JP2002026570A - Electromagnetic wave absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an electromagnetic wave absorbing area to be wide. SOLUTION: In an electromagnetic wave absorbing panel 3, three insulating substrates are arranged in parallel by leaving spaces. A matching film which absorbs a part of an arriving electromagnetic wave, makes the other part reflect and makes the remainder pass through, a division conductive film 22 and a reflection film reflecting the arriving electromagnetic wave are formed on the respective substrates in order from the arriving direction of the electromagnetic wave. A plurality of conductive patterns 24 which have shapes where change patterns whose width (b) changes like bmax→bmin→bmax are repeated at a prescribed period and which have film thickness (a) are disposed by leaving gaps 26 along the width direction. The width (d) of the gap 26 changes like dmin→dmax→dmin. The change ranges bmin to bmax of width (b) and the change ranges dmin to dmax of width (d) are decided in accordance with the frequency bands f1 to f22 of the electromagnetic wave to be absorbed. The electromagnetic wave arrived at the electromagnetic wave absorbing panel is absorbed at a high absorbing rate for the whole frequency bands f1 to f2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave absorber, and more particularly, to an electromagnetic wave absorber that absorbs an electromagnetic wave by superimposing an electromagnetic wave having an opposite phase on the electromagnetic wave to be absorbed.

[0002]

2. Description of the Related Art At present, electromagnetic waves (radio waves) are radio, TV,
It is used in various fields such as mobile phones, wireless communications, and the like. However, so-called radio interference, which causes various inconveniences due to interference of these electromagnetic waves with other electromagnetic waves, has conventionally been a problem. Examples of the electromagnetic waves that cause radio interference include electromagnetic waves reflected from buildings such as buildings and steel towers, and unnecessary electromagnetic waves radiated from electric and electronic devices. Among them, especially T of VHF and UHF
The electromagnetic wave in the V frequency band is reflected by the building, and the electromagnetic wave (direct wave) directly arriving from the station to the receiving antenna and the electromagnetic wave (reflected wave) reflected by the outer wall of the building are incident on the receiving antenna. The reception obstacle has become a social problem with the increase of high-rise buildings in recent years.

Various types of electromagnetic wave absorbers for absorbing electromagnetic waves have been conventionally proposed. For example, an absorber that reflects, absorbs and transmits an incoming electromagnetic wave, and a reflector that reflects an incoming electromagnetic wave are used. A λ / 4 type electromagnetic wave absorber having a configuration arranged at a distance corresponding to １ ／ of the wavelength of the electromagnetic wave to be absorbed is compared with a widely known electromagnetic wave absorber using a magnetic material such as ferrite. Thus, it has the advantage of being lightweight and inexpensive to manufacture. In addition, by using a member having light transmissivity, it is also possible to apply to a window of a building.

In a λ / 4 type electromagnetic wave absorber in which the space between the absorber and the reflector is filled with air, the absorber is used to absorb a relatively low-frequency electromagnetic wave in the VHF band (for example, about 100 MHz). And the reflector must be separated by about several tens of centimeters, which is disadvantageous in that it is too thick to be attached to a window or a wall of a building. For this reason, by disposing a conductive film coated in a stripe or lattice shape between the absorber and the reflector of the λ / 4 type electromagnetic wave absorber, the effective distance between the absorber and the reflector is improved. A technique for increasing the relative dielectric constant has also been proposed (see JP-A-10-275997). According to the above technique, a λ / 4 type electromagnetic wave absorber that absorbs electromagnetic waves in the VHF band can be realized with a thickness of about 10 cm.

[0005]

However, λ / 4
The electromagnetic wave absorber is reflected by the reflector and transmitted through the absorber, including the configuration in which the striped or lattice-shaped conductive coating is disposed between the absorber and the reflector as described above, and is emitted. Since the electromagnetic wave uses the fact that it has an opposite phase to the electromagnetic wave reflected and emitted by the absorber, its absorption characteristics are limited to electromagnetic waves within a very narrow frequency band centered on the opposite phase frequency. It shows the property of absorbing at a high absorption rate. Therefore, there is a problem that electromagnetic waves cannot be absorbed over a wide frequency band.

The present invention has been made in view of the above-mentioned facts, and has as its object to provide an electromagnetic wave absorber capable of realizing a wider electromagnetic wave absorption band.

[0007]

According to a first aspect of the present invention, there is provided an electromagnetic wave absorber that reflects a part of an incoming electromagnetic wave and transmits another part of the electromagnetic wave. A reflection member that is arranged at a distance from the resistance member and reflects an incoming electromagnetic wave, and is provided between the resistance member and the reflection member, and extends along a direction that intersects a direction in which the resistance member and the reflection member are arranged. And a dielectric member whose relative permittivity ε _S is changed regularly or irregularly according to the frequency band of the electromagnetic wave to be absorbed.

According to the first aspect of the present invention, the resistance member that reflects a part of the arriving electromagnetic wave and transmits the other part and the reflection member that reflects the electromagnetic wave are arranged at a distance.
When an electromagnetic wave arrives from the resistance member side, a part of the arriving electromagnetic wave is reflected by the resistance member, and another part is transmitted through the resistance member, enters the reflection member, is reflected by the reflection member, and is again reflected on the resistance member. Incident. Then, part of the electromagnetic wave that has re-entered the resistance member is reflected by the resistance member, and another part of the electromagnetic wave transmits through the resistance member.

With the resistance member and the reflection member, the phase of the electromagnetic wave reflected by the resistance member and emitted from the electromagnetic wave absorber (referred to as a primary emission electromagnetic wave for convenience) is transmitted through the resistance member after being reflected by the reflection member. As for the electromagnetic wave in the frequency band in which the phase of the electromagnetic wave emitted from the electromagnetic wave absorber (referred to as a secondary emission electromagnetic wave for convenience) is substantially opposite, the secondary emission electromagnetic wave having substantially opposite phase is superimposed on the primary emission electromagnetic wave. Thus, the electromagnetic wave emitted from the electromagnetic wave absorber is attenuated and absorbed, similarly to the λ / 4 type electromagnetic wave absorber.

Here, the wavelength λ of an electromagnetic wave propagating through a certain medium is represented by f representing the frequency of the electromagnetic wave and ε (= ε _S
ε ₀ : ε _S is relative permittivity, ε ₀ is vacuum permittivity, and the magnetic permeability of the medium is μ (= μ _S μ ₀ : μ _S is relative magnetic permeability, μ ₀ is vacuum magnetic permeability). Since λ = 1 / f√ (εμ) (1), the wavelength λ changes according to the dielectric constant of the medium.
Therefore, the frequency band in which the phase of the secondary emission electromagnetic wave is substantially opposite to the phase of the primary emission electromagnetic wave is between the resistance member and the reflection member even if the distance between the resistance member and the reflection member is constant. It changes according to the dielectric constant of the existing medium.

According to the first aspect of the present invention, according to the frequency band of the electromagnetic wave to be absorbed, between the resistance member and the reflection member, along the direction intersecting the direction in which the resistance member and the reflection member are arranged. A dielectric member whose relative dielectric constant ε _S is changed regularly or irregularly is provided. It is preferable that the dielectric member includes a plurality of conductors arranged in a certain direction at an interval, for example, as described in claim 2. However, the dielectric member is formed using a known dielectric material (for example, It is also possible to use a combination of a plurality of types of dielectric materials having different dielectric constants ε _S and to change the ratio of the plurality of types of dielectric materials regularly or irregularly along the intersecting direction. is there.

[0012] The dielectric constant epsilon _S of the dielectric member, if the frequency band in which the frequency band of the electromagnetic wave is continuous over from the lowest frequency f ₁ to the highest frequency f ₂ for example to be absorbed, the lowest frequency f ₁ electromagnetic waves of wavelength lambda divided by the ₁ in 4 (lambda _1/4) the dielectric constant to match the distance between the resistive member and the reflecting member epsilon ₁ (relative permittivity epsilon _S1) the previous (1) with determined based on equation, the maximum frequency f ₂ of the electromagnetic wave of the wavelength lambda divided by the ₂ by 4 (lambda _2/4), the dielectric constant to match the distance between the resistive member and the reflecting member epsilon ₂ (ratio Dielectric constant ε
Determined based on the _S2) in the previous (1), the relative dielectric constant epsilon _S of the dielectric member, it suffices regular or non-regular changed within the range of ε _S1 ~ε _S2.

Further, for example, there are a plurality of discrete frequency bands of electromagnetic waves to be absorbed (frequency bands f _{a1 to} f _a2 ,
f _{b1 to} f _b2 ,...), the relative permittivity corresponding to the lowest frequency and the relative permittivity corresponding to the highest frequency are obtained for each frequency band based on the equation (1), and the relative permittivity of the dielectric member is obtained. ε _S
May be changed regularly or irregularly within a range corresponding to each frequency band.

By providing the above dielectric member between the resistance member and the reflection member, the frequency band in which the primary emission electromagnetic wave and the secondary emission electromagnetic wave are substantially in opposite phases, that is, the attenuation of the electromagnetic wave emitted from the electromagnetic wave absorber. The frequency band in which absorption occurs changes regularly or irregularly along the direction intersecting the direction in which the resistance member and the reflection member are arranged, and the attenuation of the electromagnetic wave over the entire frequency band of the electromagnetic wave to be absorbed.・
Absorption can occur. Therefore, according to the first aspect of the present invention, it is possible to widen the electromagnetic wave absorption band.

According to a second aspect of the present invention, there is provided an electromagnetic wave absorber, wherein a resistance member that reflects a part of an incoming electromagnetic wave and transmits another part is disposed at a distance from the resistance member.
A reflecting member that reflects an incoming electromagnetic wave, and a plurality of reflecting members are provided between the resistance member and the reflection member, and are arranged at intervals along a direction intersecting a direction in which the resistance member and the reflection member are arranged. A conductor, and an electromagnetic wave absorber configured to include, the plurality of conductors, so that the effective relative permittivity changes regularly or irregularly according to the frequency band of the electromagnetic wave to be absorbed, At least one of a width of the conductor along the intersecting direction, a gap between the conductors along the intersecting direction, and a thickness of the conductor along the juxtaposing direction is changed regularly or irregularly. It is characterized by:

According to the second aspect of the present invention, since the same resistance member and reflection member as those of the first aspect of the present invention are provided, the electromagnetic wave in the frequency band in which the primary emission electromagnetic wave and the secondary emission electromagnetic wave have substantially opposite phases. When the electromagnetic waves arrive from the resistance member side, the electromagnetic waves emitted from the electromagnetic wave absorber according to the electromagnetic waves are attenuated and absorbed.

According to the second aspect of the present invention, a plurality of conductors are provided between the resistance member and the reflection member at intervals along a direction intersecting the direction in which the resistance member and the reflection member are arranged. ing. When a plurality of conductors are arranged as described above, the effective relative permittivity ε between the resistance member and the reflection member
_eff is the dielectric constant of the medium existing between the conductor and the resistance member and between the conductor and the reflection member, ε _a , ε _b , the width of the conductor along the direction intersecting the direction in which the resistance member and the reflection member are arranged. When the distance is b and d, and the thickness of the conductor along the direction in which the resistance member and the reflection member are arranged is a, the following expression (2) is obtained.

[0018]

(Equation 1)

As is apparent from the above equation (2), the effective relative permittivity ε _eff is the conductor width b along the direction intersecting the direction in which the resistance member and the reflection member are arranged, and the interval along the intersecting direction. d and the thickness a of the conductor along the direction in which the resistance member and the reflection member are arranged. The frequency band in which the phase of the secondary emission electromagnetic wave is substantially opposite to the phase of the primary emission electromagnetic wave changes according to the dielectric constant of a medium existing between the resistance member and the reflection member. The frequency of the electromagnetic wave attenuated and absorbed by the electromagnetic wave absorber according to the invention is the width of the conductor along the direction that intersects the direction in which the resistance member and the reflection member are arranged, and the direction that intersects the direction in which the resistance member and the reflection member are arranged. The distance varies depending on the gap between the conductors along the gap and the thickness of the conductor along the direction in which the resistance member and the reflection member are arranged.

According to the second aspect of the present invention, the direction intersecting the direction in which the resistance member and the reflection member are arranged so that the effective relative permittivity changes regularly or irregularly according to the frequency band of the electromagnetic wave to be absorbed. At least one of the width of the conductor along the width direction, the gap between the conductors along the direction intersecting the direction in which the resistance member and the reflection member are arranged, and the thickness of the conductor along the direction in which the resistance member and the reflection member are arranged are regular or irregular. Since the frequency is regularly changed, the frequency of the electromagnetic wave attenuated and absorbed by the electromagnetic wave absorber according to the second aspect of the present invention is regularly or irregularly along a direction intersecting the direction in which the resistance member and the reflection member are arranged. It will change regularly. Therefore, according to the second aspect of the present invention, it is possible to widen the absorption band of the electromagnetic wave in which the direction of the polarization plane is substantially perpendicular to the first direction.

The dielectric constant (effective relative dielectric constant _eff obtained by equation (2)) obtained by arranging a plurality of conductors in a fixed direction at an interval as in the second aspect of the present invention is as follows. By appropriately setting the thickness a of the conductor, the width b of the conductor, and the distance d, it is possible to easily realize a value significantly larger than 1 (ε _eff ≫1). Even when the frequency band of the electromagnetic wave is relatively low, it is possible to prevent the distance between the resistance member and the reflection member from becoming extremely large.

By the way, the dielectric constant (effective relative dielectric constant ε _eff obtained by equation (2)) obtained by arranging a plurality of conductors in a fixed direction at an interval is described in detail in the arrangement direction of the plurality of conductors. The dielectric constant in the arrangement direction of the plurality of conductors acts on an electromagnetic wave whose polarization plane is substantially perpendicular to the arrangement direction of the plurality of conductors.

According to another aspect of the present invention, a plurality of conductors are arranged at intervals along a single direction that intersects the direction in which the resistance member and the reflection member are arranged (a stripe shape). In this configuration, at least one of the thickness a of the conductor, the width b of the conductor, and the interval d is changed regularly or irregularly, so that a single direction is provided. Only the effective relative permittivity ε _eff changes regularly or _irregularly , and among electromagnetic waves arriving at the electromagnetic wave absorber, acts only on electromagnetic waves whose polarization plane direction is substantially orthogonal to the single direction. I do.

Therefore, in the above configuration, the electromagnetic wave whose polarization plane direction is constant and which is substantially orthogonal to the single direction (for example, only horizontally polarized electromagnetic wave or only vertically polarized electromagnetic wave) can be broadband. , But the direction of the plane of polarization is indeterminate (for example, a circularly polarized electromagnetic wave),
It is difficult to absorb a plurality of types of electromagnetic waves having different polarization plane directions (for example, horizontally polarized electromagnetic waves and vertically polarized electromagnetic waves) over a wide band.

According to the third aspect of the present invention, the plurality of conductors are arranged at intervals along a first direction intersecting the direction in which the resistance member and the reflection member are arranged. At least one of the width and the gap of the conductor along the first direction is regular so that the effective relative permittivity in the first direction varies regularly or irregularly according to the frequency band of the electromagnetic wave to be absorbed. Or irregularly changed, and arranged at intervals along a second direction intersecting the line-up direction and the first direction, respectively, and arranged in a second direction according to a frequency band of an electromagnetic wave to be absorbed. Characterized in that at least one of the width and the gap of the conductor along the second direction is changed regularly or irregularly so that the effective relative permittivity of the conductor changes regularly or irregularly. .

According to the third aspect of the present invention, the plurality of conductors are:
The resistive member and the reflective member are arranged at intervals along a first direction intersecting the direction in which the resistive member and the reflective member are arranged, and are arranged along the direction in which the resistive member and the reflective member are arranged and in a second direction intersecting the first direction, respectively. , The effective relative permittivity ε _eff in the first direction changes according to the width and spacing of the conductors along the first direction (and the thickness of the conductors along the aligned direction). , The effective relative permittivity ε _{eff in} the second direction
Varies according to the width and spacing of the conductors in the second direction (and the thickness of the conductors in the direction in which the conductors are arranged).

According to the third aspect of the present invention, the first relative permittivity in the first direction changes regularly or irregularly according to the frequency band of the electromagnetic wave to be absorbed.
At least one of the width and the gap of the conductor along the direction is changed regularly or irregularly, and the effective relative permittivity in the second direction is regular or irregular depending on the frequency band of the electromagnetic wave to be absorbed. Since at least one of the width and the gap of the conductor along the second direction is changed regularly or irregularly so as to change regularly, regardless of the direction of the plane of polarization of the electromagnetic wave, the electromagnetic wave absorption band can be changed. Broadband can be realized.

By the way, as is apparent from equation (1),
In order to minimize the distance between the resistance member and the reflection member of the electromagnetic wave absorber, it is important to increase the effective relative permittivity between the resistance member and the reflection member as much as possible. In order to increase the effective relative dielectric constant as much as possible, as is apparent from the equation (2), it is effective to reduce the thickness a of the conductor along the direction in which the resistance member and the reflection member are arranged as small as possible.

In view of the above, it is preferable that a plurality of conductors be formed on a substrate made of an insulating material. By forming a plurality of conductors on the substrate, it is possible to easily realize a very small thickness (for example, a film shape) of the conductors along the direction in which the resistance member and the reflection member are arranged, and it is possible to absorb electromagnetic waves. It is possible to make the distance between the resistance member of the body and the reflection member smaller.

The resistance member according to the first or second aspect of the present invention can be configured to reflect a part of the arriving electromagnetic wave and transmit all the rest,
As described in claim 5, a structure comprising a substrate made of an insulating material, and a conductive film formed on the substrate by adjusting the conductivity so as to absorb a part of an incoming electromagnetic wave. Is preferred.

The electromagnetic wave absorber according to the present invention attenuates and absorbs the electromagnetic wave emitted from the electromagnetic wave absorber by superimposing the secondary emission electromagnetic wave of substantially opposite phase on the primary emission electromagnetic wave.
In practice, part of the electromagnetic wave that is reflected by the reflecting member and then enters the resistive member is reflected by the resistive member (the other part is emitted as a secondary emission electromagnetic wave), thereby re-entering the reflective member. Since the amplitudes of the primary emission electromagnetic wave and the secondary emission electromagnetic wave are not almost the same in most cases, it is difficult to completely absorb the emitted electromagnetic wave, and the electromagnetic wave reflected by the reflection member is hardly absorbed. By repeating the phenomenon of being reflected by the resistance member, an n-th order emission electromagnetic wave of n ≧ 3 (n is equivalent to the number of times of incidence on the resistance member) is also emitted.

On the other hand, according to the fifth aspect of the present invention, since the conductivity of the conductive film constituting the resistance member is adjusted so as to absorb a part of the arriving electromagnetic wave, the electromagnetic wave is applied to the resistance member. Every time is incident, a part thereof is attenuated by being absorbed by the resistance member, and the electromagnetic wave emitted from the electromagnetic wave absorber according to the present invention can be further reduced.

Further, the reflecting member according to the first or second aspect of the present invention also has the following features.
It can be configured to include a substrate made of an insulating material, and a conductive film formed on the substrate.

Further, in the invention according to any one of claims 1 to 6, each member constituting the electromagnetic wave absorber is
As described in claim 7, it may be substantially transparent. This makes it possible to apply the electromagnetic wave absorber according to the present invention to a window of a building or the like.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

[First Embodiment] FIG. 1 shows an electromagnetic wave absorbing panel 10 as an electromagnetic wave absorber according to the first and second aspects of the present invention. The electromagnetic wave absorbing panel 10 includes plate-like insulating substrates 12 and 14 which are arranged in parallel at a predetermined interval. Insulating substrate 12,
14 can be formed by selectively using an arbitrary material from various known insulating materials to form a flat plate, and it is required that the electromagnetic wave absorbing panel 10 has light transmittance. (For example, the electromagnetic wave absorbing panel 10
(For example, when used as a window of a building), it can be made of a material such as glass or vinyl or plastic having optical transparency.

A conductive film (resistive film) 16 is formed on the surface of the insulating substrate 12 facing the insulating substrate 14. When the electromagnetic wave arrives, the electrical conductivity (resistance per unit area: sheet resistance) of the resistance film 16 is adjusted so that a part of the resistance film 16 is absorbed, another part is reflected, and the other part is transmitted. I have. The sheet resistance suitable for the resistance film 16 is about 50Ω to 3000Ω per unit area, and more preferably about 200Ω to 1500Ω per unit area.
The insulating substrate 12 corresponds to the substrate described in claim 5, and the resistance film 16 corresponds to the conductive film described in claim 5,
The insulating substrate 12 and the resistance film 16 correspond to the resistance member according to the present invention.

A conductive film (reflection film) 1 is formed on the surface of the insulating substrate 14 facing the insulating substrate 12.
8 are formed. The conductivity (surface resistance) of the reflective film 18 is adjusted so that most of the arriving electromagnetic waves are reflected. The sheet resistance suitable for the reflection film 18 is 1Ω per unit area.
About 30Ω, more preferably 5Ω per unit area.
If the electromagnetic wave absorbing panel 10 is not required to have optical transparency, the sheet resistance can be made smaller, and the reflection ratio of the incoming electromagnetic wave can be made higher. . The insulating substrate 14
Corresponds to the substrate described in claim 6, the reflection film 18 corresponds to the conductive film described in claim 6, and the insulating substrate 14 and the reflection film 18 correspond to the reflection member according to the present invention.

In the gap between the insulating substrate 12 and the insulating substrate 14, a flat insulating substrate 20 is disposed at an intermediate portion thereof substantially in parallel with the insulating substrates 12 and 14. The space between the insulating substrate 12 and the insulating substrate 20 and the space between the insulating substrate 14 and the insulating substrate 20 are filled with air. On one surface of the insulating substrate 20, a divided conductive film 22 is formed on the entire surface.

As shown in FIG. 2, in the divided conductive film 22 according to the first embodiment, a substantially long conductive pattern 24 having a constant film thickness a is formed in a width direction orthogonal to the longitudinal direction of the conductive pattern 24. Are arranged along a gap 26 with a gap 26 therebetween. Note that these conductive patterns 24 correspond to the plurality of conductors described in claim 2. Individual conductive pattern 24 is more information in the longitudinal direction of the conductive pattern 24, varies linearly from a maximum width b _max width b to the minimum width b _min, followed by linearly from the minimum width b _min to a maximum width b _max Has a regular shape repeated in a constant cycle. The sheet resistance suitable for the conductive pattern 24 is about 1 Ω to 40 Ω per unit area, and more preferably about 5 Ω to 20 Ω per unit area.

The plurality of conductive patterns 24 have a width b
Is the maximum width b _max and the width b is the minimum width b _min
The width d of the gap 26 is also set along the longitudinal direction of the conductive pattern 24 at the same cycle as the change cycle of the width b of the conductive pattern 24, so that the width d of the gap 26 is equal to the minimum width d. _min → maximum width d _max → minimum width d _min → ...
And it changes linearly and regularly. Note that changes in the width b of the conductive pattern 24 and the width d of the gap 26 may be non-linear.

In the first embodiment, the electromagnetic wave absorbing panel 1
0, the frequency band of the electromagnetic wave to be absorbed is continuous from the lowest frequency f ₁ to the highest frequency f ₂ , and the change range b _{min to} b _max of the width b of the conductive pattern 24 and the gap 2
The change range d _{min to} d _max of the width d of 6 is determined as follows based on the frequencies f ₁ and f ₂ .

[0043] That is, the first minimum frequency f ₁ of the electromagnetic wave of a wavelength lambda value obtained by dividing ₁ by 4 (λ _1/4), the dielectric constant to match the distance between the resistive film 16 and the reflective film 18 epsilon ₁ ( dielectric constant epsilon _S1) together with determined based on the above equation (1), divided by the electromagnetic wave of the highest frequency f ₂ of the wavelength lambda ₂ with 4 (lambda ₂ /
In 4), the dielectric constant ε ₂ (relative dielectric constant ε _S2 ) for matching the distance between the resistance member and the reflection member is obtained based on the above equation (1).

Then, from one of the relative dielectric constants ε _S1 and ε _S2 ,
The maximum width b of the conductive pattern 24 based on the above equation (2)
_{A set of max} and a minimum width d _min of the gap 26 is obtained, and
From the other of the relative dielectric constants ε _S1 and ε _S2, a set of the minimum width b _min of the conductive pattern 24 and the maximum width d _max of the gap 26 is obtained. As a result, the change range of the width b of the conductive pattern 24 and the change range of the width d of the gap 26 for absorbing the electromagnetic waves of each frequency within the electromagnetic wave absorption band at a high absorption rate are obtained.

The resistive film 16, the reflective film 18, and the conductive pattern 24 are formed on the insulating substrate 12 or the insulating substrate 14 or on the insulating substrate 14 by selectively using any of various known conductive materials. When the electromagnetic wave absorbing panel 10 is required to have optical transparency, for example, a transparent conductive film mainly composed of SnO ₂ , A transparent conductive film mainly containing In ₂ O ₃ and a metal film mainly containing any of Ag, Au, Cu, and Al are preferable.

The above-mentioned transparent conductive film and metal film reflect near-infrared light contained in sunlight and have a characteristic of low radiation of heat rays. By using the configured electromagnetic wave absorbing panel 10 for a window of a building, it is possible to realize energy saving of indoor cooling and heating.

Next, the operation of the first embodiment will be described. The electromagnetic wave absorbing panel 10 is disposed, for example, in a window of a building or the like. (For example, when a horizontally polarized electromagnetic wave arrives, the vertical direction in FIG. 2 coincides with the vertical direction of the building) and the electromagnetic wave is transmitted from the resistive film 16 side. Arranged to arrive.

When an electromagnetic wave arrives at a building in a state where the electromagnetic wave absorbing panel 10 is disposed on the building as described above, the incoming electromagnetic wave (electromagnetic wave E ₀ shown in FIG. 3) as shown in FIG.
Is transmitted through the insulating substrate 12 and is incident on the resistive film 16, a part of which is reflected by the resistive film 16 and is emitted as the primary emission electromagnetic wave E _r1 , a part is absorbed by the resistive film 16, and the rest is 16 and is emitted to the reflection film 18 side as an electromagnetic wave _Et1 .

The electromagnetic wave _{Et 1} is transmitted through the divided conductive film 22 and the insulating substrate 20 and is incident on the reflective film 18. Most of the electromagnetic wave E _t1 is reflected by the reflective film 18. The light is transmitted and incident on the resistance film 16. A part of the electromagnetic wave E _t1 incident on the resistive film 16 passes through the resistive film 16 and is emitted as the secondary emission electromagnetic wave E _r2 , while a part is absorbed by the resistive film 16 and the rest is reflected by the resistive film 16. Then, it is emitted to the reflection film 18 side as an electromagnetic wave _Et2 .

Further, the electromagnetic wave _{Et 2} is transmitted through the divided conductive film 22 and the insulating substrate 20 and is incident on the reflective film 18, and most of the electromagnetic wave _{Et 2} is reflected by the reflective film 18, and passes through the insulating substrate 20 and the divided conductive film 22. The light is transmitted again and is incident on the resistance film 16. A part of the electromagnetic wave _{Et 2} incident on the resistive film 16 is transmitted through the resistive film 16 and emitted as a tertiary emission electromagnetic wave _Er 3, and a part is absorbed by the resistive film 16 and the rest is reflected by the resistive film 16. It is emitted to the reflection film 18 side as an electromagnetic wave _Et3 .

By repeating the above-mentioned phenomenon, the electromagnetic wave arriving at the electromagnetic wave absorbing panel 10 becomes the primary emission electromagnetic wave to
Since (theoretically n _MAX = ∞) n _MAX order electromagnetic wave is divided into emitted from the electromagnetic wave absorption panel 10, the reflection coefficient of the electromagnetic wave absorbing panel 10 coming from the resistance film 16 is formed the insulating substrate 12 side Γ

[0052]

(Equation 2)

Is as follows.

Here, part of the electromagnetic wave incident on the resistive film 16 is absorbed by the resistive film 16 so that the electric field intensity of the electromagnetic wave transmitted through the resistive film 16 or reflected by the resistive film 16 and emitted is reduced. Become smaller. The order n of the n-th emitted electromagnetic wave indicates the number of times the corresponding electromagnetic wave is incident on the resistive film 16, and the number of incidents on the resistive film 16 increases as the value of the order n increases. Although depending on the value of the absorptivity α of the electromagnetic wave, a higher-order emission electromagnetic wave having a large order n (for example, an emission electromagnetic wave of n ≧ 3) can be neglected because the electric field intensity becomes very small.

Further, in the electromagnetic wave absorbing panel 10 according to the present embodiment, the effective relative dielectric constant in the arrangement direction of the conductive patterns 24 between the resistive film 16 and the reflective film 18 is determined by the width b of the conductive patterns 24 (2 )), The width d of the conductor and the width d of the gap 26 are used as the distance d in the equation (2), and the film thickness a is used as the thickness a of the conductor in the equation (2). It matches the dielectric constant ε _eff .

As described above, in this embodiment,
The relative dielectric constants ε _S1 and ε _S2 corresponding to the lowest frequency f ₁ and the highest frequency f ₂ of the frequency band of the electromagnetic wave to be absorbed by the electromagnetic wave absorbing panel 10 are obtained, and the conductive pattern 24 is obtained.
Of the maximum width b _max and the minimum width d _min of the gap 26 and the pair of the minimum width b _min of the conductive pattern 24 and the maximum width d _max of the gap 26 are determined, and the width b of the conductive pattern 24 is changed to the change range b _min with varying regularly in ~b _max, it is regularly varied within the variation range d _min to d _max width d of the gap 26.

Therefore, in the electromagnetic wave absorbing panel 10 according to the first embodiment, the effective relative permittivity in the arrangement direction of the conductor patterns 24 between the resistive film 16 and the reflection film 18 is longer in the longitudinal direction of the conductor patterns 24. Along ε _S1 → ε _S2 → ε _S1 →…
And the wavelength of the electromagnetic wave _Etn reciprocatingly propagating between the resistive film 16 and the reflective film 18 with the periodic change of the effective relative permittivity (formula (1)). See also
It changes continuously and periodically along the longitudinal direction of the conductor pattern 24.

The primary emission electromagnetic wave E _r1 and the secondary emission electromagnetic wave E _r2
Of the phase difference corresponds to the remainder when dividing the propagation distance of the electromagnetic waves E _t1 at the wavelength of the electromagnetic waves E _t1, primary injection electromagnetic wave E _r1
And the secondary emission electromagnetic wave E _r2 have a substantially opposite phase (λ / 2), that is, the primary emission electromagnetic wave E _r1 and the secondary emission electromagnetic wave E _r2 emitted from the electromagnetic wave absorbing panel 10 cancel each other out. The center frequency of the frequency band that is attenuated / absorbed along the longitudinal direction of the conductor pattern 24 is
It changes continuously and periodically in the range of f _{1 to} f ₂ , and the electromagnetic wave E ₀ arriving at the electromagnetic wave absorbing panel 10 (provided that the direction of the polarization plane is the conductive pattern 24 of the divided conductive film 22)
(Only the electromagnetic waves substantially perpendicular to the arrangement direction) can be absorbed at a high absorption rate over the entire frequency band f _{1 to} f ₂ of the electromagnetic waves to be absorbed.

Further, as described above, if the electromagnetic wave absorbing panel 10 is made of a member having light transmitting properties, the electromagnetic wave absorbing panel 10 having light transmitting properties can be obtained. It is also possible to dispose them at a site where light transmission is required.

[Second Embodiment] Next, a second embodiment of the present invention will be described. In the embodiments described below, the conductive pattern 24 of the divided conductive film 22 and the gap 2
6 is the same as the first embodiment except for the shape of 6, and therefore, the same reference numerals are given to the respective portions and the description is omitted, and only the points different from the first embodiment will be described.

In the first embodiment described above, the divided conductive film 22 in which the width b of the conductive pattern 24 and the width d of the gap 26 are changed is used. However, as shown in FIG.
In the second embodiment, the width d of the gap 26 is fixed,
Divided conductive film 2 in which only width b of conductive pattern 24 is changed
2 is used.

In the second embodiment, two frequency bands f _{11 to} f ₁₂ and f _{21 to} f ₂₂ are defined as the frequency bands of the electromagnetic waves to be absorbed by the electromagnetic wave absorbing panel 10. f ₁₁ ~f ₁₂ width b corresponds to the b1 _min ~ b1 _max conductive pattern is changed in the range of 24
And A, the width b corresponds to the frequency band f ₂₁ ~f ₂₂ is b2 _min ~
The conductive patterns 24B changing in the range of b2 _max are alternately arranged.

More specifically, the width b of the conductive pattern 24A changes linearly from the maximum width b1 _max to the minimum width b1 _min along the longitudinal direction of the conductive pattern 24A, and then from the minimum width b1 _min to the maximum width b1 _max . It has a regular shape in which a change pattern that changes linearly is repeated at a constant cycle. Similarly, the conductive pattern 24B has a width b from the maximum width b2 _max to the minimum width b2 along the longitudinal direction of the conductive pattern 24B.
linearly to _min , followed by a minimum width b2 _min to a maximum width b2
_It has a regular shape in which a change pattern that changes linearly to _max is repeated at a constant cycle.

[0064] The conductive patterns 24A, 24B is set to the position where the width b of the conductive pattern 24A is in the maximum width b1 _max, the position where the width b of the conductive pattern 24B becomes the minimum width b2 _{m in} match And the width d of the gap 26 between adjacent conductive patterns is arranged to be constant. The change in the width b of the conductive patterns 24A and 24B may be non-linear.

Change range b1 of width b of conductive pattern 24A
_min ~ B1 _max is determined as follows based on the frequency f1 _min, f1 _{m ax.} That is, first electromagnetic radiation of a wavelength lambda ₁₁ divided by the four frequencies f _{11 (λ 11/4)} the resistive film 16
Permittivity ε to match the distance between
₁₁ (relative permittivity epsilon _S11), the electromagnetic wavelength lambda ₁₂ of frequency f ₁₂
Divided by the 4 (lambda _12/4) dielectric constant epsilon ₁₂ to match the distance between the resistive member and the reflecting member (relative permittivity epsilon _S12)
Are calculated based on the above equation (1). Then, based on the relative permittivity ε _S11 , the conductive pattern 2 is formed based on the above equation (2).
4 with obtaining the width b1 _min of, determine the width b1 _max of the conductive pattern 24 from the dielectric constant epsilon _S12. As a result, the variation range of the width b of the conductive pattern 24A for absorbing an electromagnetic wave of each frequency of the electromagnetic wave absorption band f ₁₁ ~f ₁₂ at a high absorption rate is obtained. The width b of the conductive pattern 24B
Of the change range b2 _{min to} b2 _max of the frequency f2 _min ,
It can be obtained in the same manner as described above based on f2 _max .

The operation of the second embodiment will be described. Book second
Also in the case of the electromagnetic wave absorbing panel 10 according to the embodiment, the arrangement direction of the conductive patterns 24 of the divided conductive film 22 (the width direction of the conductive patterns 24) is,
It is arranged in a direction substantially perpendicular to the direction of the plane of polarization of the electromagnetic wave arriving at the building and so that the electromagnetic wave arrives from the resistive film 16 side.

In the second embodiment, the conductive pattern 24A
The width b, regularly varied in accordance with the electromagnetic wave frequency band f ₁₁ ~f ₁₂ of to be absorbed changes range b1 _min ~b1 _max,
The width d of the conductive pattern 24B, since the regularly varied depending on the frequency band f ₂₁ ~f ₂₂ of the electromagnetic wave to be absorbed changes range b2 _min ~b2 _max, a primary injection waves E _r1 secondary injection The conductive pattern 24A is disposed at the center frequency of the frequency band in which the electromagnetic wave E _r2 is substantially in opposite phase (λ / 2) and the electromagnetic wave emitted from the electromagnetic wave absorbing panel 10 is largely attenuated and absorbed by canceling each other. In the region where the conductive pattern 24A is formed, f ₁₁ -f ₁₂
Continuously and periodically in the range of
In the portion B is disposed, will vary continuously and periodically in a range of f ₂₁ ~f ₂₂ along the longitudinal direction of the conductor pattern 24B.

Accordingly, the electromagnetic wave E ₀ arriving at the electromagnetic wave absorbing panel 10 (however, only the electromagnetic wave whose direction of the polarization plane is substantially perpendicular to the arrangement direction of the conductive patterns 24 of the divided conductive film 22)
Can be absorbed with a high absorptivity over the entire frequency bands f _{11 to} f ₁₂ and the frequency bands f _{21 to} f ₂₂ of the electromagnetic waves to be absorbed.

[Third Embodiment] Next, a third embodiment of the present invention will be described. As shown in FIG. 5, the divided conductive film 22 according to the third embodiment is configured by arranging a plurality of conductive patterns 24C having a substantially rectangular outer shape in a matrix with a gap 26 therebetween. The multiple conductive patterns 24C have the same shape as each other, and more specifically, are curved such that the middle portions of the four sides are each protruded outward from the conductive pattern 24C.

As a result, the conductive patterns 2 along the first arrangement direction (the direction of arrow A in FIG. 5) of the conductive patterns 24C are formed.
The width b1 of 4C is in the second arrangement direction (the direction of arrow B in FIG. 5).
Is the maximum width b1 _max at the center along the gradually toward both end portions along the second arrangement direction (the non-linear) becomes smaller, there is a minimum width b1 _min at the both end portions. Similarly,
The width b2 of the conductive pattern 24C along the second arrangement direction of the conductive pattern 24C is a maximum width b2 _max (= b1 _max ) at the center along the first arrangement direction, and is along the first arrangement direction. Gradually (non-linearly) smaller towards both ends,
The minimum width b2 _min (= b1 _min ) is set at both ends.

Each of the conductive patterns 24C arranged in the first arrangement direction has a width b1 which is the maximum width b1 _max and is located at the same position in the second arrangement direction. Since they are arranged, the width d1 of the gap 26 of each conductive pattern 24C arranged along the first arrangement direction
Also, along with the change of the width b1 of the conductive pattern 24C, the width changes nonlinearly along the second arrangement direction as the maximum width d1 _max → the minimum width d1 _min → the minimum width d1 _min . The conductive patterns 24C arranged in the second arrangement direction are arranged such that the portions where the width b2 is the maximum width b2 _max are located at the same position along the first arrangement direction. The conductive patterns 24C arranged in the second arrangement direction
The width d2 of the gap 26 is also the width b2 of the conductive pattern 24C.
Along with the maximum width d2 _max along the first arrangement direction.
It has been changed to the minimum width d2 _min → minimum width d2 _min and non-linear.
The width b1 and b2 of the conductive pattern 24C and the gap 2
The change in the widths d1 and d2 of line 6 may be linear (in this case, the outer shape of the conductive pattern 24 is an octagon).

[0072] In the third embodiment, based on the lowest frequency f ₁ and the maximum frequency f ₂ of the frequency band of the electromagnetic wave to be absorbed, the change range of the width b1 of the conductive patterns 24C b1 _min ~ B1
and _max a variation range d1 _min ~ D1 of (= change in the width b2 range b2 _min ~ B2 _max) and the width d1 of the gap 26 _max (= variation range d2 _min ~ D2 _max width d2) in the same manner as in the first embodiment It has established.

The operation of the third embodiment will be described. Book 3
In the electromagnetic wave absorption panel 10 according to the embodiment, the divided conductive films 22 in which the conductive patterns 24C are arranged in a matrix are provided. The pattern is arranged such that the electromagnetic wave simply arrives from the resistive film 16 side without associating the arrangement direction of the pattern 24C with the direction of the plane of polarization of the electromagnetic wave arriving at the building.

That is, the divided conductive material according to the third embodiment
The film 22 has conductive patterns 24C arranged in a matrix.
The resistance film 16 and the reflection film 18
The effective relative permittivity in the first arrangement direction between
Ε along the array direction_S1→ ε_S2→ ε_S1→… continuous and round
And between the resistance film 16 and the reflection film 18.
The effective relative permittivity in the second arrangement direction is
Along the direction ε_S1→ ε _S2→ ε_S1→… continuous and periodic
Has changed.

Accordingly, regardless of the direction of the plane of polarization of the electromagnetic wave arriving at the building (for example, any of horizontal polarization, vertical polarization and circular polarization), the electromagnetic wave emitted from the electromagnetic wave absorbing panel 10 can be used. The center frequency of the frequency band in which is greatly attenuated and absorbed changes continuously and periodically in the range of f _{1 to} f ₂ along the first arrangement direction and the second arrangement direction. Therefore, the electromagnetic wave E arriving at the electromagnetic wave absorbing panel 10
₀ can be absorbed with a high absorption rate over the entire frequency band f _{1 to} f ₂ of the electromagnetic wave to be absorbed, regardless of the direction of the polarization plane of the electromagnetic wave.

[Fourth Embodiment] Next, a fourth embodiment of the present invention will be described.
The state will be described. As shown in FIG. 6, the fourth embodiment
The divided conductive film 22 according to the second embodiment is similar to the third embodiment, and is similar to the third embodiment.
A large number of conductive patterns having a substantially rectangular shape have a gap 2
6 and are arranged in a matrix.
In the fourth embodiment, as in the second embodiment, the electromagnetic
Frequency band of electromagnetic wave to be absorbed by wave absorbing panel 10
As an area, f₁₁~ F₁₂And f_{twenty one}~ F_{twenty two}Two frequency bands
The divided conductive film according to the fourth embodiment has a defined area.
22 is a frequency band f₁₁~ F₁₂Conductivity corresponding to
Pattern 24D and frequency band f _{twenty one}~ F_{twenty two}Corresponding to
The electric patterns 24E are arranged alternately.
I have.

Similar to the conductive pattern 24C described in the third embodiment, the conductive pattern 24D is curved so that the middle portions of the four sides are each convex outside the conductive pattern 24D. Of the conductive pattern 24D along the first arrangement direction (the direction of arrow A in FIG. 6).
Has a maximum width b11 _max at the center along the second arrangement direction (the direction of the arrow B in FIG. 6), and gradually (nonlinearly) decreases toward both ends along the second arrangement direction. Both ends have a minimum width b11 _min . Similarly, the width b12 of the conductive pattern 24 along the second arrangement direction of the conductive pattern 24D is equal to the maximum width b12 at the center along the first arrangement direction.
_max (= b11 _max ), gradually (non-linearly) smaller toward both ends along the first arrangement direction, and has a minimum width b12 _min (= b11 _min ) at both ends.

On the other hand, the conductive pattern 24E is curved with the same curvature as the conductive pattern 24D so that the middle portions of the four sides are each convex toward the inside of the conductive pattern 24E. The width b21 of the conductive pattern 24E along the arrangement direction is a maximum width b21 _max at both ends along the second arrangement direction, and gradually (nonlinearly) toward the center along the second arrangement direction. It has a minimum width b21 _min at the center. Similarly, the width b22 of the conductive patterns 24 along the second arrangement direction of the conductive patterns 24E is the maximum width b22 at both ends along the first arrangement direction.
_max (= b21 _max ), gradually (nonlinearly) smaller toward the center along the first arrangement direction, and has a minimum width b22 _min (= b21 _min ) at the center.

The conductive patterns 24D and 24E arranged along the first arrangement direction have a width b11 in the conductive pattern 24D.
Where the width is the maximum width b11 _max and the conductive pattern 2
4E, the portions where the width b21 is the maximum width b21 _max are arranged so as to be located at the same position as each other along the second arrangement direction. The width d of the gap 26 of the patterns 24D and 24E is constant.

The conductive patterns 24D and 24E arranged in the second arrangement direction include a portion where the width b12 is the maximum width b12 _max in the conductive pattern 24D and a width b22 which is the maximum width b22 _max in the conductive pattern 24E. Are arranged so as to be located at the same position as each other in the first arrangement direction, so that the width d of the gap 26 between the conductive patterns 24D and 24E arranged in the second arrangement direction Is also constant.

[0081] In the fourth embodiment, the change in variation range b11 _min ~b11 _max (= width b12 of the conductive pattern 24D having a width b11 corresponding to the electromagnetic wave frequency band f ₁₁ ~f ₁₂ of to be absorbed range b12 _min to B12 the _max), the basis of the frequency f _1, f _{2 2}
It is determined in the same manner as in the embodiment. The conductive pattern 2 corresponding to the frequency band f ₂₁ ~f ₂₂ of the electromagnetic wave to be absorbed
4E variation range of the width b21 b21 _min ~b21 _max (= variation range b22 _min ~b22 _max width b22) of, are determined in the same manner as in the second embodiment based on the frequency f _1, f _2.

The operation of the fourth embodiment will be described. Book 4
The electromagnetic wave absorbing panel 10 according to the embodiment is provided with the divided conductive film 22 in which the conductive patterns 24D and 24E are arranged in a matrix. As in the case of the embodiment, it is arranged so that the electromagnetic wave simply arrives from the resistance film 16 side.

Further, the divided conductive film 2 according to the fourth embodiment
2 indicates that the conductive patterns 24D and 24E are
The resistive film 16 and the resistive film 16 are arranged alternately.
Effective relative dielectric with respect to the first arrangement direction between the film and the projection film 18
In the portion corresponding to the conductive pattern 24D,
Ε along the second array direction_S11→ ε_S12→ ε_S11And continuous
At the position corresponding to the conductive pattern 24E.
Ε along the second arrangement direction_S22(Frequency f_{twenty two}
Effective relative permittivity value corresponding to) → ε_S21(Frequency f _{twenty one}To
Corresponding effective relative permittivity value) → ε_S22And continuously changing
You.

On the other hand, the effective relative dielectric constant between the resistive film 16 and the reflective film 18 in the second arrangement direction is ε _S11 → along the first arrangement direction at a portion corresponding to the conductive pattern 24D. ε _S12 → ε _S11 continuously changes, and at a portion corresponding to the conductive pattern 24E, changes continuously along the first arrangement direction as ε _S22 → ε _S21 → ε _S22 .

Thus, regardless of the direction of the plane of polarization of the electromagnetic wave arriving at the building (for example, any of horizontal polarization, vertical polarization, and circular polarization), the electromagnetic wave emitted from the electromagnetic wave absorption panel 10 can be used. the center frequency of the frequency band to be greatly attenuated and absorbed, in the portion corresponding to the conductive pattern 24D along the first arrangement direction and the second arrangement direction, each successive range of f ₁₁ ~f ₁₂ To conductive pattern 2
4E, the first arrangement direction and the second
Along the arrangement direction of, and continuously changes in the range of f _{21 to} f ₂₂ . Therefore, the electromagnetic wave E ₀ arriving at the electromagnetic wave absorbing panel 10 can be converted into the frequency bands f _{11 to} f ₁₂ and the frequency band f _{11 of the} electromagnetic wave to be absorbed regardless of the direction of the polarization plane of the electromagnetic wave.
It can be absorbed by the high absorption over the entire ₂₁ ~f _22.

[Fifth Embodiment] Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, as a frequency band of electromagnetic waves to be absorbed by the electromagnetic wave absorbing panel 10, the center frequency is largely different two frequency bands (center frequency f ₁ of the frequency band and center frequency f ₂ of the frequency band) is defined and, dividing the conductive film 22 according to the fifth embodiment, a square conductive pattern 24F corresponding to the frequency band of the center frequency f _1, the conductive pattern 24G square corresponding to the frequency band of the center frequency f ₂ combined It is configured.

In the fifth embodiment, the conductive patterns 24F
The width (length of a side) b1, and determined based on the center frequency f ₁ of the corresponding frequency band, the width of the conductive pattern 24G (side length) of b2, corresponding frequency band center frequency f ₂ However, since the center frequencies f ₁ and f ₂ are greatly different, the length of the side of the conductive pattern 24F is slightly smaller than の of the length of the side of the conductive pattern 24G. ing. For this reason, the divided conductive film 22 according to the fifth embodiment has four gaps 26 with a constant width.
A conductive pattern group in which the individual conductive patterns 24F are arranged in a matrix and the conductive patterns 24G are arranged in a matrix and are alternately arranged.

The operation of the fifth embodiment will be described. Book 5
Since the electromagnetic wave absorbing panel 10 according to the embodiment is provided with the conductive pattern group in which the four conductive patterns 24F are combined and the divided conductive film 22 in which the conductive patterns 24G are arranged in a matrix, the windows of the building are provided. In the case of disposing the electromagnetic wave from the resistive film 16, the electromagnetic wave is simply arranged from the resistive film 16 side, as in the third and fourth embodiments.

In the fifth embodiment, the effective relative permittivity between the resistive film 16 and the reflective film 18 is different from that of the conductive pattern 24.
F, the first arrangement direction and the second arrangement direction
Is ε _{S1 in both} the arrangement direction and ε _S2 in the first arrangement direction and the second arrangement direction in the portion corresponding to the conductive pattern 24G.

Thus, regardless of the direction of the plane of polarization of the electromagnetic wave arriving at the building (for example, any of horizontal polarization, vertical polarization and circular polarization), the electromagnetic wave emitted from the electromagnetic wave absorbing panel 10 can be used. the center frequency of the frequency band is greatly attenuated and absorbed becomes f ₂ in portions corresponding to f _1, the conductive pattern 24E is at the site corresponding to the conductive pattern 24F. Therefore, among the electromagnetic waves E ₀ arriving at the electromagnetic wave absorbing panel 10, the electromagnetic waves in the frequency band of the center frequency f ₁ and the electromagnetic waves in the frequency band of the center frequency f ₂ are
Irrespective of the direction of the plane of polarization of the electromagnetic waves, they can be absorbed at a high absorption rate.

In the above description, parameters related to the relative permittivity (the width b of the conductor pattern 24 and the gap 26
The width of the electromagnetic wave absorption band has been widened by regularly changing the width d), but the present invention is not limited to this. Irregularly (randomly) the parameters related to the relative permittivity are changed. You may make it change.

In the above description, the width b of the conductor pattern 24
(Only the width of the conductor along the direction intersecting the direction in which the resistance member and the reflection member are arranged) is changed, or the width b and the width d of the gap 26 (along the direction intersecting the direction in which the resistance member and the reflection member are arranged). Although the mode in which the effective relative permittivity is changed by changing the gap between the conductors described above has been described, the present invention is not limited to this, and the film thickness a of the divided conductive film 22 (conductive pattern 24) (the resistance member and the reflection The effective relative permittivity may be changed by changing only the thickness of the conductor along the direction in which the members are arranged) or by changing the film thickness a in combination with the width b or the width d.

The electromagnetic wave absorber according to the present invention is not limited to being disposed in a window of a building. For example, the electromagnetic wave absorber may be buried in concrete or the like constituting a building (when buried in concrete, If there is a possibility that corrosion of the electromagnetic wave absorber may occur with time due to the substances present in the surroundings, the electromagnetic wave absorber may be buried after taking measures to prevent corrosion by coating the surface, etc., and construction members (for example, outer wall panels). , Inner wall panels, handrails, blinds, etc.).

For example, if an outer wall of a building is constructed by using an outer wall panel on which an electromagnetic wave absorber is disposed in advance, or if an electromagnetic wave absorber is buried in the outer wall at the time of construction of a building, electromagnetic waves come from outside. Thereby, electromagnetic waves re-radiated from the outer wall of the building can be reduced, and it is possible to prevent radio interference such as reception interference around the building from occurring.

If the inner wall of a building is constructed using an interior panel in which an electromagnetic wave absorber is disposed in advance, or if the electromagnetic wave absorber is buried in the inner wall during construction of the building, the electromagnetic wave is radiated inside the building. Even if a source is provided, leakage to the outside of the building can be reduced. In addition, if an electromagnetic wave absorber is provided on the wall surface, floor surface, and ceiling surface of a specific room in a building, leakage of electromagnetic waves from the specific room or intrusion of electromagnetic waves from the outside into the specific room Can be reduced, and the specific room can be used as a so-called anechoic chamber.

Further, the above-described electromagnetic wave absorbers may be multiplexed at at least a plurality of locations such as a grid, a screen, a window glass, a sash, a curtain, a blind, a partition or furniture installed in a room. For example, the electromagnetic wave absorption performance of multiple electromagnetic wave absorbers is integrated,
High electromagnetic wave absorption performance can be obtained.

In the construction work or the like, the above-described electromagnetic wave absorber is attached to a sheet material provided between an incoming electromagnetic wave and a worker, such as a curing sheet or a fall prevention net. You may. Thereby, the worker working in the region where the electric field strength of the incoming electromagnetic wave is high can be protected from the incoming electromagnetic wave.

Further, the electromagnetic wave absorber according to the present invention is not limited to application to construction members. If an electromagnetic wave absorber according to the present invention is attached to an object such as a tip of a wing of an aircraft such as a military aircraft that does not want to re-emit an incoming electromagnetic wave, the object is re-emitted from the object. Electromagnetic waves can be reduced.

In general, electromagnetic waves, though weak, are radiated from electric / electronic devices handling high-frequency currents or electric / electronic devices provided with an electromagnetic wave radiation source (devices equipped with a cathode ray tube, a microwave oven, etc.). . If such an electric / electronic device is provided with the electromagnetic wave absorber described above, the electromagnetic wave radiated from the electric / electronic device can be reduced, and the effect of the radiated electromagnetic wave on the human body can be reduced. Also, it is possible to reduce radio interference caused by radiated electromagnetic waves.

[0100]

As described above, according to the first aspect of the present invention, the frequency of the electromagnetic wave to be absorbed is set between the resistance member and the reflection member along the direction intersecting the direction in which the resistance member and the reflection member are arranged. Since the dielectric member in which the relative dielectric constant ε _S is changed regularly or irregularly according to the band is provided, an excellent effect that the band of the electromagnetic wave absorption band can be widened is realized.

According to a second aspect of the present invention, a plurality of conductors arranged at least along the direction intersecting the direction in which the resistance member and the reflection member are arranged are provided between the resistance member and the reflection member, and a plurality of conductors are provided between the resistance member and the reflection member. The width of the conductor along the direction intersecting the direction in which the resistance member and the reflection member are arranged, and the resistance member and the reflection member so that the effective relative permittivity changes regularly or irregularly according to the frequency band of the electromagnetic wave to be performed. Since at least one of the gap between the conductors along the direction intersecting with the direction in which the conductors are arranged and the thickness of the conductor along the direction in which the resistance member and the reflection member are arranged are changed regularly or irregularly, the direction of the plane of polarization is changed. Has an excellent effect that an absorption band of an electromagnetic wave substantially orthogonal to the first direction can be broadened.

According to a third aspect of the present invention, in the second aspect of the invention, the plurality of conductors are arranged at intervals along a first direction intersecting a direction in which the resistance member and the reflection member are arranged. At least one of the width and the gap of the conductor along the direction is changed regularly or irregularly, and the interval is set along the direction in which the resistance member and the reflection member are arranged and the second direction intersecting the first direction. Since the conductors are arranged at intervals and at least one of the width and the gap of the conductor along the second direction is changed regularly or irregularly, in addition to the above-described effects, regardless of the direction of the polarization plane of the electromagnetic wave, the electromagnetic wave absorption This has the effect that the band can be broadened.

According to a fourth aspect of the present invention, in the second aspect of the present invention, a plurality of conductors are formed on a substrate made of an insulating material. This has the effect that the distance can be made smaller.

According to a fifth aspect of the present invention, in the first or the second aspect of the present invention, the conductive film is formed on the substrate by adjusting the conductivity so that a part of the arriving electromagnetic wave is absorbed. Is included in the resistance member, and in addition to the above effects, there is an effect that electromagnetic waves emitted from the electromagnetic wave absorber can be further reduced.

According to a seventh aspect of the present invention, in the first aspect of the present invention, each member constituting the electromagnetic wave absorber is made substantially transparent. There is an effect that it becomes possible to apply such an electromagnetic wave absorber to a window of a building or the like.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an electromagnetic wave absorbing panel according to an embodiment.

FIG. 2 is a plan view showing a conductive pattern in the electromagnetic wave absorbing panel according to the first embodiment.

FIG. 3 is a conceptual diagram for explaining the principle of electromagnetic wave absorption by an electromagnetic wave absorbing panel.

FIG. 4 is a plan view showing a conductive pattern in an electromagnetic wave absorbing panel according to a second embodiment.

FIG. 5 is a plan view showing a conductive pattern in an electromagnetic wave absorbing panel according to a third embodiment.

FIG. 6 is a plan view showing a conductive pattern in an electromagnetic wave absorbing panel according to a fourth embodiment.

FIG. 7 is a plan view showing a conductive pattern in an electromagnetic wave absorbing panel according to a fifth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Electromagnetic wave absorption panel 16 Resistive film 18 Reflective film 22 Divided conductive film 24 Conductive pattern 26 Gap

 ──────────────────────────────────────────────────の Continued on the front page (71) Applicant 000001122 Hitachi Kokusai Electric Inc. 3- 14-20 Higashi-Nakano, Nakano-ku, Tokyo (72) Inventor Kenichi Harakawa 1-5-1, Otsuka, Inzai-shi, Chiba Pref. Takenaka Corporation Inside the Technical Research Institute of Construction Office (72) Inventor Nobuyoshi Murai 1-5-1, Otsuka, Inzai City, Chiba Prefecture Inside the Research Institute of Takenaka Corporation (72) Inventor Toshio Saito 1-5-1, Otsuka 1, Inzai City, Chiba Prefecture Stock Company (72) Inventor Motoyasu Togashi 1-1-11-11 Shiba, Minato-ku, Tokyo Nippon Sheet Glass Environmental Amenities Inc. (72) Inventor Yasushi Hoshino 1-11-1-11 Shiba, Minato-ku, Tokyo Japan Sheet Glass Environment Amenity Co., Ltd. (72) Inventor Yoshiaki Matsuo 1406 Hasunuma, Omiya City, Saitama Prefecture Yagi Antenna Yagi Antenna Co., Ltd. Omiya Plant (72) Invention Person Atsushi Minase 1406 Hasunuma, Omiya City, Saitama Prefecture Yagi Antenna, Omiya Plant Co., Ltd. FA14 FA31 FA32 GA06 GA12 GA24 GA32 GA42 HA11 HB01 HD11 HD13 2E039 AC00 5E321 AA43 AA44 GG05

Claims (7)

[Claims] A resistance member that reflects a part of the arriving electromagnetic wave and transmits another part; a reflection member that is arranged at a distance from the resistance member and reflects the arriving electromagnetic wave; A dielectric constant ε is provided between the reflection member and a direction along the direction intersecting the direction in which the resistance member and the reflection member are arranged, according to the frequency band of the electromagnetic wave to be absorbed.
_An electromagnetic wave absorber comprising: a dielectric member in which _S is changed regularly or irregularly. 2. A resistance member that reflects a part of the arriving electromagnetic wave and transmits another part, a reflection member that is arranged at a distance from the resistance member and reflects the arriving electromagnetic wave, A plurality of conductors provided between the reflection member and arranged at intervals along a direction intersecting a direction in which the resistance member and the reflection member are arranged. The plurality of conductors, the width of the conductor along the intersecting direction, the intersection so that the effective relative permittivity changes regularly or irregularly according to the frequency band of the electromagnetic wave to be absorbed An electromagnetic wave absorber wherein at least one of a gap between the conductors along a direction and a thickness of the conductors along the direction in which the conductors are arranged is changed regularly or irregularly. 3. The plurality of conductors are arranged at intervals along a first direction intersecting a direction in which the resistance member and the reflection member are arranged, and the first conductor is arranged in accordance with a frequency band of an electromagnetic wave to be absorbed. At least one of the width and the gap of the conductor along the first direction is regularly or irregularly changed so that the effective relative permittivity in the direction changes regularly or irregularly, It is arranged at intervals along the second direction intersecting the first direction and the line-up direction, and the effective relative permittivity in the second direction is regular according to the frequency band of the electromagnetic wave to be absorbed. The electromagnetic wave absorber according to claim 2, wherein at least one of the width and the gap of the conductor along the second direction is changed regularly or irregularly so as to change irregularly. body. 4. The electromagnetic wave absorber according to claim 2, wherein said plurality of conductors are formed on a substrate made of an insulating material. 5. The resistance member includes a substrate made of an insulating material, and a conductive film formed on the substrate with a conductivity adjusted to absorb a part of an incoming electromagnetic wave. The electromagnetic wave absorber according to claim 1, wherein the electromagnetic wave absorber comprises: 6. The reflection member according to claim 1, wherein the reflection member includes a substrate made of an insulating material, and a conductive film formed on the substrate. Electromagnetic wave absorber. 7. The electromagnetic wave absorber according to claim 1, wherein each member constituting the electromagnetic wave absorber is substantially transparent.