A Simulation Technique for Radiation Properties of Time-Varying Media Based on Frequency-Domain Solvers

A novel simulation technique is proposed for the radiation properties of time-varying media. This method divides the time-variation process into finite discrete time steps. The radiation field of the media at each instant in time is simulated by using commercially available frequency-domain solvers, and then these results are processed and synthesized to obtain the radiation field of the time-varying media. In other words, by using this technique, the radiation field of the time-varying media can be obtained based on the frequency-domain simulation results. The proposed technique is introduced with a time-varying grating, and the scattered wave and radiation pattern are illustrated. Moreover, an analytical model of the time-varying grating is also introduced to further explore the proposed technique. This simulation technique can be used to analyze many applications such as the radiation properties of time-modulated media, especially space-time-modulated metamaterials. It fills the gap of existing simulation methods and provides a new way for direct EM simulation of time-varying structures.