Date of Award


Document Type


Degree Name

Master of Science in Electrical Engineering


Department of Electrical and Computer Engineering

First Advisor

Michael J. Havrilla, PhD


A new single stepped-iris waveguide technique is used to nondestructively determine the permittivity and permeability of conductor-backed media. This thesis will demonstrate a proof-of-concept that obtains two independent reflection measurements with a magnetic radar absorbing material (magRAM). Using a two measurement procedure, in which, the first measurement will apply a single rectangular waveguide to a known conductor-backed absorbing material under test (MUT) and the second measurement will insert a stepped-iris in between the single rectangular waveguide and MUT reducing the aperture to retrieve two independent electromagnetic properties (i.e. permittivity and permeability). The theoretical reflection coefficients are obtained using a rigorous full-wave solution combined with a mode matching method at the waveguide and iris regions. Additionally, a root search algorithm is used to extract electromagnetic properties of magRAM by comparing the theoretical and experimentally measured reflection coefficients. The experimental measurements of a commercial magRAM using a network analyzer will demonstrate the feasibility of the stepped-iris approach. Plots of the extracted permittivity and permeability of the MUT are analyzed to validate the stepped-iris material characterization technique.

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