Multi-layered Radar Absorbing Structure based on Lossy FSS for Broadband Applications

Stealth technology is widely implemented in modern military aircraft in order to reduce radar cross section (RCS) which in turn avoid detection by enemy radars. Multilayered radar absorbing structures (RAS) are used in this respect to get wide absorption bandwidth with minimal thickness. In this regard, a lossy frequency selective surface (FSS) based multi-layered RAS model, having a total thickness of 5.84mm, is proposed in the present paper. The full wave simulation results as well as the equivalent circuit model (ECM) of the proposed design show that the reflection coefficient is below -10dB in the frequency range from 2GHz to 24GHz for wide range of incident angles for both perpendicular as well as parallel polarizations. This in turn implies that the percentage of power absorbed is greater than 90%. Further, RCS analysis of the planar RAS model presents an average RCS reduction (RCSR) of around 12dB.