Electricity: conductors and insulators – Anti-inductive structures – Conductor transposition
Patent
1998-10-05
2000-11-14
Cuchlinski, Jr., William A.
Electricity: conductors and insulators
Anti-inductive structures
Conductor transposition
174 35MS, 174 521, 428195, 428441, H05K 900
Patent
active
061473022
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a novel electroconductive pattern, and more specifically to a novel electroconductive loop pattern which shields electromagnetic waves of a specific frequency range. The present invention also relates to a frequency-selective electromagnetic wave shielding material comprising the electroconductive loop pattern.
TECHNICAL FIELD
In recent years, it has become necessary to protect information of an office, or to prevent mixing, of communication lines, due to the progress of the communication systems such as portable telephone, radio LAN, and the like. Buildings are, therefore, usually surrounded with a grounded electroconductive material, and isolated from electromagnetic waves generated inside and outside the buildings.
Conventional electromagnetic wave shielding materials reflect electromagnetic waves across all frequency ranges. Therefore, when the conventional electromagnetic wave shielding materials are used on a wall or a window of a building, TV ghosting may occur at an adjacent area of the building due to the reflection of TV signals. In order to solve this problem, it is desirable to have an electromagnetic wave shielding material which selectively reflects electromagnetic waves having frequencies of 1 to 6 GHz which are used as communication waves, and which does not reflect, but passes electromagnetic waves having frequencies of 0.08 to 0.8 GHz, the frequency range of TV waves
Japanese Patent Application No. 19739/1988 discloses such frequency-selective electromagnetic wave shielding materials, that is, a dichroic mirror in which layers having different dielectric constants are layered, a material in which ring-shaped copper foils are evenly dispersed, and an electromagnetic wave shielding material in which a thin film electroconductor using a skin effect is employed. However, the electromagnetic wave shielding materials have insufficient shielding capability, and are not practical. Additionally, the electromagnetic wave shielding materials' compositions are complicated, and are difficult to manufacture.
It is known that a pattern as shown in FIGS. 1A and B, having linear or curved electro conductive segments and a gap between the electroconductive segments in the direction of an electric field E, has the property that it only reflects electromagnetic waves in a resonant region, and passes electromagnetic waves in a nonresonant region.
The selective reflection property against the electromagnetic waves of a specific frequencies which is attributed to the LC resonant pattern as described above, is applied to a subreflector of a two frequency shared antenna equipped with an artificial satellite. In this case, a ring pattern as shown in FIG. 2A, or a Jerusalem cross pattern, as shown in FIG. 2B, is formed on a surface of the subreflector by using metal foil (e.g., Electronic Information Communication Society, Technical Report A, pages 86 to 72, 1986-09).
However, these patterns aim at reflecting electromagnetic waves having a frequency range of 7 to 80 GHz, and are unusable in electromagnetic wave shielding materials aimed at reflecting a communication wave. These patterns also have insufficient shielding capability, because it is difficult to sufficiently shield the communication waves, which have efficient permeabilities.
SUMMARY OF THE INVENTION
The object of the present invention is to solve these conventional problems, and to provide an electroconductive loop pattern which selectively shields communication waves, and has sufficient electromagnetic wave shielding capability, and to provide a frequency-selective electromagnetic wave shielding material using the loop pattern.
The present invention provides an electroconductive loop pattern consisting of a plurality electroconductive loop parts which are spatially allocated, wherein each of the electroconductive loop parts is insulated, and circumference parts of adjacent electroconductive loop parts are as near as possible to each other, thereby achieving the above-described object.
BRIEF DES
REFERENCES:
patent: 3253082 (1966-05-01), Beset
patent: 3821463 (1974-06-01), Bakker
patent: 5239125 (1993-08-01), Savage et al.
patent: 5895885 (1999-04-01), Kunkel
Iida Shoichi
Koso Toshiki
Matsuo Seiichi
Cuchlinski Jr. William A.
Mancho Ronnie
Nippon Paint Co. Ltd.
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