An effective hybrid strategy in some array synthesis problems

Most global optimization based synthesis procedures act in essentially the same way on all the involved variables. In this communication, it is theoretically discussed and numerically emphasized how explicit exploitation of the convexity of the problem with respect to a part of the degrees of freedom (when available) allows to achieve increased performances with respect to previous results, and to develop new interesting design solutions. Examples are presented for the synthesis of sum patterns by using non-uniformly spaced linear and planar arrays and for the ´optimal compromise amongst sum and difference patterns´ problem. Finally, the proposed approach is exploited in developing effective design solutions (based on the concept of interleaved arrays) to the problem of achieving very flexible antennas while using simple feeding networks. As an example, array antennas capable to radiate two different beams with individually steerable patterns, or to perform jammer rejection at the physical layer, are synthesized and presented.