EMCJ99-101 (1999-12)

Power Decoupling Circuit for Measurement of EMC Characteristics of IC/LSI

Osami WADA, Ryuji KOGA, and Yukihiro FUKUMOTO*

Faculty of Engineering, Okayama University

* Matsushita Electric Industrial Co., Ltd.

3-1-1 Tsushima-naka, Okayama

Abstract: Basic concept and outline are described of measurement methods of EMC characteristics of semiconductor devices, particularly on the magnetic probe method proposed in SC47A/WG9 of IEC, and a power decoupling circuit is proposed for reducing effects of impedance of power system outside EUT. The decoupling circuit can also be used in measurement for modeling of power current of IC/LSI. With the decoupling circuit, current flowing toward outside circuit is simulated and it is reduced under -50dB.

Key words: IC/LSI, EMC characteristics, power decoupling, magnetic probe method, modeling


EMCJ99-102 (1999-12)

Two-dimensional Analysis for Power Distribution Planes in Multilayer Printed Circuit Boards

Takashi HARADA*, Kiyoshi ASAO**, Hideki SASAKI*, and Yoshio KAMI***

*Device Analysis Technology Laboratories, NEC Corporation

**Production Systems Development Laboratories, NEC Corporation

***The University of Electro-communications

*4-1-1 Miyazaki Miyamae-ku Kawasaki, Kanagawa 216-8555

**3-484 Tsukakoshi Saiwai-ku Kawasaki, Kanagawa 210-8511

***1-5-1 Choufugaoka Choufu-shi, Tokyo 182-8585

Abstract: This report analyzes transmission and impedance characteristics of power distribution planes in multilayer printed boards with SPICE. A two-dimensional circuit model, which consists of capacitors, inductors, and resistors, is used to analyze the characteristics. Accurate analysis can be achieved to incorporate effect of circuit losses appropriately. The characteristics involving decoupling capacitors can be analyzed by considering effects of interconnect inductance. Voltage distributions in the planes are also analyzed. It is shown that voltage magnitude depend on source point. The information on the voltage distributions is effective to design power-distribution-decoupling and PCB layout.

Key words: EMC, EMI, Printed circuit board, Power/Ground , SPICE


EMCJ99-103 (1999-12)

A New Model of LSI at Power Supply Terminal for EMI Simulation

Masashi OGAWA, Hiroshi WABUKA, and Hirokazu TOHYA

EMC Engineering Center, Device Analysis Technology Labs, NEC Corporation

1-1, Miyazaki 4-Chome, Miyamae-ku, Kawasaki, Kanagawa 216-8555 JAPAN

Abstract: A radio frequency (RF) current passing from power supply terminals into ground terminals in a LSI on a printed circuit board (PCB) is one of the main factor at electricmagnetic interface (EMI) from circuit system, then it is important to simulate for EMI to use an appropriate model for LSI. In this report, a new LSI model by simplifying all network data of internal LSI circuit is proposed, which is composed of transistors and load capacitors, and the simulated values of current spectra in the power supply line of a PCB using the proposed model agreed well with the measured values.

Key words: LSI model at power supply terminal, simulation, LSI internal capacitor


EMCJ99-104 (1999-12)

Power Current Model of IC with Internal Impedance

Yasuo TAKAHATA, Atsushi WATANABE, Osami WADA, Ryuji KOGA, and Yukihiro FUKUMOTO*

Faculty of Engineering, Okayama University

*Matsushita Electric Industrial Co., Ltd.

3-1-1, Tsushima-naka, Okayama 700-8530

*1006 Kadoma, Kadoma City, Osaka 571-8501

Abstract: The main cause of electromagnetic radiation from a digital PCB is high-speed switching current flowing on power supply pins of IC/LSI. To estimate and to reduce EMI, we need a behavior model to evaluate high frequency current at a power supply terminal of an IC. In this report, the authors propose an equivalent circuit model which is composed of an equivalent internal current source and an equivalent internal impedance to express current penetrating an IC from a power pin to ground. To verify the model, simulated results of reduction of high frequency current when inserting a series inductor on a power supply line is shown with correspondent results of measurement.

Key words: EMI, IC/LSI, simulation, high frequency current, current source model, internal impedance


EMCJ99-105 (1999-12)

Calculation Models for a Magnetic Shielding Effectiveness Measuring Instrument

Tomoki Matsubara,  Atsuhiro Nishikata* , Yasutaka Shimizu**, and Yukio Yamanaka***

Graduate school of Science and Engineering, Tokyo Institute of Technology

*CRADLE, Tokyo Institute of Technology

**Graduate school of Decision Science and Technology, Tokyo Institute of Technology

***Communications Research Laboratory / MPT

2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552

Abstract: The SE (Shielding Effectiveness) value of shielding material vary depending on the evaluation method used. In this report, we propose four types of calculation models for calculation of SE, obtained by one of popular measurement methods (KEC method) of magnetic SE. The first model assumes a magnetic dipole source and an infinitely-large plane shield, by which the measured SE is well-predicted when the distance between the source point and the observation point is assumed as 17mm. Second model (Schelkunoff's model), which is one-dimensional and easy-to-calculate, is found to be well-applied when r=6mm is assumed. The resistive sheet approximation for the shielding material is introduced into both the previous model and the 3-dimensional FDTD model. The validity of resistive sheet approximation is shown by comparison of calculated SE with measured one, as well as the validity of each models.

Key words: Magnetic Shielding Effectiveness Measuring Instrument, Electromagnetic Shielding, Dipole source, Schelkunoff's formula, resistive sheet, 3D-FDTD


EMCJ99-106 (1999-12)

System Response of the FET Input Static Voltmeter with a Rod Electrode


Industrial Research Institute, Aichi Prefectural Government

Hitotsugi-cho, Nishishinwari, Kariya-shi, Aichi 448-0003 Japan

Abstract: This study describes the characteristics of the tip on the probe that detects the field potential. The figure of the probe tip is a small rod. This probe tip is connected to the input of high impedance amplifier of the static voltmeter for the potential measurement. The effect of the tip length is measured using a circular electrode that is driven by pulse voltage to generate a known potential field. The probe senses potential widely around its circumstances. The measured voltage is saturated according to the probe tip length.

Key words: electrostatic charge, charged voltage, probe, voltage distribution, capacitance


EMCJ99-107 (1999-12)

FDTD Computation of Electromagnetic Interference Voltage Induced at an Implanted Pacemaker due to Portable Telephones

Jianqing Wang and Osamu Fujiwara

Department of Electrical and Computer Engineering, Nagoya Institute of Technology

Gokiso-cho, Showa-ku, Nagoya 466-8555 Japan

Abstract: A prediction of the electromagnetic interference (EMI) of pacemakers due to portable telephones is significant in improving the immunity of pacemakers. The Pacemaker Committee of Japan recently conducted immunity tests of pacemakers for portable telephones, and consequently concluded that the connector between the pacemaker housing and the lead wire of electrode plays a major role for the EMI due to portable telephones. Based on this finding, a computer model for predicting the EMI level has been presented, in which the internal impedance looked from the connector and the metal portion consisting of the pacemaker housing and the lead wire of electrode were considered as a load and two halves of a receiving antenna, respectively. Interference voltages induced through the connector were analyzed by using the finite-difference time-domain (FDTD) method in conjunction with a torso and portable telephone model. The modeling was validated by comparison with the previously reported experimental results.

Key words: electromagnetic interference, implanted pacemaker, portable telephone, FDTD analysis

EMCJ99-108 (1999-12)

Dependence on Tissue Structure of Localized Peak SAR inside Head Model for 1.5GHz Microwave Far-field Exposure

Takuji USHIMOTO, Jianqing WANG, and Osamu FUJIWARA

Faculty of Engineering, Nagoya Institute of Technology

Gokiso-cho, Showa-ku, Nagoya 466-8555 Japan

Abstract: We investigated the dependence on the head tissue structure of localized peak SARs (specific absorption rate) inside our newly developed MRI (Magnetic Resonance Imaging) based head model for far-field exposure in all irradiation directions of the microwaves being employed for portable telephones. The FDTD (Finite-Difference Time-Domain) method was used to compute the SARs inside the MRI based head models consisting of various tissues up to 15 kinds for 1.5 GHz microwave far-field exposure of 1 mW/cm2 specified in an uncontrolled environment. As a result, we found that in the head model having less than three kinds of tissue, the localized peak SAR reaches maximum for side irradiation, decreasing with increasing the tissue kind, while in the head model with more than four kinds of tissue, the localized peak SAR reaches maximum for rear irradiation, whose value increases with the tissue kind and reaches saturation point for over five tissues including skin, fat, muscle, bone, and brain. The latter finding suggests that the head model having the above five tissues at most can be used enough for dosimetry evaluation with high accuracy.

Key words: Microwave far-field exposure, dosimetry, FDTD analysis, MRI based head model, tissue-structure dependence


EMCJ99-109 (1999-12)

Study of Electromagnetic Scattering by Buildings in Digital TV Broadcasting Using Partial Conformal Mapping Method

Yasumitsu Miyazaki

Department of Information and Computer Sciences, Faculty of Engineering, Toyohashi University of Technology

Hibarigaoka 1-1, Tempaku-cho, Toyohashi, 441-8580 Japan

Abstract: Recently, instead of analog TV broadcasting, digital TV broadcasting are used as satellite broadcasting and surface broadcasting. In analog TV broadcasting, electromagnetic compatibility problems such as electromagnetic interference and ghost problems due to natural geographical environment and high buildings are severe problems to be solved. Signal processing for electromagnetic compatibility problems are also required for strong interference cases even in digital TV broadcasting, although weak interference problems are well processed in case of digital TV broadcastings. In this paper, using partial conformal mapping method, electromagnetic scattering is investigated for interference problems due to high buildings and natural geo-effects.

Key words: digital TV broadcasting / electromagnetic scattering / conformal mapping / electromagnetic compatibility


EMCJ99-110 (1999-12)

Analysis of Electromagnetic Interference Characteristics of Wireless LAN in Buildings by FDTD Method

Koichi Takahashi, Tadahiro Masuda, and Yasumitsu Miyazaki

Department of Information and Computer Sciences, Faculty of Engineering, Toyohashi University of Technology

Hibarigaoka 1-1, Tempaku-cho, Toyohashi, 441-8580 Japan

Abstract: The radio communication systems such as cellular phones and wireless LAN systems have been developed rapidly in the recent years, and accordingly the interference and operational error of electronic systems become serious problems. Therefore, understanding of propagation characteristics of radio communication waves is necessary to develop high performance and reliable communication systems. Ray-tracing method is mainly applied for the analysis of indoor propagation channels. However, for the analysis of complex propagation channels, ray-tracing approach needs complex formulation and very long calculation times. In this paper, FDTD method is applied to show the interference characteristics of radio systems, such as wireless LAN, mobile communication in various structures. The locations inside the buildings, which receive week intensity of electric field are investigated.

Key words: wireless LAN / cellular phone / FDTD method / electromagnetic interference


EMCJ99-111 (1999-12)

Electromagnetic Interference Characteristics by Group of Buildings in High-Speed Mobile Communication Systems

Paul Selormey and Yasumitsu Miyazaki

Department of Information and Computer Sciences, Faculty of Engineering, Toyohashi University of Technology

Hibarigaoka 1-1, Tempaku-cho, Toyohashi, 441-8580 Japan

Abstract: Detailed characterization of radio propagation channel is a major requirement for successful design of mobile communication systems. In this paper, mobile radio channel characterization process based on 2D FDTD method is presented. The merits and demerits of the currently used methods, namely impulse-response method and ray-tracing methods are briefly discussed. Various simulation models consisting of streets with buildings are examined. Wave propagation patterns in the whole channel and the received signals at some line of sight and out of sight locations are presented . The results show that the effects of the number of buildings, not directly surrounding a receiving location, on the received signal is not significant.

Key words: FDTD method / propagation characteristics / wave scattering / mobile radio waves

EMCJ99-112 (1999-12)

Indefiniteness in EMI Methods for In-situ Measurement for Industrial, Scientific and Medical (ISM) Equipment

-Making Clear the Technical Inconsistency Found in In-situ Measurement by CISPR 11 Recommendations-

Shigekazu Shibuya*, Hideya Andou**, Kazuaki Yoshimura**, Haruo Ishizuka*, Toshio Kinoshita***, Akinori Kameshima*, Takashi Suzuki#, Naoki Suzuki##, Yutaka Ohno@, Kunio Takamura, Kouichi Yamaguchi, and Juichi Kaku@@

**Touin Yokohama University

*Shibuya,. Ishizuka or Kameshima Consultant office

***EMCT EMC Study Group

#Net Alpha

##Wooden Bell Consultant



Abstract: CISPR 11 (1997) recommends definitely the methods of in-situ measurement (called "in-situ  measuring method") to cope with interference radiated from large scale ISM equipment. It calls for measuring the field strength at 2m high above the ground and 30 ~ 100m far from the exterior wall of the building in which the equipment is installed, however, it invites a confusion in the field because the test results show a large difference depending on chosen directions. This paper indicates that the basic cause is .in the indefiniteness of the measure and explains its countermeasure.

Key words: EMC, ISM equipment, in-situ measurement, indefinite scale, freespace, U-site

EMCJ99-113 (2000-01)

Experimental Conditions to Calibrate Induced-Current Meters for a Human Body Standing on the Ground Plane and Exposed to RF Fields

Yuya Nakamoto, Soichi Watanabe*, Yukio Yamanaka*, and Masaharu Takahashi

Musashi Institute of Technology

*Communications Research Laboratory, M.P.T

1-28-1 Tamazutsumi, Setagaya-ku, Tokyo 158-8557 Japan

Abstract: Experimental conditions to calibrate induced-current meters for a human body standing on the ground plane and exposed to RF fields are investigated in this report. A resonant mono-pole as a radiation source and another mono-pole as a human body on the ground plane in an anechoic chamber are assumed. The induced current on the receive antenna is calculated with method of moment (NEC-2).

Key words: foot current, induced current, SAR, calibration, method of moment anechoic


EMCJ99-114 (2000-01)

Measuring Method for Digital IC Terminal Output in the High-frequency Range above 1GHz 

Satoshi Kazama, Shinichi Shinohara, and Risaburo Sato

Electromagnetic Compatibility Research Laboratories Co., Ltd.

6-6-3 Minamiyoshinari, Aoba-ku, Sendai-shi 989-3204

Abstract: This paper describes a new technique for evaluating methods of measuring the terminal output of a digital IC. The measured output data is used for evaluating electromagnetic interference (EMI). This technique uses frequency characteristics of the circuit network that is inserted between the digital IC's terminal and the measuring instrument. The characteristics are measured accurately by using a network analyzer at high frequencies. We use this technique to evaluate methods of measuring EMI from digital ICs in the high-frequency range above 1 GHz. These results may improve the systems for measuring the output from an IC terminal.

Key words: Digital IC, Current on terminal, EMI, Measuring method, Evaluation method


EMCJ99-115 (2000-01)

A Method for Estimating the Shielding Effectiveness of Holes on a Small-Size Shield Enclosure

Tsuyoshi Yamato, Fumishiro Tsuda, Shinichi Shinohara, and Risaburo Sato

Electromagnetic Compatibility Research Laboratories Co., Ltd.

6-6-3 Minami-Yoshinari, Aoba-ku , Sendai 989-3204 Japan

Abstract: The electronic field strength in the far field and the intensity of magnetic the field in the near field were measured assuming an application to compact information technology equipment that has recently become widespread and by using a small-sized shield case. In the structure of distributions of the intensity of the magnetic field in the near field, we found that the shielding effectiveness in the far field was determined by the maximum radiation level of the intensity of the magnetic field in the near field from a single hole. We also found that the shielding effectiveness in the far field was related to the intensity of the magnetic field in the near field. Therefore, we estimated the shielding effectiveness in the far field by measuring the radiant intensity of the magnetic field from a single hole.

Key words: shield case, shielding effectiveness , far field , near field

EMCJ99-116 (2000-01)

Prediction of Effect of Noise Suppression Device on Radiated Interference Suppression from Printed Wire

Hidetoshi Yamamoto, Shinichi Shinohara, and Risaburo Sato

Electromagnetic Compatibility Research Laboratories Co., Ltd.

6-6-3, Minami-yoshinari, Aobaku, Sendai 989-3204 Japan

Abstract: In this paper, the suppression effect of noise suppression device on radiated interference suppression from printed wire was discussed. The effect was calculated from transmission theory and results shows good agreement with measured value.

Key words: Electromagnetic interference, Radiated emission, Printed wire, Noise suppression device, Suppression effect


EMCJ99-117 (2000-01)

Electromagnetic Compatibility of Programmable Controllers with High Magnetic Field Environment

M. Hidaka, R. Nagasawa, F. Naitou, S. Shimamoto (Tohoku Univ.), and Y. Murano (Kandenko Co., Ltd.)

Graduate School of Engineering, Tohoku University

05 Aoba-yama, Aoba-ku, Sendai 980-8579

Abstract: As the superconducting magnetic facilities are widely used, electromagnetic interference due to the leakage magnetic field from the superconducting facility have been gradually increased. This paper describes about the electromagnetic compatibility test results of the programmable controller (PC) in high magnetic field up to 2kG. The PC units , which include transformers having magnetic core, are apt to be highly affected by the leakage magnetic field. Therefore, characteristic of transformers magnetized by the external DC field is described. And the magnetic shielding capability of ferromagnetic plate are also discussed in this paper.

Key words: Electromagnetic Compatibility, Programmable Controllers, Leakage Magnetic Field, Magnetic Shielding

EMCJ99-118 (2000-01)

The Effect of a Finite Ground Plane on the S-parameter between Two Dipole Elements

Katsumi Fujii and Takashi Iwasaki

Department of Electronic Engineering, The University of Electro-communications

1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 Japan

Abstract: The S-parameter between two dipole antenna elements on a finite ground plane is measured in horizontal polarization using a network analyzer with TRL calibration technique. The S21 is also calculated using the hybrid method combined the method of moment (MoM) with the geometrical theory of diffraction (GTD) and using the MoM in which the finite ground plane is divided to planar-segments. The results show that the S-parameter can not be evaluated by the hybrid method but can be evaluated by the MoM. It makes clear that the antenna element direction of a rectangular ground plane should be wider when a large ground plane can not be used.

Key words: S-parameter, Finite ground plane, MoM, GTD, TRL calibration

EMCJ99-119 (2000-01)

Measurement of Normalized Site Attenuation using Biconi-log Antennas

Atsuo Senga and Takashi Iwasaki

Department of Electronic Engineering, The University of Electro-communications

1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 Japan

Abstract: Normalized site attenuation (NSA) obtained with a pair of biconi-log antennas is theoretically investigate using the moment method. It is found that the radiation patterns, the positions of active antenna elements and the height dependence of antenna factor have influence on the difference in NSA between measurement values with biconi-log antennas and the specified values in CISPR 16.

Key words: Biconi-log antennas, Site attenuation, Moment method, Antenna factor


EMCJ99-120 (2000-01)

Lightning Protection for Information-oriented and Computerized Society

- Present State and Future Project -

Sigeru Yokoyama

Komae Research Laboratory, Central Research Institute of Electric Power Industry

2-11-1, Iwado Kita, Komae-shi, Tokyo 201-8511 JAPAN

Abstract: Outages due to lightning strokes has been increasing in electronic circuits, computers and telecommunication systems inside a building.

 We show a few examples of lightning outages concerning such a facilities. Moreover, we summarize overseas regulations related to lightning protection measures of electronic circuits in a building and indicate problems when applied to Japanese conditions. Finally we propose several projects which are very important for better protection measures against lightning hazards to electronic circuits and computer networks.

Key words: lightning, lightning protection, highly information-oriented society, low voltage distribution line, electric appliance, computer

EMCJ99-121 (2000-01)

A Pole-type Distribution Transformer Model for Electromagnetic Transient Studies

Taku Noda, Hiroshi Nakamoto*, and Shigeru Yokoyama


* Kyushu Electric Power Co.

2-11-1 Iwado-kita, Komae-shi, Tokyo 201-8511

*2-1-82 Watanabe-dori, Chuo-ku, Fukuoka-shi 810-8720

Abstract: This paper proposes a transient simulation model of pole-type distribution transformers for electromagnetic transient studies. The proposed model takes into account the following effects : (1) capacitance between windings and an enclosure and also between primary and secondary windings, (2) skin effects of winding conductors and an iron core, and (3) multiple resonance due to the combination of winding inductance and turn-to-turn capacitance. Thus, the model accurately reproduces the frequency characteristics of a pole-type distribution transformer in a wide range of frequency. The parameters of the model can easily be determined by frequency-characteristic measurements using an impedance analyzer. Because of the above capability, the proposed model enables the accurate evaluation of over-voltages on distribution lines including consumer-side over-voltages. In this paper, a 10-kVA pole-type distribution transformer is modeled, and the proposed model is validated by comparisons between simulated and laboratory-test results.

Key words: pole-type distribution transformer, transient studies, EMTP, consumer-side over-voltages


EMCJ99-122 (2000-01)

Environmental Magnetic Field in Office Building and Development of Magnetic Shieldings for CRT

Kiyotomi Miyajima, Kenichi Yamazaki, and Seietsu Tomita

Central Research Institute of Electric Power Industry

2-11-1, Iwado Kita, Komae-shi, Tokyo 201-8511 JAPAN

Abstract: Personal computer monitors and televisions with cathode ray tube (CRT) may have jitters in the alternating magnetic field. We measured magnetic fields in the office building that had jitters problems.

 In this report, a diurnal variation and distribution of the magnetic fields that have harmonics are showed. The occurrence mechanism of harmonics is explained. And, a new mitigation method of jitters by the compensation magnetic field is presented.

Key words: CRT, jitters, alternating magnetic field, magnetic shielding


EMCJ99-123 (2000-01)

Analysis of Electromagnetic Fields in the External Auditory Canal for Portable Telephones with a Helical Antenna

Jianqing Wang and Osamu Fujiwara

Department of Electrical and Computer Engineering, Nagoya Institute of Technology

Gokiso-cho, Showa-ku, Nagoya 466-8555 Japan

Abstract: A half-wave dipole antenna trends towards being adopted for the immunity test of medical devices for portable telephones from the viewpoint of operation efficiency. In this paper assuming the immunity test of hearing aids, we analyzed the electromagnetic fields in the external auditory canal for a portable telephone with a helical antenna using the finite-difference time-domain (FDTD) method, and compared the results with that for a half-wave dipole exposure. The helical antenna was modeled as a stack of dipoles and loops with an adequate relative weight according to Lazzi and Gandhi's proposal. The head model was developed from magnetic resonance imaging (MRI) data of a Japanese adult head. As a result, it was found both for the helical antenna and half-wave dipole that the electric field shows a standing-wave characteristic in the external auditory canal, while the magnetic field decreases gradually with deepening into the external auditory canal. The electric field around the entrance of' auditory canal for the helical antenna is stronger than that for the half-wave dipole, and vice-versa in the middle auditory canal. The magnetic field in the external auditory canal for the half-wave dipole is generally higher than that for the helical antenna.

Key words: portable telephone, immunity test, hearing aid, external auditory canal, FDTD analysis


EMCJ99-124 (2000-01)

Development of Electromagnetic Environment Design System for Private Wireless Communication System

Yuji MAEDA and Kazuhiro TAKAYA

NTT Lifestyle and Environmental Technology Laboratories

3-9-11 Midori-Cho, Musashino-Shi, Tokyo 180-8585 Japan

Abstract: Recently, several kinds of wireless communication systems such as 2.4-GHz-band wireless LANs and cordless phone are used in building and communication troubles due to electromagnetic interference are also increased. This report describes the electromagnetic environment design system, which was developed to design ideal electromagnetic environments where communication troubles were not occurred, for 2.4-GHz-band wireless LAN and cordless phone. This system simulates the electromagnetic interference and effect of building materials for electromagnetic propagation. It can provide an ideal arrangement of center stations of wireless systems and an ideal indoor or outdoor environment where wireless system are installed by estimating propagation characteristics and communication characteristics. The system configurations and two examples of actual design by using our system are introduced.

Key words: Electromagnetic environment, Private wireless system, Propagation, Ray tracing, Communication characteristics


EMCJ99-125 (2000-01)

A Theoretical Study on Analysis of TV Ghost Caused by the Super Highrise Tower and the Suppression of Reflected Wave Using the Wave Absorber

Takahiro Aoyagi, Yasutaka Shimizu, Toshio Saito*, and Kenichi Harakawa*

CRADLE, Tokyo Institute of Technology

*Research & Development Department, Takenaka Corporation

2-12-1 O-okayama, Meguro-ku, Tokyo 152-8552

*1-5-1 Ohtsuka, Inzai, Chiba 270-1395

Abstract: In this report, TV ghosts caused by the super highrise tower are theoretically analyzed at the viewpoint of DU ratio. The scattering wave from three type of the super high tower are calculated with taking account of distances between the transmission point, receive points and the tower. The effectiveness of the electromagnetic wave absorber is also considered when the absorber is put on the surface of the tower. As results in this report, the absorber of -10 dB reflection coefficient is enough characteristics for cylindrical model to vanish the TV ghost problem caused by the reflected wave. For X-shaped model and the eight column model, the absorber which has -15 dB characteristics is satisfying.

Key words: EMC, GMT, wave absorber, super highrise tower, TV ghost, scattering wave


EMCJ99-126 (2000-01)

Permittivity Measurement of Construction Materials in the Open Air

--- Numerical Analysis of the Measurement Accuracy ---

Shigemitsu Kaneko, Masatoshi Kubota, Michio Miyakawa*, Nozomu Ishii*, Yasushi Kanai**, and Tatsuhiko Saeki*

Graduate School of Science and Tech., Niigata Univ.

*Faculty of Eng., Niigata Univ.

**Faculty of Eng., Niigata Ins. of Tech.

Igarashi 2-8050, Niigata 950-2181 Japan

Department of Biocybernetics, Faculty of Eng., Niigata Univ.

Abstract: Effective use of electromagnetic waves (EM waves) in living spaces is realized by controlling the transmission characteristics of EM waves into the spaces. This can be done by choosing adequate construction materials and combining them as to have the desired transmission characteristics.

 To establish the design methodology, one must know the permittivity of construction materials. In this study, distribution of the standing wave is computed based on FD-TD method. From the observed distribution, complex permittivity of the construction materials has been estimated. The accuracy depends on the permittivity, thickness of the material and so on, but the error was smaller than approximately 1 %.

Key words: Construction materials / Electric property / Standing wave method / FD-TD method / Simulation


EMCJ99-127 (2000-01)

Shielding Effectiveness through Multilayered Materials with an Arbitrarily Located Electric Dipole

Yoshiyuki YOSHIMURA, Isamu NAGANO*, Hiroaki YOKOMOTO*, Toshio OOURA, and Satoshi YAGITANI*

Department of Machinery / Electronics, Industrial Research Institute of Ishikawa

* Department of Electrical and Computer Engineering, Kanazawa University

Ro-1, Tomizu-machi, Kanazawa 920-0223 JAPAN

*2-40-20 Kodatsuno, Kanazawa 920-8667 JAPAN

Abstract: We develop a method to evaluate the electromagnetic shielding effectiveness of a multilayered materials placed nearby an electric dipole source. The shielding effects are obtained in terms of a Sommerfeld integral, in which a spherical wave radiated from the dipole is expanded into a large number of cylindrical waves.

 The dipole source can be placed at any points with its axis either perpendicular or parallel to the material. In the far-field (high-frequency) limit the numerical results are in good agreement with a simple plane wave approximation, thus validating the present method. An air gap between the material layers is found to greatly improve its shielding effectiveness.

Key words: shielding effectiveness, dipole, multilayered materials, Sommerfeld integral


EMCJ99-128 (2000-01)

Transparent Thin Electromagnetic Wave Absorber for VHF Waves Composed of Divided Conductive Films

Toshio TSUNO

Department of Electrical Engineering, Toyama National College of Technology

13 Hongo-machi, Toyama-shi, Toyama-ken 939-8630 Japan

Abstract: Nearly one meter in thickness of the air is required to absorb VHF electromagnetic waves by using of a l/4 l type wave absorber (resistance-film /air /reflecting-film). Inserting the divided conductive films into the air layer, the thickness of the layer is reduced because of the huge real effective dielectric constant of the devided films. The effective dielectric constant with Coulomb interaction between stripe-like devided conductive films is calculated, and used to estimate the characteristics of the absorber. The panel of 10 cm in thickness can absorb waves of about 100MHz. The characteristics are mainly controlled by the width of the devided films and the air thickness between the devided films and the reflecting film, but little by the incident angle.

Key words: Electromagnetic wave absorber, VHF, Radio interference, Devided conductive film, Transparent conductive film, Window pane


EMCJ99-129 (2000-01)

Experimental Study on Manufacturing Magnetic Wood using Electromagnetic Wave Absorber in GHz Band

Koichi Narita and Hideo Oka

Graduate School of Electronic and Electronical Engineering, Iwate University

3-4-5, Ueda, Morioka 020-8551 Japan

Abstract : The purpose of this article is to examine the possibility of using magnetic wood as a woody electromagnetic absorber in GHz band. The results from measuring 4 types of different magnetic wood show that sandwich-type magnetic wood had good electromagnetic wave absorbing characteristics. This article covers experimental electromagnetic wave absorbing characteristics for sandwich-type magnetic wood under different parameters. The results showed that the 20mm thickness sandwich-type magnetic wood which was made with 40vol% mixture of Ni-Zn ferrite 400L with particle diameter of 600 mm over and 4mm layer of magnetics, could be used as a woody electromagnetic wave absorber under 1.93GHz.

Key words: electromagnetic wave absorber, magnetic wood, EMC, GHz band, magnetic powder, composite material