continuously reduced in accordance with a traveling direction of a radio wave, and a second dielectric plate superposed on the first dielectric plate is provided. A dielectric plate characterized by the above-mentioned.