Modeling arbitrarily directed slots that are narrow both in width and depth with regard to the FDTD spatial cell

The hybrid thin-slot algorithm (HTSA) integrates a transient integral-equation solution for an aperture in an infinite plane into a finite-difference time-domain (FDTD) code. A general implementation for arbitrary thin slots is described. The 3-D FDTD code TSAR was selected for the implementation. The implementation of the HTSA into TSAR is based on a slot data file that includes the cell indices where the desired slots are to exist within the FDTD mesh. For an HTSA-defined slot, the wall region local to the slot is shorted, and, therefore, to change the slot´s topology simply requires altering the file to include the desired cells. Results are presented for a rectangular hatch-type aperture coupling into a rectangular cavity.<>