An Innovative model of magnetically intercalated expanded graphite for calculating radar attenuation performance at 2-18 GHz.

With the emergence of various filtering technologies, the radar jamming efficiency of the technology based on radar cross section is ever lower, therefore cannot meet military requirements. In this context, the jamming technology based on attenuation mechanism has been developed and plays an increasingly important role in disturbing radar detecting. Magnetically expanded graphite (MEG) has excellent attenuation efficiency because it can cause dielectric loss as well as magnetic loss. Moreover, MEG features good impedance matching, which makes more incidence of electromagnetic waves into the material; and its multi-layer structure is conducive for electromagnetic wave reflection and absorption. In this work, the structure model of MEG was established by analyzing the layered structure of expanded graphite (EG) and the dispersion of intercalated magnetic particles. The electromagnetic parameters of thus-modeled MEG were calculated based on the equivalent medium theory; and effects of EG size, magnetic particle type and volume fraction on the attenuation performance were studied by the variational method. It is indicated that MEG with 500-μm diameter has the best attenuation effect and the highest increment of absorption cross section appears at 50% volume fraction of the magnetic particles at 2 GHz. The imaginary part of complex permeability of the magnetic material has the most significant influence on the attenuation effect of MEG. This study provides guidance for the design and application of MEG materials in disturbing radar detecting field.