EMCABS EMC Abstracts Osamu Fujiwara, Associate Editor

EMCABS: 01-2-2002

CORRELATION OF TEST FACILITIES FOR RADIATED EMISSION MEASUREMENTS USING A SPHERICAL DIPOLE RADIATOR: OATS, FULLY ANECHOIC CHAMBER AND GTEM CELL

Tae-Weon Kang+, Joo-Gwang Lee+ and Hyo-Tae Kim++
+Electromagnetics Group, Division of Electromagnetic Metrology, Korea Research Institute of Standards and Science, P. O. Box 102, Yusong, Taejon 305-600, Republic of Korea
++Department of Electrical Engineering, Pohand University of Science and Technology, Pohang, Kyoungbuk 790-784, Republic of Korea
Proceedings of Korea-Japan AP/EMC/EMT Joint Conference, Taejon, Korea, September 10-11, 2001, pp.98-102.

Abstract: The correlation of test facilities for radiated emission measurements are considered in the frequency range of 30 to 1000 MHz. The facilities considered are an open area test site (OATS), a fully anechoic chamber (FAC) and a gigahertz-TEM (GTEM) cell, and only vertically polarized case is taken into account. A spherical dipole radiator (SDR) is employed as a reference emitter. Results show that the correlation of the three test facilities agrees within +-4.7 dB and +-5.7 dB for 3 m and 10 m distances, respectively.

Index terms: Correlation, radiated emission, open area test site, GTEM cell, fully anechoic chamber.

EMCABS: 02-2-2002

SAR REDUCED EFFECT OF THE FERRITE BEAD INSIDE OF THE CULLULAR PHONE ANGENNA

Yun'n M'young Gimm, Ki Hwea Kim and Seung Bae Lee
Dept. of Electronics Engineering, Dankook University
Proceedings of Korea-Japan AP/EMC/EMT Joint Conference, Taejon, Korea, September 10-11, 2001, pp.200-205.

Abstract: We are proposing a new mobile phone antenna, which has a specially manufactured Mn-Zn cylindrical ferrite bead inside of the helical coil of the antenna. The extended antenna radiation patterns and the spatial peak SAR averaged over 1 gram simulated tissue with and without the ferrite bead insertion were measured at 824 MHz. The results show that the ferrite bead resulted in a SAR reduction of about 20%, and a reflection coefficient increase of about 7% for the extended antenna. The applicability of this scheme to the antenna mass production is quite feasible.
Index terms: Mobile phone, antenna, ferrite bead, SAR reduction.

EMCABS: 03-2-2002

RESOLUTION IMPROVEMENT OF E-FIELD PROBE USING A SIGNAL PROCESSING TECHNIQUE

Hiroshi Hirayama and Yoshio Kami
The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu-shi, Tokyo 182-8585, Japan
Proceedings of Korea-Japan AP/EMC/EMT Joint Conference, Taejon, Korea, September 10-11, 2001, pp.206-209.

Abstract: This report describes a new method to improve resolution of an E-field probe with a signal processing technique without hardware modification. In order to reduce an emission from a PCB, for example, it is useful to study near field distribution. Most conventional methods have obtained the distribution of E-field strength by scanning an E-field probe [1] and multiplying its antenna factor by the output voltage. However, the method has the following disadvantages: 1) a correlation between near E/M field distribution and the probe output voltage has not been proved, 2) not enough resolution for a latest small schematic can be obtained. In this report, we propose a new method, which makes it possible to overcome these problems by using a de-convolution technique with E-probe's spatial responses. Experimental results show that the proposed method has a capability to distinguish two near null points, which cannot be separated with a conventional method.
Index terms: Convolution, model for E-field, measurement and de-convolution.

EMCABS: 04-2-2002

EFFECT OF GROUNDING ON LIGHTNING-INDUCED VOLTAGES OF TELECOMMUNICATION SUBSCRIBER CABLE

Jae Cheol Ju+ and Dong Chul Park++
+Dept. of Electronic Eng., Chungnam Nat'l Univ., Daejeon, Korea
++Dept. of Radio Science and Eng., Chungnam Nat'l Univ., Daejeon, Korea
Proceedings of Korea-Japan AP/EMC/EMT Joint Conference, Taejon, Korea, September 10-11, 2001, pp.210-213.

Abstract: The lightning-induced voltages on a telecommunication subscriber cable with multipoint grounding both on a cable shield and on an overhead ground wire are discussed. The shielding effectiveness due to multipoint grounding is affected by ground position, cable length, grounding resistance, and amplitude and wave shapes of lightning electromagnetic fields. In this paper, the characteristics of lightning-induced voltages between cable shield and twisted-pair wires inside are calculated by using the FDTD method. The shielding effect by changing the grounding position of the cable shield and the overhead ground wire is also examined. A finitely conducting ground plane is taken into account in both lightning electromagnetic field calculations and surge propagation along the cable shield for a practical simulation.
Index terms: Telecommunication subscriber cable, lightning-induced voltage, grounding effect, FDTD analysis.

EMCABS: 05-2-2002

DEVELOPMENT OF WIDE-BAND FERRITE FIN ELECTROMAGNETIC WAVE ABSORVER PANEL WITH VARIOUS SURFACE LAYERS

Toshihiro Yamane+, Shigeo Numata+, Tetsuya Mizumoto++ and Yoshiyuki Naito++
+Shimizu Corporation, Engineering R&D Department, Institute of Technology, 3-4-17, Etchujima, Koto-ku, Tokyo 135-8530, Japan
++Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-0033, Japan
Proceedings of Korea-Japan AP/EMC/EMT Joint Conference, Taejon, Korea, September 10-11, 2001, pp.234-237.

Abstract: In Japan, television ghost caused by tall buildings becomes a problem to be solved [1]. The area where severe ghost is observed can be remarkably reduced by suppressing reflection due to the building walls <-14dB [2]. Most absorbers currently used are narrow band types for either VHF or UHF band. Absorbers are expected to suppress reflection in a wide frequency range, since both VHF and UHF bands are used for TV broadcasting in Japanese urban area. We have developed single layer ferrite grid absorbers as wide band absorbers, which are often used in RF anechoic chambers [3]. The grid absorber works for both vertically and horizontally polarized waves. Vertical fin structure is sufficient to absorb a horizontally polarized wave [4], which is often used as a TV broadcasting radio wave in the Japanese urban area. In this paper, the ferrite fin structure is used for an absorber on the TV ghost problem. For tall building walls, PC (Precast Concrete) curtain walls are often used to shorten the construction period. The PC curtain walls consist of the building materials. This paper describes development of a wide band absorber panel as a PC curtain wall using the ferrite fin with various surface layers. The absorber panels are designed by taking into account building materials located in front of the ferrite fin. The characteristics are measured using mock-ups of the absorber panel.
Index terms: TV ghost problem, electromagnetic wave absorber, ferrite fin absorber panel, measurement.

EMCABS: 06-2-2002

DESIGN OF CUTTING CONE SHAPED AND HEMISPHERE SHAPE-ADDED FERRITE ABSORBER

Dong Il Kim, June Young Son and Jae Young Bae
Dept. of Radio Sciences & Engineering, Korea Maritime University
Proceedings of Korea-Japan AP/EMC/EMT Joint Conference, Taejon, Korea, September 10-11, 2001, pp.238-241.

Abstract: Due to the progress of the electronic industry and radio communication technologies, mankind enjoys an abundant life. On the other hand, serious social problems such as EMI by unnecessary electromagnetic (EM) waves occur due to the increased use of electromagnetic waves. Therefore, the organizations such as CISPR, FCC, ANSI, etc., have provided the standard of the EM wave environment for the countermeasure of the EMC. The absorption ability of EM wave absorber has required more than 20 dB, and the bandwidth has been required through 30 MHz to 1,000 MHz for satisfying the international standards about an anechoic chamber for EMI/EMS measurement. From November of 1998, however, CISPR has accepted the extended frequency band from 1 GHz to 18 GHz additionally in the bandwidth of EMI measurement [1]. In this paper, we proposed the hemisphere shape-added absorber on the cutting cone-shape in order to satisfy the above requirements and carried out broadband design using the equivalent material constants method. Furthermore, the experiments were carried out over the frequency band from 30 MHz to 3 GHz, and the validity of the proposed design theory was confirmed.
Index terms: EMI measurement, cutting cone shaped and hemisphere shape-added ferrite absorber, broadband design, experiment.

EMCABS: 07-2-2002

AN EXPERIMENTAL STUDY OF A LAMBDA/4 WAVE ABSORBER USING FSS FOR TWO FREQUENCIES

Akihiko Itou+, Kouji Wada++ and Osamu Hashimoto++
+Technical Research Institute, TOPPAN PRINTING CO., LTD., 4-2-3 Takanodai-minami, Sugito-machi, Kita-katushika-gun, Saitama 345-8508, Japan
++College of Science and Engineering, Aoyama Gakuin University, 6-16-1 Chitosedai, Setagaya-ku, Tokyo 157-8572, Japan
Proceedings of Korea-Japan AP/EMC/EMT Joint Conference, Taejon, Korea, September 10-11, 2001, pp.242-245.

Abstract: Technologies of a frequency selective surface (FSS) are of considerable practical concern for good frequency-selection in recent complicated frequency bands [1]. We previously studied basic characteristics of the FSS and their application to a single-layer lambda/4 wave absorber. To the author's knowledge, there are no studies of the lambda/4 wave absorber using the FSS for consisting of the reflection film. We consider that the shielding characteristics with the frequency-selection of the presented wave absorber can be obtained as well as the realization of the absorption characteristics with the frequency selection [2]. First, basic operations of the FSS are examined experimentally. Second, a lambda/4 wave absorber using the FSS is proposed, fabricated and measured. In this study, two types of new wave absorbers using the FSS are proposed, which are fabricated by double absorption films and double FSS films, respectively. Moreover, the design of the double absorption films type wave absorber can be performed by point matching method. As for the design of the double FSS films type wave absorber, the classical design of the single-layer absorber is applied.
Index terms: Electromagnetic wave absorber, frequency selective surface (FSS), lambda/4 wave FSS absorber, measurement.

EMCABS: 08-2-2002

RADIO ELECTRO-MAGNETIC COMPATIBILITY AND APPLICATION OF HIGH-TC SUPERCONDUCTING TECHNOLOGY

Toshio Nojima, Yoshiaki Tarusawa and Shoichi Narahashi
Radio Environment Technology Research Laboratories, NTTDoCoMo Inc., 3-5 Hikarino-oka, Yokosuka-shi, 239-8536, Japan
Proceedings of 2001 Asia-Pacific Microwave Conference, Taipei, Taiwan, December 3-6, 2001, pp.1000-1003.

Abstract: Recent research and development activities on measurement technologies and countermeasures for establishing the electromagnetic compatibility (EMC) of mobile radio equipment with electronic devices and biological safety issues are introduced. EMC studies of medical devices are focused on, and SAR measurement technologies for mobile radios are discussed. Moreover, a cryogenic receiver front end using high temperature super-conducting filter for mobile base stations is proposed as a promising technology that allows the transmission power of mobile communication systems to be lowered, a desirable result with regard to EMC.
Index terms: EMC, mobile radio equipment, medical devices, SAR measurement, high temperature super-conducting filter.

EMCABS: 09-2-2002

A SIMPLE METHOD FOR PREDICTING COMMON-MODE RADIATION FROM A CABLE ATTACHED TO A CONDUCTING ENCLOSURE

Jianqing Wang+, Osamu Fujiwara+ and Kohji Sasabe++
+Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
++Matsushita Electric Works, Ltd., 1048, Kadoma, Osaka 571-8686, Japan
Proceedings of 2001 Asia-Pacific Microwave Conference, Taipei, Taiwan, December 3-6, 2001, pp.1119-1122.

Abstract: Common-mode (CM) radiation from a cable attached to a conducting enclosure is typically a dipole-type antenna structure, in which an equivalent noise voltage source located at the connector excites the attached cable against the enclosure to produce radiated emissions. A simple method for predicting the CM radiation from the cable/enclosure structure was proposed in this paper. The method combines an equivalent dipole approximation with sinusoidal current distribution and CM current measurement at a specified location on the cable. The predicted resonance frequencies and CM radiation levels were validated with engineering accuracy, i.e., within 30 MHz and 6 dB, respectively, from the measured and FDTD-modeled results in the frequencies above 130 MHz.
Index terms: Conducting enclosure, attached cable, common-mode radiation, prediction, equivalent dipole approximation, FDTD calculation, measurement.

EMCABS: 10-2-2002

AN IMPROVEMENT OF FIELD UNIFORMITY OF REVERBERATION CHAMBER BY THE VARIANCE OF DIFFUSER VOLUME RATIO

Jong-Chel Yun, Joong-Geun Rhee, Ph. D. and Sam-Young Chung
Dept. of Electronic Eng. Hanyang University
Proceedings of 2001 Asia-Pacific Microwave Conference, Taipei, Taiwan, December 3-6, 2001, pp.1119-1122.

Abstract: A conventional reverberation chamber is a rectangular structure including mode-stirrers or mode-tuned stirrers to obtain the field uniformity inside the chamber. In this paper, we used Schroeder diffusers to obtain field uniformity of a rectangular reverberation chamber, and field uniformity characteristics were investigated with the condition of a diffuser volume ratio of 0.9, 1.35, and 1.8 % of the total rectangular empty volume. The Finite-Difference Time-Domain (FDTD) simulation method was used to analyze the field homogeneous characteristics of these reverberation chambers.
Index terms: Reverberation chamber, field uniformity, Schroeder diffusers, FDTD simulation.

EMCABS: 11-2-2002

COMPOSITE EFFECTS OF REFLECTIONS AND GROUND BOUNCE FOR SIGNAL VIAS IN MULTI-LAYER ENVIRONMENT

Sheng-Mou Lin and Ruey-Beei Wu
Dept. of Electrical Engineering and Graduate Institute of Communication Engineering, National Taiwan University, Taipei, Taiwan, 10617, R.O.C.
Proceedings of 2001 Asia-Pacific Microwave Conference, Taipei, Taiwan, December 3-6, 2001, pp.1127-1130.

Abstract: The signal propagating down the vias in a multi-layer environment will suffer from composite effects of reflected noise by via discontinuity and ground bounce between power/ground planes. An equivalent circuit modeling is proposed to simulate these effects, which consists of transmission line for signal line, lumped inductance and capacitance for via discontinuity, and two-dimensional fields solver for the region between power and ground planes. Simulations are performed for a four-layer structure and three different cases are considered to characterize both effects. Results show that the via discontinuity is dominant for reflected noise in the early time response, while the ground bounce is dominant in the late time response.
Index terms: Multi-layer environment, via, ground bounce, equivalent circuit modeling, simulation.

EMCABS: 12-2-2002

EMI INDUCED BY THE SIMULTANEOUS SWITCHING NOISE ON THE PARTITIONED DC PLANES

J. N. Hwang, J. J. Lin and Tzong-Lin Wu
EMC Laboratory, Department of Electrical Engineering, National Sun Yat-sen University, Kaohsiung 804, Taiwan
Proceedings of 2001 Asia-Pacific Microwave Conference, Taipei, Taiwan, December 3-6, 2001, pp.1135-1138.

Abstract: Based on the FDTD modeling approach, the bridging effect of the isolation moat on the EMI caused by simultaneous switching noise is investigated. We find that isolating the noise source by the slits (or moats) is effective to eliminate the EMI, but bridges connecting between two sides of the slits will significantly degrade the effect of EMI protection. The measured and modeled results of the EMI strength at 3m are compared and they are quite consistent.
Index terms: Switching noise, EMI, partitioned DC planes, isolation moat, FDTD modeling, measurement.

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