Spline-shaped ultra-wideband antenna operating in the ECC released frequency spectrum

A spline-shaped antenna for Ultra-Wideband (UWB) communications that operates in the Electronic Communications Committee (ECC) released band from 6 GHz up to 8.5 GHz is described. Selected simulated and measured data are reported to assess the achieved impedance matching over the whole band of interest, and the distortionless behavior as well as to show the omnidirectional radiation properties. This paper is a postprint of a paper submitted to and accepted for publication in Electronics Letters and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital Library

Synthesis of a Galile oand 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. (c) 2007 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works

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

This report presents the result of the synthesis of an horizontally polarized reconfigurable microstrip antenna

A SVM-Based Multi-Resolution Procedure for the Estimation of the DOAS of Interfering Signals in a Communication System

In this work, the use of a planar antenna system for the estimation of the directions of arrivals (DOAs) of multiple signals impinging on the receiver has been considered. Towards this end, an efficient multi-resolution method based on a SVM-classifier is proposed for determining a probabilitic map of the DOAs of the unknown interfering signals. Numerical results dealing with multiple interferers scenarios in noisy environments are provided in order to assess the feasibility as well as the capability of the proposed approach

Experimental validation of a fully-adaptive smart antenna prototype

The architecture of a fully-adaptive smart antenna working in the 2.4 GHz band is described and its functionalities preliminarily assessed. The radiating unity consists of an eight-element linear array of dipoles with a finite reflecting plane. The adaptive behaviour is achieved by means of a set of electronically-driven vector modulators that realise the array weights. The capability to react in real-time to complex interference scenarios is provided by an SW control module based on the particle swarm optimiser (PSO) algorithm. To assess the effectiveness of such an implementation, a selected set of results is reported and discussed. This paper is a postprint of a paper submitted to and accepted for publication in Electronics Letters and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital Library

Ray propagation in nonuniform random lattices,”

In this paper and its companion [J. Opt. Soc. Am. A. 23, 2251 (2006)], the problem of ray propagation in nonuniform random half-plane lattices is considered. Cells can be independently occupied according to a density profile that depends on the lattice depth. An electromagnetic source external to the lattice radiates a monochromatic plane wave that undergoes specular reflections on the occupied sites. The probability of penetrating up to level k inside the lattice is analytically evaluated using two different approaches, the former applying the theory of Markov chains (Markov approach) and the latter using the theory of Martingale random processes (Martingale approach). The full theory concerned with the Martingale approach is presented here, along with an innovative modification that leads to some improved results. Numerical validation shows that it outperforms the Markov approach when dealing with ray propagation in dense lattices described by a slowly varying density profile

Innovative Design of a Planar Fractal-Shaped GPS/GSM/Wi-Fi Antenna

In this letter, the design of a microstrip three-band antenna working in GPS, GSM and Wi-Fi frequency bands is described. By considering a planar geometry printed on a dielectric substrate, the tuning of the antenna behavior in three non-harmonic frequency bands is obtained perturbing the patch perimeter according to a Koch-like fractal shape. The synthesis procedure is automatically performed by means of an iterative PSO-based optimization strategy where a fractal boundary generator is integrated with a MoM-based electromagnetic simulator. The feasibility of the approach as well as the reliability of the synthesized antenna is assessed through simulations as well as experimental results. The definitive version is available at www3.interscience.wiley.co

Determination of the complex permittivity values of planar dielectric substrates by means of a multifrequency PSO-based technique

In this paper, an innovative technique for the determination of the dielectric properties of planar substrates is presented. Starting from a set of impedance measurements performed on a section of a microstrip transmission line built on the planar dielectric substrate under test, the proposed technique formulates the reconstruction problem in terms of an optimization one successively solved by means of an effective stochastic algorithm. Such a method allows one the reconstruction of the permittivity values at multiple frequencies by simply using a vector network analyzer and a standard calibration procedure for the impedance measurement. The results of some representative experimental tests are shown for a preliminary assessment of the effectiveness of the proposed approach. (c) The Electromagnetics Academy - The final version of this article is available at the url of the journal PIER M: http://www.jpier.org/PIERM/pier.php?paper=0911290

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

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 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

A Miniaturization Process of an Antenna With Pre-Fractal Geometry by Means of a Particle Swarm Optimization

This work presents a synthesis procedure for designing miniaturized pre-fractal antennas for wireless applications. In order to minimize the linear dimensions of the antenna and to obtain Voltage Standing Wave Ratio values within specifications, the device configuration has been synthesized by defining a suitable building pre- fractal geometry tuned through a customized Particle Swarm Optimizer. This is the author's version of the final version available at IEEE