A Domain Decomposition Method for Waveguide Horn Problems using the Finite Element Method

P. Paul and J.P. Webb (Canada)


Wave propagation, radiation, domain decomposition method (DDM), feed modelling, absorbing boundary condition (ABC), horn antenna.


A Domain Decomposition Method (DDM) for solving electromagnetic radiation problems using the finite element method is proposed. To minimize the size of the computational domain, disjoint scatterers and/or radiators which are relatively far from each others are bounded separately. An iterative Absorbing Boundary Condition (ABC) is applied upon an outer boundary of arbitrary shape which may be conformal to the surface of each scatterer and radiator. The boundary condition of each subdomain is updated iteratively using the contribution of the scattered field from the subdomain itself and also from the other subdomains, which makes it fully coupled. An accurate waveguide port boundary condition is employed to model horn antenna feeds. Unlike most DDMs, the proposed method uses an arbitrary shaped truncation boundary placed very close to the scatterers and radiators of each disjoint subdomain to minimize the computational domain; and more importantly, the method produces a solution that converges to the true solution (if we ignore discretization error) as the iteration proceeds. A numerical example is provided to demonstrate the correctness of the feed modelling by computing antenna input impedance. Results are provided to validate the multi-domain approach and compare it with the single domain results.

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