EMCABS EMC Abstracts Osamu Fujiwara, Associate Editor

EMCABS: 01-5-2002

Reduction of Crosstalk Noise in Modular Jack for High-Speed Differential Signal Interconnection

Nanhoom Kim+, Myunghee Sung+, Hyungsoo Kim+, Seungyong Baek+, Woonghwan Ryu+, Jeong-Gyun An++, and Joungho Kim+
+Terahertz Media and System Lab., Division of Electrical Engineering and Computer Science, Korean Advanced Institute of Science and Technology, Taejon 305-701, Korea
++Korea Telecommunication, Taejeon 305-811, Korea
IEEE Transactions on Advanced Packaging, Vol. 24, No. 3, August 2001, pp. 260-267

Abstract: Much of the near-end-crosstalk in unshielded twisted-pair (UTP) cable is due to capacitive coupling in the standard CAT-5E modular jack where the conductors are not twisted. This paper describes the use of capacitors formed on the PCB of the modular jack to compensate the unbalanced capacitive crosstalk that occurs in the plug and insert of the modular jack. The design of the embedded capacitors is presented along with results of measurements. Both emissions immunity of the cable system are improved.

Index terms: Crosstalk noise, CAT-5E modular jack, differential signal transmission in unshielded twisted pair (UTP) cable, UTP cable terminations.

EMCABS: 02-5-2002

A Novel Technique to Achieve Unity Power Factor and Fast Transient Response in AC-to-DC Converters

Zaohong Yang+ and Paresh C. Sen++
+Tyco Electronics Power Systems, Mesquite, TX 75149 USA,
++ Department of Electrical and Computer Engineering, Queen's University, Kingston, ON K7L 3N6 Canada
IEEE Transactions on Power Electronics, Vol. 16, No. 6, November, 2001, pp. 764-775

Abstract: Power factor correction (PFC) circuits for converters frequently result in poor transient response. This circuit uses the diode current to develop a control signal for a voltage feedback loop to provide better transient response than similar PFC circuits. Simulation and experimental results confirm the improved performance of the converter which achieves a PF of 0.999 and a total harmonic distortion (THD) of 1.96%.

Index terms: Switch mode rectifier, PFC converter, fast transient response.

EMCABS: 03-5-2002

Interlaboratory comparison of radiated emission measurements using a spherical dipole radiator

T.-W. Kang, Y.-C. Chung+, S.-H.Won+ and H.-T. Kim++
+Electromagnetic Compatibility Group, Division of Electromagnetic Metrology, Korea Research Institute of Standards and Science, PO Box 102, Yusong Taejon 305-600. Korea
++Department of Electrical Engineering, Pohang University of Science and Technology, Pohang, Kyungbuk 790-330, Korea
IEE Proceedings, SCIENCE, MEASUREMENT AND TECHNOLOGY, Vol. 148, Number 1, January 2001, pp. 35-40

Abstract: EMC laboratory accreditation requires inter-laboratory comparisons and the determination of the applicable measurement uncertainties. In the study reported, the uncertainties are determined for three parts: the transmitting part, the OATS itself, and the receiving part for twelve 10-meter sites. Table 2 summarizes the measurement uncertainties for a specific OATS. The analyses presented here indicate the major sources of uncertainty are the antenna factor calibration, mismatch, the site imperfections and the receiver performance.

Index terms: Radiated emission (RE) measurement uncertainty, inter-laboratory comparisons and accreditations, spherical dipole radiator (SDR) as reference emitter, sources of uncertainty in OATS.

EMCABS: 04-5-2002

Simulation of normalized site attenuation measurement using biconi-log antennas

Katsumi Fujii+, Atsuo Senga+, and Takashi Iwasaki+
+Dept. of Electronic Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu-shi, 182-8585 Japan
The Transactions of the Institute of Electronics, Information and Communication Engineers B, Vol. J84-B, No. 2, 2001, pp. 272-282.

Abstract: Normalized site attenuation (NSA) using a pair of biconi-log antennas is calculated in horizontal and vertical polarizations using the method of moment. The calculated results are confirmed by a comparison with experimental results. It is found that the radiation patterns, the positions of active antenna elements, the height dependency of antenna factors, and near field effects have influence on the difference in NSA between the measurement values in CISPR 16. From these results, it is concluded that correction for the biconi-log antennas is difficult in the NSA model.

Index terms: Biconi-log antennas, normalized site attenuation, moment method, antenna factor

EMCABS: 05-5-2002

Suppression of field on power lines induced by medium wave broadcasting wave by loading inductance

Takayuki Sasamori+, Kunio Sawaya++, saburo Adachi+++, Yasuhito Murai++++, Massahiro Ogawa++++, Katsuhiro Iguchi+++++, and Mitsuo Nishiyama+++++
+Dept. of Electronics and Information Systems, Faculty of Systems Science and Technology, Akita Prefectual University, Honjo-shi, 015-0055 Japan
++Graduate School of Engineering, Tohoku University, Sendai-shi, 980-8579 Japan
+++Dept. of Communication Engineering, Tohoku Institute of Technology, Sendai-shi, 982-8577 Japan
++++Tokyo Electric Power Co. Ltd., Kasukabe-shi, 344-0054 Japan
+++++Kandenko Co. Ltd., Tokyo, 108-8533 Japan
The Transactions of the Institute of Electronics, Information and Communication Engineers B, Vol. J84-B, No. 2, 2001, pp. 283-290.

Abstract: It has been known hitherto that a very strong electromagnetic field is induced occasionally along aerial power lines located near a MF broadcasting station, and thus the construction and maintenance of power lines are sometimes endangered. In this paper the induced electric field strength near the power lines is analyzed by using the moment method, and is compared with the measured values. It is shown that the loading of appropriate inductance coils is very effective to suppress the induced electric field, and accordingly to avoid the danger induced.

Index terms: Moment method, power line, broadcasting wave, induced field, inductance

EMCABS: 06-5-2002

Electromagnetic noise induced on unshielded twisted pair cable

Naoki Yamamoto+, Yoshifumi Shimoshio+, Hiroaki Koga+, and Masamitsu Tokuda++
+Dept. of Information and Communication Engineering Kumamoto National College of Technology, 2659-2 Suya, Nishigoshi-machi, Kikuchi-gun, Kumamoto-ken, 861-1102 Japan
++Dept. of Electrical Engineering, Kyushu Institute of Technology, 1-1 Sensui, Tobata-ku, Kitakyushu-shi, 804-8550 Japan
The Transactions of the Institute of Electronics, Information and Communication Engineers B, Vol. J84-B, No. 3, 2001, pp. 551-561.

Abstract: This paper describes an inducing mechanism of the electromagnetic noise between a single inducing wire above ground and an unshielded twisted pair cable above ground. A twisted pair cable consists of winding wires on a wooden cylindrical bar. An inducing wire is placed near the twisted pair cable. A calculation method is derived using chain matrices for the induced voltage on the twisted pair cable. The paper shows the electromagnetic noise characteristics for a pitch, inducing wire position, cable height and terminal impedance theoretically and experimentally. It has confirmed that the experimental values agree well with the theoretical values.

Index terms: Twisted pair cable, induced voltage, pitch, inductive coupling, capacitive coupling.

EMCABS: 07-5-2002

An immunity testing cell using a rectangular resonator consisting of a conducting channel plate and a capacitive gap

Masahiro Saito+, Kenji Saegusa+, and Nozomu Hasebe+
+College of Science and Technology, Nihon University, Funabashi-shi, 274-8501 Japan
The Transactions of the Institute of Electronics, Information and Communication Engineers B, Vol. J84-B, No. 7, 2001, pp. 1365-1372.

Abstract: In this paper, an immunity testing cell using a rectangular loop resonator is proposed. The resonator consists of a conducting channel plate and a capacitive gap set onto the ground plane. The cell has a size of 1/10 wavelength at the testing frequency. The electric and magnetic field distribution inside the cells of two types are analyzed by the FDTD method, and the results are compared with the experimental results. A close agreement is obtained between both results. The electric field strength inside the two types of cells is increased 31.2 dB and 14.3 dB, respectively, when compared with the field strength inside a TEM cell of the same size. The latter type of resonator yields an amplitude deviation of 2 dB inside a square area of 100 mm length. The resonator, when covered by a shield case for practical use, shows an increase in the electric field strength of 11.2 dB over the level of the same size TEM cell. The amplitude deviation remains the same as that of the resonator without the shield case.

Index terms: Resonator, immunity, TEM cell, FDTD method

EMCABS: 08-5-2002

A system detecting malfunction areas with esd simulator for pcbs

Hiroshi Onomae+ and Yoji Nagasawa++
+Kagoshima Prefectural Institute of Inductrial Technology, Hayato-cho, Aire-gun, Kagoshima-ken, 899-5105 Japan
++Faculty of Engineering, Kagoshima University, Kagoshima-shi, 890-0065 Japan
The Transactions of the Institute of Electronics, Information and Communication Engineers B, Vol. J84-B, No. 8, 2001, pp. 1514-1522.

Abstract: In order to evaluate immunity levels during an Electrostatic Discharge (ESD) test for electronic equipment, a high efficiency detecting system for malfunction areas on printed circuit boards (PCBs) was developed. A small conductor board connected to an ESD gun was faced close to a PCB, and then local electromagnetic waves were injected to the PCB. In order to search low immunity level areas efficiently, three conductor boards (9x9cm, 3x3cm and 1x1cm) were used stepwise to narrow the electromagnetic waves injection area. In this article, influence of the size of the conductor board, experimental confirmation for narrowing the range of electromagnetic waves by changing the conductor board size, and the validity of the method for real electronic equipment were described. The induced voltage wave was slightly varied in the waveform and the peak voltage level by the conductor board size when a micro-strip line was tested in the EUT. However, the induced voltage levels of each conductor board had a direct proportion to the set voltage of the ESD simulator. When the conducting line in the EUT overlapped to the conductor board, very strong coupling was observed compared with the other areas. In the proof test of the equipment on the market, several malfunction causes were made clear, and there was a correlation between these results and results of an international standard examination (IEC61000-4-2).

Index terms: ESD, immunity, printed circuit board, malfunction.

EMCABS: 09-5-2002

Effectiveness evaluation of shielding material for reducing electromagnetic interference of cardiac pacemaker induced by portable information terminals

Jianqing Wang+, Takeshi Ohshima+ and Osamu Fujiwara+
+Dept. of Electrical and Computer Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya-shi, 466-8555 Japan
The Transactions of the Institute of Electronics, Information and Communication Engineers B, Vol. J84-B, No. 10, 2001, pp. 1829-1833.

Abstract: A shielding technique is an effective means to protect implanted cardiac pacemaker users from portable information terminals, whereas no evaluation methods for this aim have been established. In this paper, and FDTD model for predicting EMI levels in the pacemakers was introduced for numerical shield effectiveness evaluation. In the model, the pacemaker acted as a receiving antenna and the open-voltage at the pacemaker connector proved to be an appropriate index for EMI level prediction. With this model the effectiveness of a magnetic rubber sheet and a resistive film were evaluated for reducing the EMI level in the pacemakers by portable information terminals. The results have shown that the resistive film has an excellent shielding effect so that even if the distance between the antenna and the human body is as close as 1.5 cm, the resistive film enables one to secure the effective distance longer than the 22 cm being specified in the guideline of the Pacemaker Committee of Japan.

Index terms: Portable information terminal, cardiac pacemaker, electromagnetic interference, shield, FDTD analysis.

EMCABS: 10-5-2002

Analysis for the suppression of coupling between two microstrip lines in microwave amplifier modules by lossy magnetic material loading

Akihiko Saito+ and Atsuhiro Nishikata++
+Daido Steel Co. Ltd., 2-30 Daido-cho, Minami-ku, Nagoya-shi, 457-8545 Japan
++Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku Tokyo, 152-8552 Japan
The Transactions of the Institute of Electronics, Information and Communication Engineers B, Vol. J84-B, No. 10, 2001, pp. 1834-1840.

Abstract: In manufacturing the microwave amplifier module, the problem of coupling between input and output circuits inside the metal case is a serious topic. For the reduction of the coupling, putting a lossy magnetic composite material beneath the upper cover is known to be effective. To theoretically explain the decoupling mechanism by this method, we derived the coupling formula between two micro-strip lines in the metal case. For the formulation, the coupling model of the trilayer waveguide's fundamental mode and the micro-strip lines were introduced. For the experiment, the composite material sheet made from soft magnetic metal powder and rubber was applied. The numerical result based on the formula agreed well with the experimental result, which supported the validity of the formula.

Index terms: Microwave amplifier module, characteristics improvement, lossy magnetic material, micro-strip line, decoupling effect, EMC.

EMCABS: 11-5-2002

A method to reduce electromagnetic noise caused by arc discharge of ag-pd electrical contacts in terms of thermal factor

Yasuo Ebara+, Hideaki Aone++, and Yoshiaki Nemoto++
+Deta Processing Center, Kyoto University, Yoshidahoncho, Sakyo-ku Kyoto-shi, 606-8501 Japan
++Graduate School of Information Sciences, Tohoku University, Aramaki-Aza-Aoba 05, Aoba-ku, Sendai-shi, 980-8579 Japan
The Transactions of the Institute of Electronics, Information and Communication Engineers B, Vol. J84-B, No. 12, 2001, pp. 2367-2373.

Abstract: The authors proposed the method to reduce electromagnetic noise (frequency 5 MHz) caused by arc discharge in Ag-Pd electrical contacts (circuit condition; DC48 V, 4 A). In opening electrodes, continuous burst noise is generated in the whole period of arc discharge, and high and low periods of noise level were observed in the noise waveform. First, it was confirmed that the duration of whole burst noise could be reduced by improving the thermal condition of the electrode using a large-diameter Ag electrode. Next, the authors analyzed statistically on relationship the division of periods by feature of arc voltage and noise waveforms for discussion on noise reduction. With these results, it was shown that the larger the diameter of Ag electrode was, the shorter the duration of high-noise level period became. In this paper, the authors showed a fundamental technique to reduce electromagnetic noise by the design of electrode in consideration of thermal factor.

Index terms: Electric contact, arc discharge, electromagnetic noise, electrode diameter, thermal factor.

EMCABS: 12-5-2002

Calculation of electric far-field radiated from transmission line attached to a ferrite core above a ground plane

Tetsuya Maekawa+ and Osamu Fujiwara+
+Faculty of Engineering, Nagoya Institute of Technology, Nagoya-shi, 466-8555 Japan
The Transactions of the Institute of Electronics, Information and Communication Engineers B, Vol. J84-B, No. 12, 2001, pp. 2374-2381.

Abstract: Magnetic materials are often used as a means to reduce the electromagnetic (EM) noise on the source side and also improve the immunity against the EM noise on the device side. Effects on the suppression of the EM noise from printed circuit board (PCB) traces and cables are being investigated. In this paper, we first derived a formula for calculating the far-field level radiated from a ferrite-core-attached transmission-line above a ground plane, and then numerically investigated the effect of the ferrite core attachment on the suppression of the radiated far-field. As a result, we found that the radiated field level is proportional to the spatial average value of the current distribution along the line, and its suppression directly contributes to the reduction of radiated field level. Moreover, we also found that the attachment of a ferrite core to the near-end of the line results in a suppression of the radiated field, while the attachment of ferrite core to the far-end of the line results in an increase of the radiated field.

Index terms: Transmission line, ferrite core, electric far-field, suppression effect. EMC

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