Enhancement of the dielectric constant near a percolation threshold

When one of the components of a mixture of two materials is a conductor, geometrical effects can lead to a dielectric constant for the mixture which is much greater than that of either constituent. Here we illustrate a simple example of this effect in a two-dimensional network consisting of randomly placed conductors and capacitors. The dielectric enhancement is obtained as a function of frequency and the concentration of conductors. The calculational technique used is the position-space renormalization group in which smaller units are combined iteratively to form larger units.