JPH06132688A - Electromagnetic shielding structure - Google Patents

Abstract

PURPOSE:To allow electromagnetic shielding by making a length of a gap to be generated in the junction part about 1/2 of a wavelength of a shielding electromagnetic wave so as to prevent leakage of the electromagnetic wave in the junction part. CONSTITUTION:In the electromagnetic shielding structure shielding an electromagnetic wave by joining a plurality of shield plates, a junction end of the shield plate 1 is formed into an about U-shaped section, the junction end of a shield plate 2 is inserted between said U-shaped upper and lower plates 5, 7 so as to make the length as seen from the sectional direction of a gap 10 to be generated between the junction end of the shield plate 1 and the junction end of the shield plate 2 about 1/2 of the wavelength of the shielding electromagnetic wave in order to perform electromagnetic shielding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic shield structure for shielding electromagnetic waves such as microwaves.

[0002]

2. Description of the Related Art Conventionally, when the shield plates are joined to each other, the shield plates are mechanically fitted to each other so as not to create a gap, copper foil tape is attached, or soldering is performed. The electromagnetic shield is made by blocking the gap between the joints and preventing the electromagnetic waves from leaking.

[0003]

However, in the method of mechanically fitting the joint portion, a gap is apt to be generated, and in the method of attaching the copper foil tape, the gap is similarly generated due to variation due to floating of the copper foil tape or the like. In addition, there are problems that it is easy, and that the joining method by soldering limits the materials used and takes time. SUMMARY OF THE INVENTION It is an object of the present invention to prevent electromagnetic waves from leaking and electromagnetically shield them even if a gap is created between the joints of shield plates.

[0004]

As shown in FIG. 1, in an electromagnetic shield structure in which a plurality of shield plates are joined to shield electromagnetic waves, the joint end of the shield plate 1 is formed in a substantially U-shaped cross section. Then, the joint end of the shield plate 2 is inserted between the upper plate 5 and the lower plate 7 formed in the same U shape, and the length of the gap 10 generated between the joint end of the shield plate 1 and the joint end of the shield plate 2 is increased. Sa
The electromagnetic wave is shielded by setting the wavelength to about half of the electromagnetic wave to be shielded.

[0005]

According to the present invention, the shield plate 1 and the shield plate 2 are joined together by the structure described above.
The length of the void 10 generated on the joint surface of
By setting the wavelength of the electromagnetic wave to be shielded to about 1/2, the impedance of the air gap 10 seen from the inside of the shield can be made infinite, so that the electromagnetic wave inside the shield is prevented from leaking to the outside, and similarly. Since the impedance of the air gap 10 seen from the outside of the shield can be made infinite, it is possible to prevent intrusion of electromagnetic waves having the same wavelength as the above wavelength from the outside.

[0006]

1 is a perspective view of an electromagnetic shielding structure showing an embodiment of the present invention, and FIG. 2 is a vertical cross section of FIG. Three
Is a dielectric plate, and a microstrip line 4 is provided on the dielectric plate 3, and the microstrip line 4 transmits microwaves. Reference numerals 1 and 2 denote shield plates, which are joined to each other to shield the microwave from leaking to the outside. The joint end of the shield plate 1 is formed such that the upper plate 5, the lower plate 7, and the side plate 6 are provided so that the cross section has a substantially U-shape. The side plate 8 is bent to form a step between the side plate 8 and the joining piece 9 at the tip so that the inner walls of the shield plate 1 and the shield plate 2 in the case of joining are substantially flat. The joining end of the shield plate 2 is inserted between the upper plate 5 and the lower plate 7 which are formed in a shape to join them.

The length of the void 10 formed between the joint end of the shield plate 1 and the joint end of the shield plate 2 when viewed from the cross-sectional direction (A
(Length from point to point B) is about 1 of the wavelength of the electromagnetic wave to be shielded
Since the impedance of the air gap 10 seen from the inside of the shield can be made infinite, microwaves inside the shield are prevented from leaking to the outside, and similarly, the impedance of the air gap 10 seen from the outside of the shield is reduced. Since the impedance can be made infinite, it is possible to prevent microwaves having the same wavelength as the wavelength from entering from the outside. The width of the void 10 is 1 / the wavelength of the microwave to be shielded.
It is set to 2 or less and narrowed so that the joint portion does not become too large. Alternatively, the space 10 may be filled with an adhesive or the like to fix the shield plate 1 and the shield plate 2 together. Therefore, the joint between the shield plate 1 and the shield plate 2 is
There is an effect that microwaves can be shielded without being in direct contact with each other.For example, a shield plate using aluminum die cast and a shield plate using sheet metal, or aluminum die cast with each other, or sheet metal. It is possible to make an electromagnetic shielding structure that is a combination of the above.

FIG. 3 shows another embodiment of the present invention,
It is a vertical cross-section, and in the figure, the same parts as those shown in FIG. 2 are indicated by the same symbols. The difference from the embodiment of FIG. 2 is that
This is the point where the joints between the inner walls of the shield plate 12 and the shield plate 13 are joined together in a protruding state. Similar to the embodiment of FIG. 2, the joining end of the shield plate 12 is formed so that the upper plate 14, the lower plate 15 and the side plate 16 are provided so that the cross section has a substantially U-shape, and the side plate 16 has a substantially central position. The flat plate portion of the shield plate 12 is joined to the portion. One end of the flat plate of the shield plate 13 is used as a joining end, and the joining end of the shield plate 13 is inserted between the upper plate 14 and the lower plate 15 formed in a U-shape so as to be joined to the joining end of the shield plate 12. The length (the length from the point A to the point B) of the gap 17 generated between the joint ends of the shield plate 13 as viewed in the cross-sectional direction is set to about ½ of the wavelength of the electromagnetic wave to be shielded.

[0009]

As described above, according to the present invention,
It is possible to prevent electromagnetic waves from leaking from the joint even if a plurality of shield plates are joined, by making the length of the air gap generated at the joint between the shield plates approximately half the wavelength of the electromagnetic wave that shields them. Unlike the conventional method of mechanically fitting the joint portion, the method of attaching the copper foil tape, or the joining method by solder, the material used as the shield plate is not limited, and the shield plate is not shielded. It is possible to provide an electromagnetic shielding structure capable of effectively shielding electromagnetic waves without any trouble.

[Brief description of drawings]

FIG. 1 is a perspective view of an electromagnetic shield structure showing an embodiment of the present invention.

FIG. 2 is a vertical cross section of the same.

FIG. 3 is a vertical section showing another embodiment of the present invention.

[Explanation of symbols] 1 shield plate 2 shield plate 3 dielectric plate 4 microstrip line 5 upper plate 6 side plate 7 lower plate 8 side plate 9 joining piece 10 void 11 ground conductor 12 shield plate 13 shield plate 14 upper plate 15 lower plate 16 Side plate 17 void

Claims (1)

[Claims] 1. In an electromagnetic shielding structure in which a plurality of shield plates are joined to shield electromagnetic waves, the joint end of the first shield plate is formed in a substantially U-shaped cross section, Insert the joining end of the second shield plate between the plate and the lower plate, and
An electromagnetic shield structure characterized in that the length of a gap generated between the joint end of the shield plate and the joint end of the second shield plate is set to about 1/2 of the wavelength of the electromagnetic wave to be shielded.