Analytical antenna model for chiral scatterers: comparison with numerical and experimental data

An analytical model for polarizability dyadics of small chiral conductive particles in free space or those embedded in a lossy material is presented and discussed. Chiral particles are modeled by a wire loop connected to two straight wire elements. The electromagnetic analysis is based on the replacement of the particles by two connected antennas representing the wire and loop portions. Analytical expressions for polarizabilities are given. For electrically small particles, a lumped-element equivalent circuit can be constructed and the polarizabilities can be expressed in terms of equivalent circuit parameters. It is shown that the wire-and-loop antenna model for scatterers satisfies the reciprocity condition and other basic physical requirements. Approximate analytical expressions are compared with numerical simulations and with the experimental data on reflection from single chiral particles, and the results are seen to be in good agreement. The model can be used in analytical modeling of chiral and omega composite materials.