Diseño y aplicación de un sistema de medida polivalente para la realización de ensayos de dispersión electromagnética sobre materiales y recubrimientos

Abstract

In the last decades, the use of electromagnetic fields has been widespread in a full range of scientific and technological fields. The aeronautical platforms, both civilian and military, have not been an exception. In fact, they have used them intensively or have suffered their use, been also pioneers in many of them, like for example the use of radar systems. In parallel, the materials and covers used in these platforms are been constantly renewed for improving their performance. Then, it is essential to characterize their behaviour not only from the mechanical or thermal point of view, for example, but also in relation to those electromagnetic fields. In this way, the design and implementation of novel facilities and measurement methods that improve this characterization are of great utility. In addition, a versatile conception that permits a great variety of tests on the same facility seems to be the path to follow in the current economical scene, providing a greater interest to the development due to the associated cost reduction. In this technological field the radar can be highlighted, which is able to detect any object that reflects an echo on the receiver higher that a predefined threshold, and also, it can determine its distance and position. Then, the reflectivity of a target is characterized by its Radar Cross Section (RCS). This is why its determination, analysis and control is of great interest, mainly in the military field. And not only for monostatic configuration, generalized in the operative systems, but also for bistatic configuration (transmitter and receiver placed in different locations), which is attracting the attention of the scientific and military community in the last years due to its ability to detect the so-called stealth targets. On the other hand, a system capable of electromagnetically characterize materials of interest share a great amount of characteristics with an RCS facility. Then it makes all sense to design a versatile system capable of performing not only RCS tests but also to measure the ability of a material to absorb electromagnetic energy, to estimate its electric permitivitty and magnetic permeability or to check the effect of antenna radomes and covers on their radiation pattern. Also, the same facility could be design to allow the implementation of near field antenna measurements (and its associated far field transformation) and, also, the research on procedures to extend this kind of transformations to the RCS determination. In this context, the dissertation deals with an innovative and unique measurement facility called BIstatic ANechoic CHAmber (BIANCHA), conceived, designed and constructed with the ability to perform all these kinds of test, all related to the research activities of the Detectability and Electronic Warfare Laboratory at Instituto Nacional de T´ecnica Aeroespacial “Esteban Terradas” (INTA). The facility has been developed with a multipurpose and versatile design, so that it permits the easy realization of monsotatic and bistatic measurements both in reflection and transmission, allowing to implement all those kinds of test enumerated. Among the broad amount of uses, the dissertation deals with the research and implementation of new radiation and dispersion measurement methods applied to the determination of the electromagnetic behaviour of advanced non-metallic materials and covers used in the aeronautic field, showing not only the developed methodology for each test but also measurement results that demonstrate the validity of the facility concept, design and implementation.