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The concept of an adaptive meshless eigenvalue solver is presented and implemented for two-dimensional structures. Based on radial basis functions, eigenmodes are calculated in a collocation approach for the second-order wave equation. This type of meshless method promises highly accurate results with the simplicity of a node-based collocation approach. Thus, when changing the discrete representation...
Boundary integral equations for bodies of revolution have a Green's function kernel that can be written as the azimuthal integral over the free-space Green's function. We show that existing approximation methods for computing this integral suffer from efficiency or stability problems. Improvement of one of these methods leads to controllable accuracy while retaining efficiency.
In this paper a statistical analysis of the impact of phase- and amplitude-distortions on the performance of active antenna arrays for mobile communication base stations is presented. The cause and influence of different contributors to these distortions is described and the allowable phase- and amplitude-margins that need to be reached for mobile communication base station applications are derived...
A predicting methodology of scattering by a cluster of multi-objects/systems is proposed in this paper. In this predicting methodology, a representation of scattering by each object/system in the cluster is formulated with plane waves. Then an equation based on this plane wave representation is established for formulating interaction among objects/systems in the cluster. Finally, the equation is efficiently...
The response of aperture-backed cavities and other highly resonant scatterers can pose difficulties for general purpose computational codes, in both time- and frequency-domain. An accurate, numerically efficient frequency domain solution is developed for the scalar wave diffraction problem from an arbitrary shaped body of revolution, either closed or having an aperture. The Dirichlet boundary condition...
When the Fast Hankel Transform filter technique is used to calculate the dyadic multilayered Green's functions, it can be difficult to obtain accurate numerical results because of the branch-cut singularity and the surface wave poles singularity. The Modified Fast Hankel Transform filter algorithm is proposed to overcome this problem by expressing the Bessel function with a complex argument as a sum...
Whispering gallery modes of a flat dielectric disk are studied by means of analytical and numerical computational methods based on the finite integration technique. The results are compared to a high accuracy measurement. The frequently used semi-analytical method of effective refractive index has certain weaknesses in finding accurate eigenfrequencies and quality factors.
The finite element-boundary integral-multilevel fast multipole algorithm (FE-BI-MLFMA) has shown to be very general and powerful for 3D scattering. To efficiently model cavity targets, a concave FE-BI-MLFMA is presented in this paper, which can significantly reduce the dispersion error from the FEM and improve the efficiency of FE-BI-MLFMA especially for nonuniform cavities. To eliminate the problem...
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