Permittivity Adjustment and Impedance Matching of Ferrite Composite Microwave Absorber

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J. Korean Ceram. Soc. > Volume 29(4); 1992 > Article

Journal of the Korean Ceramic Society 1992;29(4): 293.

복합 Ferrite 전파흡수체의 유전율 제어 및 임피던스 정합

최경구, 조성백, 권경일, 김성수, 김재묵

국방과학연구소

Permittivity Adjustment and Impedance Matching of Ferrite Composite Microwave Absorber

ABSTRACT

A proper combination of complex permeability and permittivity is necessary to produce the zero-reflection microwave absorber with an impedance matching. Increasing of dielectric permittivity and development of an impedance matching was investigated in ferrite-rubber composite specimens by addition of conducting materials. Graphite powder of high dielectric constant was added to the composite specimens to increase the permittivity. The precise estimation of graphite content to produce the matched-wave-impedance absorber at a given frequency can be made by using the numerically derived solution map of impedance matching. It was suggested that permittivity adjustment is an effective technique to obtained the microwave absorber with both good absorbing properties and small thickness as well.