Investigation of Electromagnetic Properties of La-Doped Strontium Ferrite in X and Ku Bands

Abstract

In the present study, the lanthanumsubstituted strontium ferrite particles with general formula, Sr1−xLa x Fe12O19 (x = 0, 0.10, 0.15, 0.20, and 0.25) were prepared using citrate auto-combustion method. These ferrites were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), vibrating sample magnetometer (VSM), and vector network analyzer (VNA). X-ray diffraction patterns show the formation of M-type hexaferrite phase without any secondary phases for all the synthesized samples. The complex permittivity (e ′– j e ″) and complex permeability (μ ′–j μ ″) were measured using VNA in X-band (8.2–12.4 GHz) and Ku-band (12.4–18 GHz) frequency range at room temperature. More than 90 % absorption was obtained in the Ku band for all the La3+ substituted strontium ferrites. The composition x = 0.15 exhibits a minimum reflection loss of −20.66 dB at 16.5 GHz and an absorption bandwidth of 2.1 GHz (15.63 to 17.64 GHz) with an absorber layer thickness of 1.6 mm. These materials can be used as cost-effective and thinlayer microwave absorbers in higherfrequency range.