Microwave Absorber Properties of Magnetic and Dielectric Composite Materials

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 epsilon(r)* and permeability In this report, we present the values of the complex permittivity epsilon(r)* and permeability mu(r)* for composite materials including a magnetic component (iron, Fe coated with Fe(3)O(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 mu(r)* = mu(r)' - j mu(r)'') and complex permittivity (epsilon(r)* = epsilon(r)' - j epsilon(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. (C) 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(4): 18-26, 2010; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/ecj.10206