Metasurface design constraints in metasurface-based virtual absorbers

In this contribution, we will present our investigation on design limits of the metasurfaces to be used for enabling virtual absorbing in metasurface-based virtual absorbers. To reach this goal, we analytically identify the conditions under which a properly modulated monochromatic plane wave can be virtually absorbed by the system, deriving the required metasurface values for a given cavity. The analysis is developed by modelling the system components, i.e., the metasurface reactance and the cavity input impedance, through an equivalent transmission line model, exploring the scattering zeros positions in the complex frequency plane and determining whether the metasurface-based system can support the virtual absorption or not by evaluating the time-constant from its equivalent circuit.