Causality relations in the homogenization of metamaterials

摘要: We investigate the causality relations in homogenized metamaterial arrays and determine reasons why effective (bulk) constitutive parameters obtained using classic point-dipole approximations may violate basic conditions represented by Kramers-Kronig relations. show that noncausality is inherently introduced use of within Maxwell-Garnett homogenization procedures these artifacts become particularly significant for more densely packed arrays. In contrast we properly defined exactly computed bulk periodic always satisfy a fixed spatial frequency rigorous framework. Finally how approach can be modified to effectively remove noncausal effects.