Hybrid MoM-high frequency analysis of large arrays of printed dipoles

Printed periodic antenna technology is becoming increasingly popular for its well known advantages, exhaustively discussed in the recent literature. The estimation of the phased array parameters is often based on the hypothesis of infinite structure; this allows the expansion of the fields in terms of Floquet waves (FWs), thus reducing the analysis to that of a single cell of periodicity. The infinite array approximation leads to reasonable results in predicting the behavior of elements far from the array edges, but is significantly inaccurate near the edges. On the other hand, a rigorous analysis based on an element-by-element method of moments (MoM) becomes computationally prohibitive when the size of array increases. An approximate while accurate alternative method consists of adding to the infinite array current an edge perturbation which may be rigorously estimated by solving via MoM an appropriate "fringe" integral equation (FIE). In this scheme, the perturbation current is expanded in terms of few basis functions with domain on the entire array aperture which are based on a ray-diffraction representation of the pertinent array Green\´s function (AGF). The theoretical basis of the method is given in a series of recent papers, which systematically generalize to finite arrays the FW representation of infinite periodic arrays, by introducing diffracted rays arising from array edges and corners from both free-space and stratified environment. On the basis of the asymptotic AGF, the method is extended here to the problem of rectangular periodic array of printed dipoles on a grounded dielectric slab illuminated by an incident plane wave.