FDTD Analysis of Space-time Metamaterials using Modulated TVTLs for Frequency Translation, Mixing and Non-reciprocity

This paper presents a comparative analysis of the variation of relative permittivity of a dielectric slab and capacitance per unit length of a transmission line (TL) section undergoing spatial, temporal, and spatio-temporal modulation. The relationship between translated and source frequency for the time-varying transmission line (TVTL) is established. Frequency mixing using a time-varying TL section and non-reciprocity in a space-time-varying TL section are demonstrated. Insights into the attenuation of source frequency in a forward propagating wave are provided via parametric study for magnet-less isolator applications.