Research Specifications

Design and behavioral-model-based nonlinear analysis of a 3-GHz active-phased array antenna (APAA) are presented. Four nonlinear power amplifiers are employed in the output ports of the feeding network (FN) and analyzed based on a 5-order polynomial model with frequency-dependent coefficients. The FN is based on 4-port new Gysel power dividers and combiners arranged in such a way to feed the array with Gaussian-like amplitude and in-phase distributions. Beam steering capability is obtained in 2 directions by a new technique including a phase shifter and an amplitude controller (AC). The features result in a low-profile APAA whose design and fabrication complexity and cost are reduced. Single and 2-tone power tests are performed to develop analytical expressions in nonlinear region for array factor as a function of the model, FN and the phase and ACs. A similar system with frequencyindependent model is also analyzed for comparison in terms of scan loss, beamwidth, side-lobe level, beam position, and gain. A microstrip array antenna including the power amplifiers, pre-amplifiers, AC, delay-line-based phase shifters and Gysels is fabricated and measured. The simulation results at the single and dual tones and the intermodulation products are presented which have a good agreement with the measurements.