Improving performance of mantle cloak for electrically large PEC cylinders by reducing higher-order scattering coefficients

Based on the scattering cancellation technique, an approach is proposed to improve the mantle cloak’s performance for electrically large cylinders. The procedure is based on the observation that the number of dominant scattering coefficients and corresponding magnitudes for a cylinder decreases when oriented obliquely to the incident wave. Thus, it is quite advantageous to design a mantle cloak under the oblique incidence than the normal incidence. The proposed method starts with determining the optimum angle of incidence at which if the object is oriented with respect to the incident wave, the maximum scattering reduction can be obtained with a mantle cloak explicitly designed for that orientation. The procedure is applied to cylinders of radii $ 0.25\lambda _0 $ 0.25λ0 and $ 0.85\lambda _0 $ 0.85λ0, where $ \lambda _0 $ λ0 is the design wavelength. The proposed approach’s advantages are highlighted by comparing it with the previously published literature. Additionally, the mantle cloak is realized using a periodic grid of metallic patches, and simulations in Ansys HFSS are performed to verify the design.