Wave propagation through scattering structures made by cascading screens of finite thickness

In a genuine three-dimensional context, we study analytically the scattering properties of a cascading structure made by plane, parallel and equi-spaced screens, each one having the same (periodic) distribution of identical openings of rectangular shape. Differently from previous paper, the screens are supposed to have a common non-null thickness, which implies a double number of governing equations and systems. By using suitable approximations involving physical and geometrical parameters, we get explicit representations with respect to frequency for the scattered wave field and the relevant parameters. To show and discuss the peculiar properties of the structure, some figures are finally provided.