Efficient Design of a C-band Aperture-Coupled Stacked Microstrip Array Using Nexxim and Designer

Abstract

An array antenna suitable for an airborne SAR system is considered. The radiating element consists of two stacked microstrip patches that are coupled to a microstrip line by a slot in the intervening ground plane. The antenna operates at C-band, is capable of dual polarization and shows a bandwidth equal to 800MHz. This presentation details the efficient design of this antenna taking benefit from the Solver-on-Demand feature of the Nexxim and Designer simulators. Every antenna component has been designed separately with a fully parametrized model and has been easily tuned and optimized with Designer, to meet the dimensional and frequency requirements. These components include transmission lines, optimum mitered bends, particularly shaped tee junctions and the stacked patch antenna element itself. The individual components are then assembled and interconnected in the Nexxim circuit simulator to form the whole array. The assembly is tuned and optimized using the speed capability of Nexxim, but maintaining the accuracy of the full wave model assured by Designer. The Solver-on-Demand feature lets us choose which part of the antenna will be solved with a full wave analysis and which part will be solved with a simple circuit simulation. The time savings using this combined full-wave/circuit design is significant, furthermore this combination also enables improved design and more accurate results compared to those obtained applying Designer and Nexxim alone.