Title :
Control of complex permeability and permittivity by air cavity in ferrite-rubber composite sheets and their wide-band absorbing characteristics
Author :
Park, Myung-Joon ; Kim, Sung-Soo
Author_Institution :
Dept. of Mater. Eng., Chung-Buk Nat. Univ., Cheongju, South Korea
fDate :
9/1/1999 12:00:00 AM
Abstract :
Wide-band absorbing characteristics in the GHz-range are identified in the ferrite-rubber composite sheets with the periodic structure of an air cavity. Co2Z and Ni-Zn ferrites, which have been prepared by ceramic processing, are used as the absorbent fillers. On the basis of a synthesized capacitance and inductance model, the equivalent permeability (μeq) and permittivity (εeq) are calculated as a function of the volume of air cavity (K). Reduction in the material parameters (especially, permittivity and magnetic loss) has been estimated with the increase of K. By plotting the μeq and εeq on the solution map of wave-impedance-matching, wide-band microwave absorbance has been estimated in both Co2Z and Ni-Zn ferrite composites with an optimum value of K
Keywords :
composite materials; electromagnetic wave absorption; ferrites; magnetic permeability; microwave materials; periodic structures; permittivity; rubber; Ba3Co2Fe24O41; Co2Z ferrite; GHz-range; Ni-Zn ferrite; NiZnFe2O4; absorbent fillers; air cavity; capacitance/inductance model; ceramic processing; complex permeability control; complex permittivity control; equivalent permeability; equivalent permittivity; ferrite-rubber composite sheets; magnetic loss; periodic structure; wave-impedance-matching; wideband absorbing characteristics; wideband microwave absorbance; Capacitance; Ceramics; Composite materials; Ferrites; Inductance; Magnetic materials; Periodic structures; Permeability; Permittivity; Wideband;
Journal_Title :
Magnetics, IEEE Transactions on
