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In this paper, a hybrid approach for the synthesis of the "optimal" compromise between sum and difference patterns for subarrayed monopulse antennas is presented. First, the subarray configuration is determined by exploiting the knowledge of the optimum difference mode coefficients to reduce the dimension of the searching space. In the second step, the subarray weights are computed by means of a convex programming procedure, which takes advantages from the convexity, for a fixed clustering, of the problem at hand. A set of representative results is reported to assess the effectiveness of the proposed approach. Comparisons with state-of-the-art techniques are also presented. [ABSTRACT FROM AUTHOR]

Synthesis of ultrawideband (UWB) antennas by means of a particle swarm optimizer (PSO)-driven spline-based shaping approach is described. In order to devise a reliable and effective solution, such a topic is analyzed according to different perspectives: 1) representation of the antenna shape with a simple and efficient description; 2) definition of a suitable description of the UWB Tx/Rx system; 3) formulation of the synthesis problem in terms of an optimization one; 4) integration of the modelling of the UWB system into a computationally efficient minimization procedure. As a result, an innovative synthesis technique based on the PSO-based iterative evolution of suitable shape descriptors is carefully detailed. To assess the effectiveness of the proposed method, a set of representative numerical simulations are performed and the results are compared with the measurements from experimental prototypes built according to the design specifications coming from the optimization procedure. To focus on the main advantages and features of the proposed approach, comparisons with the results obtained with a standard parametric approach are reported, as well. [ABSTRACT FROM PUBLISHER]

A set of representative results are presented that are obtained with two multiresolution strategies developed for dealing with multifrequency inverse scattering experiments starting from the iterative multiscaling approach previously studied for monochromatic illuminations. The first approach is concerned with the integration of the iterative multiscaling algorithm into a frequency-hopping reconstruction scheme, while the second one allows a multiresolution simultaneous processing of multifrequency data. The numerical and the experimental analysis are aimed at assessing both the reconstruction effectiveness and the required computational costs of the two- and three-dimensional implementations of the proposed inversion schemes in comparison with the monochromatic multistep process and to the single-step optimization strategy, as well. [ABSTRACT FROM AUTHOR]

In this paper a new approach to the control of phased arrays is presented and assessed. Starting from the adaptive array theory, a particle swarm strategy is used to tune the phase coefficients of the array in order to adaptively minimize/avoid the effects of interfering signals at the receiver. To show the effectiveness of the proposed approach, a selected set of numerical examples, concerned with linear as well as planar arrays, is presented. Furthermore, to evaluate the advantages of the particle swarm optimizer (PSO)-based strategy over state-of-art methods, a comparative study is carried out by analyzing the performance of the method in terms of both the signal-to-interference-plus-noise-ratio and resulting beam pattern. The achieved results, even though preliminary, seem to confirm that the PSO-based approach satisfactorily works and it generally outperforms previously proposed/state-of-art phase-only adaptive control strategies. [ABSTRACT FROM AUTHOR]

The development of efficient automotive accident management systems requires the design of complex multifunction antennas enabling different wireless services (e.g., localization, voice and data communications, emergency calls, etc.). Starting from different specifications (electrical, mechanical, and aerodynamic), the design of a multifunction antenna must consider, in addition to the usual antenna design requirements, also interference phenomena arising from the integration of different classes of antennas in a compact device. In this framework, the paper describes a methodology based on a stochastic multiphases optimization approach for the design of an integrated multifunction/multiband antenna system. Moreover, for an exhaustive assessment, the results of an experimental validation performed on a prototype of the multifunction antenna system are shown and discussed. [ABSTRACT FROM PUBLISHER]

Considers the relation between the measured voltage and the unperturbed electric field at the probe position, which is the starting point for the development of measurement systems based on the modulated scattering technique (MST). Arrangements for the MST; Bistatic MST relationship.