Part 1. Space vehicles re-entering earth's atmosphere produce a shock wave which in turns results in a bow of plasma around the vehicle body. This plasma signicantly affects all radio links between the vehicle and ground, since the electron plasma frequency reaches beyond several GHz. In this work, a model of the propagation in plasma issue is developed. The radiofrequency propagation from/to antennae installed aboard the vehicle to the ground stations (or Data Relay Satellites) can be predicted, and the position of this antennae improved before a mission launch. Part 2. The Surface Integral Equation is one of the most used methods in the simulation of electromagnetic problems. The method used a discretized description of the surface on which a number of basis functions are needed. In the case of multi-scale structures, the test-object has regions with high details that require a fine mesh, together with flat surfaces where the current can be properly described with a coarser mesh. The goal of this work is to develop an automatic tool that identies the regions to be refined in a initial coarse mesh (dened only by geometry) using electromagnetic characteristics of the problem. It avoid the use of more unknowns that the actually needed (computational cost) and permits use a geometric mesh as base for different problems, adapting to each electromagnetic incidence automatically.

Efficient Electromagnetic Modelling of Complex Structures / TOBON VASQUEZ, JORGE ALBERTO. - (2014). [10.6092/polito/porto/2555144]

Efficient Electromagnetic Modelling of Complex Structures

TOBON VASQUEZ, JORGE ALBERTO
2014

Abstract

Part 1. Space vehicles re-entering earth's atmosphere produce a shock wave which in turns results in a bow of plasma around the vehicle body. This plasma signicantly affects all radio links between the vehicle and ground, since the electron plasma frequency reaches beyond several GHz. In this work, a model of the propagation in plasma issue is developed. The radiofrequency propagation from/to antennae installed aboard the vehicle to the ground stations (or Data Relay Satellites) can be predicted, and the position of this antennae improved before a mission launch. Part 2. The Surface Integral Equation is one of the most used methods in the simulation of electromagnetic problems. The method used a discretized description of the surface on which a number of basis functions are needed. In the case of multi-scale structures, the test-object has regions with high details that require a fine mesh, together with flat surfaces where the current can be properly described with a coarser mesh. The goal of this work is to develop an automatic tool that identies the regions to be refined in a initial coarse mesh (dened only by geometry) using electromagnetic characteristics of the problem. It avoid the use of more unknowns that the actually needed (computational cost) and permits use a geometric mesh as base for different problems, adapting to each electromagnetic incidence automatically.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2555144
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