Modelisation of a circuit microurban integrant a transistor (HBT) by a method iterative with auxiliary sources
In summary, auxiliary sources are modeled by an iterative method, a much more applied aspect to linked with the evolved functions. Which is able to be realized by the association of an active component (transistor HBT) with a passive planar structure, operating in the field of the microwaves.
Modélisation électromagnétique des circuits planaires : application à l'influence du boîtier
Ce travail de these est une contribution a la modelisation des circuits planaires en tenant compte des discontinuites aux differents acces du boitier. L'interet de modeliser les effets du blindage sur les discontinuites planaires apparait avec la necessite de disposer de modeles de circuits electriques equivalents compatibles avec les outils existants de CAO capables de predire le comportement du circuit dans son environnement reel de fonctionnement. Avec la montee en frequence et pour les applications specifiques, de nouvelles methodes numeriques permettant d'explorer des circuits planaires de geometries quelconques sont a developper. Dans cette contribution, une approche multimodale de resonance transverse est appliquee a la modelisation des discontinuites planaires blindees et des modeles de circuit electrique equivalent, prenant en compte l'influence des modes d'ordre superieur, elabores. Dans la deuxieme partie, une nouvelle methode iterative basee sur le concept d'onde" F. W. C. I. P, Fast Wave Concept Iterative Process" a ete developpee pour l'etude des structures planaires actives simples ou multicouches de forme arbitraire. L'avantage de cette methode est sa grande facilite de mise en oeuvre et sa rapidite d'execution essentiellement due a l'utilisation systematique d'une transformee rapide en modes. De sorte, le comportement d'une structure simple ou multicouche peut etre resume par des conditions aux limites exprimees a l'interface globale.
APPLICATION OF THE FINITE ELEMENT METHOD TO ROTARY-WING AEROELASTICITY.
Recent research in rotary-wing aeroelasticity has indicated that all fundamental problems in this area are inherently nonlinear. The non-linearities in this problem are due to the inclusion of finite slopes, due to moderate deflections, in the structural, inertia and aerodynamic operators associated with this aeroelastic problem. In this paper the equations of motion, which are both time and space dependent, for the aeroelastic problem are first formulated in P.D.E. form. Next the equations are linearized about a suitable equilibrium position. The spatial dependence in these equations is discretized using a local Galerkin method of weighted residuals resulting in a finite element formulation of the aeroelastic problem. As an illustration the method is applied to the coupled flap-lag problem of a helicopter rotor blade in hover. Comparison of the solutions with previously published solutions establishes the convergence properties of the method. It is concluded that this formulation is a practical tool for solving rotary-wing aeroelastic stability or response problems.