Shape optimizations of metallic sheets for improved near-zone scattering, reflection, and focusing characteristics

We consider full-wave analysis and optimizations of metallic sheets to obtain desired electromagnetic responses in the near-zone field intensity and power density distributions. Given a metallic sheet of finite size, deformations are applied to achieve diverse scattering and reflection characteristics, particularly focusing and collecting electromagnetic power at different locations. Optimizations are performed by employing genetic algorithms in a multigrid scheme on the discretized geometry, while each trial is considered as a full-wave electromagnetic problem to be solved by the multilevel fast multipole algorithm. Numerical results demonstrate the effectiveness of the optimizations, which can lead to different reflection characteristics even for relatively small-scale metallic patches.