An efficient fringe integral equation method for optimizing the antenna location on complex bodies

The radiation pattern of an antenna mounted nearby, or directly on, a complex three-dimensional (3D) structure can be significantly influenced by this structure. Integral equations combined with the method of moments (MoM) provide an accurate means for calculating the scattering from the structures in such applications. The structure is then modelled by triangular or rectangular surface patches with corresponding surface current expansion functions. A MoM matrix which is independent of the antenna location can be obtained by modelling the antenna as an impressed electric or magnetic source, e.g., a slot antenna can be modelled by a magnetic Hertzian dipole. For flush-mounted antennas, or antennas mounted in close vicinity of the scattering structure, the nearby impressed source induces a highly peaked surface current on the scattering structure. For the low-order basis functions usually applied in conventional integral equation solvers, a peaked current poses a challenging problem since it necessitates a large number of unknowns and excessive computation times. A fringe dual-surface magnetic field integral equation (F-DMFIE) that eliminates the problem of peaked currents and fields, even for impressed sources located arbitrarily close to the surface of the structure, was presented by Jorgensen, Meincke and Breinbjerg (see Proc. of the Applied Computational Electromagnetic Symp., Monterey, CA,. March 2001). In this formulation, the surface current on the structure is obtained by evaluating a number of line integrals and performing a single matrix-vector multiplication for each antenna location. This paper reviews the F-DMFIE formulation and applies it to a more complicated geometry than that of Jorgensen et al. In addition, efficient solution methods for multiple antenna locations, including parallel implementations, are discussed.