Incorporation of a feed network into the time-domain finite-element modeling of antenna arrays

An accurate and efficient numerical scheme is presented for incorporating a feed network into the time-domain finite-element modeling of antennas and antenna arrays. The feed network is represented in terms of a rational function form of its scattering matrix in the frequency domain that enables its interfacing with the time-domain finite-element modeling of the array through a fast, recursive time-convolution algorithm. The exchange of information between the antenna elements and the feed network occurs through the incident and reflected modal voltages/currents at properly defined port interfaces. The proposed numerical scheme significantly simplifies the simulation of an antenna system that comprises both antennas and a feed network and allows one to fully utilize the power of an antenna simulation technique to deal with large and complex antennas. Several examples are presented to demonstrate the accuracy and efficiency of the method.