Reciprocity Principle for Stable Subgridding in the Finite Difference Time Domain Method

In this paper we present a method to analyze stability of the Finite Difference Time Domain schemes containing locally refined meshes. The method relies on the reciprocity principle derived from the operator approach to stability analysis and is an alternative to popular stability tests that are either time-consuming or difficult to implement. The proposed approach is verified in numerical tests which prove that verification of stability of any subgridding algorithm can easily be performed using reciprocity principle.