Contribution à la conception de filtres reconfigurables sur la base de technologies planaires et SIW

This thesis began on October first, 2004, at the LEST (UMR CNRS 6165) within the framework of a co-operation with the university of Los Andes in Colombia, and with the financial support of program ALBAN. Two original ideas are presented in this work. They relate to the reconfigurability in bandwidth and central frequency of one of the strategic elements of telecommunication architectures: the filter. These two ideas relate to the agility, one related with planar technology and the other related with the SIW (Surface Integrated Waveguide) technology. The starting point is that it is difficult to obtain from traditional planar topologies a reconfigurable filter at the same time in central frequency and bandwidth, independently. To avoid these problems, we moved towards a nonconventional topology of filter developed at the LEST, the topology DBR (Dual Behavior Resonator). Our work consisted in proposing an original tuning solution based on the modification of the characteristic impedances of the stubs. The filters final prototype based on planar technologies is always very limited in term of electric performances. The quality factors are weak and make difficult to achieve strong requirements in term of specifications. The increase of the quality factor passes obligatorily by the implementation of new technologies. We thus propose to look in the second part of this thesis, reconfigurable filters based on cavities SIW (Substrate Integrated Waveguide). From this technology we developed a reconfigurable solution in central frequency and bandwidth, which moreover could be used for the applications in high frequency. The term SIW indicates that they are cavities integrated in a substrate. The objective here is to propose with the base of standard substrates, solutions remaining compatible with usual planar technologies and offering better performances thanks to the exploitation of the volume modes of resonances. On the basis of this solution, we thus developed a simple principle allowing to reach the tuning in central frequency and bandwidth.