Reflection characteristics of a PML with a shallow corrugation |
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Authors: | Inchaussandague ME Gigli ML Depine RA |
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Affiliation: | Grupo de Electromagnetismo Aplicado, Univ. de Buenos Aires, Argentina; |
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Abstract: | The constitutive characteristics of anisotropic materials can be exploited to construct absorbers that provide reflectionless interfaces for waves at arbitrary angles of incidence. In this paper, we investigate how a weak corrugation affects the reflectivity of the anisotropic perfectly matched absorber developed by Sacks et al. (1995) for a flat interface. To do so, we develop a Rayleigh method to calculate the fields diffracted at the periodically corrugated boundary of an anisotropic absorber with constant constitutive tensors, which correspond to a planar (Cartesian) perfectly matched layer. We present numerical results in the nondiffractive regime (where only a specularly reflected wave can propagate) for sinusoidal corrugations with different groove height-to-period ratios. Our results show that the reflectivity of the anisotropic absorber near normal incidence remains very low (less than 0.4% for a 10% modulation), whereas it changes dramatically near grazing incidences. |
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