Commission E (Electromagnetic Noise and Interference)

Activity Report (August 2004`November 2004)

 

November 15, 2004

Osamu Fujiwara and Akira Sugiura

 

1.     Conferences

1.1 Domestic Conferences and Meetings

On October 1st, and October 28 – 29, the technical committee meetings on EMC organized by IEICE in cooperation with URSI-E were held at Keihanna Human Info-Communication Research Center and Iwate University, respectively. The numbers of presented papers were 15 and 32, respectively.      

 

1.2 International Conferences and Meetings

 

1. 1st Annual meeting of Asia Oceania Geosciences Society has been held in Singapore, form July 5 to 9, 2004. A session of "Seismo-electromagnetics" has been organized and 17 reports were presented.

2. 2004 IEEE International Symposium on Electromagnetic Compatibility was held in Santa Clara, USA, from August 9 to 13, 2004. More than 200 papers were presented at the symposium.

3. 2004 Asia-Pacific Radio Science Conference (AP-RASCf04) was held in Qingdao, China, from August 24 to 27, 2004. Four Special Sessions were organized by Commission E, in which one was a Joint Session in cooperation with Chinese Commission K. About 180 people attended the conference, and nearly 40% in which were from Japan.

4. The International Symposium on Electromagnetic Compatibility, EMC Europe 2004, was held in Eindhoven, The Netherlands, from September 6 to 10, 2004. More than 300 people attended the symposium, and 178 papers, in which 19 papers were from Japan, were presented.

5. 33rd Symposium on Electromagnetics Theory has been held in Awaji Yumebutai International Conference Center, Japan. There are 5 papers associated with natural electromagnetic phenomena.

 

1.3 Future International Conferences and Meetings

1.  2004 Korea-Japan AP/EMC/EMT Joint Conference (KJJC-AP/EMC/EMT'04) will be held in Seoul, Korea, on November 22-23, 2004. 

3.      16th International Zurich Symposium on Electromagnetic Compatibility will be held in Zurich, Switzerland, on February 13-18, 2005.

4.      The 2005 International Workshop on Seismo Electromagnetics will be held at University of Electro-Communications in Chofu, Tokyo on March 15-17, 2005.

5.      6th International Symposium on Electromagnetic Compatibility and Electromagnetic Ecology will be held in St. Petersburg, Russia, on June 21-24, 2005.

6.      Progress in Electromagnetics Research Symposium (PIERS 2005) will be held in Hangzhou, China, on August 22-26, 2005.

 

 

2. Technical Trends

 

Equivalent Circuit Model for Human ESD

A circuit approach for calculating the discharge current through a hand-held metal piece from a charged human body has been proposed. It has been demonstrated that the currents waveforms can be predicted from the time variant spark resistance and measured frequency characteristics of the human body impedance (Prof. O. Fujiwara). 

 

Application of Meta-Material to EM Wave Absorber and Shielding Material

 Meta-material is the material whose dielectric constant and the magnetic permeability can be controlled. At a special condition, the real part of the dielectric constant and the magnetic permeability are negative. This phenomenon has shown the flexibility to design new typed EM-absorber and shielding material (Prof. S. Kuwabara).

 

Time-Domain Measurement of UWB Radiation Power

 A waveform reconstruction method of the electric field emitted by an ultra wideband (UWB) device has been proposed using the complex antenna factor and oscilloscope. The reconstruction of DSB signal and peak power measurement using a resolution bandwidth of 50 MHz specified in FCC document has been examined. As a result, it has been found that the conversion formula to 50 MHz RBW differs from that of FCC (Dr. S. Ishigami)

 

Simulation of Undesired Noise form Printed Circuit Board

Undesired electromagnetic radiation near PCB with attached feed cable has been investigated by experiment and FDTD simulation. Structure differences of the cross section of tested printed circuit board influences the electromagnetic radiation. Modeling of 3 dimensional FDTD simulation and experiment have been compared in good agreement. It has been reported that the special structure with guard band is able to expect for low common mode current and EM radiation (Prof. H. Inoue).

 

Transmission Characteristics of Micro-strip Line with Large Defected Ground Structure

 The transmission characteristics of micro-strip line with large defected ground structure have been investigated in both the frequency and the time domains. A simple equivalent circuit, which is different from that of a silt model, has been presented to express the characteristics (Prof. Y. Kami) 

 

Multi-Layered Permeable Wave Absorber

A multi-layered permeable wave absorber has been proposed. The basic structure of the absorber is to replace the metal plate in conventional absorber with a resistive film. Its effectiveness has been demonstrated in wireless LAN and ETC (Prof. T. Nakamura).

 

Compact Lightning Wave Recorder

 Malfunctions caused by lightning surges are serious problem for telecommunications equipment used for developed information technology. Lightning surge waveform observation has been carried out to characterize the surges appearing at the telecommunication ports. However, large equipment was needed to observe the waveform. Recent developed semiconductor technology succeeds the miniaturization of waveform recorder. The size of the developed recorder is 94 mm wide, 150 mm long, and 55 mm thick, and the weight is 530 g. The dynamic range is more than 60 dB, and the recording length is 32 ms. Two or more recorders can be operated simultaneously using the external trigger. It is expected to apply the study of the lightning surges inducing mechanism at AC mains and telecommunication port of the equipment (Prof. S. Kuwabara).

 

Lightning and Its Associated Phenomena

The fractal dynamics of intracloud microdischarges responsible for the formation of a so-called drainage system of electric charge transport inside a cloud volume has been discussed. Mesospheric optical emissions (sprites) for the winter lightning were successfully observed in the Hokuriku area, and the associated phenomena (ionospheric perturbations (Trimpis), ELF sferics) were also discussed. The Schumann resonance observation was started again in 1996 at Moshiri, Hokkaido in order to monitor the global warning. The Schumann resonance data there have been used in order to study the correlation of Schumann resonance intensity and ground temperature (Prof. M. Hayakawa).

 

Ionospheric Alfven Resonances

 The results on the basis of 2.5 years observation of ionospheric Alfven resonances at Kamchatka, Russia have been presented. Statistical results have been presented on the spectral resonance structures in the frequency range from 0.1 to 5.0Hz, and a generation mechanism for the ionospheric Alfven resonance at middle latitudes has been suggested (Prof. M. Hayakawa).

 

Electromagnetic Phenomena Associated with Earthquakes

 The presence of ULF electromagnetic emissions before large earthquakes has been noticed by means of different signal analysis methods (including polarization, fractal methods, and principal component analysis etc.). Another important method for short-term earthquake prediction is the use of subionospheric VLF/LF propagation. A case study for the Tokachi-oki earthquake and statistical study on the correlation of the VLF anomaly with different geophysical parameters (geomagnetic activity, particle precipitation) and seismic effect have been performed. The full-wave computation has been made for explaining the shift in the terminator time due to the presence of seismo-ionospheric perturbations (Prof. M. Hayakawa).

 

Seismo-Electromagnetics

The French micro satellite for seismo-electromagnetics "DEMETER" has been launched on June 29, 2004. DEMETER is a project of low altitude microsatellite that mainly aim the study of electromagnetic signals generated by seismic or volcanic events. The data around Japan are registered in the special mode, therefore new findings for physical mechanisms on seismo-electromagnetics are expected in simultaneous measurements on the ground and onboard (Prof. K. Hattori).

 

Precursor of the earthquake

The prediction of earthquake with ELF electromagnetic waves has been developed. New method for detect of precursory phenomena using Schumann resonance on gKiih peninsula earthquakes and on gChuetsuh earthquakes in Niigata is being analyzed (Prof. K. Ohta).