A Bifocal Focused Two-Dimensional Frequency-Scanned Array

A 2D frequency-scanned array focused in the near-field zone is analyzed. A method for the synthesis of this array ensuring perfect field focusing in two points at two frequencies is proposed. Array scanning in two planes (longitudinal and transverse) is analyzed with the use of an approximate model. The motion trajectory of the focal spot (scanning arc) and optical aberrations associated with scanning are studied. Different variants of determination of the scanning arc, using the criterion of the maximum field intensity and the criterion of the maximum aperture efficiency of the array, are considered. It is shown that application of bifocal arrays can improve main quality indices as compared to those of single-focus arrays.