We present an efficient method to analyze a periodic pin-patch structure, consisting of two artificial dielectric layers (ADLs) connected by vertical metal pins. ADLs are made of square metal patches in a periodic lattice and have recently been used as superstrates in antennas and arrays to enhance the bandwidth and scanning range. ADLs form an anisotropic effective medium, thus enabling a large scanning volume without supporting surface waves. However, the anisotropy increases the cross-polarization (X-pol) of the antenna in the diagonal plane. This problem can be reduced by introducing vertical metal pins in the ADL superstrate to form the pin-patch structure. The analysis method is based on a spectral method of moments (MoMs) and uses entire-domain basis functions in a hybrid Cartesian and cylindrical representation to accurately model the currents on the structure and scattering parameters under general plane-wave incidence.

The characteristic cross-polarization (X-pol) of wide angle impedance matching (WAIM) structures is investigated. The study considers an ideal linearly polarized current sheet in the presence of various dielectric and artificial dielectric superstrates, analyzed using transmission line models representing the stratified media. The main mechanism that causes increased X-pol is highlighted and linked to the anisotropy of the superstrate. We then propose an approach to reduce the X-pol by including vertical vias within the WAIM dielectrics, to control the vertical component of the permittivity tensor. The intrinsic X-pol performance of a set of artificial dielectric layers (ADLs) with and without vias is experimentally verified by placing the WAIM above an open-ended waveguide that acts as a linearly polarized source. The proposed WAIM with vias can be used in wideband wide-scanning array designs to improve polarization purity.

We present an efficient method for the analysis of finite connected slot arrays in the presence of stratified media. The formulation is based on a spectral method of moments, where only one basis function is considered for each array element and one for each slot edge. An expression for the mutual impedance is derived in terms of a double spectral integral. Asymptotic extraction techniques are employed to largely reduce the computation time of one of the spectral integrals. For the other integral, when a guided wave contribution dominates the mutual coupling between two array elements, the result can be approximated as the residue of the spectral polar singularity, providing a closed-form solution of the coupling for elements at electrically large distances. The complete method enables simulations of entire finite arrays with hundreds or even thousands of elements in minutes. The same structure would require impractical computation time when analyzed with general-purpose commercial software. The method allows estimating the performance of finite connected arrays. This is particularly relevant because wideband connected arrays are known to exhibit higher edge effects compared to narrowband arrays, due to the high interelement mutual coupling.

We present the unit cell design of a wideband wide-scanning phased array operating in both Ku- and Ka-bands, for satellite communication applications. The radiating elements are dual-polarized connected slots loaded with an artificial dielectric superstrate, acting as a wide angle impedance matching (WAIM) structure. The design of the multi-layer artificial dielectric is based on analytical formulas describing the equivalent reactance of each layer, valid for geometries that are not periodic in the vertical direction. This allows to minimize the total number of metal layers composing the artificial dielectric. The predicted matching performance is investigated by means of simulations based on infinite array approximation.