TWI431181B - Electromagnetic wave shield and electromagnetic wave absorber - Google Patents

Description

Electromagnetic wave shield and electromagnetic wave absorber

The present invention relates to an electromagnetic wave shield and an electromagnetic wave absorber, and particularly relates to incombustibility and simplification of electromagnetic wave shielding work.

In recent years, with the development of communication systems such as mobile phones and wireless LANs, the necessity of enhancing information security has increased, and communication interference must be prevented. As a specific countermeasure, it is used to suppress the intrusion and leakage of electromagnetic waves, and the grounded conductive material is used to surround the indoor wall surface of the building to shield electromagnetic waves.

For example, Patent Document 1 proposes a technique of constructing a building body using concrete in which an electromagnetic wave shield such as a metal mesh and a ferrite is mixed.

[Patent Document 1] Japanese Patent Publication No. 6-99972 (Page 2, Figure 2, and Figure 3)

However, in the above-mentioned case, there is a drawback in that since electromagnetic waves of almost all frequencies are shielded, machines such as mobile phones and the like that perform electromagnetic wave reception and transmission become unusable.

Moreover, in terms of work, it is very troublesome to conduct electromagnetic waves between the shields.

The present invention has been conceived in view of the above problems, and its main object is to shield electromagnetic waves of a specific frequency band and electromagnetic waves of other frequencies while shielding electromagnetic waves between inside and outside a building, and it is easy to work on the work. It can be used even in places where it is required to have non-combustibility.

In order to achieve the above-described object, in the present invention, a non-combustible surface material (planar member) used as a material for interior and exterior decoration of a building is formed as an electromagnetic wave shield, and a frequency selective surface (FSS "Frequency Selective Surface") is formed. It is used as an electromagnetic wave shield on a wall surface indoors or outdoors.

Specifically, in the present invention, the electromagnetic wave shield includes an incombustible surface material and a frequency selective layer, and the frequency selective layer is formed on at least one surface of the incombustible surface material to be selectively shielded from each other. The electromagnetic wave of the frequency band is composed of a plurality of conductive portions. Here, the term "non-combustible" refers to a person who is rated as "non-combustible" according to a non-combustible, quasi-non-combustible, and flame-retardant test prescribed in the Building Standard Law.

Further, in the above configuration, when the incombustible surface material is plural, the frequency selective layer can be disposed between at least a part of the adjacent incombustible surface materials. Further, when the frequency selective layer is disposed between two or more types of incombustible surface materials, that is, when the frequency selective layer is plural, the conductive portions of the respective frequency selective layers can be selectively shielded from the frequency selective layer. The frequency selects the electromagnetic waves of different frequency bands of the conductive portion of the layer.

As an example of the nonflammable surface material mentioned above, a foamed calcium carbonate board is mentioned. Further, when the frequency selective layer is formed on the incombustible surface material, it may be formed directly by printing or the like, or the film may be laminated on the frequency selective layer. Further, when the non-combustible surface material is laminated, the frequency selective layer may be disposed on the side of the film on the non-combustible surface material, or may be disposed on the side opposite to the non-combustible surface material of the film.

Further, each of the conductive portions of the frequency selective layer may have three first element portions and three second element portions, and the first element portion may extend radially from one point, and the second element portion may be in a different position. The corresponding first element portion extends in the intersecting direction and a part of the longitudinal direction is coupled to the tip end of the first element portion.

Further, the frequency selective layer may be directly disposed on the non-combustible surface material, and when the frequency selective layer is supported by the substrate, the frequency selective layer may be disposed indirectly on the non-combustible surface material via the substrate.

Further, the dielectric constant ε of the non-combustible surface material can be in the range of 1 ≦ ε 2 , and in this case, the thickness T of the non-combustible surface material can be made 1 mm ≦ T ≦ 100 mm.

In addition, when the non-combustible surface material is composed of an electromagnetic wave absorber that absorbs electromagnetic waves incident on the non-combustible surface material, the non-combustible surface material can be placed on the electromagnetic wave incident side of the frequency selective layer.

Further, in the electromagnetic wave absorber of the electromagnetic wave shield of the above-described configuration, the frequency selective layer of the electromagnetic wave shield can be provided with a resistive film and a dielectric layer by shielding electromagnetic waves by reflecting electromagnetic waves of at least one frequency band. The film is disposed on the electromagnetic wave incident side of the frequency selective layer to reflect a part of the electromagnetic wave incident and allows the remaining portion to pass therethrough. The dielectric layer is disposed between the frequency selective layer and the resistive film, and the resistive film is disposed on the resistive film. The surface reflected wave of the at least one predetermined frequency band that is reflected and the internal reflected wave of the at least one predetermined frequency band that is reflected by the frequency selective layer are opposite to each other in the resistive film.

According to the present invention, it is possible to prevent the above-mentioned electromagnetic wave leakage work without deteriorating the electromagnetic wave environment of the electromagnetic wave device other than the specific frequency band, and since the surface material itself is incombustible, it is required to be incombustible. Sex places can also be used.

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)

1 is a cross-sectional view showing an overall structure of an electromagnetic wave shielding plate (borad) according to a first embodiment of the present invention. The electromagnetic wave shielding plate has a plate body 1 and a frequency selective layer 2, and the plate body 1 is incombustible. The lightweight plate-shaped foam, the frequency selective layer 2 is provided on one of the faces of the one-plate main body 1 and selectively shields electromagnetic waves of a specific frequency band by a plurality of antennas 4, 4, ... as a conductive portion which are regularly arranged.

The above-mentioned plate main body 1 is a lightweight foamed carbonized product formed by heat-expanding a composition composed of calcium carbonate and talc (aqueous magnesium silicate) as an inorganic base material, a binder resin, a foaming agent, or the like. The thickness of the calcium plate is preferably about 5 to 20 mm, and the density is preferably about 0.05 to 0.2 g/cm ³ (more preferably 0.15 g/cm ³ or less).

Further, in the present embodiment, when the dielectric constant of the panel main body 1 is low and the electromagnetic wave shielding plate is adhered to the wall material of the building and the exterior material 10 such as the ceiling material, the other material 10 is particularly When the dielectric constant is so high that the electromagnetic wave shielding characteristics of the frequency selective layer 2 are deteriorated, the one-plate main body 1 is interposed between the counterpart material 10 and the frequency selective layer 2 to function as an isolation layer (isolation layer). The suppression frequency selection layer 2 is affected by the counterpart material 10 to deteriorate the electromagnetic wave shielding characteristics.

Specifically, the dielectric constant ε is in the range of 1 ≦ ε ≦ 2 . Further, even in this range, the dielectric constant ε is preferably close to "1". Further, the thickness T1 of the plate body 1 is made 1 mm ≦ T1 ≦ 100 mm. Furthermore, if the thickness dimension T1 is less than 1 mm (T1 < 1 mm), the function as an isolation layer will not be obtained, and if the thickness dimension T1 exceeds 100 mm (T1 > 100 mm), an isolation layer worthy of the installation space will not be obtained. effect. The surface lower limit value of the electromagnetic wave shielding characteristic is more preferably 5 mm (5 mm ≦ T1). On the other hand, it is more preferably 30 mm (T1 作为) when the electromagnetic wave shielding plate is installed in a building or the like. 30mm).

Here, an example of a method of manufacturing the plate body 1 will be briefly described in advance, and an inorganic base material, a binder resin, a foaming agent, and the like are placed in a kneader for 5 minutes, and then, for each 40 weight portions. The calcium carbonate was slowly kneaded with 50 parts by weight of an organic solvent (toluene, etc.) for 1 hour. Further, in the pressurized state of kneading, the obtained composition was filled without gap into the mold plus a sealing lid and pressurized with a press. In this state, heating to 170 ° C is heated to gel the above-mentioned binder resin, and the foaming agent is decomposed. After sufficiently gelating and decomposing, the mold was cooled to room temperature under a pressurized state, and the foam was taken out and further expanded to a predetermined size by heating to 150 ° C again under normal pressure. Thereafter, the organic solvent was evaporated to be completely removed by further slowly heating to 100 ° C after being once cooled to room temperature. The plate body 1 of the present embodiment can be obtained by thinning the foam obtained by the above process.

Further, the mixing ratio (weight ratio of calcium carbonate/talc) of the inorganic base material is preferably 50/50 to 95/5, and the average particle diameter is preferably 50 to 300 μm. The adhesive resin may, for example, be a vinyl chloride resin, an EVA resin or an acrylic resin, and is preferably used in the form of a paste resin having an average particle diameter of 10 to 30 μm. In addition, the content is preferably 10 to 100 parts by weight to 100 parts by weight of the inorganic base material. The foaming agent is not particularly limited as long as it generates a gas by heat decomposition, and examples thereof include azodicarbonamide and azobisisobutyronitrile (AIBN) of an organic foaming agent. , dinitrosopen, p-toluenesulfonylhydrazide (THS), benzenesulfonylhydrazide (p, p'-oxybis, benzenesulfonylhydrazide), inorganic foaming agent, soda carbonate, ammonium chloride, and the like. Further, the content is preferably 10 to 120 parts by weight to 100 parts by weight of the inorganic base material.

In the present embodiment, when the frequency selective layer 2 is provided on the panel main body 1, the electromagnetic wave shielding thin layer 3 shown in Fig. 2 is used. The electromagnetic wave shielding thin layer 3 forms a frequency selective layer 2 on the film substrate 3a, and sequentially deposits the adhesive layer 3b and the release liner on the surface of the film substrate 3a opposite to the frequency selective layer 2. The liner 3c is rolled into a cylindrical shape. Further, the required length is cut, and the release liner 3c is peeled off and adhered to the board body 1, so that the frequency selective layer 2 can be provided in the board body 1. Further, the film base material 3a is preferably a polymer film which can be easily formed into a cylindrical shape and has a flexible shape. In particular, the thickness is generally 10 to 500 μm, preferably 30 to 150 μm, more preferably 50 to 120 μm.

Each of the antennas 4, 4, ... has electromagnetic waves that selectively reflect only a specific frequency band. Therefore, the frequency selective layer 2 transmits electromagnetic waves of other frequencies in addition to shielding electromagnetic waves of a specific frequency band. Specifically, each antenna 4 is formed of a conductive material and has conductivity, and the electromagnetic wave reflectance of the electromagnetic wave of the antenna 4 for a specific frequency band is related to the conductivity of the antenna 4. In other words, the higher the conductivity of the antenna 4 (the resistance of the antenna 4 is small), the higher the electromagnetic wave reflectance of the antenna 4. Therefore, by increasing the conductivity of the antenna 4, the electromagnetic wave reflectance of the electromagnetic wave of the antenna 4 to a specific frequency band can be improved. Examples of such a conductive material include aluminum, silver, copper, gold, platinum, iron, carbon rod, black lead, indium oxide (ITO), indium zinc oxide (IZO), a mixture thereof, or an alloy thereof. Preferably, the antenna 13 contains at least one of copper, aluminum, and silver. The reason is that copper, aluminum, and silver are low in electrical resistance and relatively inexpensive.

Further, each of the antennas 4 may be composed of fine particles containing a conductive material such as copper, aluminum or silver, or may be, for example, a conductive paste composed of a powdery conductive material containing a binder. It is applied to the substrate 3a so as to form a predetermined pattern, and then dried. Specifically, the antenna 4 may be produced by drying the paste in a predetermined pattern, for example, in an atmosphere of 100° C. or more and 200° C. or less for 10 minutes or more and 5 hours or less. As such a conductive paste, a powdery conductive material (such as silver) may be dispersed and mixed into the polyester resin. In this case, the content of the conductive material is preferably 40% by weight or more and 40% by weight or less (40% by weight ≦C ≦ 80% by weight), and more preferably, the weight percentage is 50 or more and 70% by weight or less (50% by weight ≦C ≦ 70wt %). Further, if the content of the conductive material is less than 40% by weight (C<40% by weight), the conductivity of the antenna 4 tends to decrease. On the other hand, if the content of the conductive material is more than 80% by weight (C>80% by weight), it tends to be difficult to uniformly disperse and mix into the resin. Further, the antenna 4 may be a conductive film made of a conductive material and an oxidation preventing film covering the conductive film.

Further, the method of forming the antenna 4 is not limited to the above method, and may be formed by another method. For example, a conductive film (such as an aluminum film or a silver film) is formed on the plate body 1 by a film formation method such as a vapor deposition method, a sputtering method, or a chemical vapor deposition method (CVD method), and is formed according to a pattern such as a lithography. The method is patterned to a prescribed shape size. Further, the antenna 4 can be processed, for example, by an etching method, a sputtering method, a vapor deposition method, a chemical vapor deposition method (CVD method), a screen printing method, a pattern pressure bonding method, a mist coating method, or a mosaic method. Come to form. Also, the thickness T of the antenna 4 is preferably 10 μm or more and 20 μm or less (10 μm ≦T ≦ 20 μm). In other words, if the thickness T of the antenna 4 is less than 10 μm, the conductivity of the antenna 4 tends to decrease (T < 10 μm). On the other hand, if the thickness T of the antenna 4 is larger than 20 μm (T > 20 μm), the antenna The plasticity of 4 tends to decrease.

In the present embodiment, the antennas 4, 4, ... are arranged in a matrix as shown in Fig. 3 . These antennas 4, 4, ... are arranged at regular intervals so that adjacent antennas 4, 4 do not contact each other. As shown in the enlarged view of Fig. 4, each antenna 4 has three first element portions 4a, 4a... and three second element portions 4b, 4b, .... The three first element portions 4 a, 4 a ... extend radially from the antenna center C, and are formed linearly at an angle of 120° to each other. Each of the second element portions 4b extends linearly in a direction perpendicular to the corresponding first element portion 4a, and is coupled to the outer end of the first element portion 4a at the center in the longitudinal direction. In the example of the figure, the lengths L1 and L2 of the first and second element portions 4a and 4b are the same as each other (L1=L2), and the width W1 of the first element portion 4a and the width of the second element portion 4b are the same. W2 is also the same as each other (W1=W2).

Further, the first element portion length L1 and the second element portion length L2 may be different from each other (L1 ≠ L2), and in this case, a relational expression satisfying 0 < L2 < 2 × 3 ^1/2 × L1 is satisfied. In other words, if L2 ≧ 2 × 3 ^1/2 × L1, the adjacent second element portions 4b, 4b will come into contact with each other, and the desired electromagnetic wave shielding effect cannot be obtained. Further, the second element portion length L2 is preferably 0.5 times or more and twice or less (0.5 × L1 ≦ L2 ≦ 2 × L1) of the first element portion length L1 from the viewpoint of achieving a high shielding ratio of a specific frequency band, and more preferably It is 0.75 times or more and 2 times or less (0.75 × L1 ≦ L2 ≦ 2 × L1). Further, the widths W1 and W2 of the first and second element portions may be different from each other (W1 to W2). Further, in the present embodiment, the first and second element portions 4a, 4b are perpendicular to each other, but they may be crossed at an angle other than 90 degrees. Further, the joint position of the second element portion 4b with respect to the first element portion 4a may be a position other than the center of the second element portion 4b in the longitudinal direction.

However, the lengths L1 and L2 of the first and second element portions 4a and 4b of the antenna 4 are related to the electromagnetic wave band (specific frequency band) reflected by the antenna 4. Therefore, the length L1 of the first element portion 4a and the length L2 of the second element portion 4b can be appropriately determined in accordance with the electromagnetic wave band to be shielded by the electromagnetic wave shielding plate. For example, when the length L1 of the first element portion 4a and the length L2 of the second element portion 4b are the same (L1=L2), the total length L (L = 3 × L1 + 3 × L2) of the antenna 4 can be increased. Lower the specific frequency band. Further, conversely, the specific frequency band can be increased by shortening the element length L.

Hereinafter, the electromagnetic wave shielding characteristics of the electromagnetic wave shielding plates according to the lengths L1 and L2 of the first and second element portions 4a and 4b will be described in detail. Here, the widths W1 and W2 of the first and second element portions are both 0.7 mm (W1 = W2 = 0.7 mm).

First, when the length L1 of the first element portion 4a and the length L2 of the second element portion 4b are the same (L1=L2), if the length L1 of the first element portion is L1 = 10.6 mm, as shown in Fig. 5 As shown in the characteristic diagram, the transmittance of electromagnetic waves at a frequency near 2.7 GHz will selectively decrease. In other words, among the electromagnetic waves incident on the electromagnetic wave shielding plate, electromagnetic waves of approximately 2.7 GHz are selectively shielded. This is because the antenna 4 of the frequency selective layer 2 of the electromagnetic wave shielding plate selectively reflects electromagnetic waves having a frequency of approximately 2.7 GHz among electromagnetic waves of various frequencies that are incident. Further, the attenuation amount was measured using a network analyzer manufactured by Agilent.

Next, the relationship between the length L1 of the first element portion 4a of the antenna 4 and the frequency of the electromagnetic wave reflected by the antenna 4 is as shown in FIG. From this characteristic diagram, it can be known that the longer the element length L (here, L = 6 × L1), the lower the frequency of the electromagnetic wave reflected by the antenna 4. In other words, the longer the element length L becomes, the longer the wavelength of the electromagnetic wave reflected by the antenna 4 will be. Therefore, as the element length L becomes shorter, the frequency of the electromagnetic wave reflected by the antenna 4 becomes higher (the wavelength becomes shorter). However, the frequency of the reflected electromagnetic wave is not greatly correlated with the respective widths W1, W2 of the first and second element portions 4a, 4b. In other words, the frequency of the reflected electromagnetic wave is mainly determined based on the length L of the element. Therefore, according to the characteristic diagram of the figure, an appropriate element length L can be obtained from the electromagnetic wave band (specific frequency band) to be reflected by the antenna 4. It is understood that, for example, when electromagnetic waves having a frequency of approximately 5 GHz are to be shielded, the length L1 of the first element portion 4a may be L1 ≒ 6 mm.

On the other hand, when the lengths L1 and L2 of the first and second element portions are different from each other (L1 to L2), the length of the second element portion 4b may be changed by fixing the length L1 of the first element portion 4a. L2, in other words, the specific frequency band can be adjusted by changing the ratio (L2/L1) of the length L2 of the second element portion to the length L1 of the first element portion. Specifically, the specific frequency band can be lowered by lengthening the length L2 of the second element portion 4b, and the specific frequency band can be increased by shortening the length L2 of the second element portion 4b.

In other words, for example, when a Y-shaped antenna (see FIG. 12) is formed, the specific frequency band can be adjusted only by changing the length L1 of the first element portion. In the electromagnetic wave shielding plate according to the present embodiment, as described above, the specific frequency band can be adjusted not only by changing the length L1 of the first element portion 4a and the length L2 of the second element portion 4b, but also by changing the second Since the specific frequency band is adjusted by the ratio (L2/L1) between the element portion length L2 and the first element portion length L1, an electromagnetic wave shielding plate having a high degree of freedom in design can be realized.

Therefore, according to the present embodiment, the electromagnetic wave shielding plate includes a plate body 1 made of lightweight foamed calcium carbonate, and a plurality of antennas 4 arranged in a regular arrangement on one surface of the plate body 1. 4, ... to selectively shield the frequency selective layer 2 of the electromagnetic wave of the specific frequency band, and therefore, it is not necessary to arrange the electrical property when the work for shielding the electromagnetic wave to prevent leakage is performed without deteriorating the electromagnetic wave environment of the electromagnetic wave machine other than the specific frequency band. It is grounded, and since the plate body 1 is light and trouble-free, and it is incombustible, it can be used in a place where incombustibility is required.

In addition, in the above-described embodiment, the plate body 1 is made of lightweight foamed calcium carbonate, but the incombustible surface material of the present invention is an inner wall material, a floor material, and a ceiling material which are incombustible. For exterior wall materials, roofing materials, etc., it is possible to have a flat or curved surface element of a planar or curved surface, and it is preferable if it is lightweight. Further, when the plate body 1 is used as the separator, an example of the material may be polytetrachloroethylene, polyethylene, silk, ivory, paper or the like in addition to the above-mentioned calcium carbonate and talc.

(Embodiment 2)

Fig. 7 is a view showing an arrangement of antennas 4, 4, ... of the frequency selective layer 2 of the electromagnetic wave shielding plate according to the second embodiment of the present invention. In the first embodiment, the same portions as those in the first embodiment are denoted by the same reference numerals, and their description will be omitted.

In the present embodiment, as shown in an enlarged view of FIG. 8, each pair of adjacent two antennas 4, 4 forms an antenna group 5a, and the antenna elements 5a are respectively set to one set of second element portions 4b, 4b. They are arranged in parallel with each other in parallel. Further, the adjacent three sets of antenna groups 5a, 5a, ... are arranged such that the corresponding three sets of second element portions 4b, 4b are arranged in parallel with each other to form a quadratic continuous expansion of the hexagonal antenna assembly. 5 (arrangement group). In other words, the antenna assembly 5 is composed of six antennas 4 arranged in a regular hexagonal shape in which the corresponding six sets of second element portions 4b and 4b are parallel to each other, such that Since the antenna assembly 5 has a regular hexagonal shape, it is possible to exhibit a relatively stable electromagnetic wave shielding performance for electromagnetic waves incident at various incident angles.

Further, the six antennas 4 constituting the antenna assembly 5 and the twelve second element portions 4b of the 18 second element portions 4b included in the six antennas 4 are caused to correspond to the six groups of second element portions 4b. 4b is arranged in a state of being close to each other, and the antenna 4 can be arranged at a high density. As a result, the electromagnetic wave reflectance (electromagnetic wave shielding ratio) of electromagnetic waves in a specific frequency band can be further improved, and electromagnetic waves having high electromagnetic shielding rate for electromagnetic waves in a specific frequency band can be realized. Shielding plate.

The smaller the distance X between the opposing second element portions 4b, 4b, the higher the density of the antennas 4, 4, . Specifically, the distance X between the second element portions 4b and 4b is preferably 3.0 mm or less (X≦ 3.0 mm). In other words, if the distance X is larger than 3.0 mm (X>3.0 mm), the electromagnetic shielding ratio tends to decrease. Further, if the distance X is too small, the second element portions 4b and 4b are likely to cause undesired contact between the second element portions 4b and 4b depending on the method of forming the antenna 4. Therefore, it is preferable to suppress the difference between 0.05 mm or more (X ≧ 0.05 mm).

Here, an electromagnetic wave shielding plate having a high frequency selectivity configured as described above will be specifically described with reference to Figs. 9 to 13 .

Fig. 9 is a view showing electromagnetic wave shielding characteristic characteristics of the electromagnetic wave shielding plate of the embodiment. As can be seen from the figure, in the case of the present embodiment, the ratio of the 10 dB frequency width to the integrated frequency F0 [{(F2-F1)/F0} × 100 (%)] is 10.4%, which is extremely small. In other words, the frequency selectivity is very high. On the other hand, as in the modification 1 shown in FIG. 10, when the so-called cross-type antennas 104, 104, ... are formed, the electromagnetic wave shielding characteristics thereof, as shown in FIG. 11, the ratio of the 10 dB frequency width to the integrated frequency is 17.0% (> 10.4%). ) is larger than the case of the present embodiment. Further, in the second modification shown in FIG. 12, in the case of the Y-shaped antennas 204, 204, ... arranged in a matrix, the electromagnetic wave shielding characteristics, as shown in FIG. 13, the ratio of the 10 dB frequency width to the integrated frequency is 33.0% (> 10.4%) is larger than in the case of this embodiment. Furthermore, the integrated frequencies F0 differ from each other in the above three characteristic maps (Fig. 9, Fig. 11, Fig. 13), but since the 10 dB frequency width does not depend on the integrated frequency, there is no particular problem in comparison. Further, the arrangement distance (vertical and lateral distance) of Comparative Example 2 is the same as that of Comparative Example 1.

Therefore, in addition to the same effects as those in the first embodiment, the present embodiment has an advantage that the 10 dB frequency width is narrow (high frequency selectivity), and particularly has an advantage that it is difficult to cause an electromagnetic wave environment of electromagnetic waves other than a specific frequency band. deterioration.

- Experimental example -

The length L1 of the first element portion 4a of each antenna 4 of the frequency selective layer 2 of the electromagnetic wave shielding plate is fixed at L1=12.24 mm, and the length L2 of the second element portion 4b is changed variously to produce five kinds. Electromagnetic wave shielding plate. Further, the width W1 of the first element portion 4a and the width W2 of the second element portion 4b are W1 = W2 = 1.2 mm.

Specifically, five kinds of antennas of Examples 1 to 4 and Comparative Examples were formed by applying a silver paste to the plate body 1 and drying it. In the first embodiment, in the first embodiment, the length L2 of the second element portion is L2 = 24.48 mm (L1: L2 = 1: 2). In the second embodiment, the length L2 of the second element portion is L2 = 15.30 mm (L1: L2 = 1: 1.25). In the third embodiment, the length L2 of the second element portion is L2 = 12.24 mm (L1: L2 = 1:1). In the fourth embodiment, the length L2 of the second element portion is L2 = 9.2 mm (L1: L2 ≒ 1: 0.75). In the fifth embodiment, the length L2 of the second element portion is L2 = 0 mm. That is, "Y-shaped antenna".

The relationship between the frequencies of the above-described Embodiments 1 to 5 and the transmission attenuation amount is shown in the characteristic diagram of Fig. 14 . Further, the relationship between the respective ratios (L2/L1) of the first element portion length L1 and the second element portion length L2 of the first to fifth embodiments and the integration frequency is shown in the characteristic diagram of Fig. 15 .

As can be seen from Fig. 14, in the first to fourth embodiments having the second element portion 4b, the electromagnetic shielding ratio was higher than that of the fifth embodiment. From this result, it can be seen that in the cases of the first to fourth embodiments, electromagnetic waves of a specific frequency band can be shielded with an electromagnetic shielding ratio higher than that of the fifth embodiment. Further, in the cases of the first to fourth embodiments, there is a steeper peak than in the case of the fifth embodiment. In other words, it can be seen that in the cases of the first to fourth embodiments, the frequency selectivity is higher than that in the case of the fifth embodiment, and electromagnetic waves of a specific frequency band are shielded with higher selectivity.

Further, as can be seen from FIG. 15, as the ratio (L2/L1) of the length L1 of the first element portion to the length L2 of the second element portion increases, the integration frequency tends to become smaller. From this, it can be seen that the integration frequency can be adjusted by changing the length L2 of the second element portion 4b.

(Embodiment 3)

Fig. 16 is a view showing an antenna array of the frequency selective layer 2 of the triple electromagnetic wave shielding plate according to the embodiment of the present invention. In the present embodiment, the frequency selective layer 2 has two antennas 4 and 6 of different sizes, and is provided with two shields different from each other. Electromagnetic waves in a frequency band. In addition, the size and shape of the large antenna 4 are substantially the same as those of the antenna 4 of the first embodiment. Therefore, the same portions as those in the first embodiment are denoted by the same reference numerals, and their description will be omitted.

In the present embodiment, the frequency selective layer 2 includes a plurality of large antennas 4, 4, ... and a plurality of small antennas 6, 6, ... which are formed in a matrix and formed in a matrix. These large antennas 4, 4, ... and small antennas 6, 6, ... are arranged at regular intervals without interfering with each other.

The small antenna 6 is a similar shape of the large antenna 4, and is different in size from the large antenna 4. Specifically, as shown in the enlarged view of Fig. 17, the small antenna 6 is the same as the large antenna 4, and has three first element portions 6a, 6a... and three second element portions 6b, 6b, .... The three first element portions 6 a, 6 a, ... extend radially from the antenna center Cs and are linearly at an angle of 120° to each other. Each of the second element portions 6b extends linearly in the direction perpendicular to the corresponding first element portion 6a, and is coupled to the outer end of the first element portion 6a at the center in the longitudinal direction. In the illustrated example, the lengths Ls1 and Ls2 of the first and second element portions 6a, 6b are the same (Ls1 = Ls2), and the width Ws1 of the first element portion 6a and the width of the second element portion 6b are the same. Ws2 is also identical to each other (Ws1=Ws2).

Further, the first element portion length Ls1 and the second element portion length Ls2 may be different from each other (Ls1 ≠ Ls2), and in this case, a relational expression of 0 < Ls2 < 2 × 3 ^1/2 × Ls1 is satisfied. In other words, if Ls ≧ 2 × 3 ^1/2 × Ls1, the adjacent second element portions 6b, 6b will come into contact with each other, and the desired electromagnetic wave shielding effect cannot be achieved. In addition, from the viewpoint of achieving a high shielding ratio of a specific frequency band, the second element portion length Ls2 is preferably 0.5 times or more and twice or less (0.5 × Ls1 ≦ Ls2 ≦ 2 × Ls1) of the first element portion length Ls1. It is desirable to be 0.75 times or more and 2 times or less (0.75 × Ls1 ≦ Ls2 ≦ 2 × Ls1). Further, the widths Ws1 and W2 of the first and second element portions 6a and 6b may be different from each other (Ws1≠Ws2). Further, in the present embodiment, the first and second element portions 6a, 6b are perpendicular to each other, but they may be crossed at an angle other than 90 degrees. Further, the joint position of the second element portion 6b with respect to the first element portion 6a may be a position other than the center of the second element portion 6b in the longitudinal direction.

Further, although the antenna of the frequency selective layer 2 of the present embodiment has only two types of the large antenna 4 and the small antenna 6, the large antenna 4 and the small antenna 6 may be antennas having different shapes or different sizes. For example, in an environment in which electromagnetic waves of three or more frequency bands are used, the frequency selective layer 2 can be configured by three or more types of antennas having different sizes from each other.

The large antenna 4 and the small antenna 6 each have frequency selectivity. Specifically, the large antenna 4 reflects electromagnetic waves in the first frequency band, and the small antenna 6 reflects electromagnetic waves in the second frequency band (>first frequency band) higher than the first frequency band. Therefore, in the electromagnetic wave shielding plate of the present embodiment, electromagnetic waves of both the first frequency band and the second frequency band can be selectively shielded at the same time, and electromagnetic waves of other frequencies can be transmitted.

However, for example, a wireless LAN uses two frequency band electromagnetic waves of a 2.45 GHz bandwidth and a 5.2 GHz bandwidth. In such an environment, it is necessary to have an electromagnetic wave shielding plate that can selectively shield only two frequency bands used. An electromagnetic wave shielding plate that transmits electromagnetic waves of other frequencies (such as radio waves used in mobile phones, radio waves used for television broadcasting, etc.) that are not used for leakage of information, and electromagnetic wave shielding plates of the present embodiment. It is suitable because it selectively shields electromagnetic waves of a specific two frequency bands and transmits electromagnetic waves of other frequencies.

Here, the electromagnetic wave shielding plate configured as described above, that is, the lengths L1 and L2 and the widths W1 and W2 of the first and second element portions 4a and 4b of the large antenna 4 are 11.19 mm (L1=L2, respectively). =11.19 mm) and 0.7 mm (W1=W2=0.7 mm), and the lengths Ls1, Ls2 and widths Ws1, Ws2 of the first and second element portions 6a, 6b of the small antenna 6 are respectively 6.05 mm (Ls1 = Ls2 = Electromagnetic wave shielding characteristics of electromagnetic wave shielding plates of 6.05 mm) and 0.7 mm (Ws1 = Ws2 = 0.7 mm).

Fig. 18 is a view showing the relationship between the electromagnetic wave frequency incident on the electromagnetic wave shielding plate and the transmission attenuation amount when the electromagnetic wave is transmitted through the electromagnetic wave shielding plate. As can be seen from the figure, in the electromagnetic waves incident on the electromagnetic wave shielding plate, electromagnetic waves of two frequency bands, specifically, a radio wave having a bandwidth of 2.45 GHz and a radio wave having a bandwidth of 5.2 GHz are gradually reduced by both of the electromagnetic wave shielding plates. In other words, among the electromagnetic waves incident on the electromagnetic wave shielding plate, two electric waves of a 2.45 GHz bandwidth and a 5.2 GHz bandwidth are selectively shielded by the electromagnetic wave shielding plate. This is because the large antenna 4 and the small antenna 6 of the frequency selective layer 2 selectively reflect electromagnetic waves of two specific frequency bands. Specifically, the large antenna 4 reflects a radio wave of a low first frequency band (2.45 GHz bandwidth), and the small antenna 6 reflects a high frequency band of a second frequency band (5.2 GHz bandwidth).

However, in the case of a Y-shaped antenna, it is difficult to efficiently arrange two kinds of linear antennas of a size corresponding to a wireless LAN at a high density. In other words, as shown in Fig. 19, in the first modification of the present embodiment, if the adjacent six large antennas 204, 204, ... are placed close to each other so that the element portions 204a, 204a are parallel to each other, It is difficult to arrange the small antennas 206, 206, ... so that the element portions 206a, 206a are parallel to each other, and it is difficult to arrange the small antennas 206, 206 close to each other. Therefore, the large antennas 204, 204 can be arranged at a high density. However, the small antennas 206, 206, ... have to have a smaller number of unit areas than the large antennas 204, 204, ..., and it is difficult to arrange them at a high density. Therefore, the shielding ratio of the electromagnetic waves to be shielded by the small antennas 206, 206, ... is considerably lower than that of the large antennas 204, 204, .... In other words, in the case of the Y-shaped antenna, it is difficult to simultaneously arrange the two types of antennas 204 and 206 at a high density. Therefore, it is also difficult to shield complex electromagnetic waves having different frequency bands with the same high degree of shielding.

This is the same as using a cross-type antenna. In other words, as shown in Fig. 20, in the second modification of the present embodiment, if the large antennas 104, 104, ... are arranged close to each other so that the second element portions 104b, 104b are parallel to each other in a matrix, it is said that The small antennas 106, 106, ... are placed close to each other such that the second element portions 106b, 106b are close to each other, and it is difficult to arrange the small antennas 106, 106 close to each other. Therefore, the large antennas 104, 104, ... However, the small antennas 106, 106, ... will have fewer unit areas than the large antennas 104, and it is difficult to arrange them at a high density. However, in the third modification shown in Fig. 21, only the small antennas 106, 106, ... arranged in the lateral direction are arranged such that the second element portions 106b, 106b are arranged in parallel with each other in parallel with each other, and the small antennas 106, 106 are arranged. The density of ... can be slightly increased, but the density of the large antenna 104 in the longitudinal direction is also lowered. Therefore, it is still difficult to arrange the two antennas 104, 106 at a high density at the same time. Further, in this case, electromagnetic waves of a specific frequency incident in the direction in which the large and small antennas 104, 106 are arranged (the horizontal direction in Fig. 21) can be shielded well, but the direction in which the arrangement direction of the antennas 104, 106 is crossed (for example, the vertical direction of the figure) The electromagnetic wave of a specific frequency that is incident, because the large antennas 104 and 104 adjacent in the same direction are separated from each other and the small antennas 106 and 106 are separated from each other, the electromagnetic shielding rate is lowered, and the electromagnetic wave shielding is caused according to the electromagnetic wave incident direction. The rate varies greatly depending on the angle of incidence.

Therefore, according to the present embodiment, when the two types of antennas 4 and 6 that shield the two types of electromagnetic waves having different phases are disposed in the frequency selective layer 2 of the electromagnetic wave shielding plate, the large antennas 4 each have an extension from the antenna center C. The three first element portions 4 a, 4 a ... which are radially, and the three second element portions 4 b which are joined to the outer side of the first element portion 4 a in the direction perpendicular to the corresponding first element portion 4 a 4b, the small antennas 6 each have three first element portions 6a, 6a, ... extending radially from the antenna center Cs, and are perpendicular to the corresponding first element portion 6a. Since the two second element portions 6b, 6b are connected to each other at the outer end of the element portion 6a, the two antennas 4 and 6 can be simultaneously arranged at a high density, and the two electromagnetic shielding ratios can be shielded with the same high electromagnetic shielding ratio. As a result, in the case of a wireless LAN environment using a 2.45 MHz bandwidth and a two-band radio wave using a 5.2 MHz bandwidth, the electromagnetic wave in the frequency band can be controlled without deteriorating the electromagnetic wave environment of a mobile phone such as a mobile phone using other frequency electromagnetic waves. The wireless LAN wave Drain.

(Embodiment 4)

Fig. 22 is a view showing the arrangement of the large antennas 4, 4, ... and the small antennas 6, 6, ... of the frequency selective layer 2 of the electromagnetic wave shielding plate according to the fourth embodiment of the present invention. In the configuration of the large antenna 4 and the small antenna 6, the same portions as those in the third embodiment are denoted by the same reference numerals, and their description will be omitted. In addition, in the same manner as in the second embodiment, the arrangement of the large antennas 4 is a regular hexagonal shape, and the two large antennas 4 and 4 are arranged in a state in which the second element portions 4b and 4b are arranged in parallel with each other. The large antenna group 5a is configured such that the three large antenna groups 5a, 5a, ... which are arranged close to each other in a state in which the corresponding three sets of second element portions 4b, 4b are arranged in parallel with each other constitute one large antenna assembly 5. Further, the adjacent large antenna assemblies 5 are arranged close to each other such that the corresponding second element portions 4b, 4b are parallel to each other, whereby a plurality of large antenna assemblies 5, 5, ... are continuously expanded in two dimensions. .

The small antenna 6 of the present embodiment is also arranged in the same manner as in the case of the large antennas 4, 4, . In other words, the pairs of the two small antennas 6, 6 in which the second element portions 6b, 6b are arranged in parallel with each other are arranged to constitute the small antenna group 7a, and the corresponding three groups of the second element portions are formed. The small antenna groups 7 are formed by the three small antenna groups 7 a, 7 a ... which are disposed close to each other in a state in which they are parallel to each other. However, in each of the large antenna assemblies 5, one small antenna assembly 7 is disposed in a state in which the large antenna assembly 5 is separated from the other small antenna assemblies 7, 7, .... To be sure, a small antenna assembly 7 is disposed in each of the large antenna assemblies 5 and the portions surrounded by the adjacent three large antenna assemblies 5, 5, .

In the same manner as in the case of the large antenna 4, the smaller the distance between the opposing second element portions 6b, 6b and the small antenna 6 are disposed at a high density, the electromagnetic wave reflectance of the small antenna 6 is increased. Specifically, as shown in FIG. 23, the distance Xs between the opposing second element portions 6b and 6b is preferably 3.0 mm or less (Xs ≦ 3.0 mm), and more preferably 1.0 mm or less (Xs ≦ 1.0 mm). . In other words, if the distance Xs is larger than 3.0 mm (Xs>3.0 mm), the electromagnetic shielding ratio will drop too much. Further, if the distance Xs is too small, the second element portions 6b and 6b are likely to have an unintended contact with each other depending on the method of forming the small antennas 6, 6, ..., and therefore it is preferable to suppress it to 0.4 mm or more ( Xs ≧ 0.4mm), it is safer to suppress it above 0.6mm (Xs ≧ 0.6mm).

Further, when the large small antenna 6 is disposed without shortening the length L2 of the second element portion of the large antenna 4, the large antenna assembly 5 (six hexagonal hexagons) may be arranged as shown in the modification shown in FIG. The small antenna aggregates 7 in the large antennas 4, 4, ...) (six small antennas 6, 6, ... arranged in a hexagonal shape) are relatively rotated around the hexagonal center of the large antenna assembly by a moving angle θ ( For example, θ = 10°). Thereby, the second element portion 4b of the large antenna 4 and the second element portion 6b of the small antenna 6 can be prevented from interfering with each other.

Therefore, according to the present embodiment, the frequency selective layer 2 of the electromagnetic wave shielding plate has two types of electromagnetic waves having different shielding wavelengths, and the two antennas 4 and 6 are arranged so that the large antennas 4, 4, ... are arranged in the second element portion 4b. 4b is formed in parallel with each other to form a large hexagonal antenna assembly 5, and six small antennas 6, 6, ... are arranged in the inner side of each large antenna assembly 5 as the second element portion 6b. Since the 6bs are parallel to each other to form a small hexagonal small antenna assembly 7, the large antennas 4, 4, ... and the small antennas 6, 6, ... can be arranged at a high density at the same time. The electromagnetic shielding rate of the above two types of electromagnetic waves.

Further, in the above-described embodiment, the large antenna assembly 5 and the small antenna assembly 7 are arranged in the closest arrangement, and the antennas can be appropriately adjusted without being closely arranged depending on the required electromagnetic shielding ratio. The number of aggregates 5, 7.

(Embodiment 5)

Fig. 25 is a view schematically showing a cross section of an electromagnetic wave shielding plate according to a fifth embodiment of the present invention.

In the present embodiment, the frequency selective layer 2 is provided on the plate main body 1 by using the electromagnetic wave shielding thin layer 3, which is the same as in the first embodiment. However, the position of the frequency selective layer 2 on the plate main body 1 is different, and this is because of this. The structure of the electromagnetic wave shielding thin layer 3 for setting the frequency selective layer 2 is also different.

In other words, in the first embodiment, the frequency selective layer 2 is located on the opposite side (the upper side in Fig. 1) from the panel body 1. On the other hand, in the present embodiment, the frequency selective layer 2 is located on one side of the panel body 1 ( Figure 25 lower side). In other words, the electromagnetic wave shielding thin layer 3 of the present embodiment is different from that of the first embodiment, and the frequency selective layer 2 is disposed on the same side as the adhesive layer 3b of the film substrate 3a and the release liner 3c. On the frequency selective layer 2, the adhesive layer 3b and the release liner 3c are sequentially laminated.

The frequency selective layer 2 can selectively reflect electromagnetic waves of a specific frequency band even on the side of the panel body 1 as in the present embodiment. However, in the case where the antenna 4 faces the atmosphere as in the first embodiment, even if the shape and material of the antenna 4 are the same, the electromagnetic wave band (specific frequency band) to be reflected (shielded) by the antenna 4 will be different. Here, the relationship between the first element portion length L1 (1/6 of the element length L) of the antenna 4 of the frequency selective layer 2 of the electromagnetic wave shielding plate configured as described above and the adjustment frequency is shown in FIG. According to the figure, in comparison with the case of the first embodiment (see FIG. 6), it can be seen that when the frequency selective layer 2 is covered by the panel body 1, the frequency is selected to face the atmosphere, and the frequency is selected. The electromagnetic wave band that is selected (reflected) by layer 2 will become lower.

(Embodiment 6)

Figure 28 is a cross-sectional view showing the structure of an electromagnetic wave shielding plate according to a sixth embodiment of the present invention.

In the present embodiment, the electromagnetic wave shielding plate includes one layer of the frequency selective layer 2 and two plate bodies 1 having the same function as the isolation layer in the same manner as in the first embodiment. Further, in the two plate main bodies 1, the frequency selective layer 2 is disposed on one surface of one of the plate main bodies 1 by using an electromagnetic wave shielding thin layer (the same electromagnetic wave shielding thin layer as in the first to fourth embodiments). The other plate body 1 is disposed on the surface of the frequency selective layer 2 opposite to the surface on the one side of the one plate body 1.

Specifically, the electromagnetic wave shielding thin layer is provided with an adhesive layer 3b on the side of the frequency selective layer 2, in addition to the adhesive layer 3b on the side opposite to the frequency selective layer 2 of the film substrate 3a, each of which is provided. The body 1 is adhered to the frequency selective layer 2 with the corresponding adhesive layer 3b.

Further, in the case of the present embodiment, the thicknesses T1 and T2 of the two plate bodies 1, 1 may be the same as each other (T1 = T2), or may be different from each other (T1 ≠ T2), for example, in the other material 10 such as a wall material. When the electromagnetic wave shielding plate is laminated and used, the greater the influence of the dielectric constant of the counterpart material 10 on the shielding characteristics of the frequency selective layer 2, the side to which the counterpart 10 is connected (Fig. 28) The thickness dimension T1 of the plate body 1 of the lower side is set to a practical degree capable of suppressing the influence. Further, when other opposing materials such as a face plate, a wallpaper, or a protective material are laminated on the electromagnetic wave shielding plate, when the dielectric constant of the opposing material 20 affects the shielding characteristics of the frequency selective layer 2, it is preferable. The thickness T2 of the plate body 1 on the side (upper side in FIG. 28) joined to the counterpart 20 is set to a practical degree in which the influence can be suppressed. The other configurations are substantially the same as those of the first to fifth embodiments, and the description thereof is omitted.

Therefore, according to the present embodiment, the same effects as those in the first embodiment can be exhibited.

Further, in the above-described embodiment, the two plate bodies 1, 1 are simply laminated in a manufacturing manner. However, the plate main body 1 may be three or more, and as shown in the modification shown in Fig. 29, The frequency selective layer 2 has a plurality of layers (in the illustrated example, there are two layers of frequency selective layers 2, 2 for three plate bodies 1, 1, ...). In this case, among the three plate bodies 1, 1, ..., the thickness dimension T2 of the plate body 1 between the two frequency selective layers 2, 2 is preferably such that the frequency selective layers 2, 2 interfere with each other. The change in the shielding characteristics is suppressed to the extent of practicality. According to this modification, when the frequency selective layers 2, 2, ... of the plurality of layers shield electromagnetic waves of the same frequency band from each other, the shielding rate of the electromagnetic waves can be increased, and when electromagnetic waves of mutually different frequency bands are shielded, It is easy to correspond to an increase in the type of frequency band to be shielded. Further, even in this case, the thickness dimensions T1, T2, and T3 of the respective plate bodies 1, 1, may be identical to each other among the three plate bodies 1, 1, ... (T1 = T2 = T3), They may be different from each other (T1≠T2≠T3), and further, any two of the three plate bodies 1, 1, ... may be identical to each other (T1=T2≠T3, T1≠T2) =T3, T3=T1≠T2).

(Embodiment 7)

Figure 30 is a cross-sectional view showing the structure of an electromagnetic wave shielding plate according to a seventh embodiment of the present invention. In the present embodiment, unlike the first to sixth embodiments, the frequency selective layer 2 (actually one or more types of antennas) is directly formed on the board body 1 without using an electromagnetic wave shielding thin layer.

As a specific method of forming the frequency selective layer 2 as described above, as an example, a conductive paste containing a powdery conductive material such as copper, aluminum or silver using a binder similar to the case of the first embodiment can be given. In other words, the conductive paste is uniformly applied to the panel body 1 in such a manner as to form a predetermined pattern, and then dried. However, in this case, it is preferable that the thickness dimension T1 of the plate body 1 is substantially set such that the adverse effect of the dielectric constant of the counterpart material laminated to the electromagnetic wave shielding plate to the frequency selective layer 2 is suppressed to The practical level is below. Further, when the surface to which the plate main body 1 is applied is an uneven surface, the uneven surface may be polished to remove the unevenness, and then applied. The other configurations are the same as those in the first to sixth embodiments, and the description thereof will be omitted.

Therefore, according to the present embodiment, the frequency selective layer 2 is provided in the panel body 1, and the same simplicity as in the first to sixth embodiments is not provided. However, in other respects, the effects are substantially the same.

(Embodiment 8)

Fig. 31 is a cross-sectional view showing the entire structure of an electromagnetic wave absorber according to an eighth embodiment of the present invention, and Fig. 32 is a cross-sectional view showing the entire structure of the λ/4 type radio wave absorber of the basic structure.

The electromagnetic wave absorber includes a resistive film 30, a frequency selective layer 2, and an air layer 12; the resistive film 30 reflects a part of the electromagnetic wave incident to allow transmission of the remaining portion of the electromagnetic wave; the frequency selective layer 2 is disposed on the resistive film The electromagnetic wave of 30 is incident on the opposite side (the right side of FIGS. 31 and 32) as an electromagnetic wave reflection layer; the air layer 12 is provided as a dielectric layer which is disposed on the resistance film 30 and the frequency selection layer 2 The surface reflected wave of the predetermined frequency band reflected by the resistive film 30 is such that the internal reflected wave in the predetermined frequency band reflected by the frequency selective layer 2 is reversed in the resistive film 30.

Further, in the present embodiment, the frequency selective layer 2 is shielded from electromagnetic waves by selectively reflecting electromagnetic waves including at least one frequency band of the electromagnetic wave of the predetermined frequency band via the antennas 4, 4, ... as the plurality of conductive portions. It also allows transmission of electromagnetic waves outside the above-mentioned frequency bands.

Specifically, the resistive film 30 is formed, for example, of a conductive film made of an ITO film or the like, for example, a substrate 13 such as a polyethylene (PET) film. Further, the frequency selection layer 2 is formed on the board body 1 as in the case of the first embodiment. In other words, the frequency selective layer 2 and the plate body 1 correspond to the electromagnetic wave shields of the first to seventh embodiments. Further, these base material 13 and the plate body 1 are used to protect the resistive film 30 and the frequency selective layer 2, and are disposed on the opposite side to the air layer 12. Further, between the resistive film 30 and the frequency selective layer 2, a spacer layer 15 for maintaining the thickness D of the air layer 12 constant is disposed. In the present embodiment, the thickness D of the air layer 12 is 1/4 (D = λ / 4) of the electromagnetic wave wavelength λ of the frequency band to be absorbed by the electromagnetic wave absorber, and thus the electromagnetic wave absorber of the present embodiment is generally It is called a λ/4 radio wave absorber.

In the electromagnetic wave absorber constructed as described above, one portion of the electromagnetic wave incident is reflected on the resistive film 30, and the other portion of the electromagnetic wave is transmitted through the resistive film 30 to reach the frequency selective layer 2. Among the electromagnetic waves arriving at the frequency selective layer 2, electromagnetic waves of a predetermined frequency band are reflected by the frequency selective layer 2. Further, electromagnetic waves other than the predetermined frequency band are transmitted through the frequency selective layer 2. Further, when the reflected electromagnetic wave (internal reflected wave) of the predetermined band reaches the resistive film 30, the phase of the internally reflected wave is delayed from the air of the same-band electromagnetic wave (surface reflected wave) reflected on the surface of the resistive film 30. The layer 12 has a thickness twice the distance D, which is a half wavelength ([λ/4] x 2 = λ/2). In other words, in the resistive film 30, the internal reflected wave of the predetermined frequency band is opposite to the reflected wave of the same-band surface. According to this, among the surface reflected waves, the surface reflected wave of the predetermined frequency band is absorbed by the electromagnetic wave absorber.

On the other hand, since the electromagnetic wave other than the predetermined frequency band transmits the frequency selection layer 2, the electromagnetic wave other than the predetermined frequency band, that is, the electromagnetic wave other than the predetermined frequency band is internally reflected together with the electromagnetic wave of the predetermined frequency band. It is shielded, but electromagnetic waves outside the specified frequency band are not shielded.

Therefore, according to the present embodiment, the resistive film 30, the frequency selective layer 2, and the spacer layer 15 are provided with a λ/4 type radio wave absorber that absorbs electromagnetic waves of a predetermined frequency band, and the resistive film 30 allows the electromagnetic wave to be reflected in addition to a part of electromagnetic waves that are incident. The remaining portion is transmissive, and the frequency selective layer 2 is disposed on a side opposite to the electromagnetic wave incident side of the resistive film 30 to reflect electromagnetic waves transmitted through the resistive film 30, and the spacer layer 15 is disposed on the resistive film 30 and the frequency. Between the layers 2, an air layer 12 is formed between the two sides 30, 2 to ensure a thickness D of the electromagnetic wave wavelength λ of the predetermined frequency band; as the frequency selective layer 2, except for the plurality of antennas 4, 4, In addition to the electromagnetic wave of the predetermined frequency band, the electromagnetic wave of the predetermined frequency band is selectively reflected. Therefore, electromagnetic waves other than the predetermined frequency band can be transmitted in the opposite direction to the case where the electromagnetic wave other than the predetermined frequency band is shielded.

In the above-described embodiment, the dielectric layer is formed by the air layer 12 having the thickness D of the 1/4 of the electromagnetic wave wavelength λ of the predetermined frequency band to be absorbed between the resistive film 30 and the frequency selective layer 2, but the dielectric layer is formed. The structure of the dielectric layer can be suitably applied to well-known techniques as needed. Specifically, the electrical length of the dielectric layer between the resistive film 30 and the frequency selective layer 2 (=free space length × ε r ^1/2 . [ε r: relative dielectric constant of the dielectric layer]) In the dielectric layer, a resin layer, a ceramic layer, or the like can be used as appropriate, and in the above embodiment, the frequency selective layer 2 is made to reflect only one frequency band of electromagnetic waves. Reflecting a complex frequency band electromagnetic wave containing the one frequency band.

In the above embodiment, as an example of the support base material 13, a PET film or the like is exemplified as the support resistive film 30. However, a plate main body substantially the same as that of the frequency selective layer 2 may be used.

1. . . Board body (non-combustible surface material)

2. . . Frequency selection layer

3 a. . . Film substrate (film)

4. . . Antenna, large antenna (conducting part)

4 a. . . First component part

4b. . . Second component

6. . . Small antenna (conducting part)

6 a. . . First component part

6b. . . Second component

12. . . Air layer (dielectric layer)

30. . . Resistance film

104. . . Y-shaped antenna, Y-shaped large antenna (conducting part)

106. . . Y-shaped small antenna (conducting part)

204. . . Cross antenna, cross type large antenna (conducting part)

206. . . Small cross antenna (conducting part)

Fig. 1 is a cross-sectional view showing the entire structure of an electromagnetic wave shielding plate according to a first embodiment of the present invention.

Fig. 2 is a view showing an overall view (a) of a cylindrical frequency selective thin layer separately formed from a plate body, and an enlarged sectional view (b) of a pivot portion.

Fig. 3 is a plan view showing an antenna pattern of a frequency selective layer of an electromagnetic wave shielding plate.

Fig. 4 is a plan view showing an antenna enlarged.

Fig. 5 is a characteristic diagram showing the relationship between the frequency and the transmission attenuation amount of the electromagnetic wave shielding plate having the length of the first element portion of 10.6 mm.

Fig. 6 is a characteristic diagram showing the relationship between the length of the first element portion of the antenna and the integration frequency.

Fig. 7 is a view showing an antenna pattern of a frequency selective layer of an electromagnetic wave shielding plate according to a second embodiment of the present invention.

Fig. 8 is a plan view showing an enlarged view of two adjacent antennas.

Fig. 9 is a view showing the relationship between the frequency of the antenna and the amount of transmission attenuation, and Fig. 5 is a view corresponding to Fig. 5.

Fig. 10 is a plan view showing a cross-shaped antenna arranged in a matrix pattern in a first modification of the embodiment.

Fig. 11 is a characteristic diagram showing the relationship between the frequency and the transmission attenuation amount of Modification 1.

Fig. 12 is a plan view showing a pattern in which Y-shaped antennas according to a second modification of the embodiment are arranged in a matrix.

Fig. 13 is a view showing the relationship between the frequency of the second modification and the amount of transmission attenuation, and Fig. 11 is a view corresponding to Fig. 11.

Fig. 14 is a characteristic diagram showing the relationship between the frequency and the transmission attenuation amount in the first to fifth embodiments of the experimental example.

Fig. 15 is a characteristic diagram showing the relationship between the length of the second element portion/the length of the first element portion and the integration frequency in the experimental example.

Fig. 16 is a view showing the two types of antennas in the frequency selective layer of the electromagnetic wave shielding plate according to the third embodiment of the present invention, and Fig. 3 is a view corresponding to Fig. 3.

Fig. 17 is an enlarged view showing a small antenna, and is a view similar to Fig. 4.

Fig. 18 is a graph showing the relationship between the frequency and the transmission attenuation amount when the lengths of the first element portions of the antennas of the two sizes are 11.19 mm and 6.05 mm, respectively.

Fig. 19 is a plan view showing a pattern formed by arranging two types of Y-shaped antennas in the first modification of the first embodiment.

Fig. 20 is a view showing a configuration in which two types of cross-shaped antennas of two sizes are arranged as a modification of the second embodiment, and Fig. 19 is a view corresponding to Fig. 19.

Fig. 21 is a view showing a cross-type antenna of two sizes in the third modification of the embodiment arranged in a different pattern.

Fig. 22 is a view showing the two antenna patterns of the size of the frequency selective layer of the electromagnetic wave shielding plate according to the fourth embodiment of the present invention, and Fig. 2 is a view corresponding to Fig. 2.

Fig. 23 is an enlarged view showing adjacent two small antennas, and Fig. 10 is equivalent.

Fig. 24 is a view showing a modification of the fourth embodiment, and Fig. 22 is a view corresponding to Fig. 22.

Fig. 25 is a view schematically showing the overall configuration of an electromagnetic wave shielding plate according to a fifth embodiment of the present invention, and Fig. 1 is a view corresponding to Fig. 1.

Fig. 26 is a view showing a cylindrical selective frequency selection thin layer formed separately from the plate body.

Fig. 27 is a view showing the relationship between the length of the first element portion and the integration frequency, and Fig. 4 is a view corresponding to Fig. 4.

Fig. 28 is a view schematically showing the overall configuration of an electromagnetic wave shielding plate according to a sixth embodiment of the present invention, and Fig. 1 is a view corresponding to Fig. 1.

Figure 29 is a modification of this embodiment. Figure 1 is a comparable diagram.

Fig. 30 is a view schematically showing the overall configuration of an electromagnetic wave shielding plate according to a seventh embodiment of the present invention, and Fig. 1 is a view corresponding to Fig. 1.

Fig. 31 is a cross-sectional view showing the entire structure of an electromagnetic wave absorber according to an eighth embodiment of the present invention.

Fig. 32 is a cross-sectional view showing the entire structure of the λ/4 type radio wave absorber of the basic structure.

1. . . Board body (non-combustible surface material)

2. . . Frequency selection layer

3 a. . . Film substrate (film)

3b. . . Adhesive layer

4. . . Antenna (conducting part)

Claims (13)

An electromagnetic wave shielding body comprising: a non-combustible surface material; and a frequency selective layer disposed on one surface of the non-combustible surface material, wherein at least one electromagnetic wave is selectively shielded by a plurality of conductive portions; wherein Each of the conductive portions of the frequency selective layer has three first element portions and three second element portions, the first element portions extending radially from one point, and the second element portions each intersecting the corresponding first element portion The direction extends and is coupled to the first element tip at a portion of the longitudinal direction. The electromagnetic wave shield according to claim 1, wherein the frequency selective layer is provided to selectively shield electromagnetic waves in a plurality of frequency bands. An electromagnetic wave shielding body comprising: a plurality of incombustible surface materials combined with each other; and a frequency selective layer disposed between at least one set of adjacent incombustible surface materials, and at least one of a plurality of regularly arranged conductive portions is selected The electromagnetic wave of one frequency band is shielded, wherein each of the conductive portions of the frequency selective layer has three first element portions and three second element portions, the first element portion extending radially from one point, and the second element portion Each of them extends in a direction intersecting the corresponding first element portion and is joined to the first element portion tip end in a part of the longitudinal direction. An electromagnetic wave shield according to the third aspect of the patent application, wherein The frequency selective layers are each disposed between adjacent incombustible face materials of a complex array, and each of the frequency selective layers is configured to selectively shield electromagnetic waves of a plurality of frequency bands. The electromagnetic wave shield according to the first or third aspect of the invention, wherein the non-combustible surface material is a foamed calcium carbonate plate. The electromagnetic wave shield according to the first or third aspect of the invention, wherein the frequency selective layer is directly formed on the incombustible surface material. The electromagnetic wave shield according to the first or third aspect of the invention, wherein the frequency selective layer is formed on a film, and the film is placed on the incombustible surface material by laminating the film on a non-combustible surface material. . The electromagnetic wave shield according to claim 7, wherein the frequency selective layer is disposed on one side of the incombustible surface material of the film. The electromagnetic wave shield according to claim 7, wherein the frequency selective layer is disposed on a side opposite to the nonflammable surface material of the film. The electromagnetic wave shield according to the first or third aspect of the invention, wherein the non-combustible surface material has a dielectric constant ε of 1 ≦ ε ≦ 2 . The electromagnetic wave shield according to claim 10, wherein the non-combustible surface material has a thickness T of 1 mm ≦ T ≦ 100 mm. The electromagnetic wave shielding body according to the first aspect of the invention, wherein the non-combustible surface material is composed of an electromagnetic wave absorber that absorbs electromagnetic waves incident on the incombustible surface material, and is disposed on the electromagnetic wave incident side of the frequency selective layer. . An electromagnetic wave absorber comprising the electromagnetic wave shield according to the first aspect of the invention, wherein the frequency selective layer of the electromagnetic wave shield shields the electromagnetic wave by electromagnetic waves reflecting at least one frequency band; the electromagnetic wave shield includes a resistive film and a dielectric In the layer, the resistive film is disposed on the electromagnetic wave incident side of the frequency selective layer, and reflects a part of the electromagnetic wave incident to allow passage of the remaining electromagnetic wave, and the dielectric layer is disposed in the frequency selective layer and the resistive film. The surface reflected wave of the at least one predetermined frequency band reflected by the resistive film is such that the internal reflected wave of the at least one predetermined frequency band reflected by the frequency selective layer is in an opposite phase to the resistive film.