WO2010119863A1

WO2010119863A1 - Wave absorber

Info

Publication number: WO2010119863A1
Application number: PCT/JP2010/056585
Authority: WO
Inventors: 石塚一男; 海渕住男; 江口友和
Original assignee: 株式会社リケン; 株式会社リケン環境システム
Priority date: 2009-04-14
Filing date: 2010-04-13
Publication date: 2010-10-21
Also published as: TW201130192A; JPWO2010119863A1; TWI442629B; JP5460697B2

Abstract

Disclosed is a compact wave absorber for effectively absorbing radio waves in a frequency band from 30 MHz to 18 GHz. A magnetic loss absorber (4) is configured from a plurality of magnetic loss bodies (3) having a polygonal pyramid shape or a wedge shape and arranged on the same plane. A dielectric loss absorber (6) is configured from platy dielectric loss bodies (5) arranged perpendicularly or obliquely to the plane in adjoining valley parts with the narrow width portion positioned as the root portion. A wave absorber (1) is configured from the magnetic loss absorber (4) and the dielectric loss absorber (6). The dielectric loss absorber (6) can be configured so that, for example, two inclined platy loss bodies are inclined at an angle in the range from over 0° to 45°, with respect to a plane perpendicular to the plane, and thereby the cross-section has an approximately V shape. It is preferable that the dielectric loss absorber (6) has a grid shape surrounding each of the magnetic loss bodies (3) arranged in a matrix and having a polygonal pyramid shape or a wedge shape.

Description

Radio wave absorber

The present invention relates to a radio wave absorber, and more particularly to a small radio wave absorber that effectively absorbs electromagnetic waves in a frequency band of 30 MHz to 18 GHz.

In recent years, electronic devices are compatible with the electromagnetic environment (EMC) so that the electromagnetic interference generated by the electronic device does not cause other devices to malfunction, and conversely, the electronic device does not malfunction due to external electromagnetic interference. Electro Magnetic Compatibility) is demanded. In order to perform EMC evaluation, a measurement room called an anechoic chamber is required. The outer wall of the anechoic chamber is covered with a metal plate in order to prevent the entry of external electromagnetic waves into the dark room and the radiation of electromagnetic waves generated from the measuring device in the dark room to the outside. In order to prevent unnecessary reflection of electromagnetic waves, a radio wave absorber is attached to the inside of the dark room. The types of anechoic chambers include a 10 m method anechoic chamber for evaluating large products such as automobiles and large electronic devices, a 3 m method anechoic chamber for evaluating relatively small products, and a small dark room. In a 3 m dark room and a small dark room, it is particularly required that the radio wave absorber is small.
Conventionally, the frequency range measured in an anechoic chamber was 30 MHz to 1 GHz. However, with the downsizing and diversification of communication devices such as mobile phones and RF tags, the upper limit of measurement frequency is increasing. In February 2007, a method for confirming a measurement site in the frequency range of 1 GHz to 18 GHz was announced by CISPR16-1-4 Ed. The corresponding frequency range required for the anechoic chamber is expanded to 30 MHz to 18 GHz.

Generally, as a radio wave absorber for adapting to a broadband frequency, a composite wave absorber combining a pyramid-shaped radio wave absorber containing carbon and a ferrite tile is used. In such a composite wave absorber, electromagnetic waves in a frequency band of 300 MHz or higher are absorbed by a pyramid-shaped wave absorber, and electromagnetic waves in a frequency band lower than that are absorbed by a ferrite tile. As a result, radio wave absorption characteristics can be secured in a wide frequency band of 30 MHz to 18 GHz. However, since the height of the composite electromagnetic wave absorber is generally 90 cm to 300 cm, a 3 m anechoic chamber or a small anechoic chamber using the same cannot be designed in a space-saving manner.

In Patent Document 1, as a radio wave absorber for a small dark room, a ferrite tile and a pyramid-shaped absorber made of a material in which ferrite powder is dispersed in a general-purpose resin having a predetermined relative dielectric constant bonded thereto. A composite electromagnetic wave absorber is disclosed. It is described that it is possible to cope with high frequencies by using this radio wave absorber for a conventional small ferrite darkroom size. However, in the magnetic characteristics of ferrite, there is a limit to increasing the frequency due to the snake limit. For this reason, it is considered difficult to cope with a frequency band of 10 GHz or more even if the composition of ferrite is optimized.

On the other hand, Patent Document 2 discloses a radio wave absorber formed of a radio wave absorber formed of a conductive resistive film body and arranged in a lattice shape or a honeycomb shape in a vertical direction toward a metal plate. Yes. In this radio wave absorber, the surface resistance value of the resistance film body is set as a free space radio wave impedance, and is arranged in a lattice shape or the like with a constant interval and a constant thickness. For this reason, it is said that reflection of the radio wave incident on the absorber surface can be suppressed. In addition, the radio waves that have traveled inside the resistance coating body are attenuated by absorbing the radio waves on the resistance coating body surface, and the impedance near the surface of the metal plate approaches the impedance of the space. Is described as being possible. In this radio wave absorber, the height of the absorber necessary for matching the impedance to the spatial impedance can be greatly reduced, which is advantageous in terms of space. However, the radio wave absorber disclosed in Patent Document 2 composed of a dielectric loss body can effectively absorb radio waves in a high frequency band, but cannot cope with radio waves in a low frequency band.

Japanese Patent No. 3041295 Japanese Patent No. 2660647

The present invention has been made in view of the above circumstances, and an object thereof is to provide a small radio wave absorber that effectively absorbs electromagnetic waves in a wide frequency band from 30 MHz to 18 GHz.

As a result of diligent research in view of the above object, the inventors of the present invention have found that a polygonal pyramid-shaped or wedge-shaped magnetic lossy body between adjacent polygonal pyramids or a valley between wedges is perpendicular to the bottom surface of the magnetic lossy body, Alternatively, by providing an inclined plate-like dielectric loss body, it is possible to greatly improve the radio wave absorption characteristics in the high frequency band while maintaining the radio wave absorption characteristics in the low frequency band. The inventors have found that excellent radio wave absorption characteristics can be obtained and have arrived at the present invention. That is, the radio wave absorber of the present invention is a magnetic loss absorber composed of a plurality of polygonal pyramid-shaped or wedge-shaped magnetic loss bodies, and the bottom surface of the magnetic loss body is spaced apart from each other at a predetermined interval on a plane. A magnetic loss absorber comprising a plate-like dielectric loss body, and a valley portion between the magnetic loss bodies based on a narrow width portion. And a dielectric loss absorber disposed perpendicular to the bottom surface of the magnetic loss body or inclined at a predetermined angle.

According to the present invention, a small wave absorber having excellent wave absorption performance in a wide frequency band is realized. By using this, measurement in a wide frequency band is possible even in a 3 m method anechoic chamber or a small anechoic chamber.

The radio wave absorber of the present invention will be described in detail below.
In the description of the radio wave absorber in this specification (including claims), unless otherwise specified, the radio wave absorber of the present invention defines the direction with reference to the state where the radio wave incident side is disposed on the upper side, For example, the cross-sectional view will be described as a cross section perpendicular to the plane in which the cross section is arranged (the bottom surface of the radio wave absorber). Since these electromagnetic wave absorbers are attached to the floor surface, wall surface, and ceiling surface when attached to the electromagnetic wave anechoic chamber, it goes without saying that the posture can be taken either vertically or horizontally.
Further, in the drawings attached to the present specification, reference numerals are not attached to all members, but may be given to only some of the representative components, and other similar parts may be omitted. is there.

FIG. 1 shows a cross-sectional view of an example of the radio wave absorber of the present invention. A radio wave absorber 1 shown in FIG. 1 includes a magnetic loss absorber 4 composed of a plurality of pyramidal magnetic loss bodies 3 placed on a flat plate portion 2 with a bottom surface and spaced apart by a predetermined distance. The dielectric loss absorber 6 is composed of a plate-like dielectric loss body 5 disposed in a valley formed between the pyramidal magnetic loss bodies 3. That is, a valley portion is formed between adjacent pyramids by placing the bottom surface of the magnetic loss body 3 on the same plane at a predetermined interval. A plate-like dielectric loss body 5 is installed in the valley portion perpendicular to the bottom surface of the magnetic loss body 3 (upper surface of the flat plate portion 2) with a narrow width portion as a base.
The material of the flat plate portion 2 is not particularly limited as long as the upper surface is flat, but resin, rubber, wood, ceramics and the like are used. Further, by using the material of the flat plate portion 2 as a magnetic loss material, further excellent radio wave absorption characteristics can be obtained. The flat plate portion 2 may be formed as a separate member from the magnetic loss body 3, but when it is made of the same material as the magnetic loss body 3 placed thereon, it is integrally formed by injection molding or the like. This is preferable from the viewpoint of manufacturing cost.

As shown in the propagation path 7, a part of the electromagnetic wave incident on the radio wave absorber 1 having the above configuration is repeatedly reflected between the dielectric loss body 5 and the magnetic loss body 3, while the dielectric loss body 5 and the magnetic loss body. 3 is absorbed and decays. Further, as indicated by the propagation path 8, the electromagnetic wave transmitted through the dielectric loss body 5 is absorbed and attenuated while being repeatedly reflected between the magnetic loss bodies 3. As described above, in the radio wave absorber 1 of the present invention, an optimum reflection path is formed for the electromagnetic waves of the respective frequencies, and the electromagnetic waves are absorbed and attenuated, so that the electromagnetic waves in a wide frequency band can be effectively absorbed.

The magnetic loss body 3 may be a polygonal pyramid shape (including a conical shape) or a wedge shape, but a quadrangular pyramid shape or wedge shape magnetic loss body 3 having a square bottom surface is preferably used. At this time, the length of one side of the bottom surface of the quadrangular pyramid of the magnetic loss body 3 is preferably 10 mm to 200 mm. In the present invention, the specific height (dimension from the bottom surface to the top) of the magnetic loss body 3 is not particularly limited, but is preferably 50 mm to 200 mm in order to realize a small dark room or the like. The tip of the magnetic loss body 3 may have an acute angle, but in consideration of impact resistance, it is preferably a curved surface (R shape) or a flat surface. In the present invention, the “bottom surface of the magnetic loss body” is a surface where the polygon appears as a plane (a surface opposite to the tip of the cone) in the case of a polygonal cone shape, and in the case of a wedge shape. The surface located on the opposite side of the wedge tip will be referred to.

The material of the magnetic loss body 3 is not particularly limited, and examples thereof include resins and ceramics containing ferrite powder. As the ferrite powder, Fe ₂ O ₃ / NiO / ZnO system, Fe ₂ O ₃ / NiO / ZnO / CuO system, Fe ₂ O ₃ / MnO / ZnO system, or the like is used. As the resin material, polyethylene, polypropylene, fluorine resin, allyl resin, epoxy resin, vinyl chloride resin, vinyl acetate resin, styrene resin, acrylic resin, polyamide resin, polyacetal resin, polycarbonate resin, acetyl cellulose resin, etc. are used. . Any one of these resin materials may be used, but a plurality of them may be mixed and used. As the ceramic material, alumina, silica, mullite, or the like is used. The content of the ferrite powder is preferably 37% by mass to 91% by mass with respect to the total mass of the magnetic loss body.

In the present invention, the magnetic loss absorber 4 is configured by placing a plurality of magnetic loss bodies 3 on a flat surface (flat plate portion 2) with the bottom surface thereof placed. Here, the magnetic loss bodies may be arranged at a predetermined interval, but the bottom surfaces of adjacent magnetic loss bodies may be arranged adjacent (closely). Thereby, the valley part which installs a plate-shaped dielectric loss body between magnetic loss bodies is formed. In the case of a polygonal-pyramidal magnetic loss body, it is preferable that the magnetic loss absorber is configured by arranging the magnetic loss bodies in a regular matrix form, for example. In the case of a wedge-shaped magnetic loss body, a plurality of magnetic loss bodies are arranged in parallel to form one block, and a plurality of blocks arranged in different directions, such as a vertical direction, are installed at adjacent locations. A magnetic loss absorber may be configured.

The dielectric loss body 5 is a general plate-like member, and has a wide width portion constituting the main surface and a narrow width portion which is a side surface connecting the front and back main surfaces. With this narrow portion as a base, it is installed perpendicularly or at a predetermined angle with respect to the bottom surface (installation plane) of the magnetic loss body 3. When the dielectric loss body is provided with an inclination, it is preferable to make the inclination in a range of greater than 0 degree and not more than 45 degrees with respect to the vertical plane. Further, as an example of the embodiment, a dielectric loss absorber is configured by combining a vertical plate-like dielectric loss body and an inclined plate-like dielectric loss body or two inclined plate-like dielectric loss bodies per one valley. You can also When the two dielectric loss bodies are tilted, each can take the tilt angle. That is, when two plate-like dielectric loss bodies are adjacent to each other and have a V-shaped cross section, the two plate-like dielectric loss bodies are larger than 0 degrees in the opposite directions with respect to the vertical plane, It is preferable to incline within a range of 45 degrees or less. By constructing a dielectric loss absorber by disposing a plate-like dielectric loss body in this range, reflection in the incident direction is suppressed and reflection between dielectric loss bodies increases, so that the radio wave absorber is excellent. It can have radio wave absorption characteristics. In addition, when two plate-like dielectric loss bodies are combined per one valley portion, the narrow portion which becomes the base portion or the top portion may be continuous, for example, a combination having a V-shaped cross section. May be.
The dielectric loss body is installed for the purpose of improving the radio wave absorption performance in a frequency band of 10 GHz or more, which is the absorption limit of the magnetic loss body. Therefore, the horizontal spacing between the dielectric loss bodies is as large as the target minimum frequency of 10 GHz, that is, 0.5 to 2.0 times the wavelength of 3.0 cm. It is preferably set to 5 cm to 6 cm. When the plate-like dielectric loss bodies are installed at an inclination, it is preferable to set the horizontal distance at the maximum height of adjacent dielectric loss bodies within the above range.

As long as the dielectric loss body is a plate-like material made of a dielectric loss material, its material and structure are not particularly limited. For example, as the structure, a sheet-like single plate material, or a plate material structure including a cardboard structure or a honeycomb structure can be applied. Dielectric loss materials include carbon-containing foamed urethane, carbon-containing foamed styrene, carbon-containing foamed polypropylene, or plastic containing carbon or coated with a carbon layer, paper, sheets made of inorganic materials such as silica and alumina, etc. It is done. As the carbon, powdered carbon such as carbon fiber, graphite, and carbon black is used. When carbon fibers are used, the fiber length is preferably 0.5 mm to 7 mm, and the fiber diameter is preferably 5 μm to 10 μm. The amount of carbon fiber added is preferably 0.03% by mass to 1.7% by mass and more preferably 0.03% by mass to 0.4% by mass with respect to the total mass of the dielectric loss body. When graphite is used as the carbon powder, the particle size of the powder is preferably 1 μm to 100 μm, and it is preferable to add 1.5% by mass to 15% by mass with respect to the total mass of the dielectric loss body. On the other hand, when carbon black is used, the primary particle size of the powder is preferably 10 nm to 500 nm, and is preferably added in an amount of 1% by mass to 5% by mass with respect to the total mass of the dielectric loss body.

Hereinafter, the radio wave absorber 1 of the present invention will be described with reference to the drawings, focusing on the form of the dielectric loss absorber 6 of the present invention.
FIG. 2 shows a perspective view of a dielectric loss absorber 6 having a plurality of wedge shapes formed from a plate-like dielectric loss body 5. When the dielectric loss absorber 6 having this configuration is used, a plate-like dielectric loss body 5 having a substantially V-shaped cross section is installed in a continuous valley portion between adjacent polygonal pyramid or wedge-shaped magnetic loss bodies 3 to thereby absorb the radio wave absorber. 1 is constituted. In this configuration, the reflection path between the dielectric loss body 5 and the magnetic loss body 3 becomes more complicated than the

propagation paths

7 and 8 shown in FIG. For this reason, the radio wave absorber 1 constituted by these can reliably absorb electromagnetic waves in a wide frequency band. Here, the two plate-like dielectric loss bodies 5 constituting the V shape of the dielectric loss absorber 6 are inclined in the range of more than 0 degree and less than 45 degrees toward the opposite side with respect to the vertical plane. It is preferable to do so.

The height of the dielectric loss absorber 6 (the distance from the highest plane farthest from the arrangement plane, that is, the length of the perpendicular line from the highest section to the arrangement plane) is a polygonal pyramid shape or a wedge shape. The ratio when the height of the magnetic loss body 3 is 100 is preferably 50 to 200, more preferably 70 to 130. By setting the height of the dielectric loss absorber 6 within this range, the radio wave absorption characteristics of the radio wave absorber 1 are further increased by the electromagnetic wave confinement effect due to the space surrounded by the magnetic loss body 3 and the dielectric loss body 5. improves.
Note that the dielectric loss absorber of this configuration may have the same height in the entire region, but the height may be changed depending on the location, for example, one height of the V shape is increased and the other is decreased. it can. In this case, it is preferable that the arithmetic average height of the dielectric loss absorber falls within the above range.

FIG. 3 is a perspective view of another wedge-shaped dielectric loss body 5 (dielectric loss absorber 6). In this example, the upper surface portion (vertex portion) of the wedge-shaped dielectric loss body 5 in FIG. 2 is partially cut and opened, and each vertex of the polygonal pyramid-shaped or wedge-shaped magnetic loss body 3 is exposed from the opening 9. It was made possible (the exposure state is not shown). This configuration is preferable in that reflection in the incident direction on the upper surface portion of the dielectric loss body 5 is suppressed, and thus more excellent radio wave absorption characteristics can be obtained by reflection between the dielectric loss bodies 5.

4A shows a plate-like dielectric loss body 5 (dielectric loss absorber 6) having a substantially V-shaped cross section (fin shape) extending in one direction, and FIG. 4B shows a pyramidal magnetic loss. The structure of the radio wave absorber 1 in which the plate-like dielectric loss body 5 is installed only in one direction of the adjacent valley portion of the body 3 is shown. In this configuration, the plate-like dielectric loss absorber 6 does not have a horizontal plane with respect to the bottom surface of the pyramidal magnetic loss body 3. For this reason, reflection in the electromagnetic wave incident direction is suppressed, and more excellent radio wave absorption characteristics can be exhibited.

Furthermore, this modification is shown in FIG. Here, the radio wave absorber 1 is configured by using the radio wave absorber shown in FIG. 4B as a basic configuration and arranging the plurality of the wave absorbers so that the extending directions of the fins are different from each other. This radio wave absorber 1 has no directionality of its radio wave absorption characteristics and can efficiently absorb electromagnetic waves in all directions.

6 (A) to 6 (C) show a radio wave absorber 1 according to another embodiment of the present invention. In the present embodiment, the dielectric loss absorber 6 includes a plurality of dielectric loss bodies 5 having a substantially V-shaped cross section provided with a notch on the lower side shown in FIG. 6A, and FIG. 6B. A plurality of dielectric loss bodies 5 each having a substantially V-shaped cross section provided with a notch on the upper side, and by fitting these together, a grid-shaped dielectric loss absorber 6 is obtained. On the other hand, a plurality of pyramidal magnetic loss bodies 3 are arranged in a matrix to form a magnetic loss absorber 4. The radio wave absorber 1 is configured by arranging the grid-shaped dielectric loss absorber 6 in a valley portion of the pyramid-shaped magnetic loss body 3 so as to cover the dielectric loss absorber 6 from above. At this time, the notch portion of the dielectric loss body 5 is designed to have a size matched to the vertical and horizontal rows so as to fit a valley portion formed by arranging a plurality of pyramidal magnetic loss bodies 3 adjacent to each other. Has been. Such a grid-shaped dielectric loss absorber 6 further increases the number of reflections of electromagnetic waves and produces an excellent confinement effect. Therefore, the radio wave absorption characteristics of the radio wave absorber 1 are greatly improved.

FIG. 7 shows a radio wave absorber 1 in which plate-like dielectric loss bodies 5 having a substantially V-shaped cross section are installed on the side surfaces of all the pyramidal magnetic loss bodies 3. In this configuration, the number of reflections of electromagnetic waves is further increased, and more excellent radio wave absorption characteristics are exhibited.

The effects of the present invention will be described in more detail with reference to the following examples.
Example 1
80% by mass was dispersed in a polypropylene resin with respect to a magnetic loss material from which Mn-based ferrite powder was obtained. A plurality of magnetic loss bodies 3 having a pyramid shape (bottom surface: 50 mm × 50 mm, height: 70 mm) were produced by injection molding this resin material. Then, as shown in FIG. 6C, on the flat plate portion 2 (thickness 13 mm) made of the same material as that of the magnetic loss body 3, four pyramid-shaped magnetic loss bodies 3 are arranged vertically and horizontally (16 in total) in a matrix form. The magnetic loss absorber 4 was obtained.
On the other hand, dielectric loss bodies 5 having the shapes shown in FIGS. 6 (A) and 6 (B) are respectively produced using a sheet of 3 mm thickness in which carbon fibers (fiber length: 3 mm, fiber diameter: 7 μm) are dispersed in paper. did. Here, the carbon fiber content was adjusted so that the dielectric constant of the dielectric loss body was 8 + j0.7. The notched portions of the respective dielectric loss bodies 5 were fitted together to form a grid-shaped dielectric loss absorber 6. The dielectric loss absorber 6 was disposed in the valley so as to cover the pyramidal magnetic loss body 3 from above, and the radio wave absorber 1 shown in FIG. The height of the grid-shaped dielectric loss body 5 was 52 mm and 0.74 times the height of the pyramid-shaped magnetic loss body 3.
FIG. 8 shows the results of measuring the radio wave absorption characteristics of the obtained radio wave absorber 1 from 10 GHz to 18 GHz. The measurement is performed by using a reflection amount measuring apparatus using a dielectric lens, using a sample having a bottom area of 600 mm × 600 mm, in which magnetic loss absorbers each having four pyramid-shaped magnetic loss elements arranged vertically and horizontally are arranged in three pieces vertically and horizontally. went. As a comparison, the measurement results of only the magnetic loss absorber 4 (Comparative Example 1) and the measurement results of only the dielectric loss absorber 6 (Comparative Example 2) are also shown in FIG.

In the magnetic loss absorber 4 of Comparative Example 1 alone, sufficient radio wave absorption characteristics could not be obtained in a high frequency band of 10 GHz or higher. Moreover, although only the dielectric loss absorber 6 of the comparative example 2 has a slightly improved frequency band compared to the comparative example 1 (magnetic loss absorber 4), it was not sufficient. On the other hand, in the radio wave absorber 1 according to the first embodiment of the present invention in which the magnetic loss absorber 4 and the dielectric loss absorber 6 are combined, the radio wave absorption performance (reflection loss) particularly in a high frequency band is greatly improved. It was confirmed that a return loss of 20 dB or more can be obtained in the entire frequency band of 10 GHz to 18 GHz. Although not shown in FIG. 8, in the radio wave absorber 1 of the present example, almost no decrease in radio wave absorption characteristics was observed even in the frequency range of 30 MHz to 10 GHz, and a return loss of 20 dB or more was obtained. .

Thus, according to the present invention, it is possible to significantly improve the radio wave absorption characteristics in the high frequency band while maintaining the excellent radio wave absorption characteristics of the magnetic loss material in the low frequency band. In this embodiment, it is considered that not only the interaction between the pyramid-shaped magnetic loss body and the grid-shaped dielectric loss body, but also the electromagnetic wave confinement effect due to the grid shape greatly contributes to the improvement of the radio wave absorption characteristics.

It is sectional drawing which shows an example of the electromagnetic wave absorber of this invention. It is a perspective view which shows an example of a plate-shaped dielectric loss body (dielectric loss absorber). It is a perspective view which shows another example of a plate-shaped dielectric loss body (dielectric loss absorber). It is the perspective view (A) which shows another example of a plate-shaped dielectric loss body (dielectric loss absorber), and the perspective view (B) of the electromagnetic wave absorber of this invention using the same. It is a perspective view which shows another example of the electromagnetic wave absorber of this invention. It is a perspective view ((A), (B)) which shows the dielectric loss body which comprises a grid-shaped dielectric loss absorber, and a perspective view (C) of the electromagnetic wave absorber of this invention using the same. It is a perspective view which shows another example of the electromagnetic wave absorber of this invention. It is a figure which shows the result of having evaluated the electromagnetic wave absorption characteristic of the electromagnetic wave absorber of Example 1, the comparative example 1 (magnetic loss absorber only), and the comparative example 2 (dielectric loss absorber only).

DESCRIPTION OF SYMBOLS 1 ... Radio wave absorber 2 ... Flat plate part 3 ... Pyramid magnetic loss body 4 ... Magnetic loss absorber 5 ... Plate-like dielectric loss body 6 ... Dielectric loss absorber 7 ... -Propagation path 8 ... propagation path 9 ... opening

Claims

A magnetic loss absorber comprising a plurality of polygonal pyramid-shaped or wedge-shaped magnetic loss bodies, wherein the bottom surface of the magnetic loss body is placed adjacent to or spaced apart from each other on a plane between the magnetic loss bodies. A magnetic loss absorber provided with a valley,
A dielectric loss absorber composed of a plate-like dielectric loss body, which is arranged at a valley portion between the magnetic loss bodies with a narrow width portion as a base, and is inclined at a predetermined angle or perpendicular to the bottom surface of the magnetic loss body. A dielectric loss absorber,
An electromagnetic wave absorber comprising:
The height of the dielectric loss absorber in the vertical direction from the plane is such that the ratio of the height of the magnetic loss body in the vertical direction from the plane to 100 is in the range of 50 to 200. Item 2. An electromagnetic wave absorber according to Item 1.
The dielectric loss absorber has a substantially V-shaped cross section, and at least one plate-like dielectric loss body constituting the V shape is inclined in a range of more than 0 degree and 45 degrees with respect to a vertical plane of the plane. The radio wave absorber according to claim 1 or 2, characterized in that.
4. The radio wave absorber according to claim 1, wherein the magnetic loss bodies are arranged in a matrix, and the dielectric loss absorber has a grid shape surrounding the magnetic loss bodies.
5. The radio wave absorber according to claim 1, wherein the magnetic loss body has a quadrangular pyramid shape.