Abstract EN:

This thesis presents original approaches for simulation, modeling and characterization of circuits exploiting picosecond FETs. The study is validated through a constant comparison between measurements and simulations of the large signal time domain response of a picosecond FET. The main goal is the accurate prediction of the rise time and wave shapes in ultra fast switching circuits. The study includes:1- Design of a novel time simulator MACPRO (MACromodular simulation with PROpagation) which exploits the method of characteristics and macromodeling for the treatment of propagation effects along single or coupled transmission lines (chapter I). 2- The developement of a novel large signal modeling: -a/ A FET electric model whose non linear elements are described directly with numerical 2D look-up tables as a function of the internai bias voltages of the transistor. This description is independent of analytical and mathematical expressions. B/ A novel extraction method which gives an accurate determination of the FET parameters from electric and microwave small signal characterizations. The potential of the HP8510 automatic network anlyser and of an optimization program are exploited for this method (chapter ll). Chapters III and IV present respectively the experimental strong signal step response of a picosecond FET and the generation of a large and fast signal positive step as well as the corresponding results of simulation.