A general projection approach to array synthesis

Abstract

The authors present an array factor synthesis procedure which makes it possible to specify the sidelobe and shaped-zone ripple levels as well as the fall rate of the main lobe. The problem is formulated as the search for the intersection between two suitable sets and is solved by an iterative projection method. The presence of excitation constraints can be very easily dealt with. The whole method lends itself to a very efficient implementation requiring no more than two fast Fourier transforms each step. In order to test the presented procedure, the authors synthesized a cosecant beam, to be realized with an array of 17 elements with a maximum ripple, in the shaped zone, equal to +or-0.4 dB and a sidelobe level of -30 dB. All the examples shown fulfil the constraints both on the pattern and on the excitations.>