Infrared antennas are employed in sensing applications requiring specific spectral, polarization, and directional properties. Because of their inherently small dimensions, there is significant interaction, both thermal and electromagnetic, between the antenna, the antenna-coupled sensor, and the low-frequency readout structures necessary for signal extraction at the baseband modulation frequency. Validation of design models against measurements requires separation of these effects so that the response of the antenna-coupled sensor alone can be measured in a calibrated manner. Such validations will allow confident extension of design techniques to more complex infrared-antenna configurations. Two general techniques are explored to accomplish this goal. The extraneous signal contributions can be measured separately with calibration structures closely co-located near the devices to be characterized. This approach is demonstrated in two specific embodiments, for removal of cross-polarization effects arising from lead lines in an antenna-coupled infrared dipole, and for removal of distributed thermal effects in an infrared phased-array antenna. The second calibration technique uses scanning near-field microscopy to experimentally determine the spatial dependence of the electric-field distributions on the signal-extraction structures, and to include these measured fields in the computational electromagnetic model of the overall device. This approach is demonstrated for infrared dipole antennas which are connected to coplanar strip lines. Specific situations with open-circuit and short-circuit impedances at the termination of the lines are investigated.

La demande de matériaux transparents dans l’infrarouge et notamment dans la région de 2 à 5 μm est de plus en plus croissante. Plusieurs familles de verre transmettent dans l’infrarouge de manière plus ou moins étendue, cependant leur fabrication complexe, leur faible résistance mécanique ou chimique ou encore leurs éléments constitutifs limitent leur mise en forme et leurs applications. Les verres d’oxydes de métaux lourds à base d’oxyde de gallium (Ga2O3) constituent d’excellents candidats à condition qu’ils puissent être mis en forme. Les travaux exposés dans cette thèse portent sur l’étude des propriétés et de la structure locale de trois systèmes vitreux riches en oxyde de gallium : GaO3/2-GeO2-NaO1/2, GaO3/2-LaO3/2-KO1/2-NbO3/2 et GaO3/2-GeO2-BaO-KO1/2. Les propriétés mécaniques, une étude de dévitrification, et la fabrication de fibre optique au moyen de différentes techniques (préforme, poudre dans tube, barreau dans tube et à partir d’un creuset ouvert) ont été réalisées sur une composition du système vitreux GaO3/2-GeO2-BaO-KO1/2. / The demand for transparent material in the specific infrared region from 2 to 5 μm is increasing. Several glass compositions present an extended transmission in the infrared, however their complex synthesis process, their poor mechanical or chemical resistance as well as their compounds restricted their shaping and applications. Gallium oxide (Ga2O3) based heavy metal oxide glasses represent excellent candidates if they can be shaped. The work exposed in this thesis focuses on the properties and the local structure study of three gallium oxide rich vitreous systems: GaO3/2-GeO2-NaO1/2, GaO3/2-LaO3/2-KO1/2-NbO3/2 and GaO3/2-GeO2-BaO-KO1/2. For a specific composition in the glass system GaO3/2-GeO2-BaO-KO1/2, mechanical properties, devitrification study as well as fiber drawing by different techniques (preform, powder in tube, rod in tube and from an open crucible) have been investigated.