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C ONCLUSIONS
A novel approach based on the use of a multi-objective algorithm has been applied to the synthesis of wideband planar sparse arrays. Particularly two array layouts, i.e. elements arranged in concentric rings and spirals, have been taken into account. By analyzing several design examples, it has turned out that both the configurations possess good wideband performance as well scanning capabilities. Furthermore, referring to the feasibility, being defined analytically by numerical rules, either the CRA or the spiral array succeed in creating a sparse aperiodic arrangement of radiating elements in an easier manner than the completely randomised ones, thus reducing manufacturing costs.
With regard to designing a wideband single-element antenna, the dissertation has proceeded with developing an efficient method for optimizing such a wideband antenna.
Particularly a two-stage genetic algorithm has been employed along with the MoM for the synthesis of a loaded miniaturized wideband antenna in presence of any scatterers. Thus, the method here developed has shown the possibility to include a priori mutual coupling effects due to the complex environment. Also in this case, particular attention has been paid to the manufacturing process, thus reducing the allowable values of the matching RF components to those which are available commercially and operate inside the considered bandwidth.
In the final dissertation, conformal antenna arrays have been treated. Particularly, by mean of the spectral rotation technique, a MM/FEM/MoM hybrid approach has been described and implemented with the aim of analyzing arrays of apertures mounted on a infinitely long perfectly electric conducting circular cylinder. This method has proven to be an effective tool for analyzing any arbitrarily-shaped aperture antennas even loaded somehow, i.e. dielectrics, corrugations, irises.
Moreover, two synthesis techniques have been applied to the synthesis of the
aforementioned conformal array of aperture antennas. Particularly, the method of alternating
projections has been jointly employed with the LMS technique in order to synthesize a power
radiation pattern meeting certain requirements in terms of a not-to-exceed radiation mask. The
method has been also extended to deal with the mutual coupling issues. Finally, an effort for
improving the bandwidth of a conformal antenna array, based on the RPS-approach, has been
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