Tunable filter using ferroelectric-dielectric periodic multilayer.

The microwave optical properties of a photonic crystal-based tunable single and multichannel filter are theoretically investigated using the transfer matrix method, finite difference time domain method, and the plane wave expansion method. By applying an external voltage of 8  V/micron about a 35% frequency tuning is obtained. It is found that the number of transmission peaks is directly proportional to the number of periods (N). In addition to this, the dependence of layer thicknesses, angle of incidence and polarization are also analyzed, and it is noticed that the filtering frequency is invariant in angle and polarization.