On Approximate Electromagnetic Cloaking by Transformation Media

TL;DR

This paper provides a comprehensive analysis of approximate electromagnetic cloaking using transformation optics, addressing passive and active media, cloak-busting inclusions, lossy layers, and frequency effects, supported by numerical demonstrations.

Contribution

It offers a detailed asymptotic analysis of regularized cloaking, including strategies to overcome cloaking failures and insights into frequency-dependent performance.

Findings

Cloaking effectiveness depends on frequency and medium properties.

Lossy layers can mitigate cloak-busting inclusions.

Numerical results confirm analytical predictions.

Abstract

We give a comprehensive study on regularized approximate electromagnetic cloaking via the transformation optics approach. The following aspects are investigated: (i) near-invisibility cloaking of passive media as well as active/radiating sources; (ii) the existence of cloak- busting inclusions without lossy medium lining; (iii) overcoming the cloaking-busts by employing a lossy layer outside the cloaked region; (iv) the frequency dependence of the cloaking performances. We address these issues and connect the obtained asymptotic results to singular ideal cloaking. Numerical verifications and demonstrations are provided to show the sharpness of our analytical study.