On the Use of Nonlinear Metasurfaces for Circumventing Fundamental Limits of Mantle Cloaking for Antennas

TL;DR

This paper explores how nonlinear metasurfaces can overcome fundamental limits of mantle cloaking for antennas, enabling dynamic invisibility and radiation pattern shaping based on power levels, thus offering new functionalities for radiating systems.

Contribution

It introduces nonlinear metasurfaces that adaptively modify cloaking properties depending on incident power, surpassing traditional static cloaking limits for antennas.

Findings

Nonlinear metasurfaces enable dynamic cloaking at different power levels.

The proposed design allows high-power transmission while maintaining invisibility at low power.

Power-dependent radiation pattern shaping is achievable with nonlinear cloaks.

Abstract

The aim of this communication is to investigate and demonstrate the possibility to overcome the fundamental limitations of mantle cloaking for antennas by exploiting nonlinear metasurfaces. First, we recap and give additional physical insights about the fundamental bounds that apply to the electric properties of an antenna that is made invisible at its own resonance frequency. Then, an innovative strategy is proposed to circumvent these limits through the introduction of nonlinear elements that are able to dynamically transform the geometry of the cloaking metasurface depending on the power level of the impinging field. Different nonlinear designs are discussed, and their effectiveness is assessed through the relevant benchmark example of a half-wavelength dipole antenna able to efficiently transmit high-power signals while being invisible to low-power ones. In addition, the capability of such nonlinear mantle cloaks to enable the shaping of the radiation pattern of an antenna array depending on the power level of the received/transmitted signal is demonstrated. These innovative cloaking devices may find applications in different radiating systems enabling unprecedented functionalities.