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.
An iterative current-based hybrid method for complex structures
This paper presents a general unified hybrid method for radiation and scattering problems such as antennas mounted on a large platform. The method uses a coupled electric-field integral equation (EFIE) and magnetic-field integral equation (MFIE) formulation, referred to as the hybrid EFIE-MFIE (HEM), in which the EFIE and MFIE are applied to geometrically distinct regions of an object. The HEM is capable of modeling arbitrary three-dimensional (3-D) metallic structures, including wires and both open and closed surfaces. We show that current-based hybrid techniques that utilize physical optics (PO) are an approximation of the HEM formulation. A numerical solution procedure is given that combines the moment method (EFIE) with an iterative Neumann series technique (MFIE). This permits one to effectively utilize the PO approximation when appropriate, and provides a general and systematic mechanism to correct the errors introduced by PO. Consequently, the HEM overcomes the inherent limitations of hybrid techniques which rely upon ansatz-based improvements of PO. The method is applied to the problem of radiation from objects that can be modeled using wires and metallic surfaces as fundamental elements. A representative example is given to demonstrate that the method can handle the difficult problem of a parasitic monopole located in the deep shadow region.