A technique that allows to locate defective elements in planar arrays by using some samples of the degraded far-field power pattern is described. This approach uses genetic algorithms to minimize the square of the difference between the far-field power pattern obtained for a given configuration of failed elements and the measured one. The method also allows to detect defective elements that don't fail completely

The performance of two minimal prototype antennas validates a novel design concept for a vehicle‐borne antenna for communications via satellite: the toroidal beam antenna implemented by a ring or rings of microstrip patches. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 39: 14–16, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11112

An overview about some of the recent Spanish developments on active reflectors is presented. In the first part, a novel beamsteering active reflectarray is deeply studied. It is based on implementing in each elementary radiator an IQ modulator structure, in which amplitude and phase control of the scattered field is achieved. Finally, a special effort is made in offering solutions to overcome the active antenna integration problems. In the second part, the active concept is firstly extended to Fresnel reflectors. Thanks to the development of a proper simulator, this special structure can be easily analysed. This simulator allows the study of performance of this kind of reflectors and, applying evolutionary algorithms, to find optimal configurations of reflector in accordance with the given specifications for the conformal radiation pattern.

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