Electromagnetic radiation suppressor based on Co-Ti doped strontium lanthanum hexaferrite for Ku-Band applications

Abstract

In this proposed work, we report Co-Ti doped Strontium-lanthanum M−type hexaferrites with general chemical formula, Sr0.85La0.15(CoTi)0.5Fe11O19 and Sr0.85La0.15(CoTi)0.75Fe10.5O19 prepared by citrate auto-combustion method. Complex permittivity, complex permeability and microwave absorptive properties of fabricated ferrite compositions were analysed in 12.4 to 18 GHz frequency range (Ku-Band). The XRD (X-ray diffraction) pattern of Co-Ti substituted compositions show single-phase M−type hexagonal ferrite indicating this co-substitution maintained the crystal phase structure. The grain diameter (average) decreased from 587 nm to 290 nm and 415 nm to 318 nm for ferrite samples with composition x = 0.50 and x = 0.75 respectively after 20 hours of ball-milling. The reflection loss (RL) exhibited the absorption bandwidth of more than 90 % (−10 dB) of value 2.41 GHz and 1.2 GHz for fabricated ferrites with chemical composition Sr0.85La0.15(CoTi)0.5Fe11O19 and Sr0.85La0.15(CoTi)0.75Fe10.5O19 respectively.. Both dielectric loss tangent and magnetic loss tangent contributed to enhance total loss tangent which represents microwave absorbing properties of the prepared ferrite samples. Reflection coefficient (S11) values for open circuit method also shows absorption bandwidth (−10 dB) of more than 90 % for these ferrites. Double layer electromagnetic absorber was simulated and observed improved reflection loss and absorption bandwidth. Therefore, these suggested ferrite samples have potential to be used as electromagnetic wave absorbing material of both single and double layer at higher frequency range.