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

1.Research Institution The University of Electro-Communications
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 99P01502
6.Title of Project Studies on Measurement of Unintentional Electromagnetic Waves and Estimation of their Influences

7.Project Leader
Name Institution,Department Title of Position
Yoshio,Kami The University of Electro-Communications, Faculty of Electro-Communications Professor

8.Core Members

Names Institution,Department Title of Position
Takashi,Iwasaki The University of Electro-Communications, Faculty of Electro-Communications Professor

9.Summary of Research Results

   In this research project, two study programs, "Measurement of unintentional electromagnetic waves" and "Measurement and estimation method for radiated immunity", were performed.
   In the first program, complex antenna factor (CAF) was proposed as a new measure of detecting antennas for measuring transient or pulse electromagnetic fields. A modified three-antenna method introducing a field transfer factor (FTF) and a measured balun method have been developed for determining the CAF. It is made sure that the complex antenna factors of a dipole antenna, log-periodic dipole array antenna, monopole antenna, and loop antenna can be determined by the two methods. An inverse filtering technique for reconstructing electromagnetic waveforms using the CAF was proposed. The technique was confirmed by comparing the reconstructed waveforms with the waveforms calculated from radiating antennas. In addition, a method for estimating the direction of arrival (DOA) of a pulse electromagnetic wave has been developed. The developed method can estimate the DOA with a high angular resolution.
   In the second program, a novel immunity/susceptibility test method using electromagnetic fields rotating slowly in a two-dimensional plane was proposed. The method enables the electromagnetic waves scan allover the surface of equipment under test (EUT) by using a turntable. The evaluation map of the immunity/susceptibility of EUT can be depicted in a three-dimensional visual view in a short time, so that weak/strong points in terms of direction and polarization of the applied electromagnetic waves can be known instantly. Such results are applied to a product-design cycle. By applying the method, a new four-septum TEM cell is also proposed to estimate the characteristics of EUT of small size by rotating TEM fields. To study the mechanism of susceptibility phenomenon, coupling of the transient near fields to transmission lines was studied comparing the experimental and the numerical results to check the validity of telegrapher's equations in time domain.

10.Key Words
(1)Complex antenna factor  (2)Site S parameter   (3)Transient EM fields
(4)Waveform measurement  (5)Radiated immunity   (6)Susceptibility
(7)Slowly rotating polarization  (8)Four-septum TEM cell   (9)Poynting vector