Influence of Sb content on electromagnetic properties of ATO/ferrite composites synthesized by co-precipitation method

Composite microwave absorbers based on ATO (antimony-doped tin oxide) and W-type ferrite were prepared by a co-precipitation method, and the effects of Sb content on electromagnetic properties and reflection loss characteristics were studied in 2-18 GHz. The prepared composite particles were characterized with X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). The results showed that the nano-particles ATO were coated with the surface of hexagonal flake ferrite, and with the increase of Sb content, the grain size of ATO nano-particles decreases resulting in agglomeration. The complex permittivity and permeability of the ferrite/ATO composites were analyzed by a vector network analyzer (Agilent E5071C), and the reflection loss was simulated by software YRComputer. The dielectric loss mainly comes from ATO, with the increase of Sb content, the real and imaginary parts of permittivity of the composites increase first, then decrease; The interface effects and surface effects lead to the increase of imaginary part μ" of the absorbing materials in the macro; When the mole ratio of Sb/Sn is 2:10, the reflection loss reaches the maximum value -43.07 dB at 10.64 GHz for a layer 2.8 mm, and the bandwidth over an absorptivity of 90% (-10 dB reflection loss) is 8.32 GHz (ranging from 7.12 GHz to 15.44 GHz).