Title :
Dependence of microwave absorbing property on ferrite volume fraction in MnZn ferrite-rubber composites
Author :
Kim, D.Y. ; Chung, Y.C. ; Kang, T.W. ; Kim, H.C.
Author_Institution :
Korea Res. Inst. of Standards & Sci., Taejon, South Korea
fDate :
3/1/1996 12:00:00 AM
Abstract :
The effective complex permeability and permittivity spectra in composites with various ferrite volume fractions were calculated using the Bruggeman effective medium theory. The matching conditions for the maximum microwave absorption were determined by substituting the complex permeability and permittivity in the equation for the impedance matching condition. The minimum reflection loss increases from -5 to -40 dB as the ferrite volume fraction increases for νf<0.26, where single dip of minimum reflection loss was observed. However, two matching conditions were observed for vf⩾0.26, and two minimum reflection losses shown to be about -40 dB. The results indicate that a microwave absorber with reflection loss of about -40 dB can be designed by controlling the ferrite volume fraction in MnZn ferrite-rubber composites in the frequency range 0.8-12 GHz
Keywords :
composite materials; electromagnetic wave absorption; electromagnetic wave propagation; ferrites; magnetic permeability; manganese compounds; microwave spectra; permittivity; rubber; zinc compounds; -5 to -40 dB; 0.8 to 12 GHz; Bruggeman effective medium theory; MnZn ferrite-rubber composite; MnZnFe2O4; complex permeability spectra; complex permittivity spectra; impedance matching; microwave absorption; reflection loss; Composite materials; Electromagnetic reflection; Ferrites; Frequency; Impedance matching; Magnetic materials; Optical reflection; Permeability; Permittivity; Rubber;
Journal_Title :
Magnetics, IEEE Transactions on
