Event-Driven Electromagnetic Shielding Using Time-Varying Thin Layers

This paper studies the time-domain interaction between a normally incident plane wave and a thin electromagnetic layer with time-varying material properties. Under the electrically thin assumption, the one-dimensional TEM Maxwell equations are mapped onto a symmetric T-network whose lumped elements are directly linked to the layer parameters, including the additional terms induced by temporal modulation. The formulation admits a compact state-space representation from which reflected and transmitted fields are directly obtained. The approach is applied to a burst-selective shielding strategy based on gated conductivity, where σ(t) is increased only during high-energy intervals. A 1-D FDTD solver and matched PML is used for validation, and results are compared with a time invariant baseline defined by the averaged material parameters. Numerical results show that temporally concentrated dissipation significantly reduces transmitted field peaks, instantaneous power flux, and total transmitted energy per unit area, despite identical average conductivity. These results demonstrate the effectiveness of event-driven time-varying conductive layers for adaptive electromagnetic shielding under nonstationary excitations.