Dielectric polarization mechanism charge carriers

In general, the dielectric constant is a complex quantity, k = k — Ik". The dielectric constant k is controlled by the conductivity at very low frequencies, and by various polarization mechanisms at higher frequencies. Electronic polarization and molecular dipole moments can be estimated from the refractive indices and dielectric constants. The dissipation factor D = k" k of a dielectric is sensitive to charge carriers and reorientable dipoles. Accurate loss measurements are capable of detecting free-carrier concentrations of 10 /cm. Various contributions to the loss can be separated by determining the dependence on temperature and frequency. 

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