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Trabajo presenado a la European Conference on Antennas and Propagation. Roma, 2011. The capability of having many different beams illuminating the earth surface from a geostationary satellite has been an issue of interest during the last few years. The need of increasing the services provided by satellites urges the designers to propose different alternatives.

THz technology for developing imaging systems has recently aroused great interest, mainly due to the large number of applications in which these frequencies can be used: security, vision in hard environments, etc. In this paper we propose a method that reduces significantly the number of detectors needed for achieving certain resolution by means of diffraction that paradoxically is its main limiting factor in current imaging devices. The method uses diffraction as a way of achieving the advantages of the spatial diversity (information spread over a set of detectors) giving also the possibility to increase the resolution of the obtained images interpolating samples between detectors thanks to the slow variation function created by the diffraction phenomena.

Trabajo presentado al 32nd ESA Antenna Technology Workshop. Holanda, 2010. A spherical discrete lens antenna based on the back-toback combination of two choked-horn antennae arrays interconnected through smooth waveguides sections implementing the spherical phasing law, has been designed, simulated and fabricated. The spherical phasing law of the lens converts the incoming spherical phase front, from a small feeder placed at the focal plane, into a plane phase front. Depending on the feeder position at the focal plane (the perpendicular plane to the len's axis containing the focal point) the beam is pointed in different directions. The minimum angular distance between two beams is directly related to the minimum distance between two adjacent positions of low directive and, therefore, small feeders. The selected implementation offers several advantages compared to an actually curved lens, such as the simplification of the fabrication, the constant length of the phasing waveguides and the dispersion of the backscattered power, reducing significantly the coupling between feeders.

Trabajo presentado al 31st ESA Antennna Technology Workshop. Holanda, 2009. THz technology for developing imaging systems has recently aroused great interest, mainly due to the large number of applications in which these frequencies can be used: security, vision in hard environments, etc. The technological difficulties involved in producing a large number of detectors at these frequencies, proves to be a serious constrain that limits the possibilities of the whole system. It is frequently necessary for the camera to include some kind of moving mirrors in order to scan the entire vision field. We propose a method that significantly reduces the number of detectors needed for achieving a certain resolution by means of diffraction that paradoxically is the resolution limiting factor in current imaging devices. The method uses diffraction as a way of achieving spatial diversity and as an anti-aliasing LPF. Decimation is used to reduce the number of detectors.