Study of laminated dielectric behavior at microwave and millimeter-wave frequencies

Dielectrics composed of layers of different dielectric constant have radome applications. A laminated or layered structure can be used to improve mechanical and thermal properties, while a certain amount of dielectric-constant tailoring can be done by varying the layer permittivities and their relative thicknesses. Such a multilayer system (sometimes called an artificial dielectric) is basically uniaxially anisotropic with the optic axis perpendicular to the planes of lamination, although this anisotropy may not be large, depending on the layer permittivities and thicknesses. In any case, the equivalent static dielectric constants for a laminated structure are readily calculated, provided the layer constants and thicknesses are known, by use of a model involving parallel and series capacitances. In this paper we explore the range of validity of the artificial-dielectric model comparing its computed results with those obtained from an N-layer flat-panel computer program for a number of specific multilayer dielectric structures.