A Technique for Reducing the Numerical Dispersion of Conditionally and Unconditionally Stable FDTD Methods

We present an approach to reduce the numerical dispersion of the FDTD method for its conditionally and unconditionally stable implementations. Significant reduction of the numerical error is achieved in a wide frequency band and for low spatial sampling rates. The cancellation of the numerical dispersion errors is achieved by the proposed combination of second order and higher order finite-difference approximations for the spatial derivatives of Maxwell's equations. Also, the proposed update schemes are more accurate and faster than the corresponding higher order FDTD schemes for the same time-space discretization. Finally, test examples are provided for validation and verification purposes.