Influence of helix parameters on the reflectance of microwave by chiral composites

We prepare planar chiral composite samples containing a random distribution of helixes of different parameters. The influence of the helix parameters on the reflectance of microwave energy by chiral composites is studied. The helix parameters include the helix diameter, the pitch, and the gauge diameter. The reflectance of the microwave by metal backed chiral samples is calculated from the complex permittivity, complex permeability, and complex chirality parameter measured with ordinary microwave circular waveguide measurement system in the frequency range of 8.5-11.5 GHz. The results show that the helix diameter, the pitch, and the gauge diameter have remarkable influence on the reflectance of microwave energy by chiral composites. There exist optimal helix parameters in order to obtain the lowest reflectance.