Determination of the electromagnetic properties of chiral composites using normal incidence measurements

This thesis presents the first complete experimental study of chiral composite materials at microwave and millimeter wave frequencies. The samples prepared are artificial chiral composites realized by embedding either right- or left-handed helices in an epoxy host material. This is in contrast to naturally occurring molecular or even atomic chirality which affects the propagation of EM waves at optical frequencies resulting in optical rotation and optical dichroism (collectively called optical activity). The electromagnetic field behavior in materials with a handed microstructure is readily described by the use of the constitutive relations D = ;A complete experimental characterization of chiral composite samples was attempted in the 8-40 GHz frequency band and has been successfully completed. In addition valuable insight has been obtained on the relationship between microstructural chirality and the resulting macroscopic electromagnetic properties. The chirality parameter has been measured directly for the first time for several different samples as a function of frequency.