Optimization of loss and gain multilayers for reducing the scattering of a perfect conducting cylinder

Yu Zhen-Zhong^†,, Zhao Guo-Shu, Sun Gang, Si Hai-Fei, Yang Zhong

In the low-loss (a) and high-loss (b) cases, the normalized total scattering cross section as a function of normalized frequency for the uncloaked PEC cylinder with radius a = 2λ/3 (solid), for the optimized five-layer low-loss cloak with gain material (dashed), and for the optimized cloak without gain (circle dot).