FR2928779A1 - MATERIAL ABSORBING ELECTROMAGNETIC WAVES AND STRUCTURE USING SUCH MATERIAL - Google Patents
MATERIAL ABSORBING ELECTROMAGNETIC WAVES AND STRUCTURE USING SUCH MATERIAL Download PDFInfo
- Publication number
- FR2928779A1 FR2928779A1 FR8912514A FR8912514A FR2928779A1 FR 2928779 A1 FR2928779 A1 FR 2928779A1 FR 8912514 A FR8912514 A FR 8912514A FR 8912514 A FR8912514 A FR 8912514A FR 2928779 A1 FR2928779 A1 FR 2928779A1
- Authority
- FR
- France
- Prior art keywords
- mixture
- polyethylene
- electromagnetic waves
- epdm
- volume
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000000463 material Substances 0.000 title claims abstract description 20
- 239000000203 mixture Substances 0.000 claims abstract description 23
- 239000004698 Polyethylene Substances 0.000 claims abstract description 18
- -1 polyethylene Polymers 0.000 claims abstract description 18
- 229920000573 polyethylene Polymers 0.000 claims abstract description 18
- 229920002943 EPDM rubber Polymers 0.000 claims abstract description 15
- 229920000767 polyaniline Polymers 0.000 claims abstract description 15
- 229920001940 conductive polymer Polymers 0.000 claims abstract description 5
- 238000010521 absorption reaction Methods 0.000 claims abstract description 4
- 230000002745 absorbent Effects 0.000 claims description 15
- 239000002250 absorbent Substances 0.000 claims description 15
- 239000002245 particle Substances 0.000 claims description 8
- 239000002184 metal Substances 0.000 claims description 3
- 238000000227 grinding Methods 0.000 claims description 2
- 239000000047 product Substances 0.000 description 9
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 7
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N Aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 description 6
- 239000000843 powder Substances 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- FWLHAQYOFMQTHQ-UHFFFAOYSA-N 2-N-[8-[[8-(4-aminoanilino)-10-phenylphenazin-10-ium-2-yl]amino]-10-phenylphenazin-10-ium-2-yl]-8-N,10-diphenylphenazin-10-ium-2,8-diamine hydroxy-oxido-dioxochromium Chemical compound O[Cr]([O-])(=O)=O.O[Cr]([O-])(=O)=O.O[Cr]([O-])(=O)=O.Nc1ccc(Nc2ccc3nc4ccc(Nc5ccc6nc7ccc(Nc8ccc9nc%10ccc(Nc%11ccccc%11)cc%10[n+](-c%10ccccc%10)c9c8)cc7[n+](-c7ccccc7)c6c5)cc4[n+](-c4ccccc4)c3c2)cc1 FWLHAQYOFMQTHQ-UHFFFAOYSA-N 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000012153 distilled water Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 description 1
- 239000012935 ammoniumperoxodisulfate Substances 0.000 description 1
- HFACYLZERDEVSX-UHFFFAOYSA-N benzidine Chemical compound C1=CC(N)=CC=C1C1=CC=C(N)C=C1 HFACYLZERDEVSX-UHFFFAOYSA-N 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000000539 dimer Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- HQQADJVZYDDRJT-UHFFFAOYSA-N ethene;prop-1-ene Chemical group C=C.CC=C HQQADJVZYDDRJT-UHFFFAOYSA-N 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000000741 silica gel Substances 0.000 description 1
- 229910002027 silica gel Inorganic materials 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/04—Homopolymers or copolymers of ethene
- C08L23/06—Polyethene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/04—Homopolymers or copolymers of ethene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/16—Elastomeric ethene-propene or ethene-propene-diene copolymers, e.g. EPR and EPDM rubbers
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L79/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen or carbon only, not provided for in groups C08L61/00 - C08L77/00
- C08L79/02—Polyamines
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q17/00—Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
Abstract
L'invention concerne un matériau absorbant les ondes électromagnétiques.Elle a pour objet un matériau à base de polymère conducteur pour l'absorption d'ondes électromagnétiques, caractérisé en ce qu'il est constitué d'un mélange de 10 à 30 % en volume de polyaniline conductrice et de 70 à 90% en volome d'un mélange de polyéthylène et d'EPDM.Application à la réalisation d'une structure absorbant les ondes électromagnétiques recouvrant l'objet à protéger.The invention relates to a material that absorbs electromagnetic waves. It relates to a material based on conductive polymer for the absorption of electromagnetic waves, characterized in that it consists of a mixture of 10 to 30% by volume. of conductive polyaniline and 70 to 90 vol% of a mixture of polyethylene and EPDM.Application to the realization of a structure absorbing electromagnetic waves covering the object to be protected.
Description
10 15 20 25 30 35 MATERIAU ABSORBANT DES ONDES ELECTROMAGNETIQUES ET STRUCTURE UTILISANT UN TEL MATERIAU La présente invention concerne un matériau absorbant les ondes électromagnétiques et en particulier les ondes de fréquence comprise entre 8 et 12 Gigahertz (bande X). L'invention a également pour objet la réalisation d'une structure absorbante utilisant un tel matériau. On connaît des structures absorbantes du type ferrites qui ont le défaut d'être très lourdes, de l'ordre de 6 à 7 kg/m2. Cette forte densité n'est pas admissible dans la plupart des applications aéronautiques et spatiales ( avions furtifs, suppression des interférences dans les émissions de satellites), où la plus grande légèreté est recherchée. Il a été suggéré, en particulier par A. FELDBLUM dans J. POLY. SCI. 19 (1981) 173, de rechercher, dans le domaine des polymères conducteurs, moins denses que les ferrites, un matériau susceptible de présenter des possibilités d'absorption des ondes électromagnétiques. Mais, à ce jour, malgré plusieurs travaux intéressants, aucun matériau absorbant n'a été défini avec précision et en particulier, aucune structure utilisable n'a été décrite, à notre connaissance, dans les brevets. Un but de la présente invention est de définir une composition à base de polymère conducteur absorbante des rayonnements électromagnétiques, en particulier dans le domaine de la bande X. Un autre but de l'invention est de définir un procédé de mise en oeuvre du produit en particulier pour la réalisation de structures en forme de plaques légères, un objectif étant par exemple d'atteindre une fourchette de 1 à 2 kg/m2. L'invention a pour objet un matériau à base de polymère conducteur pour l'absorption d'ondes électromagnétiques, caractérisé en ce qu'il est constitué d'un mélange de 10 à 30 % en volume de polyaniline 10 15 20 25 30 2928779 -2 conductrice et de 70 à 90 % en volume d'un mélange de polyéthylène et d'EPDM. The present invention relates to a material absorbing electromagnetic waves and in particular to frequency waves of between 8 and 12 Gigahertz (X-band). The invention also relates to the production of an absorbent structure using such a material. Absorbent structures of the ferrite type are known which have the defect of being very heavy, of the order of 6 to 7 kg / m 2. This high density is not acceptable in most aeronautical and space applications (stealth aircraft, suppression of interference in satellite emissions), where the greatest lightness is sought. It has been suggested, in particular by A. FELDBLUM in J. POLY. SCI. 19 (1981) 173, to find, in the field of conductive polymers, less dense than ferrites, a material likely to have possibilities of absorption of electromagnetic waves. But, to date, despite several interesting work, no absorbent material has been defined with precision and in particular, no usable structure has been described, to our knowledge, in the patents. An object of the present invention is to define a composition based on electromagnetic radiation-absorbing conductive polymer, in particular in the X-band domain. Another object of the invention is to define a process for using the product in accordance with the invention. particularly for the production of structures in the form of lightweight plates, an objective being for example to reach a range of 1 to 2 kg / m2. The subject of the invention is a conductive polymer material for the absorption of electromagnetic waves, characterized in that it consists of a mixture of 10 to 30% by volume of polyaniline. 2 and 70 to 90% by volume of a mixture of polyethylene and EPDM.
Avantageusement, la proportion de polyéthylène dans le mélange polyéthylène/EPDM est comprise entre 60 et 95 % en volume. Advantageously, the proportion of polyethylene in the polyethylene / EPDM mixture is between 60 and 95% by volume.
De préférence, le matériau est réalisé sous forme de plaque à partir d'un mélange de polyaniline conductrice de granulométrie moyenne comprise entre 3 et 10 microns et de polyéthylène/EPDM ayant une granulométrie moyenne après broyage inférieure à 100 microns, le mélange ayant été effectué au turbula, le mélange étant chauffé à une température voisine de 200 degrés Celsius puis comprimée à une pression voisine de 200 à 300 bars. Preferably, the material is made in plate form from a conductive polyaniline mixture having a mean particle size of between 3 and 10 microns and polyethylene / EPDM having an average particle size after grinding of less than 100 microns, the mixture having been carried out turbula, the mixture being heated to a temperature of about 200 degrees Celsius and then compressed to a pressure of about 200 to 300 bar.
Une structure absorbante est réalisée en plaçant successivement, sur la pièce métallique à protéger des ondes électromagnétiques, 1 à 2 feuilles d'épaisseur voisine de 0,5 mm d'un matériau ayant des propriétés diélectriques voisines de celles du mélange polyéthylène/EPDM à 60-95 % en volume de polyéthylène, et 1 couche d'épaisseur voisine de 1,5 mm du matériau absorbant de l'invention. An absorbent structure is produced by successively placing, on the metal part to be protected from electromagnetic waves, 1 to 2 sheets of thickness close to 0.5 mm of a material having dielectric properties close to those of the 60% polyethylene / EPDM blend. -95% by volume of polyethylene, and 1 layer of thickness close to 1.5 mm of the absorbent material of the invention.
L'invention est précisée par les explications données ci-après relatives à l'élaboration du matériau de l'invention et à la réalisation d'un mode préféré de sa mise en oeuvre dans une structure absorbante. On se référera au dessin annexé dans lequel: The invention is specified by the explanations given below relating to the preparation of the material of the invention and to the realization of a preferred embodiment of its implementation in an absorbent structure. Reference is made to the appended drawing in which:
- la figure 1 est un diagramme de la granulométrie du noir d'aniline obtenu après la première étape de fabrication de la polyaniline, FIG. 1 is a diagram of the particle size of the aniline black obtained after the first step of manufacturing the polyaniline,
- la figure 2 est une vue partielle en coupe transversale d'une structure absorbante selon un premier mode de réalisation de l'invention, FIG. 2 is a partial cross-sectional view of an absorbent structure according to a first embodiment of the invention,
- la figure 3 est une vue en coupe transversale d'une structure absorbante selon une variante, 35 5 15 20 25 30 35 2928779 -3 Selon une caractéristique de l'invention, le matériau absorbant contient de la polyaniline, dont un mode d'obtention connu est rappelé ci-après. Dans un bac de 50 litres, on introduit 15,5 litres d'eau distillée, 5 litres d'acide chlorhydrique concentré (37%), puis lentement 1,5 litres d'aniline. Le mélange est refroidi aux environs de - 5°C. On oxyde l'aniline par introduction de peroxodisulfate d'ammonium (NH4)2 S2 08, soit encore 3,75 kg dans 9 litres d'eau. L'addition est faite lentement de sorte que le temps total de réaction soit voisin de 15 heures. Cette réaction produit un précipité de noir d'aniline dont la distribution granulométrique est typiquement concentrée sur 5 microns (Voir la figure 1 dans laquelle d désigne le diamètre des particules de noir d'aniline). Ce noir d'aniline se présente sous forme de sel, en poudre. Cette poudre est successivement lavée avec de l'eau distillée, puis avec des solutions d'acide chlorhydrique entre 2 et 4 M. Cette poudre est ensuite essorée, puis séchée sous azote avec pour traitement complémentaire un stockage de longue durée ( environ 15 jours) en présence de silica-gel. Le produit se présente alors sous forme de chlorhydrate. Le rendement de la réaction excède 80%. On peut avantageusement faire subir au produit obtenu un traitement supplémentaire afin de supprimer les dernières traces de benzidine formée au cours de la réaction. Il consiste en un rinçage à l'eau suivi d'une neutralisation par l'ammoniac et d'une extraction en phase vapeur au moyen d'alcool. Le produit obtenu est alors constitué de polyaniline neutre connue aussi sous le nom de polyéméraldine. FIG. 3 is a cross-sectional view of an absorbent structure according to a variant. According to a characteristic of the invention, the absorbent material contains polyaniline, a mode of which known obtaining is recalled below. In a 50 liter tank, 15.5 liters of distilled water, 5 liters of concentrated hydrochloric acid (37%) and then 1.5 liters of aniline are introduced slowly. The mixture is cooled to about -5 ° C. The aniline is oxidized by introduction of ammonium peroxodisulfate (NH 4) 2 S 2 O 8, that is to say another 3.75 kg in 9 liters of water. The addition is done slowly so that the total reaction time is around 15 hours. This reaction produces an aniline black precipitate whose particle size distribution is typically concentrated to 5 microns (See Figure 1 where d denotes the diameter of the aniline black particles). This black aniline is in the form of salt, powder. This powder is successively washed with distilled water, then with solutions of hydrochloric acid between 2 and 4 M. This powder is then drained, then dried under nitrogen with additional treatment for long-term storage (about 15 days) in the presence of silica gel. The product is then in the form of hydrochloride. The yield of the reaction exceeds 80%. The product obtained can advantageously be subjected to additional treatment in order to remove the last traces of benzidine formed during the reaction. It consists of a water rinse followed by neutralization with ammonia and a vapor phase extraction with alcohol. The product obtained is then composed of neutral polyaniline also known as polyemeraldine.
Pour rendre conductrice cette polyaniline, elle est "dopée", par exemple par lavage à l'acide chlorhydrique, suivi d'un séchage. To render this polyaniline conductive, it is "doped", for example by washing with hydrochloric acid, followed by drying.
Pour constituer le matériau absorbant de l'invention, on réalise un mélange de polyéthylène et 5 10 20 25 30 35 -4 d'EPDM, dimère de base éthylène-propylène. On choisit une proportion de 60 à 95 % en volume, de préférence 80%, de polyéthylène et par suite, de 40 à 5 % en volume d'EPDM. On broie ce mélange de manière à obtenir une poudre de granulométrie inférieure à 100 microns. Le mélange polyéthylène-EPDM est alors mélangé à la polyaniline dans une proportion de 15 à 30 % en volume de polyaniline. Le processus de mélange est choisi de manière à obtenir les valeurs des coefficients diélectriques les meilleurs pour les applications considérées, soit permittivité importante, fortes pertes diélectriques, etc.. La Demanderesse a observé que la meilleure technique de mélange est d'utiliser un mélange au turbula. Le mélange des poudres étant effectué, on place le produit dans un moule par exemple circulaire et comprenant deux plateaux; on chauffe l'ensemble à une température voisine de 2000C. Une pression de l'ordre de 200 bars est appliquée pendant 3 minutes; on refroidit alors le produit en appliquant une pression de l'ordre de 300 bars. On obtient ainsi typiquement une plaque de 250 millimètres de diamètre et de 1,5 millimètres d'épaisseur. Le produit est bien plus léger que les produits connus puisqu'il n'atteint que 1 à 2 kg par mètre carré. Les figures 2 et 3 illustrent deux modes de réalisation d'une structure absorbante mettant en oeuvre le produit précité. La figure 2 est une vue en coupe par un plan normal à la surface métallique 10 à protéger. On place sur cette surface deux feuilles 11 et 12 de polyéthylène/EPDM tel que défini plus haut, chacune ayant une épaisseur comprise entre 0,1 et 1 millimètre; on peut remplacer le polyéthylène/EPDM par tout matériau ayant des propriétés diélectriques voisines. La structure absorbante est complétée par une couche de polyaniline dopée telle que 10 15 20 -5 2928779 To form the absorbent material of the invention, a mixture of polyethylene and EPDM, an ethylene-propylene base dimer, is made. A proportion of 60 to 95% by volume, preferably 80%, of polyethylene and hence 40 to 5% by volume of EPDM is chosen. This mixture is ground so as to obtain a powder of particle size less than 100 microns. The polyethylene-EPDM mixture is then mixed with the polyaniline in a proportion of 15 to 30% by volume of polyaniline. The mixing process is chosen in such a way as to obtain the values of the dielectric coefficients that are the best for the applications under consideration, namely high permittivity, high dielectric losses, etc. The Applicant has observed that the best mixing technique is to use a mixture at the same time. turbula. The mixture of the powders being carried out, the product is placed in a mold for example circular and comprising two trays; the whole is heated to a temperature of 2000C. A pressure of the order of 200 bar is applied for 3 minutes; the product is then cooled by applying a pressure of the order of 300 bars. A plate 250 millimeters in diameter and 1.5 millimeters thick is thus typically obtained. The product is much lighter than the known products since it reaches only 1 to 2 kg per square meter. Figures 2 and 3 illustrate two embodiments of an absorbent structure employing the aforementioned product. Figure 2 is a sectional view through a plane normal to the metal surface 10 to be protected. Two sheets 11 and 12 of polyethylene / EPDM as defined above, each having a thickness of between 0.1 and 1 millimeter, are placed on this surface; polyethylene / EPDM can be replaced by any material having similar dielectric properties. The absorbent structure is completed by a doped polyaniline layer such as
définie plus haut, d'épaisseur comprise entre 1 et 2 millimètres. La figure 3 est une variante de réalisation qui ne comporte qu'une seule feuille de polyéthylène/EPDM ou équivalent. Une structure comme celles illustrées dans les figures 1 et 2 est particulièrement efficace pour absorber les ondes électromagnétiques OEM qui tombent normalement à la surface. La figure 4 est un diagramme qui montre les variations du coefficient de réflexion CR (en dB) en fonction de la fréquence f (en GHz) de l'onde électromagnétique reçue normalement à la structure, pour une structure de l'art antérieur ( courbe AA) et pour une structure selon l'invention (courbe INV). On voit que les résultats sont aussi bons pour la structure de l'invention qui, par ailleurs, est environ trois fois moins dense que celle de l'art antérieur. L'invention s'applique à la réalisation de structures absorbantes des ondes électromagnétiques, en particulier dans les domaines de l'aéronautique et de l'espace. 25 30 35 5 15 20 25 defined above, of thickness between 1 and 2 millimeters. Figure 3 is an alternative embodiment which comprises a single sheet of polyethylene / EPDM or equivalent. A structure such as those illustrated in FIGS. 1 and 2 is particularly effective at absorbing OEM electromagnetic waves that normally fall to the surface. FIG. 4 is a diagram which shows the variations of the reflection coefficient CR (in dB) as a function of the frequency f (in GHz) of the electromagnetic wave normally received at the structure, for a structure of the prior art (curve AA) and for a structure according to the invention (INV curve). It can be seen that the results are also good for the structure of the invention which, moreover, is about three times less dense than that of the prior art. The invention applies to the production of absorbent structures of electromagnetic waves, in particular in the fields of aeronautics and space. 25 30 35 5 15 20 25
Claims (4)
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8912514A FR2928779A1 (en) | 1989-09-25 | 1989-09-25 | MATERIAL ABSORBING ELECTROMAGNETIC WAVES AND STRUCTURE USING SUCH MATERIAL |
| GB9020779A GB2444759B (en) | 1989-09-25 | 1990-09-24 | Material absorbing electromagnetic waves and structure using such a material |
| DE4030170A DE4030170A1 (en) | 1989-09-25 | 1990-09-24 | Electromagnetic wave absorbing material and structure using such material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8912514A FR2928779A1 (en) | 1989-09-25 | 1989-09-25 | MATERIAL ABSORBING ELECTROMAGNETIC WAVES AND STRUCTURE USING SUCH MATERIAL |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| FR2928779A1 true FR2928779A1 (en) | 2009-09-18 |
Family
ID=39145003
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| FR8912514A Withdrawn FR2928779A1 (en) | 1989-09-25 | 1989-09-25 | MATERIAL ABSORBING ELECTROMAGNETIC WAVES AND STRUCTURE USING SUCH MATERIAL |
Country Status (3)
| Country | Link |
|---|---|
| DE (1) | DE4030170A1 (en) |
| FR (1) | FR2928779A1 (en) |
| GB (1) | GB2444759B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023024260A1 (en) * | 2021-08-26 | 2023-03-02 | 南通大学 | Multifunctional stealth material and preparation method therefor |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104910492B (en) * | 2015-06-16 | 2017-03-22 | 中原工学院 | Preparation method of ethylene propylene diene monomer/polyaniline/high density polyethylene composite conducting material |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL7610673A (en) * | 1976-09-25 | 1978-03-29 | Stamicarbon | PROCESS FOR PREPARING AN ELECTRICALLY CONDUCTIVE THERMOPLASTIC ELASTOMER. |
-
1989
- 1989-09-25 FR FR8912514A patent/FR2928779A1/en not_active Withdrawn
-
1990
- 1990-09-24 GB GB9020779A patent/GB2444759B/en not_active Expired - Fee Related
- 1990-09-24 DE DE4030170A patent/DE4030170A1/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023024260A1 (en) * | 2021-08-26 | 2023-03-02 | 南通大学 | Multifunctional stealth material and preparation method therefor |
Also Published As
| Publication number | Publication date |
|---|---|
| DE4030170A1 (en) | 2009-02-26 |
| GB2444759A (en) | 2008-06-18 |
| GB2444759B (en) | 2008-11-12 |
| GB9020779D0 (en) | 2008-02-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0308334B1 (en) | Composite magnetic material and process for its production | |
| CH700325B1 (en) | Tray negative electrode, alkaline cell and methods for their manufacture. | |
| EP0448426A1 (en) | Absorbant coating composition, preparation thereof and cladding obtained therefrom | |
| FR2681189A1 (en) | AMORPHOUS SILICON SOLAR CELL AND METHOD FOR MANUFACTURING THE SAME | |
| EP2545753A1 (en) | Method for the treatment of a metal contact formed on a substrate | |
| FR2655997A1 (en) | ABSORBENT COATING, PROCESS FOR PRODUCING THE SAME, AND COATING OBTAINED USING THE SAME | |
| FR2928779A1 (en) | MATERIAL ABSORBING ELECTROMAGNETIC WAVES AND STRUCTURE USING SUCH MATERIAL | |
| KR100672954B1 (en) | Method for treating polymer surface | |
| FR2484709A1 (en) | IMPROVEMENT TO THE PRODUCTION OF A SOLAR CELL TO NEUTRALIZE THE RISKS OF BAD ISOLATION IN THE PLACE OF THE EDGES | |
| Jatratkar et al. | Glow discharge plasma polymerized nanostructured polyaniline thin film optical waveguide | |
| CH699741B1 (en) | alkaline cell and its manufacturing method. | |
| FR2545986A1 (en) | PROCESS FOR FORMING OHMIC CONTACTS OF PURE SILVER ON N-TYPE AND P-TYPE GALLIUM ARSENIDE MATERIALS | |
| EP0149394B1 (en) | Process for making a panel made of polypropylene as basic component, which has several metallic layers, and panel made according to this process | |
| CN111204986A (en) | Preparation method of novel graphene oxide-ITO (indium tin oxide) composite film | |
| EP1097254B1 (en) | Foam-coating method for making antenna elements | |
| EP0142180B1 (en) | Method of making a moulded body of plastic material covered by a metallic layer, and plane antenna so realized | |
| EP0375542B1 (en) | Reflector of electromagnetic waves for an antenna, and method for its manufacture | |
| FR2656146A1 (en) | Material absorbing electromagnetic waves and process for its manufacture | |
| EP1719201B1 (en) | Slot-line-type microwave device with a photonic band gap structure | |
| FR2651690A1 (en) | ACOUSTIC ABSORBENT MATERIAL AND ANECHOIC COATING USING SUCH MATERIAL. | |
| EP0635585B1 (en) | Process for producing a thick and strongly adhering metallic layer on sintered aluminium nitride and metallised product thus obtained | |
| FR2682536A1 (en) | BIPOLAR ELECTRODES FOR LEAD ACCUMULATOR. | |
| FR3092201A1 (en) | A method of manufacturing a radio frequency device comprising a solid three-dimensional network of dielectric meshes | |
| Cheng et al. | Frequency modulation and device repaired by laser surface treatment in film bulk acoustic filters | |
| Matevosyan et al. | Single-Layer Amorphous Carbon Anti-Reflective Coatings Obtained by The Pulsed Laser Deposition Method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| ST | Notification of lapse |
Effective date: 20111223 |