Juan Vicente Balbastre-Tejedor

On the application of singular value decomposition and Tikhonov regularization to ill-posed problems in hyperbolic passive location

Abstract Hyperbolic passive location of targets (e.g. used in the Multilateration systems for civil aviation) calls for the solution of highly non-linear systems. In this paper, we show how the effect of typical ill-conditioning of passive location, arising in many operational conditions, may be significantly mitigated by regularization techniques. The pertaining advantages with respect to the conventional (non-regularized) approach are shown in a realistic situation.

Resonance suppression in enclosures with a metallic-lossy dielectric layer by means of genetic algorithms

Conductive plastics have become an alternative to traditional metallic cabinets to shield boxes from electromagnetic interferences. These materials allow a wide range of conductivities that can satisfy any particular design. A design with an outer metallic layer and an inner layer of conductive dielectric can obtain advantages from both materials. In this paper the damping of resonances in enclosures with an aperture through conductive dielectrics is optimized by means of Genetic Algorithms with the aid of a three dimensional simulation tool. Genetic Algorithms are a general purpose optimization technique widely used in the last years for electromagnetic design. The relationship between obtained solutions and skin depth parameter is shown in order to help in design procedures.

Efficient location strategy for airport surveillance using mode-s multilateration systems

In this paper, the use of regularization methods to solve the location problem in multilateration systems, using Mode-S signals, is studied, evaluated, and developed. The Tikhonov method has been implemented as a first application to solve the classical system of hyperbolic equations in multilateration systems. Some simulations are obtained and the results are compared with those obtained by the well-established Taylor linearization and with the CramA©r-Rao lower bound analysis. Significant improvements, for the accuracy, convergence, and the probability of location, are found for the application of the Tikhonov method. © Cambridge University Press and the European Microwave Association, 2012.

An Ant Colony Optimization Algorithm for Microwave Corrugated Filters Design

A practical and useful application of the Ant Colony Optimization (ACO) method for microwave corrugated filter design is shown. The classical, general purpose ACO method is adapted to deal with the microwave filter design problem. The design strategy used in this paper is an iterative procedure based on the use of an optimization method along with an electromagnetic simulator. The designs of high-pass and band-pass microwave rectangular waveguide filters working in the C-band and X-band, respectively, for communication applications, are shown. The average convergence performance of the ACO method is characterized by means of Monte Carlo simulations and compared with that obtained with the well-known Genetic Algorithm (GA). The overall performance, for the simulations presented herein, of the ACO is found to be better than that of the GA.

Selection and adjustment of propagation models to compute the electric field strength for exposure assessment purposes in urban environment

This work deals with the selection of the best suited propagation models for computing electric field strength for exposure level assessment in urban environments in Colombia. The selection is based on the comparison of numerical results obtained using a well known commercial tool and measurements performed in the bands assigned in Colombia to the Digital Television Broadcasting (470 MHz-698 MHz) and Digital Radio Trunking (806 MHz-898 MHz).

An effective procedure to design the layout of standard and enhanced mode-S multilateration systems for airport surveillance

In this paper, an effective procedure to emplace standard and enhanced mode-S multilateration stations for airport surveillance is studied and developed. This procedure is based on meta-heuristic optimization techniques, such as genetic algorithm (GA), and is intended to obtain useful parameters for an optimal system configuration that provides acceptable performance levels. Furthermore, the procedure developed here is able to evaluate and improve previous system designs, as well as possible system enhancements. Additionally, the design strategies to be used along with the procedure proposed here are fully described. Parameters such as the number of stations, the system geometry, the kind of measurements to be used, and the system accuracy are obtained taking into account the basic requirements such as the Line of Sight, the probability of detection, and the accuracy levels. © Cambridge University Press and the European Microwave Association, 2012.

Electromagnetic Interference Reduction in Electronic Systems Cabinets by Means of Genetic Algorithms Design

Conductive plastics have become an alternative to traditional metallic cabinets to shield boxes from electromagnetic interferences. The wide range of available conductivities with these materials can satisfy any particular design. A design with an outer metallic layer and an inner layer of conductive dielectric can obtain advantages from both materials. In this paper the design by means of genetic algorithms of electronic systems cabinets made of new plastic materials to reduce electromagnetic radiated interferences in enclosures with an aperture is described. This optimization procedure requires the use of electromagnetic simulators with a high computational cost. A 2D simulation tool is used in this work for evaluating 3D structures, reducing drastically the computation time. The relationship between obtained solutions and skin depth parameter is evaluated to help in design procedures. A commercial 3D full wave electromagnetic tool has been used to validate the obtained results.