arXiv subjects

Baile Zhang

Publications and source records attributed to Baile Zhang.

147 records · Page 9Linked to original sources

arXiv2009

Spherical cloaking using nonlinear transformations for improved segmentation into concentric isotropic coatings

Two novel classes of spherical invisibility cloaks based on nonlinear transformation have been studied. The cloaking characteristics are presented by segmenting the nonlinear transformation based spherical cloak into concentric isotropic homogeneous coatings. Detailed investigations of the optimal discretization (e.g., thickness control of each layer, nonlinear factor, etc.) are presented for both linear and nonlinear spherical cloaks and their effects on invisibility performance are also discussed. The cloaking properties and our choice of optimal segmentation are verified by the numerical simulation of not only near-field electric-field distribution but also the far-field radar cross section (RCS).

physics.optics↗

arXiv2008

A route to quasi-perfect invisibility cylindrical cloaks without extreme values in the parameters

The method of coordinate transformation offers a way to realize perfect cloaks, but provides less ability to characterize the performance of a multilayered cloak in practice. Here, we propose an analytical model to predict the performance of a multilayered cylindrical cloak, based on which, the cloak in practice can be optimized to diminish the intrinsic scatterings caused by discretization and simplification. Extremely low scattering or "quasi-perfect invisibility" can be achieved with only a few layers of anisotropic metamaterials without following the transformation method. Meanwhile, the permittivity and permeability parameters of the layers are relatively small, which is a remarkable advantage of our approach.

physics.optics↗

arXiv2008

Extraordinary surface voltage effect in the invisibility cloak with an active device inside

The electromagnetic field solution for a spherical invisibility cloak with an active device inside is established. Extraordinary electric and magnetic surface voltages are induced at the inner boundary of a spherical cloak, which prevent electromagnetic waves from going out. The phase and handness of polarized waves obliquely incident on such boundaries is kept in the reflected waves. The surface voltages due to an electric dipole inside the concealed region are found equal to the auxiliary scalar potentials at the inner boundary, which consequently gain physical counterparts in this case.

physics.optics↗