Microwave absorption properties of hollow microsphere/titania/M-type Ba ferrite nanocomposites

Abstract

Low density composite powders of hollow microsphere/titania/$M$ -type Ba ferrite were prepared using a two-step sol-gel technique. Their electromagnetic wave absorption properties were investigated in the $2–18\mathrm{GHz}$ frequency range. Reflection loss less than $-20\mathrm{dB}$ was obtained between $7.5–9.4\mathrm{GHz}$ for paraffin composites containing $25\mathrm{wt}\%$ titania over an absorber thickness of $2.0–3.0\mathrm{mm}$ . A minimum reflection loss of $-30.1\mathrm{dB}$ was observed at $8.5\mathrm{GHz}$ with a thickness of $2.4\mathrm{mm}$ . The strong electromagnetic absorption properties are due to the introduction of a titania intermediate layer.