Analysis of impacts of various RAM on RCS of 3-D complex targets using the FEM-FMA

The hybrid vector finite element method and fast multipole algorithm (FEM-FMA) is used to calculate RCS of three dimensional (3D) complex targets coated with various radar absorbing materials (RAM). For a cone as an example, this paper analyzes the impact of four canonical RAM coating including lossy isotropic, positive uniaxial anisotropic, negative uniaxial anisotropic and nanometer absorbing materials on electromagnetic scattering characteristics of the objects. The effect of RCS caused by different coating thickness is discussed and optimal coating thickness is obtained to attain best stealth purpose. Numerical results shows that the back scattering RCS can be reduced about 16.6dB compared with the uncoated objects by using optimal coating RAM. ? 2004 IEEE.EI