Arbitrary wave synthesis using spectral transformations

The different transformations among plane, cylindrical and spherical spectrum allow to tackle the arbitrary field synthesis from a set of known sources. Putting all the spectrums in the same coordinate axis we can obtain a system of equations that allows us to find the optimal source weights, which synthesize the wished field. In this paper we present how to get the minimum number of sources needed to obtain a plane wave that allows to measure antennas or radar cross section in an indoor near-fleld range.Peer ReviewedPostprint (published version

Multimode equivalent network representation for multiple arbitrarily shaped posts in H-plane waveguide

This paper presents a method for the calculation of the S-parameter of arbitrary shape and composition post or group of posts in a waveguide. The method segments the problem into regions that are characterized by their respective generalized admittance matrix (GAM). Analytic formulation as well as a boundary integral formulation based on the wave function are used in this characterization. Our method is specially suitable for its incorporation in real time CAD tools because only the changing parameters must be computed. This method also permits the simple combination of different numerical techniques.Peer ReviewedPostprint (published version

Circuital analysis of a two-port angular sector

The authors introduce an element that allows them to analyze two-dimensional diffraction problems in a circuital way. The circuital analysis of electromagnetic problems, together to the segmentation technique, allows one to analyse large problems, in an electromagnetic sense, with the additional advantage that a change in a material is readily computed. This makes this method very appropriate for its use in CAD tools. The problem of a sector considered as a quadripole is only presented, in such a way that we can set the advantages of the method. It is easy to see how we can enlarge the problem to a four-port net. Finally, we must say that only the TM case is presented.Peer ReviewedPostprint (published version

Propagation modes in lossy cylindrical structures

The purpose of this communication is to calculate the orders of the Bessel functions that satisfies the equation f/sub v/(r)=J/sub v/(k/sub r//spl middot/r)+A/sub v//spl middot/Y/sub v/(k/sub r//spl middot/r) when the contour conditions are f/sub v/(a)=f/sub v/(b)=0. We will see that when k/sub r/ is a constant then the orders v may be complex.Peer ReviewedPostprint (published version

Medidas de propagación sobre el mar a 900 MHz

In this article, propagation measurements over the sea in 900 MHz band are presented. Objective of these measurements is to have a set of real data for the study of radiowave propagation over the sea in this band.Peer ReviewedPostprint (published version

A comparison of phase unwrapping techniques in synthetic aperture radar interferometry

A comparison of different phase unwrapping techniques based on the least mean square error is presented. A testing environment based on simulated interferograms has been created in order to assess the methods described in the literature. Each of them has shown good properties under different constraints. Multigrid with a previous adaptive maximum likelihood gradient estimation is very robust when strong aliasing is not expected. In a general scenario with aliasing, an adaptive multiresolution gradient estimator gives a coarse approximation to the low resolution topography.Peer ReviewedPostprint (published version

Full-wave equivalent network representation for multiple arbitrarily shaped posts in H-plane waveguide

This paper presents a method for the analysis of arbitrary shape and composition posts in a waveguide. The method segments the problem into regions that are characterized by their generalized admittance matrices. Both an analytical formulation and a boundary integral formulation based on homogeneous wave equation solutions are used in this characterization. Our method is especially fast and suitable for real time computer-aided design tools because only the changing parameters would have to be computed in a design process. This method also makes a simple combination of different numerical techniques possible.Peer ReviewedPostprint (published version

Analysis of inhomogeneous and anisotropic waveguides by the finite element method

Two numerically efficient procedures for the analysis of arbitrarily-shaped inhomogeneous and anisotropic waveguides showing no spurious modes are considered. The first is based on a transverse magnetic-field formulation, while the second is straightforwardly derived from the first-order Maxwell curl equations and involves all the components of the electric and magnetic fields. In both cases, the final step, in most cases, to solve a symmetric complex generalized eigensystem. An extension of the symmetric real case to the symmetric complex case is developed in order to reduce the time consumed in the solution process.Peer ReviewedPostprint (published version

A new hybrid mode-matching method for the analysis of inductive obstacles and discontinuities

A new and efficient hybrid mode-matching method for the analysis of arbitrarily shaped inductive obstacles and discontinuities is presented. An open-space spectral method is used to model the electrical behavior of the inductive problem, and the mode-matching technique is then employed for obtaining a multimode scattering matrix representation. This new method is revealed very useful for the accurate and efficient analysis of inductive problems including very arbitrary geometries. Results for some classical inductive problems covered in the literature are shown, thus confirming the accuracy of the results provided by the new technique.Peer ReviewedPostprint (published version

Analysis of multireflector antenna clusters by spectral methods

This paper analyzes multireflector antennas making use of spectral domain techniques. The behaviour of the multireflector antenna is determined by means of a transference function that relates the plane wave spectrum of an incident signal on this antenna to the plane wave spectrum reflected by the structure. Multireflector antenna clusters that synthesize specific radiation patterns have also been undertaken. The paper allows us to generalize the identification of every reflecting object through a transference function that relates the incident spectrum to the reflected one. This will permit us to analyze reflection problems with multiple structures.Peer ReviewedPostprint (published version