JPH09191212A - Dielectric lens and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain superior characteristics and to manufacture the dielectric lent through a simple manufacture process. SOLUTION: Plural disks 1a-1e, 2f-2h, 3i, and 3j and rings 2a-2e, and 3a-3h which have different diameters are formed of dielectric sheets which are different in specific dielectric constant, and the disks 1a-1e which have a large specific dielectric constant are arranged at a center part; and the rings 2a-2e and 3a-3h which decrease in specific dielectric constant in order are fitted outside them to form coaxial multiple disks 4a-4h which have different diameters, and the coaxial multiple disks 4a-4h and single disks 3i and 3j are combined to form a hemispherical or spherical shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric lens used in a high frequency band of microwaves and millimeter waves and a method for manufacturing the same.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 4-19280 can be cited as a document relating to a conventional dielectric lens and its manufacturing method. The dielectric lens described in this publication is called a Luneberg lens,
By increasing the relative permittivity of the spherical dielectric from the surface toward the center, the incident electromagnetic wave is focused on one point of the dielectric lens. The structure has multiple concentric dielectric shells outside the central spherical dielectric nucleus, and the relative permittivity is gradually increased from the outermost dielectric shell toward the central spherical dielectric nucleus. There is something.

Further, in this method of manufacturing a dielectric lens, two or more kinds of substances having different dielectric constants and different softening points are enclosed in a spherical mold, and the spherical mold is rotated in a three-dimensional direction,
The spherical dielectric cores having different relative dielectric constants and the concentric multiple dielectric shells outside the cores are manufactured by the difference in the softening point.

[0004]

However, the conventional dielectric lens has a problem that the manufacturing process is complicated and the cost is increased.

Therefore, an object of the present invention is to provide a dielectric lens which has excellent characteristics and can be manufactured at a low cost by a simple manufacturing process, and a manufacturing method thereof.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a dielectric material which is formed by stacking a plurality of concentric multiple discs having different diameters and a single disc in a hemispherical or spherical shape. A lens, wherein the concentric multiple disc is a disc,
It is characterized by comprising a ring sequentially fitted to the outer side of the disc, and the relative permittivity of the disc and the ring are gradually reduced from the center disc to the outer periphery. It is a dielectric lens.

Further, according to the present invention, the concentric multiple discs and the single disc are provided with a hole in the central portion thereof, and a dielectric rod is inserted into the hole to form a hemispherical or spherical laminated dielectric. It is a body lens.

In the present invention, the dielectric lens constitutes a Luneberg lens, and the relative permittivity of the dielectric lens is such that the focal point of the dielectric lens is inside, on the surface or outside. The dielectric lens is characterized in that it is gradually reduced from the central portion to the outer peripheral portion.

Further, according to the present invention, a plurality of discs having different diameters and rings are formed from dielectric sheets having different relative permittivities, and a disc having a high relative permittivity is arranged in the central portion, and the discs are arranged outside the discs. A hemispherical shape characterized by forming a plurality of concentric multiple discs having different diameters by fitting rings with successively decreasing relative permittivity, and combining the concentric multiple discs and a single disc. Alternatively, it is a method for manufacturing a spherical dielectric lens.

As described above, the dielectric lens of the present invention is
Discs and rings are formed from several types of dielectric sheets with different relative permittivity, and as a single sheet, the discs and rings are molded from those with uniform relative permittivity and no relative permittivity deviation anywhere. Since the relative permittivities of these members are fitted and gradually reduced from the inside to the outside, phase error and reflection of radio waves do not occur, and the lens characteristics are excellent.

Further, a dielectric lens in which a hole is provided at the center of the disk and the hole is inserted into the dielectric rod and laminated and combined is easy to assemble.

Also, by appropriately inclining the relative permittivity of the dielectric material from the outside to the inside, the focal point of the radio wave is focused on the inside, the surface and the outside of the dielectric lens to form a so-called Luneberg lens. be able to.

Further, the method of manufacturing a dielectric lens of the present invention uses several kinds of dielectric sheets having different relative dielectric constants, and as a single sheet, the relative dielectric constant is uniform and there is no relative dielectric constant deviation. Mold the disk and ring,
These discs and rings are laminated so that their relative permittivity is reduced stepwise from the inside to the outside, so it is possible to use resin like dielectric lenses manufactured by the conventional resin molding method. The molded dielectric does not have drying distortion.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the dielectric lens of the present invention will be described below with reference to FIGS. FIG. 1 is a cross-sectional view of a dielectric lens according to this example, and FIG. 2 is an explanatory diagram of its manufacturing method. The surface of the dielectric lens 10 of the present embodiment shown in FIG. 1 is stepped hemispherical. A method of manufacturing the dielectric lens 10 will be described with reference to FIG.

First, dielectric materials such as expanded polypropylene, expanded polystyrene, porous polymer, and composite dielectric have different relative dielectric constants having a thickness of λ / 2 or less, preferably λ / 4 or less of the operating frequency. Three types of dielectric sheets (not shown) are prepared.

First, disks 1a to 1e having different outer diameters are formed from a dielectric sheet having the largest relative dielectric constant by pressing or the like.

Next, from the dielectric sheet having the second largest relative dielectric constant, the rings 2a to 2e and the disc 2f having different outer diameters are arranged.
~ 2h is molded by a press or the like.

Next, the rings 3a to 3h having different outer diameters and the single discs 3i and 3j are formed from a dielectric sheet having the third largest relative dielectric constant by pressing or the like.

Next, the rings 2a and 3a are successively fitted to the disc 1a to form a concentric multiple disc 4a. Similarly, the rings 2b and 3b are sequentially fitted to the disc 1b to form a concentric multiple disc 4b. Concentric multiple disc 4c by the same method
Form ~ 4h.

Then, the concentric multiple discs 4a to 4h and the single discs 3i and 3j are sequentially laminated with their central axes being the same to form a hemispherical dielectric lens 10 as shown in FIG.

An adhesive may be used for the lamination, if necessary. Further, in order to facilitate the positioning of the stack, as shown in FIG. 3, the discs 1a to 1e, 2f to
Make holes in the center of 2h, 3i and 3j,
The hemispherical dielectric lens 20 may be assembled by inserting these holes into the dielectric rod 5.

Further, as shown in FIG. 4, the discs 6a and 6b are
And a convex portion a and a concave portion b which are fitted to the rings 7a, 7b, 8a and 8b, respectively, or a convex ring and a concave ring are provided, and the convex portion a and the concave portion b or the convex ring and the concave ring are fitted. Alternatively, hemispherical or spherical dielectric lenses may be assembled.

In this embodiment, three types of dielectric sheets having different permittivities are used to reduce the relative permittivity from the inside to the outside of the dielectric lens. In the Luneberg lens, the permittivity εr is a function εr (r) of the lens radius r,
The focus of the radio wave incident on the dielectric lens is appropriately selected depending on whether the focus is inside the dielectric lens, on the surface or outside.

The method of manufacturing a dielectric lens according to the present invention is
Since the disk and the ring are press-molded from a dielectric sheet having a thickness equal to or less than λ / 2 of the operating frequency, so-called shrinkage (distortion) caused by the drying time of the resin is compared to the conventional manufacturing method by resin molding. ) Does not occur, and thus the manufactured dielectric lens has excellent dimensional accuracy, and the relative dielectric constant deviation is eliminated in the disk and ring having the same relative dielectric constant, and the lens characteristics are excellent.

Further, since the thickness of the molded dielectric sheet is not more than λ / 2 of the used frequency, the surfaces of the dielectric lenses 10 and 20 are stepwise, but electrically the surfaces are spherical. Will be equivalent. However, when the thickness of the molded dielectric sheet becomes thicker than λ / 2 of the operating frequency and this thickness affects the characteristics of the dielectric lens, as shown in FIG. Alternatively, a dielectric lens 30 in which the boundary surfaces of the rings 2 and 3 are spherical may be used.

The spherical dielectric lens can be easily manufactured by laminating the hemispherical dielectric lenses shown in FIG.

[0027]

The dielectric lens of the present invention is manufactured by fitting a disk and a ring formed from a dielectric sheet having a uniform relative dielectric constant to form a concentric multiple disk, and stacking these. The relative permittivity is reduced from the inside to the outside, so there is no relative permittivity deviation in a disc or ring with the same relative permittivity, no phase error and reflection of radio waves, and lens characteristics It will be excellent.

According to the method of manufacturing a dielectric lens of the present invention, a disk and a ring are formed from dielectric sheets having different relative permittivities, these are fitted to each other to form a concentric multiple disk, and these are laminated. As a result, a dielectric lens having an inclined relative dielectric constant is formed, so that a drying time of the dielectric resin is not required as compared with the conventional injection molding method, and the dielectric resin caused by the drying time of the dielectric resin is not required. A dielectric lens having excellent characteristics can be easily manufactured by a simple process without distortion.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment of a dielectric lens of the present invention.

FIG. 2 is an explanatory view of a method of manufacturing the dielectric lens shown in FIG.

FIG. 3 is a sectional view of a second embodiment of the dielectric lens of the present invention.

FIG. 4 is a partial cross-sectional exploded explanatory view of a modification of the dielectric lens of the present invention.

FIG. 5 is a sectional view of a third embodiment of the dielectric lens of the present invention.

[Explanation of symbols]

 1a-1e, 2f-2h Discs 2a-2e, 3a-3h Rings 3i, 3j Single disc 4a-4h Concentric multiple discs 10, 20, 30 Dielectric lens

Claims (4)

[Claims] 1. A dielectric lens formed by stacking a plurality of concentric multiple discs having different diameters and a single disc in a hemispherical or spherical shape, wherein the concentric multiple discs are a disc and It is characterized by comprising a ring sequentially fitted to the outer side of the disc, and the relative permittivity of the disc and the ring are gradually reduced from the center disc to the outer periphery. Dielectric lens to do. 2. The hemispherical or spherical laminated structure according to claim 1, wherein a hole is provided in the central portions of the concentric multiple discs and the single disc, and a dielectric rod is inserted into the holes to form a hemisphere or a sphere. Dielectric lens. 3. The dielectric lens according to claim 1 or 2 constitutes a Luneberg lens, and the dielectric constant of the dielectric lens is such that the focal point of the dielectric lens is inside, on the surface or outside. As described above, the dielectric lens is characterized in that it is gradually reduced from the central portion toward the outer peripheral portion. 4. A plurality of discs and rings having different diameters are formed from dielectric sheets having different relative permittivities, a disc having a high relative permittivity is arranged at the center, and the relative permittivity is successively arranged outside the discs. Characterized by forming a plurality of concentric multiple discs having different diameters by fitting a ring for reducing the number of concentric multiple discs and combining the concentric multiple discs with a single disc. Body lens manufacturing method.