Microwave Behaviour Of Substitute Lithium Ferrite Composites In X-Band

摘要

Dense and crack-free substituted lithium ferrite-polymer composite films of thickness - 80 μm were fabricated by citrate-route method. The substituted lithium ferrites with general composition Li_(0.5-x/2)Co_xMn_(0.1)Fe_(2.4-x/2)O_4, where x = 0.0,0.2,0.4 and 0.6, were prepared. Epoxy resin EPG-280 was used as a polymer. These composite films required lower processing temperature ～ 100℃. Cavity-perturbation technique was employed to measure the complex permittivity and the complex permeability of the composite films at X-band microwave frequencies (8-12 GHz). The dispersion in the complex permittivity (ε′-j ε″) of ferrite composite films was found to be significant The maximum value of ε″ was observed for x = 0.6 and 50/50 ferrite-epoxy ratio. The permeability μ′ of films was found to decrease with increase in frequency. The single-phase spinel structure of composite films was confirmed by X-ray diffraction pattern (XRD) and their microstructure was observed by scanning electron microscopy (SEM).