Error Analysis and Simulator in Cylindrical Near-Field Antenna Measurement Systems

Large antennas need special measurement systems because of their considerable dimensions. Typically, cylindrical near-field systems are appropriate measurement systems for omnidirectional antennas due to the characteristics of their radiation patterns. Furthermore, these systems are also appropriate for sizeable RADAR antennas, since they can be measured on their azimuthal positioner and the probe can be easily translated through a vertical linear slide. Thus, mechanical aspects of measurement systems are rather important since errors in the mechanical set-up can directly affect far-field radiation patterns. This chapter presents an error estimation tool to analyze the most important errors for large L-band RADAR antennas in an outdoor cylindrical acquisition system and the effect of these errors in the calculated far-field radiation pattern. This analysis can be very convenient to evaluate the error budget of the Antenna Under Test (AUT). The simulator computes the far-field with an array of vertical dipoles over a ground plane and compares an ideal infinite far-field with the electric field obtained using the cylindrical near-to-far-field (NF-FF) transformation algorithm. The influence of the inaccuracies on the final results is evaluated by introducing random and systematic sources of errors and then, analyzing the variations produced in the principal far-field patterns, antenna parameters and in the side lobe levels (SLL). Finally, this simulator can be employed to analyze the errors for L-band RADAR antennas. One of the objectives of this investigation is thus to analyse how mechanical and electrical inaccuracies could affect the results of a cylindrical antenna measurement system, in order to minimize them as much as possible. This is highly important not only to meet the specifications, but also to reach high accurate results. There are several error sources studies for near-field patterns: the most complete are the ones developed by Joy and Newell in [Joy, 1988], [Newell, 1988], [Newell & Stubenrauch, 1988] and Hansen in [Hansen, 1988]. Later on, other investigations have been carried out analyzing precise error studies. Another goal is the a-priori uncertainty analysis of these errors in the measurement of Lband RADAR antennas, detecting which are the main error sources for each antenn

Promoting sustainable human development in engineering: Assessment of online courses within continuing professional development strategies

Higher Education Institutions play a critical role in societies transition towards sustainable development, educating future professionals and decision makers. In the last few decades, a number of technical universities have devoted major efforts to integrating sustainable development into engineering curricula. There is still, however, an increasing need to further transform learning and training environments and build capacity of educators and trainers on sustainable development issues. Against this background, this paper assesses the role of online training courses, within continuing professional development strategies, in promoting sustainable human development in engineering degrees. It was built upon the implementation of a European initiative, the Global Dimension in Engineering Education, promoted by a transdisciplinary consortium of technical universities and non-governmental organisations. In terms of method, this study analyses two sets of quantitative and qualitative indicators to assess i) the perceived quality/relevance of the training proposals, and ii) the learning acquisition of participants. Quantitative indicators were complemented by a descriptive analysis of findings from a semi-structured survey. The results provide evidence that online learning can be an effective approach for continuing professional development of academics. The findings also suggest that participants perceived online courses’ contents and curricula, developed jointly by academics and practitioners of non-governmental organisations, as relevant and useful for integrating sustainability principles in teaching activities. To conclude, authors recommend the leaders of higher educational institutions to explore the integration of online courses addressed to faculty into university policy and strategies, as a way to promote professional development and the engagement of academics on sustainable development

Testing new tools for introducing the global dimension in engineering education

Testing new tools for introducing the global dimension in engineering educatio

Facility comparison and evaluation using dual ridge horn

Comparative measurements at 25 frequencies have been performed on a dual ridge horn involving four different test facilities in the 1.55-6GHz range. The comparison of large amounts of measured data is unfeasible by inspection of pattern differences and should not be limited to studying boresight differences alone. Therefore a statistical approach has been implemented for the fast evaluation of large amounts of measurement data

Integrating the global dimension in engineering education: experiences from a collaborative project

This book introduces readers to the latest research and findings from projects focusing on teaching education for sustainable development at universities