A FEM Domain Decomposition Method With Non-conformal Grids For Microstrip Antenna

Computational electromagnetics has become an indispensable tool in electromagnetics、radio- frequency(RF) and antenna analysis,thanks to the rapidly increasing capability of modern electronic computers. When it comes to solving problems with tremendous dimension difference and local fine structure,(just as antenna with its waveguide feeding structure),the application of conventional finite element method(FEM)will lead to dense mesh in some part, and result in undesired mesh quality from the whole view and sharp increase of unknown numbers. A non-overlapping domain decomposition method(DDM) with non-matching grids combining finite element method has emerged as a powerful and attractive technique for simulation of problems with structures alike.In this dissertation, antenna feed modeling technique is studied at first, and a suitable truncation boundary condition is derived on the waveguide port so as to obtain a precise model that reflexes its geometry in the numerical simulation. Numerical experiment is carried out to demonstrate its validity and accuracy. Subsequently, a FEM domain decomposition method with non-conformal grids is presented for simulation of patch antenna fed by coaxial line where precise modeling is taken into account. According to the principles of DDM, the whole computational domain is divided into several sub-domains, a Robin-type condition is introduced at the interfaces to enforce the tangential field continuity. The non-conformal DDM enables each subdomain to be meshed independently, which brings convenience to design and analysis. Compared with conformal grids, non-conformal grids results in a tremendous reduction of the unknown number. Ultimately, reflection coefficient, input impedance and radiation pattern are obtained to demonstrate the efficiency and accuracy of non-conformal DDM.