The broad topic of the presented Ph.D. thesis consists in the research on novel methods in the field of microwave imaging, in particular the so-called passive microwave / millimeter-wave imaging, which is also referred to as radiometric imaging. This study focuses on proximity range applications such as concealed objects detection, human body screening, etc. These works has been carried out during a partnership with two teams in IETR : the department of " Antennas & Microwave Devices " and the department of " Progagation - Tracking & Remote Sensing ". The aim is to design a low cost and compact fully electronic passive imaging system suitable for short range 2D imaging applications, and study the necessary devices for the implementation of a complete demonstrator. The inoffensive character of the device is ensured by the lack of active emitter devices. Imaging is done by the interferometric synthetic aperture technique. The hard work is therefore concerned the definition of the system architecture and its optimization. In this study, to improve the cost-performance of the imaging systems, a new approach based on the use of a switch sub-matrix strategy for a passive imaging system is presented and discussed. The synthesis of planar arrays that is able to yield optimal sparse arrays with a low-redundancy and an optimized switching process is then proposed. This approach has been adapted into a complete antenna system at X band and millimeter-wave band. The objectives of these prototypes is to validate at first this approach experimentally, and then validate the principle of system calibration to process real data for image reconstruction.
