Towards Printable Natural Dielectric Cloaks via Inverse Scattering Techniques

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 ε < ε 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 ε > ε 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.

Metasurface Design Using Electromagnetic Inversion

“…For example, in [70], it was suggested that we can use electromagnetic inverse scattering algorithms for the design of dielectric profile lenses. Inspired by this work, inverse scattering algorithms have been recently used for the design of cloaking devices and lenses [71,72,73]. Similarly, inverse source algorithms have also been suggested for design applications [74], and have been used, for example, in the design of shaped beam reflectarrays [75].…”

“…In addition to electromagnetic inverse source algorithms, electromagnetic inverse scattering algorithms have also been used for design applications; e.g., see[72].…”

Volumetric Invisibility Cloaks Design Through Spectral Coverage Optimization

“…In particular, it refers to the ratio between the scattering cross-section (SCS) of the covered and bare object. By following [19], for each illumination direction the SCS is defined as:…”

“…Recently, the framework of inverse scattering problems, that is widely applied for diagnosis purposes, has been explored as a powerful synthesis tool for both antennas [14]- [18] and cloaking problems [19], [20].…”

Optimization method in problems of manipulating DC currents

“…Letters [26,27] are devoted to the methods for designing thermal cloaks based on the particle swarm optimization. In [28][29][30][31][32][33][34] the opti-mization method is used for solving the related inverse problems arising in acoustics, electromagnetics and heat conduction. This paper is airmed at theoretical and numerical analysis of the design of functional structures in the form of spherical shells for controlling the steady-state DC electric fields.…”