Stefano Selleri - Profile on Academia.edu (original) (raw)

Papers by Stefano Selleri

Electronics Letters, Jul 1, 2018

A method to reduce the mutual coupling in wide-band multilayer patch array operating in C band is... more A method to reduce the mutual coupling in wide-band multilayer patch array operating in C band is presented. The proposed device use conveniently sized meander line parasites printed on the same substrate of the upper patch. Measurements on a 2 × 2 prototype shows a measured bandwidth of about 19.6% centred at 5.1 GHz, therefore adequate to cover the whole WLAN frequency range. The meander lines allow to reduce the patch mutual coupling by about 2.4 dB.

Point source estimation consists of detecting and localizing a concentrated diffusive source as w... more Point source estimation consists of detecting and localizing a concentrated diffusive source as well as estimating its intensity and induced field from pointwise-in-time-and-space measurements of sensors deployed over the area of interest. The spatiotemporal dynamics of the diffused field is modeled by a partial differential equation (PDE) and a finite element (FE) method is employed for spatially discretizing the PDE model. Source identifiability, i.e. the possibility of detecting the source and uniquely identifying its location and intensity, is analysed in a system-theoretic framework. Further, a novel multiple model filtering approach to source estimation is presented and its effectiveness is demonstrated via a simulation experiment.

2019 6th IEEE History of Electrotechnology Conference (HISTELCON)

The International System of units used nowadays in most of the word experienced a turning point i... more The International System of units used nowadays in most of the word experienced a turning point in the first half of the XX century with the introduction of the ampere (A) as a fourth unit in addition to the original length (M -meter), mass (K -kilogram) and time (S -second), hence turning from a MKS to a MKSA system. This addition was a non-trivial and lengthy process mainly carried on by the Italian engineer Giovanni Giorgi. This contribution retraces this revolution in the measurement system.

Progress in Electromagnetics Research C, Dec 31, 2022

A three-way power divider based on Bagley polygon is here reduced in dimension by applying the co... more A three-way power divider based on Bagley polygon is here reduced in dimension by applying the concept of reducing delay line length by applying open circuit stubs. Whereas this technique is known in literature, the delay line reduction is done symmetrically by placing the stub mid-line, which would imply packing issues leading to a reduced size reduction. In this contribution a theoretical development on non-symmetric reduced length delay line is carried out, allowing for a more effective size reduction of the Bagley-based power divider. Measurements on a prototype designed at 2.45 GHz occupying less than half of the area of a canonical Bagley divider with comparable performances over a slightly reduced operational bandwidth prove the validity of the approach.

Contents Radio Science Bulletin Staff .

arXiv (Cornell University), Apr 8, 2016

The paper deals with decentralized state estimation for spatially distributed systems described b... more The paper deals with decentralized state estimation for spatially distributed systems described by linear partial differential equations from discrete in-space-and-time noisy measurements provided by sensors deployed over the spatial domain of interest. A fully scalable approach is pursued by decomposing the domain into overlapping subdomains assigned to different processing nodes interconnected to form a network. Each node runs a local finitedimensional Kalman filter which exploits the finite element approach for spatial discretization and the parallel Schwarz method to iteratively enforce consensus on the estimates and covariances over the boundaries of adjacent subdomains. Stability of the proposed distributed consensus-based finite element Kalman filter is mathematically proved and its effectiveness is demonstrated via simulation experiments concerning the estimation of a bi-dimensional temperature field. Index Terms Networked state estimation; distributed-parameter systems; finite element method; Kalman filtering; consensus. I. INTRODUCTION T HE recent breakthrough of wireless sensor network technology has made possible to cost-effectively monitor spatially distributed systems via deployment of multiple sensors over the area of interest. This clearly paves the way for several important practical monitoring applications concerning, e.g., weather forecasting [1], water flow regulation [2], fire detection, diffusion of pollutants [3], smart grids [4], vehicular traffic [5]. The problem of fusing data from different sensors can be accomplished either in a centralized way, i.e. when there is a single fusion center collecting data from all sensors and taking care of the overall spatial domain of interest, or in distributed (decentralized) fashion with multiple intercommunicating fusion centers (nodes) each of which can only access part of the sensor data and take care of a sub-region of the overall domain. The decentralized approach is preferable in terms of scalability of computation with the problem size and will be, therefore, undertaken in this paper. Since spatially distributed processes are usually modeled as infinite-dimensional systems, governed by partial differential equations (PDEs), distributed state estimation for such systems turns out to be a key issue to be addressed. While a lot of work has dealt with distributed consensus-type filters for finite-dimensional, both linear [6]-[9] and nonlinear [10], systems as well as for multitarget tracking [11], considerably less attention has been devoted to the more difficult case of distributed-parameter systems. Recent work [12]-[16] has addressed the design of distributed state estimators/observers for large-scale systems formed by the sparse interconnection of many subsystems (compartments). Such systems are possibly (but not necessarily) originated from spatial discretization of PDEs. In particular, [12] presents a fully scalable distributed Kalman filter based on a suitable spatial decomposition of a complex large-scale system as well as on appropriate observation fusion techniques among the local Kalman filters. In [13], non-scalable consensus-based multi-agent estimators are proposed wherein each agent aims to estimate the state of the whole large-scale system. In [14], a moving-horizon partition-based approach is followed in order to estimate the state of a large-scale interconnected system and decentralization is achieved via suitable approximations of covariances. Further, [15] deals with dynamic field estimation by wireless sensor networks with special emphasis on sensor scheduling for trading off communication/energy efficiency versus estimation performance. In [16], design of distributed continuous-time observers for partitioned linear systems is addressed.

Improved Particle Swarm Optimization algorithms for electromagnetic optimization

Soft Computing, 2008

Improved Particle Swarm Optimization Algorithms for Electromagnetic Optimization

A comparison between basis functions for the efficient invasive weed optimization‐based optimization of phase‐only linear array patterns

Microwave and Optical Technology Letters

Synthesis of phased array antennas generating shaped patterns by exploiting phase tapering only i... more Synthesis of phased array antennas generating shaped patterns by exploiting phase tapering only is a challenging problem. A phase‐only tapering permits maximizing the DC to RF power efficiency and results to be particularly useful in satellite applications with stringent constraints on the available power. Such a synthesis is a highly nonlinear problem most effectively addressed via stochastic optimization techniques. In this paper several basis functions to represent the phase distribution are traded‐off and compared, within an invasive weed optimization paradigm.

IEEE Transactions on Antennas and Propagation, 2022

HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

URSI Radio Science Bulletin, 2017

Excitation amplitudes tolerance analysis for linear arrays with phase-only tapering

2021 XXXIVth General Assembly and Scientific Symposium of the International Union of Radio Science (URSI GASS), 2021

A study on the dispersion in the values of amplification within a linear phased arrays is present... more A study on the dispersion in the values of amplification within a linear phased arrays is presented. In a phase-only array in which the phase distribution is optimized the amplitudes of each radiating element should be the same. Indeed real world amplifiers have a dispersion in their parameters leading to variable amplification factors. In this paper a Monte Carlo statistic analysis on how this variability reflects in the radiation pattern is be analyzed.

2019 URSI Asia-Pacific Radio Science Conference (AP-RASC), 2019

A variation on the conventional sinuous antenna design, in its slot version, is proposed, to achi... more A variation on the conventional sinuous antenna design, in its slot version, is proposed, to achieve a higher degree of linear polarization purity. The antenna is designed for the UWB frequency band the 3.1-10.6 GHz band. Simulated results shows the high degree of polarization purity attained.

─ In this paper, a wide band monopole antenna with a shaped profile is presented. Shaped profile ... more ─ In this paper, a wide band monopole antenna with a shaped profile is presented. Shaped profile and end-caps allow for a compact antenna with respect to wavelength. Antenna is designed to be as isotropic as possible and with low phase deviation from spherical wave front to allow accurate detection of the direction of arrival of an unknown signal when used in radiogoniometry applications. Index Terms ─ Antennas, shaped monopole, radiogoniometry, wide-band antennas.

Proceedings e report, 2016

When Courant prepared the text of his 1942 address to the American Mathematical Society for publi... more When Courant prepared the text of his 1942 address to the American Mathematical Society for publication, he added a two-page Appendix to illustrate how the variational methods first described by Lord Rayleigh could be put to wider use in potential theory. Choosing piecewise-linear approximants on a set of triangles which he called elements, he dashed off a couple of two-dimensional examples and the finite element method was born. … Finite element activity in electrical engineering began in earnest about 1968-1969. A paper on waveguide analysis was published in Alta Frequenza in early 1969, giving the details of a finite element formulation of the classical hollow waveguide problem. It was followed by a rapid succession of papers on magnetic fields in saturable materials, dielectric loaded waveguides, and other well-known boundary value problems of electromagnetics. … In the decade of the eighties, finite element methods spread quickly. In several technical areas, they assumed a domi...

Physical Review B, 2019

Feasibility of Topological Metawaveguides supporting helical propagation in the microwave range h... more Feasibility of Topological Metawaveguides supporting helical propagation in the microwave range has been recently proven. The advantages of unidirectional propagation supported by such waveguides however can only be exploited in real devices if topological modes are endowed with the capability to interact within themselves as well as with trivial modes. Here we show a modal launcher to interface a topological metawaveguide with conventional circular waveguides with negligible reflection and we exploit the properties of coupled topological modes to show a proof of concept of a topological contra-directional coupler.

Physics Education, 2013

Catt's anomaly is a sort of 'thought experiment' (a gedankenexperiment) where electrons seem to t... more Catt's anomaly is a sort of 'thought experiment' (a gedankenexperiment) where electrons seem to travel at the speed of light. Although its author argued with conviction for many years, it has a clear and satisfactory solution and it can be considered indubitably just an apparent paradox. Nevertheless, it is curious and very intriguing, and able to capture the attention of students.

Progress In Electromagnetics Research, 2018

Polyomino-based arrays allow to efficiently exploit the available array area with a regular eleme... more Polyomino-based arrays allow to efficiently exploit the available array area with a regular element lattice, yet exhibit a nonuniform distribution of their phase centers, leading to superior electronic scanning capabilities. Yet polyomino arrays are usually implemented via polyomino of equal order, leading to uniform amplitude distribution and poor side lobe levels. In this contribution, a tiling of polyominoes of different orders is proposed to attain at the same time good scanning characteristics and side lobe level.

2020 XXXIIIrd General Assembly and Scientific Symposium of the International Union of Radio Science

In this work it is proposed the design of a couple of UWB two-arm sinuous antennas working in 2-1... more In this work it is proposed the design of a couple of UWB two-arm sinuous antennas working in 2-18 GHz (Antenna A) and 6-18 GHz (Antenna B) frequency bands assembled in a ultra-wideband array for direction finding applications. Both antennas work with a slant 45° polarization ensuring good matching impedance and stable radiation characteristics in the considered frequency bands. The design has been optimized in order to reduce the geometrical dimensions. The proposed antennas have been manufactured and tested in order to validate the simulation performances. Finally the evaluation of accuracy performances in estimating the direction of arrival of an incoming wave-front is presented.

Progress In Electromagnetics Research Letters

A single-layer via-less rectangular patch antenna for automotive applications in C-band is propos... more A single-layer via-less rectangular patch antenna for automotive applications in C-band is proposed. To match the needs of a vehicular dedicated short range communication protocol, the resonant edge of the antenna is enlarged to narrow the beamwidth in the H-plane, while at the same time a pair of thin slots serve as inhibitors for the higher modes, permitting adequate matching and polarization purity. The proposed single patch antenna presents a realized gain about 6.85 dB, H-plane beamwidth narrower than ±32 • , E-plane beamwidth larger than ±45.5 • , and return loss exceeding 20 dB with a 3 dB bandwidth of 500 MHz, with a minimum at 5810 MHz, hence suitable for coexistence of different communication standard in the C-band. Furthermore, its compact dimension permits the direct integration within a radio front-end.