Analysis of impacts of various RAM on RCS of 3-D complex targets using the FEM-FMA [radar absorbing materials]

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