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Specifying PML Conductivities by Considering Numerical Reflection Dependencies
2000 Award Winner
Charles W. Bostian, Center for Wireless Telecommunications
William T. Brandon, The MITRE Corporation
Alfred U. MacRae, Consultant, Telecommunications and Satellite Technology
Christoph E. Mahle, Consultant, Washington, DC
Stephen A. Townes, Jet Propulsion Laboratory
ABSTRACT
Berenger's perfectly matched layer (PML) absorbing boundary condition (ABC) has greatly enhanced finite-difference time-domain (FDTD) scattering analysis. In a discretized domain, however, performance is signal-dependent and large-angle performance is poor due to a rapid reduction in layer decay rate. Increasing the conductivity to offset this reduction increases the discretization errors, especially at near-normal incidence angles. However, by carefully specifying the conductivity in each of the PML sublayers, it is possible to balance the small and large angle performance. The signal-dependence of reflections may be described in terms of the number of spatial points per wavelength. This lends itself to an overall strategy for which to search for PML profiles that provide superior performance for waves incident on a PML at angles between 0-75° and signals that have at least 15 spatial points per wavelength sampling. A one-dimensional (1-D) projection method may be employed to allow an exhaustive search to become a viable alternative to optimization. Such a search provides profile parameters that, while not necessarily "optimal," give excellent wide-angle wide-band reflection performance.
Publication
Published in 2000 ©IEEE. IEEE Transactions on Antennas and Propagation, Vol. 48, No. 7, pp. 1055-1063.
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Additional Search Keywords
finite-difference time-domain (FDTD) methods, perfectly matched layers (PMLs)
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