This letter presents the design of a planar antenna for ultrawideband (UWB) applications with a bandwidth of 5.5 GHz over 3.7 to 9.2 GHz and return loss values lower than -10 dB. The antenna geometry is described in terms of a spline-based representation whose control parameters, together with other geometrical descriptive quantities, are determined through a suitable particle swarm optimizer (PSO) in order to fit the UWB requirements. Representative results of both numerical and experimental validations are reported in order to assess the performance of the prototype as well as to give some preliminary indications on the reliability and effectiveness of the whole synthesis approach

This letter presents the result of the synthesis of a horizontally polarized reconfigurable microstrip antenna. The obtained architecture is based on a parasitic structure composed by a set of microstrip elements that can be electronically reconfigured by means of radiofrequency (RF) switches. As a result, the maximum values and zeros of the antenna radiation pattern can be steered towards an interfering signal or/and desired signals, which allows an optimal management of wireless resources. Representative numerical and experimental results are reported and compared in order to assess the effectiveness and reliability of the proposed prototype.

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.

In this paper, a hybrid approach for the synthesis of the ldquooptimalrdquo 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.

In the framework of control methods for adaptive phased-arrays, this paper deals with complex communication scenarios by considering a memory-enhanced cooperative algorithm. Compared to existing approaches where far-field interferences are taken into account, the proposed analysis considers a more realistic situation where the jamming sources are located either in the near-field or in the far-field of the receiving antenna. In order to carefully address the arising challenges and to effectively deal with such complex environments, an optimization approach based on an enhanced particle swarm optimizer (PSO)-based algorithm is used. The obtained results seem to confirm the effectiveness of the proposed technique in terms of both signal-to-noise ratio and computational costs and complexity.

This paper is aimed at proposing a multiband fractal antenna suitable for wireless communication systems devoted to emergency management. The synthesis of the antenna is carried out by means of an ...