RESUMEN
Electromagnetic scattering in moving structures is a fundamental topic in physics and engineering. Yet no general numerical solution to related problems has been reported to date. We introduce here a generalized FDTD scheme to remedy this deficiency. That scheme is an extension of the FDTD standard Yee cell and stencil that includes not only the usual, physical fields but also auxiliary, unphysical fields allowing a straightforward application of moving boundary conditions. The proposed scheme is illustrated by four examples - a moving interface, a moving slab, a moving crystal and a moving gradient - with systematic validation against exact solutions.
RESUMEN
This paper presents a space-time-wise orthogonal analysis of space-time crystals. This analysis provides a solution consisting of a pair of explicit parametric equations that result from a separate application of the Bloch-Floquet theorem in the (orthogonal) directions of space and time. Compared with previous approaches, this solution offers the benefits of greater simplicity, clearer emphasis on space-time duality, and deeper physical insight.