Design of an All-dielectric Sublayer for Enhanced Transmittance In Stacked Antenna Array Applications

In spatially constrained applications, the overlapping of antenna arrays can be unavoidable and its presence can lead to a blockage in the line-of-sight for the underlying antennas. Although previous investigations focused predominantly on the contribution of the ground plane and feed network-which were resolved through the use of frequency selective surfaces and proper feed network design, respectively-it is believed that the ground plane, substrate, and patch regions can emplace a substantial combined impedance. To rectify the transmission through these layers, an all-dielectric implementation is suggested based on the properties of complementary media and Fabry-Perot resonance shifting phenomena. Consequently, both spherical inclusion based dielectric metamaterials and regular dielectrics are suggested, such that additional conductive losses are avoided and surface wave coupling becomes less plausible; while making possible both negative and positive refractive indices. The transfer matrix method and effective medium theory are jointly implemented to examine the required properties of the dielectric or metamaterial sublayer on the basis of providing a transmittance on the order of a known high transmittance analog. Mie theory provides the basis behind the effective properties of the spherical inclusion based metamaterial whereby the required dimensions and permittivity can be determined by a sequential quadratic programming optimization in MATLAB. It is found that the metamaterial emplaces constraints on fabrication which are not currently feasible. Therefore, the equally practicable positive refractive index solutions in a regular dielectric are proposed as the most viable alternative and utilized to determine a functional bandwidth