Multifunctional electromagnetic wave absorber

IPC classes for russian patent Multifunctional electromagnetic wave absorber (RU 2510951):

H01Q17/00 - Devices for absorbing waves radiated from an aerial; Combinations of such devices with active aerial elements or systems

Another patents in same IPC classes:

Method of making bulk microwave energy absorbers / 2510926

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Electromagnetic wave absorber and radar absorbent material for production thereof / 2500704

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Radar-absorbing material / 2482149

Invention relates to a radar-absorbing material. The radar-absorbing material consists of a polymer binder, filler in the form of a mixture of powdered ferrite, and carbonyl iron with the spherical particles diameter of 10-50 microns and a mixture of fullerenes C-60 and C-70. The radar-absorbing material additionally comprises carbon nanotubes in the form of multilayer straightened nanotubes with the diameter of 10 nm to 0.1 microns and the length of 10-100 microns.

Layered protective material / 2474628

Fibrous absorber of electromagnetic radiation comprises two inner layers of a mixture of dielectric and electrically conducting carbon fibers which are mechanically fastened to each other by needling. Manufacturing of the absorber is carried out from the mixture of dielectric and electrically conducting carbon fibers, in which carbon fiber is used as electrically conducting carbon fibers. Carbon fiber is used with specific insulation resistance from 1.5·10^-3 to 1.0 Ohm cm, and the deviation from the average value of content of carbon fiber in 1 g of the mixture does not exceed 5% by weight. The absorber additionally comprises two outer layers of rubberised fabric. The absorber has the structure of the inner layers of a mixture of dielectric and electrically conducting carbon fibers fixed by piercing with needles with a density of piercing from above of 5÷20 cm^-2, from below of 20÷100 cm^-2. The absorber layers are made of rubberised fabric, on the edges they are tightly stuck to each other or connected by double-faced adhesive tape.

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/ 2271058

FIELD: radio engineering, communication.

SUBSTANCE: electromagnetic wave absorber for anechoic chambers and shielded rooms, having a spike-shaped hollow low-combustible housing made of single-face laminate, in the inner cavity of which there is a radar-absorbent filler, characterised by that the housing has the shape of a rectangular prism, wherein the ratio of sides which form a right angle to the thickness of the prism is equal to 6(±1):3(±0.5):1.

EFFECT: high efficiency of shielding.

3 dwg, 1 tbl

Proposed by the authors, the invention relates to the fields of antenna technology, integrated protection from electromagnetic fields and can be used to create absorbers of electromagnetic waves (sew)used in the equipment anechoic chambers (BACK) and shielded rooms (EP).

Sew represent structures, devices, designs of the specified materials (as a rule, stealth), has a specific pattern of changes in the dielectric and magnetic properties, which ensures efficient absorption of electromagnetic energy in the desired frequency range with a slight reflection.

When creating a multi function BACK are wide sew, usually thorn design, electrical losses, which are in good agreement with the free space and have high radio performance. Known to sew, made using polyurethane foam with carbon filler (Metzmacher M., Morgounov VA "Anechoic chamber microwave); Radio and communication, 1982). Despite its small weight characteristics and low coefficient of reflection, they have serious disadvantages, which will be removed through the use of hull structures sew.

For example, in a known patent USSR No. 1755720 from 30.03.1989, the above option is izgotovlenie pyramidal sew, the case of which the inner filler made of fire-resistant of penisbest filled with carbon fiber. However, the low strength characteristics and carcinogenic properties of the material from which made PSUs are serious disadvantages of this solution.

With the development of integrated protection of technological measures and humans from exposure to electromagnetic fields are shielded space, the inner surface of which, in recent years, faced a variety of radar absorbing materials or absorbers of electromagnetic waves. This is done with the goal of overall reduction of electromagnetic field inside the object, eliminate standing waves and resonance phenomena at frequencies comparable with the linear dimensions of the internal volume of space. For example, in the RF patent for useful model №82371 from 13.08.2008, listed building material made of two components: the base, which is made on the basis of the woven metal mesh, and a shielding layer using magnesium-schungite plasters "ALFAPOL". This material is very effective to create a protective surfaces and has a shielding rate of more than 60 dB in a wide frequency range. However, it has the disadvantage inherent in all high the conductive materials great reflection coefficient of the electromagnetic field, having a value of more than 25%, which is absorbed in confined spaces, mainly the staff.

The closest in technical essence and the achieved result to the claimed technical solution (prototype) is the absorber of electromagnetic wave anechoic chambers and shielded rooms containing thorn hollow combustible enclosure mikrogofrakartona, in the inner cavity of which stealth is a placeholder representing a three-dimensional, flat shape, strip, or ribbon, made of fire-resistant sheet of conductive material on a base of paper or fabric with an electric resistance of from 100 to 1000 Ω/□ (RF patent No. 2340054 from 17.10.2007,). The disadvantage of this absorber should include a greater height (thickness) of the product, which is to obtain a small reflection coefficient should be commensurate with the length of the incident electromagnetic wave, which when fully facing working surfaces shielded areas significantly reduce its effective area.

The task was to develop a multifunctional sew, while maintaining a small reflection coefficient in the microwave range of small weight, high strength and fireproof characteristics could the be used for broadband equipment anechoic chambers, and as a facing radar absorbing material for shielded rooms.

The technical result from the use of the invention consists in the extension of the scope, improving manufacturability, and maintainability of the proposed absorber of electromagnetic waves.

The technical result is achieved in that in a known absorber of electromagnetic wave anechoic chambers and shielded rooms containing thorn hollow combustible enclosure mikrogofrakartona, in the inner cavity of which is radio-absorbing filler, according to the invention the hollow body has a shape of a rectangular prism, the ratio of the sides forming a right angle and thickness of the prism is the magnitude 6(±1):3(±0,5):1.

The present applicant search patent and scientific and technical sources and selected from the list of analogues of the prototype revealed distinctive features in the claimed solution, therefore, the proposed solution meets the criteria of the invention "novelty". Additional search conducted by the applicant have not found technical solutions that have similar characteristics with the features distinguishing the claimed solution to the prototype.

1 shows a General view of the technical solutions claimed sew, where 1 is a hollow body with radiopage is the missing placeholder; 2 - mount sew to the surface of the BACKING; 3 - mount sew to the surfaces of the electronic signature.

Figure 2 shows variants a) and b) facing the claimed sew surfaces of the BACK.

Figure 3 shows the options C) and d) facing the claimed sew surfaces of the electronic signature.

The case of the proposed absorber is made of mikrogofrakartona, which achieves the mechanical strength of the product. To add properties to the materials that are classified as low-cut blanks are initially treated with a solution of the flame retardant composition, dried and then formed into the shape of the absorber and glued it in a special industrial equipment.

Stealth is a placeholder that is positioned inside the housing sew, can be different for technological production, for example, from a sheet of paper or fabric conductive material is performed using sizegripenabled compositions with an electric resistance of from 100 to 1000 Ω/□ or on the basis of spherical granules of foamed polystyrene or foamed glass with a diameter of from 1.0 to 10.0 mm, covered with the conductive film with the same electrical resistance.

The specified resistance range is optimal for the material of the filler, because these values are dependent reflection coefficients and absorbed what I electromagnetic waves have the most rational values.

After the vibration filling of the filler in the inner volume of the shell sew with a density of 60 kg/m³last airtight seal, and then on the outer surface of the absorber mount fasteners required to facing surfaces of the BACK or EP. The attachment points can be made in the form of metal "whiskers", which sink and put it on rails, fixed on the surface of the premises, or in the form of textile fasteners, second part which is attached to any surfaces in the specified location. In shielded rooms facing radar absorbing material is also possible with the use of water-resistant adhesive compositions.

The versatility of the proposed technical solution is that it can be used as in an anechoic chamber designed to simulate free space, and as a facing material in shielded rooms where maximum absorption of the radiated fields. However, depending on specified amounts of living space and essential radio characteristics BACK and VC, claimed sew can have different ways of facing working surfaces, shown in figure 2 and Figure 3.

As an example of the proposed technical solution for the wedge sew thickness of 50 mm with Lin is inimi sizes of legs 150 mm and 300 mm and a weight of 0.8 kg in the table below, thicknesses and electronic characteristics of the different use cases of the absorber, and to compare the characteristics of the prototype.

Table
Use case	Thickness, mm	The reflection coefficient of the power %	The absorption coefficient for the light, dB
Frequency, GHz	Frequency, GHz
0,6	1,0	2,0	5,0	10,0	0,6	1,0	2,0	5,0	10,0
For BUCK Option a) Option b)	300	2,0	0,4	0,1	0,02	0,01	-	-	-	-	-
150	6,0	1,0	0,3	0,2	0,1	-	-	-	-	-
For EP Option C) Option d)	50 150	-	13,5	10,5	8,0	6,3	9,5	13,8	of 17.5	21,0	27,0
-	to 12.0	9,8	8,0	6,3	28,5	41,4	52,5	63,0	81,0
The placeholder	300	1,0	0,3	0,04	0,02	0,01	-	-	-	-	-

As can be seen from the table, the claimed sew has a PR is one use case is very small values of reflection coefficient, which is commensurate with the prototype. In another variation, use as a cladding material, has a significant absorbing properties, which is difficult to obtain for thorn prototype. It should be noted here that in the presence of the screen in a screened room provides values for the absorption coefficient is doubled, since the electromagnetic wave is reflected from the screen is absorbed by the material with the same coefficient of absorption.

Different variants of the inventive absorber allow you to get on their basis spaces for various purposes. For example, when using sew (Option a) you can create a BUCK, which is measured fundamental parameters of antennas, scattering characteristics of radar targets, aligning dynamical systems, etc. In an anechoic chamber equipped with sew (Option b), it is possible to conduct tests of radio systems, measuring equipment, elements of communication and to create the premises for the radio control serial production.

For shielded rooms the use of the claimed sew (Option) it is imperative to ensure favourable environmental conditions and biological protection of personnel against high level of unauthorized electromagnetic who etnich radiation within the object of various equipment and electrical equipment.

When solving problems of electromagnetic safety of premises not having shielded surfaces and volumes in terms of protection of commercial information, the use of the claimed sew (Option d) is very relevant and appropriate, since such cladding has a greater potential for complete elimination of leakage channels.

The claimed technical solution is fireproof, environmentally friendly sew, which during operation emits no harmful or toxic substances, has a simplified manufacturing techniques and simple manufacturing operations at facing surfaces of the BACK or EP, which is reduced in hanging or bonding wedge-shaped elements or in the laying of the facing walls of the stacked pairs of absorbing wedges like masonry.

Technical appraisal and economic benefits claimed sew consist in the fact that it is based upon a single item and low cost products, using only different ways of facing areas, it is possible to find an optimal and cost effective solutions to the many challenges faced by developers is very expensive facilities such as anechoic chambers and shielded rooms.

The absorber of electromagnetic wave anechoic chambers and shielded rooms containing thorn hollow Trutnov Ruchi case of mikrogofrakartona, in the inner cavity of which is radio-absorbing filler, characterized in that the housing has the shape of a rectangular prism, the ratio forming a right angle sides and the thickness of the prism is the magnitude 6(±1):3(±0,5):1.