1996 Fiscal Year Final Research Report Summary
Study of super broad-band electromagnetic wave absorber with thin structure
| Project/Area Number |
06555101
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (A)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 試験 |
|---|
| Research Field |
電子デバイス・機器工学
|
|---|
| Research Institution | Tokyo Institute of Technology |
|---|
Principal Investigator |
NAITO Yoshiyuki Tokyo Institute of Technology, Department of Physical Electronics, Professor, 工学部, 教授 (70016335)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
YOKOI Hideki Tokyo Institute of Technology, Department of Physical Electronics, Research Asso, 工学部, 助手 (90251636)
ANZAI Hiroki Tokyo Institute of Technology, Department of Physical Electronics, Research Asso, 工学部, 助手 (80212661)
MIZUMOTO Tetsuya Tokyo Institute of Technology, Department of Physical Electronics, Associate Pro, 工学部, 助教授 (00174045)
|
|---|
| Project Period (FY) |
1994 – 1996
|
| Keywords | noise emission / electromagnetic wave absorber / anechoic chamber / return loss / ferrite / rubber ferrite / site attenuation |
|---|
| Research Abstract |
Electromagnetic wave absorbers lined in anechoic chambers are investigated. The purposes of this study are to broaden a bandwidth of N-type absorber which provides return loss > 20dB at frequencies higher than 30MHz, to make a thin W-type absorber which provides return loss > 20dB at any frequency higher than 30MHz, and to exploit the site attenuation characteristic of anechoic chamber lined with the absorber for designing the chamber with desired characteristics. The results obtained are summarized in the following.
1. A novel broad-band N-type absorber which exhibits return loss > 20dB in the ferquency range of 30MHz-1700MHz is developed. The absorber is constructed with a ferrite grid and a rubber ferrite plate. Also, it is found that the degradation of return loss characteristics brought about by gaps between absorber units is much less in the ferrits grid absorber compared with others.
2. W-type absorbers of 500mm thickness are realized by attaching lossy dielectric to broad-band N-type absorbers. Sufficient return loss characteristics are successfully demonstrated. Its thickness is less than a half compared with conventional absorbers. Also, the analytical technique which gives accurate results even for angled incidence is developed to calculate return loss characteristics of pyramidal absorbers.
3. Numerical calculation based on a ray-tracing technique is developed to exploit the site attenuation characteristics. It reveals the required return loss of absorber to construct anechoic chambers with desired site attenuation characteristic.
|
