Problem-matched basis functions for microstrip coupled slot arrays based on transmission line green´s functions (TLGF)

A method is proposed for the analysis of arrays of linear printed antennas. After the formulation of pertinent set of integral equations, the appropriate equivalent currents of the Method of Moments are represented in terms of two sets of entire domain basis functions. These functions synthesize on one side the resonant behavior of the slot, microstrips or dipole and on the other side the field in proximity of the feeding source and of the discontinuities. In order to define these basis functions, canonical geometries are identified, whose Green´s functions have been found in semi-analytical form. The accuracy and the effectiveness of the method in terms of convergence rate and number of unknowns is demonstrated by comparison with a standard fine meshing full-wave analysis. The method is extremely convenient for large arrays where the details of the feed are very small in terms of the wavelength. Since the proposed solution is independent on the dimensions of these details, it provides a dramatic reduction of the number of unknowns with respect to a standard fine mesh analysis.