A new microwave absorber based on antimony-doped tin oxide and ferrite composite with excellent electromagnetic match

Antimony-doped tin oxide (Sn_0.9Sb_0.1O₂, ATO) and W-type barium ferrite (Ba_0.9Gd_0.1(Zn _0.3Co_0.7)₂Fe₁₆O₂₇) were synthesized by coprecipitation method and polymer adsorbent combustion method, respectively. The microstructures were studied using powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the pure ATO with spherical morphology and the pure W-type barium ferrite with hexagonal flake shape were prepared. The complex permittivity and complex permeability of ATO, ferrite and ATO/ferrite composites were analyzed by Agilent 8722ET. It was indicated that ATO had strong dielectric property and ferrite showed superior magnetic performance. An appropriate electromagnetic match was established when the composite microwave absorber contained 50 wt% ATO and 50 wt% ferrite. For the optimized microwave absorber, the maximum reflection loss (RL) was about -19.4 dB at 14.8 GHz. Moreover, the absorption bandwidth reached 3.6 GHz when RL was -10 dB in the measured frequency range of Ku-band.