A new radiation boundary condition for FDTD based on self-teleportation of fields

A technique for injecting perfect plane waves into finite regions of space in FDTD has been reported. The essence of the technique, called field teleportation, is to invoke the principle of equivalent sources using FDTD´s 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 domain itself to create a boundary across which any outward traveling FDTD field produces an exact negative copy of itself. Repeated application of this radiation boundary and termination of the domain with a moderate absorbing boundary condition readily yields reflection coefficients of the order of -80 dB up to grazing incidence onto the boundary.