Enhanced microwave absorption properties of Ni-Zr doped La-Sr hexagonal ferrites in 18?40 GHz frequency range

In this research, electro-magnetic (EM) absorption properties for M-type hexaferrite with chemical composition, Sr0.85La0.15(NiZr)xFe12-2xO19 (x = 0.00, 0.25, 0.50, 0.75, 1.00) are investigated at microwave frequencies. Complex permittivity and complex permeability were determined using vector-network analyser (VNA) in Kband (18?26.5 GHz) and Ka-band (26.5?40 GHz) frequency range. Quarter-wavelength mechanism was successfully implemented to optimize the electro-magnetic reflection loss in the material. The reflection loss (RL) of different compositions has been studied as a function of frequency, sample thickness and substitution. Minimum reflection loss (RL) of -21.74 dB was obtained for composition x = 0.50 with -10 dB (90%) bandwidth of 10.53 GHz for a sample thickness of 0.96 mm. These newly synthesized ferrites have high potential as compact microwave absorbing material with broad-bandwidth for anti-radar signatures and electromagnetic interference absorbers.