Analysis of Large Microstrip-Fed Tapered Slot Antenna Arrays by Combining Electrodynamic and Quasi-Static Field Models

Abstract

A reduced-order model for large arrays of microstrip-fed tapered slot antennas (TSAs) is presented. The currents on the antenna conductors are modeled by a relatively small number of physics-based macro-domain basis functions through a technique which is known as the characteristic basis function method (CBFM). The array is treated as a metal-only structure, while the wideband microstrip feeds are separately modeled using quasi-static circuit models. It is demonstrated that, even though the dielectric-supported feeds are non-shielded and therefore form an integral part of each radiating antenna element, the feeds can be modeled independently from the strongly coupled antenna elements. Validation of the combined antenna-feed model has been carried out through the measurements of several practically realized TSA arrays, among them a 8 × 7 × 2 dual-polarized array. The results demonstrate good agreement over a large scan range, as well as over a wide frequency band. The polarization-discrimination capabilities of the antenna, when operating in phased-array mode, have been analyzed in the context of radio-astronomical applications.