Electromagnetic interaction of arbitrary radial-dependent anisotropic spheres and improved invisibility for nonlinear-transformation-based cloaks

TL;DR

This paper develops an analytical method to analyze electromagnetic interactions with radially anisotropic spheres and designs nonlinear cloaks with enhanced invisibility using metamaterials.

Contribution

It introduces a general analytical approach for radially anisotropic cloaks and proposes a new class of nonlinear spherical cloaks with improved invisibility performance.

Findings

Established a method for arbitrary anisotropic parameters

Derived parameters for nonlinear cloaks

Achieved improved invisibility with optimal design

Abstract

An analytical method of electromagnetic wave interactions with a general radially anisotropic cloak is established. It is able to deal with arbitrary parameters ($\epsilon_r(r)$, $\mu_r(r)$, $\epsilon_t(r)$ and $\mu_t(r)$) of a radially anisotropic inhomogeneous shell. The general cloaking condition is proposed from the wave relations for the first time. We derive the parameters of a novel class of spherical nonlinear cloaks and examine its invisibility performance by the proposed method at various nonlinear situations. Spherical metamaterial cloaks with improved invisibility performance is achieved with optimal nonlinearity in transformation and core-shell ratio.