A simplified PML for use with the FDTD method

A recent advance in the use of the finite-difference time-domain (FDTD) method has been the introduction of the perfectly matched layer (PML) to act as the absorbing boundary condition. This letter suggests using fictitious magnetic and electric displacement (as opposed to electric field) conductivities in order to better isolate the PML from the rest of the FDTD problem. It further describes the implementation for the PML directly from the FDTD formulation itself. This results in an analysis that is much easier to understand and to program.