Engineering Physics

6.9 Frequency dependence of dielectric constant

The permittivity (∈) of a dielectric material is equal to ∈₀∈_r. Where ∈_r is called relative permittivity or dielectric constant of the material and ∈₀ is the permittivity of free space. Also from Clausius-Mosotti relation, we know that the dielectric constant is related to polarizability of the material. So, we can see the variation of permittivity and hence relative permittivity or, dielectric constant, in turn, polarizability of a dielectric material with the frequency of the applied electric field. The fall in the permittivity of a dielectric material with increasing frequency of the applied electric field is usually referred to as anomalous dispersion.

The behaviour of a dielectric material ...