Investigations on mutual coupling effects in polarimetric conformal patch-arrays

A typical application for microstrip antennas is their use in circular arrays, conformal to cylindrical structures. System performance of those arrays relies on the possibility of azimuthally omnidirectional beamforming. Mutual coupling in arrays gives rise to deviations in antenna element patterns compared with those of corresponding isolated elements. Beamforming for circular arrays depends on the form of the assumed element patterns. It must be matched to the actual element pattern of an array, taking coupling into account. Any beamforming for circular arrays which is adapted to the pattern of the isolated array element (no coupling) is mismatched to the actual array and will show a poorer performance. In view of modern polarimetric radar-applications, arrays with two port microstrip antenna elements have to be considered, and beamforming has to deal with co- and cross-polar patterns. The article deals with a corresponding investigation of coupling effects in circular, polarimetric X-band arrays