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Title:Theory and Experiments of Scattering From Microscale Random Rough and Deterministic Surfaces
Author(s):Tang, Kakuen
Doctoral Committee Chair(s):Buckius, Richard O.
Department / Program:Mechanical Engineering
Discipline:Mechanical Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Engineering, Mechanical
Abstract:Surface scattering has received considerable attention in the last few decades and is of interest in various engineering disciplines including thermal system design, optical remote sensing and photorealistic image generation. A combined experimental and theoretical investigation has been conducted for surfaces which have surface length scales on the order of the incident wavelength. A Fourier Transform Infrared Spectrometer (FTIR) is used for experimental measurements from two-dimensional rough random surfaces, and one- and two-dimensional deterministic samples. The two-dimensional deterministic surfaces are fabricated in a manner similar to the manufacturing of Micro-Electro-Mechanical Systems (MEMS). Rigorous electromagnetic theory analysis is used to demonstrate the influence of the surface materials, incident wavelength, incident angles and surface geometric parameters on the reflection distribution. A geometric optics approximation to the rigorous electromagnetic theory is developed for random rough surfaces. The approximate results agree well with the FTIR experimental findings, indicating that the geometric optics approximation provides a relatively simple approach to quantify surface scattering for its validity domain. Furthermore, this approximation can predict specular, diffuse and retro-reflection characteristics. A statistical method is developed based on the geometric optics approximation. Although this model has a smaller domain of application compared to the geometric optics approximation, it provides accurate trend predictions and is computationally inexpensive. For one-dimensional deterministic samples, rigorous electromagnetic theory calculations are necessary, and the experimental findings are in good agreement with the theoretical predictions. The samples exhibit specular reflection for longer incident wavelengths, and modal reflection is observed for short incident wavelengths. For two-dimensional surfaces, the experimental results indicate that the one-dimensional rigorous electromagnetic theory can predict modal reflection only in specific and limited cases.
Issue Date:1998
Description:168 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1998.
Other Identifier(s):(MiAaPQ)AAI9912395
Date Available in IDEALS:2015-09-25
Date Deposited:1998

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