JPH0634298U - Corrugated metal mesh / graphite synthetic electromagnetic wave shielding sheet - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention is to reduce the weight per unit area of an electromagnetic wave shielding material of a building and to improve the absorption and attenuation characteristics of electromagnetic waves in a wide band frequency. [Structure] This structure is composed of a corrugated metal knitted member 1 of a reticulated mild steel sheet and a graphite member 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electromagnetic wave shielding material.

[0002]

[Prior art]

 Conventionally, a ferrite plate, a metal plate, a synthetic resin plate mixed with a ferrite powder, a graphite powder, a metal powder, or the like, or a rubber plate is often used as a material for blocking electromagnetic waves. However, although a ferrite plate absorbs electromagnetic waves in a wide band, it has a large weight per unit area, and a thin plate (about 5 mm thick or less) may be damaged during operation. The metal plate reflects electromagnetic waves in a wide band, but its absorption is very small, so that it has a drawback that it does not block electromagnetic waves depending on the purpose of use. In addition, synthetic resin plates and rubber plates mixed with ferrite powder, graphite powder, metal powder, etc., affect absorption of electromagnetic waves or reflection and bandwidth depending on the mixing ratio, and become brittle when the mixing ratio increases. There is a property that becomes. In addition, if a large amount of ferrite powder is mixed in the rubber plate, the weight per unit area of the rubber itself increases, but the weight further increases.

[0003]

[Problems to be solved by the device]

 Therefore, it is to improve the absorption and blocking characteristics of broadband electromagnetic waves and reduce the weight per unit area of the electromagnetic wave blocking material.

[0004]

[Means for Solving the Problems]

 That is, the graphite members were glued and fired on both sides of the corrugated metal mesh member in which the mesh-shaped mild steel metal sheet material was corrugated.

[0005]

[Action]

 Therefore, by adopting the corrugated metal net material as the mesh-shaped mild steel metal sheet material, the weight per unit area is reduced compared to the ferrite plate material and the metal plate material, and the incident electromagnetic wave that has penetrated the graphite member. The incident electromagnetic wave is attenuated by repeating the irregular reflection absorption of. Further, the graphite member absorbs the incident electromagnetic wave and the diffusely reflected electromagnetic wave from the corrugated metal net member.

[0006]

[Implementation]

 An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing an embodiment of a corrugated metal net / graphite member 2 constituting a corrugated metal net / graphite composite electromagnetic wave shielding sheet 10 according to the present invention. FIG. 2 is an explanatory view of electromagnetic wave absorption and blocking characteristics of the corrugated metal net / graphite composite electromagnetic wave blocking sheet 10 according to the present invention. FIG. 3 shows an example of measurement for measuring the electromagnetic wave absorption blocking attenuation of the corrugated metal mesh / graphite composite electromagnetic wave blocking sheet 10 according to the present invention. FIG. 4 shows the electromagnetic wave attenuation characteristics of the corrugated metal mesh / graphite composite electromagnetic wave shielding sheet 10 according to the present invention. FIG. 5 is a view showing an embodiment in which the corrugated metal mesh / graphite composite electromagnetic wave shielding sheet 10 according to the present invention is applied to a building 20.

In these figures, the corrugated metal mesh / graphite composite electromagnetic wave shielding sheet 10 according to one embodiment of the present invention is a wave-shaped mild steel metal sheet as shown in FIG. The incident wave is repeatedly reflected and absorbed by the corrugated metal mesh member 1 and is absorbed by the graphite member 2, so that the incident electromagnetic wave is greatly attenuated.

That is, the attenuation S in the plane electromagnetic wave incident on the building is obtained by the following equation. S = 20 · log (Ei / Er) dB ... (1) Ei: incident wave electric field strength, Er: transmitted wave electric field strength Further, the attenuation degree S is the spatial impedance Z1 of the incident wave and the corrugated metal sheet 1. And the impedance Z2 consisting of the graphite material 2 and the attenuation S can be obtained from the following equation. S = A + R (dB) ... (2) t: thickness of shielding material, f: frequency, u: relative permeability, g: specific conductivity R: reflection value of shielding material, R = 168 + 10 · log (d / u · f) dB d: specific conductivity, u : Relative permeability, f: frequency

Next, the specific conductivity of the mild steel metal mesh material used in the corrugated metal mesh member 1 made of the mesh-shaped mild steel sheet according to one embodiment of the present invention, the other metal mesh material and the graphite material of the graphite member 2. A comparative example of the magnetic permeability and the relative magnetic permeability is shown below. Specific conductivity Permeability Copper metal net 1 1 Mild steel metal net 0.1 1000 Aluminum metal net 0.662 1 Graphite material <0.1 1 The skin permeability of the corrugated metal net member 1 depends on the thickness and the frequency. However, the values are as follows at frequencies of 100 KHz to 1000 MHz and do not contribute to the cutoff characteristics. Copper metal net 0.02 --- 0.0004 Mild steel metal net 0.002 --- 0.0001 Aluminum metal net 0.0275-0.00025 Graphite member 2 is different from corrugated metal net member 1 in electromagnetic waves. Is absorbed inside and converted to heat. Therefore, from the above calculation formula (2), by using the mild steel metal mesh material for the corrugated metal mesh member 1, the absorption value A of the shielding material becomes superior to other metal mesh materials.

A corrugated metal mesh / graphite composite electromagnetic wave shielding sheet 10 composed of a corrugated metal mesh member 1 and a graphite member 2 is provided at the center of a measurement metal box 11, and a frequency signal transmitter 12 is used to measure the metal box 11 for measurement. The measurement frequency voltage is sent to the coil 13 installed inside the, and the measurement frequency voltage received by the receiving coil 14 is measured by the spectrum analyzer 15 for the attenuation of the electromagnetic wave. Before measuring the attenuation of the electromagnetic wave, Except for the corrugated metal mesh / graphite composite electromagnetic wave shielding sheet 10, the measured frequency voltage from the wave number signal transmitter 12 is measured and set. In addition, the measured frequency voltage when the corrugated metal mesh / graphite composite electromagnetic wave shielding sheet 10 is not inserted and when it is inserted is recorded by the recorder 16.

Next, FIG. 4 shows the electromagnetic wave attenuation characteristics of a frequency of 10 MHz to 1000 MHz by the above measuring method.

FIG. 5 shows an embodiment in which the corrugated metal mesh / graphite composite electromagnetic wave shielding sheet 10 made of a mesh-shaped mild steel metal sheet according to the present invention is applied to the inside of the outer wall 21 of the building 20. By using the corrugated metal mesh / graphite composite electromagnetic wave shielding sheet 10 of the present invention, the weight per unit area becomes lighter than the conventional ferrite plate material and metal plate material. Further, by this implementation, the electromagnetic waves are absorbed and blocked so that the electromagnetic waves are not reflected by the steel frames 22 and the like in the building 20 and cause electromagnetic interference.

[0013]

【The invention's effect】

 As described above, the corrugated metal mesh / graphite composite electromagnetic wave shielding sheet according to the present invention has a reduced weight per unit area and can absorb and block electromagnetic waves in a wide band.

[Brief description of drawings]

FIG. 1 is a front perspective view of a corrugated metal mesh / graphite composite electromagnetic wave shielding sheet of the present invention.

FIG. 2 is an explanatory view of electromagnetic wave absorption / shielding characteristics of the corrugated metal mesh / graphite composite electromagnetic wave shielding sheet of the present invention.

FIG. 3 is a diagram showing an example of measurement of electromagnetic wave absorption / blocking attenuation of the corrugated metal mesh / graphite composite electromagnetic wave blocking sheet of the present invention.

FIG. 4 is an electromagnetic wave attenuation characteristic diagram of the corrugated metal mesh / graphite composite electromagnetic wave shielding sheet of the present invention.

FIG. 5 is a diagram of an embodiment of the corrugated metal mesh / graphite composite electromagnetic wave shielding sheet of the present invention

[Explanation of sign]

1-Corrugated metal mesh member 2-Graphite member 10-Corrugated metal mesh / graphite composite electromagnetic wave shielding sheet 11-Measuring metal box 12-Frequency Signal transmitters 13, 14 ... Coil 15 ... Spectrum analyzer 16 ... Recorder 20 ... Building 21 ... Exterior wall 22 ... Steel frame

Claims (1)

[Scope of utility model registration request] 1. A corrugated metal mesh / graphite composite electromagnetic wave shielding sheet obtained by gluing graphite members on both sides of a corrugated metal mesh member in which a corrugated mild steel metal sheet material is corrugated.