Renzo Azaro

Optimization of a Spline-Shaped UWB Antenna by PSO

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

A Planar Electronically Reconfigurable Wi-Fi Band Antenna Based on a Parasitic Microstrip Structure

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.

Memory Enhanced PSO-Based Optimization Approach for Smart Antennas Control in Complex Interference Scenarios

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.

PSO-Based Real-Time Control of Planar Uniform Circular Arrays

This letter is aimed at assessing the effectiveness of the phase-only control strategy based on a customized PSO when applied to planar uniform circular arrays (PUCA) and in the presence of interferences both in the near-field and far-field of the antenna. The employed geometry seems to be suitable for a reliable and effective implementation of adaptive arrays in mobile devices thanks to its symmetry and geometric simplicity. For validation purposes, the proposed architecture is evaluated in the presence of a complex time-varying scenario both in terms of synthesized beam patterns and signal-to-interference-plus-noise ratio

An innovative computational approach based on a particle swarm strategy for adaptive phased-arrays control

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

A Miniaturized UWB Antenna for Wireless Dongle Devices

In this letter, a planar ultra wideband (UWB) antenna suitable for the integration in wireless universal serial bus (USB) dongles is described. The antenna has a bandwidth equal to 2 GHz from 3 GHz up to 5 GHz with return loss values below -10 dB in the whole frequency range. To comply with UWB system needs, the antenna presents good distortionless properties when employed in a TX/RX system. Moreover, thanks to its simple shape and miniaturized geometry, the proposed prototype can be easily integrated and printed on dongle PCBs. In order to assess the reliability and efficiency of the antenna, a selected set of results from the experimental validation are shown and compared with the outcomes of the numerical simulations carried out during the synthesis process.

A PSO-Driven Spline-Based Shaping Approach for Ultrawideband (UWB) Antenna Synthesis

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.

A Hybrid Prefractal Three-Band Antenna for Multistandard Mobile Wireless Applications

In this letter, the synthesis of a miniaturized three-band planar antenna working in GSM and WiFi frequency bands is described. The reference geometry for the synthesis of the antenna is a hybrid prefractal shape obtained by integrating a Sierpinski-like and a Meander-like structure. The synthesis of the geometrical parameters of the antenna has been performed by means of a customized particle swarm strategy to yield electrical parameters within given specifications. In order to show the effectiveness of the approach, some results from the numerical synthesis procedure are described and a comparison between simulations and experimental measurements is reported.

A Monopolar Quad-Band Antenna Based on a Hilbert Self-Affine Prefractal Geometry

In this letter, the design of a quad-band antenna is presented. The antenna has a planar geometry printed on a dielectric substrate orthogonal to a reference ground plane and its geometrical parameters are optimized starting from a Hilbert-like prefractal reference shape. The reliability of the synthesized antenna is assessed by means of a set of experimental tests to verify its compliance with the project constraints.

Synthesis of a Galileo and Wi-Max Three-Band Fractal-Eroded Patch Antenna

In this letter, the synthesis of a three-band patch antenna working in E5-L1 Galileo and Wi-Max frequency bands is described. The geometry of the antenna is defined by performing a Koch-like erosion in a classical rectangular patch structure according to a Particle Swarm strategy to optimize the values of the electrical parameters within given specifications. In order to assess the effectiveness of the antenna design, some results from the numerical synthesis procedure are described and a comparison between simulations and experimental measurements is reported.