JP5613318B2 - Electromagnetic wave shield structure and reinforced concrete partition - Google Patents

Description

  The present invention relates to an electromagnetic wave shielding structure and a reinforced concrete partition provided on a wall or floor constructed of reinforced concrete between two spaces in order to attenuate a propagating electromagnetic wave.

  Conventionally, as disclosed in Patent Documents 1 and 2, a building having an electromagnetic wave shielding function in order to prevent intrusion of unnecessary electromagnetic waves from the outside to the inside of the building and leakage of electromagnetic waves from the inside to the outside of the building Has been built. That is, when electromagnetic waves propagating outside the building enter the room, images on televisions and personal computers may be disturbed, and electronic devices may malfunction. In addition, information may leak due to propagation of electromagnetic waves generated by indoor wireless transmission to the outside of a building.

On the other hand, walls and floors of buildings and the like are mainly constructed of reinforced concrete, but reinforced concrete itself constructed to satisfy only the proof stress required as a structure has a low electromagnetic wave shielding function. In particular, electromagnetic waves having a short wavelength of 1 GHz or more almost pass through the walls of reinforced concrete.
Therefore, for example, a building having an electromagnetic wave shielding function is formed by attaching a member having an electromagnetic wave shielding function such as an iron plate, a metal net, a metal foil, or a metal mesh to the surface of a reinforced concrete wall or floor.

Japanese Patent Laid-Open No. 11-121973 JP 2002-54248 A

  However, the conventional method of attaching the electromagnetic wave shielding member to the wall surface is a method of adding the electromagnetic wave shielding member separately from the structure constructed by the reinforced concrete. Processes such as pasting work increase.

  In addition, there are cases where it is desired to shield only electromagnetic waves of a specific frequency, such as wanting to receive radio waves from a mobile phone even inside a building but not wanting radio LAN (Local Area Network) radio waves to leak outside.

  Therefore, an object of the present invention is to provide an electromagnetic wave shielding structure and a reinforced concrete partition that can exhibit an electromagnetic wave shielding function against electromagnetic waves having a target frequency.

In order to achieve the above object, the electromagnetic wave shielding structure of the present invention is an electromagnetic wave shielding structure for attenuating an electromagnetic wave of a target frequency propagated in a predetermined propagation direction, and has a constant interval in a direction substantially orthogonal to the propagation direction. A main conductor portion formed by a plurality of first conductor rods arranged side by side, and at a position spaced from the main conductor portion in the propagation direction, in substantially the same direction as the first conductor rod. A sub-conductor portion formed by a plurality of first sub-conductor rods arranged side by side at a predetermined interval, and the distance in the propagation direction between the main conductor portion and the sub-conductor portion is Based on a length of an integral multiple of one wavelength (where the integer is a positive integer excluding 0) depending on the medium interposed between the main conductor portion and the sub-conductor portion of the target frequency The first conductor rod is set within an allowable error range. The interval is set within a predetermined allowable error range based on a length of an integer multiple of 3 (where the integer is a positive integer excluding 0) as the interval between the first sub-conductor rods. .
The reinforced concrete partition of the present invention is characterized in that the electromagnetic wave shielding structure is embedded in a concrete portion having the propagation direction as a thickness direction.

The electromagnetic wave shielding structure of the present invention configured as described above includes a main conductor portion formed by a plurality of first conductor rods arranged side by side at a predetermined interval in a direction substantially orthogonal to the propagation direction, A sub-conductor portion formed by a plurality of first sub-conductor rods arranged side by side at a predetermined interval in substantially the same direction as one conductor rod is arranged. Further, the distance between the main conductor portion and the sub conductor portion is adjusted based on the wavelength of the electromagnetic wave of the target frequency. And the space | interval of the 1st subconductor rod of a subconductor part is adjusted to the width | variety which can attenuate the propagation of the electromagnetic wave of an object frequency largely with respect to the space | interval of the 1st conductor rod of a main conductor part.
Thus, the electromagnetic wave shielding function can be exhibited against electromagnetic waves having a target frequency simply by adjusting the interval and positional relationship between the conductor rods and the sub conductor rods. Moreover, the reinforced concrete partition of this invention can shield effectively the electromagnetic wave of object frequency only by burying a subconductor part in the wall and floor of a reinforced concrete necessarily constructed | assembled as a structure.

It is sectional drawing explaining the structure of the reinforced concrete partition of embodiment of this invention. It is a perspective view explaining the composition of the reinforced concrete partition of an embodiment of the invention. It is explanatory drawing which showed the relationship between the lattice spacing of a main conductor part, and the lattice spacing of a subconductor part. It is explanatory drawing which showed typically the model of the analysis performed in order to confirm the electromagnetic wave shielding effect of a reinforced concrete partition. It is an electric field strength distribution map which shows an analysis result. It is the graph which showed the relationship between a frequency and an electromagnetic wave shielding effect with respect to the lattice space | interval of a some subconductor part. It is the graph which showed the relationship between a frequency and an electromagnetic wave shielding effect with respect to the several combination of the lattice spacing of a main conductor part and a subconductor part. It is the graph which showed the relationship between the frequency of the electromagnetic waves which cause resonance in a reinforced concrete partition, and the lattice spacing of the main conductor part. It is the graph which showed the relationship between the reflection wavelength of the electromagnetic waves which cause resonance in a reinforced concrete partition, and the lattice spacing of the main conductor part. It is a perspective view explaining the structure of the main conductor part formed of the conductor rod by which the widened part of Example 1 was extended.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the RC wall 1 as a reinforced concrete partition according to the present embodiment partitions an internal space R1 of the building as one space and an external space R2 of the building as the other space. By providing this RC wall 1, the electromagnetic wave of the target frequency propagating in the propagation direction from the internal space R1 of the building to the external space R2 or from the external space R2 to the internal space R1 is shielded. Here, “shielding” means a state in which an electromagnetic wave shielding effect (SE: Shield Effectiveness) is obtained by attenuating a propagating electromagnetic wave.

First, the configuration of the RC wall 1 will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the RC wall 1 includes a concrete portion 2 having a thickness C, a front rebar lattice 3 as a main conductor portion embedded in the internal space R1 side of the concrete portion 2, and a front rebar lattice. 3 as a rear conductor lattice 4 as a main conductor portion embedded in the external space R2 side in parallel with the sub-conductor portion embedded in a substantially central position between the front reinforcement lattice 3 and the rear reinforcement lattice 4. Welding wire mesh 6. Then, an electromagnetic wave shielding structure is formed by the front reinforcing bar lattice 3, the welded wire mesh 6, and the rear reinforcing bar lattice 4 which are disposed substantially parallel to each other with an interval in the propagation direction.

The concrete part 2 is manufactured by mixing cement, aggregate, and water, for example, and becomes a medium for propagating electromagnetic waves. Moreover, what is necessary is just to set the mixing | blending of the concrete part 2 so that the intensity | strength required as the RC wall 1 may be satisfy | filled.
In addition, a surface of the wall formed by the concrete portion 2 on the inner space R1 side is a front surface 11, and a surface on the outer space R2 side is a rear surface 12. Further, in the concrete portion 2, the propagation direction is the thickness direction, and the front surface 11 and the rear surface 12 are substantially orthogonal to the propagation direction. And as shown in sectional drawing of FIG. 1, the interior board 5 is arranged in parallel with the front surface 11 at intervals from the front surface 11 to internal space R1 direction.

  Further, as shown in FIG. 2, the front reinforcing bar grid 3 is substantially perpendicular to the vertical reinforcing bars 31 as a plurality of first conductor rods erected in the vertical direction and the vertical reinforcing bars 31. Are formed in a lattice shape by a plurality of horizontal reinforcing bars 32,. That is, the vertical reinforcing bars 31,... And the horizontal reinforcing bars 32,... Are arranged side by side with a predetermined interval in a direction substantially orthogonal to the propagation direction. The surface where the vertical reinforcing bars 31,... And the horizontal reinforcing bars 32,. The “rebar” is a main structural member arranged as a tensile resistance member of the RC wall 1.

Further, the horizontal reinforcing bars 32 and 32 and the vertical reinforcing bars 31 and 31 are arranged substantially in parallel at regular intervals, respectively. The distance between the horizontal bars 32 and 32 is defined as a distance P1, and the distance between the vertical bars 31 and 31 is defined as a distance P2. Furthermore, this space | interval P1 (P2) is made equal among all the horizontal reinforcing bars 32 and 32 (vertical reinforcing bars 31, 31). In the following, when the interval P1 and the interval P2 are equal, both may be collectively referred to as the lattice interval P.
Further, as shown in FIG. 1, the diameter of the vertical reinforcing bar 31 is defined as a reinforcing bar diameter B1, and the diameter of the horizontal reinforcing bar 32 is defined as a reinforcing bar diameter B3. Further, the distance between the vertical reinforcing bar 31 and the front surface 11 of the concrete portion 2 is defined as the covering thickness C1. The distance between the front surface 11 and the reinforcing bar surface 30 is D1, and the distance between the reinforcing bar surface 30 and the rear surface 12 is D2.

  On the other hand, the rear reinforcing bar lattice 4 is substantially perpendicular to the vertical reinforcing bars 41 and the vertical reinforcing bars 41 as a plurality of first conductor rods erected in the vertical direction, like the front reinforcing bar lattice 3. It forms in a grid | lattice form with the horizontal reinforcing bars 42 ... as several 2nd conductor rods which cross | intersect. That is, the vertical reinforcing bars 41,... And the horizontal reinforcing bars 42,... Are arranged substantially in parallel with a certain interval in a direction substantially orthogonal to the propagation direction. The surface where the vertical reinforcing bar 41 and the horizontal reinforcing bar 42 are in contact becomes the reinforcing bar surface 40. Moreover, let the space | interval of the thickness direction of the concrete part 2 of the reinforcing bar surface 30 and the reinforcing bar surface 40 of the front side reinforcement lattice 3 be the distance C3.

Further, the distance between the horizontal reinforcing bars 42 and 42 and the distance between the vertical reinforcing bars 41 and 41 are set to the intervals P1 and P2 in the same manner as the front reinforcing bar lattice 3, and between all the horizontal reinforcing bars 42 and 42 (vertical reinforcing bars 41 and 41). It is set to be equal (grating interval P).
Furthermore, as shown in FIG. 1, the diameter of the vertical reinforcing bar 41 is defined as a reinforcing bar diameter B2, and the diameter of the horizontal reinforcing bar 42 is defined as a reinforcing bar diameter B4. Further, the distance between the vertical reinforcing bar 41 and the rear surface 12 of the concrete portion 2 is defined as the covering thickness C2.

  Further, a secondary rebar surface 60 described later formed by the welded wire mesh 6 is embedded in the concrete portion 2 so as to be substantially parallel to the rebar surface 30 of the front rebar lattice 3 and the rebar surface 40 of the rear rebar lattice 4. . The welded wire mesh 6 includes a plurality of second sub-lines that intersect with the vertical wire members 61 so as to be substantially perpendicular to the vertical wire members 61,. It forms in a grid | lattice form with the horizontal wire 62 as a conductor rod. That is, the vertical wires 61,... And the horizontal wires 62,... Are arranged side by side with a certain interval in a direction substantially orthogonal to the propagation direction. And the surface which the vertical wire 61, ... and the horizontal wire 62, ... contact becomes the sub-rebar surface 60. Note that the welded wire mesh 6 is not arranged as a main structural member of the RC wall 1 like the above-described reinforcing bars, but is formed by a reinforcing bar having a small diameter, a steel wire, or the like.

Further, the horizontal wire rods 62 and 62 and the vertical wire rods 61 and 61 are arranged substantially in parallel at regular intervals, respectively. The distance between the horizontal wires 62 and 62 is defined as a distance S1, and the distance between the vertical wires 61 and 61 is defined as a distance S2. Furthermore, this space | interval S1 (S2) is made equal among all the horizontal wire rods 62 and 62 (vertical wire rods 61 and 61). In the following, when the interval S1 and the interval S2 are equal, both may be collectively referred to as a lattice interval S.
Further, as shown in FIG. 1, the diameter of the vertical wire 61 is set as a secondary reinforcing bar diameter E1, and the diameter of the horizontal wire 62 is set as a secondary reinforcing bar diameter E2. Further, the distance between the secondary reinforcing bar surface 60 of the welded wire mesh 6 and the reinforcing bar surface 40 of the rear reinforcing bar lattice 4 is defined as D3.

  As shown in FIGS. 2 and 3, the vertical reinforcing bars 31 and 41 and the vertical wire 61 are directed in substantially the same direction. Moreover, the horizontal reinforcing bars 32 and 42 and the horizontal wire 62 are directed in substantially the same direction. Further, as shown in FIG. 3, the ratio of the lattice interval P of the front reinforcing bar lattice 3 (or the rear reinforcing lattice 4) and the lattice interval S of the welded wire mesh 6 is P: S = 3n: 1 (n is 0). Excluding a positive integer).

Next, the analysis performed in order to examine the electromagnetic wave shielding effect of RC wall 1 of this Embodiment is demonstrated, referring FIG.4 and FIG.5.
FIG. 4 is a diagram schematically showing a part of the analysis model used in the numerical simulation by the finite element method. As shown in FIG. 4, an internal space MR1 and an external space MR2 are modeled on both sides of the modeled RC wall M1. Further, inside the RC wall M1, an L-shaped front reinforcing bar lattice M3 and a rear reinforcing bar lattice M4 that are a quarter of the lattice (lattice spacing P, P) shown in FIG. 3 are modeled. Yes. Further, a welded wire mesh M6 that falls within a quarter of the lattice (lattice spacing P, P) is also modeled. The inner wall R1 side of the RC wall M1 is the front surface M11, and the outer space MR2 side of the RC wall M1 is the rear surface M12.
The reinforcing bar diameter B1-B4 is 10 mm, the secondary reinforcing bar diameters E1, E2 are 3.2 mm, the thickness C of the RC wall M1 is 200 mm, the covering thickness C1 of the front reinforcing bar grid 3 is 40 mm, and the covering thickness of the rear reinforcing bar grid 4 The length C2 was 35 mm, the distance C3 between the reinforcing bar surface 30 and the reinforcing bar surface 40 was 105 mm, and the distance D3 between the secondary reinforcing bar surface 60 and the reinforcing bar surface 40 was 50.9 mm (see FIG. 1).

  In this analysis, a vertically polarized plane wave was propagated from the internal space MR1 side toward the RC wall M1, and the electric field strength of the electromagnetic wave propagated to the external space MR2 side was confirmed. The simulation was performed by changing the frequency of vertically polarized waves in 0.01 GHz increments from 2.0 GHz to 3.0 GHz. Among these analysis results, an example in which the electromagnetic wave shielding effect by the RC wall M1 was high is shown in FIG. 5 as an electric field intensity distribution diagram viewed from the side. In the drawing, a portion having a relatively high electric field strength is indicated by a dark dot, and as the electric field strength decreases, the dot becomes lighter and further becomes white.

  FIG. 5 is an electric field intensity distribution diagram when a vertically polarized plane wave having a frequency of 2.79 GHz is propagated. When an electromagnetic wave of this frequency is propagated, it can be seen that a standing wave is formed between the welded wire mesh M6 and the rear reinforcing bar lattice M4 as shown in FIG. 5, and the electric field strength is high (dark dots). This is probably because resonance occurred between the welded wire mesh M6 and the rear reinforcing bar lattice M4 (distance D3 in FIG. 1), and a standing wave was formed by the mutual relationship of the multiple reflection of the reflected wave. That is, it is considered that the welded wire mesh M6 and the rear reinforcing bar lattice M4 function as a semi-transmissive surface that reflects at least a part of the incident electromagnetic wave. Resonance occurs between these two semi-transmissive surfaces, and a standing wave is formed because the distance between the semi-transmissive surfaces is approximately an integral multiple of one wavelength of the resonating electromagnetic wave. It is done.

On the other hand, the reason why the electric field strength is very low (thin dots or white) in the external space MR2 is considered to be that the electromagnetic waves are attenuated by resonance in the RC wall M1 and hardly transmitted to the external space MR2. .
Thus, it can be seen that the RC wall M1 resonates inside the wall at a specific frequency, and the transmitted wave is suppressed. Here, as a phenomenon contributing to suppression of transmitted waves, a phenomenon other than resonance and resonance can be considered, but since at least resonance occurs, these phenomena are collectively referred to as “a phenomenon corresponding to resonance”.

In FIG. 6, the lattice spacing P of the front reinforcing bar lattice 3 and the lattice spacing P of the rear reinforcing steel lattice 4 are fixed to 150 mm, and the lattice spacing S of the welded wire mesh 6 is changed to 30 mm, 50 mm, 75 mm, and 150 mm. The result of having performed the analysis is shown. For comparison, a case without the welded wire mesh 6 was also analyzed.
In FIG. 6, the frequency is on the horizontal axis and the electromagnetic shielding effect (SE) is on the vertical axis. Here, the electromagnetic wave shielding effect (SE) is expressed in decibels (dB) based on the ratio of the electric field strength compared with or without the RC wall M1.
SE = 20 log ₁₀ (electric field strength when there is no RC wall M1 / electric field strength when there is an RC wall M1)
For example, an electromagnetic wave shielding effect (SE) of 20 dB indicates that the intensity of electromagnetic waves is attenuated to 1/10, and the shielding rate is 90%.

When the graph of FIG. 6 is seen, the peak (23 dB) of the electromagnetic wave shielding effect (SE) is generated at a frequency of 2.8 GHz in a case (two-dot chain line) where the lattice spacing S of the welded wire mesh 6 is 50 mm. This indicates that an effect of attenuating an electromagnetic wave that is about 8 dB larger than the peak (15 dB at a frequency of 2.79 GHz) in the case without the wire mesh 6 (solid line) is obtained.
On the other hand, each case in which the lattice spacing S of the welded wire mesh 6 is 30 mm, 75 mm, and 150 mm can attenuate electromagnetic waves only to the same extent as the case without the welded wire mesh 6. That is, even if the lattice spacing S of the welded wire mesh 6 becomes narrower or widens at the boundary of 50 mm, the effect of attenuating electromagnetic waves as when the lattice spacing S of the welded wire mesh 6 is 50 mm is obtained. I understand that there is no. The lattice spacing S of 50 mm is in the relationship of P: S = 3: 1 with the lattice spacing P = 150 mm of the front reinforcing bar lattice 3 and the rear reinforcing bar lattice 4.

Therefore, the analysis results obtained by setting the ratio of the lattice interval P of the front reinforcing bar lattice 3 and the rear reinforcing lattice 4 and the lattice interval S of the welded wire mesh 6 to P: S = 3: 1 are shown in FIG. It was shown to. That is, in FIG. 7, the grid spacing P is changed in units of 10 mm such as 150 mm, 160 mm, 170 mm, and 180 mm, and the grid spacing S is set to 50 mm, 53 mm, 56 mm, and 60 mm so as to be one third of each. It is the figure which showed the analysis result of the case.
It can be seen from FIG. 7 that a large peak appears in all cases. That is, in the case of P = 150 mm: S = 50 mm (solid line), an electromagnetic wave shielding effect (SE) peak (23 dB) occurs at a frequency of 2.8 GHz. In the case of P = 160 mm: S = 53 mm (one-dot chain line), an electromagnetic wave shielding effect (SE) peak (26.7 dB) occurs at a frequency of 2.6 GHz. Furthermore, in the case of P = 170 mm: S = 56 mm (two-dot chain line), an electromagnetic wave shielding effect (SE) peak (21.4 dB) occurs at a frequency of 2.5 GHz. In the case of P = 180 mm: S = 60 mm (broken line), an electromagnetic wave shielding effect (SE) peak (16.3 dB) occurs at a frequency of 2.36 GHz. Therefore, it can be seen that a large electromagnetic shielding effect (SE) can be obtained by setting the ratio of the lattice spacing P to the lattice spacing S to be P: S = 3: 1.

As can be seen from the analysis results described above, inside the RC wall 1, the welding is performed between the reinforcing bar surface 40 of the rear reinforcing bar lattice 4 and the secondary reinforcing bar surface 60 of the welded wire mesh 6 or the reinforcing bar surface 30 of the front reinforcing bar lattice 3. A phenomenon corresponding to the resonance of the electromagnetic wave occurs between the reinforcing bar surface 60 of the wire mesh 6 or between the reinforcing bar surface 40 of the rear reinforcing bar lattice 4 and the reinforcing bar surface 30 of the front reinforcing bar lattice 3. Energy is lost.
Since the phenomenon according to the resonance generated here occurs not only in the first-order resonance but also in the second-order, third-order,..., N-th order resonance, P: S = 3n: 1 (n Is a positive integer other than 0).
Similarly, the distance between the reinforcing bar surface 40 of the rear reinforcing bar lattice 4 and the secondary reinforcing bar surface 60 of the welded wire mesh 6 or the distance between the reinforcing bar surface 30 of the front reinforcing steel lattice 3 and the auxiliary reinforcing bar surface 60 of the welded metal mesh 6. It can be generalized to n times (one is a positive integer excluding 0) one wavelength (reflection wavelength) λ _c in the concrete of the electromagnetic wave of the target frequency.

FIG. 8 shows a graph in which the lattice interval P is on the horizontal axis and the frequency f at which the electromagnetic wave is reflected (resonated) in the RC wall 1 is on the vertical axis. The frequency graph F1 in FIG. 8 is a plot of analysis results, and the frequency linear graph FL is a graph based on the relational expression obtained by the least square method.
This frequency linear graph FL shows the frequency f and the lattice spacing P when the electromagnetic wave is reflected between the reinforcing bar surface 40 of the rear reinforcing bar lattice 4 or the reinforcing bar surface 30 of the front reinforcing bar lattice 3 and the secondary reinforcing bar surface 60 of the welded wire mesh 6. Shows the relationship. Further, a band FW indicated by dots in FIG. 8 indicates the vicinity of 2.4 GHz which is a frequency often used in a wireless LAN (Local Area Network).

For example, in order to resonate an electromagnetic wave having a frequency of 2.4 GHz, it can be read from the frequency linear graph FL of FIG. 8 that the lattice interval P should be 177 mm (the lattice interval S of the welded wire mesh 6 is 177/3 = 59 mm). . Note that, when using this frequency linear graph FL, an effect of shielding electromagnetic waves around the target frequency can be obtained as long as it is within a predetermined allowable error range. Therefore, the lattice spacing when the RC wall 1 is actually constructed is obtained. P can be changed within an allowable error range (for example, an error within a reinforcing bar diameter or a secondary reinforcing bar diameter).
The reason why the lattice spacing P and the lattice spacing S can be changed within the diameter (rebar diameter or sub-rebar diameter) of the reinforcing bars (31, 32, 41, 42) serving as the conductor bars or the wires (61, 62) serving as the subsidiary conductor bars. This is because the position of the reflection surface of the actual electromagnetic wave becomes the surface of the conductor rod or the sub conductor rod.

On the other hand, FIG. 9 shows the relationship between the frequency f and the grating interval P in FIG. 8 by the relationship between the wavelength λ _c of the electromagnetic wave in the RC wall 1 and the grating interval P. That 9, the vertical axis wavelength lambda _c, has a lattice spacing P in the horizontal axis. Here, the wavelength λ _c of the concrete portion 2 in the RC wall 1 can be calculated by the following conversion equation, where ε _r is the relative dielectric constant of the concrete portion 2 serving as a medium, f is the frequency of the electromagnetic wave, and v is the speed of light.
λ _c = v / f × 1 / √ε _r

When the frequency graph F1 is converted by the above conversion formula, a wavelength graph W1 is obtained. The relational expression of the wavelength linear graph WL obtained by the least square method is as follows.
λ _c = 0.2714P + 4.6833 (Formula 1)
Here, the lattice spacing P = P1 = P2

Therefore, if the wavelength λ _c (reflection wavelength in the concrete) of an arbitrary target frequency f to be shielded by the RC wall 1 is substituted into the above equation 1, the front reinforcing bar grid 3 or the rear reinforcing bar grid 4 and the welded wire mesh 6 are half It is possible to obtain a lattice interval P necessary for resonating electromagnetic waves in the wall as a transmission surface. In addition, in using Formula 1 or the wavelength linear graph WL, if it is within a predetermined allowable error range, an effect of shielding electromagnetic waves around the target frequency can be obtained, so when actually building the RC wall 1 The lattice interval P can be changed within an allowable error range (for example, an error within a reinforcing bar diameter or a secondary reinforcing bar diameter).

For example, since the wavelength (reflection wavelength) λ _{c in} the concrete when the frequency is 2.4 GHz is 52.8 mm, it can be seen from Equation 1 or the wavelength linear graph WL that the lattice spacing P should be 177 mm. Then, 59 mm, which is one third of the lattice interval P, is the lattice interval S of the welded wire mesh 6.
On the other hand, the distance D3 between the secondary reinforcing bar surface 60 of the welded wire mesh 6 and the reinforcing bar surface 40 of the rear reinforcing bar lattice 4 is 50.9 mm, and one wavelength λ _c = 52.8 mm and an allowable error range (reinforcing bar diameter (10 mm) or secondary reinforcing bar). (Diameter (3.2mm))
The rebar surfaces 30, 40 and the sub-rebar surface 60 are within the diameter (rebar diameter or sub-rebar diameter) of the rebar (31, 32, 41, 42) serving as the conductor rod or the wire (61, 62) serving as the sub-conductor rod. The reason why the distance can be changed is that the position of the reflection surface of the actual electromagnetic wave becomes the surface of the conductor rod or the sub conductor rod. Furthermore, when the surfaces (30, 40, 60) where the conductor rods or the sub conductor rods intersect and contact each other are used as the semi-transmissive surface, for example, in the vicinity of the location where the conductor rods intersect, Since there is a possibility that the position and the actual reflection position are shifted at the maximum by about the diameter of the conductor rod, resonance can be caused even if the position is changed within the range of the diameter of the conductor rod.

Next, the effect | action of the reinforced concrete partition (RC wall 1) of this Embodiment is demonstrated.
The RC wall 1 of the present embodiment configured as described above has a plurality of vertical wires 61 at a substantially central position between the front reinforcing bar lattice 3 and the rear reinforcing bar lattice 4 embedded in the concrete portion 2. ,... And a plurality of horizontal wires 62,.
Then, the lattice spacing S of the welded wire mesh 6 is P: S = 3n: 1 (n is a positive integer excluding 0) with respect to the lattice spacing P of the front reinforcing steel lattice 3 and the rear reinforcing steel lattice 4. It has been adjusted. The ratio between the lattice spacing P and the lattice spacing S is a ratio that can greatly attenuate the propagation of electromagnetic waves of the target frequency.
Furthermore, the distance D3 (C3-D3-E1) between the reinforcing bar surface 30 of the front reinforcing bar lattice 3 and the reinforcing bar surface 40 of the rear reinforcing bar lattice 4 and the secondary reinforcing bar surface 60 of the welded wire mesh 6 is also in the electromagnetic wave of the target frequency. It is adjusted to a substantially integer multiple of one wavelength (reflection wavelength) λ _c (the integer is a positive integer excluding 0).

For example, the wavelength λ _c of the target frequency f desired to be shielded by the RC wall 1 is calculated by the above conversion formula. And in order to attenuate electromagnetic waves by the phenomenon according to the resonance between the reinforcing bar surface 40 (30) of the rear reinforcing bar lattice 4 (or the front reinforcing bar lattice 3) and the secondary reinforcing bar surface 60 of the welded wire mesh 6, the reinforcing bar surface 40 (30) and the secondary rebar surface 60 are configured to be able to act as a semi-transmission surface for electromagnetic waves.
That is, by substituting the wavelength lambda _c of the target frequency f in Equation 1, to calculate the lattice pitch P of the front reinforcing bar grating 3 and the rear rebar grid 4 (spacing P1, P2). In addition, the grating | lattice space | interval P can also be calculated | required using the wavelength linear graph WL of FIG. Then, one third of the lattice interval P is set as the lattice interval S (interval S1, S2) of the welded wire mesh 6.
Further, the thickness direction (the propagation direction of the electromagnetic wave) between the reinforcing bar surface 40 (30) of the rear reinforcing bar lattice 4 (or the front reinforcing bar lattice 3) and the auxiliary reinforcing bar surface 60 of the welded wire mesh 6 that is desired to act as a semi-transmission surface of electromagnetic waves. Adjust the positional relationship. That is, setting the position of the front reinforcing bar grating 3, the rear rebar grid 4 and welded wire mesh 6 as the distance D3 and distance shown in FIG. 1 (C3-D3-E1) is the same length as the substantially wave lambda _c To do.

In this way, the RC wall 1 itself inevitably constructed as a structure can be obtained simply by arranging the welded wire mesh 6 having an appropriate lattice spacing S at an appropriate position between the front reinforcing bar lattice 3 and the rear reinforcing steel lattice 4. The electromagnetic wave having the target frequency f can be shielded.
In particular, the electromagnetic shielding effect can be further enhanced by causing both the front reinforcing bar lattice 3 and the rear reinforcing bar lattice 4 to function as semi-transmissive surfaces.

  That is, the RC wall 1 constructed in this way exhibits an electromagnetic wave shielding function by embedding the welded wire mesh 6 after adjusting the intervals P1 and P2 between the reinforcing bars of the reinforced concrete wall that must be constructed as a structure. be able to. For this reason, material cost can be reduced compared with the conventional case where the electromagnetic wave shielding member must be separately attached to the surface of the wall. In addition, the work is almost the same as the work of constructing the reinforced concrete wall itself, and can be easily constructed with little additional work for adding an electromagnetic shielding function.

  Here, as a building for constructing such an RC wall 1, there are a data center, a server room, a broadcasting studio, a photography studio, an airport radar control room, an office where a wireless LAN can be used, an electromagnetic shielding room, and the like.

  The RC wall 1 has a high electromagnetic shielding effect (SE) for the target frequency f, but can transmit electromagnetic waves of other frequencies. For this reason, it is possible to shield only electromagnetic waves having a specific frequency, such as wanting to receive mobile phone radio waves even inside buildings, but not letting radio LAN radio waves leak outside.

Moreover, such RC wall 1 can be constructed | assembled directly in the building construction site of a building. Furthermore, the precast panel which comprises RC wall 1 in a factory, a work yard, etc. can be manufactured previously, and it can also be set as RC wall 1 by assembling a precast panel in a construction site.
And if it is a method which manufactures a precast panel in a factory etc., it can be stably arrange | positioning the front reinforcement lattice 3, the rear reinforcement lattice 4, and the welding wire mesh 6 in the exact position by exact lattice spacing P and S. . Furthermore, since the concrete part 2 can also be formed with high quality, a stable quality RC wall 1 having a desired electromagnetic wave shielding function can be constructed.

  Next, a description will be given of a main conductor portion or sub-conductor portion in a form different from the front-side reinforcing bar lattice 3, the rear-side reinforcing bar lattice 4 or the welded wire mesh 6 described in the above embodiment. Note that the description of the same or equivalent parts as the contents described in the above embodiment will be described using the same terms and the same reference numerals.

  FIG. 10 is a perspective view of the winged reinforcing bar lattice 7 as the main conductor portion of the first embodiment. This winged reinforcing bar lattice 7 includes a plurality of second reinforcing bars 71,... As a plurality of first conductor rods erected in the vertical direction, and a plurality of second bars intersecting the vertical reinforcing bars 71 so as to be substantially perpendicular to each other. It forms in a grid | lattice form with the horizontal rebar 72 as a conductor rod. The square grid formed by the vertical reinforcing bars 71 and 71 and the horizontal reinforcing bars 72 and 72 is called a gap 73 here.

Further, as shown in FIG. 10, the vertical reinforcing bars 71 have wings 71 a and 71 a extending as widened portions on both the left and right sides. That is, the wings 71 a and 71 a are provided at positions facing each other with the vertical reinforcing bar 71 interposed therebetween. The wings 71 a and 71 a can be formed by fixing a strip-shaped steel plate along the longitudinal direction of the vertical reinforcing bar 71.
Further, as shown in FIG. 10, wings 72 a and 72 a as widening portions are extended to the horizontal reinforcing bar 72 on both the upper and lower sides. That is, the wings 72 a and 72 a are provided at positions facing each other with the horizontal reinforcing bar 72 interposed therebetween. The wings 72 a and 72 a can be formed by fixing a strip-shaped steel plate along the longitudinal direction of the horizontal reinforcing bar 72.

  The vertical reinforcing bar 71 and the horizontal reinforcing bar 72 from which the wings 71a and 72a are extended in this way are crossed with the wings 71a and 72a facing in the direction in which the gap 73 of the lattice becomes the narrowest. Here, when the surface of the wing portion 71a of the winged reinforcing bar lattice 7 and the surface of the wing portion 72a are arranged in parallel when viewed from the side, the projected area of the gap 73 is the narrowest.

  Thus, by providing the wings 71a, 72a on the vertical reinforcing bar 71 and the horizontal reinforcing bar 72, the distance between the horizontal reinforcing bars 72, 72 from the interval P11 by the wings 72a, 72a (or the interval P21 by the wings 71a, 71a). The lattice spacing can be considered widely up to P1 (or the spacing P2 between the vertical bars 71, 71). A wide lattice interval means that a plurality of lattice intervals P are included, and it means that frequencies corresponding to the respective lattice intervals can be resonated. That is, by providing the wings 71a and 72a, the bandwidth of the target frequency that can be resonated can be widened.

  The RC wall 1 on which the winged reinforcing bar lattice 7 configured as described above is arranged has a wide frequency band of electromagnetic waves that can be shielded, and therefore can effectively shield electromagnetic waves in a wide range.

  In the above description, the band-like wings 71a and 72a have been described as widened portions, but the present invention is not limited to this, and widening can be achieved by winding linear or tape-like steel materials around the vertical reinforcing bars 71 and the horizontal reinforcing bars 72. A part may be formed.

Further, the case where the widened portions (wing portions 71a, 72a) are provided in the main conductor portion has been described above, but in the same manner, the widened portions are also provided in the first subconductor rod and the second subconductor rod of the subconductor portion. Can be provided.
Other configurations and operational effects of the first embodiment are substantially the same as those in the above embodiment, and thus description thereof is omitted.

Next, a concrete part having a different form from the concrete part 2 described in the above embodiment will be described. Note that the description of the same or equivalent parts as those described in the above embodiment or Example 1 will be described using the same terms and the same reference numerals.
The concrete portion described in the second embodiment is formed so that the performance of absorbing electromagnetic waves is higher than when only normal concrete is used.

  For example, the concrete part itself can absorb the electromagnetic wave by forming a concrete part by mixing the concrete with a mixture for enhancing electromagnetic wave absorption performance such as conductive powder, conductive fiber or magnetic powder. it can. Here, as the conductive powder, carbon beads or metal powder having a particle diameter of 1 to 500 μm can be used. In addition, as the conductive fiber, carbon fiber, silicon carbide fiber, metal fiber, or the like having a fiber diameter of 5-30 μm and a fiber length of 1-20 mm can be used. Furthermore, as the magnetic powder, ferrite powder, titanium powder or magnet powder having a particle size of 3 to 500 μm can be used.

Moreover, even if air bubbles are mixed in concrete or porous concrete is used, the performance of absorbing the electromagnetic waves of the concrete part itself can be enhanced.
Other configurations and operational effects of the second embodiment are substantially the same as those of the above-described embodiment or the first embodiment, and thus description thereof is omitted.

  As mentioned above, although the reinforced concrete partition of this invention has been demonstrated based on embodiment and an Example, about a specific structure, it is not restricted to these embodiment etc., Unless it deviates from the summary of this invention, Design changes and additions are allowed.

  For example, in the above embodiment, the case of the outer wall that partitions the inner space R1 and the outer space R2 with the RC wall 1 has been described. However, the present invention is not limited to this, and the present invention is applied to the partition wall of the inner space. Can be applied. Moreover, it is not limited to a wall, A floor and a ceiling are good also as a reinforced concrete partition of this invention.

  Further, in the above-described embodiment or example, the case where the electromagnetic wave shielding structure of the present invention is provided in the reinforced concrete structure has been described, but the present invention is not limited thereto, and is molded by mortar, glass, acrylic, vinyl chloride, or the like. The electromagnetic shielding structure of the present invention can also be embedded in the formed partition. Furthermore, you may arrange | position the electromagnetic wave shield structure of this invention in the air.

In the above-described embodiment or example, the conductor rod is described as a reinforcing bar, and the sub conductor rod is described as a steel wire or a small diameter reinforcing rod. However, the present invention is not limited to this, and the conductor rod and the sub conductor rod are made of steel. It may be a metal rod such as a rod or a steel wire. Furthermore, the conductor rod and the sub conductor rod may have the same configuration. The “secondary” name is merely used for identification.
When using conductor bars or sub conductor bars other than reinforcing bars, change the grid spacing P, S and the distance between the main conductor part and the sub conductor part within the range of the thickness of the conductor bar or sub conductor bar. can do. The thickness of the conductor rod (or sub conductor rod) here is the distance (maximum cross-sectional diameter) between two points when taking the two most distant points on the cross section orthogonal to the axis of the conductor rod. For example, in the case of a conductor rod having a circular cross section, the diameter is the same, and in the case of a conductor rod having a rectangular cross section, the length of the diagonal line.

  In the above embodiment, the electromagnetic wave propagated from the internal space R1 to the external space R2 has been described as an example. However, the present invention is not limited to this, and is propagated from the external space R2 to the internal space R1. In the case of targeting electromagnetic waves, the main conductor portion and the sub conductor portion may be arranged based on the same concept.

  Moreover, in the said embodiment and Example, although the horizontal reinforcement 32 of the front reinforcement lattice 3 was arrange | positioned with respect to the vertical reinforcement 31 at the rear surface 12 side of the RC wall 1, it is not limited to this, The vertical reinforcement 31 On the other hand, the horizontal reinforcing bars 32 may be arranged on the front surface 11 side of the RC wall 1. Similarly, the horizontal reinforcing bars 42 of the rear reinforcing bar lattice 4 may be arranged on the rear surface 12 side of the RC wall 1 with respect to the vertical reinforcing bars 41.

  Moreover, although the said embodiment demonstrated the case where space | interval P1, P2 (S1, S2) was made equal as lattice space | interval P (S), it is not limited to this, Either one which becomes the same direction The interval P1 (P2) may be configured such that the interval S1 (S2) and P1 (P2): S1 (S2) = 3n: 1 (n is a positive integer excluding 0).

  Furthermore, in the said embodiment and Example, although the main conductor part (front side reinforcement lattice 3 and rear side reinforcement lattice 4) formed in the grid | lattice form was demonstrated, it is not limited to this, A vertical direction or horizontal The main conductor portion can also be constituted by a plurality of parallel conductor rods oriented in any one direction substantially orthogonal to the propagation direction such as the direction.

  In the above embodiment, the lattice-shaped welded wire mesh 6 has been described. However, the present invention is not limited to this, and a mesh-like subconductor portion that is not a welded wire mesh may be used. Furthermore, the sub conductor portion may be configured by a plurality of parallel sub conductor rods oriented in any one direction substantially orthogonal to the propagation direction such as the vertical direction and the horizontal direction instead of the lattice shape. That is, it is only necessary that the conductor rod and the sub conductor rod of the main conductor portion face the same direction.

  Moreover, although the said embodiment and Example demonstrated the case where the vertical reinforcement 31 (41, 71) and the horizontal reinforcement 32 (42, 72) were orthogonal, it is not limited to this, The 1st conductor The rod and the second conductor rod may intersect at an angle other than a right angle. Furthermore, the first conductor rod and the second conductor rod do not need to face the vertical direction or the horizontal direction, and may be arranged diagonally. In such a case, the first sub-conductor rod and the second sub-conductor rod of the sub conductor portion may be arranged diagonally in accordance with them.

  Moreover, in the said embodiment, although the welding wire mesh 6 was arrange | positioned in the approximate center of the distance C3 between the reinforcing bar surface 30 of the front reinforcing bar lattice 3, and the reinforcing bar surface 40 of the rear reinforcing bar lattice 4, it is limited to this. Instead, for example, the positional relationship may be such that only one of the reinforcing bar surface 30 and the reinforcing bar surface 40 is approximately an integral multiple of one wavelength with the auxiliary reinforcing bar surface 60.

  Furthermore, in the above-described embodiment, the case where the two main conductor portions of the front rebar lattice 3 and the rear rebar lattice 4 are provided has been described. However, the present invention is not limited to this, and the front rebar lattice 3 or the rear rebar lattice 4 may be a combination of one main conductor portion and sub conductor portion.

Although not provided in the above embodiment, an electromagnetic wave shield such as an iron plate, a metal net, a metal foil, a metal mesh, or a ferrite material is disposed between the interior board 5 and the RC wall 1. The effect can be enhanced.

Claims (9)

An electromagnetic shielding structure that attenuates electromagnetic waves of a target frequency that propagates in a predetermined propagation direction,
A main conductor portion formed by a plurality of first conductor rods arranged side by side at a constant interval in a direction substantially orthogonal to the propagation direction;
Formed by a plurality of first sub-conductor rods arranged side by side at a certain distance in the same direction as the first conductor rod at a position spaced from the main conductor portion in the propagation direction. A sub conductor portion,
The distance in the propagation direction between the main conductor portion and the sub conductor portion is an integral multiple of one wavelength depending on the medium interposed between the main conductor portion and the sub conductor portion of the target frequency (here, , The integer is a positive integer excluding 0) and is set with an error within the diameter of the first conductor rod or the first sub conductor rod ,
The interval between the first conductor rods or the first conductor rods is based on a length of an integral multiple of 3 (the integer is a positive integer excluding 0) as the interval between the first conductor rods. An electromagnetic shielding structure characterized by being set with an error within the diameter of the conductor rod . The main conductor portion has a plurality of second conductor rods arranged side by side at regular intervals so as to intersect the first conductor rods,
The said subconductor part has a some 2nd subconductor rod arrange | positioned along with a fixed space | interval toward the substantially same direction as the said 2nd conductor rod. Electromagnetic wave shield structure.   The electromagnetic shielding structure according to claim 2, wherein the first conductor rod and the second conductor rod are substantially orthogonal to each other.   4. The electromagnetic shielding structure according to claim 1, wherein the sub conductor portion is disposed between the two main conductor portions that are disposed at an interval in the propagation direction. 5. .   A widening portion is provided that extends in a direction in which a gap between the first conductor rod, the second conductor rod, the first sub conductor rod, and the second sub conductor rod is narrowed. The electromagnetic wave shielding structure according to any one of claims 1 to 4, wherein   A reinforced concrete partition body in which the electromagnetic wave shielding structure according to any one of claims 1 to 5 is embedded in a concrete portion having the propagation direction as a thickness direction. A reinforced concrete partition body in which the electromagnetic wave shielding structure according to claim 2 or 3 is embedded in a concrete portion having the propagation direction as a thickness direction,
The interval between the first conductor rods and the interval between the second conductor rods is equal to the lattice interval P and satisfies λ _c = 0.2714P + 4.6833 in relation to the wavelength λ _c in the concrete portion of the target frequency. The reinforced concrete partition body, wherein the lattice interval P is set with an error within a diameter of the first conductor rod or the first sub-conductor rod based on a value.   The reinforced concrete partition according to claim 6 or 7, wherein the concrete part is mixed with a mixed material or air bubbles for improving electromagnetic wave absorption performance.   The reinforced concrete partition according to any one of claims 6 to 8, which is formed into a panel shape.

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