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A FDTD subgriding based on Huygens surfaces

We present a new subgriding technique based on the use of Huygens surfaces. In contrast with previous attempts, the main grid and the subgrid are not connected directly. The connection between the grids is only a physical connection, by means of Huygens surfaces. The proposed method allows large ratios of space steps to be used without significant reflection from the grids connection. The method is not stable naturally but its principle permits stabilization procedures to be implemented.