Date of Award

12-1995

Document Type

Thesis

Degree Name

Master of Science in Electrical Engineering

Department

Department of Electrical and Computer Engineering

First Advisor

Andrew Terzuoli, Jr., PhD

Abstract

The purpose of this study was to evaluate the effects of material characteristics uncertainties on Radar Cross Section (RCS) predictions. Many methods have been developed to predict the RCS of metal objects, but for material coated objects, these methods depend on the accuracy of measured material characteristics. Material characteristics of three dielectrics were measured by two separate X-band waveguide set-ups. RCS measurements were then made to evaluate the accuracy of RCS predictions using these measured material characteristics. A six inch square slab of each material was measured with and without a metal plate backing. A six inch square flat metal plate was also measured to qualify the accuracy of the range. RCS predictions were made using two methods. The first method calculated the reflection coefficients of the materials using transmission line theory and then applied physical optics theory to predict the RCS. The second method utilized Xpatch, a high frequency RCS prediction code. The comparison of RCS measurements to RCS predictions indicated that the X- band waveguide set-ups used were only able to accurately determine the effective material characteristics of thin homogeneous materials. The results of the correlation of material characteristic variations with corresponding RCS prediction variations were positive. In general, the variations in RCS predictions were correlated with the variations of the imaginary part of the dielectrics' permittivities. Qualitatively, the relative magnitude of these variations in the RCS predictions were highly correlated with the relative magnitude of the reflection coefficient.

AFIT Designator

AFIT-GE-ENG-95D-02

DTIC Accession Number

ADA309420

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