JP2000340982A - Electromagnetic wave resonance suppression method in electromagnetic wave advanced shield room - Google Patents

Abstract

(57) [Problem] To provide a practical electromagnetic wave resonance suppression method for an electromagnetic wave advanced shield room and an electromagnetic wave advanced shield room which suppresses electromagnetic wave resonance, which can be applied even when a strong magnetic field source is present. SOLUTION: An electromagnetic wave advanced shielding room having an electromagnetic wave shielding performance of at least 15 dB or more has a frequency band 1.
A method for suppressing electromagnetic wave resonance in an advanced electromagnetic wave shielding room, comprising providing a film or board containing a material having a magnetic loss at 0 to 1000 MHz in an inorganic or organic binder in an amount of 10 to 90% by weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for suppressing electromagnetic wave resonance in an electromagnetic wave shielding room and an electromagnetic wave shielding room in which electromagnetic wave resonance is suppressed.

[0002]

2. Description of the Related Art Electromagnetic wave shielding chambers are used to reduce the passage of electromagnetic waves by partitions or walls using conductors such as metal, to surround noise sources and to suppress the emission of electromagnetic interference, or
It is installed to suppress the entry of electromagnetic waves from the outside and prevent interference with internal equipment.

For example, in a measurement equipment room for measuring a weak magnetic field, such as a brain magnetic field measurement room called SQUID, an electromagnetic wave advanced shield is often installed in order to eliminate the influence of an external fluctuating magnetic field. In addition, since a strong magnetic field is generated in an NMR measurement room or an MRI measurement room, it is required that the entire room be highly magnetically shielded.

[0004] Incidentally, a shielded space generally has a unique cavity resonance frequency determined by the width, length and height of the space. If an electromagnetic wave having a frequency equal to the natural resonance frequency of the shielded room is generated inside the room or injected from the outside, the electromagnetic wave of that frequency may become a standing wave in the shielded room. Such a standing wave is conventionally known as a cause of a phenomenon called a quiet zone where a uniform electric field cannot be secured when performing an electromagnetic field test in a shielded space.

[0005] On the other hand, even if the room is highly shielded against electromagnetic waves, there are always small gaps, such as seams of wall materials, ducts, doors, and the like, when viewed from the electromagnetic waves. Therefore, in the past, in the construction of the shield room, the main focus has been on eliminating as little as possible the slight gaps seen from the electromagnetic waves, and the construction has been devised with respect to the joints of the wall material, the gaps between the ducts and the doors. Such construction has ensured the required performance for shielding electromagnetic waves of relatively low energy.

[0006] However, perfect shielding performance is virtually impossible. Therefore, if the energy of the electromagnetic wave having a frequency equal to the resonance frequency is accumulated in the shielded space, a phenomenon that the electromagnetic wave leaks to the outside from a small gap seen from the electromagnetic wave may occur. Therefore, cavity resonance in the shielded space may cause a reduction in shield performance, and at the same time, may cause a reduction in measurement accuracy of a precision measurement device that handles minute signals, a situation in which measurement is not possible, and the like. However, since this phenomenon is actually recognized only in the case of measurement using a frequency region equal to or near the resonance frequency of the shielded space, it has been conventionally considered to be a problem in shield construction. Did not.

In order to suppress cavity resonance, for example, it is conceivable to use a pyramid-shaped radio wave absorber in which a foaming resin such as urethane is impregnated with a conductive material such as carbon. However, since the height of the pyramid is required to be about half a wavelength, it is required to be several meters to several tens of centimeters, which is not practical. In some cases, a ferrite sintered body is used as an electromagnetic wave absorbing material. However, at present, ferrite sintered bodies can only be used inside electronic equipment and as electronic components, and there are special ferrite sintered body absorbers for anechoic chambers. Can not be used.

[0008] In particular, the MRI measurement room, which has been spreading in recent years,
In a shielded electromagnetic field space such as an NMR measurement room, there is a superconducting magnetic coil that generates strong magnetism, so that the magnetic permeability of a ferrite sintered body or the like is very large (generally, the relative magnetic permeability is 1000 or more). If the body is used for the purpose of suppressing the cavity resonance, the strong magnetic field generated by the superconducting coil may cause the superconducting coil to be forcibly attracted, and may cause an accident such as breakage of the measurement system. Further, it is extremely difficult to separate an object once attracted to the superconducting magnetic coil as long as the superconducting magnetic coil is operating. In order to prevent such a situation, a ferrite sintered body or the like cannot be used. As described above, there is no effective measure in the construction of the shield room for the reduction of the shield performance due to the cavity resonance.

Therefore, a practically advantageous method capable of suppressing electromagnetic wave resonance which lowers the shielding performance of an electromagnetic wave advanced shield room, particularly a method applicable to an advanced shield room in which a superconducting magnetic coil or the like is installed has been desired. Have been.

[0010]

SUMMARY OF THE INVENTION In view of the above-mentioned situation, the present invention provides a practical method for suppressing electromagnetic wave resonance in an electromagnetically shielded room, which can be applied even in the presence of a strong magnetic field source. It is an object of the present invention to provide a shielded electromagnetic wave altitude room.

[0011]

SUMMARY OF THE INVENTION The present invention provides at least one
An electromagnetic wave comprising providing a film or board containing a material having magnetic loss in a frequency band of 10 to 1000 MHz in an inorganic or organic binder in an amount of 10 to 90% by weight in an electromagnetic wave shielding chamber having an electromagnetic wave shielding performance of 5 dB or more. This is a method for suppressing electromagnetic wave resonance in an advanced shield room.

According to the present invention, there is further provided a precision measuring device having an electromagnetic wave shielding performance of at least 15 dB or more, a frequency of an inherent electromagnetic wave resonance mode belonging to a frequency band of 10 to 1000 MHz, and using a superconducting coil. In the electromagnetic wave altitude shield room, frequency band 10 to 10
This is also a method of suppressing electromagnetic wave resonance in an electromagnetic wave advanced shield room in which a film or board containing a material having a magnetic loss at 1000 MHz in an inorganic or organic binder in an amount of 10 to 90% by weight is provided.

The present invention further provides an electromagnetic wave shielding performance of at least 15 dB or more and a frequency of an inherent electromagnetic wave resonance mode belongs to a frequency band of 10 to 1000 MHz, and a frequency band of 10 to 1
It is also a non-resonant electromagnetic wave advanced shielding room provided with a film or board containing a material having a magnetic loss at 000 MHz in an inorganic or organic binder in an amount of 10 to 90% by weight. Hereinafter, the present invention will be described in detail. In addition,
The following description exemplifies an embodiment of the present invention, but those skilled in the art can make obvious changes in accordance with the purpose of the present invention, and therefore limit the present invention in any way. is not.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In a film or board used in the present invention, which contains a material having a magnetic loss in a frequency band of 10 to 1000 MHz in an inorganic or organic binder by 10 to 90% by weight,
The material having a magnetic loss in the frequency range of up to 1000 MHz is not particularly limited as long as it has a magnetic loss in the above band, and examples thereof include a metal oxide magnetic material and a metal magnetic material. The shape of the magnetic particles is not particularly limited, and may be, for example, irregular particles, flat particles, flaky particles, or the like, and may be an aspect material having a short diameter and a long diameter. Also, a molded magnetic material such as a ferrite core or a ferrite bead core may be used.

[0015] There are no particular restrictions regarding the metal oxide magnetic material, for example, MnO to _{Fe 2 O 3, ZnO, NiO} ,
MgO, CuO, ferrite combining the Li ₂ O or the like; NiO-MnO-ZnO-Fe 2 O 3, MnO-Z
_{nO-Fe 2 O 3, NiO} -ZnO-Fe 2 spinel ferrite of O ₃ and the like; garnet-type ferrite; spinel (cubic) of gamma-Fe ₂ O _3, be mentioned γ-Fe ₄ O _4, etc. it can. Among these, in the present invention, Li, Mg, Mn, Co, Ni, Cu, Sn, S
It is preferable to use an Fe oxide containing r, Ba, and the like. These may be used alone or in combination of two or more.

The metal magnetic material is not particularly limited.
For example, a magnetic metal simple substance such as Fe, Co, Ni, or the like, or a surface-treated metal magnetic material obtained by subjecting these to a surface treatment such as an oxidation treatment to obtain a stable mode; silicon steel, sendust, supermalloy, permalloy, Magnetic metal alloys such as amorphous metals; Si, B, Al, Co, Ni, Cr, V, S
Examples thereof include an Fe magnetic alloy containing at least one selected from the group consisting of n, Zn, Pb, Mn, Mo, and Ag. Of these, in the present invention, S
i, B, Al, Co, Ni, Cr, V, Sn, Zn, P
Fe magnetic alloy containing at least one selected from the group consisting of b, Mn, Mo and Ag; Fe, Co or N
Preferred is a magnetic metal simple substance i or a surface-treated metal magnetic material which has been subjected to a surface treatment such as an oxidation treatment to make it stable. These may be used alone or in combination of two or more.

In the present invention, among these, to reduce the weight of the obtained electromagnetic wave absorbing material, in order to enhance the microwave absorbing capacity, it is preferable to use a metal oxide magnetic material, for example, the Fe ₂ O ₃ MnO, ZnO, NiO, MgO,
Spinel type ferrite magnetic powder combining CuO, Li ₂ O, etc., Fe magnetic alloy containing Cr and Ni, Ni
-Zn-based ferrite particles, Mn-Mg-Zn-based ferrite magnetic powder, Mn-Zn-based ferrite magnetic powder, and the like can be suitably used.

In the present invention, the particle size of the magnetic particles present in the magnetic powder to be added is not particularly limited, and may be, for example, a small particle having an average particle size of about 10 μm. For example, magnetic particles of 100 μm or more
It may contain 0 to 100% by weight. There is no particular upper limit on the particle diameter of the magnetic particles. It can be used as long as it is within the thickness of the film or board.

For the magnetic powder, for example, a block of a magnetic material such as the above-mentioned metal oxide magnetic material or the above-mentioned metal magnetic material is pulverized using a stamp mill or the like, and is subjected to a dry sieving method, air classification, and wet sieving. It can be obtained by classification by a separation method, mechanical wet classification or the like. The powder obtained as described above usually has a particle size distribution. Particle size 100
In order to confirm that magnetic particles having a particle size of 20 μm or more are contained in the range of 20 to 100% by weight, for example, the particles may be sieved using a sieve having a mesh size of 100 μm or more. Further, magnetic particles having a particle diameter of 100 μm or more may be mixed with fine particles having a particle diameter of 100 μm or less at a predetermined ratio.

The inorganic binder used in the present invention is not particularly limited. For example, gypsum (calcium sulfate), lime, calcium silicate, magnesia cement, Portland cement, alumina cement, Roman cement, acid-resistant cement, fire-resistant cement And a water-curable inorganic binder such as water glass cement. When strength and water resistance are required, Portland cement or alumina cement may be used. Gypsum is preferred when emphasis is placed on weight reduction, workability during installation, and electromagnetic wave absorbing ability.

As the organic binder used in the present invention, a film-forming binder resin and the like can be widely used, for example, epoxy resin, polyvinyl chloride, and the like.
Organic polymer resins such as ethylene-vilni acetate copolymer (EVA), polyacrylic resin, fluorine-containing copolymer, polyamide, polyester, silicone resin, polyurethane resin, synthetic rubber and foamed polystyrene can be mentioned. Moreover, you may use suitably with a flame retardant.

The compounding amount of the inorganic binder or the organic binder and the material having the magnetic loss is such that the material having the magnetic loss is based on the sum of the inorganic binder or the organic binder and the material having the magnetic loss. 1
0 to 90% by weight. If the material having magnetic loss exceeds 90% by weight, the productivity of the board or film is poor,
The bending strength of the obtained product is reduced, so that sufficient physical properties are not exhibited. In addition, the content of the magnetic material increases, and the weight increases. On the other hand, if the material having a magnetic loss is less than 10% by weight, the electromagnetic wave absorbing ability is not sufficient and is not suitable for practical use. In addition, it is preferable that the compounding amount with the material having the above-mentioned magnetic loss is set to an appropriate value within the above-mentioned range as appropriate according to the kind of the binder used. For example, when gypsum or calcium silicate is used as the inorganic binder, 55 to 90 parts by weight of the inorganic binder and materials 45 to 10 having a magnetic loss are used.
The weight of the board can be reduced, and the weight of the obtained board can be reduced. In particular, when the inorganic binder is gypsum,
Even if the amount of the material having the magnetic loss is small, a sufficient electromagnetic wave absorbing ability can be obtained as long as it is within the above range.

The film or board used in the present invention can be manufactured by a known method using the above-mentioned materials. For example, a material having the above magnetic loss is mixed with a binder resin and molded into a film. Or
The material having the magnetic loss may be a film formed by mixing and applying the material having a magnetic loss to a paint resin such as an acrylic resin, an epoxy resin, or a polyurethane resin; Water,
If necessary, add a fibrous conductor, foamable filler, foaming agent, stabilizer, dispersant, water reducing agent, aggregate, etc., mix well with a mixer to make a slurry, then gypsum board After the slurry is spread on the base paper for use and the thickness thereof is adjusted, the slurry may be further sandwiched between gypsum board base papers and heated, and the slurry may be hardened, coagulated and dried to form a board.

The thickness of the board or film is usually
Although it is about 2 to 50 mm, it does not prevent that it is out of this range. Generally, if it is less than 2 mm,
The physical strength as an electromagnetic wave absorbing material is weak, and if it exceeds 50 mm, the weight increases. In addition, when it is outside the above range when used as a building material, mounting workability and fitability are poor. Preferably, it is 3 to 25 mm.

The electromagnetic wave shielding room to be subjected to the method of the present invention is an electromagnetic wave shielding room having an electromagnetic wave shielding performance of at least 15 dB or more. In this specification, a shield room having this shield performance is referred to as an advanced shield room.
When the electromagnetic wave shielding performance is less than 15 dB, the cavity resonance is not always remarkable, and even if the resonance is prevented to prevent the lowering of the shielding performance, the shielding of the electromagnetic wave itself is not sufficiently realized, High shielding performance cannot be achieved. Preferably, the electromagnetic wave shielding performance is 20 dB or more.

Further, such a shielded room usually has a unique resonance frequency determined by the size of the room. This resonance mode is given by the following equation.

[0027]

(Equation 1)

In the formula, α, β and γ represent the width, length and height of the space. A, B and C represent the resonance mode orders. The resonance frequency has a number of resonance modes determined by three integers of A, B, and C in the case of a spatial standing wave. Generally, the lower the resonance mode order, the higher the peak of the resonance spectrum. Therefore, it is effective to effectively suppress the resonance frequency of the fundamental vibration mode having the highest strength to prevent resonance, but higher-order frequencies can be naturally subjected to absorption. In the present invention, the resonance frequency specific to the shield chamber is preferably such that the resonance frequency having the highest intensity is in the range of 10 to 1000 MHz, and the higher-order resonance mode is also in this range. Generally, it is constructed so as to install a measuring device or equipment inside thereof. For example, a room for installing an MRI measuring device, an NMR measuring device, etc., a shield room such as an anechoic chamber, and the shielding performance is deteriorated. Can be said to be within the above range. For example, a shield chamber having a length of 380 cm, a width of 650 cm, and a height of 320 cm has a resonance frequency of 63.9 MHz.

In order to effectively absorb such a standing wave electromagnetic wave having a resonance frequency generated in the shielded chamber, the above-mentioned material having a magnetic loss in a frequency band of 10 to 1000 MHz is mixed in an inorganic or organic binder. ~
It is preferable to install a film or board containing 90% by weight on a wall surface where the electromagnetic field fluctuation becomes large. When the resonance frequency is known, the resonance mode order is known.
The wall surface where the electromagnetic field fluctuation becomes large can also be predicted. if,
If the resonance cannot be predicted, at least the film or the board is used to form a box-shaped electromagnetic wave advanced shielding room.
Installed on at least one of the walls. It is even better if the two sides share one side. This means that, as shown in FIG. 1, three fundamental vibration modes TE ₁₁₀ , TE _110
As can be seen from the state of the magnetic field of ₀₁₁ and TE ₁₀₁ ,
This is because any of the fundamental vibration modes can be handled by installing the film or board on two wall surfaces sharing one side with each other. If the energy source of the resonance electromagnetic wave and the generation source of the resonance electromagnetic wave are known, it is preferable to install the device on the wall closest to the source. In general, such a resonance source may be a microprocessor or the like built in a computer or various devices.

In the present invention, when the above-mentioned film or board is installed on the inner wall surface of the shield room, it is preferable that the installation area is large, and 100% or 100% of the target wall surface.
Install in less than the area. Further, it is preferable to install the shielded chamber so that a large-area conductor surface is not exposed. Therefore, for example, the film or board may be arranged in a striped or checkered pattern. In addition to installation on a wall surface, for example, there may be an installation around an electronic device so as to surround them or on an inner surface of a rack, a shelf, a box, or the like for storing them, or a fixture in a shielded room. In this specification, the term "wall surface" includes not only a wall but also a surface such as a floor and a ceiling constituting a room.

The above-mentioned film or board used in the present invention exhibits magnetic loss even at 10 to 1000 MHz. Therefore, as a wall material in a shielded room, by installing one or two or more
The effect of the transmission absorption loss of the magnetic field can be used. This has a relative permeability of usually 50 or less. Therefore, in particular, even in an environment where a strong magnetic field is generated, such as an MRI measurement room and an NMR measurement room, it is not forcibly attracted to a magnetic field generation site like a ferrite sintered body,
It can be suitably used in a room with magnetic shielding.

In these cases, the mode of use is as follows:
Typically, for example, a plurality of strips or checkered patterns are formed on two or three adjacent faces of the inner wall of a magnetic shield room in which an MRI measuring apparatus is installed, particularly on a face close to a resonance source. The sheets can be placed one on top of the other. Thus, the resonance of the shield chamber is suppressed, the measurement environment is improved, the leakage of the electromagnetic field to the outside is suppressed, or the electromagnetic energy of the resonance frequency that has entered from the outside is absorbed, and the shielding performance is reduced. This can be easily and simply implemented and implemented even when the shield room is constructed or when the existing shield room is repaired.

Therefore, the present invention has an electromagnetic wave shielding performance of at least 15 dB or more, preferably 20 dB or more, and a frequency of an inherent electromagnetic wave resonance mode of 10 to 10 dB.
A material belonging to a frequency band of 1000 MHz and having a magnetic loss in a frequency band of 10 to 1000 MHz is contained in an inorganic or organic binder.
It is also a room for installation of precision measurement equipment using a superconducting coil, in which a resonance-suppressing electromagnetic wave advanced shield room provided with a film or board containing 0 to 90% by weight is provided.

[0034]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 A slurry was obtained by dispersing Ni—Zn ferrite particles having an average particle size of 10 μm in gypsum so that the content of the ferrite particles became 25% by weight. It was poured between sheets of paper and heated to obtain a gypsum board containing ferrite (width 90 cm, height 180 cm, thickness 0.95 cm).

The resonance frequency of the magnetic shield room (63.9M)
(Hz), a decrease in electromagnetic shielding performance was observed. Therefore, by installing the obtained ferrite-containing gypsum board, the resonating electromagnetic waves were absorbed, and the improvement of the electromagnetic shielding performance was verified.

The ferrite-containing gypsum board was installed on two side walls (small wall and large wall) of a magnetic shield (electromagnetic shield) chamber (380 cm long, 650 cm wide, 320 cm high) in which the MRI apparatus was installed. The measurement of the shielding performance was performed by a method according to MIL-STD-285. The measuring equipment used was a spectrum analyzer HP8563E (trade name) (manufactured by Hewlett Packard) as a receiver, and a signal generator HP86 as a transmitter.
57A (trade name) (manufactured by Hewlett-Packard Co.), and antennas are biconical antennas 3104 and 3108
(Trade name) (manufactured by EMCO) were used.

The horizontal polarization shield performance at 63.9 MHz was measured with and without the ferrite-containing gypsum board, and the following results were obtained.

Shielding performance of door portion Shielding performance of window portion Not installed 64.2dB 47.2dB Installed on 50% of two walls 52.5dB Installed on 70% of two walls 58.6dB 100% of two walls 80.2dB 67.5dB

Example 2 Mn-Mg-Zn in which 85% by weight of particles is 250 μm or more
A ferrite-containing gypsum board was prepared by dispersing ferrite-based particles (maximum particle diameter 2.5 mm) in gypsum so that the ferrite particle content was 25% by weight. (Width 100cm, height 1
00 cm, thickness 0.95 cm).

Electromagnetic wave shielding room (length 1000 cm, width 1)
The above ferrite-containing gypsum board was installed in a checkered pattern on a side wall (500 cm, height 300 cm) (installation area ratio of the target wall surface was 50%), and the shielding performance was measured in the same manner as in Example 1. The measurement was performed at the following three frequencies (cavity resonance frequency of the electromagnetic shield room). Cavity resonance mode TE ₁₃₀ 34 MHz TE ₁₁₁ 53 MHz TE ₁₀₃ and TE ₁₁₃ 151 MHz

The horizontal polarization shield performance was measured when the gypsum board containing ferrite was installed and when it was not installed, and the following results were obtained. The unit is dB.

34MHz 53MHz 151MHz Not installed 40.3 41.2 39.5 Installed on the whole wall (short side) 47.5 47.0 45.2 Installed on the whole wall (long side) 51.6 50. 9 49.2 Installation on two walls (short side and long side) 59.2 57.5 54.8

Example 3 An Fe alloy having a composition of Cr and Ni and 55% by weight of the particles
Is 125 μm (confirmed that 55% by weight of the particles sieved through a 125 μm mesh sieve remain on the screen without passing through) by ethylene-vinyl acetate copolymer (EVA)
This compound was kneaded so as to contain 15% by weight of magnetic particles, and this compound was mixed with a compound having a width of 30 cm, a length of 90 cm, and a thickness of 3 mm.
And extruded into a sheet.

When the sheet containing the magnetic particles is stuck to three surfaces (three surfaces sharing one ridge) inside an electromagnetic shield room (300 cm long, 450 cm wide, and 250 cm high) (installation area ratio for target wall surface) 100%), the electromagnetic wave transmitted inside the electromagnetically shielded room was received inside the electromagnetically shielded room, and the intensity thereof was measured to examine the presence or absence of a resonance phenomenon in the electromagnetically shielded room. The measurement was performed in the same manner as in Example 1. However, both the receiver and the transmitter are installed in the electromagnetic shield, the transmitting antenna is located in the center of the electromagnetic shield room (1 m above the floor), and the receiving antenna is moved in the electromagnetic shield room. The maximum reception intensity at the frequency at which the electromagnetic shield chamber resonated) was recorded. The measurement was performed using a spectrum analyzer HP 8595 (trade name) with a tracking generator (manufactured by Hewlett-Packard), a biconical antenna 3104 (trade name) (EM
(Manufactured by CO Co., Ltd.).

The horizontal polarization shield performance was measured when the sheet containing the magnetic particles was installed and when it was not installed, and the following results were obtained. In Table 1, the unit is dB
It is.

[0047]

[Table 1]

Example 4 A ferrite sintered core (a doughnut having a height of 10 mm, an outer diameter of 10 mm and an inner diameter of 4 mm) made of Ni—Zn ferrite was placed in a gypsum so that the ferrite particle content was 25% by weight. A slurry was prepared by dispersing, and the ferrite-containing gypsum board (width 10) was prepared in the same manner as in Example 1.
0 cm, height 100 cm, thickness 1.5 cm).

Electromagnetic wave shielding room (1000 cm long, 1 horizontal)
The above ferrite-containing gypsum board was installed in a checkered pattern on a side wall (500 cm, height 300 cm) (installation area ratio of the target wall surface was 50%), and the shielding performance was measured in the same manner as in Example 1. The measurement was performed at the following three frequencies (cavity resonance frequency of the electromagnetic shield room). Cavity resonance mode TE ₁₃₀ 34 MHz TE ₁₁₁ 53 MHz TE ₁₀₃ and TE ₁₁₃ 151 MHz

The horizontal polarization shield performance was measured when the gypsum board containing ferrite was installed and when it was not installed, and the following results were obtained. The unit is dB.

34MHz 53MHz 151MHz Not installed 40.3 41.2 39.5 Installed on the whole wall (short side surface) 48.1 46.7 47.7 Installed on the whole wall (long side surface) 55.3 59. 2 54.5 Installed on two walls (short side and long side) 66.2 70.5 65.1

[0052]

Since the method of the present invention has the above-described structure, it is installed in a shielded room, particularly in an advanced shielded room where a strong magnetic field source is present, and is operated at 10 to 1000 MHz.
It is possible to absorb a resonance electromagnetic wave in a band, reduce leakage to the outside, and prevent a decrease in shielding performance.
For this reason, it is possible to easily and easily suppress a decrease in the shielding performance in the natural resonance frequency band, which has been difficult in the conventional shield room construction.

[Brief description of the drawings]

FIG. 1 shows three fundamental resonance modes in a shielded chamber.
The figure represented by showing a magnetic field with a dotted line. (A) TE ₁₁₀
Mode, (b) TE ₀₁₁ mode, (c) TE
₁₀₁ mode respectively.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazunori Kanda 19-17 Ikedanakacho, Neyagawa-shi, Osaka F-term in Nippon Paint Co., Ltd. (reference) 2E001 DH01 FA03 FA11 FA14 FA24 GA12 GA23 HA20 HB01 HB02 HB09 JA01 JA02 JA03 5E321 AA42 BB32 BB53 CC16 GG05 GG07 5J020 BD01 BD02 EA02

Claims (6)

[Claims] An electromagnetic wave shielding room having an electromagnetic wave shielding performance of at least 15 dB or more has a frequency band of 1
A film or board comprising a material having a magnetic loss at 0 to 1000 MHz in an inorganic or organic binder in an amount of 10 to 90% by weight,
A method for suppressing electromagnetic wave resonance in an electromagnetic wave advanced shield room. 2. The method according to claim 1, wherein the film or board is installed on at least one of the six walls forming the box-shaped electromagnetic wave shielding chamber. 3. It has an electromagnetic wave shielding performance of at least 15 dB or more, and a frequency of an inherent electromagnetic wave resonance mode belongs to a frequency band of 10 to 1000 MHz, and
A frequency band of 10 to 1000 MHz is set in an electromagnetic wave shielding room where a precision measuring device using a superconducting coil is installed.
3. A method for suppressing electromagnetic wave resonance in an advanced electromagnetic wave shielding room, comprising: providing a film or board comprising a material having magnetic loss in an inorganic or organic binder in an amount of 10 to 90% by weight. 4. It has an electromagnetic wave shielding performance of at least 15 dB or more and a frequency of an inherent electromagnetic wave resonance mode belongs to a frequency band of 10 to 1000 MHz, and
Inside or on the wall, frequency band 10-1000MHz
2. The resonance-suppressed electromagnetic wave advanced shield chamber according to claim 1, further comprising a film or board comprising a material having a magnetic loss in an inorganic or organic binder in an amount of 10 to 90% by weight. 5. The resonance-suppressed electromagnetic wave advanced shield room according to claim 4, wherein the film or board is installed on at least one of six wall surfaces forming the box-shaped electromagnetic wave advanced shield room. 6. The resonance suppression electromagnetic wave advanced shield room according to claim 4, wherein the resonance suppression electromagnetic wave advanced shield room is a room for installing a precision measuring instrument using a superconducting coil.