Material parameters characterization for three-dimensional pyramidal cloak

Arbitrarily three-dimensional (3D) pyramidal cloaks are proposed and designed theoretically based on the coordinate transformation. First, the general expressions of constitutive tensors of the cloaks are derived, and then there are some full-wave simulations which show that the cloak would bend incoming electromagnetic waves and guide them to propagate around inner region. Furthermore, the lossy cases are also considered and simulated. The results validate the constitutive tensors of the 3D pyramidal cloaks, and it is believed that the results are helpful for the practical design and analyze of the 3D cloaks.