# A Surface Admittance Equivalence Principle for Non-Radiating and Cloaking Problems

## TL;DR

This paper introduces a surface admittance equivalence principle to control scattering and achieve cloaking in electromagnetic problems, providing analytical solutions applicable beyond subwavelength scales.

## Contribution

It develops a new analytical framework using surface admittance control for non-radiating and cloaking problems, extending previous quasi-static results to general regimes.

## Key findings

- Derived a closed-form scattering control condition.
- Confirmed previous quasi-static results.
- Extended the model to other wave phenomena.

## Abstract

In this paper, we address non-radiating and cloaking problems exploiting the surface equivalence principle, by imposing at any arbitrary boundary the control of the admittance discontinuity between the overall object (with or without cloak) and the background. After a rigorous demonstration, we apply this model to a non-radiating problem, appealing for anapole modes and metamolecules modeling, and to a cloaking problem, appealing for non-Foster metasurface design. A straightforward analytical condition is obtained for controlling the scattering of a dielectric object over a surface boundary of interest. Previous quasi-static results are confirmed and a general closed-form solution beyond the subwavelength regime is provided. In addition, this formulation can be extended to other wave phenomena once the proper admittance function is defined (thermal, acoustics, elastomechanics, etc.).