Manuel Sierra Castañer

Comparison of Antenna Measurement Facilities With the DTU-ESA 12 GHz Validation Standard Antenna Within the EU Antenna Centre of Excellence

The primary objective of many antenna measurement facilities is to provide a specified high accuracy of the measured data. The validation of an antenna measurement facility is the process of proving that such a specified accuracy can be achieved. Since this constitutes a very challenging task, antenna measurement accuracy has been the subject of much research over many years and a range of useful measures have been introduced. Facility comparisons, together with antenna standards, error budgets, facility accreditations, and measurement procedure standards, constitute an effective measure towards facility validations. This paper documents the results of a comparison between 8 European antenna measurement facilities with a specially designed reference antenna, the DTU-ESA 12 GHz validation standard antenna (VAST-12). The electrical and mechanical properties of the VAST-12 antenna are presented and its three different coordinate systems are defined. The primary objective of the comparison is to obtain experience and results that can serve to develop standards for validation of antenna measurement facilities. The paper focuses on the comparison of the radiation pattern and presents not only the measurement data obtained at the facilities, but also investigates several procedures for comparing these data. This includes various definitions of pattern difference and statistical measures as well as a reference pattern. The comparison took place in 2004-2005 as part of the European Union network of excellence called ACE-Antenna Centre of Excellence.

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

The ‘Global Dimension in Engineering Education’ (GDEE) network is an initiative that aims to increase the awareness, critical understanding and attitudinal values of undergraduates and postgraduates students in technical universities across Europe related to Sustainable Human Development (SHD) and its relationship with technology. This is being dealt with by integrating SHD as a cross-cutting issue in teaching activities by improving the competences of academics and through engaging both staff and students in initiatives related to SHD. The GDEE started as a collaborative project between a consortium of European Universities and NGOs. The chapter presents a common understanding of how best to establish effective education for global development, and presents a pedagogical approach to facilitate the connection between theoretical knowledge (lecturers and students from universities) with practice (through NGOs). It discusses this approach through the analysis of case studies of best practice from those already working in this area within higher education across Europe. It concludes with the presentation of a continued professional development (CPD) approach for academics that uses a series of online training courses, with support from a series of contextual case studies written by NGOs to support teaching human development within engineering courses.

Linear polarization parallel plate slot antenna

We show the design of a linearly polarised flat antenna. The main goal is getting a low cost antenna to use for the reception of Hispasat satellite emissions in the 12 GHz band. The gain needed for the antenna is around 30 dBi. A rectangular array of slots in the upper side of a parallel plate waveguide form the main antenna structure. The guide is excited by one planar feeding structure consisting of an array of rectangular microstrip patches. We also modify the feeding network the design procedure and the materials used to build of the radiation surface.

Synthesis of circularly polarised multiprobe feed radial line slot array

In previous articles, we presented an easy way to analyze a slot array fed through a radial line and the design of an array of slots placed in an Archimedes spiral. The analysis was based on a circuit approach where the circuit parameters have been estimated using the first propagation mode in the radial line and the far field theory. The Archimedes spiral design, obtained with only one probe, has an efficiency problem due to the reflected field, that can be solved with this multiprobe design. The paper describes the antenna design method, giving the slot position and angle to obtain a radial line slot antenna having circular polarisation and broadside main beam.

Antenna Measurements at Millimeter and Submillimeter Wavelengths

Testing of electrically large, high-gain antennas as well as that of small integrated antennas at millimeter and submillimeter wavelengths is extremely challenging. Basically, there are three methods for measuring radiation properties of an antenna: the far-field method, the near-field method, and the compact antenna test range (CATR). In case of large antennas, the classical far-field method has two major obstacles at mm and submm wavelengths: impractically large measurement distance and high atmospheric loss. The planar near-field scanning method has been used up to 1 THz. However, the applied near-field methods often give useful information only on the main beam and its vicinity, because the field-sampling is typically very sparse. Reflector-based and hologram-based compact antenna test range (CATR) measurements have been demonstrated up to 500 GHz and 650 GHz, respectively. In the case of small integrated antennas, various techniques for on-wafer measurements have been developed. This chapter discusses the theory, techniques and limitations of the various test methods—the far-field method, planar near-field scanning and CATR as well as on-wafer measurements. Also, antenna pattern correction techniques are discussed.

Design of a 60GHz RLSA for compact range applications

The design of a 60GHz Radial Line Slot Antenna (RLSA) for compact range communications is discussed in this paper. A taper window was investigated and applied for a uniformly illuminated circular aperture in order to create a uniform field in a specified receiving zone. Predicted results show a good uniformity up to a few meters in the propagation distance, and on a receiving horizontal plane as large as the antenna aperture. A 20cm diameter RLSA prototype was fabricated based on the proposed taper design, and its measured results partly support our predictions.

Coupling estimation and compensation model for arrays of multimode radiators

In the design process of array antennas, coupling is one of the most important aspects to be considered to complete a realistic model. The real feeding radiated coefficients can be quite different from the theoretical ones because of this effect. A characterization and compensation model is presented. This procedure is able to match each element from the array. All the parameters of the array coupling model are obtained through scattering parameters and radiation pattern measurements. Some practical applications to linear patch arrays are presented.

Analysis and design software for radial slot antennas

A software for the analysis and design of radial slot antennas excited by one or several coaxial probes is presented. This tool has two main different blocks: analysis and design. The software has been improved with a file input/output options and a graphic display of radiation patterns, impedance, directivity and other antenna parameters. Everything is compiled in C++ for Windows. The second part of the paper includes some designs and results.