Enhanced microwave magnetic and attenuation properties of composites with free-standing spinel ferrite thick films as fillers

Abstract

Free-standing thick films of spinel ferrite, Ni 0.89-xCu 0.11Zn xFe 2O 4 with x=0.55 and 0.60, were prepared as fillers to fabricate electromagnetic composites. Compared to those made with conventional spherical fillers, the composites made with thick film fillers showed enhanced static permeability (μ′ 0) and maximum imaginary permeability (μ″ max). At the same time, complex permittivity (ε′ and ε″) were almost unchanged. A relative bandwidth W R of 7-8 was achieved, which is about 75% of the theoretical maximum relative bandwidth. These composites are potential candidates as electromagnetic attenuation materials with ultrabroad absorption bandwidth in L and S bands. © 2012 Elsevier B.V. All rights reserved.