F. Saez de Adana

Efficient ray-tracing techniques for three-dimensional analyses of propagation in mobile communications: application to picocell and microcell scenarios

The application of several ray-tracing techniques, in combination with GTD/UTD (geometrical theory of diffraction/uniform theory of diffraction), for an efficient analysis of propagation in urban scenarios is presented. The frequency of the analysis is in the UHF band, and a three-dimensional model of the geometry, using flat facets, is considered. After a review of the most commonly used ray-tracing techniques, a new method, called the angular z-buffer (AZB) technique, is presented. As is shown and validated with results, the AZB appears to be extremely efficient for GTD/UTD applications.

THE APPLICATION OF RAY-TRACING TO MOBILE LOCALIZATION USING THE DIRECTION OF ARRIVAL AND RECEIVED SIGNAL STRENGTH IN MULTIPATH INDOOR ENVIRONMENTS

This work presents a new indoor localization method based on the fingerprinting technique. The proposed method uses a ray-tracing model that provides information about multipath effects. This information is stored in a dataset during the first stage of the fingerprinting method. The direction of arrival (DOA) and received signal strength (RSS) are used in the fingerprinting technique as a hybrid system. The localization estimation is calculated while taking into account the Euclidian distance between the DOA and the RSS from each unknown position and the information of the fingerprints. Numerical calculations were performed to show the mean and the standard deviation of the estimated error.

FASANT: past computer tool for the analysis of on-board antennas

FASANT is a computer tool for the analysis of antennas on-board satellites, ships, aircraft, and other complex bodies. The structure under analysis, which can be metallic or dielectric (with and/or without losses), must be modeled by plane and/or curved surfaces. The geometrical input files are in DXF format, and can be generated by the most commonly used computer-aided geometrical-design (CAGD) tools. The code can also be applied to the analysis of arrays and arbitrarily shaped reflectors. The kernel of the code is based on the uniform theory of diffraction (UTD). Special algorithms have been developed to speed up the ray-tracing computation for both flat and curved surfaces. FASANT can obtain far-field patterns, field levels at points near the structure, can calculate the mutual coupling between antennas or between array elements, and can show each ray-tracing mechanism.

Indoor 3D Full Polarimetric Bistatic Spherical Facility for Electromagnetic Tests

A new indoor facility for electromagnetic measurements has been developed and built at the Detectability and Electronic Warfare Laboratory, INTA, Spain. The system was designed to extend the previous capabilities so that not only monostatic but also bistatic radar cross section (RCS) tests could be easily conducted. Due to limited space, far-field radar cross sections in the system are restricted to small targets, but this layout will allow the researchers to investigate ReS near-field-to-far-field transformations. The system was also conceived to be versatile enough to carry out other tests, such as near-field antenna measurements, material-absorption measurements, and electromagnetic characterization of materials. The paper describes the novel concept behind the facility, and presents some preliminary measurement results on different applications.

New version of FASANT code

This paper presents an overview of the new FASANT code based on a combination of the uniform theory of diffraction (UTD) and physical optics (PO). This code is a powerful tool to analyze the radiation pattern of antennas on board in complex structures in an easy way. The structures must be electrically large and can be modeled by flat and/or curved surfaces defined by perfect electrical conductors or dielectric materials. This code has been validated using several complex test cases, showing good agreement between simulations and measurements.

A novel hybrid FEM high-frequency technique for the analysis of scattering and radiation problems

A novel hybrid Finite Element Method and High Frequency Technique for the efficient analysis of scattering and radiation problems is presented. Results of the analysis of two-dimensional scattering and radiation problems using Physical Optics as the high frequency technique are given showing some of the features of the method.

Efficient Time-Domain Ray-Tracing Technique for the Analysis of Ultra-Wideband Indoor Environments including Lossy Materials and Multiple Effects

This paper presents an efficient application of the Time-Domain Uniform Theory of Diffraction (TD-UTD) for the analysis of Ultra-Wideband (UWB) mobile communications for indoor environments. The classical TD-UTD formulation is modified to include the contribution of lossy materials and multiple-ray interactions with the environment. The electromagnetic analysis is combined with a ray-tracing acceleration technique to treat realistic and complex environments. The validity of this method is tested with measurements performed inside the Polytechnic building of the University of Alcala and shows good performance of the model for the analysis of UWB propagation.

Evaluation of Particle Swarm Optimization Applied to Single Snapshot Direction of Arrival Estimation

A heuristic solver such as particle swarm optimization (PSO) is used for single snapshot direction of arrival (DOA) estimation of a set of signals impinging on a uniform linear array (ULA). A performance analysis for infinite signal-to-noise ratio (SNR) shows the validity of this approach and an example using signal and ULA parameters from a more realistic DOA problem is also included.

Ray-tracing acceleration techniques to compute RCS of complex targets

A combination of acceleration techniques to compute the RCS (radar cross section) of complex targets is presented. The approach is based on the application of the angular Z-buffer (AZB) algorithm together with the SVP (space volumetric partitioning) algorithm, for electrically large and complex bodies modeled by a high number of flat and/or curved surfaces.

Comparison of empirical models and deterministic models for the analysis of interference in indoor environments

In this paper, two different models for indoor electromagnetic interference prediction are compared: one empirical and another deterministic based on ray-tracing. Results for two different scenarios have been obtained, one corridor and one office building. Results demonstrate that both methods predict similar path lost. The main difference between these methods is that empirical one cannot predict local maximum and minimum due to the multipath propagation, whereas the deterministic one can do it. In this way deterministic is more accurate, although empirical is simpler.