Microwave scattering parameters of ferro–nanocarbon composites for tracking range countermeasures

Abstract

In the strategic sector, frequently, the radar signatures in the microwave frequency region are cluttered, which can be overcome by designing and developing an effective electromagnetic interference (EMI) shield. Herein, we report the analysis of the s-parameter performance of ferro–nanocarbon (FNC) composites tested over the frequency region of 8–12 GHz (X-band). The FNC composite was prepared via a simple, single-pot, solid-state sublimation route with different contents of iron (1–4%). The fabricated material was characterised using X-ray diffractometry, scanning electron microscopy, vibrating sample magnetometry and several spectroscopic techniques such as infrared, UV-visible, and energy dispersive X-ray analysis. S-parameter and reflection loss studies were performed by transforming the composite material into a coaxial- and rectangular-shaped specimen, respectively. In the analysis, the inclusion of iron resulted in the formation of crystalline Fe₂O₃ (d[110]) and Fe₃O₄ (d[220]) phases, which were self-dispersed in the nanocarbon structure. The inclusion of iron was responsible for creating an asymmetric bond molecular environment in C–O–Fe, resulting in synergistic magneto-dielectric effects in terms of long-range polarization ordering mainly through the transitions between the O-2p and Fe-3d states to engage the incoming microwave field effectively. This composite showed a good performance of >98% shielding effectiveness with an infinite bandwidth and >99% return loss at a matching frequency of 9.01 GHz.