Synthesis and microwave absorption enhancement of BaTiO3 nanoparticle/polyvinylbutyral composites

Barium titanate (BaTiO3)-polyvinyl butyral (PVB) composites at various weight concentrations were prepared via ultrasonic probe sonicator. The sonication was carried out at 20？kHz and 70% amplitude for about 2？h and BaTiO3 nanoparticles were dispersed well in the mixture of PVB/ethanol under probe sonication. As a microwave absorbent, the microwave absorbing properties of the BaTiO3 nanoparticle-PVB composites with different mixture ratios of 5？wt.% (RAM1), 10？wt.% (RAM2) and 15？wt.% (RAM3) BaTiO3 were investigated based on transmission line theory in the frequency range from 1 GHz to 14？GHz. The minimum reflection loss (RL) of the RAM1 reaches ？3.47？dB at 5.57？GHz with a matching thickness of only 7.0？mm. For RAM2 with 4？mm and 4.2？mm thickness (tm), the RL values are less than ？10？dB obtained in the frequency 10.3–13.4？GHz. The RAM3 composite with 15？wt.% BaTiO3 mixture ratio shows a minimum reflection loss of ？43.8？dB at 11.01？GHz with a ？15？dB bandwidth over the extended frequency range of 10.2–13.2？GHz for a thickness of 2.8？mm and ？44.2？dB at 4.77？GHz for a thickness of 6.5？mm