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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Computation Of Radar Cross Sections Of Complex Targets By Shooting And Bouncing Ray Method

Ozgun, Salim 01 September 2009 (has links) (PDF)
In this study, a MATLAB&reg / code based on the Shooting and Bouncing Ray (SBR) algorithm is developed to compute the Radar Cross Section (RCS) of complex targets. SBR is based on ray tracing and combine Geometric Optics (GO) and Physical Optics (PO) approaches to compute the RCS of arbitrary scatterers. The presented algorithm is examined in two parts / the first part addresses a new aperture selection strategy named as &ldquo / conformal aperture&rdquo / , which is proposed and formulated to increase the performance of the code outside the specular regions, and the second part is devoted to testing the multiple scattering and shadowing performance of the code. The conformal aperture approach consists of a configuration that gathers all rays bouncing back from the target, and calculates their contribution to RCS. Multiple scattering capability of the algorithm is verified and tested over simple shapes. Ray tracing part of the code is also used as v a shadowing algorithm. In the first instance, simple shapes like sphere, plate, cylinder and polyhedron are used to model simple targets. With primitive shapes, complex targets can be modeled up to some degree. Later, patch representation is used to model complex targets accurately. In order to test the whole code over complex targets, a Computer Aided Design (CAD) format known as Stereo Lithography (STL) mesh is used. Targets that are composed in CAD tools are imported in STL mesh format and handled in the code. Different sweep geometries are defined to compute the RCS of targets with respect to aspect angles. Complex targets are selected according to their RCS characteristics to test the code further. In addition to these, results are compared with PO, Method of Moments (MoM) and Multilevel Fast Multipole Method (MLFMM) results obtained from the FEKO software. These comparisons enabled us to improve the code as possible as it is.
2

Wavefront Control With Realistic Spatial Light Modulator in a Multi-aperture Imager

Wu, Guimin January 2012 (has links)
No description available.

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