S.P. Skobelev

Radiating elements in the form of large-aperture horn and reflector antennas find important application in highly directive phased antenna array designed for scanning in narrow angular regions of space. In the present paper, a quantitative analysis of the effectiveness of using similar antenna elements in planar singly and doubly periodic phased arrays is carried out. The indicated effectiveness is defined as a ratio of the minimum number of elements necessary for satisfying requirements specified for the array gain within a specified field of view to the actual number of the large-aperture elements. In case of singly periodic arrays, the elements with uniform and cosine-tapered amplitude distributions over aperture are considered. It is shown that in each case there exists an optimal relation of the actual array element spacing to the maximum possible element spacing corresponding to the specified field-of-view width providing maximum of element use effectiveness. It is found that the maximum element use effectiveness corresponding to the cosine distribution is approximately 40% higher than the maximum efficiency corresponding to the uniform distribution. The indicated arrays are compared to the arrays where the known single-cascaded chess-board circuit is used for forming a sector element pattern. It is shown that the maximum element use effectiveness in case of the arrays with the sector element patterns is by 12-to-16% higher than the maxim effectiveness corresponding to the non-coupled elements with cosine distribution. In the doubly periodic arrays, there are considered elements with hexagonal and circular apertures arranged in a hexagonal lattice, as well as elements with square and circular apertures arranged in a square lattice. It is shown that the element use effectiveness for the indicated elements with uniform aperture distribution does not exceed 37.5%. It is also shown that the use of a quadratic tapered distribution over a circular aperture element allows increasing the element use effectiveness up to 42.85% independently of the lattice type.