Effect of Parameter Variations on the Electromagnetic Response of a Metafilm Comprised of Resonant Elements

Graduate Thesis Or Dissertation

Citations

Citeable URL: https://scholar.colorado.edu/concern/graduate_thesis_or_dissertations/pc289j182

Abstract

A metafilm is a 2-dimensional version of a metamaterial which consists of a single layer of resonators. The elements resonate with changes in frequency and are arranged periodically in an array. In this thesis, a theory describing the characteristics of arrays of resonant scatterers is thoroughly developed using analytical techniques (which have the advantages of providing physical insight and being computationally inexpensive) and demonstrated by numerical analysis. The analysis is based on a dipole interaction model, and is validated using independent full-wave numerical simulations. The technique derived in this work, the interaction polarizability approximation, takes into account variations in the parameters of the elements in such a way that it can accurately predict both weak and strong coupling. For a metafilm, this leads to expressions for reflection and transmission coefficients that correctly predict the existence of Fano bands. Experimental measurements are carried out that confirm the existence of Fano resonances for a metafilm mounted in a waveguide, bearing out the practical significance of the predictions of this thesis. This thesis demonstrates that the Fano bands, or regions of rapid asymmetric frequency variation in an otherwise smooth curve, are not simply the result of measurement errors but are in fact an inherent behavior for a metafilm, one that simply results from manufacturing errors that cause variations in parameters that affect resonant behavior.

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