Intrinsic electrostatic resonances of artificial dielectric heterostructures

We develop an efficient effective-medium-based method for modeling the effective permittivity, with careful attention paid to several key factors controlling electrostatic resonances (ERs) of artificial dielectric heterostructures. Our method relies on FE modeling and is applicable to inclusions with complex boundaries. A series of square arrays of several types of negative-permittivity media are considered. The inclusion shapes investigated can be considered as cross sections of infinite three dimensional objects, where the properties and characteristics are invariant along the perpendicular cross sectional plane. The continuum model used in this work is accurate only if the homogeneous representation of the composite structure makes sense, i.e. quasistatic approximation. For lossy inclusions, the primary signature of the ER is seen in the peak in the imaginary part of the complex permittivity or as an inflexion in the curve of the real part of the complex permittivity. The higher the iteration number of the inclusion the smaller value of ¿2 corresponding to the ER. In the vicinity of the ER peak, field enhancement are observed, which consist of enormous changes in the local electric field.