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The optimization of difference patterns of monopulse antennas is considered. The synthesis problem is recast as an optimization problem by defining a suitable cost function. In particular. in this paper, the cost function is based on constraints on the side-lobe levels. A subarray configuration is adopted and the excitations of the difference pattern are approximately determined. The optimization problem is efficiently solved by a differential evolution algorithm, which is able to contemporarily handle real and integer unknowns. Numerical results are reported concerning classical array configurations previously considered in the literature

--This paper presents an approach for the optimization of the beam pattern produced by massively thinned arrays. The method, which combines the most attractive features of a genetic algorithm and those of a combinatorial technique (namely, the Difference Sets Method), is aimed at synthesizing massively thinned antenna arrays in order to suitably reduce the peak side-lobe level. Selected numerical results are presented in order to assess the effectiveness and reliability of the proposed approach.

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Abstract.By using an inductive procedure we prove that the Galerkin finite element approximations of electromagnetic eigenproblems modelling cavity resonators by elements of any fixed order of either Nedelec's edge element family on tetrahedral meshes are convergent and free of spurious solutions. This result is not new but is proved under weaker hypotheses, which are fulfilled in most of engineering applications. The method of the proof is new, instead, and shows how families of spurious-free elements can be systematically constructed. The tools here developed are used to define a new family of spuriousfree edge elements which, in some sense, are complementary to those defined in 1986 by Nedelec.Mathematics Subject Classification. 65N25, 65N30, 65N12.