Conducting fillers based multilayer polymer composites for terahertz absorber applications

The recent advancement towards THz system design and development, THz spectroscopy and non-destructive testing (NDT) fascinates researchers' attention in the development of absorbing coating and composites to counter stealth technologies and shielding from THz radiation. Conductive fillers based THz absorber composites have emerged as a solution as their properties can be tuned with the change in the filler loading. In this study, several multilayer composites are prepared by wet lay-up process using conducting fillers-chopped carbon fibre (CCF), milled carbon fibre and carbon veil (CV) in epoxy matrix with glass fibre as reinforcement. These composite samples were evaluated for absorption in 0.1-2.5 THz frequency domain to explore their use for THz absorber applications. The results show that the absorption performance of fabricated composite structures is significantly affected by the type of filler, percentage loading of filler and frequency range. The polymer composite with CV filler exhibits maximum 99% absorption (10-20 dB reflection loss) in the frequency range of 0.5-2.25 THz. Considering the high mechanical strength and broadband absorption of THz radiations, these composites may provide a better substitute for fragile wideband THz absorptive coatings as well as metamaterials based narrowband THz absorbers.