Conditions for the synthesis of array and aperture antennas with a unique phase center

Far-field phase characteristics, in addition to far-field amplitude characteristics, are important in connection with many applications for antennas, and procedures utilizing an antenna as a sensor for the conduction of distance and positional measurements require a unique phase reference point, the phase center. The selection of suitable antennas for the considered applications can be based on one of two approaches, including the determination of the phase center for a given antenna, and the design of an antenna with dimensions which ensure the existence of a unique phase center. The present investigation is concerned with an implementation of the second approach. The resulting problem corresponds to the determination of the illumination for given far-field phase patterns. Attention is given to the requirements which have to be satisfied, taking into account the phase center of linear antennas, antenna arrays, and aperture radiators.