PhD Defense of Matthieu BERTRAND

The last decades have seen the evolution of communication networks toward greater complexity and efficiency, being now able to carry significant data rates.
This evolution is the result of both scientific and technological breakthroughs. Thanks
to the wide bandwidths available at millimeter-wave frequencies, the future generations
will be able to supply for the increasing demand in multimedia services, especially
high-definition videos. The design of wireless systems which operate at high frequencies with acceptable efficiency, costs, and minimum size thus constitute a decisive challenge.In this context, this work focuses on the development of passive circuits such as filters,couplers and waveguides which address these issues. We developed a miniaturization technique for printed circuits technology, which in a first step is dedicated to frequencies below 20 GHz. This technique is based on a slow-wave concept, defined as the property of any structure which imposes lower velocities to the electromagnetic waves. A theoretical analysis, as well as design methods were established and confirmed by measurements.
Secondly, we proposed two distinct technological solutions for the integration of efficient waveguides at millimeter-wave frequencies. This work was achieved in collaboration with two other laboratories. A theoretical study, design of test features and measurements were performed. These results intend to constitute a basis for the future realization of miniaturized slow-wave circuits at millimeter-wave frequency bands.