183 research outputs found
Perspectives of the european academic research in the microwave..
Peer ReviewedPostprint (published version
Condiciones de existencia de modos de orden superior en estructuras planares
Conditions for existence of higher-order modes of the reduced wave equation V2 u + Au = 0 on semi - infinite domains subjected to different boundary conditions are presented and applied to the slot line. Bounds for the lowest eigenvalues are obtained using the Method of Moments.Peer ReviewedPostprint (published version
RCS of engine inlets by a spectral iterative technique
A novel algorithm designed to compute efficiently and accurately the HF electromagnetic scattering from open-ended waveguide cavities is presented. The cavity is converted into a stepped-waveguide model so that the field spectrums are propagated, forward and backward, along each waveguide section. As boundary conditions for perfect electric conductors are applied via image theory, they are of local nature and take into account only the first order interactions between each pair of waveguide sections. Accordingly, additional forward-backward iterations must be performed if multiple interactions are to be taken into account. Finally, the RCS due to the interior irradiation is calculated by a Kirchhoff-based aperture integral. Good agreement with Method of Moments and Hybrid Modal solutions is found, as well as with experimental data, for 2-D and 3-D cavities.Peer ReviewedPostprint (published version
Modal analysis of coupling problems in optical fibers
Peer ReviewedPostprint (published version
Bidimensional scattering of tm and te polarized waves by dielectric
In the study of electromagnetic radiation effects over dielectric bodies, effective numerical methods are needed. At present, there is a lack of tools for measuring this effects and due to the huge growth of microwave devices, like cellular radio telephones working close to the human body, it is necessary to develop accurate numerical methods for evaluating those effects. One of the most efficient and extensively used method is the FFT-CGM (Fast-Fourier-Transform Conjugate Gradient Method). In this paper, algorithms for solving the two-dimensional scattering of transversal magnetic (TM) and transversal electric (TE) polarized waves by a lossy dielectric and metallic objects are presented. At the same time, the SAR (Specific Absorption Rate) of tissues and the modified radiation diagrams when the body is present are obtained from the diffracted fields.Peer ReviewedPostprint (published version
Caracterización electromagnética de materiales RAM mediante medidas en espacio libre
A free-space measurement system in the 2-JBGHz frequency range is used to measure the reflection and transmission coefficients of planar samples. The complex electric permittivity and the magnetic permeability are calculated from the measured values of S11 and S21. The measurement system consists of broadband transmit and receive antennas, a network analyzer, mode transitions, and a computer. Error due to multiple reflections between antennas via the swjace of the sample are corrected by using a free space T.R.L. calibration technique.Peer ReviewedPostprint (published version
Caracterisation d'un systeme experimental pour la mesure a champ proche
Pendant les dernières années on a suscité un fort intérêt pour la mesure de la distribution des champs dans la zone proche des ouvertures, ainsi que pour son utilisation dans l'obtention des caractéristiques de rayonnement et la restitution de la répartition d'amplitude et phase sur l'ouverture même de l'antenne.
On présente d'abord un système complet d'acquisition, traitement et représentation des mesures en champ proche. On présente aussi une étude des différents paramètres qui interviennent : longueur de la mesure, pas d'échantillonnage et distance sonde ouverture, ainsi qu'une étude de l'influence produite par la sonde et les algorithmes de correction.Peer ReviewedPostprint (published version
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