JP2004222157A - Radio wave converging/deflecting body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio wave converging/deflecting body that is difficult to be damaged even when the radio wave converging/deflecting body is manufactured by press molding or the like. <P>SOLUTION: In this radio wave converging/deflecting body, a dielectric substrate 2 is provided with recess parts 3. Since the radio wave converging/deflecting body is provided with the recess parts 3, a radio wave can be converged. The surface roughness R<SB>a</SB>of the surface of the dielectric substrate 2 is ≥0. 03μm, and R<SB>a</SB>and a wavelength λ of the radio wave satisfy (R<SB>a</SB>/λ) ≤ 0. 01. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radio wave converging / deflecting body in a microwave and millimeter wave region used for communication or broadcasting.
[0002]
[Prior art]
Today, due to the demand for high-speed and large-capacity communication, high-frequency communication that transmits and receives radio waves using microwaves and millimeter waves is rapidly expanding. Since the microwave and millimeter wave have a wavelength of several millimeters to several tens of millimeters, it is possible to easily produce a Fresnel lens or the like that focuses a radio wave, and a radio wave converging / deflecting body such as a Fresnel lens using a dielectric substrate. Have been proposed (see, for example, Patent Document 1).
[0003]
A conventional radio wave converging / deflecting body includes the above-mentioned Fresnel lens provided with a step or the like in the thickness direction of the dielectric substrate. This Fresnel lens has a phase compensation function for correcting a phase difference of radio waves.
[0004]
The radio wave converging / deflecting body such as the conventional Fresnel lens is manufactured by cutting a dielectric substrate using a grindstone or the like, or by press molding or the like. However, since the surface of the conventional radio wave converging / deflecting body is a mirror surface, when it is manufactured by press molding or the like, there is a problem in that it adheres to the mold and breaks or cracks such as cracks or cracks.
[0005]
The material of the dielectric substrate will be described in more detail as glass, for example. When the mold and the glass are in close contact during molding, the mold and the glass are partially or physically fixed, or when the glass is cooled after molding. A negative pressure space is created at the interface between the glass and the mold due to the difference in the coefficient of linear expansion of the mold, and the adhesion between the mold and the dielectric substrate may increase due to atmospheric pressure. The body substrate and the mold may stick to each other temporarily or permanently.
[0006]
In that case, it is necessary to forcibly peel the dielectric substrate from the mold, but there is a problem that the dielectric substrate or the mold is damaged when releasing the mold. Further, when the dielectric substrate is hot at the time of mold release, there is a problem that the dielectric substrate is deformed by the adhesive force between the mold and the glass.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 4-134909 (Claims, FIGS. 3 and 8)
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide a surface shape of the radio wave converging / deflecting body which is not easily damaged during molding.
[0009]
[Means for Solving the Problems]
The present invention has been made to solve the above-mentioned problems, and the dielectric substrate is provided with at least one selected from a concave portion, a convex portion, a step and a slope, and these concave portion, convex portion, step or In the radio wave converging / deflecting body that converges or deflects radio waves by providing a slope,
Surface roughness R _a of the dielectric at least a portion of the surface of the substrate is not less than 0.03 .mu.m, and,
The surface roughness _Ra and the wavelength λ of the radio wave are
(R _a /λ)≦0.01,
The present invention provides a radio wave convergence / deflection body characterized by satisfying
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 shows a configuration of an embodiment of a radio wave converging / deflecting body according to the present invention, and is a cross-sectional view seen from a direction perpendicular to the thickness direction of a dielectric substrate 2. FIG. 3 shows a configuration of an embodiment different from that in FIG. 1 and is a cross-sectional view seen from a direction perpendicular to the thickness direction of the dielectric substrate 2. In the following description, unless otherwise specified, a direction refers to a direction on the drawing.
[0011]
As shown in FIG. 1, in the present invention, for example, a recess 3 is provided in the dielectric substrate 2, and by providing the recess 3, radio waves are converged or deflected. In the example shown in FIG. 1, the dielectric substrate 2 is provided with the concave portion 3. However, the present invention is not limited to this, and may be a convex portion, a step or a slope instead of the concave portion 3. It may be at least one selected from a step and a slope. In the case of converging radio waves, it is preferable that at least one selected from a concave portion, a convex portion, a step, and a slope is provided on the dielectric substrate 2 in a ring shape.
[0012]
In the present invention, the surface roughness _{R a} of the surface 1 of the dielectric substrate 2 is not less than 0.03 .mu.m. If it is this range, when cooling at the time of molding, for example, a gap between the dielectric substrate and the mold is caused by a difference in linear expansion coefficient between the dielectric substrate made of glass or the like and the mold. As a result, the dielectric substrate and the mold are easily separated.
[0013]
A radio wave converging / deflecting body of the present invention having a cross section as shown in FIG. 1 converges the radio wave, and the converged radio wave is received by a radiator (not shown) and measured, gain − (R _a / λ ( The characteristics of wavelength)) are shown in FIG. As shown in FIG. 2, when (R _a / λ) is 0.01 or more, the gain is reduced by about 1.2 dB or more, compared to when (R _a / λ) is 0.00. Further, when (R _a / λ) is 0.007 or more, the gain is reduced by about 0.5 dB or more. Above, the characteristic shown in FIG. 2, and _(R a _/λ)≦0.01, if this range, good communication. A preferred range is (R _a /λ)≦0.007.
[0014]
By the way, for example, when a radio wave converging body is used at a frequency of 26 GHz, the wavelength is 11.5 mm. Therefore, when (R _a / λ) is 0.01, R _a is 115 μm. For example, when a radio wave converging body is used at a frequency of 26 GHz, the wavelength is 11.5 mm. Therefore, when (R _a / λ) is 0.007, Ra is 81 μm.
[0015]
FIG. 3 is a plan view of an embodiment (phase compensation type aspherical Fresnel lens) of the radio wave converging / deflecting body of the present invention. FIG. 4 is a view from the center to the periphery of the phase compensation type aspherical Fresnel lens shown in FIG. It is 0-0 'sectional drawing cut in the thickness direction. As shown in FIG. 3, this phase compensation type aspheric Fresnel lens constitutes zones z1 to z6 for correcting the phase of radio waves by radio wave diffraction elements using the thickness of a dielectric glass or the like. A concentric fresnel zone is formed as shown in FIG.
[0016]
The material of the dielectric substrate 2 in the present invention may be any dielectric material such as glass, a plastic film or plate such as PET, or a synthetic resin such as acrylic.
[0017]
【Example】
The present invention will be described below with reference to examples, but the present invention is not limited to these examples, and various improvements and modifications are also included in the present invention as long as the gist of the present invention is not impaired. Hereinafter, embodiments will be described in detail with reference to the drawings.
[0018]
The radio wave converging / deflecting body (phase compensation aspheric Fresnel lens) shown in FIGS. 1, 3, and 4 was produced by press molding. The dielectric substrate 2 is made of glass (relative permittivity is 7.0). The thickness d1 was 7.2 mm, the thickness d2 was 2.8 mm, and the total thickness d3 was 10.0 mm. The radii of the zones z1 to z6 are as shown below. The frequency was 26 GHz and the focal length F was 100 mm. There were no cracks, cracks or scratches on the step. Moreover, it was able to communicate well.
[0019]
r1 49.4 mm,
r2 71.7 mm,
r3 90.1 mm,
r4 106.6 mm,
r5 121.9mm,
r6 136.5 mm,
R _a 50.0 μm,
(R _a / λ) 0.0043.
[0020]
【The invention's effect】
In the present invention, even when manufactured by press molding or the like, it is difficult to adhere to the mold, and breakage or scratches such as cracks and cracks are less likely to occur.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an embodiment of a radio wave converging / deflecting body according to the present invention as viewed from a direction perpendicular to a thickness direction of a dielectric substrate 2;
FIG. 2 shows a gain − (R) obtained by converging a radio wave by the radio wave converging / deflecting body of the present invention having a cross section as shown in FIG. 1, and receiving and measuring the converged radio wave by a radiator (not shown). _a / λ (wavelength)).
FIG. 3 is a plan view of another embodiment (phase compensation aspheric Fresnel lens) different from FIG. 1;
4 is a 0-0 ′ cross-sectional configuration diagram of zones z1 to z6 in which the phase of a radio wave is corrected by a radio wave diffraction element using the thickness of glass as a dielectric in the example shown in FIG. 3;
[Explanation of symbols]
1: Surface 2: Dielectric substrate 3: Recess

Claims (1)

The dielectric substrate is provided with at least one selected from a concave portion, a convex portion, a step, and a slope, and is provided with the concave portion, the convex portion, the step, or the slope, thereby converging or deflecting the radio wave. In the deflector,
Surface roughness R _a of the dielectric at least a portion of the surface of the substrate is not less than 0.03 .mu.m, and,
The surface roughness _Ra and the wavelength λ of the radio wave are
(R _a /λ)≦0.01,
Radio wave convergence / deflection body characterized by satisfying

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