Tayca Corporation Osaka Research Laboratory

Ōsaka, Japan

Tayca Corporation Osaka Research Laboratory

Ōsaka, Japan
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An Y.J.,Japan National Defense Academy | Nishida K.,Japan National Defense Academy | Yamamoto T.,Japan National Defense Academy | Ueda S.,Tayca Corporation Osaka Research Laboratory | Deguchi T.,Tayca Corporation Osaka Research Laboratory
Electronics and Communications in Japan | Year: 2010

In recent years, because of rapid progress in wireless technology, microwave absorbers or noise suppressors have become necessary for an environment with safe electromagnetic wave levels. To design microwave absorbers or noise suppressors, it is necessary to have a knowledge of the complex permittivity ε * r and permeability μ *. r In this report, we present the values of the complex permittivity ε * r and permeability με * rfor composite materials including a magnetic component (iron, Fe coated with Fe 3O 4) and a dielectric component (titanium oxide, TiO 2) obtained by varying the Fe/TiO 2 volume fraction ratio. By varying this ratio, we can change the values of the complex permeability μ *-r μ *-r'jμ *-r") and complex permittivity (ε * r = ε * r'-jε * r"). The results are applied to the design of a microwave absorber in order to tailor the reflection loss and the central frequency to particular requirements, for example, the conditions required for ETC (5.8 GHz) use in Japan. ©2010 Wiley Periodicals, Inc.


An Y.J.,Japan National Defense Academy | Soonpan P.,Japan National Defense Academy | Nishida K.,Japan National Defense Academy | Yamamoto T.,Japan National Defense Academy | And 2 more authors.
Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy | Year: 2011

In general, there are two types as practical microwave absorbers; resonant or graded dielectric. Especially the resonant absorber is used as the simplest type of absorber which consists of a resistive sheet spaced one-quarter wavelength from a conductive ground plane. In this study, we propose the new type of resonant absorber which consists of magnetic (Fe) and dielectric (TiO 2) composite material, metal pattern sheet, no loss dielectric material and metallic plate at the back. The composite microwave absorber with metal pattern sheet was applied in the design of a microwave absorber for high frequency region. The central frequency of absorption and the reflection loss could be controlled by changing the size and interval of metal pattern. By optimizing composition of absorbing layer and geometry of metal pattern, thinner and lighter composite microwave absorber with metal pattern satisfied the necessary conditions of central frequency 5.8 GHz and reflectivity - 20 dB or more around for ETC use in Japan.

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