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1. 发明专利

JPH0521982A ELECTROMAGNETICWAVE ABSORBER 失效
公开(公告)号：JPH0521982A
公开(公告)日：1993-01-29
申请号：JP19722391
申请日：1991-07-11
申请人： NEC ENVIRONMENT ENG LTD , NEC CORP , TODA KOGYO CORP
发明人： KIZAKI TAKASHI , YOSHIUCHI AKIRA , HATAKEYAMA KENICHI , YAMAMOTO SHIGEHISA
IPC分类号： H05K9/00
摘要： PURPOSE:To reduce the thickness of a electromagneticwave absorber by using a water-absorptive electrolyte as the filler to increase the dielectric constant of the absorber. CONSTITUTION:Utilizing that a water-absorptive electrolyte contains a constant amount of moisture under a constant temperature and humidity, it is filled with an open cell foam to increase dielectric constant. That is, as conventional, filling carbon black is added with a constant amount of electrolyte to give a electromagneticwave loss. This way enables an increase in dielectric constant and a decrease in height of a electromagneticwave absorber.

2. 发明专利

JPH05291782A 失效
公开(公告)号：JPH05291782A
公开(公告)日：1993-11-05
申请号：JP11541992
申请日：1992-04-08
申请人： NEC CORP , TODA KOGYO CORP , NEC ENVIRONMENT ENG LTD
发明人： HATAKEYAMA KENICHI , HANKOU EIJI , YAMAMOTO SHIGEHISA , YOSHIUCHI AKIRA
IPC分类号： H05K9/00
摘要： PURPOSE:To stabilize electric wave absorbing performance and then reduce weight by mixing three types, namely a base material, a filling substance, and a conductive substance, simultaneously or constituting an electronic absorber by mixing either two types and then mixing the remaining one type to the mixture. CONSTITUTION:A base material such as a paint, rubber, and epoxy resin, a non-conductive and non-magnetic granular object such as granular polyetylene, expanded stylene beads, and glass ball, and a conductive material such as a conductive particle and a conductive fiber are mixed simultaneously or two types, namely a base material such as epoxy resin and a filling substance such as expanded styrene beads with a diameter of 6mm are mixed and then the conductive material such as conductive particle and conductive fiber are mixed to these two types, thus constituting an electric wave absorber. In this manner, a secondary surface is constituted on purpose and then a conductive particle, a conductive fiber, or a magnetic particle is laid out on the secondary surface, thus maldistributing the particle and hence stabilizing electric wave absorbing performance.

3. 发明专利

JPH03226000A WAVE ABSORBER 失效
公开(公告)号：JPH03226000A
公开(公告)日：1991-10-04
申请号：JP2179690
申请日：1990-01-31
申请人： NEC CORP , NEC ENVIRONMENT ENG LTD
发明人： HARADA TAKASHI , HATAKEYAMA KENICHI , KIZAKI TAKASHI , YOSHIUCHI AKIRA
IPC分类号： H05K9/00
摘要： PURPOSE:To obtain a wave-absorbing characteristic whose attenuation amount is high by a method wherein a conductive fiber dispersion dielectric layer composed of a dielectric in which conductive fibers are dispersed into a high-polymer resin is laid between the layer of a magnetic loss body such as a ferrite or the like and the layer of a dielectric loss body in which a conductor such as carbon graphite or the like is dispersed into a high-polymer resin. CONSTITUTION:A laminated body of a magnetic loss body 2, a conductive fiber dispersion dielectric layer 3 and a dielectric loss body 4 is formed on the surface of a conductor 1. The magnetic loss body 2 is a nickel-zinc ferrite sintered body. The conductive fiber dispersion dielectric layer 3 is molded by spraying carbon fiber as conductive fibers 5 which have been dispersed into a glass fiber. The dielectric loss body 4 on the conductive fiber dispersion dielectric layer 3 is a pyramid-shaped molded body of foamed urethane to which carbon has been dispersed. It is possible to obtain a high attenuation amount over a wide band from several tens of MHz to several tens of GHz or higher.

4. 发明专利

JPH01179399A RADIO WAVE ABSORBER 失效
公开(公告)号：JPH01179399A
公开(公告)日：1989-07-17
申请号：JP93988
申请日：1988-01-05
申请人： NEC CORP
发明人： INUI TETSUJI , HATAKEYAMA KENICHI , YOSHIUCHI AKIRA
IPC分类号： H05K9/00 , H01Q17/00
摘要： PURPOSE:To obtain a sheet-shaped thin radio wave absorber which has good characteristics in both vertical incidence and grazing incidence, by a structure wherein strip-shaped radio wave absorber sheets each of which has the specific thickness and length for a wavelength lambda are arranged cyclically in a surface of a dielectric sheet made of a material with relative low loss and buried therein. CONSTITUTION:Strip-shaped high loss sheets 1 (radio wave absorber sheets) are inserted into a low loss sheet 2 (dielectric sheet) and the size of each the strip-shaped high loss sheet 1 is adjusted to the predetermined wavelength, and thereby both wave absorber and wave scattering effects are obtained in the strip-shaped high loss sheets 1. Further, a plurality of the strip-shaped high loss sheets 1 are superposed each other, and thereby in addition to said effects, a multiple reflection effect is obtained among the strip-shaped high loss sheets 1, 1,.... Moreover, medium constants of the strip-shaped high loss sheet 1 and the low loss sheet 2, and thickness of the low loss sheet 2, and inserting positions, shape and arranging method about the strip-shaped sheets 1 are adjusted, respectively, and thereby a radio wave absorber can be provided which has good characteristics in both vertical incidence and grazing incidence. The size factors of the wave absorber are set for a wavelength lambda as follows ; d w in length.

5. 发明专利

JPH0273699A ELECTRIC WAVE ABSORBER 失效
公开(公告)号：JPH0273699A
公开(公告)日：1990-03-13
申请号：JP22563888
申请日：1988-09-09
申请人： NEC CORP
发明人： YOSHIUCHI AKIRA , INUI TETSUJI
IPC分类号： H01Q17/00 , H05K9/00
摘要： PURPOSE:To constitute an electric wave absorber which has wideband and favorable leaning incidence characteristics and is small in strength deterioration by using an electric wave absorber where nonwoven fabric containing conducting material is formed in roll shape. CONSTITUTION:Conductive fiber can be dispersed at random in the x and y planes. When it is rolled, the directions of dispersions of conductive fibers are three-dimensions and those are dispersed at random. The length of the conductive fibers is selected by the dimensions, weight, etc., of the fiber. By making it in roll shape and keeping the mechanical strength of fabric and selecting resin fiber properly, the property such as durability, heat resistance, oil resistance, etc., is adjusted. By the random dispersion of conductive fibers in three dimensions, whatever directions the electric wave may come from, the loss and dispersion by conductive currents can be obtained, and decrease of reflection at the surface and dispersion effect at the surface can be obtained, and a suitable electric wave absorber can be made. If it is provided at the surface of a flat electric wave absorber the characteristics can be improved significantly.

6. 发明专利

JPH01187896A MATERIAL FOR RADIO WAVE ABSORBER 失效
公开(公告)号：JPH01187896A
公开(公告)日：1989-07-27
申请号：JP1195788
申请日：1988-01-21
申请人： NEC CORP
发明人： INUI TETSUJI , HATAKEYAMA KENICHI , YOSHIUCHI AKIRA
IPC分类号： H05K9/00 , H01Q17/00
摘要： PURPOSE:To lighten an absorber compared with a sheetlike absorber having used gum or paint, and to obtain the absorber with excellent wide-band characteristics and oblique-incidence characteristics, by making a sheetlike substance contain conductive fibers with the coating of a good conductor metal on the surfaces of long and slender fiberlike resins, and insulating fiberlike resins without the coatings of a good conductor metal. CONSTITUTION:A good conductor metal such as cupper, nickel etc., is coated on the surface of a fiberlike resin being an insulator electrically, to make a conductive fiber A. Then, the fibers A are mixed with fiberlike resins B being an insulator, to make a nonwoven fabric sheetlike absorbing material. When used as a material for a radio wave absorber, it is effective that the above- mentioned conductive fibers A and insulating fibers B are mixed in the range of 0.5 to 10% by weight. Four layers from the first layer 1 to the fourth layer 4, for example, are laminated to make an absorber. Each layer is a mixture of the good conductive fibers A and the insulating fibers B in the weight ratios of 5%, 3%, 1.5$% and 1% respectively, and each layer is equally 3nm in thick ness. Polyacrylonitrile and polyethylene are used for the firbers A and B, and nickel is used as a coating metal of the fiber A.

7. 发明专利

JPH0212995A RADIO WAVE ABSORBER 失效
公开(公告)号：JPH0212995A
公开(公告)日：1990-01-17
申请号：JP16433088
申请日：1988-06-30
申请人： NEC CORP
发明人： YOSHIUCHI AKIRA , INUI TETSUJI
IPC分类号： H05K9/00
摘要： PURPOSE:To realize a radio wave absorber which has a small size, a flat surface, wide band and satisfactory oblique incident characteristic by burying the absorber having scattering effect made of high loss medium in a medium formed by laminating nonwoven fabrics made of resin fiber, conductive fiber. CONSTITUTION:15 sheets of nonwoven fabrics formed by mixing conductive fiber 4 on a metal plate 5 are so inserted that high loss sheets 3 are sequentially inserted between first to tenth layers from the plate side of a laminate 1 so as to be reduced in shape thereby to construct a scattering type absorber 2. The sheet 3 employs nonwoven fabric mixed with the fiber 4. In this case, a radio wave absorber having a small size, a flat surface, wide band and satisfactory oblique incident characteristic can be designed by regulating the length of the fiber 4 of the fabric, mixing ratio, thickness of the laminated layer, the shape, loss of the absorber 2.

8. 发明专利

JPH0212998A RADIO WAVE ABSORBER 失效
公开(公告)号：JPH0212998A
公开(公告)日：1990-01-17
申请号：JP16433388
申请日：1988-06-30
申请人： NEC CORP
发明人： YOSHIUCHI AKIRA , INUI TETSUJI
IPC分类号： H05K9/00
摘要： PURPOSE:To realize a radio wave absorber which has satisfactory oblique incident characteristic and wide band by alternately laminating nonwoven fabrics having different conductivities, and forming a cavity in the nonwoven fabric having large conductivity. CONSTITUTION:Nonwoven fabrics having different conductivities are alternately laminated, and a cavity is formed in the nonwoven fabric having large conductivity. First, nonwoven fabric made of conductive fiber and polymer resin fiber is employed as a medium. This nonwoven fabric has means as stereoscopically disposed medium of the conductive fiber, becoming locally irregular in electromagnetic wave manner. As a result, radio wave characteristic which cannot be obtained in the homogeneous medium is provided, and Fn (n=1, 2,...) sheet corresponds thereto. Second, the nonwoven fabric sheet having larger conductivity than that of the Fn sheet is formed, and a medium formed with punched holes is introduced thereinto. It has the same characteristic in the electromagnetic wave manner, but its operating region is increased, and Mn (n=1, 2,...) sheet corresponds thereto. The hole has an arbitrary shape and size, thereby variously altering the characteristics of the Mn sheet.

9. 发明专利

JPH01230299A FORMING METHOD OF RADIO WAVE ABSORBENT SKIN FILM AND RADIO WAVE ABSORBER COMPOSITION 失效
公开(公告)号：JPH01230299A
公开(公告)日：1989-09-13
申请号：JP5496688
申请日：1988-03-10
申请人： NEC CORP , KANSAI PAINT CO LTD , HONSHU SHIKOKU RENKAKUKYO
发明人： INUI TETSUJI , YOSHIUCHI AKIRA , SHIRAI KENZO , NAKAYA TOSHIKAZU
IPC分类号： C04B14/36 , C04B26/02 , C08K3/02 , C08K3/04 , H01Q17/00 , H05K9/00
摘要： PURPOSE:To obtain a light-weight thin film, by using radio wave absorber composition whose indispensable component is scaly graphite wherein the content of fixed carbon, grain diameter, and the ratio of the mean length of grain diameter and the mean thickness are specified. CONSTITUTION:Scaly graphite is composed of natural or articial scaly graphite of 5-60 part by weight, and synthetic resin of organic polymer or polymerizable monomer of 95-40 part by weight. As to the scaly graphite, the following are used: the content of fixed carbon is higher than or equal to 80% (preferably 85% or more), grain diameter is 200-800mum (preferably 300-500mum), and the ratio L/D (aspect ratio) of the mean length L of grain diameter and the mean thickness D is larger than or equal to 50. The thickness of scaly graphite is set as 0.1-10mum, which is preferably 0.5-1mum. As an example of synthetic resin, phenol resin, urea resin, etc., are used. Thereby, radio wave absorbing film is made light-weight (specific weight is small), and the thickness is made thin, so that high frequency radio wave of 9-10GHz can be highly absorbed.

10. 发明专利

JPS63168093A WAVE ABSORBER 失效
公开(公告)号：JPS63168093A
公开(公告)日：1988-07-12
申请号：JP31182986
申请日：1986-12-29
申请人： NEC CORP
发明人： INUI TETSUJI , HATAKEYAMA KENICHI , YOSHIUCHI AKIRA
IPC分类号： H05K9/00 , H01Q17/00

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