Device for absorption of electromagnetic radiation

 

(57) Abstract:

Device for absorption of electromagnetic radiation consists of a ferrite substrate and the applied matching dielectric layer with carbon filler, which is a layered structure consisting of flat layers of sound-absorbing material of different density, and the density of the layers decreases with distance from the ferrite substrate. As the absorbent material may be used inorganic, non-combustible material, for example foamed basalt. Matching dielectric layers can be made with different content of carbon filler, the carbon content of the filler in the dielectric layers is within 0,0610-4- 0,3610-4about.h. The technical result is to create a broadband absorber for electromagnetic anechoic chambers in the frequency range 20 - 30000 MHz, having sound absorbing properties and does not require the use of complex technologies in its manufacture. 4 C.p. f-crystals, 2 tab., 1 Il.

The invention relates to the field of radio, namely absorbers for electromagnetic anechoic chambers, a device for absorption of electromagnetic waves, containing a hollow conical section, the walls of which are made of resin with the addition of carbon. The lower part of the conical section connected to the cylindrical base, inside of which is perpendicular to the axis of the cone at a certain distance from one another are flat layers of carbon-containing resin. The thickness of these layers speed increases as the distance from the conical section, resulting in an average conductivity region in the cylindrical base also increases with distance from the cone [1].

The disadvantages of this device: the lack of absorption in the low frequency range, sophisticated manufacturing technology and a sufficiently large thickness of the absorber.

It is known device, which is broadband absorber of electromagnetic radiation. The absorber contains a metal plate, which is a ferrite plate. On the surface of the ferrite plate has multiple separated by intervals of conical elements of ferrite or composite ferrite-based [2].

The disadvantages of this device are: great weight, not wide enough frequency range and tekhnologicheskovo to absorb electromagnetic radiation, adopted as a prototype used to cover the walls of anechoic chambers, a thin, solid, pyramid-shaped, filled with carbon filler absorber. Its operating range is within from 30 MHz to 30 GHz. The device consists of a ferrite substrate and the matching layer pyramidal shape. Depending on the required frequency range of the height of the pyramid is 12, 18, 30 and 40 inches. Ferrite substrate consists of individual tiles with an area of 100 x 100 mm, which is attached to the metal surface. Matching pyramidal part consists of a separate absorbing elements [3].

The drawbacks are the necessity of using special manufacturing techniques matching layer pyramidal complex forms of material of constant density, the absence of sound-absorbing properties, which is necessary when testing electrical equipment, accompanied by noise, harmful bezdeystvuyushiye on staff.

An object of the invention is the creation of a broadband absorber for electromagnetic anechoic chambers is effective in the frequency range from 20 to 30,000 MHz with sound absorbing its the th problem the proposed device for the absorption of electromagnetic radiation, consisting of a ferrite substrate and the applied matching dielectric layer with carbon filler, representing a layered structure consisting of flat layers of sound-absorbing material of different density, and the density of the layers decreases with distance from the ferrite substrate. Matching dielectric layers made with different content of carbon filler, which is in the range from 0,0610-4to 0,3610-4parts by volume. As a sound absorbing material used inorganic non-combustible material, for example foamed basalt.

Change pyramidal matching layer absorber prototype on the uniform greatly facilitates the manufacturing technology of the claimed device, and the presence of several layers of foam basalt different density and different content carburized fiber allows at least the thickness of the device to receive radio characteristics similar to the characteristics of the absorber prototype in the same range. But the inventive absorber has a lower weight, thinner in the same frequency range. Weight 1 m2the current prototype is on basalt in the inventive absorber with a total thickness of 15.7 cm equal 6,14 kg

The absorber is a ferrite layer thickness of 65 mm and a layered dielectric structure consisting of 5 layers of foam basalt different density, monotonically decreasing from the ferrite layer.

In table. 1 presents characteristics of the foamed layers of basalt. The numbering of the layers starts from the ferrite substrate.

Comparative parameters are presented in table. 2.

The drawing shows the dependence of the reflection coefficient (dB) frequency (MHz) of the proposed absorber and prototype.

From the drawing it is seen that in the frequency range from 100 to 700 MHz proposed absorber has a level of reflection about 5 dB larger than the prototype, but in the shortwave range (2000 to 10000 MHz) proposed a more efficient absorber of the prototype is approximately 5 to 10 dB, and in the rest of the band features reflect almost the same.

From table. 2 and the drawing shows that when the same radio characteristics and operating frequency range of the inventive absorber is almost two times less weight and thickness. In addition, the inventive absorber has sound-absorbing properties, which is of great importance to protect obsluhoval for electromagnetic anechoic chambers effective in the range from 20 to 30,000 MHz and has sound-absorbing properties.

Literature

1. Patent 0370421 A1, EP, 1989

2. Patent 5617095, USA, publ. 1997

3. The company's catalog "Emerson & Cuming, USA, absorber ECCOSORB VHY, 1998, http://www.emersoncumingmp.com/catalog/anechoic/VHY.htm.

1. Device for absorption of electromagnetic radiation consisting of a ferrite substrate and the applied matching dielectric layer with carbon filler, characterized in that the matching of the dielectric layer is a layered structure consisting of flat layers of sound-absorbing material of different density, and the density of the layers decreases with distance from the ferrite substrate.

2. The device under item 1, characterized in that as the sound-absorbing material use of inorganic, non-combustible material.

3. The device under item 1 or 2, characterized in that the sound-absorbing material used foam basalt.

4. Device according to any one of paragraphs.1-3, characterized in that the matching dielectric layers made with different content of carbon filler.

5. Device according to any one of paragraphs.1-4, characterized in that the carbon content of the filler in the dielectric layers is in the pre

 

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The camera // 2103771
The invention relates to a device for testing the electromagnetic compatibility of electronic dei priori, for studies on the effects of electromagnetic fields on living organisms, for calibration of electromagnetic field sensors and represents THE chamber containing the external pyramidal closed conductor in the immediate vicinity of the installed base load combination, made of absorbing panel high frequency absorbers and ohmic resistances, and asymmetrically located inner conductor made of a conductive sheet, rolling in the field of load in a flat plate of less width passing through the absorbent panel and connected to the ohmic resistance, in this case, the top of the pyramid has agreed a move to connect the signal generator, wherein the inner conductor is made in the form of part of the lateral surface of a cone with a radius of cross-section R, defined by the ratio:

R = (0,25oC 0,3)(A + B)

where:

A and B are respectively the width and height of the cross-section of the outer conductor of THE camera, B = (0,7oC0,1)

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