Date of Award

January 2017

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics & Astrophysics

First Advisor

Graeme Dewar

Abstract

Negative index materials (NIM) are artificial structures in which the refractive index for light has a negative value over some frequency range. This does not occur in any known natural materials, and thus is only achievable with engineered structures known as metamaterials. Metamaterials demonstrating a negative refractive index for light usually consist of arrays of wires and cut-ring structures: such media are characterized by both the electrical permittivity and magnetic permeability being negative. My method for obtaining a NIM is different from previous attempts. I get the negative magnetic permeability from a ferrite material which is the host medium for the wire array. The ferrite plus wires array creates a NIM in the microwave frequency range. One important consideration involves decoupling the ferrite and wire array’s response to incident microwaves. Experiments involving transmission and reflection of microwaves through, and from, a ferrite / wire array metamaterial inside a waveguide demonstrates that 𝑛<0 over a frequency range tunable by adjusting an externally imposed static magnetic field.

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