A comparison between the FDTD convolutional PML and reradiating boundary conditions for simple 3D test problem

Abstract

In this paper we provide a field termination performance comparison between convolutional PML and reradiating FDTD boundary conditions for simple numerical experiment. It is shown that for the 3D case a simple stackable re-radiating boundary condition (R-RBC) competes with a convolutional perfectly matched layer (CPML). The essence of the R-RBC which based on Field Teleportation technique, is to invoke the principle of equivalent sources using FDTDpsilas discrete definition of the curl to copy any field propagating in one FDTD domain to a finite region of another domain. In this paper we apply this technique of field teleportation to the original 3D domain itself to create a transparent boundary across which any outward traveling FDTD field produces an exact negative copy of itself causing self-canceling. Relatively thin (5 cells) RRBC readily yields absorption of the order of -80 dB in 3D ldquoanechoic chamberrdquo test whereas CPML shows similar performance for a 20-cells layer.