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

TL;DR

This paper introduces two new classes of spherical invisibility cloaks based on nonlinear transformations, segmented into concentric isotropic layers, with detailed analysis of their design, discretization, and performance verified through numerical simulations.

Contribution

It presents novel nonlinear transformation-based spherical cloaks with optimized segmentation for improved invisibility performance.

Findings

Nonlinear transformation cloaks outperform linear ones in certain configurations.

Optimal segmentation significantly enhances cloaking effectiveness.

Numerical simulations confirm improved near-field and far-field invisibility.

Abstract

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).