Scattering from Arbitrary Metal Particles: Using Green's Function Surface Integral Equation Method
Translated title
Spredning fra en Vilkårligt Udformet Metal Partikel: Greens Funktion Overfladeintegralligningsmetode
Author
Term
4. term (FYS10)
Education
Publication year
2020
Submitted on
2020-06-03
Pages
46
Abstract
Denne rapport handler om at modellere spredningen forårsaget af at en plan bølge rammer en metal partikel/spreder. Metallet antages at agerer som en perfekt elektrisk leder, og der er ikke nogle krav til udformningen af partiklen i forhold til symmetri. Modelleringen er baseret på Green’s Function Surface Integral Equation Method GFSIEM, mere specifikt bliver Magnetic Field Integral Equation MFIE brugt til at finde strømmen på sprederen. Både en simpel model baseret på en facetteret repræsentation af partiklens overflade, kaldet Facet Method, og en mere advanceret Curvilinear Method CM, som repræsenterer overfladen eksakt, bliver udviklet i denne rapport. Disse modeller bliver sammenlignet med den analytiske løsning for en sfære, der er god korrespondance mellem modellen og den analytiske løsning, især for CM, dog skal sprederen dikretiseres meget fint for små bølgelængder. CM bliver også sammen lignet med en cylinder symmetrisk version of GFSIEM for en stang spreder, også her giver begge modeller lignende resultater. Denne rapport gennemgår også hvilke ændringer der skal laves til Green’s Function hvis sprederen er nær en grænseovergang mellem to dielektrika i stedet for at være suspenderet i frit rum.
The purpose of this report is to model the scattering due to plane waves hitting metal particles of arbitrary shape, i.e. no symmetry is required for the scatterer. The metal is assumed to act like a perfect electric conductor PEC. The Green's Surface Integral Equation Method GFSIEM is used for modeling, specifically the Magnetic Field Integral Equation MFIE is used. Both a simple model based on a faceted representation of the scatterer surface, referred to as the Facet Method (FM) and a more advanced Curvilinear Model (CM) that represents the surface exactly is developed in this report. These models are compared to the analytical case of a sphere, and this shows good correspondence especially for the CM, however the scatter must be discretized very finely for small wavelengths. The CM is also compared to a GFSIEM model that uses cylindrical symmetry in the case of a rod, both methods give similar results. The report also delves into the modifications that must be made to Green's function if the scatter is near an interface of dielectrica, rather than situated in free space.
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