Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 18 of 18 for “"Rough Surface Scattering"”.
-
Kirchhoff approximation for rough surface scattering
Thesis: M.S., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1993
-
Applications of numerical models for rough surface scattering
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.
-
The Monte Carlo techniques with pulse compression for rough surface scattering
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1996, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering, 1996.
-
Rough surface scattering under Gaussian beam illumination and the Kirchhoff approximation
In this thesis, an analysis of the scattering of a rough perfect electric conductor (PEC) surface under illumination by a Gaussian beam using the Kirchhoff approximation is presented. The analysis assumes a source distribution which yields a Gaussian beam solution as a radiated field. This field is …
-
Rough Surface Scattering and Propagation over Rough Terrain in Ducting Environments
The problem of rough surface scattering and propagation over rough terrain in ducting environments has been receiving considerable attention in the literature. One popular method of modeling this problem is the parabolic wave equation (PWE) method. In this method, the Helmholtz wave equation is …
-
Effect of correlation between shadowing and shadowed points in rough surface scattering
Shadowing of random surfaces is accounted for by multiplying the Kirchhoff electric current density by a shadowing function. The shadow-corrected incoherent intensity is computed in the backscatter direction and is found to be proportional to the probability of a specular point being illuminated …
-
A Curvature-Corrected Rough Surface Scattering Theory Through The Single-Scatter Subtraction Method
… is presented to study radio propagation and rough surface scattering problems based on a reformulation of the Magnetic Field Integration Equation (MFIE) called the Single-Scatter Subtraction (S^3) method. This technique amounts to a physical preconditioning by separating the single- and …
-
A Study of Rough Surface Scattering Phenomena in the LMDS Band (28 GHz)
… study, the properties of the reflected paths and scattering phenomena were investigated in the LMDS band (28 GHz). We used the newly developed sampling swept time delay short pulse (SSTDSP) sounder to collect field data in certain locations on the Virginia Tech campus. The sounder collected the …
-
High-frequency electromagnetic wave scattering from rough surfaces
"A new technique in solving the rough surface scattering problem is presented. The method employed, entitled the ""shooting and bouncing rays"" (SBR) method, is based on a combination of the geometric optics (GO) theory and the physical optics (PO) theory. The SBR method improves on the Kirchhoff …
-
Acoustic mode coherence in the Arctic Ocean
… the central role played by the strong Arctic surface duct. The performance of each of four different modal beamforming algorithms when applied to the vertical array deployed during the FRAM IV Arctic Acoustic Experiment is analyzed. A multiple beam (or decoupled beam) least squares processor …
-
An integrated modal approach to surface and volume scattering in ocean acoustic waveguides
… random variations in ocean properties, including rough surfaces and volume fluctuations in the ocean or seabed. Such inhomogeneities scatter part of the incident acoustic field, stripping energy from the coherent part of the field. This scattered energy, or reverberation, propagates further in the …
-
Improving Electromagnetic Bias Estimates
… in the TOPEX/Poseidon and Jason-1 satellite sea surface height (SSH) estimates. Due to incomplete understanding of the physical processes which cause the bias, current operational models are based on empirical relationships between the bias wind speed and significant wave height. These models …
-
A Technique for Evaluating the Uncertainties in Path Loss Predictions Caused by Sparsely Sampled Terrain Data
… power loss in a communication link caused by the surface of the ground, atmospheric refraction, foliage, and other environmental factors. Many of the models rely on digital topographic databases to provide information about the terrain, and generally the databases are sparsely sampled relative to …
-
Applications in Remote Sensing Using the Method of Ordered Multiple Interactions
… to the integral<br />equations describing surface scattering which is both computationally efficient and reliably<br />convergent. The method has been applied in a variety of ways to solving the electromagnetic<br />scattering from perfectly-conducting rough surfaces. A desire to more …
-
Gaussian beam scattering from a deterministic rough metal surface
A full-wave theory of plane wave scattering from rough surfaces called the Correction Current (CC) method was recently developed for the two-dimensional scatter problem that have a one-dimensional roughness profile. The method involves a primary field and radiation modes that are plane-wave-type …
-
A Study of Electromagnetic Scattering of Communication Signals by Randomly Rough Surfaces
… to communication signal propagation studies through the use of Fourier decomposition thereby allowing the analysis and prediction of communication signals propagating over rough surfaces. Current methods of predicting and analyzing communication signal propagation rely on either using only a …
-
Propagation and Scattering of Waves by Terrain Features
… natural terrain features on the propagation and scattering of waves. It begins with the rough knife obstruction case, moves into rough surfaces and finally concludes with several approaches to a foliage covered rough surface. Each of these problems is encountered in radar, remote sensing and …