# Towards Printable Natural Dielectric Cloaks via Inverse Scattering Techniques

## TL;DR

This paper develops inverse scattering techniques to design printable natural dielectric cloaks, providing analytical and numerical methods to optimize cloaking performance across frequencies and directions.

## Contribution

It introduces new inverse scattering approaches for designing natural dielectric cloaks, including analytical solutions in the quasi-static regime and optimization methods beyond it.

## Key findings

- Analytical solution for homogeneous dielectric cloaks in quasi-static regime.
- Numerical optimization for natural dielectric cloaks beyond quasi-static regime.
- Validated methods with simulations estimating bandwidths and cloaking effectiveness.

## Abstract

The synthesis of non-magnetic 2D dielectric cloaks as proper solutions of an inverse scattering problem is addressed in this paper. Adopting the relevant integral formulation governing the scattering phenomena, analytic and numerical approaches are exploited to provide new insights on how frequency and direction of arrival of the incoming wave may influence the cloaking mechanism in terms of permittivity distribution within the cover region. In quasi-static (subwavelength) regime a solution is analytically derived in terms of homogeneous artificial dielectric cover with $\varepsilon<\varepsilon_0$ which is found to be a necessary and sufficient condition for achieving omnidirectional cloaking. On the other hand, beyond quasi-static regime, the cloaking problem is addressed as an optimization task looking for only natural dielectric coatings with $\varepsilon>\varepsilon_0$ able to hide the object for a given number of directions of the incident field. Simulated results confirm the validity of both analytic and numerical methodologies and allow to estimate effective bandwidths both in terms of frequency range and direction of arrival of the impinging field.