Utilization of soft magnetic nanoparticles for ultra-high frequency range

Abstract

In the communication sector especially at ultra-high frequency range, a major challenge is to maintain the real permeability (μ′) and real permittivity (ε′) with controlled electromagnetic losses. To fulfill this demand, the present work reported electromagnetic studies over the frequency range of 2–3.4 GHz for magnetic nanoparticles of Sr2+-doped Z-type hexaferrites of compositions Ba3-xSrxCo2Fe24O41(x = 0, 0.5, 1.0, 1.5 and 2.0) synthesized by sol-gel auto combustion soft chemical route. The most desirable results obtained at 2 GHz for composition Ba1·5Sr1·5Co2Fe24O41 hexaferrite were μ′ = 5.002 with magnetic loss tangent of 0.003, and ε′ = 4.734 with electric loss tangent of 0.005. The multiple manifestations of electromagnetic studies are reported which are explained on the basis of a suitable Globus model, a theoretical model of Herzer, Snoek's law, a Maxwell–Wagner model together with Koop's model, and pertinent existing theories. Such magneto-dielectric substrate material could be favorable for fabrication of antennas with reduced physical dimensions and, also, almost equal values of μ′ and ε′ led to good impedance-match to free space in the gigahertz range for communication applications.