1D-FDTD Modelling of Space-Time Metamaterials using TVTL-based Equivalent Circuit

A methodology for a 1D finite-difference time-domain (FDTD) method based modeling of a space-time mixer circuit using Time-Varying Transmission Lines (TVTLs) is proposed. The lumped time-varying elements in the TVTLs are realized using PIN diodes with alternating current bias. The equivalent circuit of the space-time mixer circuit under forward and reverse bias conditions of PIN diodes is presented and a ID-FDTD simulation model is developed to replicate its behavior to model the space-time mixer circuit. The results obtained from both the FDTD model and the implemented prototype show good agreement.