公开(公告)号：JPH09186465A

公开(公告)日：1997-07-15

申请号：JP34251495

申请日：1995-12-28

Applicant: NEC CORP

Inventor： SASAKI HIDEKI ,  HARADA TAKASHI

IPC: H05K3/00 ,  G06F17/50 ,  H05K3/46

Abstract: PROBLEM TO BE SOLVED: To avoid restriction on the wiring of signal pattern when a signal pattern extends over the boundaries of a plurality of power supply regions while preventing increase of the number of devices and avoiding trouble in high density mounting by decreasing the area of loop formed by the signal pattern and the return current path thereof. SOLUTION: Signal patterns 5 are arranged, at an interval longer than the radius of clearance, on the signal layer of a printed circuit board having the signal layer, a power supply layer and a ground layer. The signal patterns are paired and the via holes on a signal pattern in a same set are arranged closely while insulating the signal patterns from each other. Via holes of signal patterns 5b, 5c in different sets are arranged at an interval longer than the sum of the diameter of clearance and the width of one signal pattern and a clearance 7a, 7b is provided around each via hole. Consequently, the return current path of signal pattern is ensured in the vicinity of signal pattern and electromagnetic radiation due to the signal pattern and the return current path thereof is suppressed.

公开(公告)号：JPH06176823A

公开(公告)日：1994-06-24

申请号：JP32904592

申请日：1992-12-09

Applicant: NEC CORP

Inventor： HARADA TAKASHI ,  HATAKEYAMA KENICHI

IPC: H01R13/719 ,  H01F17/06 ,  H01R13/7193 ,  H05K9/00

Abstract: PURPOSE:To provide a shield cable for communication having a structure in which a high frequency current is hard to flow to an outer skin of a shield layer which can be applied to a cable connection part at which a shield connector cannot be used because of formation or space in spite of low cost. CONSTITUTION:At an end part of a shield cable 1 for signal communication composed of a signal line 5 and a shield layer 2, a cylindrical conductor 3 is provided concentricly on the outer side of the shield layer 2. The cylindrical conductor 3 is shortcircuitted with the shield layer 2 by a shortcircuitting plate 4, and a cylindrical magnetic body 7 is inserted between the cylindrical conductor 3 and the shield layer 2. Structurally, the magnetic body 7 is exposed electromagnetically as it is seen from the side of the end part of the cable 1. The shield layer 2 and a casing 8 are connected to each other by a conductor 6 provided at the end part of the cable 1.

公开(公告)号：JPH05302946A

公开(公告)日：1993-11-16

申请号：JP9467692

申请日：1992-04-15

Applicant: NEC CORP

Inventor： HARADA TAKASHI

IPC: G01R29/08

Abstract: PURPOSE:To evaluate a shielding effect with reference to an arbitrary wave source by a method wherein a high-frequency signal generator, an antenna which radiates and receives a high-frequency magnetic field and the like are provided and the transfer impedance of a shielded object is computed from an obtained leakage electromagnetic-wave characteristic. CONSTITUTION:A measuring system applies a condutive gasket material 18 to a gap part 17 in a metal enclosure 16; it is composed of a network analyzer 12, a loop antenna 13 for high-frequency magnetic-field radiation use, a loop antenna 14 for reception use and a coaxial cable 15 which connects them. A transmitter and a receiver are built in the analyzer 12; the analyzer simultaneously measures the amplitude and the phase of leakage electromagnetic waves. By this constitution, an electromagnetic-wave leakage characteristic with reference to a high-frequency magnetic field in a shielding structure part is measured. A transfer impedance or a contact resistance is found from its result by using a prescribed formula. The transfer impedance or the contact resistance and an operating impedance which is formed by an arbitrary wave source are substituted in another prescribed formula. A shielding effect with reference to all wave sources is found.

公开(公告)号：JPH0526930A

公开(公告)日：1993-02-05

申请号：JP20656391

申请日：1991-07-23

Applicant: NEC CORP

Inventor： HARADA TAKASHI ,  HAYASHI MASAYO ,  HATAKEYAMA KENICHI

IPC: G01R29/08

Abstract: PURPOSE:To obtain an electromagnetic wave source analyzing system for obtaining wave source distribution which contributes to measures for suppressing spurious electromagnetic wave radiation, an electromagnetic field analyzing system for obtaining a radiation electromagnetic field without being affected by a surrounding electromagnetic environment, and a measurement device which measures electromagnetic field distribution which is indispensable in terms of two system configurations. CONSTITUTION:An electromagnetic field distribution measurement device 1 consists of two calibrated electromagnetic field measurement probes 3,3 facing each other, an electromagnetic field probe supporting portion 4 which supports the electromagnetic field measurement probes 3, a pole 5 which becomes a guide for moving the electromagnetic field measurement probes 3 up and down, a rotary table 6 which rotates the electromagnetic field measurement probe 3 by 180 degrees in reference to an electronic equipment main body, a table 7 for fixing an object to be measured where the electronic equipment main body is placed. and a ground portion 8. Although the rotary table 6 can be rotated. only height of the table 7 for fixing an object to be measured can be adjusted and it cannot be rotated.

公开(公告)号：JPH0526928A

公开(公告)日：1993-02-05

申请号：JP20324591

申请日：1991-07-19

Applicant: NEC CORP

Inventor： HAYASHI MASAYO ,  HATAKEYAMA KENICHI ,  HARADA TAKASHI

IPC: G01R29/08

Abstract: PURPOSE:To enable current distribution to be calculated from an electromagnetic field measured by an electromagnetic field measuring device and at the same time to control an electromagnetic environment by utilizing information of the electromagnetic field predicted by the current distribution designed artificially. CONSTITUTION:An electromagnetic field close to a wave source of an electromagnetic field measurement device 10 is measured. obtaining an electromagnetic field data, where a measurement value is first read and then a constant which is used by an electromagnetic equation is input. Furthermore. a green function is calculated, obtaining current distribution by the method of least squares. The data is compared with a desired electromagnetic field and a user can improve wave source distribution if there is a need for improvement. On the other hand. an artificial current distribution is designed by a user, a new current distribution is proposed, and the electromagnetic field in that case is calculated by an electromagnetic field prediction program, where a user who treats a physical wave source distribution performs treatment for improvement based on current distribution before treatment, a proposed current distribution, and the electromagnetic field according to the proposed current distribution. The result can be confirmed by the measuring device 10.

公开(公告)号：JPH0513979A

公开(公告)日：1993-01-22

申请号：JP19350691

申请日：1991-07-08

Applicant: NEC CORP

Inventor： HARADA TAKASHI

IPC: H05K9/00

Abstract: PURPOSE:To provide an electromagnetic shielding body around the joint or the door of a metal case so as to prevent electromagnetic wave from leaking out of the metal case concerned. CONSTITUTION:An electromagnetic shielding body 1 is of integral structure composed of a conductor rod 5 provided with a groove U-shaped in cross section and a magnetic substance 2 formed of a rod-like magnetic substance 3 and a rod-like magnet 4 and filled into the groove provided to the conductor 5. As the rod-like magnet 4 is magnetized in a direction vertical to the lengthwise direction, the rod-like magnetic substance 3 kept in contact with the rod-like magnet 4 is magnetized in a crosssectional direction. Therefore, the shielding body 1 becomes high in magnetic permeability to a magnetic component in the lengthwise direction of the magnetic substance, so that it enables leakage electromagnetic waves possessed of a magnetic field component in the same direction to be much attenuated. Therefore, a metal case mounted with an electromagnetic shielding body of this design is not required to be equipped with a special structure so as to come into tight contact with the shielding body and has an enough shielding effect to a electromagnetic wave source of low impedance.

公开(公告)号：JPH03245597A

公开(公告)日：1991-11-01

申请号：JP4283590

申请日：1990-02-23

Applicant: NEC CORP

Inventor： HARADA TAKASHI ,  HATAKEYAMA KENICHI

IPC: H05K9/00

Abstract: PURPOSE:To reduce an electromagnetic wave which leakes out of a cable insertion opening to the irreducible minimum by a method wherein a cut of the crossed cuts provided to a conductive fiber material shielding body through which a cable or a cord is inserted is formed of a magnetized magnetic substance and the other cut edge is formed of a non-magnetized magnetic substance. CONSTITUTION:Cross-shaped or radially arranged cuts 2 through which a cable or a cord is inserted are provided to a shielding main body 1 formed of conductive fiber material, and a non-magnetized magnetic substance is provided to a cut edge 2a out of the crossed cuts 2 and magnetized magnetic substances or permanent magnets 3 arranged reverse to each other in polarity are provided to the other cut edge 2b of the crossed cuts 2. When a signal cable 6 is inserted into an opening, the cross cuts 2 are kept in conductive contact with each other except a small part around the cable 6, an electromagnetic wave leaking out of an insertion opening can be reduced to the irreducible minimum.

公开(公告)号：JPH03226000A

公开(公告)日：1991-10-04

申请号：JP2179690

申请日：1990-01-31

Applicant: NEC CORP ,  NEC ENVIRONMENT ENG LTD

Inventor： HARADA TAKASHI ,  HATAKEYAMA KENICHI ,  KIZAKI TAKASHI ,  YOSHIUCHI AKIRA

IPC: H05K9/00

Abstract: 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.

公开(公告)号：JPH03131092A

公开(公告)日：1991-06-04

申请号：JP26987389

申请日：1989-10-17

Applicant: NEC CORP

Inventor： HARADA TAKASHI ,  HATAKEYAMA KENICHI

IPC: E06B5/18 ,  H05K9/00

Abstract: PURPOSE:To im[rove shielding performance irrespective of the same opening area and depth by covering the wall surface of a cavity with a high permeability material in a honeycomb structure composed of a conductor such as metal, etc., and having many aligned hexagonal-sectional cavities. CONSTITUTION:In a honeycomb structure 1 composed of a conductor such as metal, etc., and in which cavities each having sufficiently small size as compared with a wavelength are aligned, the inner wall of the cavity is covered with a high permeability material 2. An electromagnetic wave shield having both the interval of the opposed surface and a depth in one cavity are 1cm provides approx. 42dB of maximum shielding effect obtained in a frequency band of several hundreds of MHz. This provides 10dB larger than that of a conventional honeycomb structure electromagnetic wave shield having the same size. If this shield is mounted in the opening of an electronic apparatus housing 3, a conductive gasket 4, etc., is necessarily used to improve its contact state with the housing 3 and to suppress leakage of an electromagnetic wave from the shield mount as much as possible to obtain sufficient electromagnetic wave shielding effect of the original shield.

公开(公告)号：JPH01100475A

公开(公告)日：1989-04-18

申请号：JP25783487

申请日：1987-10-13

Applicant: NEC CORP

Inventor： HARADA TAKASHI

IPC: G01R31/28 ,  G06F19/00

Abstract: PURPOSE:To achieve an automation of verifying functions of a circuit causing a bit deviation, by comparing an expected value with the results of simulation when shifted within a range of a bit deviation allowed respective to one expected value of simulation. CONSTITUTION:An expected value of simulation is stored by an expected value pattern memory means 2. An output of the memory means is inputted to an expected value generating means 3 and an output is generated as obtained by shifting the expected value within an range of bit deviation allowed and stored into a bit deviation expected value memory means 4 per number of bit deviation. The results of the simulation are stored into a simulation results memory means 1. Outputs of the memory means 1 and 4 are inputted into a collation means 5 to compare a bit deviation expected value with the results per number of bit deviation. The results with the pattern of the highest coincidency are selected and outputted such as of collation, thereby eliminating effect of deviation in bit.