SCATTERING OF ELECTROMAGNETIC-WAVES BY HELICES AND APPLICATION TO THEMODELING OF CHIRAL COMPOSITES .2. MAXWELL-GARNETT TREATMENT

The average polarizabilities of a helix are computed using the far-fie ld forward and backward scattering amplitudes, and subsequently used f or deriving the constitutive parameters of helix-loaded composites via a Maxwell Garnett treatment. Computational results are first compared with some results obtained earlier with other effective-medium theori es. Then, Maxwell Garnett estimates for the effective properties of se veral helix-loaded materials (chiral and transversely bianisotropic un iaxial composites) are compared with experimental data measured by the means of a free space bench in the 6-18 GHz range. Numerical and expe rimental determinations of the rotation angle, ellipticity, chirality parameter, permittivity, and permeability are presented and discussed in detail. Results for the reflection and transmission coefficients of helix-loaded slabs and the reflection coefficients of metal-backed sl abs are also presented.