A DOMAIN DECOMPOSITION METHOD FOR WAVEGUIDE HORNPROBLEMS USING THE FINITE ELEMENT METHOD

摘要

A Domain Decomposition Method (DDM) for solvingelectromagnetic radiation problems using the finiteelement method is proposed. To minimize the size of thecomputational domain, disjoint scatterers and/or radiatorswhich are relatively far from each others are boundedseparately. An iterative Absorbing Boundary Condition(ABC) is applied upon an outer boundary of arbitraryshape which may be conformal to the surface of eachscatterer and radiator. The boundary condition of eachsubdomain is updated iteratively using the contribution ofthe scattered field from the subdomain itself and alsofrom the other subdomains, which makes it fully coupled.An accurate waveguide port boundary condition isemployed to model horn antenna feeds. Unlike mostDDMs, the proposed method uses an arbitrary shapedtruncation boundary placed very close to the scatterersand radiators of each disjoint subdomain to minimize thecomputational domain; and more importantly, the methodproduces a solution that converges to the true solution (ifwe ignore discretization error) as the iteration proceeds.A numerical example is provided to demonstrate thecorrectness of the feed modelling by computing antennainput impedance. Results are provided to validate themulti-domain approach and compare it with the singledomain results.