Measurement and prediction of helix-loaded chiral composites

A method is described for the extraction of the permittivity, permeability, and chirality of composite chiral materials, using measurements of reflection and transmission in a circular waveguide. This has been applied to a number of helix-loaded composites, in the frequency band 8-12 GHz. The properties of these composites have also been computed from the helix geometry and other basic information. The theory correctly predicts the frequency of the half-wavelength resonance observed, the relative magnitude of the constitutive parameters, and the low-frequency dielectric constant. But it has been found necessary to adjust the host-medium loss to obtain the correct absolute magnitudes. This agreement provides a confirmation that the theory is basically sound and so assists in discovering what chiral parameters are practically obtainable and in exploring applications of chiral materials.