Choice of grid configuration of array antennas

The variation of the area occupied by each element of a 2-dimensional planar array with the change in the base angle of a isosceles-triangle grid is investigated. It is shown that the nearest grating lobes interchange their positions on each side of a (base angle of isosceles triangle) equal to 60°. A general formula for the percentage saving in the number ot elements is found. The analysis shows that the percentage saving increases very sharply below ¿ = 30° and for ¿ > 63° 27¿ no saving is possible.