A demonstration of multiplicative tapering in FDTD Green’s function diakoptics

We have implemented a simulation tool for finite difference time domain (FDTD), or lattice Green’s function (LGF) diakoptics. This amounts to fully self-consistent FDTD boundary conditions for possibly disjoint computational domains. Our main focus is the multiplicative tapering of the LGFs, which results in a crucial reduction in computational and storage costs, and thus ensures the viability of LGF diakoptics. We show that a simple truncation is not sufficient. Instead we show the effectiveness of using a Hann window for both a homogeneous setup and a configuration with a large dielectric contrast.