Efficient semi-analytical method for the analysis of large finite connected slot arrays

Abstract

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.