Development of CI/BFO nanocomposite for efficient microwave absorption in low frequency range of L, S, C, and X – bands

The electronic industry's rapid progress demands highly efficient microwave absorbers with low coating thickness, broad bandwidth, and simple manufacturing. However, achieving all these properties together remains challenging, especially for low-frequency ranges. In this study, a carbonyl iron/barium hexaferrite (CI/BFO) nanocomposite was prepared via facile high-energy ball milling technique, resulting in excellent microwave absorption in L, S, C, and X-bands. The modified morphology of the CI/BFO nanocomposite significantly enhanced the microwave absorption bandwidth. For a 15 h milled sample with 10 wt% of BFO nanoparticles, an effective broad bandwidth (RL < − 10 dB) of 9.15 GHz in 1.9 – 11.05 GHz frequency range was obtained with a low coating thickness of 2.5 mm. An advanced electromagnetic technique utilizing Genetic Algorithm (GA) for designing triple-layer microwave absorbers was employed to improve absorption bandwidth further and decrease layer coating thickness. The optimized design of triple-layer microwave absorber showed an impressive effective bandwidth of 15.12 GHz, covering 2.88 – 18 GHz frequency range while maintaining an overall coating thickness of only 1.77 mm. The developed CI/BFO nanocomposite showcased remarkable ability to absorb microwaves across a wide frequency range due to various absorption mechanisms like eddy currents, conduction, electron hopping, and multiple interfacial polarization, making it highly suitable for ultra-broadband microwave absorption in practical applications.