Boosted microwave dissipation performance via integration of magneto/dielectric particles with hierarchical 3D morphology in bilayer absorber

Abstract

In this study, X-band bilayer absorber was designed based on integration of magneto/dielectric phases particles with hierarchical 3D morphology. Pure CoFe2O4, SrFe12O19 and NiO as magnetic and dielectric components with unique 3D morphology were developed via facile chemical method. Morphological evaluations confirmed the formation of hierarchical structure of CoFe2O4 (Co), SrFe12O19 (Sr) and NiO (NiO) with crochet ball, brain-coral and rose-flower-like particles morphology, respectively. In the first step, the synthesized Co and Sr particles were physically blended with 1:1 wt ratio (SC). In a second step, the as-prepared SC composite mixed with NiO powder with 1:1 wt ratio (SCN). The reflection loss simulations of bilayer absorbers with total thickness of 2 mm were performed via CST Studio software based on the electromagnetic characteristics of as-prepared resin base SC and SCN composite monolayer absorbers. The optimized bilayer absorber in which SCN composite placed as matching layer with 1.5 mm thickness and SC composite placed as absorbing layer with 0.5 mm thickness exhibited a minimum reflection loss value of −21.43 dB at 10.8 GHz matching frequency, with 3.2 effective absorption bandwidth and a loading percentage as low as 20 w%. The aforementioned results indicated that tailoring the configuration of particle morphology along with tuning optimal layers thickness could be a rational way to reach considerable absorption bandwidth in double layer absorber. The improvement in microwave dissipation performance is linked to various parameters such as defect induced dipole polarization, multiple scatterings and reflections between particles and pores, coupling interactions between layers, promotion of interfacial polarization, etc.