V.A. Balagurovskij - Head of Special Design Bureau, STC "Altair" JSC "MSDB "Almaz-Antey -
A.S. Kondratiev - Ph.D. (Eng.), Senior Research Scientist, Leading Specialist of Special Design Bureau, STC "Altair" JSC "MSDB "Almaz-Antey?. E-mail: info@raspletin.ru
N.P. Polishchuk - Ph.D. (Eng.), Senior Research Scientist, STC "Altair" JSC "MSDB "Almaz-Antey?

Capabilities for the control of the width of the normalized error function (NEF) of a transmissive phased array antenna (PAA) with spatial excitation are studied and the influence of the PAA geometrical structure on the PAA parameters is analyzed. Two PAAs with almost identical overall dimensions are considered: 1. A regular PAA of hexagonal configuration containing 5941 elements with hexagonal grid. 2. A nonequispaced PAA containing 6031 elements with a regular block at the center and peripheral elements arranged along the branches of a multiturn spiral. In both cases, the average interelement spacing is 0.67λ, where λ is the wavelength. Radiation patterns of PAA elements coincide with the pattern of uniformly excited aperture with a diameter of 0.67λ. The PAA is illuminated by two aperture feeds placed at a given distance R from the PAA plane, which are shifted symmetrically relative to the normal to the center of the PAA plane by distance S. The radiation pattern of each feed coincides with the pattern a of circular plane aperture with tapered aperture distribution. The diameter of the feed aperture is chosen so that the first null of the pattern of a feed placed along the normal to the center of the PAA plane is directed toward the edge of the PAA aperture and ensures zero illumination level. The amplitude-and-phase distribution of the currents on PAA elements is assumed to be coinciding with the amplitude-and-phase distribution of the tangential component of the feed field. The capability of control of the NEF width by introducing an additional phase shift in the PAA phase shifters that partially or completely compensates for the phase distribution created by the field of the non-shifted feed placed along the normal to the PAA center is studied. The influence of the structure of the PAA aperture on parameters of the NEF is analyzed. The possibility of variation in the NEF width via introduction of an additional phase shift in the PAA phase shifters is noted. The results of numerical simulation are presented.