Novel radar absorbing material using resistive frequency selective surface based polymer composites for enhanced broadband microwave absorption

In this paper, a novel approach using glass fibre laminate composite (GFLC) with nanoparticle embedded nanofibres and frequency selective surfaces (FSS) for improved electromagnetic (EM) wave absorption has been proposed. For enhanced absorption, the FSS was coated with polyvinylidene fluoride (PVDF) mixed with multi-walled carbon nanotubes (MWCNTs). The coatings were prepared through electrospinning technique. The composite prepared from FSS, PVDF-MWCNT layers and GFLC showed enhanced absorption properties. It was demonstrated that the fabricated composites reduced reflection of electromagnetic waves by the material when compared to metals. An 80% increase in EM absorption (with respect to metal) was observed over a wide frequency range with the novel composite at an overall thickness of only 3 mm. X-ray diffraction (XRD) spectra showed an improvement in the electroactive beta-phases in the electrospun PVDF/MWCNTs compared to Plain PVDF. Scanning electron microscopy analysis on various weight percentages of PVDF/MWCNTs revealed the formation of nano fibres with an average diameter of 75-160 nm. In addition, the proposed novel EM wave absorbing composites were of simple configuration and the mechanical properties of the fabricated composites were comparable to that of GFLC. Experimental results indicated that RAS with 0.25 wt % MWCNT/PVDF had 87.5% bandwidth for over 90% absorption from 8.5 to 12 GHz compared to all other configurations. The tailored composite material could be used as excellent radar absorber structures (RAS) and can find tremendous application in the manufacture of stealth aircrafts.