Analysis of large aperture antenna arrays using a hybrid mode matching/characteristic basis functions method

Abstract

Finite arrays of waveguides and horn antennas are widely used both as direct radiators as well as feed clusters for reflector antennas. Accurate and efficient numerical simulation techniques represent a powerful tool for the design of such antennas. Many approaches have been proposed in the literature that employ hybrid techniques to efficiently analyze both the interior waveguide problem and as well as their coupling to the outer free space [1]–[3]. The mode matching (MM) is used to compute the generalized scattering matrix (GSM) for the inner waveguide problem, whereas the Method of Moments (MoM) evaluates the GSM for the outer free space coupling. When the array is electrically large in terms of number of elements or radiating apertures dimensions, the applicability of this approach is limited because the associated MoM matrix is large. Some novel approaches have been proposed in the literature to reduce the matrix size [4]. Recently the Characteristic Basis Function method (CBFM) [5] has been proposed to solve electrically large problems by using a set of high-level basis functions, called CBFs, that are physics-based and tailored to the problem.