Study and development of printed circuit elements for synthetic aperture radar array antennas

A general presentation of the state-of-the-art on planar array antennas is combined with a technical discussion and selection of the best suited elements for circular patch and slot-stripline radiators. The mutual coupling between radiators in several types of 1 X 8 arrays with circular patch elements was examined to optimize the distances between them in the complete SAR array antenna. A simple microstrip feeding network with low permittivity substrate, easy to realize by photoetching was designed and measured. The impedance and radiation pattern of a 2 x 8 subarray fed by the preceding network was measured. The performance of elementary radiators concerning resonant frequency, impedance, bandwidth, radiation pattern, polarization, and efficiency were studied. The advantages and disadvantages and the influence of mechanical tolerances on their electromagnetic behavior was investigated.