Broad microwave absorption bandwidth analysis of biocomposite microwave absorber material for X-band applications

In this research paper, biocomposite microwave absorber materials (MAMs) was fabricated, tested, and analyzed. The biocomposite MAMs have been prepared of pure dried banana leaves (DBL) and multi-walled carbon nanotubes (MWCNTs). The developed composite MAMs are environment friendly and cost-effective with broad absorption bandwidth, minimum thickness, and lightweight material. The DBL and their composites with MWCNTs consisting of different concentrations of 1, 3, and 5 wt% were fabricated and analyzed for their microwave absorption capabilities at 4 mm and 2 mm thickness for frequency range 8.2 to 12.4 GHz (X-band). The results showed that DBL-MWCNT composite with 5 wt% of MWCNTs significantly improved microwave absorption properties, achieving wide (effective absorption bandwidth) EAB (RL <  − 10 dB) of 3.7 GHz, covering 88.09% of the X-band, with a minimum reflection loss (RL) of − 50.8 dB at a thickness of 4 mm. In contrast, DBL sample exhibited a narrower EAB of 0.7 GHz for X-band. To address this limitation, further, thinner samples with a 2 mm thickness were prepared. It was found that DBL-MWCNT composite with 5 wt% of MWCNTs with 2 mm thickness demonstrated an effective absorption bandwidth (RL <  − 10 dB) of − 2.5 GHz, covering 60% of X-band frequencies, with a RL of − 42.9 dB, while DBL sample showed an RL − 11.53 dB. The adding of different wt% of MWCNTs into pure DBL significantly enhanced the dielectric properties with wide effective absorption bandwidth, which made proposed biocomposite MAMs suitable for different application like satellite communications, military operations, aerospace, and radar systems.