FDTD Analysis of EM Wave Propagation in a Space-Time-Modulated Lossy Transmission Line

This paper explores electromagnetic (EM) wave propagation in lossy transmission lines (TLs) with space-time-varying parameters, such as capacitance and inductance, using the Finite-Difference Time-Domain (FDTD) method. It examines the effects of spatial, temporal, and spatiotemporal modulation on wave phenomena, including frequency translation, energy dissipation, and non-reciprocal behavior, while accounting for resistive and dielectric losses. A novel perfectly matched layer (PML) formulation, derived from Telegrapher's equations for lossy, space-time-modulated TLs, is proposed to suppress boundary reflections. The results offer key insights into EM behavior in dynamic lossy systems, paving the way for advanced space-time-modulated devices with applications in frequency mixers, isolators, and energy harvesting.