Summary of Research Project Results under JSPS FY2003
"Research for the Future Program"

1.Research Institution Okayama University
2.Research Area Physical and Engineering Sciences
3.Research Field Reduction of Electromagnetic Noise Levels
4.Term of Project FY 1999 - FY 2003
5.Project Number 99P01504
6.Title of Project Control of Unintentional Electromagnetic Waves from Digital Circuits

7.Project Leader
Name Institution,Department Title of Position
Ryuji,Koga Okayama University, The Graduate School of Natural Science and Technology Professor

8.Core Members

Names Institution,Department Title of Position
Osami,Wada Okayama University, The Graduate School of Natural Science and Technology Associate Professor

9.Summary of Research Results

   The subject of this project is to develop effective methods to control electromagnetic (EM) noise radiation from digital electronic devices and circuits conforming electromagnetic compatibility (EMC). Engineering approaches were chosen and some new modeling methods of electromagnetic phenomena around a printed circuit board (PCB) and digital devices were developed for electro- magnetic interference (EMI) control. Those results have been combined into EMI simulator software, HISES, which works very rapidly still retaining enough accuracy in EMC issues.
1) An EMC macro model of IC/LSI was proposed and developed for modeling of core circuits and I/O circuits. Accuracy and effectiveness of the model proposed in this project, called LECCS (linear equivalent circuits and current source) model, were confirmed through measurement and simulation. Standardization of EMC models of semiconductor devices is now under discussion, and the LECCS model and the ICEM model, which is under development in European research project, are the most promising candidates of an international standard.
2) High-speed analysis method of power and ground planes of PCB was developed. A multi-layer PCB, that has a stacked two-dimensional structure, allows a simplification of Green's functions that express electromagnetic modes in it, especially in power-bus systems. A new technique to analyze EM field distribution is far faster, about 400 times, than conventional method, and was implemented as a software HISES equipped with a versatile interface.
3) Imbalance difference theory was proposed and applied to several structures of PCBs efficiently to evaluate the common mode generation which is one of the major sources of EMI. The new evaluation scheme explains that even a narrow ground plane can sustain low EMI, which creates a new transmission system with more flexible structure still retaining low radiated emission.

10.Key Words
(1)digital circuit   (2)electromagnetic interference (EMI)   (3)EMC macro model
(4)LECCS model   (5)printed circuit board (PCB)   (6)power-bus
(7)imbalance difference   (8)common mode   (9)EMI simulation