Accuracy and efficiency of PWTD enhanced exact radiation boundary conditions in FDTD simulations

Global exact radiation boundary conditions (ERBCs) can be imposed on arbitrarily shaped truncation boundaries; hence, when using an ERBC in the analysis of slender concave scatterers the cost of updating the volume scales as O(N/sub t/N/sub s/). However, the application of ERBCs requires the evaluation of retarded-time boundary integrals (RTBIs) to update the boundary fields at a cost that scales as O(N/sub t/N/sub s//sup 2/). This unacceptable cost can be reduced to O(N/sub t/N/sub s/log/sup 2/N/sub s/) by using the multilevel plane-wave time-domain (PWTD) scheme. This paper compares the accuracy and efficiency of PWTD enhanced ERBCs and PMLs when applied to slender concave scatterers.