Osamu Fujiwara and Akira Sugiura

1. Conferences

1.1 Domestic Conferences and Meetings

On April 18, June 12 and July 28, the Technical Committee Meetings on EMC organized by IEICE in cooperation with URSI-E were held in Tokyo, Sapporo and Tokyo, respectively. The numbers of presented papers were 8, 9 and 9, respectively. On July 27, a special session for young engineers and students was held also in Tokyo, and 18 papers were presented.

1.2 International Conferences and Meetings

1. The 17th International Zurich Symposium on Electromagnetic Compatibility was held in Singapore, on February 28 – March 3, 2006. About 200 papers were presented at this symposium.

2. The 2nd Pan-Pacific EMC Joint Meeting (PPEMC’06) was held in Okayama, Japan, on May 25 and 26. 65 persons from five countries attended this meeting, and 20 papers were present.

3. The 18th International Wroclaw Symposium and Exhibition on Electromagnetic Compatibility was held in Wroclaw, on June 28 – 30, 2006. About 100 papers were presented at this symposium.

1.3 Future International Conferences and Meetings

1. The 4th Asia-Pacific Conference on Environmental Electromagnetics will be held in Dalian on August 1-4, 2006.

2. Progress in Electromagnetics Research Symposium (PIERS) 2006- Tokyo will be held in Tokyo, Japan, on August 2-5.

3. 2006 International Symposium on Electromagnetic Compatibility will be held in Portland, on August 13-17, 2006.

4. The 7th edition of EMC Europe Symposium will be held in Barcelona on September 4-8, 2006.

5. 2006 Korea-Japan AP/EMC/EMT Joint Conference (KJJC) will be held on September 23-24, 2006, Kanazawa, Japan.

2. Technical Trends

Method of Improving Signal Propagation Characteristics on AC Mains Lines

High-speed power line communication (PLC) system uses AC mains lines to transmit the signal. AC mains lines are not designed to transmit wide-band signals. Some studies have been performed to improve the transmission characteristics. One studied an adapter to be possible the signal propagation between 200V-line and 100V-line because AC mains system in Japan employed the single-phase three-wire system and this system could supply both 200V-line and 100V-line to a home. Another studied the propagation characteristics of the Factory-line being used to supply AC mains power in factories. This suggested that the impedance matching was important to improve the propagation characteristics. (Prof. N. Kuwabara)

Reverberation Chamber

Reverberation chambers are used for radiated emission and immunity testing. A reverberation chamber can create a multi-path environment by moving mechanical stirrers. When two antennas are placed opposite each other in an ideal reverberation chamber, the mean value of the complex received value equals the direct wave component between them because the vector sum of reflected waves with random phases is zero. Therefore, the free-space antenna factor can be determined from the mean value of the complex received value. A novel method was proposed in NICT for calibrating the EMI antenna using the statistical characteristics of the E-field in a reverberation chamber. The efficiency of the method has been confirmed. (Dr. Y Yamanaka)

Measurement and Analysis of HF Band Radio Noise

The noise figure and values of upper and lower deciles were calculated in NICT by the method of the recommendation ITU-R P.372-8 with observation data of radio noise in the high frequency band. The result showed that the calculated parameters of noise figure using quiet frequency bands, guard band of standard radio and radio astronomy band, are lager than those in recommendation, and the variance along frequency axis is large, too. Both the values of upper and lower deciles are smaller than those in recommendation, and the value of upper deciles is smaller than the lower one, contrary to the recommendation. (Dr. Y. Yamanaka, et al.)

Investigation of Emissions from Electrical Apparatuses Less Than 150 kHz

Emissions from electrical apparatuses have a possibility to disturb the operations of the watches using the standard frequencies. The magnetic field strength was measured for a fluorescent lamp and an electromagnetic cooker from 9 kHz to 150 kHz because Japan used the frequency of 40 kHz and 60 kHz as the standard frequency. The large loop antenna specified by CISPR 16-1 was used for the measurement. The results indicated that that the emissions from electrical apparatuses have a possibility to disturb the operation when these apparatuses were placed near the watches. (Prof. N. Kuwabara)

Magnetic Field Probe

Magnetic near field measurements of electronic devices are indispensable to establish techniques of evaluating and suppressing an electromagnetic interference. In Akita University, a high frequency carrier type magnetic field probe, which has high sensitivity and high resolution, called GMI (giant magneto-impedance) probe, was proposed. Its validity of magnetic near field measurements was demonstrated by comparing with a conventional shielded loop coil probe and numerical modeling. The GMI probe can clearly detect current concentration at an edge of a microstrip line, which allows high-resolution measurements. But, there is slight difference in the position of null points between measured and calculated results. (Prof. H. Inoue)

EMC Macro Model of LSI

The impedance determination of a linear equivalent circuit (LEC) in an EMC macro model, LECCS I/O was discussed in Okayama University. The 2-port LECCS I/O model, based on 2-port measurement by a vector network analyzer (VNA), was found to be affected by an external circuit connected to the input terminals of CMOS gates. To remove the defect, a 3-port LECCS I/O modelwith 3-port VNA was investigated. The 3-port model includes the input circuit of CMOS gates and the three ports of the model mean the power-supply terminal, the output terminal, and the input terminal to the ground terminal. The proposed 3-port model with 3-port VNA was used for power-ground impedance simulation by changing the impedances of external input and output circuits. As a result, the impedance simulation was in good agreement with measurements higher frequency range compared with the previous 2-port model with 2-port VNA. (Prof. R. Koga)

RFID EMI Testing

Radio Frequency Identification (RFID) systems have been attracting wide interest as essential devices for creating an IT oriented future society and they are expected to achieve various applications. Electromagnetic interference (EMI) from RFID reader/writers on medical devices is being investigated and ways to prevent this EMI are being discussed in Hokkaido University and the related associations. A newly developed experimental test system has been introduced and the basic design concept has been discussed. The EMI test experiments on 13 types of implantable pacemakers and defibrillators were carried out to validate the fundamental performance of the test system The aim of the research is to establish an EMI estimation method using FDTD analysis and a measurement system to obtain precise and detailed EMI characteristics regarding RFID EMI on medical devices. (Prof. T. Nojima)

ESD Immunity Testing

The electromagnetic (EM) noise caused by electrostatic discharge (ESD) events due to charged metals is a major source of malfunction to high-tech equipment. Especially, electronic devices and equipment for vehicles are being used in strict EM environment, and there is a tendency for high-tech equipment to increase also in cars. However, single-sided printed circuit boards (PCBs) are still used for that electronic equipment due to simplified fabrication and low production costs. The PCBs of this kind is said to have some immunity to EM noises so far, while its mechanism has remain unknown. The ESD immunity testing is being specified in the IEC61000-4-2, which prescribes the current waveform from an ESD-gun. With an FDTD model of the ESD-gun, Prof. Fujiwara et al. in Nagoya Institute of Technology simulated the induced voltage in a signal trace fabricated on a single-sided PCB together with magnetic near-field. As a result, it was found that there were some discrepancies between simulated and measured voltages induced in the trace despite good agreement between simulation and measurement of the magnetic near-field when the ESD-gun was placed close to the trace, and that fair agreement was observed in simulated and measured induced voltage waveforms when the ESD-gun was rotated so as to be away from the trace. These findings suggest that the induced voltages may be caused by the injected discharge current and the electric coupling between the trace and the EM valve installed in the ESD-gun, and that the simulation problem in this case is due to lack of FDTD modeling corresponding to the EM valve. (Prof. O. Fujiwara)

UWB Interference

Ultra Wide Band (UWB) is a wireless system with a bandwidth of several GHz, which transmits data with a low power spectrum density, and enables a high-speed transmission speed of 100M-480Mbps. However, a dedicated frequency cannot be allocated for UWB system because the UWB bandwidth is very wide. Therefore, the electromagnetic field of UWB systems may interfere with other wireless communication systems. The experiment on interference by UWB to wireless LAN IEEE 802.11a was examined by using a GTEM cell in Musashi Institute of Technology and NICT. This method can be used for the antenna all-in-one W-LAN terminal. (Prof. M. Tokuda)

Transmission Characteristics of UWB System Using Inside of Human Body

UWB (Ultra wide band) system is developed as a high-speed communication system in a short distance. Transmission characteristics of UWB system was investigated theoretically when the system communicated between neighborhood outside of human body and inside of human body. The results indicated that the system could be communicated by a sufficient quality even if the influence of the body is considered. (Prof. N. Kuwabara)

SA Calculation Method for UWB Signals

UWB is a promising candidate for wireless on-body area networking and wireless intra-body communications, because of its advantages such as low power, low profile, high speed and high security. However, the specific energy absorption (SA) and specific absorption rate (SAR) evaluation in the human body is an important task in the system design from the EMC point of view. In this study, three SA calculation methods, derived based on the Debye approximations of biological tissue properties, were investigated numerically for their effectiveness. An application of SA calculation for on-body area UWB transmission was also given. The result showed that the SA is much smaller than the safety limits Under the FCC UWB power spectrum mask limits. (Prof. J. Wang)