Investigation of rough surface scattering of electromagnetic waves using finite element method

Aşırım, Özüm Emre
This thesis analyzes the problem of electromagnetic wave scattering from rough surfaces using finite element method. Concepts like mesh generation and random rough surface generation will be discussed firstly. Then the fundamental concepts of the finite element method which are the functional form of a given partial differential equation, implementation of the element coefficient matrices, and the assemblage of elements will be discussed in detail. The rough surface and the overall mesh geometry will be implemented with the functional form of the wave equation, in the form of a global coefficient matrix using finite element method. Along with an incident wave, boundary conditions on the rough surface will be imposed and the scattering from different rough surfaces will be analyzed by solving the resulting linear system of equations that is yielded by the finite element method. The issues of wave resolution, required mesh size, and the required computation time will also be discussed as part of the analysis.


Investigation of electromagnetic wave propagation in double negative materials
Şen, Saffet Gökçen; Kuzuoğlu, Mustafa; Department of Electrical and Electronics Engineering (2008)
This thesis analyzes some aspects of electromagnetic wave propagation in double negative materials. Double negative materials have negative refractive indices. They are backward-wave materials. Plane waves undergo negative refraction at interfaces between double positive and double negative media. Causality principle implies these properties. High frequency plane wave scattering from a double negative infinitely long cylinder has been analyzed by using modified Watson transform, geometrical optics and Mie s...
Analysis of Composite Structures Involving Near-Zero-Index Materials
Koyaz, Yesim; İbili, Hande; Karaosmanoglu, Bariscan; Ergül, Özgür Salih (2019-01-01)
We consider numerical solutions of electromagnetic problems involving near-zero-index materials with permittivity and/or permeability values close to zero. These types of problems are inherently multiscale due to the large variety of the wavelength from very large values to ordinary values in the same problem. In addition to developing a stable formulation for extreme values of the intrinsic impedance, we employ a broadband multilevel fast multipole algorithm based on approximate diagonalization for efficie...
A Numerical Model for Investigating the Effect of Rough Surface Parameters on Radar Cross Section Statistics
Kuzuoğlu, Mustafa (2017-07-14)
Electromagnetic scattering from rough surfaces is modeled by combining the periodic finite element method and the transformation electromagnetics approach. The behavior of the radar cross section (RCS) at both specular and backscattering directions is analyzed as a function of rms height and correlation length with the help of Monte Carlo simulations. The concept of backscattering enhancement is illustrated, and some conclusions are drawn about the RCS statistics.
BULUTAY, C; PRASAD, S (1993-06-01)
Three-dimensional condensed asymmetrical node, variable grid, transmission-line matrix (TLM) method has been used in analyzing several millimeter waveguides on anisotropic substrates. The dispersion characteristics of image guides together with field and energy confinement properties at millimeter-wave frequencies have been investigated. Edge coupled microstrip line on a uniaxial substrate is analyzed for the even and odd mode dispersion characteristics. Finally the same analysis is repeated for bilateral f...
Modeling and Predicting Surface Roughness via Transformation Optics
Ozgun, O.; Kuzuoğlu, Mustafa (2014-08-28)
Monte Carlo analysis of surface roughness in electromagnetic scattering problems is presented by using the principles of transformation electromagnetics/optics in finite methods. The main motivation in the proposed approach is to eliminate the need of mesh generation for each surface in repeated Monte Carlo realizations, and hence, to devise a faster model in predicting surface roughness. A single, simple and uniform mesh is employed assuming a smooth surface and ignoring the actual surface, and thereafter,...
Citation Formats
Ö. E. Aşırım, “Investigation of rough surface scattering of electromagnetic waves using finite element method,” M.S. - Master of Science, Middle East Technical University, 2013.