Landau theory of ferroelectric thin films and its relevance to RF filter design

The authors pay particular attention to how the polarization profile can be calculated and then show how, via the Landau-Khalatinkov equations, the response to an incident electromagnetic field can be calculated. Obviously, this is just the sort of information relevant to filters design in the sense that it is essentially the response to an electromagnetic field that is important, especially the wave nature apparent at high enough frequencies.